build: share maintained ESP32 cache

feat: merge Home Assistant MQTT compatibility release

.github/FUNDING.yml

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+github: dawidchyrzynski

.github/workflows/ci.yml

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+name: Build
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+
+concurrency:
+  group: build-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  documentation:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: bash -n scripts/*.sh
+      - run: ./scripts/check-docs.sh
+  native-core-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - run: python -m pip install --upgrade platformio==6.1.19
+      - run: pio test -e native --filter test_native_core
+
+  compile-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        platform: [esp8266, esp32]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - run: python -m pip install --upgrade platformio==6.1.19
+      - run: ./scripts/test.sh compile --platform ${{ matrix.platform }}
+      - run: ./scripts/test.sh examples --platform ${{ matrix.platform }}

.github/workflows/ha-test-harness.yml

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+name: Home Assistant MQTT test harness
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "17 3 * * 1"
+
+permissions:
+  contents: read
+
+jobs:
+  test_harness:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - home_assistant: "2024.11.3"
+            expect_disabled_cleanup: "0"
+          - home_assistant: stable
+            expect_disabled_cleanup: "0"
+          - home_assistant: dev
+            expect_disabled_cleanup: "1"
+    env:
+      HA_VERSION: ${{ matrix.home_assistant }}
+      TEST_HARNESS_EXPECT_DISABLED_CLEANUP: ${{ matrix.expect_disabled_cleanup }}
+      COMPOSE_FILE: tests/ha-test-harness/compose.yaml
+    steps:
+      - uses: actions/checkout@v4
+      - name: Start broker and Home Assistant
+        run: docker compose up -d mqtt homeassistant
+      - name: Check single-to-device migration
+        run: docker compose run --rm tests
+      - name: Restart Home Assistant from retained data
+        run: docker compose restart homeassistant
+      - name: Check retained discovery after restart
+        run: docker compose run --rm -e TEST_HARNESS_MODE=retained-restart tests
+      - name: Collect Home Assistant logs on failure
+        if: failure()
+        run: docker compose logs --no-color homeassistant mqtt
+      - name: Remove test harness volumes
+        if: always()
+        run: docker compose down -v

.github/workflows/release.yml

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+name: Publish release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+
+jobs:
+  test_harness:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - home_assistant: "2024.11.3"
+          - home_assistant: stable
+    env:
+      HA_VERSION: ${{ matrix.home_assistant }}
+      TEST_HARNESS_EXPECT_DISABLED_CLEANUP: "0"
+      COMPOSE_FILE: tests/ha-test-harness/compose.yaml
+    steps:
+      - uses: actions/checkout@v4
+      - name: Start broker and Home Assistant
+        run: docker compose up -d mqtt homeassistant
+      - name: Check single-to-device migration
+        run: docker compose run --rm tests
+      - name: Restart Home Assistant from retained data
+        run: docker compose restart homeassistant
+      - name: Check retained discovery after restart
+        run: docker compose run --rm -e TEST_HARNESS_MODE=retained-restart tests
+      - name: Collect Home Assistant logs on failure
+        if: failure()
+        run: docker compose logs --no-color homeassistant mqtt
+      - name: Remove test harness volumes
+        if: always()
+        run: docker compose down -v
+  publish:
+    runs-on: ubuntu-latest
+    needs: test_harness
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - run: python -m pip install --upgrade platformio==6.1.19
+      - run: ./scripts/test.sh compile --platform esp8266
+      - run: ./scripts/test.sh examples --platform esp8266
+      - run: pio test -e native --filter test_native_core
+      - run: ./scripts/test.sh compile --platform esp32
+      - run: ./scripts/test.sh examples --platform esp32
+      - run: ./scripts/check-docs.sh
+      - run: ./scripts/prepare-release.sh "$GITHUB_REF_NAME"
+      - run: ./scripts/release-notes.sh "$GITHUB_REF_NAME" > "$RUNNER_TEMP/release-notes.md"
+      - run: gh release create "$GITHUB_REF_NAME" --title "ArduinoHA $GITHUB_REF_NAME" --notes-file "$RUNNER_TEMP/release-notes.md"
+        env:
+          GH_TOKEN: ${{ github.token }}

.gitignore

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+.DS_Store
+tmp/
+
+# Python test tooling
+__pycache__/
+*.py[cod]
+
+# PlatformIO build output
+.pio/
+
+# Sphinx inventory (legacy); we ship Markdown-only under docs/
+docs/*.inv
+
+# Cursor IDE (local rules, not part of the library)
+.cursor/

CHANGELOG.md

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+# Changelog
+
+## 3.2.1
+
+- Clarify discovery migration and entity documentation, including the choices
+  for new devices, existing installations, and no-device-discovery projects.
+- Refresh the canonical PlatformIO and Arduino IDE package metadata.
+
+## 3.2.0
+
+**Discovery publication and resilience:**
+
+- Batch direct MQTT discovery writes into bounded 128-byte chunks, avoiding hundreds of tiny TCP writes while preserving streaming payload generation.
+- Treat allocation or streaming failure as a failed discovery publication, discard the unfinished payload, and reconnect before the next retained update.
+- Allocate device-discovery component serializers only for sizing and emission, reducing peak heap use; make serializer allocation failure safe.
+
+**Compatibility, tests, and documentation:**
+
+- Add the reusable, Docker-based HA/MQTT testkit and run ArduinoHA migration and retained-restart checks against Home Assistant 2024.11.3, stable, and dev.
+- Make the fixed baseline and current stable test-harness lanes release gates; keep the rolling dev lane scheduled/manual.
+- Add maintained, credential-free PlatformIO ESP8266/ESP32 example projects and compile them in CI.
+
+## 3.1.0
+
+**Home Assistant MQTT compatibility:**
+
+- Add an explicit, retry-safe single-component to device-discovery migration sequence: retained `migrate_discovery` markers, device config, then legacy-topic cleanup.
+- Match Home Assistant device-component removal semantics with a platform-only tombstone followed by a compacted payload; `republishDiscovery()` re-adds a removed component.
+- Stop serializing removed `obj_id`; keep `setObjectId()` source-compatible and use `setDefaultEntityId()` for new entities.
+
+**Reliability and maintenance:**
+
+- Reject invalid discovery topic tokens, escape dynamic JSON values, and fail discovery publication on partial writes or missing device IDs.
+- Register entities safely regardless of whether they are constructed before or after `HAMqtt`, diagnose entity-limit drops, and make explicit disconnect callbacks observable.
+- Make `HAText` own its current state and bounded command copy; align device-discovery origin version with the package version.
+- Add native AddressSanitizer/UndefinedBehaviorSanitizer core regression coverage and release-script version consistency checks.
+
+## 3.0.2
+
+- Align the Arduino IDE `library.properties` version with `library.json` so both package formats identify the same release.
+
+
+## 3.0.1
+
+- Build and test against the Arduino 3-compatible pioarduino ESP32 platform.
+- Enable the integer overload expected by Arduino-ESP32 3 while preserving the
+  existing ArduinoHA public API.
+
+## 3.0.0
+
+- Establish this maintained fork as the canonical ArduinoHA dependency for DeviceFramework.
+- Prevent discovery serialization from writing past its entry allocation.
+- Correct array deallocation in affected entity types.
+
+**New features:**
+* Added support for the `default_entity_id` (`def_ent_id`) discovery property across device types. New code should prefer `setDefaultEntityId()` over `setObjectId()`.
+* Added opt-in MQTT device discovery payload support through `HAMqtt::enableDeviceDiscovery()`, while keeping single-component discovery as the default behavior.
+* Added `HABaseDeviceType::removeFromDiscovery()` and `HABaseDeviceType::republishDiscovery()` helpers for explicit discovery lifecycle management.
+* Added support for the `entity_category` property across the exposed MQTT device types.
+
+**Fixes:**
+* Fixed discovery refresh behavior for runtime config updates so device discovery mode clears stale retained per-entity configs before republishing device payloads.
+* Fixed `HANumber::updateMinMaxStep()` so discovery updates follow the active discovery mode instead of always writing a retained per-entity config.
+* Ignore empty `unit_of_measurement` values in discovery payloads.
+* Allow `HANumber` configurations where `min` is equal to `max`.
+
+**Migration notes:**
+* Unit tests now live under `test/` as PlatformIO Unity suites (`pio test`). The legacy `tests/` tree (AUnit, EpoxyDuino, Make, AUniter) has been removed.
+* Home Assistant deprecated MQTT `object_id` in favor of `default_entity_id`, and newer Home Assistant versions may warn on or remove `object_id` handling in discovery payloads.
+* `setObjectId()` remains source-compatible but no longer serializes the removed `obj_id` discovery property; new projects should use `setDefaultEntityId()`.
+* Existing single-component devices must use the staged migration API before device discovery; use `republishDiscovery()` when a runtime config change needs to refresh discovery state.
+
+## 2.1.0
+
+**New features:**
+* Added support for setting MQTT's keep alive [#153](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/153) by [@allenb2800](https://github.com/allenb2800)
+* Added support for the `state_class` property in the `HASensor` [#179](https://github.com/dawidchyrzynski/arduino-home-assistant/pull/179)
+* Implemented extended unique ID support for all device types. This allows you to prefix each device type's unique ID with the device ID, ensuring smooth deployment of identical code on multiple devices without encountering unique ID conflicts [#212](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/212)
+* Added support for the `configuration_url` property in the `HADevice` [#182](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/182)
+* Added `getCurrentOption` method to the `HASelect` device type [#163](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/163)
+* Added support for publishing the `None` state in the `HASelect` device type [#146](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/146)
+* Added support for publishing the `None` state in the `HASensor` device type [#175](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/175)
+* Added support for the `expire_after` property in the `HASensor` [#171](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/171)
+* Added support for the `expire_after` property in the `HABinarySensor` [#159](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/159)
+* Added support for the JSON attributes in the `HASensor`
+* Added support for the `object_id` property in all device types
+* Added `setBufferSize` method to the `HAMqtt` class [#202](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/202)
+* Added `getState` method to the `HAMqtt` class
+* Added `onDisconnected` callback method to the `HAMqtt` class
+* Added `onStateChanged` callback method to the `HAMqtt` class
+* Added support for Arduino Due [#137](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/137)
+
+**Fixes:**
+* Fixed a bug with the maximum number of device types [#190](https://github.com/dawidchyrzynski/arduino-home-assistant/issues/190) by [@martaisty](https://github.com/martaisty)
+* Fixed compiler warning: `class 'HANumeric' is implicitly friends with itself` [#197](https://github.com/dawidchyrzynski/arduino-home-assistant/pull/197) by [@shedokan](https://github.com/shedokan)
+* The default limit for device types has been raised to 24 on processors other than ATMega328/ATMega168. The previous default limit of 6 led to confusion for many users.
+
+## 2.0.0
+
+**New features:**
+
+* Added support for the `icon` property in the `HABinarySensor` (you can set the icon using `HABinarySensor::setIcon("iconName")`)
+* Added support for changing the current state of the `HABinarySensor` using `HABinarySensor::setCurrentState` method
+* Added support for forcing `setState` in `HABinarySensor` using a second argument as follows `HABinarySensor::setState(true, true)`
+* Added support for the `device_class` property in the `HACover` (you can set the class using `HACover::setDeviceClass("className")`
+* Added support for the `icon` property in the `HACover` (you can set the icon using `HACover::setIcon("iconName")`)
+* Added pointer of the sender to the `HACover` callback function
+* Added support for `optimistic` property in the `HACover` (you can change the mode using `HACover::setOptimistic(true)`)
+* Added support for forcing `setPosition` in `HACover` using a second argument as follows `HACover::setPosition(100, true)`
+* Added support for the `device_class` property in the `HASwitch` (you can set the class using `HASwitch::setDeviceClass("className")`
+* Added support for the `optimistic` property in the `HASwitch` (you can change the mode using `HASwitch::setOptimistic(true)`)
+* Added support for the `force_update` property in the `HASensor` (you can set the mode using `HASensor::setForceUpdate(true)`)
+* Added support for the `HAButton` device type
+* Added support for the `HADeviceTracker` device type
+* Added support for the `HACamera` device type
+* Added support for the `HALock` device type
+* Added support for the `HASelect` device type
+* Added support for the `HANumber` device type
+* Added support for the `HAScene` device type
+* Added support for the `HALight` device type
+
+**Fixes:**
+* Last Will Message is now retained (#70)
+* Compilation error on SAMD family (#82)
+
+**New examples:**
+* [Button](examples/button/button.ino) - adding simple buttons to the Home Assistant panel.
+
+**Breaking changes:**
+
+* Changed structure of all MQTT topics used in the library.
+* Changed constructor of the `HABinarySensor` class (removed `deviceClass` and `initialState` arguments)
+* Renamed `HABinarySensor::getState()` method to `HABinarySensor::getCurrentState()`
+* Replaced `HATriggers` with `HADeviceTrigger` - the new implementation is not backward compatible. Please check the updated example of the `multi-state-button`.
+* Renamed `HADevice::isOnline()` method to `HADevice::isAvailable()`
+* Renamed `HASwitch::onStateChanged` method to `HASwitch::onCommand`.
+* Renamed `HAFan::onStateChanged` method to `HAFan::onStateCommand`.
+* Renamed `HAFan::onSpeedChanged` method to `HAFan::onSpeedCommand`.
+* Changed logic of the `HASwitch` callback. Please check the `led-switch` example.
+* Refactored `HASensor` logic. It's now divided into two different classes: `HASensor` and `HASensorNumber`.
+* Removed all legacy constructors with `HAMqtt` argument
+* Removed `onConnectionFailed` callback from the `HAMqtt` class
+* The position in the `HACover` is now available as configurable feature. It's disabled by default.
+* Refactored `HAHVAC` class to support more features of the MQTT discovery. Please check the update example.
+
+## 1.3.0
+
+**New features:**
+* Added `onMessage()` method to HAMqtt class
+* Added support for HA Covers
+* Added support for setting different prefix for non-discovery topics (see [Advanced MQTT example](examples/mqtt-advanced/mqtt-advanced.ino))
+* Added `setName` method to HASensor
+* Added `setName` method to HASwitch
+* Added `onBeforeStateChanged` callback to HASwitch
+
+**Improvements:**
+* Removed legacy properties from HAFan (Home Assistant 2021.4.4). Deprecated methods will be removed after a quarter (2021.7)
+* Separated `uniqueID` field from `name` in all devices types
+
+## 1.2.0
+
+**Breaking changes:**
+* Refactored HASensor implementation. Please take a look at [updated example](examples/sensor/sensor.ino)
+
+**New features:**
+* Added support for HVAC
+* Added support for excluding devices types from the compilation using defines (see [src/ArduinoHADefines.h](src/ArduinoHADefines.h))
+* Added support for setting icon in HASwitch and HASensor
+* Added support for setting retain flag in HASwitch
+* Added support for text (const char*) payload in HASensor
+* Added support for fans (HAFan)
+* Added support for connecting to the MQTT broker using hostname
+* Added `onConnected()` method in the HAMqtt
+* Added `onConnectionFailed()` method in the HAMqtt
+* Added support for MQTT LWT (see [Advanced Availability example](examples/advanced-availability/advanced-availability.ino))
+
+**Improvements:**
+* Optimized codebase and logic in all devices types
+* Updated all examples
+* Fixed compilation warnings in all classes

LICENSE

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+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
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+<https://www.gnu.org/licenses/>.

README.md

@@ -1,58 +1,69 @@
 # Arduino Home Assistant integration
 
-ArduinoHA allows to integrate an Arduino/ESP based device with Home Assistant using MQTT.
-The library is designed to use as little resources (RAM/flash) as possible.
-Initially it was optimized to work on Arduino Uno with Ethernet Shield,
-but I successfully use it on ESP8266/ESP8255 boards in my projects.
+[![](https://img.shields.io/github/v/release/alexhopeoconnor/arduino-home-assistant?label=Version)](https://github.com/alexhopeoconnor/arduino-home-assistant/releases)
+[![](https://img.shields.io/badge/Documentation-40BC13)](docs/README.md)
 
-## Features
+ArduinoHA lets an Arduino, ESP8266, or ESP32 application publish MQTT discovery data that Home Assistant understands. Give it a connected Arduino `Client`, declare entities, and Home Assistant creates the controls and telemetry automatically.
 
-* MQTT discovery (device is added to the Home Assistant panel automatically)
-* Auto reconnect with MQTT broker
+## Start with a sensor
 
-## Examples
+```cpp
+#if defined(ESP8266)
+#include <ESP8266WiFi.h>
+#elif defined(ESP32)
+#include <WiFi.h>
+#endif
+#include <ArduinoHA.h>
 
-* [Binary Sensor](examples/binary-sensor/binary-sensor.ino)
-* [LED switch](examples/led-switch/led-switch.ino)
-* [MQTT with credentials](examples/mqtt-with-credentials/mqtt-with-credentials.ino)
-* [Multi-state button](examples/multi-state-button/multi-state-button.ino)
-* [Sensor (temperature, humidity, etc.)](examples/sensor/sensor.ino)
-* [NodeMCU Wi-Fi](examples/nodemcu/nodemcu.ino)
-* [Arduino Nano 33 IoT Wi-Fi (SAMD)](examples/nano33iot/nano33iot.ino)
-* [Availability feature](examples/availability)
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+HASensorNumber temperature("temperature");
 
-## Tested boards
+void setup() {
+    byte mac[WL_MAC_ADDR_LENGTH];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
 
-* Arduino Uno
-* Arduino Mega
-* Controllino Maxi (standard/pure/automation/power)
-* Controllino Mega (standard/pure)
-* NodeMCU
-* ESP-01
-* Generic ESP8266/ESP8255
-* Arduino Nano 33 IoT (SAMD)
+    // Your application connects Wi-Fi before MQTT begins.
+    temperature.setName("Temperature");
+    temperature.setUnitOfMeasurement("°C");
+    mqtt.begin("mqtt.local", "mqtt_user", "mqtt_password");  // Connection work begins in mqtt.loop().
+}
 
-## Tested Arduino Shields
+void loop() {
+    mqtt.loop();  // Maintains MQTT and publishes discovery after connecting.
+    // Call temperature.setValue(...) when your reading changes.
+}
+```
 
-* Arduino Ethernet Shield (WizNet W5100)
+Build [ESP Sensor](examples/01-esp-sensor/) for a complete ESP8266/ESP32 project. It clearly marks the network and broker values you must provide without committing credentials.
 
-## Supported HA types
+## What you can build
 
-* Binary sensors
-* Device triggers
-* Switches
-* Sensors
-* Tag scanner
+- **Automatic Home Assistant discovery:** retained MQTT discovery messages create entities without hand-written Home Assistant YAML.
+- **Two-way controls:** sensors publish state while switches, lights, covers, and other writable entities receive explicit callbacks.
+- **One physical device:** `HADevice` groups metadata, multiple entities, shared availability, and MQTT Last Will.
+- **Device discovery:** publish one compact discovery document for a new multi-entity device, or keep traditional per-entity discovery.
+- **Small footprint:** exclude entity implementations your firmware does not use.
 
-## Unsupported features
+## Choose an example
 
-The library doesn't support all features of the MQTT integration.
-If you need support for a new feature please open a new issue in the repository.
+| Example | Learn how to… |
+| --- | --- |
+| [ESP Sensor](examples/01-esp-sensor/) | connect an ESP application and publish changing numeric telemetry |
+| [Switch Callback](examples/02-switch-callback/) | reflect Home Assistant commands in a physical output and report state back |
+| [Multi-entity Device](examples/03-multi-entity-device/) | group controls and telemetry with shared availability and Last Will |
+| [Device Discovery](examples/04-device-discovery/) | publish one Home Assistant device-discovery document for a new device |
+| [Entity recipes](examples/README.md#entity-recipes) | find the existing focused Arduino sketches for each supported entity |
 
-# License
+## Install
 
-This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License v3.0 as published by the Free Software Foundation.
+```ini
+lib_deps =
+    home-assistant-integration=https://github.com/alexhopeoconnor/arduino-home-assistant.git#v3.2.1
+```
 
-This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+PlatformIO clones the Git repository and checks out the ref after `#`; that ref is a release tag, not a GitHub Release asset. Arduino IDE is supported through the included [`library.properties`](library.properties).
 
-You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/gpl.html
+See [getting started](docs/getting-started.md), the [documentation map](docs/README.md), [examples](examples/README.md), [release history](CHANGELOG.md), and [licence](LICENSE).

docs/ESP8266-LINKER-WORKAROUND.md

@@ -0,0 +1,32 @@
+# ESP8266 Postmortem linker workaround
+
+The ESP8266 Arduino framework pin used by the DeviceFramework, WiFiManager,
+DFTE, and ArduinoHA maintained builds is intentional:
+
+```ini
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
+```
+
+That upstream commit fixes Postmortem's large-jump failure,
+[`dangerous relocation: j: cannot encode`](https://github.com/esp8266/Arduino/commit/521ae60a89e64bb0d1eb7a0b7addf620ced5cad3).
+It changes the restart wrapper to use a relaxed jump and adds an EPC1 address
+check. The failure is a framework linker/runtime-support issue, not an ArduinoHA
+or application-source error.
+
+ArduinoHA's root `pio test -e esp8266` environment and every guided ESP8266
+PlatformIO example now use this same snapshot. There is no root-test exception
+that can hide a linker regression from the example test harness.
+
+Keep this exact framework snapshot in ESP8266 environments that need the
+maintained test harness. It is unrelated to ESP32, whose pioarduino platform
+selects its framework and compiler as a unit. Do not replace the SHA with a
+version range: remove or advance the pin only after an upstream release includes
+the fix and the affected large firmware has compiled successfully. In
+particular, changing the ESP32 validation lane does not justify changing this
+ESP8266 pin.
+
+The corresponding ESP32 Core 3.3.11 pin is documented in
+[DeviceFramework's toolchain guide](https://github.com/alexhopeoconnor/DeviceFramework/blob/main/docs/TOOLCHAINS.md).
+
+Back to the [documentation map](README.md).

docs/README.md

@@ -0,0 +1,13 @@
+# ArduinoHA documentation
+
+| Topic | What it covers |
+| ----- | ---------------- |
+| [Getting started](getting-started.md) | Connecting a `Client`, installing the library, and the first MQTT lifecycle |
+| [Device & discovery](device-and-discovery.md) | `HADevice`, discovery modes, metadata, identifiers, and migration |
+| [MQTT usage](mqtt-usage.md) | Callbacks, custom topics, availability, logging, and footprint flags |
+| [Entities](entities.md) | Supported Home Assistant entity classes and the best matching example |
+| [ESP8266 linker workaround](ESP8266-LINKER-WORKAROUND.md) | Exact framework pin for the Postmortem large-jump fix |
+| [Examples](../examples/README.md) | Guided PlatformIO projects and focused entity recipes |
+| [Compatibility baseline](compatibility.md) | Supported Home Assistant capabilities and fork-specific compatibility notes |
+
+Class-level API details live in headers under [`src/`](../src/). Return to the [project overview](../README.md).

docs/compatibility.md

@@ -0,0 +1,79 @@
+# Compatibility baseline
+
+This maintenance line begins from fork commit `84cc0037b1c0` (release `v3.0.2`).
+It intentionally tracks Home Assistant's MQTT discovery test harness without merging
+upstream development wholesale.
+
+| Reference | Audited revision / target |
+| --- | --- |
+| Fork baseline | `84cc0037b1c0` (`v3.0.2`) |
+| Upstream main | `1d333ab229b2` (`v2.1.0`) |
+| Upstream develop | `a7039fad810b` (unreleased WIP 2.2.0) |
+| Device discovery minimum | Home Assistant `2024.11.0` |
+| Test harness matrix | `2024.11.3`, current `stable`, current `dev` |
+
+The only imported upstream code fix is the four missing-device-ID guards from
+upstream commit `9c9d074`. Device discovery migration, JSON validation,
+lifecycle handling, and tests are fork-native changes.
+
+## Arduino framework validation lanes
+
+ArduinoHA compiles its embedded test suites and guided PlatformIO examples in
+two maintained lanes:
+
+| Selector | Target | Pinned stack | Role |
+| --- | --- | --- | --- |
+| `esp8266` | ESP8266 D1 mini | Arduino-ESP8266 commit `521ae60` | Maintained Postmortem linker-fix test-harness lane |
+| `esp32` | ESP32 Dev Module | pioarduino `55.03.311` / Arduino-ESP32 3.3.11 / ESP-IDF 5.5.5 | Maintained baseline |
+
+Every lane pins its complete framework stack. The ESP32 runner keeps its
+maintained pioarduino graph in the persistent cache shared by these maintained
+framework repositories, so stale global metadata cannot select an uploader or
+compiler by accident without redownloading matching inputs for every repository.
+The ESP8266 framework pin is independent of the ESP32 baseline; see the [linker
+workaround](ESP8266-LINKER-WORKAROUND.md).
+
+Run the current ESP32 lane locally with:
+
+```bash
+./scripts/test.sh compile --platform esp32
+./scripts/test.sh examples --platform esp32
+```
+
+The script keeps that lane in the persistent PlatformIO Core/cache shared by
+the maintained framework repositories by default
+(`${XDG_CACHE_HOME:-$HOME/.cache}/arduino-framework-platformio/core-3.3.11`).
+This prevents stale global `tool-esptoolpy` metadata from shadowing the current
+pioarduino package-form uploader while avoiding duplicate Core 3.3.11
+downloads. Set `ARDUINOHA_PLATFORMIO_CORE_DIR`,
+`ARDUINOHA_PLATFORMIO_PACKAGES_DIR`, and
+`ARDUINOHA_PLATFORMIO_CACHE_DIR` for a dedicated disk. The script never clears
+that cache or repairs it by overriding one compiler package.
+
+The embedded multi-suite compile path also defaults
+`PLATFORMIO_RUN_JOBS=1`. A caller may explicitly set another value, but the
+serial default avoids a reproducible PlatformIO archive missing-object race
+seen in the Core 3.3.11 lane. Example builds remain parallel.
+
+## Deliberate exclusions
+
+- No merge or wholesale cherry-pick of upstream `develop` / WIP 2.2.0.
+- No `obj_id` serialization: Home Assistant removed that discovery field. Use
+  `setDefaultEntityId()` for new code.
+- No binary-sensor `state_class`: it is not valid in the current HA MQTT binary
+  sensor schema.
+- No upstream IMqttClient abstraction or unreviewed entity-type feature PRs.
+
+## Ongoing audit routine
+
+The `upstream` remote has no usable push URL. Fetch and compare explicitly:
+
+```bash
+git fetch --prune upstream
+git log --oneline main..upstream/develop
+git diff --stat main...upstream/develop
+```
+
+Port only independently reviewed changes with regression tests; treat open
+upstream pull requests as proposals, not release inputs. Run the native,
+board-compile, and HA test harness gates before publishing a new release.

docs/device-and-discovery.md

@@ -0,0 +1,152 @@
+# Device & discovery
+
+## `HADevice`
+
+Represents the physical board in Home Assistant: one device can expose multiple entities (sensors, switches, lights, …).
+
+**Unique ID** (required): must be unique in your Home Assistant instance. Common choices:
+
+- MAC address as bytes: `HADevice device(mac, sizeof(mac));`
+- String: `HADevice device("myId");` — keep it short and alphanumeric.
+- Or default-construct and call `setUniqueId(bytes, length)` in `setup()`.
+
+**Optional metadata** (each costs some RAM/flash; skip on tiny MCUs unless needed):
+
+- `setName`, `setSoftwareVersion`, `setManufacturer`, `setModel`, `setConfigurationUrl`
+- `setModelId`, `setHardwareVersion`, `setSerialNumber`, `setSuggestedArea`, `setViaDevice`
+- `addConnection("mac", "aa:bb:cc:dd:ee:ff")` or `setConnectionsJson("[[\"mac\",\"aa:bb:cc:dd:ee:ff\"]]")`
+
+String setters take **pointers whose contents are not copied** — use literals or storage that outlives the call.
+
+## Discovery
+
+When MQTT connects, the library publishes Home Assistant **MQTT discovery** payloads so entities appear automatically.
+
+Entities can be constructed either before or after `HAMqtt`. Entities which already
+exist when `HAMqtt` is constructed are registered then; entities constructed later
+register immediately. Both the device, MQTT object, and entities must have a lifetime
+that outlasts `mqtt.loop()`.
+
+`HAMqtt` has a configurable entity limit (24 by default). Check
+`getRegisteredDeviceTypeCount()`, `getDeviceTypeLimit()`, and `getDeviceTypeRegistrationFailures()` in firmware diagnostics: registrations above the limit are rejected and logged rather than silently disappearing from discovery.
+
+### Topic prefixes
+
+Defaults:
+
+- Discovery prefix: `homeassistant`
+- Data prefix (states, commands): `aha`
+
+Override before `begin()` if needed:
+
+```cpp
+void configureTopicPrefixes() {
+    // Set both before mqtt.begin(...) publishes any discovery data.
+    mqtt.setDiscoveryPrefix("myHaPrefix");
+    mqtt.setDataPrefix("myDataPrefix");
+}
+```
+
+### Single-component vs device discovery
+
+- **Default:** one retained discovery topic per entity (single-component discovery).
+- **Device discovery:** `HAMqtt::enableDeviceDiscovery()` publishes one retained device payload with components under `cmps`.
+
+Both formats remain supported by Home Assistant. Device discovery requires Home Assistant **2024.11.0 or newer**. Use `enableDeviceDiscovery()` only for a new device which has never published this library's single-component discovery topics.
+
+Choose the mode before connecting a device:
+
+- **New device:** call `enableDeviceDiscovery()` before connecting.
+- **Existing device using single-component discovery:** follow the migration
+  procedure below.
+- **No need for device discovery:** keep the default behavior.
+
+### Migrating an existing device to device discovery
+
+Do not switch an existing device by calling `enableDeviceDiscovery()` alone.
+Home Assistant derives an entity's discovery identity from the topic, and a
+direct switch causes retained-topic conflicts. The migration publishes, in
+order:
+
+1. `{"migrate_discovery":true}` to every old retained component config topic;
+2. the retained `/device/<deviceId>/config` payload; and only then
+3. an empty retained payload to every old component config topic.
+
+Keep the device ID and each entity ID unchanged. They preserve the mapping from the old `<component>/<deviceId>/<entityId>/config` topic to `cmps[entityId]` in the new device payload.
+
+Start migration once during setup, then advance *one stage per loop iteration* after the MQTT connection is available. Each method is retry-safe: do not advance if it returns `false`.
+
+```cpp
+bool migrationStarted = false;
+
+void setup() {
+    // Create device, mqtt, and entities; keep their IDs unchanged.
+    migrationStarted = mqtt.beginDeviceDiscoveryMigration();
+    mqtt.begin("192.168.1.50", "user", "password");
+}
+
+void loop() {
+    mqtt.loop();
+
+    switch (mqtt.getDeviceDiscoveryMigrationState()) {
+    case HAMqtt::DeviceDiscoveryMigrationMarkersPending:
+        mqtt.publishDeviceDiscoveryMigrationMarkers();
+        break;
+    case HAMqtt::DeviceDiscoveryMigrationMarkersPublished:
+        mqtt.publishDeviceDiscoveryMigrationConfig();
+        break;
+    case HAMqtt::DeviceDiscoveryMigrationDevicePublished:
+        mqtt.completeDeviceDiscoveryMigration();
+        break;
+    default:
+        break;
+    }
+}
+```
+
+The migration stage is held in RAM. If the board reboots before completion, start the same migration again; the retained marker/config/cleanup publishes are idempotent. If you must abandon a started migration while connected, call `rollbackDeviceDiscoveryMigration()`. Once a device config has been published, it first writes `{"migrate_discovery":true}` to the device discovery topic, restores the legacy configs, then clears the device config and returns to single-component mode. A failed rollback remains pending and suppresses automatic device-bundle publication until retried successfully. Run all publishing stages from `loop()`, not inside an inbound MQTT callback.
+
+Device discovery can also publish richer origin/device metadata, for example:
+
+```cpp
+void configureDeviceDiscovery() {
+    // These strings are borrowed, so keep literals or other long-lived storage.
+    device.setModelId("esp32-s3-devkit");
+    device.setHardwareVersion("rev-b");
+    device.setSerialNumber("SN-00042");
+    device.setSuggestedArea("Garage");
+    device.setViaDevice("main_gateway");
+    device.addConnection("mac", "AA:BB:CC:DD:EE:FF");
+    mqtt.setOriginSupportUrl("https://example.com/device-help");
+}
+```
+
+For entity identifiers in Home Assistant, prefer **`setDefaultEntityId()`** over legacy **`setObjectId()`**.
+`setObjectId()` remains source-compatible but no longer serializes the removed MQTT `obj_id` property. `setDefaultEntityId()` influences Home Assistant's entity ID only when it first creates the entity; existing users can retain a customized entity ID in the entity registry.
+
+Common entity discovery metadata can be configured on most entity types via:
+
+- `setEnabledByDefault(bool)`
+- `setEntityPicture(const char*)`
+- `setQos(uint8_t)`
+- `setEncoding(const char*)`
+- `setEntityCategory(const char*)`
+
+### Runtime discovery changes
+
+After changing discovery-related settings at runtime:
+
+- `HABaseDeviceType::republishDiscovery()` to refresh discovery.
+- `HABaseDeviceType::removeFromDiscovery()` to remove one entity from discovery.
+
+In single-component mode, removal clears that entity's retained config topic. In device discovery mode, Home Assistant requires a platform-only component marker (`{"p":"sensor"}`, for example), followed by a compacted device bundle that omits the component. ArduinoHA performs both publishes. Call `republishDiscovery()` on that entity to add it back.
+
+## Identifier and lifetime checklist
+
+- Give `HADevice` a stable, non-empty unique ID and each entity a stable, topic-safe ID (`A-Z`, `a-z`, `0-9`, `_`, `-`).
+- Use `enableExtendedUniqueIds()` when multiple devices could otherwise reuse the same entity IDs.
+- Metadata setters store pointers; retain their backing strings. `HAText` copies the current state and command text it receives, so its state does not borrow a transient MQTT buffer.
+
+## Trimming flash (optional)
+
+You can exclude unused entity implementations with macros (see [MQTT usage](mqtt-usage.md#compiler-macros)).

docs/entities.md

@@ -0,0 +1,35 @@
+# Entities
+
+ArduinoHA supports these Home Assistant MQTT discovery entity classes. Choose the focused example where possible; it shows the entity's update or command callback pattern in a runnable sketch.
+
+| Entity | Example |
+| --- | --- |
+| Binary sensor | [binary-sensor](../examples/binary-sensor/binary-sensor.ino) |
+| Button | [button](../examples/button/button.ino) |
+| Camera | [esp32-cam](../examples/esp32-cam/esp32-cam.ino) |
+| Cover | [cover](../examples/cover/cover.ino) |
+| Device tracker | Use the API header; no dedicated sketch yet |
+| Device trigger | [multi-state-button](../examples/multi-state-button/multi-state-button.ino) |
+| Fan | [fan](../examples/fan/fan.ino) |
+| HVAC | [hvac](../examples/hvac/hvac.ino) |
+| Light | [light](../examples/light/light.ino) |
+| Lock | [lock](../examples/lock/lock.ino) |
+| Number | [number](../examples/number/number.ino) |
+| Scene | [scene](../examples/scene/scene.ino) |
+| Select | [select](../examples/select/select.ino) |
+| Sensor | [sensor](../examples/sensor/sensor.ino), [sensor-analog](../examples/sensor-analog/sensor-analog.ino), or [sensor-integer](../examples/sensor-integer/sensor-integer.ino) |
+| Switch | [led-switch](../examples/led-switch/led-switch.ino) or [multi-switch](../examples/multi-switch/multi-switch.ino) |
+| Tag scanner | [tag-scanner](../examples/tag-scanner/tag-scanner.ino) |
+| Text | Use the API header; no dedicated sketch yet |
+
+The library does not currently implement alarm control panels, events,
+humidifiers, images, lawn mowers, sirens, updates, vacuums, valves, or water
+heaters. They cannot be enabled through configuration.
+
+## Common lifecycle
+
+Create long-lived `HADevice`, `HAMqtt`, and entity objects, then call `mqtt.begin(...)` once and `mqtt.loop()` regularly. Entities may be constructed before or after `HAMqtt`; both orders register safely. Read [Getting started](getting-started.md) for the connection flow and [device discovery](device-and-discovery.md) for discovery settings.
+
+For shared online/offline state, use `device.enableSharedAvailability()` and `device.enableLastWill()` before connecting. The [availability examples](../examples/availability/) show the simplest setup, while [advanced availability](../examples/advanced-availability/) covers custom payloads and Last Will behaviour.
+
+Back to the [documentation map](README.md).

docs/getting-started.md

@@ -0,0 +1,107 @@
+# Getting started
+
+## Prerequisites
+
+ArduinoHA talks to Home Assistant over **MQTT** (TCP). You need an MQTT broker reachable from your board. On Home Assistant OS, the [Mosquitto add-on](https://github.com/home-assistant/addons/blob/master/mosquitto/DOCS.md) is a common choice.
+
+## Install the library
+
+**PlatformIO (recommended):** add the maintained release tag in
+`platformio.ini`. Its [`library.json`](../library.json) resolves PubSubClient:
+
+```ini
+lib_deps =
+    home-assistant-integration=https://github.com/alexhopeoconnor/arduino-home-assistant.git#v3.2.1
+```
+
+**Arduino IDE:** this fork is not indexed by Library Manager. Download the
+source archive for a release, extract it, move the extracted library directory
+to `<sketchbook>/libraries/home-assistant-integration`, and restart the IDE.
+
+You also need a network `Client` (Ethernet or Wi-Fi) compatible with the
+Arduino networking API.
+
+## Minimal layout
+
+1. Create **`HADevice`** and **`HAMqtt`** once (global or inside a long-lived object).
+2. Call **`HAMqtt::begin(...)`** once, at the **end** of `setup()` — it only stores broker settings; the actual connection runs during **`HAMqtt::loop()`**.
+3. Call **`mqtt.loop()`** regularly in `loop()` (not necessarily every iteration).
+4. Construct **entity classes** (sensors, switches, …) before or after `HAMqtt`; ArduinoHA registers both orders. Keep all objects alive for the whole MQTT lifetime and configure discovery before the first connection.
+
+### Ethernet (example)
+
+```cpp
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+void setup() {
+    Ethernet.begin(mac);  // Bring up the network Client before MQTT can connect.
+    mqtt.begin("192.168.1.50", "mqtt_user", "mqtt_password");  // Connection begins in mqtt.loop().
+}
+
+void loop() {
+    Ethernet.maintain();  // Renews DHCP leases where the Ethernet library requires it.
+    mqtt.loop();          // Services MQTT connection, discovery, and entity traffic.
+}
+```
+
+### ESP8266 / ESP32 (example)
+
+```cpp
+#if defined(ESP8266)
+#include <ESP8266WiFi.h>
+#elif defined(ESP32)
+#include <WiFi.h>
+#endif
+#include <ArduinoHA.h>
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+
+void setup() {
+    byte mac[WL_MAC_ADDR_LENGTH];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+
+    WiFi.begin("SSID", "password");
+    // Keep this blocking wait only in a minimal sketch. Production firmware
+    // should retry, time out, or hand control to its provisioning flow.
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(500);
+    }
+
+    // begin() stores broker settings; mqtt.loop() performs connection and recovery.
+    mqtt.begin("192.168.1.50", "mqtt_user", "mqtt_password");
+}
+
+void loop() {
+    mqtt.loop();  // Service reconnects, subscriptions, and discovery publishing.
+}
+```
+
+## `begin()` variants
+
+All are valid; pick one. Hostnames work instead of IP addresses.
+
+- `mqtt.begin("192.168.1.50")` — anonymous, port 1883  
+- `mqtt.begin("192.168.1.50", 8888)` — anonymous, custom port  
+- `mqtt.begin("192.168.1.50", "user", "pass")` — credentials, port 1883  
+- `mqtt.begin("192.168.1.50", 8888, "user", "pass")` — credentials + custom port  
+
+`begin()` is intentionally a one-time configuration call. Reconnects are owned by `mqtt.loop()`, which uses the configured reconnect interval. Do not call `begin()` in a reconnect timer. `mqtt.disconnect()` now also produces the registered disconnected and state-change callbacks, making an explicit shutdown observable in the same way as a transport loss.
+
+Use Home Assistant **2024.11.0 or newer** when opting into device discovery. See [Device & discovery](device-and-discovery.md) for the required staged migration from an existing single-component device.
+
+## Security note
+
+Credentials go over **plain TCP** unless you use a TLS-capable stack and broker setup. On a trusted LAN this is often acceptable; treat untrusted networks accordingly.
+
+## Examples
+
+See [`examples/`](../examples/) — start with `nodemcu` / `nano33iot` or an entity example matching what you need.

docs/mqtt-usage.md

@@ -0,0 +1,185 @@
+# MQTT usage
+
+## Callbacks and tuning
+
+The following snippets extend a sketch that already owns long-lived `HADevice`, `HAMqtt`, and entity objects. Configure callbacks, discovery metadata, and availability before `mqtt.begin(...)`; call the publishing snippets later from normal application logic.
+
+`HAMqtt` supports optional callbacks and PubSubClient tuning:
+
+```cpp
+// These callbacks are registered before mqtt.begin(...).
+void onMessage(const char* topic, const uint8_t* payload, uint16_t length) { /* ... */ }
+void onConnected() { /* ... */ }
+void onDisconnected() { /* ... */ }
+void onStateChanged(HAMqtt::ConnectionState state) { /* ... */ }
+
+void setup() {
+    // A successful reconnect creates a new MQTT session, so onConnected runs again.
+    mqtt.onMessage(onMessage);
+    mqtt.onConnected(onConnected);
+    mqtt.onDisconnected(onDisconnected);
+    mqtt.onStateChanged(onStateChanged);
+    mqtt.setBufferSize(512);   // Increase only when a larger MQTT packet is required.
+    mqtt.setKeepAlive(60);     // Seconds; the default is 15.
+    mqtt.begin("192.168.1.50", "user", "pass");
+}
+```
+
+## Custom subscriptions
+
+Subscribe after each successful connection (for example in `onConnected`), because subscriptions are tied to the MQTT session:
+
+```cpp
+void onConnected() {
+    // MQTT subscriptions belong to this session and must be restored after reconnecting.
+    mqtt.subscribe("my/custom/topic");
+}
+```
+
+Handle payloads in `onMessage`.
+
+## Publishing arbitrary payloads
+
+```cpp
+// Call after mqtt.begin(...); retain controls whether the broker keeps this value.
+void publishApplicationState() {
+    mqtt.publish("customTopic", "payload", false);  // Not retained.
+    mqtt.publish("customTopic", "payload", true);   // Retained.
+}
+```
+
+## Availability
+
+**Shared availability (recommended):** one availability topic for the whole device — works well with **Last Will** (LWT):
+
+```cpp
+// Configure device-wide availability before mqtt.begin(...).
+void configureSharedAvailability() {
+    device.enableSharedAvailability();
+    device.setPayloadAvailable("up");
+    device.setPayloadNotAvailable("down");
+    device.enableLastWill();   // Broker publishes offline when TCP drops.
+    // device.setAvailability(false);  // Optional: start as offline.
+}
+```
+
+**Per-entity availability:** call `someEntity.setAvailability(true/false)` on each type. Does not use LWT the same way as shared mode; see examples under `examples/availability/`.
+
+Custom per-entity payloads are supported:
+
+```cpp
+// Configure the relevant entity before mqtt.begin(...).
+void configureSensorAvailability() {
+    sensor.setPayloadAvailable("ready");
+    sensor.setPayloadNotAvailable("lost");
+}
+```
+
+For multi-topic availability discovery, add full MQTT topics and a mode:
+
+```cpp
+// `sensor` is the entity whose availability depends on these external topics.
+void configureExternalAvailability() {
+    sensor.setAvailabilityMode("all");
+    sensor.addAvailabilityEntry("bridge/status");
+    sensor.addAvailabilityEntry("sensor/status", "{{ value_json.state }}");
+}
+```
+
+## Discovery helpers by entity
+
+Common entity discovery metadata is available on most entity classes:
+
+```cpp
+// `entity` is an entity type that supports these common discovery fields.
+void configureCommonDiscovery(HABaseDeviceType& entity) {
+    entity.setEnabledByDefault(false);
+    entity.setEntityPicture("https://example.com/entity.png");
+    entity.setQos(1);
+    entity.setEncoding("utf-8");
+    entity.setEntityCategory("diagnostic");
+}
+```
+
+Read-only sensor presentation/template helpers:
+
+```cpp
+// `sensor` is a read-only HASensor instance.
+void configureSensorPresentation(HASensor& sensor) {
+    sensor.setSuggestedDisplayPrecision(2);
+    sensor.setValueTemplate("{{ value_json.temperature }}");
+    sensor.setJsonAttributesTemplate("{{ value_json.attrs | tojson }}");
+    sensor.setLastResetValueTemplate("{{ value_json.last_reset }}");
+    sensor.setDeviceClass("enum");
+    sensor.setOptions("idle;charging;discharging;fault");
+}
+```
+
+Writable entity template/payload helpers:
+
+```cpp
+// These names refer to the matching writable entity instances in the application.
+void configureWritableEntities(HASwitch& mySwitch,
+                               HANumber& myNumber,
+                               HASelect& mySelect,
+                               HAText& myText,
+                               HAButton& myButton) {
+    mySwitch.setPayloadOn("ENABLE");
+    mySwitch.setPayloadOff("DISABLE");
+    mySwitch.setStateOn("running");
+    mySwitch.setStateOff("stopped");
+    mySwitch.setValueTemplate("{{ value_json.state }}");
+    mySwitch.setCommandTemplate("{{ value_json.command }}");
+
+    myNumber.setPayloadReset("RESET");
+    myNumber.setCommandTemplate("{{ value | float | round(1) }}");
+
+    mySelect.setCommandTemplate("{{ value_json.choice }}");
+    myText.setCommandTemplate("{{ value_json.text }}");
+    myButton.setPayloadPress("PRESS");
+}
+```
+
+## Compiler macros
+
+Defined in `ArduinoHADefines.h` or via build flags.
+
+- **`ARDUINOHA_DISABLE_STDFUNCTION`** — disables the default capturing-lambda and
+  `std::bind` overloads on entity command APIs. Use it on targets without a complete
+  `std::function` implementation or where code size/RAM matters (constrained AVR
+  builds are the usual case). ESP8266/ESP32 support the overloads. `HAMqtt`
+  lifecycle callbacks remain ordinary function pointers.
+- **`ARDUINOHA_DEBUG`** — enables ArduinoHA logging by default and sets the initial maximum verbosity to `Debug`. Without this flag, structured logs are compiled in but remain disabled until you call `arduinoHASetLogEnabled(true)`.
+
+Structured logging is available through a long-lived sink:
+
+```cpp
+class MyLogSink : public ArduinoHALogSink {
+public:
+    void log(const ArduinoHALogMessage& msg) override {
+        Serial.print("[");
+        Serial.print(arduinoHALogLevelTag(msg.level));
+        Serial.print("][aha.");
+        Serial.print(msg.subsystem);
+        Serial.print("] ");
+        Serial.println(msg.text);
+    }
+};
+
+MyLogSink logSink;  // The installed sink must outlive ArduinoHA logging.
+
+void setup() {
+    Serial.begin(115200);
+    arduinoHASetLogSink(&logSink);
+    arduinoHASetLogEnabled(true);
+    arduinoHASetLogLevel(ArduinoHALogLevel::Trace);
+}
+```
+
+`arduinoHALog(...)` and `arduinoHALogf(...)` support subsystem-tagged messages such as `mqtt`, `discovery`, `availability`, `serializer`, `entity`, and `device`. Install a sink when you want those messages to join your application’s normal serial or structured log stream.
+
+Applications that use Wi-Fi can register **`arduinoHASetNetworkStatusFn`** with a callback returning `WiFi.status()`. Publish failure diagnostics can then include the current Wi-Fi status without coupling ArduinoHA to a particular network library.
+
+**Exclude unused device types** (saves flash from vtables), e.g.:
+
+`EX_ARDUINOHA_BINARY_SENSOR`, `EX_ARDUINOHA_BUTTON`, `EX_ARDUINOHA_CAMERA`, `EX_ARDUINOHA_COVER`, `EX_ARDUINOHA_DEVICE_TRACKER`, `EX_ARDUINOHA_DEVICE_TRIGGER`, `EX_ARDUINOHA_FAN`, `EX_ARDUINOHA_HVAC`, `EX_ARDUINOHA_LIGHT`, `EX_ARDUINOHA_LOCK`, `EX_ARDUINOHA_NUMBER`, `EX_ARDUINOHA_SCENE`, `EX_ARDUINOHA_SELECT`, `EX_ARDUINOHA_SENSOR`, `EX_ARDUINOHA_SWITCH`, `EX_ARDUINOHA_TAG_SCANNER`

examples/01-esp-sensor/README.md

@@ -0,0 +1,9 @@
+# ESP Sensor
+
+This is the first complete ArduinoHA project for an ESP8266 D1 mini or ESP32 development board. It connects Wi-Fi, derives a stable device ID from the board MAC address, and publishes a changing **Uptime** sensor to Home Assistant.
+
+Before uploading, replace the `EXAMPLE_*` values in `include/ExampleNetwork.h`, or provide them as PlatformIO build flags. The header contains safe placeholders and must not contain real credentials when committed.
+
+After MQTT connects, Home Assistant discovers **ArduinoHA sensor example** and its Uptime entity. Rebooting the board keeps the same Home Assistant identity because its MAC address is stable.
+
+See [getting started](../../docs/getting-started.md) and the shared [examples guide](../README.md).

examples/01-esp-sensor/include/ExampleNetwork.h

@@ -0,0 +1,37 @@
+#pragma once
+#if defined(ESP32)
+#include <Network.h>
+#include <WiFi.h>
+#else
+#include <ESP8266WiFi.h>
+#endif
+
+#ifndef EXAMPLE_WIFI_SSID
+#define EXAMPLE_WIFI_SSID "replace-with-wifi-name"
+#endif
+#ifndef EXAMPLE_WIFI_PASSWORD
+#define EXAMPLE_WIFI_PASSWORD "replace-with-wifi-password"
+#endif
+#ifndef EXAMPLE_MQTT_HOST
+#define EXAMPLE_MQTT_HOST "replace-with-mqtt-host"
+#endif
+#ifndef EXAMPLE_MQTT_USER
+#define EXAMPLE_MQTT_USER ""
+#endif
+#ifndef EXAMPLE_MQTT_PASSWORD
+#define EXAMPLE_MQTT_PASSWORD ""
+#endif
+
+inline void connectExampleWiFi() {
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(EXAMPLE_WIFI_SSID, EXAMPLE_WIFI_PASSWORD);
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(250);
+    }
+}
+
+inline void setExampleUniqueId(HADevice& device) {
+    uint8_t mac[6];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+}

examples/01-esp-sensor/platformio.ini

@@ -0,0 +1,24 @@
+[platformio]
+default_envs = esp8266
+
+[common]
+framework = arduino
+lib_ldf_mode = deep+
+lib_deps =
+    home-assistant-integration=symlink://../..
+
+[env:esp8266]
+extends = common
+platform = espressif8266
+board = d1_mini
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
+
+[env:esp32]
+extends = common
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.311/platform-espressif32.zip
+board = esp32dev
+build_unflags = -std=gnu++11
+build_flags =
+    -std=gnu++14
+    -I${platformio.packages_dir}/framework-arduinoespressif32/libraries/Network/src

examples/01-esp-sensor/src/main.cpp

@@ -0,0 +1,30 @@
+#include <Arduino.h>
+#include <ArduinoHA.h>
+#include "ExampleNetwork.h"
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+HASensorNumber uptime("uptime");
+
+void setup() {
+    Serial.begin(115200);
+    connectExampleWiFi();
+    setExampleUniqueId(device);
+
+    device.setName("ArduinoHA sensor example");
+    device.setSoftwareVersion("1.0.0");
+    uptime.setName("Uptime");
+    uptime.setUnitOfMeasurement("s");
+    mqtt.begin(EXAMPLE_MQTT_HOST, EXAMPLE_MQTT_USER, EXAMPLE_MQTT_PASSWORD);
+}
+
+void loop() {
+    mqtt.loop();
+
+    static unsigned long lastUpdate = 0;
+    if (millis() - lastUpdate >= 1000) {
+        uptime.setValue(static_cast<uint32_t>(millis() / 1000));
+        lastUpdate = millis();
+    }
+}

examples/02-switch-callback/README.md

@@ -0,0 +1,9 @@
+# Switch Callback
+
+This example creates one writable Home Assistant switch. When Home Assistant sends a command, `onOutputCommand()` changes the local output and immediately reports the resulting state back through the supplied `HASwitch`.
+
+The ESP8266 build uses `LED_BUILTIN`; the ESP32 build uses GPIO 2. Confirm your board’s LED polarity before treating that output as a real load.
+
+Set the Wi-Fi and MQTT placeholders in `include/ExampleNetwork.h`, flash the board, then toggle **Example output** in Home Assistant.
+
+See [MQTT usage](../../docs/mqtt-usage.md) and the shared [examples guide](../README.md).

examples/02-switch-callback/include/ExampleNetwork.h

@@ -0,0 +1,37 @@
+#pragma once
+#if defined(ESP32)
+#include <Network.h>
+#include <WiFi.h>
+#else
+#include <ESP8266WiFi.h>
+#endif
+
+#ifndef EXAMPLE_WIFI_SSID
+#define EXAMPLE_WIFI_SSID "replace-with-wifi-name"
+#endif
+#ifndef EXAMPLE_WIFI_PASSWORD
+#define EXAMPLE_WIFI_PASSWORD "replace-with-wifi-password"
+#endif
+#ifndef EXAMPLE_MQTT_HOST
+#define EXAMPLE_MQTT_HOST "replace-with-mqtt-host"
+#endif
+#ifndef EXAMPLE_MQTT_USER
+#define EXAMPLE_MQTT_USER ""
+#endif
+#ifndef EXAMPLE_MQTT_PASSWORD
+#define EXAMPLE_MQTT_PASSWORD ""
+#endif
+
+inline void connectExampleWiFi() {
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(EXAMPLE_WIFI_SSID, EXAMPLE_WIFI_PASSWORD);
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(250);
+    }
+}
+
+inline void setExampleUniqueId(HADevice& device) {
+    uint8_t mac[6];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+}

examples/02-switch-callback/platformio.ini

@@ -0,0 +1,24 @@
+[platformio]
+default_envs = esp8266
+
+[common]
+framework = arduino
+lib_ldf_mode = deep+
+lib_deps =
+    home-assistant-integration=symlink://../..
+
+[env:esp8266]
+extends = common
+platform = espressif8266
+board = d1_mini
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
+
+[env:esp32]
+extends = common
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.311/platform-espressif32.zip
+board = esp32dev
+build_unflags = -std=gnu++11
+build_flags =
+    -std=gnu++14
+    -I${platformio.packages_dir}/framework-arduinoespressif32/libraries/Network/src

examples/02-switch-callback/src/main.cpp

@@ -0,0 +1,36 @@
+#include <Arduino.h>
+#include <ArduinoHA.h>
+#include "ExampleNetwork.h"
+
+#if defined(ESP32)
+constexpr uint8_t kOutputPin = 2;
+#else
+constexpr uint8_t kOutputPin = LED_BUILTIN;
+#endif
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+HASwitch output("output");
+
+void onOutputCommand(bool state, HASwitch* sender) {
+    digitalWrite(kOutputPin, state ? HIGH : LOW);
+    sender->setState(state);
+}
+
+void setup() {
+    Serial.begin(115200);
+    pinMode(kOutputPin, OUTPUT);
+    digitalWrite(kOutputPin, LOW);
+    connectExampleWiFi();
+    setExampleUniqueId(device);
+
+    device.setName("ArduinoHA switch example");
+    output.setName("Example output");
+    output.onCommand(onOutputCommand);
+    mqtt.begin(EXAMPLE_MQTT_HOST, EXAMPLE_MQTT_USER, EXAMPLE_MQTT_PASSWORD);
+}
+
+void loop() {
+    mqtt.loop();
+}

examples/03-multi-entity-device/README.md

@@ -0,0 +1,9 @@
+# Multi-entity Device
+
+This example groups an Uptime sensor and writable output under one `HADevice`. It adds common metadata, one shared availability topic, and MQTT Last Will so Home Assistant marks the complete device unavailable if its network connection disappears.
+
+Configure `include/ExampleNetwork.h`, flash the selected target, and inspect the device page in Home Assistant. Both entities belong to **ArduinoHA multi-entity example** and share its availability state.
+
+Use this shape when one physical board exposes several related controls or sensors.
+
+See [device and discovery](../../docs/device-and-discovery.md) and [MQTT usage](../../docs/mqtt-usage.md).

examples/03-multi-entity-device/include/ExampleNetwork.h

@@ -0,0 +1,37 @@
+#pragma once
+#if defined(ESP32)
+#include <Network.h>
+#include <WiFi.h>
+#else
+#include <ESP8266WiFi.h>
+#endif
+
+#ifndef EXAMPLE_WIFI_SSID
+#define EXAMPLE_WIFI_SSID "replace-with-wifi-name"
+#endif
+#ifndef EXAMPLE_WIFI_PASSWORD
+#define EXAMPLE_WIFI_PASSWORD "replace-with-wifi-password"
+#endif
+#ifndef EXAMPLE_MQTT_HOST
+#define EXAMPLE_MQTT_HOST "replace-with-mqtt-host"
+#endif
+#ifndef EXAMPLE_MQTT_USER
+#define EXAMPLE_MQTT_USER ""
+#endif
+#ifndef EXAMPLE_MQTT_PASSWORD
+#define EXAMPLE_MQTT_PASSWORD ""
+#endif
+
+inline void connectExampleWiFi() {
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(EXAMPLE_WIFI_SSID, EXAMPLE_WIFI_PASSWORD);
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(250);
+    }
+}
+
+inline void setExampleUniqueId(HADevice& device) {
+    uint8_t mac[6];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+}

examples/03-multi-entity-device/platformio.ini

@@ -0,0 +1,24 @@
+[platformio]
+default_envs = esp8266
+
+[common]
+framework = arduino
+lib_ldf_mode = deep+
+lib_deps =
+    home-assistant-integration=symlink://../..
+
+[env:esp8266]
+extends = common
+platform = espressif8266
+board = d1_mini
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
+
+[env:esp32]
+extends = common
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.311/platform-espressif32.zip
+board = esp32dev
+build_unflags = -std=gnu++11
+build_flags =
+    -std=gnu++14
+    -I${platformio.packages_dir}/framework-arduinoespressif32/libraries/Network/src

examples/03-multi-entity-device/src/main.cpp

@@ -0,0 +1,48 @@
+#include <Arduino.h>
+#include <ArduinoHA.h>
+#include "ExampleNetwork.h"
+
+#if defined(ESP32)
+constexpr uint8_t kOutputPin = 2;
+#else
+constexpr uint8_t kOutputPin = LED_BUILTIN;
+#endif
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+HASensorNumber uptime("uptime");
+HASwitch output("output");
+
+void onOutputCommand(bool state, HASwitch* sender) {
+    digitalWrite(kOutputPin, state ? HIGH : LOW);
+    sender->setState(state);
+}
+
+void setup() {
+    Serial.begin(115200);
+    pinMode(kOutputPin, OUTPUT);
+    connectExampleWiFi();
+    setExampleUniqueId(device);
+
+    device.setName("ArduinoHA multi-entity example");
+    device.setManufacturer("Example Devices");
+    device.setSoftwareVersion("1.0.0");
+    device.enableSharedAvailability();
+    device.enableLastWill();
+
+    uptime.setName("Uptime");
+    uptime.setUnitOfMeasurement("s");
+    output.setName("Example output");
+    output.onCommand(onOutputCommand);
+    mqtt.begin(EXAMPLE_MQTT_HOST, EXAMPLE_MQTT_USER, EXAMPLE_MQTT_PASSWORD);
+}
+
+void loop() {
+    mqtt.loop();
+    static unsigned long lastUpdate = 0;
+    if (millis() - lastUpdate >= 1000) {
+        uptime.setValue(static_cast<uint32_t>(millis() / 1000));
+        lastUpdate = millis();
+    }
+}

examples/04-device-discovery/README.md

@@ -0,0 +1,9 @@
+# Device Discovery
+
+This example opts into Home Assistant MQTT device discovery. Instead of one retained discovery document per entity, ArduinoHA publishes one device document containing the component definitions and richer board metadata.
+
+Use device discovery for a **new** device on Home Assistant 2024.11.0 or newer. Do not enable it on a device that has already published traditional single-component discovery without following the documented migration procedure.
+
+After configuring `include/ExampleNetwork.h` and flashing the board, Home Assistant discovers **ArduinoHA device discovery example** and its Uptime sensor.
+
+See [device discovery](../../docs/device-and-discovery.md#single-component-vs-device-discovery) and the shared [examples guide](../README.md).

examples/04-device-discovery/include/ExampleNetwork.h

@@ -0,0 +1,37 @@
+#pragma once
+#if defined(ESP32)
+#include <Network.h>
+#include <WiFi.h>
+#else
+#include <ESP8266WiFi.h>
+#endif
+
+#ifndef EXAMPLE_WIFI_SSID
+#define EXAMPLE_WIFI_SSID "replace-with-wifi-name"
+#endif
+#ifndef EXAMPLE_WIFI_PASSWORD
+#define EXAMPLE_WIFI_PASSWORD "replace-with-wifi-password"
+#endif
+#ifndef EXAMPLE_MQTT_HOST
+#define EXAMPLE_MQTT_HOST "replace-with-mqtt-host"
+#endif
+#ifndef EXAMPLE_MQTT_USER
+#define EXAMPLE_MQTT_USER ""
+#endif
+#ifndef EXAMPLE_MQTT_PASSWORD
+#define EXAMPLE_MQTT_PASSWORD ""
+#endif
+
+inline void connectExampleWiFi() {
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(EXAMPLE_WIFI_SSID, EXAMPLE_WIFI_PASSWORD);
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(250);
+    }
+}
+
+inline void setExampleUniqueId(HADevice& device) {
+    uint8_t mac[6];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+}

examples/04-device-discovery/platformio.ini

@@ -0,0 +1,24 @@
+[platformio]
+default_envs = esp8266
+
+[common]
+framework = arduino
+lib_ldf_mode = deep+
+lib_deps =
+    home-assistant-integration=symlink://../..
+
+[env:esp8266]
+extends = common
+platform = espressif8266
+board = d1_mini
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
+
+[env:esp32]
+extends = common
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.311/platform-espressif32.zip
+board = esp32dev
+build_unflags = -std=gnu++11
+build_flags =
+    -std=gnu++14
+    -I${platformio.packages_dir}/framework-arduinoespressif32/libraries/Network/src

examples/04-device-discovery/src/main.cpp

@@ -0,0 +1,33 @@
+#include <Arduino.h>
+#include <ArduinoHA.h>
+#include "ExampleNetwork.h"
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+HASensorNumber uptime("uptime");
+
+void setup() {
+    Serial.begin(115200);
+    connectExampleWiFi();
+    setExampleUniqueId(device);
+
+    device.setName("ArduinoHA device discovery example");
+    device.setManufacturer("Example Devices");
+    device.setModel("ESP example");
+    device.setSoftwareVersion("1.0.0");
+    uptime.setName("Uptime");
+    uptime.setUnitOfMeasurement("s");
+
+    mqtt.enableDeviceDiscovery();
+    mqtt.begin(EXAMPLE_MQTT_HOST, EXAMPLE_MQTT_USER, EXAMPLE_MQTT_PASSWORD);
+}
+
+void loop() {
+    mqtt.loop();
+    static unsigned long lastUpdate = 0;
+    if (millis() - lastUpdate >= 1000) {
+        uptime.setValue(static_cast<uint32_t>(millis() / 1000));
+        lastUpdate = millis();
+    }
+}

examples/README.md

@@ -0,0 +1,45 @@
+# ArduinoHA examples
+
+Start with a guided PlatformIO project when you are new to the library. Each one builds for ESP8266 and ESP32, contains safe placeholder credentials, and explains the Home Assistant result you should see.
+
+```bash
+pio run -d examples/01-esp-sensor -e esp8266
+pio run -d examples/01-esp-sensor -e esp8266 -t upload
+```
+
+The checked-in `esp32` environment uses Arduino-ESP32 3.3.11. A consuming
+application should choose and pin its complete PlatformIO platform stack.
+
+| Guided example | What it demonstrates |
+| --- | --- |
+| [ESP Sensor](01-esp-sensor/) | Wi-Fi application wiring, a unique device ID, and changing numeric telemetry |
+| [Switch Callback](02-switch-callback/) | A Home Assistant command callback and local state acknowledgement |
+| [Multi-entity Device](03-multi-entity-device/) | Multiple entities, shared availability, and MQTT Last Will |
+| [Device Discovery](04-device-discovery/) | One device-discovery document for a newly deployed device |
+
+## Entity recipes
+
+The original focused sketches remain useful as short API recipes. They are intentionally transport-specific Arduino sketches, rather than full product firmware.
+
+| Recipe | Home Assistant behaviour |
+| --- | --- |
+| [binary-sensor](binary-sensor/binary-sensor.ino) | Door/contact-style binary state |
+| [button](button/button.ino) | Press action |
+| [cover](cover/cover.ino) | Open, close, and stop commands |
+| [esp32-cam](esp32-cam/esp32-cam.ino) | ESP32 camera preview |
+| [fan](fan/fan.ino) | State and speed commands |
+| [hvac](hvac/hvac.ino) | Modes, power, and target temperature |
+| [led-switch](led-switch/led-switch.ino) | Basic writable switch |
+| [light](light/light.ino) | Brightness, colour temperature, and RGB |
+| [lock](lock/lock.ino) | Writable lock state |
+| [multi-state-button](multi-state-button/multi-state-button.ino) | Device triggers from a wall switch |
+| [multi-switch](multi-switch/multi-switch.ino) | Multiple writable switches |
+| [number](number/number.ino) | Writable numeric value |
+| [scene](scene/scene.ino) | Scene trigger |
+| [select](select/select.ino) | Writable option list |
+| [sensor](sensor/sensor.ino) | String state sensor |
+| [sensor-analog](sensor-analog/sensor-analog.ino) | Analog voltage measurement |
+| [sensor-integer](sensor-integer/sensor-integer.ino) | Integer uptime measurement |
+| [tag-scanner](tag-scanner/tag-scanner.ino) | RFID tag reporting |
+
+See the [entity guide](../docs/entities.md) and [project overview](../README.md).

examples/advanced-availability/advanced-availability.ino

@@ -0,0 +1,75 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define INPUT_PIN       9
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+unsigned long lastReadAt = millis();
+unsigned long lastAvailabilityToggleAt = millis();
+bool lastInputState = false;
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// "myInput" is unique ID of the sensor. You should define you own ID.
+HABinarySensor sensor("myInput");
+
+void setup() {
+    pinMode(INPUT_PIN, INPUT_PULLUP);
+    lastInputState = digitalRead(INPUT_PIN);
+
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    lastReadAt = millis();
+    lastAvailabilityToggleAt = millis();
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+    mqtt.setOriginSupportUrl("https://example.com/device-help");
+
+    sensor.setCurrentState(lastInputState); // optional
+    sensor.setName("Door sensor"); // optional
+    sensor.setDeviceClass("door"); // optional
+    sensor.setPayloadAvailable("ready");
+    sensor.setPayloadNotAvailable("lost");
+
+    // Optional multi-topic discovery metadata for external health sources.
+    // Runtime availability publishing still uses sensor.setAvailability(...).
+    // sensor.setAvailabilityMode("all");
+    // sensor.addAvailabilityEntry("bridge/status");
+    // sensor.addAvailabilityEntry("sensor/health", "{{ value_json.state }}");
+
+    // This method enables availability for all device types registered on the device.
+    // For example, if you have 5 sensors on the same device, you can enable
+    // shared availability and change availability state of all sensors using
+    // single method call "device.setAvailability(false|true)"
+    device.enableSharedAvailability();
+
+    // Optionally, you can enable MQTT LWT feature. If device will lose connection
+    // to the broker, all device types related to it will be marked as offline in
+    // the Home Assistant Panel.
+    device.enableLastWill();
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    if ((millis() - lastReadAt) > 30) { // read in 30ms interval
+        // library produces MQTT message if a new state is different than the previous one
+        sensor.setState(digitalRead(INPUT_PIN));
+        lastInputState = sensor.getCurrentState();
+        lastReadAt = millis();
+    }
+
+    if ((millis() - lastAvailabilityToggleAt) > 5000) {
+        device.setAvailability(!device.isAvailable());
+        lastAvailabilityToggleAt = millis();
+    }
+}

examples/availability/README.md

@@ -1,31 +0,0 @@
-# Home Assistant availability example
-
-This example shows how to use "availability" feature of the Home Assistant.
-It's supported only by following device types:
-* Binary sensor
-* Sensor
-* Switch
-
-## Initialization and usage
-
-Availability feature is turned off by default. In order to turn it on for the specific
-sensor/switch you need to set initial state of the unit by calling `setAvailability` method.
-
-Example:
-```cpp
-...
-HABinarySensor sensor("input", "door", true, mqtt);
-
-void setup() {
-    // ...
-
-    // method must be called before `mqtt.begin(...)`
-    sensor.setAvailability(false); // offline
-
-    mqtt.begin(BROKER_ADDR);
-}
-...
-```
-
-After availability is set for the very first time you can call `setAvailability` in any time.
-Each time the method is called, the device will publish MQTT message to the broker.

examples/availability/availability.ino

@@ -13,10 +13,8 @@ EthernetClient client;
 HADevice device(mac, sizeof(mac));
 HAMqtt mqtt(client, device);
 
-// "input" may be anything you want to be displayed in HA panel
-// "door" is device class (based on the class HA displays different icons in the panel)
-// "true" is initial state of the sensor. In this example it's "true" as we use pullup resistor
-HABinarySensor sensor("input", "door", true, mqtt);
+// "myInput" is unique ID of the sensor. You should define you own ID.
+HABinarySensor sensor("myInput");
 
 void setup() {
     pinMode(INPUT_PIN, INPUT_PULLUP);
@@ -26,6 +24,7 @@ void setup() {
     Ethernet.begin(mac);
 
     // turn on "availability" feature
+    // this method also sets initial availability so you can use "true" or "false"
     sensor.setAvailability(false);
 
     lastReadAt = millis();
@@ -35,6 +34,10 @@ void setup() {
     device.setName("Arduino");
     device.setSoftwareVersion("1.0.0");
 
+    sensor.setCurrentState(lastInputState); // optional
+    sensor.setName("Door sensor"); // optional
+    sensor.setDeviceClass("door"); // optional
+
     mqtt.begin(BROKER_ADDR);
 }
 
@@ -45,7 +48,7 @@ void loop() {
     if ((millis() - lastReadAt) > 30) { // read in 30ms interval
         // library produces MQTT message if a new state is different than the previous one
         sensor.setState(digitalRead(INPUT_PIN));
-        lastInputState = sensor.getState();
+        lastInputState = sensor.getCurrentState();
         lastReadAt = millis();
     }
 

examples/binary-sensor/binary-sensor.ino

@@ -12,10 +12,8 @@ EthernetClient client;
 HADevice device(mac, sizeof(mac));
 HAMqtt mqtt(client, device);
 
-// "input" may be anything you want to be displayed in HA panel
-// "door" is device class (based on the class HA displays different icons in the panel)
-// "true" is initial state of the sensor. In this example it's "true" as we use pullup resistor
-HABinarySensor sensor("input", "door", true, mqtt);
+// "myInput" is unique ID of the sensor. You should define you own ID.
+HABinarySensor sensor("myInput");
 
 void setup() {
     pinMode(INPUT_PIN, INPUT_PULLUP);
@@ -24,10 +22,16 @@ void setup() {
     // you don't need to verify return status
     Ethernet.begin(mac);
 
-    // set device's details (optional)
+    // optional device's details
     device.setName("Arduino");
     device.setSoftwareVersion("1.0.0");
 
+    // optional properties
+    sensor.setCurrentState(lastInputState);
+    sensor.setName("Door sensor");
+    sensor.setDeviceClass("door");
+    sensor.setIcon("mdi:fire");
+
     mqtt.begin(BROKER_ADDR);
 }
 
@@ -35,10 +39,11 @@ void loop() {
     Ethernet.maintain();
     mqtt.loop();
 
+    // reading the digital input of the Arduino device
     if ((millis() - lastReadAt) > 30) { // read in 30ms interval
         // library produces MQTT message if a new state is different than the previous one
         sensor.setState(digitalRead(INPUT_PIN));
-        lastInputState = sensor.getState();
+        lastInputState = sensor.getCurrentState();
         lastReadAt = millis();
     }
 }

examples/button/button.ino

@@ -0,0 +1,51 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// "myButtonA" and "myButtonB" are unique IDs of buttons. You should define you own ID.
+HAButton buttonA("myButtonA");
+HAButton buttonB("myButtonB");
+
+void onButtonCommand(HAButton* sender)
+{
+    if (sender == &buttonA) {
+        // button A was clicked, do your logic here
+    } else if (sender == &buttonB) {
+        // button B was clicked, do your logic here
+    }
+}
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // optional device's details
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // optional properties
+    buttonA.setIcon("mdi:fire");
+    buttonA.setName("Click me A");
+    // buttonA.setPayloadPress("PRESS_A");
+    // buttonA.setCommandTemplate("{{ value_json.command }}");
+    buttonB.setIcon("mdi:home");
+    buttonB.setName("Click me B");
+
+    // press callbacks
+    buttonA.onCommand(onButtonCommand);
+    buttonB.onCommand(onButtonCommand);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+}

examples/cover/cover.ino

@@ -0,0 +1,70 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// "myCover" is unique ID of the cover. You should define your own ID.
+HACover cover("myCover", HACover::PositionFeature);
+
+// PositionFeature is optional, however required to be in a "stopped" state other than open or closed.
+// If ommitted, a CommandStop will result in HA treating the cover as either Open or Closed immediately after the command.
+// See https://www.home-assistant.io/integrations/cover.mqtt/
+// Added in https://github.com/dawidchyrzynski/arduino-home-assistant/pull/111
+
+void onCoverCommand(HACover::CoverCommand cmd, HACover* sender) {
+    if (cmd == HACover::CommandOpen) {
+        Serial.println("Command: Open");
+        sender->setState(HACover::StateOpening); // report state back to the HA
+    } else if (cmd == HACover::CommandClose) {
+        Serial.println("Command: Close");
+        sender->setState(HACover::StateClosing); // report state back to the HA
+    } else if (cmd == HACover::CommandStop) {
+        Serial.println("Command: Stop");
+        sender->setState(HACover::StateStopped); // report state back to the HA
+    }
+
+    // Available states:
+    // HACover::StateClosed
+    // HACover::StateClosing
+    // HACover::StateOpen
+    // HACover::StateOpening
+    // HACover::StateStopped
+
+    // You can also report position using setPosition() method
+}
+
+void setup() {
+    Serial.begin(9600);
+    Ethernet.begin(mac);
+
+    // optional device's details
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    cover.onCommand(onCoverCommand);
+    cover.setName("My cover"); // optional
+
+    // Optionally you can set retain flag for the HA commands
+    // cover.setRetain(true);
+
+    // Optionally you can enable optimistic mode for the HACover.
+    // In this mode you won't need to report state back to the HA when commands are executed.
+    // cover.setOptimistic(true);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your cover using a button connected to the device.
+    // cover.setState(HACover::StateOpening); // use any state you want
+}

examples/esp32-cam/camera_pins.h

@@ -0,0 +1,273 @@
+
+#if defined(CAMERA_MODEL_WROVER_KIT)
+#define PWDN_GPIO_NUM    -1
+#define RESET_GPIO_NUM   -1
+#define XCLK_GPIO_NUM    21
+#define SIOD_GPIO_NUM    26
+#define SIOC_GPIO_NUM    27
+
+#define Y9_GPIO_NUM      35
+#define Y8_GPIO_NUM      34
+#define Y7_GPIO_NUM      39
+#define Y6_GPIO_NUM      36
+#define Y5_GPIO_NUM      19
+#define Y4_GPIO_NUM      18
+#define Y3_GPIO_NUM       5
+#define Y2_GPIO_NUM       4
+#define VSYNC_GPIO_NUM   25
+#define HREF_GPIO_NUM    23
+#define PCLK_GPIO_NUM    22
+
+#elif defined(CAMERA_MODEL_ESP_EYE)
+#define PWDN_GPIO_NUM    -1
+#define RESET_GPIO_NUM   -1
+#define XCLK_GPIO_NUM    4
+#define SIOD_GPIO_NUM    18
+#define SIOC_GPIO_NUM    23
+
+#define Y9_GPIO_NUM      36
+#define Y8_GPIO_NUM      37
+#define Y7_GPIO_NUM      38
+#define Y6_GPIO_NUM      39
+#define Y5_GPIO_NUM      35
+#define Y4_GPIO_NUM      14
+#define Y3_GPIO_NUM      13
+#define Y2_GPIO_NUM      34
+#define VSYNC_GPIO_NUM   5
+#define HREF_GPIO_NUM    27
+#define PCLK_GPIO_NUM    25
+
+#elif defined(CAMERA_MODEL_M5STACK_PSRAM)
+#define PWDN_GPIO_NUM     -1
+#define RESET_GPIO_NUM    15
+#define XCLK_GPIO_NUM     27
+#define SIOD_GPIO_NUM     25
+#define SIOC_GPIO_NUM     23
+
+#define Y9_GPIO_NUM       19
+#define Y8_GPIO_NUM       36
+#define Y7_GPIO_NUM       18
+#define Y6_GPIO_NUM       39
+#define Y5_GPIO_NUM        5
+#define Y4_GPIO_NUM       34
+#define Y3_GPIO_NUM       35
+#define Y2_GPIO_NUM       32
+#define VSYNC_GPIO_NUM    22
+#define HREF_GPIO_NUM     26
+#define PCLK_GPIO_NUM     21
+
+#elif defined(CAMERA_MODEL_M5STACK_V2_PSRAM)
+#define PWDN_GPIO_NUM     -1
+#define RESET_GPIO_NUM    15
+#define XCLK_GPIO_NUM     27
+#define SIOD_GPIO_NUM     22
+#define SIOC_GPIO_NUM     23
+
+#define Y9_GPIO_NUM       19
+#define Y8_GPIO_NUM       36
+#define Y7_GPIO_NUM       18
+#define Y6_GPIO_NUM       39
+#define Y5_GPIO_NUM        5
+#define Y4_GPIO_NUM       34
+#define Y3_GPIO_NUM       35
+#define Y2_GPIO_NUM       32
+#define VSYNC_GPIO_NUM    25
+#define HREF_GPIO_NUM     26
+#define PCLK_GPIO_NUM     21
+
+#elif defined(CAMERA_MODEL_M5STACK_WIDE)
+#define PWDN_GPIO_NUM     -1
+#define RESET_GPIO_NUM    15
+#define XCLK_GPIO_NUM     27
+#define SIOD_GPIO_NUM     22
+#define SIOC_GPIO_NUM     23
+
+#define Y9_GPIO_NUM       19
+#define Y8_GPIO_NUM       36
+#define Y7_GPIO_NUM       18
+#define Y6_GPIO_NUM       39
+#define Y5_GPIO_NUM        5
+#define Y4_GPIO_NUM       34
+#define Y3_GPIO_NUM       35
+#define Y2_GPIO_NUM       32
+#define VSYNC_GPIO_NUM    25
+#define HREF_GPIO_NUM     26
+#define PCLK_GPIO_NUM     21
+
+#elif defined(CAMERA_MODEL_M5STACK_ESP32CAM)
+#define PWDN_GPIO_NUM     -1
+#define RESET_GPIO_NUM    15
+#define XCLK_GPIO_NUM     27
+#define SIOD_GPIO_NUM     25
+#define SIOC_GPIO_NUM     23
+
+#define Y9_GPIO_NUM       19
+#define Y8_GPIO_NUM       36
+#define Y7_GPIO_NUM       18
+#define Y6_GPIO_NUM       39
+#define Y5_GPIO_NUM        5
+#define Y4_GPIO_NUM       34
+#define Y3_GPIO_NUM       35
+#define Y2_GPIO_NUM       17
+#define VSYNC_GPIO_NUM    22
+#define HREF_GPIO_NUM     26
+#define PCLK_GPIO_NUM     21
+
+#elif defined(CAMERA_MODEL_M5STACK_UNITCAM)
+#define PWDN_GPIO_NUM     -1
+#define RESET_GPIO_NUM    15
+#define XCLK_GPIO_NUM     27
+#define SIOD_GPIO_NUM     25
+#define SIOC_GPIO_NUM     23
+
+#define Y9_GPIO_NUM       19
+#define Y8_GPIO_NUM       36
+#define Y7_GPIO_NUM       18
+#define Y6_GPIO_NUM       39
+#define Y5_GPIO_NUM        5
+#define Y4_GPIO_NUM       34
+#define Y3_GPIO_NUM       35
+#define Y2_GPIO_NUM       32
+#define VSYNC_GPIO_NUM    22
+#define HREF_GPIO_NUM     26
+#define PCLK_GPIO_NUM     21
+
+#elif defined(CAMERA_MODEL_AI_THINKER)
+#define PWDN_GPIO_NUM     32
+#define RESET_GPIO_NUM    -1
+#define XCLK_GPIO_NUM      0
+#define SIOD_GPIO_NUM     26
+#define SIOC_GPIO_NUM     27
+
+#define Y9_GPIO_NUM       35
+#define Y8_GPIO_NUM       34
+#define Y7_GPIO_NUM       39
+#define Y6_GPIO_NUM       36
+#define Y5_GPIO_NUM       21
+#define Y4_GPIO_NUM       19
+#define Y3_GPIO_NUM       18
+#define Y2_GPIO_NUM        5
+#define VSYNC_GPIO_NUM    25
+#define HREF_GPIO_NUM     23
+#define PCLK_GPIO_NUM     22
+
+#elif defined(CAMERA_MODEL_TTGO_T_JOURNAL)
+#define PWDN_GPIO_NUM      0
+#define RESET_GPIO_NUM    15
+#define XCLK_GPIO_NUM     27
+#define SIOD_GPIO_NUM     25
+#define SIOC_GPIO_NUM     23
+
+#define Y9_GPIO_NUM       19
+#define Y8_GPIO_NUM       36
+#define Y7_GPIO_NUM       18
+#define Y6_GPIO_NUM       39
+#define Y5_GPIO_NUM        5
+#define Y4_GPIO_NUM       34
+#define Y3_GPIO_NUM       35
+#define Y2_GPIO_NUM       17
+#define VSYNC_GPIO_NUM    22
+#define HREF_GPIO_NUM     26
+#define PCLK_GPIO_NUM     21
+
+
+#elif defined(CAMERA_MODEL_ESP32_CAM_BOARD)
+// The 18 pin header on the board has Y5 and Y3 swapped
+#define USE_BOARD_HEADER 0 
+#define PWDN_GPIO_NUM    32
+#define RESET_GPIO_NUM   33
+#define XCLK_GPIO_NUM     4
+#define SIOD_GPIO_NUM    18
+#define SIOC_GPIO_NUM    23
+
+#define Y9_GPIO_NUM      36
+#define Y8_GPIO_NUM      19
+#define Y7_GPIO_NUM      21
+#define Y6_GPIO_NUM      39
+#if USE_BOARD_HEADER
+#define Y5_GPIO_NUM      13
+#else
+#define Y5_GPIO_NUM      35
+#endif
+#define Y4_GPIO_NUM      14
+#if USE_BOARD_HEADER
+#define Y3_GPIO_NUM      35
+#else
+#define Y3_GPIO_NUM      13
+#endif
+#define Y2_GPIO_NUM      34
+#define VSYNC_GPIO_NUM    5
+#define HREF_GPIO_NUM    27
+#define PCLK_GPIO_NUM    25
+
+#elif defined(CAMERA_MODEL_ESP32S3_CAM_LCD)
+#define PWDN_GPIO_NUM     -1
+#define RESET_GPIO_NUM    -1
+#define XCLK_GPIO_NUM     40
+#define SIOD_GPIO_NUM     17
+#define SIOC_GPIO_NUM     18
+
+#define Y9_GPIO_NUM       39
+#define Y8_GPIO_NUM       41
+#define Y7_GPIO_NUM       42
+#define Y6_GPIO_NUM       12
+#define Y5_GPIO_NUM       3
+#define Y4_GPIO_NUM       14
+#define Y3_GPIO_NUM       47
+#define Y2_GPIO_NUM       13
+#define VSYNC_GPIO_NUM    21
+#define HREF_GPIO_NUM     38
+#define PCLK_GPIO_NUM     11
+
+#elif defined(CAMERA_MODEL_ESP32S2_CAM_BOARD)
+// The 18 pin header on the board has Y5 and Y3 swapped
+#define USE_BOARD_HEADER 0
+#define PWDN_GPIO_NUM     1
+#define RESET_GPIO_NUM    2
+#define XCLK_GPIO_NUM     42
+#define SIOD_GPIO_NUM     41
+#define SIOC_GPIO_NUM     18
+
+#define Y9_GPIO_NUM       16
+#define Y8_GPIO_NUM       39
+#define Y7_GPIO_NUM       40
+#define Y6_GPIO_NUM       15
+#if USE_BOARD_HEADER
+#define Y5_GPIO_NUM       12
+#else
+#define Y5_GPIO_NUM       13
+#endif
+#define Y4_GPIO_NUM       5
+#if USE_BOARD_HEADER
+#define Y3_GPIO_NUM       13
+#else
+#define Y3_GPIO_NUM       12
+#endif
+#define Y2_GPIO_NUM       14
+#define VSYNC_GPIO_NUM    38
+#define HREF_GPIO_NUM     4
+#define PCLK_GPIO_NUM     3
+
+#elif defined(CAMERA_MODEL_ESP32S3_EYE)
+#define PWDN_GPIO_NUM -1
+#define RESET_GPIO_NUM -1
+#define XCLK_GPIO_NUM 15
+#define SIOD_GPIO_NUM 4
+#define SIOC_GPIO_NUM 5
+
+#define Y2_GPIO_NUM 11
+#define Y3_GPIO_NUM 9
+#define Y4_GPIO_NUM 8
+#define Y5_GPIO_NUM 10
+#define Y6_GPIO_NUM 12
+#define Y7_GPIO_NUM 18
+#define Y8_GPIO_NUM 17
+#define Y9_GPIO_NUM 16
+
+#define VSYNC_GPIO_NUM 6
+#define HREF_GPIO_NUM 7
+#define PCLK_GPIO_NUM 13
+
+#else
+#error "Camera model not selected"
+#endif

examples/esp32-cam/esp32-cam.ino

@@ -0,0 +1,185 @@
+#include <WiFi.h>
+#include <ArduinoHA.h>
+#include "esp_camera.h"
+
+#define BROKER_ADDR       IPAddress(192,168,0,17)
+#define WIFI_SSID         "MyNetwork"
+#define WIFI_PASSWORD     "MyPassword"
+#define PUBLISH_INTERVAL  10000 // how often image should be published to HA (milliseconds)
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+HACamera haCamera("myCamera");
+unsigned long lastPublishAt = 0;
+
+// ===================
+// Select camera model
+// ===================
+//#define CAMERA_MODEL_WROVER_KIT // Has PSRAM
+//#define CAMERA_MODEL_ESP_EYE // Has PSRAM
+//#define CAMERA_MODEL_ESP32S3_EYE // Has PSRAM
+//#define CAMERA_MODEL_M5STACK_PSRAM // Has PSRAM
+//#define CAMERA_MODEL_M5STACK_V2_PSRAM // M5Camera version B Has PSRAM
+//#define CAMERA_MODEL_M5STACK_WIDE // Has PSRAM
+//#define CAMERA_MODEL_M5STACK_ESP32CAM // No PSRAM
+//#define CAMERA_MODEL_M5STACK_UNITCAM // No PSRAM
+#define CAMERA_MODEL_AI_THINKER // Has PSRAM
+//#define CAMERA_MODEL_TTGO_T_JOURNAL // No PSRAM
+// ** Espressif Internal Boards **
+//#define CAMERA_MODEL_ESP32_CAM_BOARD
+//#define CAMERA_MODEL_ESP32S2_CAM_BOARD
+//#define CAMERA_MODEL_ESP32S3_CAM_LCD
+
+#include "camera_pins.h"
+
+bool setupCamera();
+void startCameraServer();
+void publishCameraImage();
+
+void setup() {
+  // Unique ID must be set!
+  byte mac[6];
+  WiFi.macAddress(mac);
+  device.setUniqueId(mac, sizeof(mac));
+  
+  Serial.begin(115200);
+  Serial.setDebugOutput(true);
+  Serial.println();
+
+  if (!setupCamera()) {
+    return;
+  }
+
+  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
+  WiFi.setSleep(false);
+
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println("");
+  Serial.println("WiFi connected");
+
+  startCameraServer();
+
+  Serial.print("Camera Ready! Use 'http://");
+  Serial.print(WiFi.localIP());
+  Serial.println("' to connect");
+
+  // set device's details (optional)
+  device.setName("ESP32-CAM");
+  device.setSoftwareVersion("1.0.0");
+
+  haCamera.setIcon("mdi:home");
+  haCamera.setName("Garden camera");
+
+  mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+  mqtt.loop();
+
+  if (millis() - lastPublishAt > PUBLISH_INTERVAL) {
+    Serial.println("Publishing image");
+    publishCameraImage();  
+  }
+}
+
+bool setupCamera() {
+  camera_config_t config;
+  config.ledc_channel = LEDC_CHANNEL_0;
+  config.ledc_timer = LEDC_TIMER_0;
+  config.pin_d0 = Y2_GPIO_NUM;
+  config.pin_d1 = Y3_GPIO_NUM;
+  config.pin_d2 = Y4_GPIO_NUM;
+  config.pin_d3 = Y5_GPIO_NUM;
+  config.pin_d4 = Y6_GPIO_NUM;
+  config.pin_d5 = Y7_GPIO_NUM;
+  config.pin_d6 = Y8_GPIO_NUM;
+  config.pin_d7 = Y9_GPIO_NUM;
+  config.pin_xclk = XCLK_GPIO_NUM;
+  config.pin_pclk = PCLK_GPIO_NUM;
+  config.pin_vsync = VSYNC_GPIO_NUM;
+  config.pin_href = HREF_GPIO_NUM;
+  config.pin_sscb_sda = SIOD_GPIO_NUM;
+  config.pin_sscb_scl = SIOC_GPIO_NUM;
+  config.pin_pwdn = PWDN_GPIO_NUM;
+  config.pin_reset = RESET_GPIO_NUM;
+  config.xclk_freq_hz = 20000000;
+  config.frame_size = FRAMESIZE_UXGA;
+  config.pixel_format = PIXFORMAT_JPEG; // for streaming
+  //config.pixel_format = PIXFORMAT_RGB565; // for face detection/recognition
+  config.grab_mode = CAMERA_GRAB_WHEN_EMPTY;
+  config.fb_location = CAMERA_FB_IN_PSRAM;
+  config.jpeg_quality = 12;
+  config.fb_count = 1;
+  
+  // if PSRAM IC present, init with UXGA resolution and higher JPEG quality
+  //                      for larger pre-allocated frame buffer.
+  if(config.pixel_format == PIXFORMAT_JPEG){
+    if(psramFound()){
+      config.jpeg_quality = 10;
+      config.fb_count = 2;
+      config.grab_mode = CAMERA_GRAB_LATEST;
+    } else {
+      // Limit the frame size when PSRAM is not available
+      config.frame_size = FRAMESIZE_SVGA;
+      config.fb_location = CAMERA_FB_IN_DRAM;
+    }
+  } else {
+    // Best option for face detection/recognition
+    config.frame_size = FRAMESIZE_240X240;
+#if CONFIG_IDF_TARGET_ESP32S3
+    config.fb_count = 2;
+#endif
+  }
+
+#if defined(CAMERA_MODEL_ESP_EYE)
+  pinMode(13, INPUT_PULLUP);
+  pinMode(14, INPUT_PULLUP);
+#endif
+
+  // camera init
+  esp_err_t err = esp_camera_init(&config);
+  if (err != ESP_OK) {
+    Serial.printf("Camera init failed with error 0x%x", err);
+    return false;
+  }
+
+  sensor_t * s = esp_camera_sensor_get();
+  // initial sensors are flipped vertically and colors are a bit saturated
+  if (s->id.PID == OV3660_PID) {
+    s->set_vflip(s, 1); // flip it back
+    s->set_brightness(s, 1); // up the brightness just a bit
+    s->set_saturation(s, -2); // lower the saturation
+  }
+  // drop down frame size for higher initial frame rate
+  if(config.pixel_format == PIXFORMAT_JPEG){
+    s->set_framesize(s, FRAMESIZE_QVGA);
+  }
+
+#if defined(CAMERA_MODEL_M5STACK_WIDE) || defined(CAMERA_MODEL_M5STACK_ESP32CAM)
+  s->set_vflip(s, 1);
+  s->set_hmirror(s, 1);
+#endif
+
+#if defined(CAMERA_MODEL_ESP32S3_EYE)
+  s->set_vflip(s, 1);
+#endif
+
+return true;
+}
+
+void publishCameraImage() {
+  camera_fb_t* fb = esp_camera_fb_get();
+  if (!fb) {
+   return;
+  }
+
+  Serial.printf("Image size: %db\n", fb->len);
+
+  haCamera.publishImage(fb->buf, fb->len);
+  esp_camera_fb_return(fb);
+  lastPublishAt = millis();
+}

examples/esp32-cam/partitions.csv

@@ -0,0 +1,5 @@
+# Name,   Type,  SubType, Offset,   Size,    Flags
+nvs,      data,  nvs,     0x9000,   0x5000,
+otadata,  data,  ota,     0xe000,   0x2000,
+app0,     app,   ota_0,   0x10000,  0x3d0000,
+fr,       data,        ,  0x3e0000, 0x20000,

examples/fan/fan.ino

@@ -0,0 +1,67 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// HAFan::SpeedsFeature enables support for setting different speeds of fan.
+// You can skip this argument if you don't need speed management.
+// "ventilation" is unique ID of the fan. You should define your own ID.
+HAFan fan("ventilation", HAFan::SpeedsFeature);
+
+void onStateCommand(bool state, HAFan* sender) {
+    Serial.print("State: ");
+    Serial.println(state);
+
+    sender->setState(state); // report state back to the Home Assistant
+}
+
+void onSpeedCommand(uint16_t speed, HAFan* sender) {
+    Serial.print("Speed: ");
+    Serial.println(speed);
+
+    sender->setSpeed(speed); // report speed back to the Home Assistant
+}
+
+void setup() {
+    Serial.begin(9600);
+
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // configure fan (optional)
+    fan.setName("Bathroom");
+    fan.setSpeedRangeMin(1);
+    fan.setSpeedRangeMax(100);
+
+    // Optionally you can set retain flag for the HA commands
+    // fan.setRetain(true);
+
+    // Optionally you can enable optimistic mode for the HAFan.
+    // In this mode you won't need to report state back to the HA when commands are executed.
+    // fan.setOptimistic(true);
+
+    // handle fan states
+    fan.onStateCommand(onStateCommand);
+    fan.onSpeedCommand(onSpeedCommand);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your fan using a button connected to the device.
+    // fan.setState(true); // true (ON) or false (OFF)
+}

examples/hvac/hvac.ino

@@ -0,0 +1,109 @@
+#include <ESP8266WiFi.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+#define WIFI_SSID       "MyNetwork"
+#define WIFI_PASSWORD   "MyPassword"
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+
+// By default HAHVAC supports only reporting of the temperature.
+// You can enable feature you need using the second argument of the constructor.
+// Please check the documentation of the HAHVAC class.
+HAHVAC hvac(
+  "my_name",
+  HAHVAC::TargetTemperatureFeature | HAHVAC::PowerFeature | HAHVAC::ModesFeature
+);
+
+unsigned long lastTempPublishAt = 0;
+float lastTemp = 0;
+
+void onTargetTemperatureCommand(HANumeric temperature, HAHVAC* sender) {
+    float temperatureFloat = temperature.toFloat();
+
+    Serial.print("Target temperature: ");
+    Serial.println(temperatureFloat);
+
+    sender->setTargetTemperature(temperature); // report target temperature back to the HA panel
+}
+
+void onPowerCommand(bool state, HAHVAC* sender) {
+  if (state) {
+    Serial.println("Power on");
+  } else {
+    Serial.println("Power off");
+  }
+}
+
+void onModeCommand(HAHVAC::Mode mode, HAHVAC* sender) {
+    Serial.print("Mode: ");
+    if (mode == HAHVAC::OffMode) {
+        Serial.println("off");
+    } else if (mode == HAHVAC::AutoMode) {
+        Serial.println("auto");
+    } else if (mode == HAHVAC::CoolMode) {
+        Serial.println("cool");
+    } else if (mode == HAHVAC::HeatMode) {
+        Serial.println("heat");
+    } else if (mode == HAHVAC::DryMode) {
+        Serial.println("dry");
+    } else if (mode == HAHVAC::FanOnlyMode) {
+        Serial.println("fan only");
+    }
+
+    sender->setMode(mode); // report mode back to the HA panel
+}
+
+void setup() {
+    Serial.begin(9600);
+    Serial.println("Starting...");
+
+    // Unique ID must be set!
+    byte mac[WL_MAC_ADDR_LENGTH];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+
+    // connect to wifi
+    WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
+    while (WiFi.status() != WL_CONNECTED) {
+        Serial.print(".");
+        delay(500); // waiting for the connection
+    }
+    Serial.println();
+    Serial.println("Connected to the network");
+
+    // set device's details (optional)
+    device.setName("NodeMCU");
+    device.setSoftwareVersion("1.0.0");
+
+    // assign callbacks (optional)
+    hvac.onTargetTemperatureCommand(onTargetTemperatureCommand);
+    hvac.onPowerCommand(onPowerCommand);
+    hvac.onModeCommand(onModeCommand);
+
+    // configure HVAC (optional)
+    hvac.setName("My HVAC");
+    hvac.setMinTemp(10);
+    hvac.setMaxTemp(30);
+    hvac.setTempStep(0.5);
+
+    // You can set retain flag for the HA commands
+    // hvac.setRetain(true);
+
+    // You can choose which modes should be available in the HA panel
+    // hvac.setModes(HAHVAC::OffMode | HAHVAC::CoolMode);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    mqtt.loop();
+
+    if ((millis() - lastTempPublishAt) > 3000) {
+        hvac.setCurrentTemperature(lastTemp);
+        lastTempPublishAt = millis();
+        lastTemp += 0.5;
+    }
+}

examples/led-switch/led-switch.ino

@@ -9,11 +9,14 @@ byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
 EthernetClient client;
 HADevice device(mac, sizeof(mac));
 HAMqtt mqtt(client, device);
-HASwitch led("led", false, mqtt); // you can use custom name in place of "led"
 
-void onSwitchStateChanged(bool state, HASwitch* s)
+// "led" is unique ID of the switch. You should define your own ID.
+HASwitch led("led");
+
+void onSwitchCommand(bool state, HASwitch* sender)
 {
     digitalWrite(LED_PIN, (state ? HIGH : LOW));
+    sender->setState(state); // report state back to the Home Assistant
 }
 
 void setup() {
@@ -27,8 +30,17 @@ void setup() {
     device.setName("Arduino");
     device.setSoftwareVersion("1.0.0");
 
+    // set icon (optional)
+    led.setIcon("mdi:lightbulb");
+    led.setName("My LED");
+    // led.setPayloadOn("ENABLE");
+    // led.setPayloadOff("DISABLE");
+    // led.setStateOn("running");
+    // led.setStateOff("stopped");
+    // led.setCommandTemplate("{{ value_json.command }}");
+
     // handle switch state
-    led.onStateChanged(onSwitchStateChanged);
+    led.onCommand(onSwitchCommand);
 
     mqtt.begin(BROKER_ADDR);
 }
@@ -36,4 +48,8 @@ void setup() {
 void loop() {
     Ethernet.maintain();
     mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your switch using a button connected to the device.
+    // led.setState(true); // use any state you want
 }

examples/light/light.ino

@@ -0,0 +1,93 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// HALight::BrightnessFeature enables support for setting brightness of the light.
+// HALight::ColorTemperatureFeature enables support for setting color temperature of the light.
+// Both features are optional and you can remove them if they're not needed.
+// "prettyLight" is unique ID of the light. You should define your own ID.
+HALight light("prettyLight", HALight::BrightnessFeature | HALight::ColorTemperatureFeature | HALight::RGBFeature);
+
+void onStateCommand(bool state, HALight* sender) {
+    Serial.print("State: ");
+    Serial.println(state);
+
+    sender->setState(state); // report state back to the Home Assistant
+}
+
+void onBrightnessCommand(uint8_t brightness, HALight* sender) {
+    Serial.print("Brightness: ");
+    Serial.println(brightness);
+
+    sender->setBrightness(brightness); // report brightness back to the Home Assistant
+}
+
+void onColorTemperatureCommand(uint16_t temperature, HALight* sender) {
+    Serial.print("Color temperature: ");
+    Serial.println(temperature);
+
+    sender->setColorTemperature(temperature); // report color temperature back to the Home Assistant
+}
+
+void onRGBColorCommand(HALight::RGBColor color, HALight* sender) {
+    Serial.print("Red: ");
+    Serial.println(color.red);
+    Serial.print("Green: ");
+    Serial.println(color.green);
+    Serial.print("Blue: ");
+    Serial.println(color.blue);
+
+    sender->setRGBColor(color); // report color back to the Home Assistant
+}
+
+void setup() {
+    Serial.begin(9600);
+
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // configure light (optional)
+    light.setName("Bathroom");
+
+    // Optionally you can set retain flag for the HA commands
+    // light.setRetain(true);
+
+    // Maximum brightness level can be changed as follows:
+    // light.setBrightnessScale(50);
+
+    // Optionally you can enable optimistic mode for the HALight.
+    // In this mode you won't need to report state back to the HA when commands are executed.
+    // light.setOptimistic(true);
+
+    // Color temperature range (optional)
+    // light.setMinMireds(50);
+    // light.setMaxMireds(200);
+
+    // handle light states
+    light.onStateCommand(onStateCommand);
+    light.onBrightnessCommand(onBrightnessCommand); // optional
+    light.onColorTemperatureCommand(onColorTemperatureCommand); // optional
+    light.onRGBColorCommand(onRGBColorCommand); // optional
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your light using a button connected to the device.
+    // light.setState(true); // use any state you want
+}

examples/lock/lock.ino

@@ -0,0 +1,56 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// "myLock" is unique ID of the lock. You should define your own ID.
+HALock lock("myLock");
+
+void onLockCommand(HALock::LockCommand cmd, HALock* sender) {
+    if (cmd == HALock::CommandLock) {
+        Serial.println("Command: Lock");
+        sender->setState(HALock::StateLocked); // report state back to the HA
+    } else if (cmd == HALock::CommandUnlock) {
+        Serial.println("Command: Unlock");
+        sender->setState(HALock::StateUnlocked); // report state back to the HA
+    } else if (cmd == HALock::CommandOpen) {
+        if (sender->getCurrentState() != HALock::StateUnlocked) {
+            return; // optionally you can verify if the lock is unlocked before opening
+        }
+
+        Serial.println("Command: Open");
+    }
+}
+
+void setup() {
+    Serial.begin(9600);
+    Ethernet.begin(mac);
+
+    lock.onCommand(onLockCommand);
+    lock.setName("My door lock"); // optional
+    lock.setIcon("mdi:home"); // optional
+
+    // Optionally you can set retain flag for the HA commands
+    // lock.setRetain(true);
+
+    // Optionally you can enable optimistic mode for the HALock.
+    // In this mode you won't need to report state back to the HA when commands are executed.
+    // lock.setOptimistic(true);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your lock using a button connected to the device.
+    // lock.setState(HALock::StateLocked); // use any state you want
+}

examples/mdns/mdns.ino

@@ -0,0 +1,70 @@
+#include <ESP8266WiFi.h>
+#include <ESP8266mDNS.h>
+#include <ArduinoHA.h>
+
+#define LED_PIN         D0
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+#define WIFI_SSID       "MyNetwork"
+#define WIFI_PASSWORD   "MyPassword"
+
+WiFiClient client;
+HADevice device;
+HAMqtt mqtt(client, device);
+
+// "led" is unique ID of the switch. You should define your own ID.
+HASwitch led("led");
+
+void onSwitchCommand(bool state, HASwitch* sender)
+{
+    digitalWrite(LED_PIN, (state ? HIGH : LOW));
+    sender->setState(state); // report state back to the Home Assistant
+}
+
+void setup() {
+    Serial.begin(9600);
+    Serial.println("Starting...");
+
+    // Unique ID must be set!
+    byte mac[WL_MAC_ADDR_LENGTH];
+    WiFi.macAddress(mac);
+    device.setUniqueId(mac, sizeof(mac));
+
+    pinMode(LED_PIN, OUTPUT);
+    digitalWrite(LED_PIN, LOW);
+
+    // connect to wifi
+    WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
+    while (WiFi.status() != WL_CONNECTED) {
+        Serial.print(".");
+        delay(500); // waiting for the connection
+    }
+    Serial.println();
+    Serial.println("Connected to the network");
+
+    if (MDNS.begin("arduinoha")) {
+        // at this stage your device will be available using the domain name "arduinoha.local"
+        Serial.println("MDNS initialized - arduinoha.local");
+    } else {
+        Serial.println("Failed to initialize MDNS");
+        return;
+    }
+
+    // set device's details (optional)
+    device.setName("NodeMCU MDNS");
+    device.setSoftwareVersion("1.0.0");
+
+    // handle switch state
+    led.onCommand(onSwitchCommand);
+    led.setName("My LED"); // optional
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    mqtt.loop();
+    MDNS.update();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your switch using a button connected to the device.
+    // led.setState(true); // use any state you want
+}

examples/mqtt-advanced/mqtt-advanced.ino

@@ -0,0 +1,67 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR         IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+void onMqttMessage(const char* topic, const uint8_t* payload, uint16_t length) {
+    // This callback is called when message from MQTT broker is received.
+    // Please note that you should always verify if the message's topic is the one you expect.
+    // For example: if (strcmp(topic, "myCustomTopic") == 0) { ... }
+
+    Serial.print("New message on topic: ");
+    Serial.println(topic);
+    Serial.print("Data: ");
+    // MQTT payloads are length-delimited; they are not guaranteed to end in NUL.
+    Serial.write(payload, length);
+    Serial.println();
+
+    mqtt.publish("myPublishTopic", "hello");
+}
+
+void onMqttConnected() {
+    Serial.println("Connected to the broker!");
+
+    // You can subscribe to custom topic if you need
+    mqtt.subscribe("myCustomTopic");
+}
+
+void onMqttDisconnected() {
+    Serial.println("Disconnected from the broker!");
+}
+
+void onMqttStateChanged(HAMqtt::ConnectionState state) {
+    Serial.print("MQTT state changed to: ");
+    Serial.println(static_cast<int8_t>(state));
+}
+
+void setup() {
+    Serial.begin(9600);
+    Ethernet.begin(mac);
+
+    mqtt.onMessage(onMqttMessage);
+    mqtt.onConnected(onMqttConnected);
+    mqtt.onDisconnected(onMqttDisconnected);
+    mqtt.onStateChanged(onMqttStateChanged);
+
+    // If you use custom discovery prefix you can change it as following:
+    // mqtt.setDiscoveryPrefix("customPrefix");
+
+    // If you want to change prefix only for non-discovery prefix:
+    // mqtt.setDataPrefix("data");
+
+    // Obtaining state of the MQTT connection:
+    // mqtt.getState();
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+}

examples/mqtt-with-credentials/mqtt-with-credentials.ino

@@ -11,11 +11,14 @@ byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
 EthernetClient client;
 HADevice device(mac, sizeof(mac));
 HAMqtt mqtt(client, device);
-HASwitch led("led", false, mqtt); // you can use custom name in place of "led"
 
-void onSwitchStateChanged(bool state, HASwitch* s)
+// "led" is unique ID of the switch. You should define your own ID.
+HASwitch led("led");
+
+void onSwitchCommand(bool state, HASwitch* sender)
 {
     digitalWrite(LED_PIN, (state ? HIGH : LOW));
+    sender->setState(state); // report state back to the Home Assistant
 }
 
 void setup() {
@@ -30,7 +33,8 @@ void setup() {
     device.setSoftwareVersion("1.0.0");
 
     // handle switch state
-    led.onStateChanged(onSwitchStateChanged);
+    led.onCommand(onSwitchCommand);
+    led.setName("My LED"); // optional
 
     mqtt.begin(BROKER_ADDR, BROKER_USERNAME, BROKER_PASSWORD);
 }

examples/multi-state-button/multi-state-button.ino

@@ -14,7 +14,9 @@ byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
 EthernetClient client;
 HADevice device(mac, sizeof(mac));
 HAMqtt mqtt(client, device);
-HATriggers triggers(mqtt);
+
+HADeviceTrigger shortPressTrigger(HADeviceTrigger::ButtonShortPressType, BUTTON_NAME);
+HADeviceTrigger longPressTrigger(HADeviceTrigger::ButtonLongPressType, BUTTON_NAME);
 Button btn(BUTTON_PIN);
 bool holdingBtn = false;
 
@@ -22,15 +24,11 @@ void setup() {
     // you don't need to verify return status
     Ethernet.begin(mac);
 
-    Serial.println(Ethernet.localIP());
-
     // set device's details (optional)
     device.setName("Arduino");
     device.setSoftwareVersion("1.0.0");
 
-    // setup triggers
-    triggers.add("button_short_press", BUTTON_NAME);
-    triggers.add("button_long_press", BUTTON_NAME);
+    // setup JC button
     btn.begin();
 
     mqtt.begin(BROKER_ADDR);
@@ -42,13 +40,13 @@ void loop() {
     btn.read();
 
     if (btn.pressedFor(3000) && !holdingBtn) {
-        triggers.trigger("button_long_press", BUTTON_NAME);
+        longPressTrigger.trigger();
         holdingBtn = true;
     } else if (btn.wasReleased()) {
         if (holdingBtn) {
             holdingBtn = false;
         } else {
-            triggers.trigger("button_short_press", BUTTON_NAME);
+            shortPressTrigger.trigger();
         }
     }
 }

examples/multi-switch/multi-switch.ino

@@ -0,0 +1,47 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// devices types go here
+HASwitch switch1("mySwitch1");
+HASwitch switch2("mySwitch2");
+
+void onSwitchCommand(bool state, HASwitch* sender)
+{
+    if (sender == &switch1) {
+        // the switch1 has been toggled
+        // state == true means ON state
+    } else if (sender == &switch2) {
+        // the switch2 has been toggled
+        // state == true means ON state
+    }
+
+    sender->setState(state); // report state back to the Home Assistant
+}
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    switch1.setName("Pretty label 1");
+    switch1.setIcon("mdi:lightbulb");
+    switch1.onCommand(onSwitchCommand);
+
+    switch2.setName("Pretty label 2");
+    switch2.setIcon("mdi:lightbulb");
+    switch2.onCommand(onSwitchCommand);    
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+}

examples/nano33iot/nano33iot.ino

@@ -9,11 +9,14 @@
 WiFiClient client;
 HADevice device;
 HAMqtt mqtt(client, device);
-HASwitch led("led", false, mqtt); // you can use custom name in place of "led"
 
-void onSwitchStateChanged(bool state, HASwitch* s)
+// "led" is unique ID of the switch. You should define your own ID.
+HASwitch led("led");
+
+void onSwitchCommand(bool state, HASwitch* sender)
 {
     digitalWrite(LED_PIN, (state ? HIGH : LOW));
+    sender->setState(state); // report state back to the Home Assistant
 }
 
 void setup() {
@@ -42,11 +45,16 @@ void setup() {
     device.setSoftwareVersion("1.0.0");
 
     // handle switch state
-    led.onStateChanged(onSwitchStateChanged);
+    led.onCommand(onSwitchCommand);
+    led.setName("My LED"); // optional
 
     mqtt.begin(BROKER_ADDR);
 }
 
 void loop() {
     mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your switch using a button connected to the device.
+    // led.setState(true); // use any state you want
 }

examples/nodemcu/nodemcu.ino

@@ -9,11 +9,14 @@
 WiFiClient client;
 HADevice device;
 HAMqtt mqtt(client, device);
-HASwitch led("led", false, mqtt); // you can use custom name in place of "led"
 
-void onSwitchStateChanged(bool state, HASwitch* s)
+// "led" is unique ID of the switch. You should define your own ID.
+HASwitch led("led");
+
+void onSwitchCommand(bool state, HASwitch* sender)
 {
     digitalWrite(LED_PIN, (state ? HIGH : LOW));
+    sender->setState(state); // report state back to the Home Assistant
 }
 
 void setup() {
@@ -42,11 +45,16 @@ void setup() {
     device.setSoftwareVersion("1.0.0");
 
     // handle switch state
-    led.onStateChanged(onSwitchStateChanged);
+    led.onCommand(onSwitchCommand);
+    led.setName("My LED"); // optional
 
     mqtt.begin(BROKER_ADDR);
 }
 
 void loop() {
     mqtt.loop();
+
+    // You can also change the state at runtime as shown below.
+    // This kind of logic can be used if you want to control your switch using a button connected to the device.
+    // led.setState(true); // use any state you want
 }

examples/number/number.ino

@@ -0,0 +1,76 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+HANumber number("myNumber");
+
+// You can also specify the precision of the number by providing the second argument to the constructor as follows:
+// HANumber number("myNumber", HANumber::PrecisionP1);
+// HANumber number("myNumber", HANumber::PrecisionP2);
+// HANumber number("myNumber", HANumber::PrecisionP3);
+
+void onNumberCommand(HANumeric number, HANumber* sender)
+{
+    if (!number.isSet()) {
+        // the reset command was send by Home Assistant
+    } else {
+        // you can do whatever you want with the number as follows:
+        int8_t numberInt8 = number.toInt8();
+        int16_t numberInt16 = number.toInt16();
+        int32_t numberInt32 = number.toInt32();
+        uint8_t numberUInt8 = number.toUInt8();
+        uint16_t numberUInt16 = number.toUInt16();
+        uint32_t numberUInt32 = number.toUInt32();
+        float numberFloat = number.toFloat();
+    }
+
+    sender->setState(number); // report the selected option back to the HA panel
+}
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // handle command from the HA panel
+    number.onCommand(onNumberCommand);
+
+    // Optional configuration
+    number.setIcon("mdi:home");
+    number.setName("My number");
+    // number.setMin(1); // can be float if precision is set via the constructor
+    // number.setMax(100); // can be float if precision is set via the constructor
+    // number.setStep(0.5f); // minimum step: 0.001f
+    // number.setMode(HANumber::ModeBox);
+    // number.setMode(HANumber::ModeSlider);
+    // number.setValueTemplate("{{ value_json.level }}");
+    // number.setPayloadReset("RESET");
+    // number.setCommandTemplate("{{ value | float | round(1) }}");
+
+    // You can set retain flag for the HA commands
+    // number.setRetain(true);
+
+    // You can also enable optimistic mode for the HASelect.
+    // In this mode you won't need to report state back to the HA when commands are executed.
+    // number.setOptimistic(true);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    // You can also report the state to the HA panel at runtime as shown below.
+    // number.setState(1);
+    // number.setState(25.25f); // remember to change precision before using floats
+}

examples/scene/scene.ino

@@ -0,0 +1,43 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+
+// "myScene" is unique IDs of buttons. You should define you own ID.
+HAScene scene("myScene");
+
+void onSceneCommand(HAScene* sender)
+{
+    if (sender == &scene) {
+        // scene was activated via Home Assistant panel
+    }
+}
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // optional device's details
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // optional properties
+    scene.setIcon("mdi:fire");
+    scene.setName("Pretty Scene");
+
+    // press callbacks
+    scene.onCommand(onSceneCommand);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+}

examples/select/select.ino

@@ -0,0 +1,77 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+HASelect mySelect("mySelect");
+
+void onSelectCommand(int8_t index, HASelect* sender)
+{
+    switch (index) {
+    case 0:
+        // Option "Low" was selected
+        break;
+
+    case 1:
+        // Option "Medium" was selected
+        break;
+
+    case 2:
+        // Option "High" was selected
+        break;
+
+    default:
+        // unknown option
+        return;
+    }
+
+    sender->setState(index); // report the selected option back to the HA panel
+
+    // it may return null
+    if (sender->getCurrentOption()) {
+        Serial.print("Current option: ");
+        Serial.println(sender->getCurrentOption());
+    }
+}
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // set available options
+    mySelect.setOptions("Low;Medium;High"); // use semicolons as separator of options
+    mySelect.onCommand(onSelectCommand);
+
+    mySelect.setIcon("mdi:home"); // optional
+    mySelect.setName("My dropdown"); // optional
+
+    // Optionally you can set retain flag for the HA commands
+    // mySelect.setRetain(true);
+
+    // Optionally you can enable optimistic mode for the HASelect.
+    // In this mode you won't need to report state back to the HA when commands are executed.
+    // mySelect.setOptimistic(true);
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    // You can also report the state to the HA panel at runtime as shown below.
+    // The integer corresponds to the option's index.
+    // mySelect.setState(1);
+
+    // You can also reset the select as follows:
+    // mySelect.setState(-1);
+}

examples/sensor-analog/sensor-analog.ino

@@ -0,0 +1,53 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define ANALOG_PIN      A0
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+unsigned long lastUpdateAt = 0;
+
+// "myAnalogInput" is unique ID of the sensor. You should define your own ID.
+HASensorNumber analogSensor("myAnalogInput", HASensorNumber::PrecisionP1);
+
+// You can also specify the precision of the sensor by providing the second argument to the constructor as follows:
+// HASensorNumber analogSensor("myAnalogInput", HASensorNumber::PrecisionP2);
+// HASensorNumber analogSensor("myAnalogInput", HASensorNumber::PrecisionP3);
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // configure sensor (optional)
+    analogSensor.setIcon("mdi:home");
+    analogSensor.setName("Analog voltage");
+    analogSensor.setUnitOfMeasurement("V");
+    analogSensor.setSuggestedDisplayPrecision(2);
+    // analogSensor.setValueTemplate("{{ value_json.voltage }}");
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    if ((millis() - lastUpdateAt) > 1000) { // 1000ms debounce time
+        uint16_t reading = analogRead(ANALOG_PIN);
+        float voltage = reading * 5.f / 1023.f; // 0.0V - 5.0V
+
+        analogSensor.setValue(voltage);
+        lastUpdateAt = millis();
+
+        // you can reset the sensor as follows:
+        // analogSensor.setValue(nullptr);
+    }
+}

examples/sensor-integer/sensor-integer.ino

@@ -0,0 +1,44 @@
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+
+#define BROKER_ADDR IPAddress(192,168,0,17)
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+unsigned long lastUpdateAt = 0;
+
+// "myUptime" is unique ID of the sensor. You should define your own ID.
+HASensorNumber uptimeSensor("myUptime");
+
+void setup() {
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    // configure sensor (optional)
+    uptimeSensor.setIcon("mdi:home");
+    uptimeSensor.setName("Uptime");
+    uptimeSensor.setUnitOfMeasurement("s");
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    if ((millis() - lastUpdateAt) > 2000) { // update in 2s interval
+        unsigned long uptimeValue = millis() / 1000;
+        uptimeSensor.setValue(uptimeValue);
+        lastUpdateAt = millis();
+
+        // you can reset the sensor as follows:
+        // analogSensor.setValue(nullptr);
+    }
+}

examples/sensor/sensor.ino

@@ -4,27 +4,13 @@
 #define BROKER_ADDR IPAddress(192,168,0,17)
 
 byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
-unsigned long lastSentAt = millis();
-double lastValue = 0;
 
 EthernetClient client;
 HADevice device(mac, sizeof(mac));
 HAMqtt mqtt(client, device);
 
-/**
- * Supported data types:
- * - uint8_t
- * - uint16_t
- * - uint32_t
- * - int8_t
- * - int16_t
- * - int32_t
- * - double
- * - float
- */
-// you can use custom name in place of "temp"
-// "0" is initial value of the sensor
-HASensor<double> temp("temp", 0, mqtt);
+// "myValve" is unique ID of the sensor. You should define your own ID.
+HASensor valve("myValve");
 
 void setup() {
     // you don't need to verify return status
@@ -34,8 +20,13 @@ void setup() {
     device.setName("Arduino");
     device.setSoftwareVersion("1.0.0");
 
-    // you can set custom units for the sensor (optional)
-    temp.setUnitOfMeasurement("°C");
+    // configure sensor (optional)
+    valve.setIcon("mdi:home");
+    valve.setName("Water valve");
+    // valve.setValueTemplate("{{ value_json.state }}");
+    // valve.setDeviceClass("enum");
+    // valve.setOptions("open;opening;closed");
+    // valve.setDefaultEntityId("sensor.water_valve");
 
     mqtt.begin(BROKER_ADDR);
 }
@@ -44,9 +35,11 @@ void loop() {
     Ethernet.maintain();
     mqtt.loop();
 
-    if ((millis() - lastSentAt) >= 5000) {
-        lastSentAt = millis();
-        lastValue = lastValue + 0.5;
-        temp.setValue(lastValue);
-    }
+    // you can report different states as follows:
+    // valve.setValue("open");
+    // valve.setValue("opening");
+    // valve.setValue("close");
+
+    // Unlike the other device types, the HASensor doesn't store the previous value that was set.
+    // It means that the MQTT message is produced each time the setValue method is called.
 }

examples/tag-scanner/tag-scanner.ino

@@ -0,0 +1,79 @@
+/**
+ * This example uses MFRC522 library: https://github.com/miguelbalboa/rfid
+ * 
+ * Typical pin layout used:
+ * -----------------------------------------------------------------------------------------
+ *             MFRC522      Arduino       Arduino   Arduino    Arduino          Arduino
+ *             Reader/PCD   Uno/101       Mega      Nano v3    Leonardo/Micro   Pro Micro
+ * Signal      Pin          Pin           Pin       Pin        Pin              Pin
+ * -----------------------------------------------------------------------------------------
+ * RST/Reset   RST          9             5         D9         RESET/ICSP-5     RST
+ * SPI SS      SDA(SS)      10            53        D10        10               10
+ * SPI MOSI    MOSI         11 / ICSP-4   51        D11        ICSP-4           16
+ * SPI MISO    MISO         12 / ICSP-1   50        D12        ICSP-1           14
+ * SPI SCK     SCK          13 / ICSP-3   52        D13        ICSP-3           15
+*/
+
+#include <Ethernet.h>
+#include <ArduinoHA.h>
+#include <SPI.h>
+#include <MFRC522.h>
+
+#define SS_PIN          53 // Arduino Mega
+#define RST_PIN         5 // Arduino Mega
+#define BROKER_ADDR     IPAddress(192,168,0,17)
+#define SCAN_INTERVAL   5000
+
+byte mac[] = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};
+
+MFRC522 rfid(SS_PIN, RST_PIN);
+EthernetClient client;
+HADevice device(mac, sizeof(mac));
+HAMqtt mqtt(client, device);
+HATagScanner scanner("myScanner");
+unsigned long lastTagScannedAt = 0;
+
+void scan() {
+    if (!rfid.PICC_IsNewCardPresent() || !rfid.PICC_ReadCardSerial()) {
+        return;
+    }
+
+    if (millis() - lastTagScannedAt < SCAN_INTERVAL) {
+        return; // prevents spamming the HA. You can implement your own logic for debouncing the scans.
+    }
+
+    // the tag UID needs to be converted into string
+    char tag[rfid.uid.size*2+1] = {0};
+    HAUtils::byteArrayToStr(tag, rfid.uid.uidByte, rfid.uid.size);
+
+    Serial.print("Card scanned: ");
+    Serial.println(tag);
+
+    scanner.tagScanned(tag); // let the HA know about the scanned tag
+    lastTagScannedAt = millis();
+}
+
+void setup() {
+    Serial.begin(9600);
+    Serial.println("Starting...");
+
+    // you don't need to verify return status
+    Ethernet.begin(mac);
+
+    SPI.begin(); // Init SPI bus
+    rfid.PCD_Init();
+    rfid.PCD_DumpVersionToSerial();
+
+    // set device's details (optional)
+    device.setName("Arduino");
+    device.setSoftwareVersion("1.0.0");
+
+    mqtt.begin(BROKER_ADDR);
+}
+
+void loop() {
+    Ethernet.maintain();
+    mqtt.loop();
+
+    scan();
+}

library.json

@@ -0,0 +1,48 @@
+{
+  "name": "home-assistant-integration",
+  "version": "3.2.1",
+  "description": "Maintained Home Assistant MQTT discovery and entity integration for Arduino and ESP devices.",
+  "keywords": [
+    "mqtt",
+    "home-assistant",
+    "homeassistant",
+    "arduino",
+    "esp8266",
+    "esp32",
+    "communication",
+    "smarthome"
+  ],
+  "authors": [
+    {
+      "name": "Dawid Chyrzynski",
+      "email": "dev@chyrzynski.pl"
+    },
+    {
+      "name": "Alex Hope-O'Connor",
+      "email": "alex.hope.oconnor@pomonaqld.au",
+      "maintainer": true
+    }
+  ],
+  "license": "AGPL-3.0",
+  "homepage": "https://github.com/alexhopeoconnor/arduino-home-assistant",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/alexhopeoconnor/arduino-home-assistant.git"
+  },
+  "frameworks": "arduino",
+  "dependencies": {
+    "knolleary/PubSubClient": "2.8.0"
+  },
+  "export": {
+    "include": [
+      "src",
+      "examples",
+      "library.properties",
+      "library.json",
+      "README.md",
+      "LICENSE",
+      "CHANGELOG.md"
+    ]
+  },
+  "$schema": "https://raw.githubusercontent.com/platformio/platformio-core/develop/platformio/assets/schema/library.json"
+}

library.properties

@@ -1,10 +1,10 @@
 name=home-assistant-integration
-version=1.1.1
-author=Dawid Chyrzynski <dawid.chyrzynski@gmail.com>
-maintainer=Dawid Chyrzynski <dawid.chyrzynski@gmail.com>
+version=3.2.1
+author=Dawid Chyrzynski <dev@chyrzynski.pl>, Alex Hope-O'Connor <alex.hope.oconnor@pomonaqld.au>
+maintainer=Alex Hope-O'Connor <alex.hope.oconnor@pomonaqld.au>
 sentence=Home Assistant MQTT integration for Arduino
 paragraph=Lightweight library that provides easy to use API for integrating your Arduino/ESP based device with Home Assistant.
 category=Communication
-url=https://github.com/dawidchyrzynski/arduino-home-assistant
+url=https://github.com/alexhopeoconnor/arduino-home-assistant
 architectures=*
 depends=PubSubClient

platformio.ini

@@ -0,0 +1,74 @@
+; PlatformIO — Unity tests for home-assistant-integration (ArduinoHA)
+;
+; Full suite:
+;   pio test -e esp8266
+;   pio test -e esp32
+;   ./scripts/test.sh compile --platform esp32
+;
+; Single suite (examples):
+;   pio test -e esp8266 --filter test_utils_serializers
+;   pio test -e esp8266 --filter test_mqtt_core
+;   pio test -e esp8266 --filter test_entities_basic
+;   pio test -e esp8266 --filter test_entities_numeric
+;   pio test -e esp8266 --filter test_entities_extended
+;   pio test -e esp8266 --filter test_entities_misc
+;
+; See: https://docs.platformio.org/en/latest/advanced/unit-testing/structure/hierarchy.html
+
+[platformio]
+default_envs = esp8266
+
+[common]
+framework = arduino
+test_framework = unity
+test_build_src = yes
+monitor_speed = 115200
+build_flags = -DARDUINOHA_TEST
+lib_deps = knolleary/PubSubClient@2.8.0
+
+[env:esp8266]
+extends = common
+test_ignore = test_native_core
+platform = espressif8266
+board = d1_mini
+; Keep root Unity coverage on the same Postmortem relocation-fix snapshot as
+; the maintained ESP8266 examples. See docs/ESP8266-LINKER-WORKAROUND.md.
+platform_packages =
+    platformio/framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git#521ae60a89e64bb0d1eb7a0b7addf620ced5cad3
+
+[env:esp32]
+extends = common
+test_ignore = test_native_core
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.311/platform-espressif32.zip
+board = esp32dev
+build_unflags = -std=gnu++11
+build_flags = ${common.build_flags} -std=gnu++14
+
+; Host-only regression checks for serialization, topic validation, and the
+; PubSubClient mock path. The Arduino compatibility files live exclusively
+; under test/native and are never included in firmware environments.
+[env:native]
+platform = native
+test_framework = unity
+test_build_src = yes
+lib_deps = throwtheswitch/Unity@^2.6.1
+build_flags =
+    -DARDUINOHA_TEST
+    -Itest/native/include
+    -fsanitize=address,undefined
+    -fno-omit-frame-pointer
+build_src_filter =
+    -<*>
+    +<ArduinoHALog.cpp>
+    +<HADevice.cpp>
+    +<HAMqtt.cpp>
+    +<device-types/HABaseDeviceType.cpp>
+    +<device-types/HAText.cpp>
+    +<mocks/PubSubClientMock.cpp>
+    +<utils/HAAvailabilityConfig.cpp>
+    +<utils/HADictionary.cpp>
+    +<utils/HAJson.cpp>
+    +<utils/HANumeric.cpp>
+    +<utils/HASerializer.cpp>
+    +<utils/HASerializerArray.cpp>
+    +<utils/HAUtils.cpp>

scripts/bump-version.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+    echo "Usage: $0 vMAJOR.MINOR.PATCH" >&2
+    exit 2
+}
+
+tag="${1:-}"
+[[ "$tag" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]] || usage
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+version="${tag#v}"
+repo_url="https://github.com/alexhopeoconnor/arduino-home-assistant.git"
+reference_files=(README.md docs/getting-started.md)
+defines_file="$root/src/ArduinoHADefines.h"
+
+current_version="$(sed -n 's/.*"version": "\([^"]*\)".*/\1/p' "$root/library.json" | head -n 1)"
+[[ "$current_version" != "$version" ]] || {
+    echo "library.json already declares $version; choose a new version." >&2
+    exit 1
+}
+version_macro_count="$(grep -Ec '^#define ARDUINOHA_LIBRARY_VERSION "[0-9]+\.[0-9]+\.[0-9]+"$' "$defines_file" || true)"
+[[ "$version_macro_count" -eq 1 ]] || {
+    echo "src/ArduinoHADefines.h must contain exactly one ARDUINOHA_LIBRARY_VERSION macro." >&2
+    exit 1
+}
+grep -q "^## $version$" "$root/CHANGELOG.md" && {
+    echo "CHANGELOG.md already has a $version section; choose a new version." >&2
+    exit 1
+}
+
+sed -i -E '0,/"version": "[0-9]+\.[0-9]+\.[0-9]+"/s//"version": "'"$version"'"/' "$root/library.json"
+sed -i -E "s/^version=[0-9]+\.[0-9]+\.[0-9]+$/version=$version/" "$root/library.properties"
+sed -i -E "s/^#define ARDUINOHA_LIBRARY_VERSION \"[0-9]+\.[0-9]+\.[0-9]+\"$/#define ARDUINOHA_LIBRARY_VERSION \"$version\"/" "$defines_file"
+for file in "${reference_files[@]}"; do
+    sed -i -E "s|${repo_url}#v[0-9]+\.[0-9]+\.[0-9]+|${repo_url}#v${version}|g" "$root/$file"
+done
+
+temp_file="$(mktemp)"
+trap 'rm -f "$temp_file"' EXIT
+{
+    IFS= read -r changelog_heading < "$root/CHANGELOG.md"
+    [[ "$changelog_heading" == "# Changelog" ]] || {
+        echo "CHANGELOG.md must begin with # Changelog" >&2
+        exit 1
+    }
+    printf '%s\n\n## %s\n\n- TODO: Describe this release.\n' "$changelog_heading" "$version"
+    tail -n +2 "$root/CHANGELOG.md"
+} > "$temp_file"
+mv "$temp_file" "$root/CHANGELOG.md"
+
+echo "Updated ArduinoHA declarations and canonical install references to $tag."
+echo "Replace the generated changelog TODO with the release summary, then run scripts/check-docs.sh and scripts/prepare-release.sh $tag."

scripts/check-docs.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+required=(
+    README.md CHANGELOG.md
+    docs/README.md docs/getting-started.md docs/device-and-discovery.md docs/mqtt-usage.md docs/entities.md
+    examples/README.md
+)
+
+check_cpp_fence_scope() {
+    local markdown="$1"
+    awk '
+        function brace_delta(line, copy) {
+            copy = line
+            return gsub(/\{/, "{", copy) - gsub(/\}/, "}", copy)
+        }
+        /^```cpp[[:space:]]*$/ { in_cpp = 1; depth = 0; next }
+        in_cpp && /^```[[:space:]]*$/ { in_cpp = 0; next }
+        in_cpp {
+            line = $0
+            sub(/^[[:space:]]+/, "", line)
+            if (depth == 0 &&
+                (line ~ /^(if|for|while|switch)[[:space:]]*\(/ ||
+                 line ~ /^[A-Za-z_][A-Za-z0-9_:]*::[A-Za-z0-9_]+[[:space:]]*\(/ ||
+                 line ~ /^[A-Za-z_][A-Za-z0-9_]*\./ ||
+                 line ~ /^[A-Za-z_][A-Za-z0-9_]*[[:space:]]*\(/)) {
+                printf "%s:%d: C++ expression appears at namespace scope; wrap it in a function.\n", FILENAME, FNR > "/dev/stderr"
+                failed = 1
+            }
+            depth += brace_delta($0)
+        }
+        END { exit failed }
+    ' "$markdown"
+}
+
+for path in "${required[@]}"; do
+    [[ -f "$root/$path" ]] || { echo "Missing required documentation: $path" >&2; exit 1; }
+done
+
+while IFS= read -r -d '' markdown; do
+    while IFS= read -r target; do
+        [[ -z "$target" || "$target" == \#* || "$target" == http://* || "$target" == https://* || "$target" == mailto:* ]] && continue
+        target="${target%%#*}"
+        case "$target" in
+            /*) candidate="$root/${target#/}" ;;
+            *) candidate="$(dirname "$markdown")/$target" ;;
+        esac
+        [[ -e "$candidate" ]] || { echo "Broken relative link in ${markdown#$root/}: $target" >&2; exit 1; }
+    done < <(sed -nE 's/.*\]\(([^ )]+)( "[^"]*")?\).*/\1/p' "$markdown")
+done < <(find "$root" -path "$root/.git" -prune -o -path '*/.pio' -prune -o -name '*.md' -type f -print0)
+
+while IFS= read -r example; do
+    for required in README.md platformio.ini; do
+        [[ -f "$example/$required" ]] || { echo "Incomplete guided example: ${example#$root/} is missing $required" >&2; exit 1; }
+    done
+    find "$example" -maxdepth 2 -type f \( -name '*.ino' -o -name '*.cpp' \) -print -quit | grep -q . || {
+        echo "Incomplete guided example: ${example#$root/} has no sketch source" >&2
+        exit 1
+    }
+done < <(find "$root/examples" -mindepth 1 -maxdepth 1 -type d -name '[0-9][0-9]-*' -print | sort)
+
+while IFS= read -r markdown; do
+    check_cpp_fence_scope "$markdown"
+done < <(find "$root" -path "$root/.git" -prune -o -path '*/.pio' -prune -o -name '*.md' -type f -print)
+
+echo "Documentation links and required files passed"

scripts/prepare-release.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+    echo "Usage: $0 vMAJOR.MINOR.PATCH [--tag]"
+    exit 2
+}
+
+tag="${1:-}"
+[[ "$tag" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]] || usage
+[[ "${2:-}" == "" || "${2:-}" == "--tag" ]] || usage
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+version="${tag#v}"
+manifest_version="$(sed -n 's/.*"version": "\([^"]*\)".*/\1/p' "$root/library.json" | head -n 1)"
+
+if [[ "$manifest_version" != "$version" ]]; then
+    echo "library.json is $manifest_version; expected $version for $tag" >&2
+    exit 1
+fi
+defines_file="$root/src/ArduinoHADefines.h"
+version_macro_count="$(grep -Ec '^#define ARDUINOHA_LIBRARY_VERSION "[0-9]+\.[0-9]+\.[0-9]+"$' "$defines_file" || true)"
+if [[ "$version_macro_count" -ne 1 ]]; then
+    echo "src/ArduinoHADefines.h must contain exactly one ARDUINOHA_LIBRARY_VERSION macro." >&2
+    exit 1
+fi
+
+defines_version="$(sed -n 's/^#define ARDUINOHA_LIBRARY_VERSION "\([^"]*\)"$/\1/p' "$defines_file")"
+if [[ "$defines_version" != "$version" ]]; then
+    echo "src/ArduinoHADefines.h is $defines_version; expected $version for $tag" >&2
+    exit 1
+fi
+
+if [[ -f "$root/library.properties" ]]; then
+    properties_version="$(sed -n 's/^version=//p' "$root/library.properties" | head -n 1)"
+    if [[ "$properties_version" != "$version" ]]; then
+        echo "library.properties is $properties_version; expected $version for $tag" >&2
+        exit 1
+    fi
+fi
+
+if ! grep -q "^## ${version}$" "$root/CHANGELOG.md"; then
+    echo "CHANGELOG.md is missing a ## ${version} section" >&2
+    exit 1
+fi
+
+if awk -v heading="## $version" '
+    $0 == heading { found = 1; next }
+    found && /^## / { exit }
+    found { print }
+' "$root/CHANGELOG.md" | grep -Fq 'TODO: Describe this release.'; then
+    echo "CHANGELOG.md still has the generated TODO for $version" >&2
+    exit 1
+fi
+repo_url="https://github.com/alexhopeoconnor/arduino-home-assistant.git"
+validate_reference() {
+    local file="$1"
+    local reference_count
+    reference_count="$(grep -F "$repo_url#v" "$root/$file" | wc -l)"
+    [[ "$reference_count" -eq 1 ]] || { echo "$file must contain exactly one canonical release reference" >&2; exit 1; }
+    grep -Fq "$repo_url#$tag" "$root/$file" || { echo "$file does not reference $tag" >&2; exit 1; }
+}
+validate_reference README.md
+validate_reference docs/getting-started.md
+
+git -C "$root" diff --check
+
+package_dir="$(mktemp -d)"
+trap 'rm -rf "$package_dir"' EXIT
+pio pkg pack "$root" --output "$package_dir/package.tar.gz" >/dev/null
+echo "Validated release metadata and PlatformIO package for $tag"
+
+if [[ "${2:-}" == "--tag" ]]; then
+    git -C "$root" diff --quiet
+    git -C "$root" diff --cached --quiet
+    git -C "$root" tag -a "$tag" -m "Release $tag"
+    echo "Created $tag. Push the branch and tag; GitHub Actions will publish the release."
+fi

scripts/release-notes.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+    echo "Usage: $0 vMAJOR.MINOR.PATCH" >&2
+    exit 2
+}
+
+tag="${1:-}"
+[[ "$tag" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]] || usage
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+version="${tag#v}"
+changelog="$root/CHANGELOG.md"
+output="$(mktemp)"
+trap 'rm -f "$output"' EXIT
+
+awk -v version="$version" '
+    $0 == "## " version { capture = 1; next }
+    capture && /^## / { exit }
+    capture { print }
+' "$changelog" > "$output"
+
+if [[ ! -s "$output" ]]; then
+    echo "No release notes found for $tag in CHANGELOG.md" >&2
+    exit 1
+fi
+
+printf '%s\n\n' "# ArduinoHA $tag"
+cat "$output"

scripts/test.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+    echo "Usage: $0 compile|examples --platform esp8266|esp32" >&2
+    exit 2
+}
+
+[[ $# -eq 3 && ( "${1:-}" == "compile" || "${1:-}" == "examples" ) && "${2:-}" == "--platform" ]] || usage
+case "${3:-}" in
+    esp8266|esp32) environment="${3}" ;;
+    *) usage ;;
+esac
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+pio_for_platform() {
+    if [[ "$environment" != "esp32" ]]; then
+        pio "$@"
+        return
+    fi
+
+    # Keep Core 3.3.11's package-form esptool and generated pioarduino
+    # environment in the persistent cache shared by the maintained framework
+    # repositories. It is never cleared by this script, and isolates this
+    # tested graph from stale global metadata without duplicate downloads.
+    local core_dir packages_dir cache_dir
+    core_dir="${ARDUINOHA_PLATFORMIO_CORE_DIR:-${XDG_CACHE_HOME:-$HOME/.cache}/arduino-framework-platformio/core-3.3.11}"
+    packages_dir="${ARDUINOHA_PLATFORMIO_PACKAGES_DIR:-$core_dir/packages}"
+    cache_dir="${ARDUINOHA_PLATFORMIO_CACHE_DIR:-$core_dir/cache}"
+    install -d -m 700 "$core_dir" "$packages_dir" "$cache_dir"
+    PLATFORMIO_CORE_DIR="$core_dir" PLATFORMIO_PACKAGES_DIR="$packages_dir" \
+        PLATFORMIO_CACHE_DIR="$cache_dir" pio "$@"
+}
+
+case "$1" in
+    compile)
+        # PlatformIO's test command starts many archive jobs by default. This
+        # multi-suite project has a reproducible missing-object race on Core
+        # 3.3.11 at high parallelism, so use a deterministic default while
+        # preserving an explicit caller override.
+        export PLATFORMIO_RUN_JOBS="${PLATFORMIO_RUN_JOBS:-1}"
+        pio_for_platform test -d "$root" -e "$environment" --without-uploading --without-testing
+        echo "ArduinoHA compile check passed for $environment"
+        ;;
+    examples)
+        mapfile -t examples < <(find "$root/examples" -mindepth 1 -maxdepth 1 -type d -name '[0-9][0-9]-*' -print | sort)
+        if (( ${#examples[@]} == 0 )); then
+            echo "No example projects found" >&2
+            exit 1
+        fi
+        for example in "${examples[@]}"; do
+            pio_for_platform run -d "$example" -e "$environment" </dev/null
+        done
+        echo "ArduinoHA examples compile check passed for $environment"
+        ;;
+esac

src/ArduinoHA.h

@@ -1,14 +1,35 @@
 #ifndef AHA_ARDUINOHA_H
 #define AHA_ARDUINOHA_H
 
+#include "ArduinoHALog.h"
+#include "ArduinoHALogTemplates.h"
 #include "HADevice.h"
 #include "HAMqtt.h"
-#include "HAUtils.h"
 #include "device-types/HABinarySensor.h"
+#include "device-types/HAButton.h"
+#include "device-types/HACamera.h"
+#include "device-types/HACover.h"
+#include "device-types/HADeviceTracker.h"
+#include "device-types/HADeviceTrigger.h"
+#include "device-types/HAFan.h"
+#include "device-types/HAHVAC.h"
+#include "device-types/HALight.h"
+#include "device-types/HALock.h"
+#include "device-types/HANumber.h"
+#include "device-types/HAScene.h"
+#include "device-types/HASelect.h"
 #include "device-types/HASensor.h"
-#include "device-types/HASensor.cpp"
+#include "device-types/HASensorNumber.h"
 #include "device-types/HASwitch.h"
 #include "device-types/HATagScanner.h"
-#include "device-types/HATriggers.h"
+#include "device-types/HAText.h"
+#include "utils/HAUtils.h"
+#include "utils/HANumeric.h"
+
+#ifdef ARDUINOHA_TEST
+#include "mocks/PubSubClientMock.h"
+#include "utils/HADictionary.h"
+#include "utils/HASerializer.h"
+#endif
 
 #endif

src/ArduinoHADefines.h

@@ -1,4 +1,63 @@
 // Turns on debug information of the ArduinoHA core.
-// Please note that you need to initialize serial interface manually
-// by calling Serial.begin([baudRate]) before initializing ArduinoHA.
+// Without a log sink (arduinoHASetLogSink), initialize Serial (e.g. Serial.begin(115200)) before ArduinoHA.
+// With a sink installed, the host is responsible for transport setup.
 // #define ARDUINOHA_DEBUG
+
+#include "ArduinoHALog.h"
+
+// These macros allow to exclude some parts of the library to save more resources.
+// #define EX_ARDUINOHA_BINARY_SENSOR
+// #define EX_ARDUINOHA_BUTTON
+// #define EX_ARDUINOHA_CAMERA
+// #define EX_ARDUINOHA_COVER
+// #define EX_ARDUINOHA_DEVICE_TRACKER
+// #define EX_ARDUINOHA_DEVICE_TRIGGER
+// #define EX_ARDUINOHA_FAN
+// #define EX_ARDUINOHA_HVAC
+// #define EX_ARDUINOHA_LIGHT
+// #define EX_ARDUINOHA_LOCK
+// #define EX_ARDUINOHA_NUMBER
+// #define EX_ARDUINOHA_SCENE
+// #define EX_ARDUINOHA_SELECT
+// #define EX_ARDUINOHA_SENSOR
+// #define EX_ARDUINOHA_SWITCH
+// #define EX_ARDUINOHA_TAG_SCANNER
+// #define EX_ARDUINOHA_TEXT
+
+// Enables std::function overloads for entity callbacks.
+// Useful for capturing lambdas, but may increase binary size on constrained boards.
+// Define ARDUINOHA_DISABLE_STDFUNCTION to opt out.
+#if !defined(ARDUINOHA_DISABLE_STDFUNCTION)
+    #define ARDUINOHA_ENABLE_STDFUNCTION
+#endif
+
+// Current library version used in discovery origin metadata.
+#define ARDUINOHA_LIBRARY_VERSION "3.2.1"
+
+#if defined(ARDUINOHA_DEBUG)
+    #include <Arduino.h>
+
+    #define ARDUINOHA_DEBUG_INIT() do { \
+        if (!arduinoHAGetLogSink()) { Serial.begin(115200); } \
+        arduinoHASetLogEnabled(true); \
+        arduinoHASetLogLevel(ArduinoHALogLevel::Debug); \
+    } while(0)
+    /** @deprecated Prefer arduinoHALog / arduinoHALogf; each macro emits one structured line. */
+    #define ARDUINOHA_DEBUG_PRINTLN(x) \
+        arduinoHALog(ArduinoHALogLevel::Debug, "aha", String(x))
+    /** @deprecated Prefer arduinoHALog / arduinoHALogf; each macro emits one structured line. */
+    #define ARDUINOHA_DEBUG_PRINT(x) \
+        arduinoHALog(ArduinoHALogLevel::Debug, "aha", String(x))
+#else
+    #define ARDUINOHA_DEBUG_INIT()
+    #define ARDUINOHA_DEBUG_PRINTLN(x)
+    #define ARDUINOHA_DEBUG_PRINT(x)
+#endif
+
+
+#if defined(__SAMD21G18A__) or defined(__SAM3X8E__) or (defined(ESP32) and defined(ESP_ARDUINO_VERSION_MAJOR) and ESP_ARDUINO_VERSION_MAJOR >= 3)
+    #define ARDUINOHA_INT_OVERLOAD
+#endif
+
+#define AHATOFSTR(x) reinterpret_cast<const __FlashStringHelper*>(x)
+#define AHAFROMFSTR(x) reinterpret_cast<const char*>(x)

src/ArduinoHALog.cpp

@@ -0,0 +1,97 @@
+#include "ArduinoHALog.h"
+
+static ArduinoHALogSink* g_arduinoHALogSink = nullptr;
+static ArduinoHANetworkStatusFn g_networkStatusFn = nullptr;
+
+#ifdef ARDUINOHA_DEBUG
+static bool g_logEnabled = true;
+static ArduinoHALogLevel g_logLevelMax = ArduinoHALogLevel::Debug;
+#else
+static bool g_logEnabled = false;
+static ArduinoHALogLevel g_logLevelMax = ArduinoHALogLevel::Info;
+#endif
+
+void arduinoHASetLogSink(ArduinoHALogSink* sink) {
+    g_arduinoHALogSink = sink;
+}
+
+ArduinoHALogSink* arduinoHAGetLogSink() {
+    return g_arduinoHALogSink;
+}
+
+void arduinoHASetLogEnabled(bool enabled) {
+    g_logEnabled = enabled;
+}
+
+bool arduinoHAIsLogEnabled() {
+    return g_logEnabled;
+}
+
+void arduinoHASetLogLevel(ArduinoHALogLevel level) {
+    g_logLevelMax = level;
+}
+
+ArduinoHALogLevel arduinoHAGetLogLevel() {
+    return g_logLevelMax;
+}
+
+void arduinoHASetNetworkStatusFn(ArduinoHANetworkStatusFn fn) {
+    g_networkStatusFn = fn;
+}
+
+int arduinoHANetworkStatusOptional(void) {
+    if (!g_networkStatusFn) {
+        return -1;
+    }
+    return g_networkStatusFn();
+}
+
+const char* arduinoHALogLevelTag(ArduinoHALogLevel level) {
+    switch (level) {
+        case ArduinoHALogLevel::Error:
+            return "ERROR";
+        case ArduinoHALogLevel::Warn:
+            return "WARN";
+        case ArduinoHALogLevel::Info:
+            return "INFO";
+        case ArduinoHALogLevel::Debug:
+            return "DEBUG";
+        case ArduinoHALogLevel::Trace:
+            return "TRACE";
+        default:
+            return "?";
+    }
+}
+
+void arduinoHALog(
+    ArduinoHALogLevel level,
+    const char* subsystem,
+    const String& text
+) {
+    if (!g_logEnabled) {
+        return;
+    }
+
+    if (static_cast<uint8_t>(level) > static_cast<uint8_t>(g_logLevelMax)) {
+        return;
+    }
+
+    const char* sub = (subsystem && subsystem[0] != '\0') ? subsystem : "aha";
+
+    ArduinoHALogMessage msg;
+    msg.level = level;
+    msg.subsystem = sub;
+    msg.text = text;
+
+    if (g_arduinoHALogSink) {
+        g_arduinoHALogSink->log(msg);
+        return;
+    }
+
+    Serial.print(F("["));
+    Serial.print(arduinoHALogLevelTag(level));
+    Serial.print(F("][aha."));
+    Serial.print(sub);
+    Serial.print(F("] "));
+    Serial.println(text);
+}

src/ArduinoHALog.h

@@ -0,0 +1,65 @@
+#ifndef ARDUINOHA_LOG_H
+#define ARDUINOHA_LOG_H
+
+#include <Arduino.h>
+
+/**
+ * Log severity for ArduinoHA. Numeric order is used for filtering: only messages with
+ * level <= the configured maximum (see arduinoHASetLogLevel) are emitted.
+ */
+enum class ArduinoHALogLevel : uint8_t {
+    Error = 1,
+    Warn,
+    Info,
+    Debug,
+    Trace,
+};
+
+struct ArduinoHALogMessage {
+    ArduinoHALogLevel level;
+    const char* subsystem;
+    String text;
+};
+
+/**
+ * Structured log sink (mirrors WiFiManager-style log callbacks).
+ * Install with arduinoHASetLogSink; when null, arduinoHALog writes to Serial if enabled.
+ */
+class ArduinoHALogSink {
+public:
+    virtual void log(const ArduinoHALogMessage& msg) = 0;
+    virtual ~ArduinoHALogSink() = default;
+};
+
+void arduinoHASetLogSink(ArduinoHALogSink* sink);
+ArduinoHALogSink* arduinoHAGetLogSink();
+
+void arduinoHASetLogEnabled(bool enabled);
+bool arduinoHAIsLogEnabled();
+
+/**
+ * Maximum verbosity to print: Error..Trace. Messages with level <= this value are shown.
+ */
+void arduinoHASetLogLevel(ArduinoHALogLevel level);
+ArduinoHALogLevel arduinoHAGetLogLevel();
+
+void arduinoHALog(
+    ArduinoHALogLevel level,
+    const char* subsystem,
+    const String& text
+);
+
+const char* arduinoHALogLevelTag(ArduinoHALogLevel level);
+
+/**
+ * Optional hook for transport diagnostics (e.g. return WiFi.status()).
+ * When unset, publish failure logs omit network fields.
+ */
+typedef int (*ArduinoHANetworkStatusFn)(void);
+
+void arduinoHASetNetworkStatusFn(ArduinoHANetworkStatusFn fn);
+
+/** Returns -1 when no hook is installed. */
+int arduinoHANetworkStatusOptional(void);
+
+#endif

src/ArduinoHALogTemplates.h

@@ -0,0 +1,58 @@
+#ifndef ARDUINOHA_LOG_TEMPLATES_H
+#define ARDUINOHA_LOG_TEMPLATES_H
+
+#include "ArduinoHALog.h"
+#include <IPAddress.h>
+
+inline String ahaLogStringifyArg(const __FlashStringHelper* v) {
+    return String(v);
+}
+
+inline String ahaLogStringifyArg(const IPAddress& v) {
+    return v.toString();
+}
+
+template<typename T>
+inline String ahaLogStringifyArg(const T& v) {
+    return String(v);
+}
+
+template<typename T>
+inline void arduinoHALogf(
+    ArduinoHALogLevel level,
+    const char* subsystem,
+    T&& text
+) {
+    arduinoHALog(level, subsystem, ahaLogStringifyArg(text));
+}
+
+template<typename T, typename U>
+inline void arduinoHALogf(
+    ArduinoHALogLevel level,
+    const char* subsystem,
+    T&& a,
+    U&& b
+) {
+    arduinoHALog(
+        level,
+        subsystem,
+        ahaLogStringifyArg(a) + ahaLogStringifyArg(b)
+    );
+}
+
+template<typename T, typename U, typename V>
+inline void arduinoHALogf(
+    ArduinoHALogLevel level,
+    const char* subsystem,
+    T&& a,
+    U&& b,
+    V&& c
+) {
+    arduinoHALog(
+        level,
+        subsystem,
+        ahaLogStringifyArg(a) + ahaLogStringifyArg(b) + ahaLogStringifyArg(c)
+    );
+}
+
+#endif

src/HADevice.cpp

@@ -1,13 +1,150 @@
-#include <Arduino.h>
-
+#include "ArduinoHADefines.h"
 #include "HADevice.h"
-#include "HAUtils.h"
+#include "HAMqtt.h"
+#include "utils/HAUtils.h"
+#include "utils/HADictionary.h"
+#include "utils/HAJson.h"
+#include "utils/HASerializer.h"
+#include <string.h>
+
+static bool appendEscapedJsonString(char*& cursor, char* end, const char* value)
+{
+    return HAJson::appendEscapedString(cursor, end, value);
+}
+
+namespace {
+void skipJsonWhitespace(const char*& cursor)
+{
+    while (*cursor == ' ' || *cursor == '\t' || *cursor == '\n' || *cursor == '\r') {
+        cursor++;
+    }
+}
+
+bool isHexDigit(const char value)
+{
+    return (value >= '0' && value <= '9') ||
+        (value >= 'a' && value <= 'f') ||
+        (value >= 'A' && value <= 'F');
+}
+
+bool parseJsonString(const char*& cursor)
+{
+    if (*cursor != '"') {
+        return false;
+    }
+
+    cursor++;
+    while (*cursor != '\0') {
+        const unsigned char value = static_cast<unsigned char>(*cursor++);
+        if (value == '"') {
+            return true;
+        }
+
+        if (value < 0x20) {
+            return false;
+        }
+
+        if (value != '\\') {
+            continue;
+        }
+
+        const char escape = *cursor++;
+        if (escape == '\0') {
+            return false;
+        }
+
+        if (escape == '"' || escape == '\\' || escape == '/' ||
+            escape == 'b' || escape == 'f' || escape == 'n' ||
+            escape == 'r' || escape == 't') {
+            continue;
+        }
+
+        if (escape != 'u') {
+            return false;
+        }
+
+        for (uint8_t i = 0; i < 4; i++) {
+            if (!isHexDigit(*cursor++)) {
+                return false;
+            }
+        }
+    }
+
+    return false;
+}
+
+bool isValidConnectionsJson(const char* value, const size_t maxLength)
+{
+    if (!value || value[0] == '\0' || strlen(value) >= maxLength) {
+        return false;
+    }
+
+    const char* cursor = value;
+    skipJsonWhitespace(cursor);
+    if (*cursor++ != '[') {
+        return false;
+    }
+
+    skipJsonWhitespace(cursor);
+    if (*cursor == ']') {
+        cursor++;
+        skipJsonWhitespace(cursor);
+        return *cursor == '\0';
+    }
+
+    while (true) {
+        if (*cursor++ != '[') {
+            return false;
+        }
+
+        skipJsonWhitespace(cursor);
+        if (!parseJsonString(cursor)) {
+            return false;
+        }
+
+        skipJsonWhitespace(cursor);
+        if (*cursor++ != ',') {
+            return false;
+        }
+
+        skipJsonWhitespace(cursor);
+        if (!parseJsonString(cursor)) {
+            return false;
+        }
+
+        skipJsonWhitespace(cursor);
+        if (*cursor++ != ']') {
+            return false;
+        }
+
+        skipJsonWhitespace(cursor);
+        if (*cursor == ']') {
+            cursor++;
+            skipJsonWhitespace(cursor);
+            return *cursor == '\0';
+        }
+
+        if (*cursor++ != ',') {
+            return false;
+        }
+
+        skipJsonWhitespace(cursor);
+    }
+}
+} // namespace
 
 #define HADEVICE_INIT \
-    _manufacturer(nullptr), \
-    _model(nullptr), \
-    _name(nullptr), \
-    _softwareVersion(nullptr)
+    _ownsUniqueId(false), \
+    _serializer(new HASerializer(nullptr, 16)), \
+    _availabilityTopic(nullptr), \
+    _sharedAvailability(false), \
+    _available(true), \
+    _extendedUniqueIds(false), \
+    _payloadAvailable(nullptr), \
+    _payloadNotAvailable(nullptr), \
+    _connectionsJson(), \
+    _hasConnections(false), \
+    _connectionsPropertyRegistered(false)
 
 HADevice::HADevice() :
     _uniqueId(nullptr),
@@ -20,99 +157,307 @@ HADevice::HADevice(const char* uniqueId) :
     _uniqueId(uniqueId),
     HADEVICE_INIT
 {
-
+    _serializer->set(AHATOFSTR(HADeviceIdentifiersProperty), _uniqueId);
 }
 
-HADevice::HADevice(const byte* uniqueId, const uint16_t& length) :
+HADevice::HADevice(const byte* uniqueId, const uint16_t length) :
     _uniqueId(HAUtils::byteArrayToStr(uniqueId, length)),
     HADEVICE_INIT
 {
-
+    _ownsUniqueId = true;
+    _serializer->set(AHATOFSTR(HADeviceIdentifiersProperty), _uniqueId);
 }
 
-bool HADevice::setUniqueId(const byte* uniqueId, const uint16_t& length)
+HADevice::~HADevice()
 {
-    if (_uniqueId != nullptr) {
-        return false;
+    delete _serializer;
+
+    if (_availabilityTopic) {
+        delete[] _availabilityTopic;
+    }
+
+    if (_ownsUniqueId) {
+        delete[] _uniqueId;
+    }
+}
+
+bool HADevice::setUniqueId(const byte* uniqueId, const uint16_t length)
+{
+    if (_uniqueId) {
+        return false; // unique ID cannot be changed at runtime once it's set
     }
 
     _uniqueId = HAUtils::byteArrayToStr(uniqueId, length);
+    _ownsUniqueId = true;
+    _serializer->set(AHATOFSTR(HADeviceIdentifiersProperty), _uniqueId);
     return true;
 }
 
-uint16_t HADevice::calculateSerializedLength() const
+void HADevice::setManufacturer(const char* manufacturer)
 {
-    uint16_t size =
-        3 + // opening and closing bracket + null terminator
-        strlen(_uniqueId) + 8; // 8 - length of the JSON data for this field
-
-    if (_manufacturer != nullptr) {
-        size += strlen(_manufacturer) + 8; // 8 - length of the JSON data for this field
-    }
-
-    if (_model != nullptr) {
-        size += strlen(_model) + 9; // 9 - length of the JSON data for this field
-    }
-
-    if (_name != nullptr) {
-        size += strlen(_name) + 10; // 10 - length of the JSON data for this field
-    }
-
-    if (_softwareVersion != nullptr) {
-        size += strlen(_softwareVersion) + 8; // 8 - length of the JSON data for this field
-    }
-
-    return size;
+    _serializer->set(AHATOFSTR(HADeviceManufacturerProperty), manufacturer);
 }
 
-uint16_t HADevice::serialize(char* dst) const
+void HADevice::setModel(const char* model)
 {
-    static const char QuotationSign[] PROGMEM = {"\""};
+    _serializer->set(AHATOFSTR(HADeviceModelProperty), model);
+}
 
-    {
-        static const char DataBefore[] PROGMEM = {"{\"ids\":\""};
+void HADevice::setName(const char* name)
+{
+    _serializer->set(AHATOFSTR(HANameProperty), name);
+}
 
-        strcpy_P(dst, DataBefore);
-        strcat(dst, _uniqueId);
-        strcat_P(dst, QuotationSign);
+void HADevice::setSoftwareVersion(const char* softwareVersion)
+{
+    _serializer->set(
+        AHATOFSTR(HADeviceSoftwareVersionProperty),
+        softwareVersion
+    );
+}
+
+void HADevice::setConfigurationUrl(const char* url)
+{
+    _serializer->set(
+        AHATOFSTR(HADeviceConfigurationUrlProperty),
+        url
+    );
+}
+
+void HADevice::setModelId(const char* modelId)
+{
+    if (!modelId) {
+        return;
+    }
+
+    _serializer->set(AHATOFSTR(HADeviceModelIdProperty), modelId);
+}
+
+void HADevice::setHardwareVersion(const char* hardwareVersion)
+{
+    if (!hardwareVersion) {
+        return;
+    }
+
+    _serializer->set(AHATOFSTR(HADeviceHwVersionProperty), hardwareVersion);
+}
+
+void HADevice::setSerialNumber(const char* serialNumber)
+{
+    if (!serialNumber) {
+        return;
+    }
+
+    _serializer->set(AHATOFSTR(HADeviceSerialNumberProperty), serialNumber);
+}
+
+void HADevice::setSuggestedArea(const char* suggestedArea)
+{
+    if (!suggestedArea) {
+        return;
+    }
+
+    _serializer->set(AHATOFSTR(HADeviceSuggestedAreaProperty), suggestedArea);
+}
+
+void HADevice::setViaDevice(const char* viaDevice)
+{
+    if (!viaDevice) {
+        return;
+    }
+
+    _serializer->set(AHATOFSTR(HADeviceViaDeviceProperty), viaDevice);
+}
+
+bool HADevice::addConnection(const char* type, const char* value)
+{
+    if (!type || !value || type[0] == '\0' || value[0] == '\0') {
+        return false;
+    }
+
+    char next[MaxConnectionsJsonLength];
+    if (_hasConnections) {
+        strncpy(next, _connectionsJson, MaxConnectionsJsonLength - 1);
+        next[MaxConnectionsJsonLength - 1] = 0;
+    } else {
+        strcpy(next, "[]");
+    }
+
+    const size_t len = strlen(next);
+    if (len < 2 || next[len - 1] != ']') {
+        return false;
+    }
+
+    char* cursor = next + len - 1;
+    char* end = next + MaxConnectionsJsonLength - 1;
+
+    if (cursor > next + 1) {
+        if (cursor + 1 >= end) {
+            return false;
+        }
+        *cursor++ = ',';
     }
 
-    if (_manufacturer != nullptr) {
-        static const char DataBefore[] PROGMEM = {",\"mf\":\""};
+    if (cursor + 1 >= end) {
+        return false;
+    }
+    *cursor++ = '[';
+    *cursor = 0;
+
+    if (!appendEscapedJsonString(cursor, end, type)) {
+        return false;
+    }
+
+    if (cursor + 1 >= end) {
+        return false;
+    }
+    *cursor++ = ',';
+    *cursor = 0;
+
+    if (!appendEscapedJsonString(cursor, end, value)) {
+        return false;
+    }
+
+    if (cursor + 2 >= end) {
+        return false;
+    }
+    *cursor++ = ']';
+    *cursor++ = ']';
+    *cursor = 0;
+
+    strncpy(_connectionsJson, next, MaxConnectionsJsonLength - 1);
+    _connectionsJson[MaxConnectionsJsonLength - 1] = 0;
+    _hasConnections = true;
+
+    if (!_connectionsPropertyRegistered) {
+        _serializer->set(
+            AHATOFSTR(HADeviceConnectionsProperty),
+            _connectionsJson,
+            HASerializer::JsonLiteralPropertyValue
+        );
+        _connectionsPropertyRegistered = true;
+    }
 
-        strcat_P(dst, DataBefore);
-        strcat(dst, _manufacturer);
-        strcat_P(dst, QuotationSign);
+    return true;
+}
+
+bool HADevice::setConnectionsJson(const char* connectionsJson)
+{
+    if (!isValidConnectionsJson(connectionsJson, MaxConnectionsJsonLength)) {
+        return false;
+    }
+
+    strcpy(_connectionsJson, connectionsJson);
+    _hasConnections = true;
+
+    if (!_connectionsPropertyRegistered) {
+        _serializer->set(
+            AHATOFSTR(HADeviceConnectionsProperty),
+            _connectionsJson,
+            HASerializer::JsonLiteralPropertyValue
+        );
+        _connectionsPropertyRegistered = true;
     }
+
+    return true;
+}
+
+void HADevice::setPayloadAvailable(const char* payload)
+{
+    _payloadAvailable = payload;
+}
 
-    if (_model != nullptr) {
-        static const char DataBefore[] PROGMEM = {",\"mdl\":\""};
+void HADevice::setPayloadNotAvailable(const char* payload)
+{
+    _payloadNotAvailable = payload;
+}
 
-        strcat_P(dst, DataBefore);
-        strcat(dst, _model);
-        strcat_P(dst, QuotationSign);
+void HADevice::setAvailability(bool online)
+{
+    _available = online;
+    publishAvailability();
+}
+
+bool HADevice::enableSharedAvailability()
+{
+    if (_sharedAvailability) {
+        return true; // already enabled
+    }
+
+    const uint16_t topicLength = HASerializer::calculateDataTopicLength(
+        nullptr,
+        AHATOFSTR(HAAvailabilityTopic)
+    );
+    if (topicLength == 0) {
+        return false;
     }
 
-    if (_name != nullptr) {
-        static const char DataBefore[] PROGMEM = {",\"name\":\""};
+    _availabilityTopic = new char[topicLength];
 
-        strcat_P(dst, DataBefore);
-        strcat(dst, _name);
-        strcat_P(dst, QuotationSign);
+    if (HASerializer::generateDataTopic(
+        _availabilityTopic,
+        nullptr,
+        AHATOFSTR(HAAvailabilityTopic)
+    ) > 0) {
+        _sharedAvailability = true;
+        return true;
     }
 
-    if (_softwareVersion != nullptr) {
-        static const char DataBefore[] PROGMEM = {",\"sw\":\""};
+    return false;
+}
 
-        strcat_P(dst, DataBefore);
-        strcat(dst, _softwareVersion);
-        strcat_P(dst, QuotationSign);
+void HADevice::enableLastWill()
+{
+    HAMqtt* mqtt = HAMqtt::instance();
+    if (!mqtt || !_availabilityTopic) {
+        return;
     }
 
-    {
-        static const char Data[] PROGMEM = {"}"};
-        strcat_P(dst, Data);
+    const char* lw = (_payloadNotAvailable && _payloadNotAvailable[0] != '\0')
+        ? _payloadNotAvailable
+        : "offline";
+
+    mqtt->setLastWill(
+        _availabilityTopic,
+        lw,
+        true
+    );
+}
+
+void HADevice::publishAvailability() const
+{
+    HAMqtt* mqtt = HAMqtt::instance();
+    if (!_availabilityTopic || !mqtt) {
+        return;
     }
 
-    return strlen(dst) + 1; // size with null terminator
+    if (_available) {
+        if (_payloadAvailable && _payloadAvailable[0] != '\0') {
+            const uint16_t len = strlen(_payloadAvailable);
+            if (mqtt->beginPublish(_availabilityTopic, len, true)) {
+                mqtt->writePayload(_payloadAvailable, len);
+                mqtt->endPublish();
+            }
+        } else {
+            const uint16_t len = strlen_P(HAOnline);
+            if (mqtt->beginPublish(_availabilityTopic, len, true)) {
+                mqtt->writePayload(AHATOFSTR(HAOnline));
+                mqtt->endPublish();
+            }
+        }
+    } else {
+        if (_payloadNotAvailable && _payloadNotAvailable[0] != '\0') {
+            const uint16_t len = strlen(_payloadNotAvailable);
+            if (mqtt->beginPublish(_availabilityTopic, len, true)) {
+                mqtt->writePayload(_payloadNotAvailable, len);
+                mqtt->endPublish();
+            }
+        } else {
+            const uint16_t len = strlen_P(HAOffline);
+            if (mqtt->beginPublish(_availabilityTopic, len, true)) {
+                mqtt->writePayload(AHATOFSTR(HAOffline));
+                mqtt->endPublish();
+            }
+        }
+    }
 }

src/HADevice.h

@@ -3,38 +3,228 @@
 
 #include <Arduino.h>
 
+class HASerializer;
+
+/**
+ * This class represents your device that's going to be registered in the Home Assistant devices registry.
+ * Each entity (HABinarySensor, HASensor, etc.) that you use will be owned by this device.
+ */
 class HADevice
 {
 public:
+    /**
+     * Constructs HADevice without the unique ID.
+     *
+     * @note You will need to set the ID using HADevice::setUniqueId method. Otherwise none of the entities will work.
+     */
     HADevice();
-    HADevice(const char* uniqueId);
-    HADevice(const byte* uniqueId, const uint16_t& length);
 
+    /**
+     * Constructs HADevice with the given unique ID (string).
+     * Keep the unique ID short to save the memory.
+     *
+     * @param uniqueId String with the null terminator.
+     */
+    HADevice(const char* uniqueId);
+
+    /**
+     * Constructs HADevice using the given byte array as the unique ID.
+     * It works in the same way as HADevice::setUniqueId method.
+     *
+     * @param uniqueId Bytes array that's going to be converted into the string.
+     * @param length Number of bytes in the array.
+     */
+    HADevice(const byte* uniqueId, const uint16_t length);
+
+    /**
+     * Deletes HASerializer and the availability topic if the shared availability was enabled.
+     */
+    ~HADevice();
+
+    HADevice(const HADevice&) = delete;
+    HADevice& operator=(const HADevice&) = delete;
+    HADevice(HADevice&&) = delete;
+    HADevice& operator=(HADevice&&) = delete;
+
+    /**
+     * Returns pointer to the unique ID. It can be nullptr if the device has no ID assigned.
+     */
     inline const char* getUniqueId() const
         { return _uniqueId; }
 
-    inline void setManufacturer(const char* manufacturer)
-        { _manufacturer = manufacturer; }
+    /**
+     * Returns the instance of the HASerializer used by the device.
+     * This method is used by all entities to serialize device's representation.
+     */
+    inline const HASerializer* getSerializer() const
+        { return _serializer; }
 
-    inline void setModel(const char* model)
-        { _model = model; }
+    /**
+     * Returns true if the shared availability is enabled for the device.
+     */
+    inline bool isSharedAvailabilityEnabled() const
+        { return _sharedAvailability; }
 
-    inline void setName(const char* name)
-        { _name = name; }
+    /**
+     * Returns true if the extended unique IDs feature is enabled for the device.
+     */
+    inline bool isExtendedUniqueIdsEnabled() const
+        { return _extendedUniqueIds; }
 
-    inline void setSoftwareVersion(const char* softwareVersion)
-        { _softwareVersion = softwareVersion; }
+    /**
+     * Returns availability topic generated by the HADevice::enableSharedAvailability method.
+     * It can be nullptr if the shared availability is not enabled.
+     */
+    inline const char* getAvailabilityTopic() const
+        { return _availabilityTopic; }
 
-    bool setUniqueId(const byte* uniqueId, const uint16_t& length);
-    uint16_t calculateSerializedLength() const;
-    uint16_t serialize(char* dst) const;
+    /**
+     * Returns online/offline state of the device.
+     */
+    inline bool isAvailable() const
+        { return _available; }
+
+    /**
+     * Enables the use of extended unique IDs for all registered device types.
+     * The unique ID of each device type will be prefixed with the device's ID once enabled.
+     */
+    inline void enableExtendedUniqueIds()
+        { _extendedUniqueIds = true; }
+
+    /**
+     * Sets unique ID of the device based on the given byte array.
+     * Each byte is converted into a hex string representation, so the final length of the unique ID will be twice as given.
+     *
+     * @param uniqueId Bytes array that's going to be converted into the string.
+     * @param length Number of bytes in the array.
+     * @note The unique ID can be set only once (via constructor or using this method).
+     */
+    bool setUniqueId(const byte* uniqueId, const uint16_t length);
+
+    /**
+     * Sets the "manufacturer" property that's going to be displayed in the Home Assistant.
+     *
+     * @param manufacturer Any string. Keep it short to save the memory.
+     */
+    void setManufacturer(const char* manufacturer);
+
+    /**
+     * Sets the "model" property that's going to be displayed in the Home Assistant.
+     *
+     * @param model Any string. Keep it short to save the memory.
+     */
+    void setModel(const char* model);
+
+    /**
+     * Sets the "name" property that's going to be displayed in the Home Assistant.
+     *
+     * @param name Any string. Keep it short to save the memory.
+     */
+    void setName(const char* name);
+
+    /**
+     * Sets the "software version" property that's going to be displayed in the Home Assistant.
+     *
+     * @param softwareVersion Any string. Keep it short to save the memory.
+     */
+    void setSoftwareVersion(const char* softwareVersion);
+
+    /**
+     * Sets the "configuration URL" property that's going to be used by the Home Assistant.
+     *
+     * @param url Configuration URL to publish.
+     */
+    void setConfigurationUrl(const char* url);
+
+    void setModelId(const char* modelId);
+    void setHardwareVersion(const char* hardwareVersion);
+    void setSerialNumber(const char* serialNumber);
+    void setSuggestedArea(const char* suggestedArea);
+    void setViaDevice(const char* viaDevice);
+
+    /**
+     * Adds one MQTT device connection entry (e.g. `("mac", "aa:bb:cc:dd:ee:ff")`).
+     * Connections are serialized as JSON arrays inside the discovery `dev` object.
+     *
+     * @returns Returns `false` when the internal JSON buffer would overflow.
+     */
+    bool addConnection(const char* type, const char* value);
+
+    /**
+     * Sets the `connections` array as raw JSON (e.g. [[\"mac\",\"aa:bb:cc:dd:ee:ff\"]]).
+     *
+     * This legacy escape hatch accepts only a complete JSON array of two-string
+     * connection tuples and rejects an oversized or malformed value rather than
+     * truncating a retained discovery document. Prefer addConnection().
+     *
+     * @returns false when the value is malformed or does not fit in the
+     * internal discovery buffer.
+     */
+    bool setConnectionsJson(const char* connectionsJson);
+
+    void setPayloadAvailable(const char* payload);
+    void setPayloadNotAvailable(const char* payload);
+
+    inline const char* getPayloadAvailable() const
+        { return _payloadAvailable; }
+
+    inline const char* getPayloadNotAvailable() const
+        { return _payloadNotAvailable; }
+
+    /**
+     * Sets device's availability and publishes MQTT message on the availability topic.
+     * If the device is not connected to an MQTT broker or the shared availability is not enabled then nothing happens.
+     *
+     * @param online Set to true if the device should be displayed as available in the HA panel.
+     */
+    void setAvailability(bool online);
+
+    /**
+     * Enables the shared availability feature.
+     */
+    bool enableSharedAvailability();
+
+    /**
+     * Enables MQTT LWT feature.
+     * Please note that the shared availability needs to be enabled first.
+     */
+    void enableLastWill();
+
+    /**
+     * Publishes current availability of the device on the availability topic.
+     * If the device is not connected to an MQTT broker or the shared availability is not enabled then nothing happens.
+     * This method is called by the HAMqtt when the connection to an MQTT broker is acquired.
+     */
+    void publishAvailability() const;
 
 private:
+    /// The unique ID of the device. It can be a memory allocated by HADevice::setUniqueId method.
     const char* _uniqueId;
-    const char* _manufacturer;
-    const char* _model;
-    const char* _name;
-    const char* _softwareVersion;
+
+    /// Specifies whether HADevice class owns the _uniqueId pointer.
+    bool _ownsUniqueId;
+
+    /// JSON serializer of the HADevice class. It's allocated in the constructor.
+    HASerializer* _serializer;
+
+    /// The availability topic allocated by HADevice::enableSharedAvailability method.
+    char* _availabilityTopic;
+
+    /// Specifies whether the shared availability is enabled.
+    bool _sharedAvailability;
+
+    /// Specifies whether the device is available (online / offline).
+    bool _available;
+
+    /// Specifies whether extended unique IDs feature is enabled.
+    bool _extendedUniqueIds;
+
+    const char* _payloadAvailable;
+    const char* _payloadNotAvailable;
+    static const uint16_t MaxConnectionsJsonLength = 192;
+    char _connectionsJson[MaxConnectionsJsonLength];
+    bool _hasConnections;
+    bool _connectionsPropertyRegistered;
 };
 
 #endif

src/HAMqtt.h

@@ -1,107 +1,509 @@
 #ifndef AHA_HAMQTT_H
 #define AHA_HAMQTT_H
 
+#include <Arduino.h>
 #include <Client.h>
 #include <IPAddress.h>
+#include "ArduinoHADefines.h"
+
+#define HAMQTT_CALLBACK(name) void (*name)()
+#define HAMQTT_STATE_CALLBACK(name) void (*name)(ConnectionState state)
+#define HAMQTT_MESSAGE_CALLBACK(name) void (*name)(const char* topic, const uint8_t* payload, uint16_t length)
+#define HAMQTT_DEFAULT_PORT 1883
+
+#ifdef ARDUINOHA_TEST
+class PubSubClientMock;
+#else
+#include <PubSubClient.h>
+#endif
+
+#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
+#define HAMQTT_DEFAULT_DEVICES_LIMIT 6
+#else
+#define HAMQTT_DEFAULT_DEVICES_LIMIT 24
+#endif
 
-class PubSubClient;
 class HADevice;
-class BaseDeviceType;
+class HABaseDeviceType;
+class HASerializer;
 
+#if defined(ARDUINO_API_VERSION)
+using namespace arduino;
+#endif
+
+/**
+ * This class is a wrapper for the PubSub API.
+ * It's a central point of the library where instances of all device types are stored.
+ */
 class HAMqtt
 {
 public:
-    static const uint16_t ReconnectInterval = 5000; // ms
+    /**
+     * Best-effort classification of the last disconnect or transport failure
+     * (for diagnostics; not an MQTT DISCONNECT reason code).
+     */
+    enum class DiagnosticDisconnectReason : uint8_t {
+        None = 0,
+        LoopReturnedFalse,
+        DeferredBeginPublishFailed,
+        DeferredEndPublishFailed,
+        NotConnectedDuringDeferredFlush,
+        UnderlyingPubSubStateChanged,
+        ExplicitDisconnect,
+    };
 
-    HAMqtt(Client& netClient, HADevice& device);
-    HAMqtt(const char* clientId, Client& netClient, HADevice& device);
+    static const char* diagnosticDisconnectReasonText(DiagnosticDisconnectReason reason);
+
+    enum ConnectionState {
+        StateConnecting = -5,
+        StateConnectionTimeout = -4,
+        StateConnectionLost = -3,
+        StateConnectionFailed = -2,
+        StateDisconnected = -1,
+        StateConnected = 0,
+        StateBadProtocol = 1,
+        StateBadClientId = 2,
+        StateUnavailable = 3,
+        StateBadCredentials = 4,
+        StateUnauthorized = 5
+    };
 
     /**
-     * Sets prefix for Home Assistant discovery.
-     * It needs to match prefix set in the HA admin panel.
+     * Explicit stages for safely migrating retained single-component discovery
+     * to Home Assistant device discovery.
+     */
+    enum DeviceDiscoveryMigrationState : uint8_t {
+        DeviceDiscoveryMigrationIdle = 0,
+        DeviceDiscoveryMigrationMarkersPending,
+        DeviceDiscoveryMigrationMarkersPublished,
+        DeviceDiscoveryMigrationDevicePublished,
+        DeviceDiscoveryMigrationCompleted,
+        DeviceDiscoveryMigrationRollbackPending
+    };
+
+    /**
+     * Returns existing instance (singleton) of the HAMqtt class.
+     * It may be a null pointer if the HAMqtt object was never constructed or it was destroyed.
+     */
+    inline static HAMqtt* instance()
+        { return _instance; }
+
+#ifdef ARDUINOHA_TEST
+    explicit HAMqtt(
+        PubSubClientMock* pubSub,
+        HADevice& device,
+        const uint8_t maxDevicesTypesNb = HAMQTT_DEFAULT_DEVICES_LIMIT
+    );
+#else
+    /**
+     * Creates a new instance of the HAMqtt class.
+     * Please note that only one instance of the class can be initialized at the same time.
+     *
+     * @param netClient The EthernetClient or WiFiClient that's going to be used for the network communication.
+     * @param device An instance of the HADevice class representing your device.
+     * @param maxDevicesTypesNb The maximum number of device types (sensors, switches, etc.) that you're going to implement.
+     */
+    explicit HAMqtt(
+        Client& netClient,
+        HADevice& device,
+        const uint8_t maxDevicesTypesNb = HAMQTT_DEFAULT_DEVICES_LIMIT
+    );
+#endif
+
+    /**
+     * Removes singleton of the HAMqtt class.
+     */
+    ~HAMqtt();
+    HAMqtt(const HAMqtt&) = delete;
+    HAMqtt& operator=(const HAMqtt&) = delete;
+    HAMqtt(HAMqtt&&) = delete;
+    HAMqtt& operator=(HAMqtt&&) = delete;
+
+
+    /**
+     * Sets the prefix of the Home Assistant discovery topics.
+     * It needs to match the prefix set in the HA admin panel.
      * The default prefix is "homeassistant".
+     *
+     * @param prefix The discovery topics' prefix.
      */
     inline void setDiscoveryPrefix(const char* prefix)
         { _discoveryPrefix = prefix; }
 
     /**
-     * Returns discovery prefix.
+     * Returns the discovery topics' prefix.
      */
     inline const char* getDiscoveryPrefix() const
         { return _discoveryPrefix; }
 
     /**
-     * Returns instance of the device assigned to the HAMqtt class.
+     * Sets prefix of the data topics.
+     * It may be useful if you want to pass MQTT traffic through a bridge.
+     * The default prefix is "aha".
+     *
+     * @param prefix The data topics' prefix.
      */
-    inline HADevice const* getDevice() const
-        { return (_hasDevice ? &_device : nullptr); }
+    inline void setDataPrefix(const char* prefix)
+        { _dataPrefix = prefix; }
 
     /**
-     * Sets parameters of the connection to the MQTT broker.
+     * Returns the data topics' prefix.
+     */
+    inline const char* getDataPrefix() const
+        { return _dataPrefix; }
+
+    /**
+     * Enables MQTT device discovery payloads.
+     * Single-component discovery remains the default when this is not enabled.
+     */
+    inline void enableDeviceDiscovery()
+        { _deviceDiscoveryEnabled = true; }
+
+    /**
+     * Returns true when MQTT device discovery payloads are enabled.
+     */
+    inline bool isDeviceDiscoveryEnabled() const
+        { return _deviceDiscoveryEnabled; }
+
+    /**
+     * Starts an explicit Home Assistant-safe migration from retained
+     * single-component discovery to device discovery.
+     *
+     * This method enables device discovery but does not publish anything. Call
+     * the subsequent migration methods after MQTT is connected, in order.
+     */
+    bool beginDeviceDiscoveryMigration();
+
+    /**
+     * Publishes retained migration markers to each legacy component config
+     * topic. The state advances only when every marker is published.
+     */
+    bool publishDeviceDiscoveryMigrationMarkers();
+
+    /**
+     * Publishes the retained device discovery config after all legacy markers
+     * have been published.
+     */
+    bool publishDeviceDiscoveryMigrationConfig();
+
+    /**
+     * Clears the retained legacy component config topics after the device
+     * config was published. The state advances only when every cleanup
+     * publish succeeds.
+     */
+    bool completeDeviceDiscoveryMigration();
+
+    /**
+     * Reverses a staged device discovery migration. A migration marker is
+     * published to the device discovery topic before legacy retained configs
+     * are restored and the device config is cleared.
+     * The method never runs automatically and returns to single-component
+     * discovery only after every required retained publish succeeds.
+     */
+    bool rollbackDeviceDiscoveryMigration();
+
+    /**
+     * Returns the current in-memory device discovery migration stage.
+     */
+    inline DeviceDiscoveryMigrationState getDeviceDiscoveryMigrationState() const
+        { return _deviceDiscoveryMigrationState; }
+
+    /**
+     * Returns true while an explicit device discovery migration awaits a
+     * marker, device config, or legacy-topic cleanup step.
+     */
+    inline bool isDeviceDiscoveryMigrationInProgress() const
+    {
+        return _deviceDiscoveryMigrationState != DeviceDiscoveryMigrationIdle &&
+            _deviceDiscoveryMigrationState != DeviceDiscoveryMigrationCompleted;
+    }
+
+    /**
+     * Republishes the current MQTT device discovery payload when device
+     * discovery is enabled.
+     */
+    bool publishDeviceDiscovery();
+
+    /**
+     * Sets optional `support_url` in the discovery `origin` object (must remain valid).
+     */
+    inline void setOriginSupportUrl(const char* url)
+        { _originSupportUrl = url; }
+
+    inline const char* getOriginSupportUrl() const
+        { return _originSupportUrl; }
+
+    /**
+     * Returns instance of the device assigned to the HAMqtt class.
+     * It's the same object (pointer) that was passed to the HAMqtt constructor.
+     */
+    inline HADevice const* getDevice() const
+        { return &_device; }
+
+    /**
+     * Registers a new callback method that will be called when the device receives an MQTT message.
+     * Please note that the callback is also fired by internal MQTT messages used by the library.
+     * You should always verify the topic of the received message.
+     *
+     * @param callback Callback method.
+     */
+    inline void onMessage(HAMQTT_MESSAGE_CALLBACK(callback))
+        { _messageCallback = callback; }
+
+    /**
+     * Registers a new callback method that will be called each time a connection to the MQTT broker is acquired.
+     * The callback is also fired after reconnecting to the broker.
+     * You can use this method to register topics' subscriptions.
+     *
+     * @param callback Callback method.
+     */
+    inline void onConnected(HAMQTT_CALLBACK(callback))
+        { _connectedCallback = callback; }
+
+    /**
+     * Registers a new callback method that will be called each time the connection to the MQTT broker is lost.
+     *
+     * @param callback Callback method.
+     */
+    inline void onDisconnected(HAMQTT_CALLBACK(callback))
+        { _disconnectedCallback = callback; }
+
+    /**
+     * Registers a new callback method that will be called each time the connection state changes.
+     *
+     * @param callback Callback method.
+     */
+    inline void onStateChanged(HAMQTT_STATE_CALLBACK(callback))
+        { _stateChangedCallback = callback; }
+
+    /**
+     * Returns the current state of the MQTT connection.
+     */
+    inline ConnectionState getState() const
+        { return _currentState; }
+
+    inline uint8_t getDeferredQueueCount() const
+        { return _deferredCount; }
+
+    inline uint32_t getLastLoopOkAt() const
+        { return _lastLoopOkAt; }
+
+    inline uint32_t getLastMessageAt() const
+        { return _lastMessageAt; }
+
+    inline uint32_t getLastPublishAt() const
+        { return _lastPublishAt; }
+
+    inline uint32_t getLastDisconnectAt() const
+        { return _lastDisconnectAt; }
+
+    inline DiagnosticDisconnectReason getLastDisconnectReason() const
+        { return _lastDisconnectReason; }
+
+    int getPubSubState() const;
+
+    /**
+     * Sets parameters of the MQTT connection using the IP address and port.
      * The library will try to connect to the broker in first loop cycle.
      * Please note that the library automatically reconnects to the broker if connection is lost.
      *
      * @param serverIp IP address of the MQTT broker.
      * @param serverPort Port of the MQTT broker.
-     * @param username Username for authentication.
-     * @param password Password for authentication.
+     * @param username Username for authentication. It can be nullptr if the anonymous connection needs to be performed.
+     * @param password Password for authentication. It can be nullptr if the anonymous connection needs to be performed.
      */
     bool begin(
-        const IPAddress& serverIp,
-        const uint16_t& serverPort = 1883,
+        const IPAddress serverIp,
+        const uint16_t serverPort = HAMQTT_DEFAULT_PORT,
         const char* username = nullptr,
         const char* password = nullptr
     );
 
     /**
-     * Sets parameters of the connection to the MQTT broker on default port.
+     * Sets parameters of the MQTT connection using the IP address and the default port (1883).
      * The library will try to connect to the broker in first loop cycle.
      * Please note that the library automatically reconnects to the broker if connection is lost.
      *
      * @param serverIp IP address of the MQTT broker.
-     * @param serverPort Port of the MQTT broker.
-     * @param username Username for authentication.
-     * @param password Password for authentication.
+     * @param username Username for authentication. It can be nullptr if the anonymous connection needs to be performed.
+     * @param password Password for authentication. It can be nullptr if the anonymous connection needs to be performed.
      */
     bool begin(
-        const IPAddress& serverIp,
+        const IPAddress serverIp,
         const char* username,
         const char* password
     );
 
     /**
-     * ArduinoHA's ticker.
+     * Sets parameters of the MQTT connection using the hostname and port.
+     * The library will try to connect to the broker in first loop cycle.
+     * Please note that the library automatically reconnects to the broker if connection is lost.
+     *
+     * @param serverHostname Hostname of the MQTT broker.
+     * @param serverPort Port of the MQTT broker.
+     * @param username Username for authentication. It can be nullptr if the anonymous connection needs to be performed.
+     * @param password Password for authentication. It can be nullptr if the anonymous connection needs to be performed.
+     */
+    bool begin(
+        const char* serverHostname,
+        const uint16_t serverPort = HAMQTT_DEFAULT_PORT,
+        const char* username = nullptr,
+        const char* password = nullptr
+    );
+
+    /**
+     * Sets parameters of the MQTT connection using the hostname and the default port (1883).
+     * The library will try to connect to the broker in first loop cycle.
+     * Please note that the library automatically reconnects to the broker if connection is lost.
+     *
+     * @param serverHostname Hostname of the MQTT broker.
+     * @param username Username for authentication. It can be nullptr if the anonymous connection needs to be performed.
+     * @param password Password for authentication. It can be nullptr if the anonymous connection needs to be performed.
+     */
+    bool begin(
+        const char* serverHostname,
+        const char* username,
+        const char* password
+    );
+
+    /**
+     * Closes the MQTT connection.
+     */
+    bool disconnect();
+
+    /**
+     * This method should be called periodically inside the main loop of the firmware.
+     * It's safe to call this method in some interval (like 5ms).
      */
     void loop();
 
     /**
      * Returns true if connection to the MQTT broker is established.
      */
-    bool isConnected();
+    bool isConnected() const;
+
+    /**
+     * Sets keep alive for the MQTT connection.
+     * By default it's 15 seconds.
+     *
+    * @param keepAlive Number of seconds to keep connection alive.
+     */
+    void setKeepAlive(uint16_t keepAlive);
+
+    /**
+     * Sets the buffer size for the MQTT connection.
+     * By default it's 256 bytes.
+     *
+     * @param size Size of the buffer.
+     */
+    bool setBufferSize(uint16_t size);
+
+    /**
+     * Sets minimal interval between MQTT reconnect attempts.
+     * By default it's 10000 milliseconds.
+     *
+     * @param interval Interval in milliseconds. Zero is ignored.
+     */
+    void setReconnectInterval(uint16_t interval);
+
+    /**
+     * Returns minimal interval between MQTT reconnect attempts.
+     */
+    inline uint16_t getReconnectInterval() const
+        { return _reconnectInterval; }
 
     /**
      * Adds a new device's type to the MQTT.
      * Each time the connection with MQTT broker is acquired, the HAMqtt class
      * calls "onMqttConnected" method in all devices' types instances.
      *
-     * @param deviceType Instance of the device's type (eg. HATriggers).
+     * @note The HAMqtt class doesn't take ownership of the given pointer.
+     * @param deviceType Instance of the device's type (HASwitch, HABinarySensor, etc.).
      */
-    void addDeviceType(BaseDeviceType* deviceType);
+    bool addDeviceType(HABaseDeviceType* deviceType);
 
     /**
-     * Publishes MQTT message with given topic and payload.
-     * Message won't be published if connection with MQTT broker is not established.
+     * Removes a destroyed entity from the connection registry.
+     * The MQTT instance does not own entity lifetimes.
+     */
+    bool removeDeviceType(HABaseDeviceType* deviceType);
+
+    /**
+     * Number of entities currently registered for connection callbacks.
+     */
+    inline uint8_t getRegisteredDeviceTypeCount() const
+        { return _devicesTypesNb; }
+
+    /**
+     * Maximum number of entities that can be registered in this HAMqtt instance.
+     */
+    inline uint8_t getDeviceTypeLimit() const
+        { return _maxDevicesTypesNb; }
+
+    /**
+     * Number of registrations dropped because the configured entity limit was reached.
+     */
+    inline uint16_t getDeviceTypeRegistrationFailures() const
+        { return _deviceTypeRegistrationFailures; }
+
+    /**
+     * Publishes the MQTT message with given topic and payload.
+     * Message won't be published if the connection with the MQTT broker is not established.
      * In this case method returns false.
      *
-     * @param topic Topic to publish.
-     * @param payload Payload to publish (it may be empty const char).
-     * @param retained Determines whether message should be retained.
+     * While handling an inbound MQTT message (see isProcessingMessage()), a successful
+     * return means the message was queued for send after dispatch completes, not that it
+     * was already transmitted. Outside that context, behavior is unchanged.
+     *
+     * @param topic The topic to publish.
+     * @param payload The payload to publish (it may be empty const char).
+     * @param retained Specifies whether message should be retained.
      */
     bool publish(const char* topic, const char* payload, bool retained = false);
 
+    /**
+     * Begins publishing of a message with the given properties.
+     * When this method returns true the payload can be written using HAMqtt::writePayload method.
+     *
+     * @param topic Topic of the published message.
+     * @param payloadLength Length of the payload (bytes) that's going to be published.
+     * @param retained Specifies whether the published message should be retained.
+     */
     bool beginPublish(const char* topic, uint16_t payloadLength, bool retained = false);
-    bool writePayload(const char* data, uint16_t length);
-    bool writePayload_P(const char* src);
+
+    /**
+     * Writes given string to the TCP stream.
+     * Please note that before writing any data the HAMqtt::beginPublish method
+     * needs to be called.
+     *
+     * @param data The string to publish.
+     * @param length Length of the data (bytes).
+     */
+    bool writePayload(const char* data, const uint16_t length);
+
+    /**
+     * Writes given data to the TCP stream.
+     * Please note that before writing any data the HAMqtt::beginPublish method
+     * needs to be called.
+     *
+     * @param data The data to publish.
+     * @param length Length of the data (bytes).
+     */
+    bool writePayload(const uint8_t* data, const uint16_t length);
+
+    /**
+     * Writes given progmem data to the TCP stream.
+     * Please note that before writing any data the HAMqtt::beginPublish method
+     * needs to be called.
+     *
+     * @param data Progmem data to publish.
+     */
+    bool writePayload(const __FlashStringHelper* data);
+
+    /**
+     * Finishes publishing of a message.
+     * After calling this method the message will be processed by the broker.
+     */
     bool endPublish();
 
     /**
@@ -112,20 +514,89 @@ public:
      * Please note that you need to subscribe topic each time the connection
      * with the broker is acquired.
      *
-     * @param topic Topic to subscribe
+     * @param topic Topic to subscribe.
      */
     bool subscribe(const char* topic);
 
+    /**
+     * Enables the last will message that will be produced when the device disconnects from the broker.
+     * If you want to change availability of the device in Home Assistant panel
+     * please use enableLastWill() method from the HADevice class instead.
+     *
+     * @param lastWillTopic The topic to publish.
+     * @param lastWillMessage The message (payload) to publish.
+     * @param lastWillRetain Specifies whether the published message should be retained.
+     */
+    inline void setLastWill(
+        const char* lastWillTopic,
+        const char* lastWillMessage,
+        bool lastWillRetain
+    ) {
+        _lastWillTopic = lastWillTopic;
+        _lastWillMessage = lastWillMessage;
+        _lastWillRetain = lastWillRetain;
+    }
+
     /**
      * Processes MQTT message received from the broker (subscription).
      *
+     * @note Do not use this method on your own. It's only for the internal purpose.
      * @param topic Topic of the message.
      * @param payload Content of the message.
      * @param length Length of the message.
      */
-    void processMessage(char* topic, uint8_t* payload, uint16_t length);
+    void processMessage(const char* topic, const uint8_t* payload, uint16_t length);
+
+    /**
+     * True while handling an inbound MQTT message (user onMessage and device onMqttMessage).
+     * Publish attempts in this window are queued and flushed when dispatch completes.
+     */
+    inline bool isProcessingMessage() const
+        { return _messageDispatchDepth > 0; }
+
+#ifdef ARDUINOHA_TEST
+    inline uint8_t getDevicesTypesNb() const
+        { return _devicesTypesNb; }
+
+    inline HABaseDeviceType** getDevicesTypes() const
+        { return _devicesTypes; }
+
+    inline uint16_t getDeferredPublishEnqueueCountForTest() const
+        { return _deferredPublishEnqueueCountForTest; }
+
+    inline void resetDeferredPublishTestCounters()
+    {
+        _deferredPublishEnqueueCountForTest = 0;
+        _deferredFlushFailedForTest = false;
+        _lastDeferredFlushErrorForTest = 0;
+    }
+
+    inline uint8_t getPendingDeferredPublishesForTest() const
+        { return _deferredCount; }
+
+    inline bool hasDeferredFlushFailureForTest() const
+        { return _deferredFlushFailedForTest; }
+
+    inline uint8_t getLastDeferredFlushErrorForTest() const
+        { return _lastDeferredFlushErrorForTest; }
+
+    inline bool didDeferredFlushFailDueToDisconnectForTest() const
+        { return _lastDeferredFlushErrorForTest == 1; }
+
+    inline bool didDeferredFlushFailAtBeginPublishForTest() const
+        { return _lastDeferredFlushErrorForTest == 2; }
+
+    inline bool didDeferredFlushFailAtEndPublishForTest() const
+        { return _lastDeferredFlushErrorForTest == 3; }
+#endif
 
 private:
+    /// Default interval between MQTT reconnect attempts (milliseconds).
+    static const uint16_t DefaultReconnectInterval = 10000;
+
+    /// Living instance of the HAMqtt class. It can be nullptr.
+    static HAMqtt* _instance;
+
     /**
      * Attempts to connect to the MQTT broker.
      * The method uses properties passed to the "begin" method.
@@ -135,21 +606,206 @@ private:
     /**
      * This method is called each time the connection with MQTT broker is acquired.
      */
-    void onConnected();
+    void onConnectedLogic();
 
-    Client& _netClient;
-    HADevice& _device;
-    bool _hasDevice;
-    bool _initialized;
-    const char* _discoveryPrefix;
+    bool publishDeviceDiscoveryPayload(HABaseDeviceType* removalType = nullptr);
+
+    HASerializer* buildDeviceDiscoveryComponentSerializer(
+        HABaseDeviceType* deviceType,
+        HABaseDeviceType* removalType
+    );
+
+    bool clearDeviceDiscoveryConfig();
+
+    bool publishDeviceDiscoveryMigrationMarker(HABaseDeviceType* deviceType);
+
+    /**
+     * Marks the retained device discovery config for Home Assistant's reverse
+     * migration protocol before restoring legacy component configs.
+     */
+    bool publishDeviceDiscoveryMigrationMarker();
+
+    /**
+     * Removes a component from a device discovery payload using Home
+     * Assistant's required platform-only marker, followed by a compacted
+     * bundle when another component remains.
+     */
+    bool removeDeviceDiscoveryComponent(HABaseDeviceType* deviceType);
+
+    /**
+     * Re-adds (or refreshes) a component in the current device discovery
+     * payload.
+     */
+    bool republishDeviceDiscoveryComponent(HABaseDeviceType* deviceType);
+
+    /**
+     * Sets the state of the MQTT connection.
+     */
+    void setState(ConnectionState state);
+
+    struct DeferredPublishMessage {
+        char* topic;
+        uint8_t* payload;
+        uint16_t length;
+        bool retained;
+    };
+
+    struct DeferredPublishBuilder {
+        bool active;
+        bool valid;
+        char* topic;
+        uint8_t* payload;
+        uint16_t expectedLength;
+        uint16_t writtenLength;
+        bool retained;
+    };
+
+    enum DeferredFlushError {
+        DeferredFlushErrorNone = 0,
+        DeferredFlushErrorNotConnected,
+        DeferredFlushErrorBeginPublish,
+        DeferredFlushErrorEndPublish
+    };
+
+    static const uint8_t DeferredQueueCapacity = 8;
+
+    bool enqueueDeferredPublish(
+        const char* topic,
+        const uint8_t* payload,
+        uint16_t length,
+        bool retained
+    );
+
+    void clearDeferredMessage(DeferredPublishMessage& msg);
+
+    void clearDeferredQueue();
+
+    void clearDeferredBuilder();
+
+    /**
+     * Sends queued publishes in order. On transport failure, stops and leaves the
+     * remaining queue intact for a later retry (e.g. from loop()).
+     */
+    bool flushDeferredPublishes();
+
+    /**
+     * PubSubClient snapshot when a direct publish step fails (header or endPublish).
+     */
+    String formatDirectPublishFailureDiagnostics(bool hamqttConnectedBefore, int pubsubStateBefore) const;
+
+    // Buffer direct MQTT streaming writes so serializers do not issue hundreds
+    // of tiny TCP writes while a PubSubClient publish is open.
+    static const uint16_t DirectPublishBufferSize = 128;
+    bool flushDirectPublishBuffer();
+    bool appendDirectPublishPayload(const uint8_t* data, uint16_t length);
+    bool appendDirectPublishProgmemPayload(const __FlashStringHelper* src);
+    void clearDirectPublishBuffer();
+    void abortDirectPublish();
+
+#ifdef ARDUINOHA_TEST
+    PubSubClientMock* _mqtt;
+#else
+    /// Storage for the PubSubClient instance used in production builds.
+    PubSubClient _mqttStorage;
+
+    /// Pointer to the active MQTT client implementation.
     PubSubClient* _mqtt;
-    IPAddress* _serverIp;
-    uint16_t _serverPort;
+#endif
+
+    uint8_t _directPublishBuffer[DirectPublishBufferSize];
+    uint16_t _directPublishBufferLength;
+    bool _directPublishActive;
+
+    /// Instance of the HADevice passed to the constructor.
+    const HADevice& _device;
+
+    /// The callback method that will be called when an MQTT message is received.
+    HAMQTT_MESSAGE_CALLBACK(_messageCallback);
+
+    /// The callback method that will be called when the MQTT connection is acquired.
+    HAMQTT_CALLBACK(_connectedCallback);
+
+    /// The callback method that will be called when the MQTT connection is lost.
+    HAMQTT_CALLBACK(_disconnectedCallback);
+
+    /// The callback method that will be called when the MQTT connection state changes.
+    HAMQTT_STATE_CALLBACK(_stateChangedCallback);
+
+    /// Specifies whether the HAMqtt::begin method was ever called.
+    bool _initialized;
+
+    /// Teh discovery prefix that's used for the configuration messages.
+    const char* _discoveryPrefix;
+
+    /// The data prefix that's used for publishing data messages.
+    const char* _dataPrefix;
+
+    /// Enables MQTT device discovery mode when set to true.
+    bool _deviceDiscoveryEnabled;
+
+    /// Current in-memory stage of an explicit device discovery migration.
+    DeviceDiscoveryMigrationState _deviceDiscoveryMigrationState;
+
+    const char* _originSupportUrl;
+
+    /// The username used for the authentication. It's set in the HAMqtt::begin method.
     const char* _username;
+
+    /// The password used for the authentication. It's set in the HAMqtt::begin method.
     const char* _password;
+
+    /// Time of the last connection attemps (milliseconds since boot).
     uint32_t _lastConnectionAttemptAt;
+
+    /// Interval between MQTT reconnect attempts (milliseconds).
+    uint16_t _reconnectInterval;
+
+    /// The amount of registered devices types.
     uint8_t _devicesTypesNb;
-    BaseDeviceType** _devicesTypes;
+
+    /// The maximum amount of devices types that can be registered.
+    uint8_t _maxDevicesTypesNb;
+
+    /// Pointers of all registered devices types (array of pointers).
+    HABaseDeviceType** _devicesTypes;
+
+    /// The last will topic set by HAMqtt::setLastWill
+    const char* _lastWillTopic;
+
+    /// Count of entity registrations rejected because the configured cap was full.
+    uint16_t _deviceTypeRegistrationFailures;
+
+    /// The last will message set by HAMqtt::setLastWill
+    const char* _lastWillMessage;
+
+    /// The last will retain set by HAMqtt::setLastWill
+    bool _lastWillRetain;
+
+    /// The last known state of the MQTT connection.
+    ConnectionState _currentState;
+
+    uint32_t _lastLoopOkAt;
+    uint32_t _lastMessageAt;
+    uint32_t _lastPublishAt;
+    uint32_t _lastDisconnectAt;
+    DiagnosticDisconnectReason _lastDisconnectReason;
+
+    /// Nesting depth for inbound message dispatch (processMessage).
+    uint8_t _messageDispatchDepth;
+
+    DeferredPublishMessage _deferredQueue[DeferredQueueCapacity];
+    uint8_t _deferredHead;
+    uint8_t _deferredCount;
+
+    DeferredPublishBuilder _deferredBuilder;
+
+#ifdef ARDUINOHA_TEST
+    uint16_t _deferredPublishEnqueueCountForTest = 0;
+    bool _deferredFlushFailedForTest = false;
+    uint8_t _lastDeferredFlushErrorForTest = 0;
+#endif
+
+    friend class HABaseDeviceType;
 };
 
 #endif

src/HAUtils.cpp

@@ -1,79 +0,0 @@
-#include <Arduino.h>
-
-#include "HAUtils.h"
-
-bool HAUtils::endsWith(const char* str, const char* suffix)
-{
-    if (str == nullptr || suffix == nullptr) {
-        return false;
-    }
-
-    const uint16_t& lenstr = strlen(str);
-    const uint16_t& lensuffix = strlen(suffix);
-
-    if (lensuffix > lenstr) {
-        return false;
-    }
-
-    return (strncmp(str + lenstr - lensuffix, suffix, lensuffix) == 0);
-}
-
-void HAUtils::byteArrayToStr(
-    char* dst,
-    const byte* src,
-    const uint16_t& length
-)
-{
-    const uint16_t& finalLength = (length * 2);
-    static const char map[] PROGMEM = {"0123456789abcdef"};
-
-    for (uint8_t i = 0; i < length; i++) {
-        dst[i*2] = pgm_read_byte(&map[((char)src[i] & 0XF0) >> 4]);
-        dst[i*2+1] = pgm_read_byte(&map[((char)src[i] & 0x0F)]);
-    }
-
-    dst[finalLength] = '\0';
-}
-
-char* HAUtils::byteArrayToStr(
-    const byte* src,
-    const uint16_t& length
-)
-{
-    char* dst = (char*)malloc((length * 2) + 1); // include null terminator
-    byteArrayToStr(dst, src, length);
-
-    return dst;
-}
-
-uint8_t HAUtils::getValueTypeLength(const ValueType& type)
-{
-    switch(type) {
-        case ValueTypeUint8:
-            return sizeof(uint8_t);
-
-        case ValueTypeUint16:
-            return sizeof(uint16_t);
-
-        case ValueTypeUint32:
-            return sizeof(uint32_t);
-
-        case ValueTypeInt8:
-            return sizeof(int8_t);
-
-        case ValueTypeInt16:
-            return sizeof(int16_t);
-
-        case ValueTypeInt32:
-            return sizeof(int32_t);
-
-        case ValueTypeDouble:
-            return sizeof(double);
-
-        case ValueTypeFloat:
-            return sizeof(float);
-
-        default:
-            return 0;
-    }
-}

src/HAUtils.h

@@ -1,58 +0,0 @@
-#ifndef AHA_HAUTILS_H
-#define AHA_HAUTILS_H
-
-#include <Arduino.h>
-
-class HAUtils
-{
-public:
-    enum ValueType {
-        ValueTypeUnknown = -1,
-        ValueTypeUint8,
-        ValueTypeUint16,
-        ValueTypeUint32,
-        ValueTypeInt8,
-        ValueTypeInt16,
-        ValueTypeInt32,
-        ValueTypeDouble,
-        ValueTypeFloat
-    };
-
-    static bool endsWith(
-        const char* str,
-        const char* suffi
-    );
-    static void byteArrayToStr(
-        char* dst,
-        const byte* src,
-        const uint16_t& length
-    );
-    static char* byteArrayToStr(
-        const byte* src,
-        const uint16_t& length
-    );
-
-    template <typename A, typename B >
-    static bool compareType(A a, B b) { return false; }
-
-    template <typename A, typename B >
-    static bool compareType(A a, A b) { return true; }
-
-    template <typename T>
-    static ValueType determineValueType() {
-        if (compareType<T, uint8_t>(0, (uint8_t)0)) return ValueTypeUint8;
-        else if (compareType<T, uint16_t>(0, (uint16_t)0)) return ValueTypeUint16;
-        else if (compareType<T, uint32_t>(0, (uint32_t)0)) return ValueTypeUint32;
-        else if (compareType<T, int8_t>(0, (int8_t)0)) return ValueTypeInt8;
-        else if (compareType<T, int16_t>(0, (int16_t)0)) return ValueTypeInt16;
-        else if (compareType<T, int32_t>(0, (int32_t)0)) return ValueTypeInt32;
-        else if (compareType<T, double>(0, (double)0)) return ValueTypeDouble;
-        else if (compareType<T, float>(0, (float)0)) return ValueTypeFloat;
-
-        return ValueTypeUnknown;
-    }
-
-    static uint8_t getValueTypeLength(const ValueType& type);
-};
-
-#endif

src/device-types/BaseDeviceType.cpp

@@ -1,70 +0,0 @@
-#include "BaseDeviceType.h"
-#include "../HAMqtt.h"
-#include "../HADevice.h"
-
-BaseDeviceType::BaseDeviceType(
-    HAMqtt& mqtt,
-    const char* componentName,
-    const char* name
-) :
-    _mqtt(mqtt),
-    _componentName(componentName),
-    _name(name),
-    _availability(AvailabilityDefault)
-{
-    _mqtt.addDeviceType(this);
-}
-
-BaseDeviceType::~BaseDeviceType()
-{
-
-}
-
-void BaseDeviceType::setAvailability(bool online)
-{
-    _availability = (online ? AvailabilityOnline : AvailabilityOffline);
-    publishAvailability();
-}
-
-void BaseDeviceType::publishAvailability()
-{
-    if (_availability == AvailabilityDefault ||
-            !_mqtt.isConnected() ||
-            strlen(_name) == 0 ||
-            strlen(_componentName) == 0) {
-        return;
-    }
-
-    const uint16_t& topicSize = DeviceTypeSerializer::calculateTopicLength(
-        mqtt(),
-        _componentName,
-        _name,
-        DeviceTypeSerializer::AvailabilityTopic
-    );
-    if (topicSize == 0) {
-        return;
-    }
-
-    char topic[topicSize];
-    DeviceTypeSerializer::generateTopic(
-        mqtt(),
-        topic,
-        _componentName,
-        _name,
-        DeviceTypeSerializer::AvailabilityTopic
-    );
-
-    if (strlen(topic) == 0) {
-        return;
-    }
-
-    mqtt()->publish(
-        topic,
-        (
-            _availability == AvailabilityOnline ?
-            DeviceTypeSerializer::Online :
-            DeviceTypeSerializer::Offline
-        ),
-        true
-    );
-}

src/device-types/BaseDeviceType.h

@@ -1,63 +0,0 @@
-#ifndef AHA_BASEDEVICETYPE_H
-#define AHA_BASEDEVICETYPE_H
-
-#include <stdint.h>
-
-#include "DeviceTypeSerializer.h"
-
-class HAMqtt;
-
-class BaseDeviceType
-{
-public:
-    BaseDeviceType(
-        HAMqtt& mqtt,
-        const char* componentName,
-        const char* name
-    );
-    virtual ~BaseDeviceType();
-
-    inline bool isOnline() const
-        { return (_availability == AvailabilityOnline); }
-
-    virtual void setAvailability(bool online);
-
-protected:
-    inline HAMqtt* mqtt() const
-        { return &_mqtt; }
-
-    inline const char* name() const
-        { return _name; }
-
-    inline const char* componentName() const
-        { return _componentName; }
-
-    inline bool isAvailabilityConfigured() const
-        { return (_availability != AvailabilityDefault); }
-
-    virtual void onMqttConnected() = 0;
-    virtual void onMqttMessage(
-        const char* topic,
-        const uint8_t* payload,
-        const uint16_t& length
-    ) { };
-
-    virtual void publishAvailability();
-
-    const char* const _componentName;
-    const char* const _name;
-
-private:
-    enum Availability {
-        AvailabilityDefault = 0,
-        AvailabilityOnline,
-        AvailabilityOffline
-    };
-
-    HAMqtt& _mqtt;
-    Availability _availability;
-
-    friend class HAMqtt;
-};
-
-#endif

src/device-types/DeviceTypeSerializer.cpp

@@ -1,266 +0,0 @@
-#include <Arduino.h>
-
-#include "DeviceTypeSerializer.h"
-#include "../HAMqtt.h"
-#include "../HADevice.h"
-
-static const char CharSlash[] PROGMEM = {"/"};
-static const char CharUnderscore[] PROGMEM = {"_"};
-static const char CharQuotation[] PROGMEM = {"\""};
-
-const char* DeviceTypeSerializer::ConfigTopic = "config";
-const char* DeviceTypeSerializer::EventTopic = "event";
-const char* DeviceTypeSerializer::AvailabilityTopic = "avail";
-const char* DeviceTypeSerializer::StateTopic = "state";
-const char* DeviceTypeSerializer::CommandTopic = "cmd";
-const char* DeviceTypeSerializer::Online = "online";
-const char* DeviceTypeSerializer::Offline = "offline";
-const char* DeviceTypeSerializer::StateOn = "ON";
-const char* DeviceTypeSerializer::StateOff = "OFF";
-
-uint16_t DeviceTypeSerializer::calculateTopicLength(
-    const HAMqtt* mqtt,
-    const char* component,
-    const char* objectId,
-    const char* suffix,
-    bool includeNullTerminator
-)
-{
-    const char* prefix = mqtt->getDiscoveryPrefix();
-    if (prefix == nullptr) {
-        return 0;
-    }
-
-    uint16_t size =
-        strlen(prefix) + 1 + // with slash
-        strlen(component) + 1 + // with slash
-        strlen(suffix);
-
-    if (objectId != nullptr) {
-        size += strlen(objectId) + 1; // with slash
-    } else {
-        size += 1; // slash
-    }
-
-    if (mqtt->getDevice() != nullptr) {
-        size += strlen(mqtt->getDevice()->getUniqueId()) + 1; // with slash
-    }
-
-    if (includeNullTerminator) {
-        size += 1;
-    }
-
-    return size;
-}
-
-uint16_t DeviceTypeSerializer::generateTopic(
-    const HAMqtt* mqtt,
-    char* output,
-    const char* component,
-    const char* objectId,
-    const char* suffix
-)
-{
-    const char* prefix = mqtt->getDiscoveryPrefix();
-    strcpy(output, prefix);
-    strcat_P(output, CharSlash);
-    strcat(output, component);
-    strcat_P(output, CharSlash);
-
-    if (mqtt->getDevice() != nullptr) {
-        strcat(output, mqtt->getDevice()->getUniqueId());
-        strcat_P(output, CharSlash);
-    }
-
-    strcat(output, objectId);
-    strcat_P(output, CharSlash);
-    strcat(output, suffix);
-    return strlen(output) + 1; // size with null terminator
-}
-
-uint16_t DeviceTypeSerializer::calculateBaseJsonDataSize()
-{
-    return 2; // opening and closing brackets of the JSON data
-}
-
-uint16_t DeviceTypeSerializer::calculateNameFieldSize(const char* name)
-{
-    if (name == nullptr) {
-        return 0;
-    }
-
-    // Field format: ,"name":"[NAME]"
-    return strlen(name) + 10; // 10 - length of the JSON decorators for this field
-}
-
-uint16_t DeviceTypeSerializer::calculateUniqueIdFieldSize(
-    const HADevice* device,
-    const char* name
-)
-{
-    if (device == nullptr || name == nullptr) {
-        return 0;
-    }
-
-    // Field format: ,"uniq_id":"[DEVICE ID]_[NAME]"
-    return (
-        strlen(device->getUniqueId()) +
-        strlen(name) +
-        14 // 14 - length of the JSON decorators for this field
-    );
-}
-
-uint16_t DeviceTypeSerializer::calculateAvailabilityFieldSize(
-    const HAMqtt* mqtt,
-    const char* componentName,
-    const char* name
-)
-{
-    if (mqtt == nullptr || componentName == nullptr || name == nullptr) {
-        return 0;
-    }
-
-    const uint16_t& availabilityTopicLength = calculateTopicLength(
-        mqtt,
-        componentName,
-        name,
-        AvailabilityTopic,
-        false
-    );
-
-    if (availabilityTopicLength == 0) {
-        return 0;
-    }
-
-    // Field format: ,"avty_t":"[TOPIC]"
-    return availabilityTopicLength + 12; // 12 - length of the JSON decorators for this field
-}
-
-uint16_t DeviceTypeSerializer::calculateDeviceFieldSize(
-    const char* serializedDevice
-)
-{
-    if (serializedDevice == nullptr) {
-        return 0;
-    }
-
-    // Field format: ,"dev":[DEVICE]
-    return strlen(serializedDevice) + 7; // 7 - length of the JSON decorators for this field
-}
-
-void DeviceTypeSerializer::mqttWriteBeginningJson(HAMqtt* mqtt)
-{
-    if (mqtt == nullptr) {
-        return;
-    }
-
-    static const char Data[] PROGMEM = {"{"};
-    mqtt->writePayload_P(Data);
-}
-
-void DeviceTypeSerializer::mqttWriteEndJson(HAMqtt* mqtt)
-{
-    if (mqtt == nullptr) {
-        return;
-    }
-
-    static const char Data[] PROGMEM = {"}"};
-    mqtt->writePayload_P(Data);
-}
-
-void DeviceTypeSerializer::mqttWriteConstCharField(
-    HAMqtt* mqtt,
-    const char* prefix,
-    const char* value
-)
-{
-    if (mqtt == nullptr || prefix == nullptr || value == nullptr) {
-        return;
-    }
-
-    mqtt->writePayload_P(prefix);
-    mqtt->writePayload(value, strlen(value));
-    mqtt->writePayload_P(CharQuotation);
-}
-
-void DeviceTypeSerializer::mqttWriteNameField(HAMqtt* mqtt, const char* name)
-{
-    if (mqtt == nullptr || name == nullptr) {
-        return;
-    }
-
-    static const char Prefix[] PROGMEM = {",\"name\":\""};
-    mqttWriteConstCharField(mqtt, Prefix, name);
-}
-
-void DeviceTypeSerializer::mqttWriteUniqueIdField(
-    HAMqtt* mqtt,
-    const char* name
-)
-{
-    if (mqtt == nullptr || name == nullptr) {
-        return;
-    }
-
-    static const char Prefix[] PROGMEM = {",\"uniq_id\":\""};
-
-    uint8_t uniqueIdLength = strlen(name) + strlen(mqtt->getDevice()->getUniqueId()) + 2; // underscore and null temrinator
-    char uniqueId[uniqueIdLength];
-    strcpy(uniqueId, name);
-    strcat_P(uniqueId, CharUnderscore);
-    strcat(uniqueId, mqtt->getDevice()->getUniqueId());
-
-    mqttWriteConstCharField(mqtt, Prefix, uniqueId);
-}
-
-void DeviceTypeSerializer::mqttWriteAvailabilityField(
-    HAMqtt* mqtt,
-    const char* componentName,
-    const char* name
-)
-{
-    if (mqtt == nullptr || componentName == nullptr || name == nullptr) {
-        return;
-    }
-
-    const uint16_t& topicSize = calculateTopicLength(
-        mqtt,
-        componentName,
-        name,
-        AvailabilityTopic
-    );
-    if (topicSize == 0) {
-        return;
-    }
-
-    char availabilityTopic[topicSize];
-    generateTopic(
-        mqtt,
-        availabilityTopic,
-        componentName,
-        name,
-        AvailabilityTopic
-    );
-
-    if (strlen(availabilityTopic) == 0) {
-        return;
-    }
-
-    static const char Prefix[] PROGMEM = {",\"avty_t\":\""};
-    mqttWriteConstCharField(mqtt, Prefix, availabilityTopic);
-}
-
-void DeviceTypeSerializer::mqttWriteDeviceField(
-    HAMqtt* mqtt,
-    const char* serializedDevice
-)
-{
-    if (mqtt == nullptr || serializedDevice == nullptr) {
-        return;
-    }
-
-    static const char Data[] PROGMEM = {",\"dev\":"};
-
-    mqtt->writePayload_P(Data);
-    mqtt->writePayload(serializedDevice, strlen(serializedDevice));
-}

src/device-types/DeviceTypeSerializer.h

@@ -1,98 +0,0 @@
-#ifndef AHA_DEVICETYPESERIALIZER_H
-#define AHA_DEVICETYPESERIALIZER_H
-
-#include <stdint.h>
-
-class HAMqtt;
-class HADevice;
-
-class DeviceTypeSerializer
-{
-public:
-    static const char* ConfigTopic;
-    static const char* EventTopic;
-    static const char* AvailabilityTopic;
-    static const char* StateTopic;
-    static const char* CommandTopic;
-    static const char* Online;
-    static const char* Offline;
-    static const char* StateOn;
-    static const char* StateOff;
-
-    /**
-     * Calculates length of the topic with given parameters.
-     * Topic format: [discovery prefix]/[component]/[objectId]/[suffix]
-     *
-     * @param component
-     * @param objectId
-     * @param suffix
-     * @param includeNullTerminator
-     */
-    static uint16_t calculateTopicLength(
-        const HAMqtt* mqtt,
-        const char* component,
-        const char* objectId,
-        const char* suffix,
-        bool includeNullTerminator = true
-    );
-
-    /**
-     * Generates topic and saves it to the given buffer.
-     * Please note that size of the buffer must be calculated by `calculateTopicLength` method first.
-     * Topic format: [discovery prefix]/[component]/[objectId]/[suffix]
-     *
-     * @param output
-     * @param component
-     * @param objectId
-     * @param suffix
-     * @param includeNullTerminator
-     */
-    static uint16_t generateTopic(
-        const HAMqtt* mqtt,
-        char* output,
-        const char* component,
-        const char* objectId,
-        const char* suffix
-    );
-
-    static uint16_t calculateBaseJsonDataSize();
-    static uint16_t calculateNameFieldSize(
-        const char* name
-    );
-    static uint16_t calculateUniqueIdFieldSize(
-        const HADevice* device,
-        const char* name
-    );
-    static uint16_t calculateAvailabilityFieldSize(
-        const HAMqtt* mqtt,
-        const char* componentName,
-        const char* name
-    );
-    static uint16_t calculateDeviceFieldSize(
-        const char* serializedDevice
-    );
-
-    static void mqttWriteBeginningJson(HAMqtt* mqtt);
-    static void mqttWriteEndJson(HAMqtt* mqtt);
-    static void mqttWriteConstCharField(
-        HAMqtt* mqtt,
-        const char* prefix,
-        const char* value
-    );
-    static void mqttWriteNameField(HAMqtt* mqtt, const char* name);
-    static void mqttWriteUniqueIdField(
-        HAMqtt* mqtt,
-        const char* name
-    );
-    static void mqttWriteAvailabilityField(
-        HAMqtt* mqtt,
-        const char* componentName,
-        const char* name
-    );
-    static void mqttWriteDeviceField(
-        HAMqtt* mqtt,
-        const char* serializedDevice
-    );
-};
-
-#endif

src/device-types/HABaseDeviceType.cpp

@@ -0,0 +1,667 @@
+#include "HABaseDeviceType.h"
+#include "../HAMqtt.h"
+#include "../HADevice.h"
+#include "../utils/HAUtils.h"
+#include "../utils/HADictionary.h"
+#include "../utils/HASerializer.h"
+#include <string.h>
+
+HABaseDeviceType* HABaseDeviceType::_firstInstance = nullptr;
+
+void HABaseDeviceType::registerAllWith(HAMqtt& mqttInstance)
+{
+    for (HABaseDeviceType* entity = _firstInstance; entity; entity = entity->_nextInstance) {
+        mqttInstance.addDeviceType(entity);
+    }
+}
+
+HABaseDeviceType::HABaseDeviceType(
+    const __FlashStringHelper* componentName,
+    const char* uniqueId
+) :
+    _componentName(componentName),
+    _uniqueId(uniqueId),
+    _name(nullptr),
+    _objectId(nullptr),
+    _defaultEntityId(nullptr),
+    _entityCategory(nullptr),
+    _serializer(nullptr),
+    _hasEnabledByDefault(false),
+    _enabledByDefault(true),
+    _entityPicture(nullptr),
+    _hasQos(false),
+    _qosNumeric(),
+    _encoding(nullptr),
+    _payloadAvailable(nullptr),
+    _payloadNotAvailable(nullptr),
+    _availabilityMode(nullptr),
+    _availabilityList(),
+    _deviceDiscoveryRemoved(false),
+    _availability(AvailabilityDefault),
+    _nextInstance(_firstInstance)
+{
+    _firstInstance = this;
+    if (HAMqtt* mqttInstance = mqtt()) {
+        mqttInstance->addDeviceType(this);
+    }
+}
+
+HABaseDeviceType::~HABaseDeviceType()
+{
+    if (_firstInstance == this) {
+        _firstInstance = _nextInstance;
+    } else {
+        HABaseDeviceType* previous = _firstInstance;
+        while (previous && previous->_nextInstance != this) {
+            previous = previous->_nextInstance;
+        }
+        if (previous) {
+            previous->_nextInstance = _nextInstance;
+        }
+    }
+
+    if (HAMqtt* mqttInstance = mqtt()) {
+        mqttInstance->removeDeviceType(this);
+    }
+
+    destroySerializer();
+}
+
+void HABaseDeviceType::setAvailability(bool online)
+{
+    _availability = (online ? AvailabilityOnline : AvailabilityOffline);
+    publishAvailability();
+}
+
+bool HABaseDeviceType::removeFromDiscovery()
+{
+    HAMqtt* mqttInstance = mqtt();
+    if (!mqttInstance) {
+        return false;
+    }
+
+    if (mqttInstance->isDeviceDiscoveryEnabled() && supportsDeviceDiscovery()) {
+        return mqttInstance->removeDeviceDiscoveryComponent(this);
+    }
+
+    return removeSingleComponentDiscovery();
+}
+
+bool HABaseDeviceType::removeSingleComponentDiscovery()
+{
+    HAMqtt* mqttInstance = mqtt();
+    if (!mqttInstance) {
+        return false;
+    }
+
+    const uint16_t topicLength = HASerializer::calculateConfigTopicLength(
+        componentName(),
+        uniqueId()
+    );
+    if (topicLength == 0) {
+        return false;
+    }
+
+    char topic[topicLength];
+    if (!HASerializer::generateConfigTopic(topic, componentName(), uniqueId())) {
+        return false;
+    }
+
+    destroySerializer();
+    if (!mqttInstance->beginPublish(topic, 0, true)) {
+        return false;
+    }
+
+    return mqttInstance->endPublish();
+}
+
+bool HABaseDeviceType::republishDiscovery()
+{
+    HAMqtt* mqttInstance = mqtt();
+    if (!mqttInstance) {
+        return false;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        return publishConfig();
+    }
+
+    return mqttInstance->republishDeviceDiscoveryComponent(this);
+}
+
+HAMqtt* HABaseDeviceType::mqtt()
+{
+    return HAMqtt::instance();
+}
+
+void HABaseDeviceType::subscribeTopic(
+    const char* uniqueId,
+    const __FlashStringHelper* topic
+)
+{
+    const uint16_t topicLength = HASerializer::calculateDataTopicLength(
+        uniqueId,
+        topic
+    );
+    if (topicLength == 0) {
+        return;
+    }
+
+    char fullTopic[topicLength];
+    if (!HASerializer::generateDataTopic(
+        fullTopic,
+        uniqueId,
+        topic
+    )) {
+        return;
+    }
+
+    HAMqtt::instance()->subscribe(fullTopic);
+}
+
+void HABaseDeviceType::onMqttMessage(
+    const char* topic,
+    const uint8_t* payload,
+    const uint16_t length
+)
+{
+    (void)topic;
+    (void)payload;
+    (void)length;
+}
+
+void HABaseDeviceType::destroySerializer()
+{
+    if (_serializer) {
+        delete _serializer;
+        _serializer = nullptr;
+    }
+}
+
+bool HABaseDeviceType::publishConfig()
+{
+    HAMqtt* mqttInstance = mqtt();
+    if (!mqttInstance) {
+        return false;
+    }
+
+    buildSerializer();
+    if (_serializer == nullptr) {
+        return false;
+    }
+
+    const uint16_t topicLength = HASerializer::calculateConfigTopicLength(
+        componentName(),
+        uniqueId()
+    );
+    const uint16_t dataLength = _serializer->calculateSize();
+
+    bool published = false;
+    if (topicLength > 0 && dataLength > 0) {
+        char topic[topicLength];
+        if (!HASerializer::generateConfigTopic(
+            topic,
+            componentName(),
+            uniqueId()
+        )) {
+            destroySerializer();
+            return false;
+        }
+
+        if (mqttInstance->beginPublish(topic, dataLength, true)) {
+            const bool flushed = _serializer->flush();
+            const bool ended = mqttInstance->endPublish();
+            published = flushed && ended;
+        }
+    }
+
+    destroySerializer();
+    return published;
+}
+
+void HABaseDeviceType::publishAvailability()
+{
+    HAMqtt* mqttInstance = mqtt();
+    if (!mqttInstance) {
+        return;
+    }
+
+    const HADevice* device = mqttInstance->getDevice();
+    if (
+        !device ||
+        device->isSharedAvailabilityEnabled() ||
+        !isAvailabilityConfigured()
+    ) {
+        return;
+    }
+
+    const bool online = (_availability == AvailabilityOnline);
+
+    if (_availabilityList.count() > 0) {
+        char defaultBuf[12];
+        const __FlashStringHelper* flashPayload = online
+            ? AHATOFSTR(HAOnline)
+            : AHATOFSTR(HAOffline);
+
+        for (uint8_t i = 0; i < _availabilityList.count(); i++) {
+            const HAAvailabilityConfig::Entry& e = _availabilityList.getEntry(i);
+            const char* payload = nullptr;
+
+            if (online) {
+                if (e.payloadAvailable && e.payloadAvailable[0] != '\0') {
+                    payload = e.payloadAvailable;
+                } else if (_payloadAvailable && _payloadAvailable[0] != '\0') {
+                    payload = _payloadAvailable;
+                } else {
+                    strncpy_P(
+                        defaultBuf,
+                        reinterpret_cast<PGM_P>(AHAFROMFSTR(flashPayload)),
+                        sizeof(defaultBuf) - 1
+                    );
+                    defaultBuf[sizeof(defaultBuf) - 1] = 0;
+                    payload = defaultBuf;
+                }
+            } else {
+                if (e.payloadNotAvailable && e.payloadNotAvailable[0] != '\0') {
+                    payload = e.payloadNotAvailable;
+                } else if (_payloadNotAvailable && _payloadNotAvailable[0] != '\0') {
+                    payload = _payloadNotAvailable;
+                } else {
+                    strncpy_P(
+                        defaultBuf,
+                        reinterpret_cast<PGM_P>(AHAFROMFSTR(flashPayload)),
+                        sizeof(defaultBuf) - 1
+                    );
+                    defaultBuf[sizeof(defaultBuf) - 1] = 0;
+                    payload = defaultBuf;
+                }
+            }
+
+            publishAbsolute(e.topic, payload, true);
+        }
+
+        return;
+    }
+
+    const char* ramPayload = online
+        ? effectivePayloadAvailable()
+        : effectivePayloadNotAvailable();
+
+    if (ramPayload) {
+        publishOnDataTopic(AHATOFSTR(HAAvailabilityTopic), ramPayload, true);
+    } else {
+        publishOnDataTopic(
+            AHATOFSTR(HAAvailabilityTopic),
+            online ? AHATOFSTR(HAOnline) : AHATOFSTR(HAOffline),
+            true
+        );
+    }
+}
+
+bool HABaseDeviceType::publishAbsolute(
+    const char* fullTopic,
+    const char* payload,
+    bool retained
+)
+{
+    if (!fullTopic || !payload || !mqtt()) {
+        return false;
+    }
+
+    HAMqtt* mqttInstance = mqtt();
+    const uint16_t len = strlen(payload);
+    if (!mqttInstance->beginPublish(fullTopic, len, retained)) {
+        return false;
+    }
+
+    const bool written = mqttInstance->writePayload(payload, len);
+    const bool ended = mqttInstance->endPublish();
+    return written && ended;
+}
+
+bool HABaseDeviceType::publishOnDataTopic(
+    const __FlashStringHelper* topic,
+    const __FlashStringHelper* payload,
+    bool retained
+)
+{
+    if (!payload) {
+        return false;
+    }
+
+    return publishOnDataTopic(
+        topic,
+        reinterpret_cast<const uint8_t*>(payload),
+        strlen_P(AHAFROMFSTR(payload)),
+        retained,
+        true
+    );
+}
+
+bool HABaseDeviceType::publishOnDataTopic(
+    const __FlashStringHelper* topic,
+    const char* payload,
+    bool retained
+)
+{
+    if (!payload) {
+        return false;
+    }
+
+    return publishOnDataTopic(
+        topic,
+        reinterpret_cast<const uint8_t*>(payload),
+        strlen(payload),
+        retained
+    );
+}
+
+bool HABaseDeviceType::publishOnDataTopic(
+    const __FlashStringHelper* topic,
+    const uint8_t* payload,
+    const uint16_t length,
+    bool retained,
+    bool isProgmemData
+)
+{
+    HAMqtt* mqttInstance = mqtt();
+    if (!payload || !mqttInstance) {
+        return false;
+    }
+
+    if (!topic) {
+        return false;
+    }
+
+    const uint16_t topicLength = HASerializer::calculateDataTopicLength(
+        uniqueId(),
+        topic
+    );
+    if (topicLength == 0) {
+        return false;
+    }
+
+    char fullTopic[topicLength];
+    if (!HASerializer::generateDataTopic(
+        fullTopic,
+        uniqueId(),
+        topic
+    )) {
+        return false;
+    }
+
+    if (mqttInstance->beginPublish(fullTopic, length, retained)) {
+        bool written = false;
+        if (isProgmemData) {
+            written = mqttInstance->writePayload(AHATOFSTR(payload));
+        } else {
+            written = mqttInstance->writePayload(payload, length);
+        }
+
+        const bool ended = mqttInstance->endPublish();
+        return written && ended;
+    }
+
+    return false;
+}
+
+bool HABaseDeviceType::shouldPublishSingleComponentConfig() const
+{
+    return !mqtt() || !mqtt()->isDeviceDiscoveryEnabled() || !supportsDeviceDiscovery();
+}
+
+void HABaseDeviceType::setEntityIdProperty(HASerializer* serializer) const
+{
+    if (!serializer) {
+        return;
+    }
+
+    const char* defaultEntityId = nonEmptyString(_defaultEntityId);
+    if (defaultEntityId) {
+        serializer->set(AHATOFSTR(HADefaultEntityIdProperty), defaultEntityId);
+    }
+}
+
+const char* HABaseDeviceType::nonEmptyString(const char* value)
+{
+    return (value && value[0] != '\0') ? value : nullptr;
+}
+
+HASerializer* HABaseDeviceType::buildDeviceDiscoverySerializer()
+{
+    return nullptr;
+}
+
+bool HABaseDeviceType::supportsDeviceDiscovery() const
+{
+    return false;
+}
+
+void HABaseDeviceType::setEnabledByDefault(bool enabled)
+{
+    _enabledByDefault = enabled;
+    _hasEnabledByDefault = true;
+}
+
+void HABaseDeviceType::clearEnabledByDefault()
+{
+    _hasEnabledByDefault = false;
+}
+
+void HABaseDeviceType::setEntityPicture(const char* url)
+{
+    _entityPicture = url;
+}
+
+void HABaseDeviceType::clearEntityPicture()
+{
+    _entityPicture = nullptr;
+}
+
+void HABaseDeviceType::setQos(uint8_t qos)
+{
+    if (qos > 2) {
+        qos = 2;
+    }
+
+    _qosNumeric = HANumeric(static_cast<uint8_t>(qos), 0);
+    _hasQos = true;
+}
+
+void HABaseDeviceType::clearQos()
+{
+    _hasQos = false;
+    _qosNumeric.reset();
+}
+
+void HABaseDeviceType::setEncoding(const char* encoding)
+{
+    _encoding = encoding;
+}
+
+void HABaseDeviceType::clearEncoding()
+{
+    _encoding = nullptr;
+}
+
+void HABaseDeviceType::setPayloadAvailable(const char* payload)
+{
+    _payloadAvailable = payload;
+}
+
+void HABaseDeviceType::setPayloadNotAvailable(const char* payload)
+{
+    _payloadNotAvailable = payload;
+}
+
+void HABaseDeviceType::setAvailabilityMode(const char* mode)
+{
+    _availabilityMode = mode;
+}
+
+bool HABaseDeviceType::addAvailabilityEntry(
+    const char* topic,
+    const char* valueTemplate,
+    const char* payloadAvailable,
+    const char* payloadNotAvailable
+)
+{
+    return _availabilityList.add(
+        topic,
+        valueTemplate,
+        payloadAvailable,
+        payloadNotAvailable
+    );
+}
+
+void HABaseDeviceType::clearAvailabilityEntries()
+{
+    _availabilityList.clear();
+}
+
+void HABaseDeviceType::applyCommonEntityProperties(
+    HASerializer* serializer,
+    bool includeEncoding
+) const
+{
+    if (!serializer) {
+        return;
+    }
+
+    if (_hasEnabledByDefault) {
+        serializer->set(
+            AHATOFSTR(HAEnabledByDefaultProperty),
+            &_enabledByDefault,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (nonEmptyString(_entityPicture)) {
+        serializer->set(AHATOFSTR(HAEntityPictureProperty), _entityPicture);
+    }
+
+    if (_hasQos) {
+        serializer->set(
+            AHATOFSTR(HAQosProperty),
+            &_qosNumeric,
+            HASerializer::NumberPropertyType
+        );
+    }
+
+    if (includeEncoding && nonEmptyString(_encoding)) {
+        serializer->set(AHATOFSTR(HAEncodingProperty), _encoding);
+    }
+}
+
+const char* HABaseDeviceType::effectivePayloadAvailable() const
+{
+    if (_payloadAvailable && _payloadAvailable[0] != '\0') {
+        return _payloadAvailable;
+    }
+
+    HAMqtt* m = mqtt();
+    if (!m) {
+        return nullptr;
+    }
+
+    const HADevice* d = m->getDevice();
+    if (d && d->isSharedAvailabilityEnabled()) {
+        return d->getPayloadAvailable();
+    }
+
+    return nullptr;
+}
+
+const char* HABaseDeviceType::effectivePayloadNotAvailable() const
+{
+    if (_payloadNotAvailable && _payloadNotAvailable[0] != '\0') {
+        return _payloadNotAvailable;
+    }
+
+    HAMqtt* m = mqtt();
+    if (!m) {
+        return nullptr;
+    }
+
+    const HADevice* d = m->getDevice();
+    if (d && d->isSharedAvailabilityEnabled()) {
+        return d->getPayloadNotAvailable();
+    }
+
+    return nullptr;
+}
+
+void HABaseDeviceType::configureAvailabilityEntries(HASerializer* serializer) const
+{
+    if (!serializer || !mqtt()) {
+        return;
+    }
+
+    const HADevice* device = mqtt()->getDevice();
+    if (!device) {
+        return;
+    }
+
+    const bool isSharedAvailability = device->isSharedAvailabilityEnabled();
+    const bool availabilityActive = isAvailabilityConfigured();
+
+    if (!isSharedAvailability && !availabilityActive) {
+        return;
+    }
+
+    const char* pa = effectivePayloadAvailable();
+    if (nonEmptyString(pa)) {
+        serializer->set(
+            AHATOFSTR(HAPayloadAvailableProperty),
+            pa,
+            HASerializer::ConstCharPropertyValue
+        );
+    }
+
+    const char* pn = effectivePayloadNotAvailable();
+    if (nonEmptyString(pn)) {
+        serializer->set(
+            AHATOFSTR(HAPayloadNotAvailableProperty),
+            pn,
+            HASerializer::ConstCharPropertyValue
+        );
+    }
+
+    if (nonEmptyString(_availabilityMode)) {
+        serializer->set(
+            AHATOFSTR(HAAvailabilityModeProperty),
+            _availabilityMode,
+            HASerializer::ConstCharPropertyValue
+        );
+    }
+
+    const bool useList =
+        !isSharedAvailability
+        && availabilityActive
+        && _availabilityList.count() > 0;
+
+    if (useList) {
+        auto* entry = serializer->addEntry();
+        if (!entry) {
+            return;
+        }
+
+        entry->type = HASerializer::AvailabilityArrayEntryType;
+        entry->subtype = 0;
+        entry->property = AHATOFSTR(HAAvailabilityListProperty);
+        entry->value = const_cast<HAAvailabilityConfig*>(&_availabilityList);
+        return;
+    }
+
+    auto* e = serializer->addEntry();
+    if (!e) {
+        return;
+    }
+
+    e->type = HASerializer::TopicEntryType;
+    e->subtype = 0;
+    e->property = AHATOFSTR(HAAvailabilityTopic);
+    e->value = isSharedAvailability
+        ? const_cast<char*>(device->getAvailabilityTopic())
+        : nullptr;
+}

src/device-types/HABaseDeviceType.h

@@ -0,0 +1,423 @@
+#ifndef AHA_HABASEDEVICETYPE_H
+#define AHA_HABASEDEVICETYPE_H
+
+#include <Arduino.h>
+#include "../ArduinoHADefines.h"
+#include "../utils/HAAvailabilityConfig.h"
+#include "../utils/HANumeric.h"
+
+class HAMqtt;
+class HASerializer;
+
+class HABaseDeviceType
+{
+public:
+    enum NumberPrecision {
+        /// No digits after the decimal point.
+        PrecisionP0 = 0,
+
+        /// One digit after the decimal point.
+        PrecisionP1,
+
+        /// Two digits after the decimal point.
+        PrecisionP2,
+
+        /// Three digits after the decimal point.
+        PrecisionP3
+    };
+
+    /**
+     * Creates a new device type instance and registers it in the HAMqtt class.
+     *
+     * @param componentName The name of the Home Assistant component (e.g. `binary_sensor`).
+     *                      You can find all available component names in the Home Assistant documentation.
+     *                      The component name needs to be stored in the flash memory.
+     * @param uniqueId The unique ID of the device type. It needs to be unique in a scope of the HADevice.
+     */
+    HABaseDeviceType(
+        const __FlashStringHelper* componentName,
+        const char* uniqueId
+    );
+
+    virtual ~HABaseDeviceType();
+    HABaseDeviceType(const HABaseDeviceType&) = delete;
+    HABaseDeviceType& operator=(const HABaseDeviceType&) = delete;
+    HABaseDeviceType(HABaseDeviceType&&) = delete;
+    HABaseDeviceType& operator=(HABaseDeviceType&&) = delete;
+
+
+    /**
+     * Returns unique ID of the device type.
+     */
+    inline const char* uniqueId() const
+        { return _uniqueId; }
+
+    /**
+     * Returns component name defined by the device type.
+     * It's used for the MQTT discovery topic.
+     */
+    inline const __FlashStringHelper* componentName() const
+        { return _componentName; }
+
+    /**
+     * Returns `true` if the availability was configured for this device type.
+     */
+    inline bool isAvailabilityConfigured() const
+        { return (_availability != AvailabilityDefault); }
+
+    /**
+     * Returns online state of the device type.
+     */
+    inline bool isOnline() const
+        { return (_availability == AvailabilityOnline); }
+
+    /**
+     * Sets name of the device type that will be used as a label in the HA panel.
+     * Keep the name short to save the resources.
+     *
+     * @param name The device type name.
+     */
+    inline void setName(const char* name)
+        { _name = name; }
+
+    /**
+     * Returns name of the deviced type that was assigned via setName method.
+     * It can be nullptr if there is no name assigned.
+     */
+    inline const char* getName() const
+        { return _name; }
+
+    /**
+     * Sets the default entity ID that Home Assistant should use when creating
+     * the entity for the first time.
+     * Keep the ID short to save the resources.
+     *
+     * @param entityId The default entity ID.
+     */
+    inline void setDefaultEntityId(const char* entityId)
+        { _defaultEntityId = entityId; }
+
+    /**
+     * Returns the default entity ID that was assigned via setDefaultEntityId.
+     * It can be nullptr if there is no ID assigned.
+     */
+    inline const char* getDefaultEntityId() const
+        { return _defaultEntityId; }
+
+    /**
+     * Legacy compatibility setter. Home Assistant no longer supports the MQTT
+     * discovery `obj_id` payload property, so this value is retained only for
+     * source compatibility and is not published.
+     *
+     * Use setDefaultEntityId("domain.entity_id") to suggest an entity ID on
+     * first discovery. It does not rename existing entities.
+     *
+     * @param objectId The object ID.
+     */
+    inline void setObjectId(const char* objectId)
+        { _objectId = objectId; }
+
+    /**
+     * Returns the object ID that was set by setObjectId method.
+     * It can be nullptr if there is no ID assigned.
+     */
+    inline const char* getObjectId() const
+        { return _objectId; }
+
+    /**
+     * Sets the entity category for this entity.
+     *
+     * @param entityCategory The category name.
+     */
+    inline void setEntityCategory(const char* entityCategory)
+        { _entityCategory = entityCategory; }
+
+    /**
+     * Returns the entity category for this entity.
+     */
+    inline const char* getEntityCategory() const
+        { return _entityCategory; }
+
+    void setEnabledByDefault(bool enabled);
+    void clearEnabledByDefault();
+
+    void setEntityPicture(const char* url);
+    void clearEntityPicture();
+
+    void setQos(uint8_t qos);
+    void clearQos();
+
+    void setEncoding(const char* encoding);
+    void clearEncoding();
+
+    void setPayloadAvailable(const char* payload);
+    void setPayloadNotAvailable(const char* payload);
+
+    void setAvailabilityMode(const char* mode);
+
+    /**
+     * Adds a full-topic availability entry for discovery (`avty` list) and publishing.
+     * Only used when this entity does not use shared device availability.
+     */
+    bool addAvailabilityEntry(
+        const char* topic,
+        const char* valueTemplate = nullptr,
+        const char* payloadAvailable = nullptr,
+        const char* payloadNotAvailable = nullptr
+    );
+
+    void clearAvailabilityEntries();
+
+    /**
+     * Sets availability of the device type.
+     * Setting the initial availability enables availability reporting for this device type.
+     * Please note that not all device types support this feature.
+     * Follow HA documentation of a specific device type to get more information.
+     *
+     * @param online Specifies whether the device type is online.
+     */
+    virtual void setAvailability(bool online);
+
+    /**
+     * Removes this entity from MQTT discovery by publishing an empty retained
+     * payload on its config topic in single-component mode. In device
+     * discovery mode, publishes Home Assistant's required component-removal
+     * marker and updates the retained device config.
+     */
+    bool removeFromDiscovery();
+
+    /**
+     * Returns true after this entity was removed from the retained device
+     * discovery payload and before it is republished.
+     */
+    inline bool isRemovedFromDeviceDiscovery() const
+        { return _deviceDiscoveryRemoved; }
+
+    /**
+     * Republishes MQTT discovery config for this entity.
+     * In device discovery mode, this also re-adds an entity previously removed
+     * from the retained device payload.
+     */
+    bool republishDiscovery();
+
+#ifdef ARDUINOHA_TEST
+    inline HASerializer* getSerializer() const
+        { return _serializer; }
+
+    inline void buildSerializerTest()
+        { buildSerializer(); }
+#endif
+
+protected:
+    /**
+     * Returns instance of the HAMqtt class.
+     */
+    static HAMqtt* mqtt();
+
+    /**
+     * Subscribes to the given data topic.
+     *
+     * @param uniqueId THe unique ID of the device type assigned via the constructor.
+     * @param topic Topic to subscribe (progmem string).
+     */
+    static void subscribeTopic(
+        const char* uniqueId,
+        const __FlashStringHelper* topic
+    );
+
+    /**
+     * Returns true if this entity should publish the single-component
+     * discovery config on connect.
+     */
+    bool shouldPublishSingleComponentConfig() const;
+
+    /**
+     * This method should build serializer that will be used for publishing the configuration.
+     * The serializer is built each time the MQTT connection is acquired.
+     * Follow implementation of the existing device types to get better understanding of the logic.
+     */
+    virtual void buildSerializer() { };
+
+    /**
+     * Writes shared MQTT discovery fields (enabled_by_default, entity_picture, qos, encoding).
+     */
+    void applyCommonEntityProperties(
+        HASerializer* serializer,
+        bool includeEncoding = true
+    ) const;
+
+    /**
+     * Populates availability-related discovery entries. Called from HASerializer::WithAvailability.
+     */
+    void configureAvailabilityEntries(HASerializer* serializer) const;
+
+    /**
+     * This method is called each time the MQTT connection is acquired.
+     * Each device type should publish its configuration and availability.
+     * It can be also used for subscribing to MQTT topics.
+     */
+    virtual void onMqttConnected() = 0;
+
+    /**
+     * This method is called each time the device receives a MQTT message.
+     * It can be any MQTT message so the method should always verify the topic.
+     *
+     * @param topic The topic on which the message was produced.
+     * @param payload The payload of the message. It can be nullptr.
+     * @param length The length of the payload.
+     */
+    virtual void onMqttMessage(
+        const char* topic,
+        const uint8_t* payload,
+        const uint16_t length
+    );
+
+    /**
+     * Destroys the existing serializer.
+     */
+    void destroySerializer();
+
+    /**
+     * Publishes configuration of this device type on the HA discovery topic.
+     */
+    bool publishConfig();
+
+    /**
+     * Publishes current availability of the device type.
+     * The message is only produced if the availability is configured for this device type.
+     */
+    void publishAvailability();
+
+    /**
+     * Publishes the given flash string on the data topic.
+     *
+     * @param topic The topic to publish on (progmem string).
+     * @param payload The message's payload (progmem string).
+     * @param retained Specifies whether the message should be retained.
+     */
+    bool publishOnDataTopic(
+        const __FlashStringHelper* topic,
+        const __FlashStringHelper* payload,
+        bool retained = false
+    );
+
+    /**
+     * Publishes the given string on the data topic.
+     *
+     * @param topic The topic to publish on (progmem string).
+     * @param payload The message's payload.
+     * @param retained Specifies whether the message should be retained.
+     */
+    bool publishOnDataTopic(
+        const __FlashStringHelper* topic,
+        const char* payload,
+        bool retained = false
+    );
+
+    /**
+     * Publishes the given data on the data topic.
+     *
+     * @param topic The topic to publish on (progmem string).
+     * @param payload The message's payload.
+     * @param length The length of the payload.
+     * @param retained Specifies whether the message should be retained.
+     * @param isProgmemData Specifies whether the given data is stored in the flash memory.
+     */
+    bool publishOnDataTopic(
+        const __FlashStringHelper* topic,
+        const uint8_t* payload,
+        const uint16_t length,
+        bool retained = false,
+        bool isProgmemData = false
+    );
+
+    /**
+     * Publishes a RAM payload on an already fully-qualified MQTT topic.
+     */
+    bool publishAbsolute(const char* fullTopic, const char* payload, bool retained = false);
+
+    /**
+     * Adds the preferred entity ID property to the serializer.
+     * Only `default_entity_id` is emitted. The legacy `obj_id` field is not
+     * supported by current Home Assistant MQTT discovery schemas.
+     */
+    void setEntityIdProperty(HASerializer* serializer) const;
+
+    /**
+     * Returns a string pointer if it is non-empty, otherwise nullptr.
+     */
+    static const char* nonEmptyString(const char* value);
+
+    /**
+     * Builds a serializer used as a device discovery component payload.
+     * Unsupported entities return nullptr.
+     */
+    virtual HASerializer* buildDeviceDiscoverySerializer();
+
+    /**
+     * Returns true when the entity can be included in MQTT device discovery.
+     */
+    virtual bool supportsDeviceDiscovery() const;
+
+    /// The component name that was assigned via the constructor.
+    const __FlashStringHelper* const _componentName;
+
+    /// The unique ID that was assigned via the constructor.
+    const char* _uniqueId;
+
+    /// The name that was set using setName method. It can be nullptr.
+    const char* _name;
+
+    /// The object ID that was set using setObjectId method. It can be nullptr.
+    const char* _objectId;
+
+    /// The default entity ID used by Home Assistant on first discovery.
+    const char* _defaultEntityId;
+
+    /// The entity category for the entity. It can be nullptr.
+    const char* _entityCategory;
+
+    /// HASerializer that belongs to this device type. It can be nullptr.
+    HASerializer* _serializer;
+
+    bool _hasEnabledByDefault;
+    bool _enabledByDefault;
+    const char* _entityPicture;
+    bool _hasQos;
+    HANumeric _qosNumeric;
+    const char* _encoding;
+    const char* _payloadAvailable;
+    const char* _payloadNotAvailable;
+    const char* _availabilityMode;
+    HAAvailabilityConfig _availabilityList;
+
+    /// Tracks an entity removed from the retained device discovery payload.
+    bool _deviceDiscoveryRemoved;
+
+    static void registerAllWith(HAMqtt& mqtt);
+
+    static HABaseDeviceType* _firstInstance;
+
+private:
+    enum Availability {
+        AvailabilityDefault = 0,
+        AvailabilityOnline,
+        AvailabilityOffline
+    };
+
+    /// The current availability of this device type. AvailabilityDefault means that the initial availability was never set.
+    Availability _availability;
+
+    const char* effectivePayloadAvailable() const;
+    /// Intrusive list entry used to register entities created before HAMqtt.
+    HABaseDeviceType* _nextInstance;
+
+    const char* effectivePayloadNotAvailable() const;
+
+    bool removeSingleComponentDiscovery();
+
+    friend class HAMqtt;
+    friend class HASerializer;
+};
+
+#endif

src/device-types/HABinarySensor.cpp

@@ -1,261 +1,224 @@
 #include "HABinarySensor.h"
-#include "../ArduinoHADefines.h"
-#include "../HAMqtt.h"
-#include "../HADevice.h"
-#include "../HAUtils.h"
+#ifndef EX_ARDUINOHA_BINARY_SENSOR
 
-HABinarySensor::HABinarySensor(
-    const char* name,
-    bool initialState,
-    HAMqtt& mqtt
-) :
-    BaseDeviceType(mqtt, "binary_sensor", name),
+#include "../HAMqtt.h"
+#include "../utils/HADictionary.h"
+#include "../utils/HASerializer.h"
+
+HABinarySensor::HABinarySensor(const char* uniqueId) :
+    HABaseDeviceType(AHATOFSTR(HAComponentBinarySensor), uniqueId),
     _class(nullptr),
-    _currentState(initialState)
+    _icon(nullptr),
+    _payloadOn(nullptr),
+    _payloadOff(nullptr),
+    _forceUpdate(false),
+    _offDelay(),
+    _valueTemplate(nullptr),
+    _currentState(false)
 {
 
 }
 
-HABinarySensor::HABinarySensor(
-    const char* name,
-    const char* deviceClass,
-    bool initialState,
-    HAMqtt& mqtt
-) :
-    BaseDeviceType(mqtt, "binary_sensor", name),
-    _class(deviceClass),
-    _currentState(initialState)
+bool HABinarySensor::setState(const bool state, const bool force)
 {
+    if (!force && state == _currentState) {
+        return true;
+    }
 
+    const bool published = publishState(state);
+    _currentState = state;
+    return published;
+}
+
+void HABinarySensor::setExpireAfter(uint16_t expireAfter)
+{
+    if (expireAfter > 0) {
+        _expireAfter.setBaseValue(expireAfter);
+    } else {
+        _expireAfter.reset();
+    }
+}
+
+void HABinarySensor::setOffDelay(uint16_t seconds)
+{
+    if (seconds > 0) {
+        _offDelay.setBaseValue(seconds);
+    } else {
+        _offDelay.reset();
+    }
+}
+
+void HABinarySensor::clearOffDelay()
+{
+    _offDelay.reset();
+}
+
+void HABinarySensor::setValueTemplate(const char* valueTemplate)
+{
+    _valueTemplate = valueTemplate;
+}
+
+void HABinarySensor::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 20);
+    _serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(_serializer);
+    _serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(_serializer);
+    _serializer->set(AHATOFSTR(HADeviceClassProperty), _class);
+    _serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    _serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (nonEmptyString(_payloadOn)) {
+        _serializer->set(AHATOFSTR(HAPayloadOnProperty), _payloadOn);
+    }
+
+    if (nonEmptyString(_payloadOff)) {
+        _serializer->set(AHATOFSTR(HAPayloadOffProperty), _payloadOff);
+    }
+
+    if (_forceUpdate) {
+        _serializer->set(
+            AHATOFSTR(HAForceUpdateProperty),
+            &_forceUpdate,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_offDelay.isSet()) {
+        _serializer->set(
+            AHATOFSTR(HAOffDelayProperty),
+            &_offDelay,
+            HASerializer::NumberPropertyType
+        );
+    }
+
+    if (nonEmptyString(_valueTemplate)) {
+        _serializer->set(AHATOFSTR(HAValueTemplateProperty), _valueTemplate);
+    }
+
+    if (_expireAfter.isSet()) {
+        _serializer->set(
+            AHATOFSTR(HAExpireAfterProperty),
+            &_expireAfter,
+            HASerializer::NumberPropertyType
+        );
+    }
+
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->set(HASerializer::WithAvailability);
+    _serializer->topic(AHATOFSTR(HAStateTopic));
+}
+
+HASerializer* HABinarySensor::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 20);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentBinarySensor),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(serializer);
+    serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(serializer);
+    serializer->set(AHATOFSTR(HADeviceClassProperty), _class);
+    serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (nonEmptyString(_payloadOn)) {
+        serializer->set(AHATOFSTR(HAPayloadOnProperty), _payloadOn);
+    }
+
+    if (nonEmptyString(_payloadOff)) {
+        serializer->set(AHATOFSTR(HAPayloadOffProperty), _payloadOff);
+    }
+
+    if (_forceUpdate) {
+        serializer->set(
+            AHATOFSTR(HAForceUpdateProperty),
+            &_forceUpdate,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_offDelay.isSet()) {
+        serializer->set(
+            AHATOFSTR(HAOffDelayProperty),
+            &_offDelay,
+            HASerializer::NumberPropertyType
+        );
+    }
+
+    if (nonEmptyString(_valueTemplate)) {
+        serializer->set(AHATOFSTR(HAValueTemplateProperty), _valueTemplate);
+    }
+
+    if (_expireAfter.isSet()) {
+        serializer->set(
+            AHATOFSTR(HAExpireAfterProperty),
+            &_expireAfter,
+            HASerializer::NumberPropertyType
+        );
+    }
+
+    serializer->set(HASerializer::WithAvailability);
+    serializer->topic(AHATOFSTR(HAStateTopic));
+    return serializer;
 }
 
 void HABinarySensor::onMqttConnected()
 {
-    if (strlen(name()) == 0) {
+    if (!uniqueId()) {
         return;
     }
 
-    publishConfig();
-    publishState(_currentState);
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
     publishAvailability();
+    publishState(_currentState);
 }
 
-bool HABinarySensor::setState(bool state)
+bool HABinarySensor::publishState(const bool state)
 {
-    if (state == _currentState) {
-        return true;
+    if (state) {
+        if (nonEmptyString(_payloadOn)) {
+            return publishOnDataTopic(
+                AHATOFSTR(HAStateTopic),
+                _payloadOn,
+                true
+            );
+        }
+
+        return publishOnDataTopic(
+            AHATOFSTR(HAStateTopic),
+            AHATOFSTR(HAStateOn),
+            true
+        );
     }
 
-    if (strlen(name()) == 0) {
-        return false;
+    if (nonEmptyString(_payloadOff)) {
+        return publishOnDataTopic(
+            AHATOFSTR(HAStateTopic),
+            _payloadOff,
+            true
+        );
     }
 
-    if (publishState(state)) {
-        _currentState = state;
-        return true;
-    }
-
-    return false;
-}
-
-void HABinarySensor::publishConfig()
-{
-    const HADevice* device = mqtt()->getDevice();
-    if (device == nullptr) {
-        return;
-    }
-
-    const uint16_t& deviceLength = device->calculateSerializedLength();
-    if (deviceLength == 0) {
-        return;
-    }
-
-    char serializedDevice[deviceLength];
-    if (device->serialize(serializedDevice) == 0) {
-        return;
-    }
-
-    const uint16_t& topicLength = DeviceTypeSerializer::calculateTopicLength(
-        mqtt(),
-        componentName(),
-        name(),
-        DeviceTypeSerializer::ConfigTopic
-    );
-    const uint16_t& dataLength = calculateSerializedLength(serializedDevice);
-
-    if (topicLength == 0 || dataLength == 0) {
-        return;
-    }
-
-    char topic[topicLength];
-    DeviceTypeSerializer::generateTopic(
-        mqtt(),
-        topic,
-        componentName(),
-        name(),
-        DeviceTypeSerializer::ConfigTopic
-    );
-
-    if (strlen(topic) == 0) {
-        return;
-    }
-
-    if (mqtt()->beginPublish(topic, dataLength, true)) {
-        writeSerializedData(serializedDevice);
-        mqtt()->endPublish();
-    }
-}
-
-bool HABinarySensor::publishState(bool state)
-{
-    if (strlen(name()) == 0) {
-        return false;
-    }
-
-    const uint16_t& topicSize = DeviceTypeSerializer::calculateTopicLength(
-        mqtt(),
-        componentName(),
-        name(),
-        DeviceTypeSerializer::StateTopic
-    );
-    if (topicSize == 0) {
-        return false;
-    }
-
-    char topic[topicSize];
-    DeviceTypeSerializer::generateTopic(
-        mqtt(),
-        topic,
-        componentName(),
-        name(),
-        DeviceTypeSerializer::StateTopic
-    );
-
-    if (strlen(topic) == 0) {
-        return false;
-    }
-
-    return mqtt()->publish(
-        topic,
-        (
-            state ?
-            DeviceTypeSerializer::StateOn :
-            DeviceTypeSerializer::StateOff
-        ),
+    return publishOnDataTopic(
+        AHATOFSTR(HAStateTopic),
+        AHATOFSTR(HAStateOff),
         true
     );
 }
 
-uint16_t HABinarySensor::calculateSerializedLength(
-    const char* serializedDevice
-) const
-{
-    if (serializedDevice == nullptr) {
-        return 0;
-    }
-
-    const HADevice* device = mqtt()->getDevice();
-    if (device == nullptr) {
-        return 0;
-    }
-
-    uint16_t size = 0;
-    size += DeviceTypeSerializer::calculateBaseJsonDataSize();
-    size += DeviceTypeSerializer::calculateNameFieldSize(name());
-    size += DeviceTypeSerializer::calculateUniqueIdFieldSize(device, name());
-    size += DeviceTypeSerializer::calculateDeviceFieldSize(serializedDevice);
-
-    if (isAvailabilityConfigured()) {
-        size += DeviceTypeSerializer::calculateAvailabilityFieldSize(
-            mqtt(),
-            componentName(),
-            name()
-        );
-    }
-
-    // state topic
-    {
-        const uint16_t& topicLength = DeviceTypeSerializer::calculateTopicLength(
-            mqtt(),
-            componentName(),
-            name(),
-            DeviceTypeSerializer::StateTopic,
-            false
-        );
-
-        if (topicLength == 0) {
-            return 0;
-        }
-
-        // Field format: "stat_t":"[TOPIC]"
-        size += topicLength + 11; // 11 - length of the JSON decorators for this field
-    }
-
-    // device class
-    if (_class != nullptr) {
-        // Field format: ,"dev_cla":"[CLASS]"
-        size += strlen(_class) + 13; // 13 - length of the JSON decorators for this field
-    }
-
-    return size; // exludes null terminator
-}
-
-bool HABinarySensor::writeSerializedData(const char* serializedDevice) const
-{
-    if (serializedDevice == nullptr) {
-        return false;
-    }
-
-    DeviceTypeSerializer::mqttWriteBeginningJson(mqtt());
-
-    // state topic
-    {
-        const uint16_t& topicSize = DeviceTypeSerializer::calculateTopicLength(
-            mqtt(),
-            componentName(),
-            name(),
-            DeviceTypeSerializer::StateTopic
-        );
-        if (topicSize == 0) {
-            return false;
-        }
-
-        char topic[topicSize];
-        DeviceTypeSerializer::generateTopic(
-            mqtt(),
-            topic,
-            componentName(),
-            name(),
-            DeviceTypeSerializer::StateTopic
-        );
-
-        if (strlen(topic) == 0) {
-            return false;
-        }
-
-        static const char Prefix[] PROGMEM = {"\"stat_t\":\""};
-        DeviceTypeSerializer::mqttWriteConstCharField(mqtt(), Prefix, topic);
-    }
-
-    // device class
-    if (_class != nullptr) {
-        static const char Prefix[] PROGMEM = {",\"dev_cla\":\""};
-        DeviceTypeSerializer::mqttWriteConstCharField(mqtt(), Prefix, _class);
-    }
-
-    DeviceTypeSerializer::mqttWriteNameField(mqtt(), name());
-    DeviceTypeSerializer::mqttWriteUniqueIdField(mqtt(), name());
-
-    if (isAvailabilityConfigured()) {
-        DeviceTypeSerializer::mqttWriteAvailabilityField(
-            mqtt(),
-            componentName(),
-            name()
-        );
-    }
-
-    DeviceTypeSerializer::mqttWriteDeviceField(mqtt(), serializedDevice);
-    DeviceTypeSerializer::mqttWriteEndJson(mqtt());
-
-    return true;
-}
+#endif

src/device-types/HABinarySensor.h

@@ -1,70 +1,126 @@
 #ifndef AHA_HABINARYSENSOR_H
 #define AHA_HABINARYSENSOR_H
 
-#include "BaseDeviceType.h"
+#include "HABaseDeviceType.h"
+#include "../utils/HANumeric.h"
 
-class HABinarySensor : public BaseDeviceType
+#ifndef EX_ARDUINOHA_BINARY_SENSOR
+
+/**
+ * HABinarySensor represents a binary sensor that allows publishing on/off state to the Home Assistant panel.
+ *
+ * @note
+ * You can find more information about this entity in the Home Assistant documentation:
+ * https://www.home-assistant.io/integrations/binary_sensor.mqtt/
+ */
+class HABinarySensor : public HABaseDeviceType
 {
 public:
     /**
-     * Initializes binary sensor.
+     * @param uniqueId The unique ID of the button. It needs to be unique in a scope of your device.
+     */
+    HABinarySensor(const char* uniqueId);
+
+    /**
+     * Changes state of the sensor and publish MQTT message.
+     * Please note that if a new value is the same as the previous one the MQTT message won't be published.
      *
-     * @param name Name of the sensor. Recommendes characters: [a-z0-9\-_]
-     * @param initialState Initial state of the sensor.
-                           It will be published right after "config" message in order to update HA state.
+     * @param state New state of the sensor (`true` - on, `false` - off).
+     * @param force Forces to update the state without comparing it to a previous known state.
+     * @returns Returns `true` if the MQTT message has been published successfully.
      */
-    HABinarySensor(
-        const char* name,
-        bool initialState,
-        HAMqtt& mqtt
-    );
+    bool setState(const bool state, const bool force = false);
 
     /**
-     * Initializes binary sensor with the specified class.
-     * You can find list of available values here: https://www.home-assistant.io/integrations/binary_sensor/#device-class
+     * Sets the number of seconds after the sensor’s state expires, if it’s not updated.
+     * By default the sensors state never expires.
      *
-     * @param name Name of the sensor. Recommendes characters: [a-z0-9\-_]
-     * @param deviceClass Name of the class (lower case).
-     * @param initialState Initial state of the sensor.
-                           It will be published right after "config" message in order to update HA state.
+     * @param expireAfter The number of seconds.
      */
-    HABinarySensor(
-        const char* name,
-        const char* deviceClass,
-        bool initialState,
-        HAMqtt& mqtt
-    );
+    void setExpireAfter(uint16_t expireAfter);
 
     /**
-     * Publishes configuration of the sensor to the MQTT.
-     */
-    virtual void onMqttConnected() override;
-
-    /**
-     * Changes state of the sensor and publishes MQTT message.
-     * Please note that if a new value is the same as previous one,
-     * the MQTT message won't be published.
+     * Sets the current state of the sensor without publishing it to Home Assistant.
+     * This method may be useful if you want to change the state before the connection with the MQTT broker is acquired.
      *
      * @param state New state of the sensor.
-     * @returns Returns true if MQTT message has been published successfully.
      */
-    bool setState(bool state);
+    inline void setCurrentState(const bool state)
+        { _currentState = state; }
 
     /**
-     * Returns last known state of the sensor.
-     * If setState method wasn't called the initial value will be returned.
+     * Returns the last known state of the sensor.
      */
-    inline bool getState() const
+    inline bool getCurrentState() const
         { return _currentState; }
 
-private:
-    void publishConfig();
-    bool publishState(bool state);
-    uint16_t calculateSerializedLength(const char* serializedDevice) const;
-    bool writeSerializedData(const char* serializedDevice) const;
+    /**
+     * Sets class of the device.
+     * You can find list of available values here: https://www.home-assistant.io/integrations/binary_sensor/#device-class
+     *
+     * @param deviceClass The class name.
+     */
+    inline void setDeviceClass(const char* deviceClass)
+        { _class = deviceClass; }
 
+    /**
+     * Sets icon of the sensor.
+     * Any icon from MaterialDesignIcons.com (for example: `mdi:home`).
+     *
+     * @param icon The icon name.
+     */
+    inline void setIcon(const char* icon)
+        { _icon = icon; }
+
+    inline void setPayloadOn(const char* payload)
+        { _payloadOn = payload; }
+
+    inline void setPayloadOff(const char* payload)
+        { _payloadOff = payload; }
+
+    inline void setForceUpdate(bool forceUpdate)
+        { _forceUpdate = forceUpdate; }
+
+    void setOffDelay(uint16_t seconds);
+    void clearOffDelay();
+
+    void setValueTemplate(const char* valueTemplate);
+
+protected:
+    virtual void buildSerializer() override;
+    virtual HASerializer* buildDeviceDiscoverySerializer() override;
+    virtual bool supportsDeviceDiscovery() const override
+        { return true; }
+    virtual void onMqttConnected() override;
+
+private:
+    /**
+     * Publishes the MQTT message with the given state.
+     *
+     * @param state The state to publish.
+     * @returns Returns `true` if the MQTT message has been published successfully.
+     */
+    bool publishState(bool state);
+
+    /// The device class. It can be nullptr.
     const char* _class;
+
+    /// The icon of the sensor. It can be nullptr.
+    const char* _icon;
+
+    /// It defines the number of seconds after the sensor’s state expires, if it’s not updated. By default the sensors state never expires.
+    HANumeric _expireAfter;
+
+    const char* _payloadOn;
+    const char* _payloadOff;
+    bool _forceUpdate;
+    HANumeric _offDelay;
+    const char* _valueTemplate;
+
+    /// Current state of the sensor. By default it's false.
     bool _currentState;
+
 };
 
 #endif
+#endif

src/device-types/HAButton.cpp

@@ -0,0 +1,164 @@
+#include "HAButton.h"
+#ifndef EX_ARDUINOHA_BUTTON
+
+#include "../HAMqtt.h"
+#include "../utils/HADictionary.h"
+#include "../utils/HASerializer.h"
+#include <string.h>
+
+HAButton::HAButton(const char* uniqueId) :
+    HABaseDeviceType(AHATOFSTR(HAComponentButton), uniqueId),
+    _class(nullptr),
+    _icon(nullptr),
+    _retain(false),
+    _payloadPress(nullptr),
+    _commandTemplate(nullptr),
+    _commandCallback(nullptr)
+{
+
+}
+
+void HAButton::setPayloadPress(const char* payload)
+{
+    _payloadPress = payload;
+}
+
+void HAButton::setCommandTemplate(const char* commandTemplate)
+{
+    _commandTemplate = commandTemplate;
+}
+
+void HAButton::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 18);
+    _serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(_serializer);
+    _serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(_serializer);
+    _serializer->set(AHATOFSTR(HADeviceClassProperty), _class);
+    _serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    _serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (nonEmptyString(_payloadPress)) {
+        _serializer->set(AHATOFSTR(HAPayloadPressProperty), _payloadPress);
+    }
+
+    if (nonEmptyString(_commandTemplate)) {
+        _serializer->set(AHATOFSTR(HACommandTemplateProperty), _commandTemplate);
+    }
+
+    // optional property
+    if (_retain) {
+        _serializer->set(
+            AHATOFSTR(HARetainProperty),
+            &_retain,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->set(HASerializer::WithAvailability);
+    _serializer->topic(AHATOFSTR(HACommandTopic));
+}
+
+HASerializer* HAButton::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 18);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentButton),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(serializer);
+    serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(serializer);
+    serializer->set(AHATOFSTR(HADeviceClassProperty), _class);
+    serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (nonEmptyString(_payloadPress)) {
+        serializer->set(AHATOFSTR(HAPayloadPressProperty), _payloadPress);
+    }
+
+    if (nonEmptyString(_commandTemplate)) {
+        serializer->set(AHATOFSTR(HACommandTemplateProperty), _commandTemplate);
+    }
+
+    if (_retain) {
+        serializer->set(
+            AHATOFSTR(HARetainProperty),
+            &_retain,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    serializer->set(HASerializer::WithAvailability);
+    serializer->topic(AHATOFSTR(HACommandTopic));
+    return serializer;
+}
+
+void HAButton::onMqttConnected()
+{
+    if (!uniqueId()) {
+        return;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
+    publishAvailability();
+    subscribeTopic(uniqueId(), AHATOFSTR(HACommandTopic));
+}
+
+void HAButton::onMqttMessage(
+    const char* topic,
+    const uint8_t* payload,
+    const uint16_t length
+)
+{
+    (void)payload;
+    (void)length;
+
+    const bool hasCommandCallback =
+        _commandCallback
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        || static_cast<bool>(_commandStdCallback)
+#endif
+    ;
+
+    if (hasCommandCallback && HASerializer::compareDataTopics(
+        topic,
+        uniqueId(),
+        AHATOFSTR(HACommandTopic)
+    )) {
+        if (
+            nonEmptyString(_payloadPress)
+            && (
+                length != strlen(_payloadPress)
+                || memcmp(payload, _payloadPress, length) != 0
+            )
+        ) {
+            return;
+        }
+
+        if (_commandCallback) {
+            _commandCallback(this);
+        }
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        if (_commandStdCallback) {
+            _commandStdCallback(this);
+        }
+#endif
+    }
+}
+
+#endif

src/device-types/HAButton.h

@@ -0,0 +1,123 @@
+#ifndef AHA_HABUTTON_H
+#define AHA_HABUTTON_H
+
+#include "HABaseDeviceType.h"
+
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+#include <functional>
+#endif
+
+#ifndef EX_ARDUINOHA_BUTTON
+
+#define HABUTTON_CALLBACK(name) void (*name)(HAButton* sender)
+
+/**
+ * HAButton represents a button that's displayed in the Home Assistant panel and
+ * triggers some logic on your Arduino/ESP device once clicked.
+ *
+ * @note
+ * You can find more information about this entity in the Home Assistant documentation:
+ * https://www.home-assistant.io/integrations/button.mqtt/
+ */
+class HAButton : public HABaseDeviceType
+{
+public:
+    /**
+     * @param uniqueId The unique ID of the button. It needs to be unique in a scope of your device.
+     */
+    HAButton(const char* uniqueId);
+
+    /**
+     * Sets class of the device.
+     * You can find list of available values here: https://www.home-assistant.io/integrations/button/#device-class
+     *
+     * @param deviceClass The class name.
+     */
+    inline void setDeviceClass(const char* deviceClass)
+        { _class = deviceClass; }
+
+    /**
+     * Sets icon of the button.
+     * Any icon from MaterialDesignIcons.com (for example: `mdi:home`).
+     *
+     * @param icon The icon name.
+     */
+    inline void setIcon(const char* icon)
+        { _icon = icon; }
+
+    /**
+     * Sets retain flag for the button's command.
+     * If set to `true` the command produced by Home Assistant will be retained.
+     *
+     * @param retain
+     */
+    inline void setRetain(const bool retain)
+        { _retain = retain; }
+
+    void setPayloadPress(const char* payload);
+    void setCommandTemplate(const char* commandTemplate);
+
+    /**
+     * Registers callback that will be called each time the press command from HA is received.
+     * Please note that it's not possible to register multiple callbacks for the same button.
+     *
+     * @param callback
+     */
+    inline void onCommand(HABUTTON_CALLBACK(callback))
+    {
+        _commandCallback = callback;
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        _commandStdCallback = nullptr;
+#endif
+    }
+
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    /**
+     * Registers callback using std::function.
+     * It allows passing capturing lambdas and std::bind expressions.
+     *
+     * @param callback
+     */
+    inline void onCommand(const std::function<void(HAButton*)>& callback)
+    {
+        _commandCallback = nullptr;
+        _commandStdCallback = callback;
+    }
+#endif
+
+protected:
+    virtual void buildSerializer() override;
+    virtual HASerializer* buildDeviceDiscoverySerializer() override;
+    virtual bool supportsDeviceDiscovery() const override
+        { return true; }
+    virtual void onMqttConnected() override;
+    virtual void onMqttMessage(
+        const char* topic,
+        const uint8_t* payload,
+        const uint16_t length
+    ) override;
+
+private:
+    /// The device class. It can be nullptr.
+    const char* _class;
+
+    /// The icon of the button. It can be nullptr.
+    const char* _icon;
+
+    /// The retain flag for the HA commands.
+    bool _retain;
+
+    const char* _payloadPress;
+    const char* _commandTemplate;
+
+    /// The command callback that will be called once clicking the button in HA panel.
+    HABUTTON_CALLBACK(_commandCallback);
+
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    /// The std::function command callback.
+    std::function<void(HAButton*)> _commandStdCallback;
+#endif
+};
+
+#endif
+#endif

src/device-types/HACamera.cpp

@@ -0,0 +1,98 @@
+#include "HACamera.h"
+#ifndef EX_ARDUINOHA_CAMERA
+
+#include "../HAMqtt.h"
+#include "../utils/HASerializer.h"
+
+HACamera::HACamera(const char* uniqueId) :
+    HABaseDeviceType(AHATOFSTR(HAComponentCamera), uniqueId),
+    _encoding(EncodingBinary),
+    _icon(nullptr)
+{
+
+}
+
+bool HACamera::publishImage(const uint8_t* data, const uint16_t length)
+{
+    if (!data) {
+        return false;
+    }
+
+    return publishOnDataTopic(AHATOFSTR(HATopic), data, length, true);
+}
+
+void HACamera::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 18);
+    _serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(_serializer);
+    _serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(_serializer, false);
+    _serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    _serializer->set(AHATOFSTR(HAIconProperty), _icon);
+    _serializer->set(
+        AHATOFSTR(HAEncodingProperty),
+        getEncodingProperty(),
+        HASerializer::ProgmemPropertyValue
+    );
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->set(HASerializer::WithAvailability);
+    _serializer->topic(AHATOFSTR(HATopic));
+}
+
+HASerializer* HACamera::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 18);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentCamera),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(serializer);
+    serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(serializer, false);
+    serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    serializer->set(AHATOFSTR(HAIconProperty), _icon);
+    serializer->set(
+        AHATOFSTR(HAEncodingProperty),
+        getEncodingProperty(),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(HASerializer::WithAvailability);
+    serializer->topic(AHATOFSTR(HATopic));
+    return serializer;
+}
+
+void HACamera::onMqttConnected()
+{
+    if (!uniqueId()) {
+        return;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
+    publishAvailability();
+}
+
+const __FlashStringHelper* HACamera::getEncodingProperty() const
+{
+    switch (_encoding) {
+    case EncodingBase64:
+        return AHATOFSTR(HAEncodingBase64);
+
+    default:
+        return nullptr;
+    }
+}
+
+#endif

src/device-types/HACamera.h

@@ -0,0 +1,80 @@
+#ifndef AHA_HACAMERA_H
+#define AHA_HACAMERA_H
+
+#include "HABaseDeviceType.h"
+
+#ifndef EX_ARDUINOHA_CAMERA
+
+/**
+ * HACamera allows to display an image in the Home Assistant panel.
+ * It can be used for publishing an image from the ESP32-Cam module or any other
+ * module that's equipped with a camera. 
+ *
+ * @note
+ * You can find more information about this entity in the Home Assistant documentation:
+ * https://www.home-assistant.io/integrations/camera.mqtt/
+ */
+class HACamera : public HABaseDeviceType
+{
+public:
+    enum ImageEncoding {
+        EncodingBinary = 1,
+        EncodingBase64
+    };
+
+    /**
+     * @param uniqueId The unique ID of the camera. It needs to be unique in a scope of your device.
+     */
+    HACamera(const char* uniqueId);
+
+    /**
+     * Publishes MQTT message with the given image data as a message content.
+     * It updates image displayed in the Home Assistant panel.
+     *
+     * @param data Image data (raw binary data or base64)
+     * @param length The length of the data.
+     * @returns Returns `true` if MQTT message has been published successfully.
+     */
+    bool publishImage(const uint8_t* data, const uint16_t length);
+
+    /**
+     * Sets encoding of the image content.
+     * Bu default Home Assistant expects raw binary data (e.g. JPEG binary data).
+     *
+     * @param encoding The image's data encoding.
+     */
+    inline void setEncoding(const ImageEncoding encoding)
+        { _encoding = encoding; }
+
+    /**
+     * Sets icon of the camera.
+     * Any icon from MaterialDesignIcons.com (for example: `mdi:home`).
+     *
+     * @param icon The icon name.
+     */
+    inline void setIcon(const char* icon)
+        { _icon = icon; }
+
+protected:
+    virtual void buildSerializer() override;
+    virtual HASerializer* buildDeviceDiscoverySerializer() override;
+    virtual bool supportsDeviceDiscovery() const override
+        { return true; }
+    virtual void onMqttConnected() override;
+
+private:
+    /**
+     * Returns progmem string representing the encoding property.
+     */
+    const __FlashStringHelper* getEncodingProperty() const;
+
+    /// The encoding of the image's data. By default it's `HACamera::EncodingBinary`.
+    ImageEncoding _encoding;
+
+    /// The icon of the camera. It can be nullptr.
+    const char* _icon;
+    
+};
+
+#endif
+#endif

src/device-types/HACover.cpp

@@ -0,0 +1,265 @@
+#include "HACover.h"
+#ifndef EX_ARDUINOHA_COVER
+
+#include "../HAMqtt.h"
+#include "../utils/HAUtils.h"
+#include "../utils/HANumeric.h"
+#include "../utils/HASerializer.h"
+
+HACover::HACover(const char* uniqueId, const Features features) :
+    HABaseDeviceType(AHATOFSTR(HAComponentCover), uniqueId),
+    _features(features),
+    _currentState(StateUnknown),
+    _currentPosition(DefaultPosition),
+    _class(nullptr),
+    _icon(nullptr),
+    _retain(false),
+    _optimistic(false),
+    _commandCallback(nullptr)
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    , _commandStdCallback()
+#endif
+{
+
+}
+
+bool HACover::setState(const CoverState state, const bool force)
+{
+    if (!force && _currentState == state) {
+        return true;
+    }
+
+    if (state == StateUnknown) {
+        return false;
+    }
+
+    const bool published = publishState(state);
+    _currentState = state;
+    return published;
+}
+
+bool HACover::setPosition(const int16_t position, const bool force)
+{
+    if (!force && _currentPosition == position) {
+        return true;
+    }
+
+    if (position == DefaultPosition || !(_features & PositionFeature)) {
+        return false;
+    }
+
+    const bool published = publishPosition(position);
+    _currentPosition = position;
+    return published;
+}
+
+void HACover::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 22);
+    _serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(_serializer);
+    _serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(_serializer);
+    _serializer->set(AHATOFSTR(HADeviceClassProperty), _class);
+    _serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    _serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (_retain) {
+        _serializer->set(
+            AHATOFSTR(HARetainProperty),
+            &_retain,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_optimistic) {
+        _serializer->set(
+            AHATOFSTR(HAOptimisticProperty),
+            &_optimistic,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->set(HASerializer::WithAvailability);
+    _serializer->topic(AHATOFSTR(HAStateTopic));
+    _serializer->topic(AHATOFSTR(HACommandTopic));
+
+    if (_features & PositionFeature) {
+        _serializer->topic(AHATOFSTR(HAPositionTopic));
+    }
+}
+
+HASerializer* HACover::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 22);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentCover),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(serializer);
+    serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(serializer);
+    serializer->set(AHATOFSTR(HADeviceClassProperty), _class);
+    serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (_retain) {
+        serializer->set(
+            AHATOFSTR(HARetainProperty),
+            &_retain,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_optimistic) {
+        serializer->set(
+            AHATOFSTR(HAOptimisticProperty),
+            &_optimistic,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    serializer->set(HASerializer::WithAvailability);
+    serializer->topic(AHATOFSTR(HAStateTopic));
+    serializer->topic(AHATOFSTR(HACommandTopic));
+
+    if (_features & PositionFeature) {
+        serializer->topic(AHATOFSTR(HAPositionTopic));
+    }
+
+    return serializer;
+}
+
+void HACover::onMqttConnected()
+{
+    if (!uniqueId()) {
+        return;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
+    publishAvailability();
+
+    if (!_retain) {
+        publishState(_currentState);
+        publishPosition(_currentPosition);
+    }
+
+    subscribeTopic(uniqueId(), AHATOFSTR(HACommandTopic));
+}
+
+void HACover::onMqttMessage(
+    const char* topic,
+    const uint8_t* payload,
+    const uint16_t length
+)
+{
+    if (HASerializer::compareDataTopics(
+        topic,
+        uniqueId(),
+        AHATOFSTR(HACommandTopic)
+    )) {
+        handleCommand(payload, length);
+    }
+}
+
+bool HACover::publishState(CoverState state)
+{
+    if (state == StateUnknown) {
+        return false;
+    }
+
+    const __FlashStringHelper *stateStr = nullptr;
+    switch (state) {
+    case StateClosed:
+        stateStr = AHATOFSTR(HAClosedState);
+        break;
+
+    case StateClosing:
+        stateStr = AHATOFSTR(HAClosingState);
+        break;
+
+    case StateOpen:
+        stateStr = AHATOFSTR(HAOpenState);
+        break;
+
+    case StateOpening:
+        stateStr = AHATOFSTR(HAOpeningState);
+        break;
+
+    case StateStopped:
+        stateStr = AHATOFSTR(HAStoppedState);
+        break;
+
+    default:
+        return false;
+    }
+
+    return publishOnDataTopic(AHATOFSTR(HAStateTopic), stateStr, true);
+}
+
+bool HACover::publishPosition(int16_t position)
+{
+    if (position == DefaultPosition || !(_features & PositionFeature)) {
+        return false;
+    }
+
+    char str[6 + 1] = {0}; // int16_t digits with null terminator
+    HANumeric(position, 0).toStr(str);
+
+    return publishOnDataTopic(AHATOFSTR(HAPositionTopic), str, true);
+}
+
+void HACover::handleCommand(const uint8_t* cmd, const uint16_t length)
+{
+    const bool hasCommandCallback =
+        _commandCallback
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        || static_cast<bool>(_commandStdCallback)
+#endif
+    ;
+
+    if (!hasCommandCallback) {
+        return;
+    }
+
+    CoverCommand command;
+    bool handled = false;
+    if (memcmp_P(cmd, HACloseCommand, length) == 0) {
+        command = CommandClose;
+        handled = true;
+    } else if (memcmp_P(cmd, HAOpenCommand, length) == 0) {
+        command = CommandOpen;
+        handled = true;
+    } else if (memcmp_P(cmd, HAStopCommand, length) == 0) {
+        command = CommandStop;
+        handled = true;
+    }
+
+    if (!handled) {
+        return;
+    }
+
+    if (_commandCallback) {
+        _commandCallback(command, this);
+    }
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    if (_commandStdCallback) {
+        _commandStdCallback(command, this);
+    }
+#endif
+}
+
+#endif

src/device-types/HACover.h

@@ -0,0 +1,241 @@
+#ifndef AHA_HACOVER_H
+#define AHA_HACOVER_H
+
+#include "HABaseDeviceType.h"
+
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+#include <functional>
+#endif
+
+#ifndef EX_ARDUINOHA_COVER
+
+#define HACOVER_CALLBACK(name) void (*name)(CoverCommand cmd, HACover* sender)
+
+/**
+ * HACover allows to control a cover (such as blinds, a roller shutter or a garage door).
+ *
+ * @note
+ * You can find more information about this entity in the Home Assistant documentation:
+ * https://www.home-assistant.io/integrations/cover.mqtt/
+ */
+class HACover : public HABaseDeviceType
+{
+public:
+    static const int16_t DefaultPosition = -32768;
+
+    enum CoverState {
+        StateUnknown = 0,
+        StateClosed,
+        StateClosing,
+        StateOpen,
+        StateOpening,
+        StateStopped
+    };
+
+    enum CoverCommand {
+        CommandOpen,
+        CommandClose,
+        CommandStop
+    };
+
+    enum Features {
+        DefaultFeatures = 0,
+        PositionFeature = 1
+    };
+
+    /**
+     * @param uniqueId The unique ID of the cover. It needs to be unique in a scope of your device.
+     * @param features Features that should be enabled for the fan.
+     */
+    HACover(const char* uniqueId, const Features features = DefaultFeatures);
+
+    /**
+     * Changes state of the cover and publishes MQTT message.
+     * Please note that if a new value is the same as previous one,
+     * the MQTT message won't be published.
+     *
+     * @param state New state of the cover.
+     * @param force Forces to update state without comparing it to previous known state.
+     * @returns Returns true if MQTT message has been published successfully.
+     */
+    bool setState(const CoverState state, const bool force = false);
+
+    /**
+     * Changes the position of the cover and publishes MQTT message.
+     * Please note that if a new value is the same as previous one,
+     * the MQTT message won't be published.
+     *
+     * @param position The new position of the cover (0-100).
+     * @param force Forces to update the state without comparing it to a previous known state.
+     * @returns Returns `true` if MQTT message has been published successfully.
+     */
+    bool setPosition(const int16_t position, const bool force = false);
+
+    /**
+     * Sets the current state of the cover without publishing it to Home Assistant.
+     * This method may be useful if you want to change the state before the connection
+     * with the MQTT broker is acquired.
+     *
+     * @param state The new state of the cover.
+     */
+    inline void setCurrentState(const CoverState state)
+        { _currentState = state; }
+
+    /**
+     * Returns last known state of the cover.
+     * By default the state is set to CoverState::StateUnknown
+     */
+    inline CoverState getCurrentState() const
+        { return _currentState; }
+
+    /**
+     * Sets the current position of the cover without pushing the value to Home Assistant.
+     * This method may be useful if you want to change the position before the connection
+     * with the MQTT broker is acquired.
+     *
+     * @param position The new position of the cover (0-100).
+     */
+    inline void setCurrentPosition(const int16_t position)
+        { _currentPosition = position; }
+
+    /**
+     * Returns the last known position of the cover.
+     * By default position is set to HACover::DefaultPosition
+     */
+    inline int16_t getCurrentPosition() const
+        { return _currentPosition; }
+
+    /**
+     * Sets class of the device.
+     * You can find list of available values here: https://www.home-assistant.io/integrations/cover/
+     *
+     * @param deviceClass The class name.
+     */
+    inline void setDeviceClass(const char* deviceClass)
+        { _class = deviceClass; }
+
+    /**
+     * Sets icon of the cover.
+     * Any icon from MaterialDesignIcons.com (for example: `mdi:home`).
+     *
+     * @param icon The icon name.
+     */
+    inline void setIcon(const char* icon)
+        { _icon = icon; }
+
+    /**
+     * Sets retain flag for the cover's command.
+     * If set to `true` the command produced by Home Assistant will be retained.
+     *
+     * @param retain
+     */
+    inline void setRetain(const bool retain)
+        { _retain = retain; }
+
+    /**
+     * Sets optimistic flag for the cover state.
+     * In this mode the cover state doesn't need to be reported back to the HA panel when a command is received.
+     * By default the optimistic mode is disabled.
+     *
+     * @param optimistic The optimistic mode (`true` - enabled, `false` - disabled).
+     */
+    inline void setOptimistic(const bool optimistic)
+        { _optimistic = optimistic; }
+
+    /**
+     * Registers callback that will be called each time the command from HA is received.
+     * Please note that it's not possible to register multiple callbacks for the same cover.
+     *
+     * @param callback
+     */
+    inline void onCommand(HACOVER_CALLBACK(callback))
+    {
+        _commandCallback = callback;
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        _commandStdCallback = nullptr;
+#endif
+    }
+
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    /**
+     * Registers callback using std::function.
+     * It allows passing capturing lambdas and std::bind expressions.
+     *
+     * @param callback
+     */
+    inline void onCommand(const std::function<void(CoverCommand, HACover*)>& callback)
+    {
+        _commandCallback = nullptr;
+        _commandStdCallback = callback;
+    }
+#endif
+
+protected:
+    virtual void buildSerializer() override;
+    virtual HASerializer* buildDeviceDiscoverySerializer() override;
+    virtual bool supportsDeviceDiscovery() const override
+        { return true; }
+    virtual void onMqttConnected() override;
+    virtual void onMqttMessage(
+        const char* topic,
+        const uint8_t* payload,
+        const uint16_t length
+    ) override;
+
+private:
+    /**
+     * Publishes the MQTT message with the given state.
+     *
+     * @param state The state to publish.
+     * @returns Returns `true` if the MQTT message has been published successfully.
+     */
+    bool publishState(const CoverState state);
+
+    /**
+     * Publishes the MQTT message with the given position.
+     *
+     * @param position The position to publish.
+     * @returns Returns `true` if the MQTT message has been published successfully.
+     */
+    bool publishPosition(const int16_t position);
+
+    /**
+     * Parses the given command and executes the cover's callback with proper enum's property.
+     *
+     * @param cmd The data of the command.
+     * @param length Length of the command.
+     */
+    void handleCommand(const uint8_t* cmd, const uint16_t length);
+
+    /// Features enabled for the cover.
+    const uint8_t _features;
+
+    /// The current state of the cover. By default it's `HACover::StateUnknown`.
+    CoverState _currentState;
+
+    /// The current position of the cover. By default it's `HACover::DefaultPosition`.
+    int16_t _currentPosition;
+
+    /// The device class. It can be nullptr.
+    const char* _class;
+
+    /// The icon of the button. It can be nullptr.
+    const char* _icon;
+
+    /// The retain flag for the HA commands.
+    bool _retain;
+
+    /// The optimistic mode of the cover (`true` - enabled, `false` - disabled).
+    bool _optimistic;
+
+    /// The command callback that will be called when clicking the cover's button in the HA panel.
+    HACOVER_CALLBACK(_commandCallback);
+
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    /// The std::function callback that will be called when clicking the cover's button in the HA panel.
+    std::function<void(CoverCommand, HACover*)> _commandStdCallback;
+#endif
+};
+
+#endif
+#endif

src/device-types/HADeviceTracker.cpp

@@ -0,0 +1,138 @@
+#include "HADeviceTracker.h"
+#ifndef EX_ARDUINOHA_DEVICE_TRACKER
+
+#include "../HAMqtt.h"
+#include "../utils/HASerializer.h"
+
+HADeviceTracker::HADeviceTracker(const char* uniqueId) :
+    HABaseDeviceType(AHATOFSTR(HAComponentDeviceTracker), uniqueId),
+    _icon(nullptr),
+    _sourceType(SourceTypeUnknown),
+    _currentState(StateUnknown)
+{
+
+}
+
+bool HADeviceTracker::setState(const TrackerState state, const bool force)
+{
+    if (!force && state == _currentState) {
+        return true;
+    }
+
+    if (state == StateUnknown) {
+        return false;
+    }
+
+    const bool published = publishState(state);
+    _currentState = state;
+    return published;
+}
+
+void HADeviceTracker::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 18);
+    _serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(_serializer);
+    _serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(_serializer);
+    _serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    _serializer->set(AHATOFSTR(HAIconProperty), _icon);
+    _serializer->set(
+        AHATOFSTR(HASourceTypeProperty),
+        getSourceTypeProperty(),
+        HASerializer::ProgmemPropertyValue
+    );
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->set(HASerializer::WithAvailability);
+    _serializer->topic(AHATOFSTR(HAStateTopic));
+}
+
+HASerializer* HADeviceTracker::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 18);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentDeviceTracker),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(serializer);
+    serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(serializer);
+    serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    serializer->set(AHATOFSTR(HAIconProperty), _icon);
+    serializer->set(
+        AHATOFSTR(HASourceTypeProperty),
+        getSourceTypeProperty(),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(HASerializer::WithAvailability);
+    serializer->topic(AHATOFSTR(HAStateTopic));
+    return serializer;
+}
+
+void HADeviceTracker::onMqttConnected()
+{
+    if (!uniqueId()) {
+        return;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
+    publishAvailability();
+    publishState(_currentState);
+}
+
+bool HADeviceTracker::publishState(const TrackerState state)
+{
+    const __FlashStringHelper *stateStr = nullptr;
+    switch (state) {
+    case StateHome:
+        stateStr = AHATOFSTR(HAHome);
+        break;
+
+    case StateNotHome:
+        stateStr = AHATOFSTR(HANotHome);
+        break;
+
+    case StateNotAvailable:
+        stateStr = AHATOFSTR(HAOffline);
+        break;
+
+    default:
+        return false;
+    }
+
+    return publishOnDataTopic(AHATOFSTR(HAStateTopic), stateStr, true);
+}
+
+const __FlashStringHelper* HADeviceTracker::getSourceTypeProperty() const
+{
+    switch (_sourceType) {
+    case SourceTypeGPS:
+        return AHATOFSTR(HAGPSType);
+
+    case SourceTypeRouter:
+        return AHATOFSTR(HARouterType);
+
+    case SourceTypeBluetooth:
+        return AHATOFSTR(HABluetoothType);
+
+    case SourceTypeBluetoothLE:
+        return AHATOFSTR(HABluetoothLEType);
+
+    default:
+        return nullptr;
+    }
+}
+
+#endif

src/device-types/HADeviceTracker.h

@@ -0,0 +1,117 @@
+#ifndef AHA_HADEVICETRACKER_H
+#define AHA_HADEVICETRACKER_H
+
+#include "HABaseDeviceType.h"
+
+#ifndef EX_ARDUINOHA_DEVICE_TRACKER
+
+/**
+ * HADeviceTracker allows to implement a custom device's tracker.
+ *
+ * @note
+ * You can find more information about this entity in the Home Assistant documentation:
+ * https://www.home-assistant.io/integrations/device_tracker.mqtt/
+ */
+class HADeviceTracker : public HABaseDeviceType
+{
+public:
+    /// Available source types of the tracker.
+    enum SourceType {
+        SourceTypeUnknown = 0,
+        SourceTypeGPS,
+        SourceTypeRouter,
+        SourceTypeBluetooth,
+        SourceTypeBluetoothLE
+    };
+
+    /// Available states that can be reported to the HA panel.
+    enum TrackerState {
+        StateUnknown = 0,
+        StateHome,
+        StateNotHome,
+        StateNotAvailable
+    };
+
+    /**
+     * @param uniqueId The unique ID of the tracker. It needs to be unique in a scope of your device.
+     */
+    HADeviceTracker(const char* uniqueId);
+
+    /**
+     * Changes the state of the tracker and publishes MQTT message.
+     * Please note that if a new value is the same as previous one,
+     * the MQTT message won't be published.
+     *
+     * @param state The new state of the tracker.
+     * @param force Forces to update the state without comparing it to a previous known state.
+     * @returns Returns `true` if MQTT message has been published successfully.
+     */
+    bool setState(const TrackerState state, const bool force = false);
+
+    /**
+     * Sets the current state of the tracker without publishing it to Home Assistant.
+     * This method may be useful if you want to change the state before connection
+     * with MQTT broker is acquired.
+     *
+     * @param state The new state of the tracker.
+     */
+    inline void setCurrentState(const TrackerState state)
+        { _currentState = state; }
+
+    /**
+     * Returns the last known state of the tracker.
+     * If setState method wasn't called the initial value will be returned.
+     */
+    inline TrackerState getState() const
+        { return _currentState; }
+
+    /**
+     * Sets icon of the tracker.
+     * Any icon from MaterialDesignIcons.com (for example: `mdi:home`).
+     *
+     * @param icon The icon name.
+     */
+    inline void setIcon(const char* icon)
+        { _icon = icon; }
+
+    /**
+     * Sets the source type of the tracker.
+     *
+     * @param type The source type (gps, router, bluetooth, bluetooth LE).
+     */
+    inline void setSourceType(const SourceType type)
+        { _sourceType = type; }
+
+protected:
+    virtual void buildSerializer() override;
+    virtual HASerializer* buildDeviceDiscoverySerializer() override;
+    virtual bool supportsDeviceDiscovery() const override
+        { return true; }
+    virtual void onMqttConnected() override;
+
+private:
+   /**
+     * Publishes the MQTT message with the given state.
+     * 
+     * @param state The state to publish.
+     * @returns Returns `true` if the MQTT message has been published successfully.
+     */
+    bool publishState(TrackerState state);
+
+    /**
+     * Returns progmem string representing source type of the tracker.
+     */
+    const __FlashStringHelper* getSourceTypeProperty() const;
+
+    /// The icon of the tracker. It can be nullptr.
+    const char* _icon;
+
+    /// The source type of the tracker. By default it's `HADeviceTracker::SourceTypeUnknown`.
+    SourceType _sourceType;
+
+    /// The current state of the device's tracker. By default its `HADeviceTracker::StateUnknown`.
+    TrackerState _currentState;
+};
+
+#endif
+#endif

src/device-types/HADeviceTrigger.cpp

@@ -0,0 +1,246 @@
+#include "HADeviceTrigger.h"
+#ifndef EX_ARDUINOHA_DEVICE_TRIGGER
+
+#include "../HAMqtt.h"
+#include "../utils/HASerializer.h"
+
+HADeviceTrigger::HADeviceTrigger(const char* type, const char* subtype) :
+    HABaseDeviceType(AHATOFSTR(HAComponentDeviceAutomation), nullptr),
+    _type(type),
+    _subtype(subtype),
+    _isProgmemType(false),
+    _isProgmemSubtype(false)
+{
+    buildUniqueId();
+}
+
+HADeviceTrigger::HADeviceTrigger(TriggerType type, const char* subtype) :
+    HABaseDeviceType(AHATOFSTR(HAComponentDeviceAutomation), nullptr),
+    _type(determineProgmemType(type)),
+    _subtype(subtype),
+    _isProgmemType(true),
+    _isProgmemSubtype(false)
+{
+    buildUniqueId();
+}
+
+HADeviceTrigger::HADeviceTrigger(const char* type, TriggerSubtype subtype) :
+    HABaseDeviceType(AHATOFSTR(HAComponentDeviceAutomation), nullptr),
+    _type(type),
+    _subtype(determineProgmemSubtype(subtype)),
+    _isProgmemType(false),
+    _isProgmemSubtype(true)
+{
+    buildUniqueId();
+}
+
+HADeviceTrigger::HADeviceTrigger(TriggerType type, TriggerSubtype subtype) :
+    HABaseDeviceType(AHATOFSTR(HAComponentDeviceAutomation), nullptr),
+    _type(determineProgmemType(type)),
+    _subtype(determineProgmemSubtype(subtype)),
+    _isProgmemType(true),
+    _isProgmemSubtype(true)
+{
+    buildUniqueId();
+}
+
+HADeviceTrigger::~HADeviceTrigger()
+{
+    if (_uniqueId) {
+        delete[] _uniqueId;
+    }
+}
+
+bool HADeviceTrigger::trigger()
+{
+    if (!_type || !_subtype) {
+        return false;
+    }
+
+    return publishOnDataTopic(AHATOFSTR(HATopic), "");
+}
+
+void HADeviceTrigger::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 5); // 5 - max properties nb
+    _serializer->set(
+        AHATOFSTR(HAAutomationTypeProperty),
+        AHATOFSTR(HATrigger),
+        HASerializer::ProgmemPropertyValue
+    );
+    _serializer->set(
+        AHATOFSTR(HATypeProperty),
+        _type,
+        _isProgmemType
+            ? HASerializer::ProgmemPropertyValue
+            : HASerializer::ConstCharPropertyValue
+    );
+    _serializer->set(
+        AHATOFSTR(HASubtypeProperty),
+        _subtype,
+        _isProgmemSubtype
+            ? HASerializer::ProgmemPropertyValue
+            : HASerializer::ConstCharPropertyValue
+    );
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->topic(AHATOFSTR(HATopic));
+}
+
+HASerializer* HADeviceTrigger::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 6);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentDeviceAutomation),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(
+        AHATOFSTR(HAAutomationTypeProperty),
+        AHATOFSTR(HATrigger),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(
+        AHATOFSTR(HATypeProperty),
+        _type,
+        _isProgmemType
+            ? HASerializer::ProgmemPropertyValue
+            : HASerializer::ConstCharPropertyValue
+    );
+    serializer->set(
+        AHATOFSTR(HASubtypeProperty),
+        _subtype,
+        _isProgmemSubtype
+            ? HASerializer::ProgmemPropertyValue
+            : HASerializer::ConstCharPropertyValue
+    );
+    serializer->topic(AHATOFSTR(HATopic));
+    return serializer;
+}
+
+void HADeviceTrigger::onMqttConnected()
+{
+    if (!uniqueId()) {
+        return;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
+}
+
+uint16_t HADeviceTrigger::calculateIdSize() const
+{
+    if (!_type || !_subtype) {
+        return 0;
+    }
+
+    const uint16_t typeSize = _isProgmemType ? strlen_P(_type) : strlen(_type);
+    const uint16_t subtypeSize = _isProgmemSubtype
+        ? strlen_P(_subtype)
+        : strlen(_subtype);
+
+    // plus underscore separator and null terminator
+    return typeSize + subtypeSize + 2;
+}
+
+void HADeviceTrigger::buildUniqueId()
+{
+    const uint16_t idSize = calculateIdSize();
+    if (idSize == 0) {
+        return;
+    }
+
+    char* id = new char[idSize];
+
+    if (_isProgmemType) {
+        strcpy_P(id, _type);
+    } else {
+        strcpy(id, _type);
+    }
+
+    strcat_P(id, HASerializerUnderscore);
+
+    if (_isProgmemSubtype) {
+        strcat_P(id, _subtype);
+    } else {
+        strcat(id, _subtype);
+    }
+
+    _uniqueId = id;
+}
+
+const char* HADeviceTrigger::determineProgmemType(TriggerType type) const
+{
+    switch (type) {
+    case ButtonShortPressType:
+        return HAButtonShortPressType;
+
+    case ButtonShortReleaseType:
+        return HAButtonShortReleaseType;
+
+    case ButtonLongPressType:
+        return HAButtonLongPressType;
+
+    case ButtonLongReleaseType:
+        return HAButtonLongReleaseType;
+
+    case ButtonDoublePressType:
+        return HAButtonDoublePressType;
+
+    case ButtonTriplePressType:
+        return HAButtonTriplePressType;
+
+    case ButtonQuadruplePressType:
+        return HAButtonQuadruplePressType;
+
+    case ButtonQuintuplePressType:
+        return HAButtonQuintuplePressType;
+
+    default:
+        return nullptr;
+    }
+}
+
+const char* HADeviceTrigger::determineProgmemSubtype(
+    TriggerSubtype subtype
+) const
+{
+    switch (subtype) {
+    case TurnOnSubtype:
+        return HATurnOnSubtype;
+
+    case TurnOffSubtype:
+        return HATurnOffSubtype;
+
+    case Button1Subtype:
+        return HAButton1Subtype;
+
+    case Button2Subtype:
+        return HAButton2Subtype;
+
+    case Button3Subtype:
+        return HAButton3Subtype;
+
+    case Button4Subtype:
+        return HAButton4Subtype;
+
+    case Button5Subtype:
+        return HAButton5Subtype;
+
+    case Button6Subtype:
+        return HAButton6Subtype;
+
+    default:
+        return nullptr;
+    }
+}
+
+#endif

src/device-types/HADeviceTrigger.h

@@ -0,0 +1,179 @@
+#ifndef AHA_HADEVICETRIGGER_H
+#define AHA_HADEVICETRIGGER_H
+
+#include "HABaseDeviceType.h"
+
+#ifndef EX_ARDUINOHA_DEVICE_TRIGGER
+
+/**
+ * HADeviceTrigger allows to a custom trigger that can be used in the Home Assistant automation.
+ * For example, it can be a wall switch that produces `press` and `long_press` actions.
+ *
+ * @note
+ * You can find more information about this entity in the Home Assistant documentation:
+ * https://www.home-assistant.io/integrations/device_trigger.mqtt/
+ */
+class HADeviceTrigger : public HABaseDeviceType
+{
+public:
+    /// Built-in types of the trigger.
+    enum TriggerType {
+        ButtonShortPressType = 1,
+        ButtonShortReleaseType,
+        ButtonLongPressType,
+        ButtonLongReleaseType,
+        ButtonDoublePressType,
+        ButtonTriplePressType,
+        ButtonQuadruplePressType,
+        ButtonQuintuplePressType
+    };
+
+    /// Built-in subtypes of the trigger.
+    enum TriggerSubtype {
+        TurnOnSubtype = 1,
+        TurnOffSubtype,
+        Button1Subtype,
+        Button2Subtype,
+        Button3Subtype,
+        Button4Subtype,
+        Button5Subtype,
+        Button6Subtype
+    };
+
+    /**
+     * Creates the device trigger with a custom type and subtype.
+     * For example, it can be `click` as the type and `btn0` as the subtype.
+     * Please note that combination of the type and subtype needs to be unique in a scope of your device.
+     *
+     * @param type String representation of the type.
+     * @param subtype String representation of the subtype.
+     */
+    HADeviceTrigger(const char* type, const char* subtype);
+
+    /**
+     * Creates the device trigger with a built-in type and a custom subtype.
+     * For example, it can be `HADeviceTrigger::ButtonShortPressType` as the type and `btn0` as the subtype.
+     * Please note that combination of the type and subtype needs to be unique in a scope of your device.
+     *
+     * @param type Built-in type of the trigger.
+     * @param subtype String representation of the subtype.
+     */
+    HADeviceTrigger(TriggerType type, const char* subtype);
+
+    /**
+     * Creates the device trigger with a custom type and a built-in subtype.
+     * For example, it can be `click` as the type and `HADeviceTrigger::Button1Subtype` as the subtype.
+     * Please note that combination of the type and subtype needs to be unique in a scope of your device.
+     *
+     * @param type String representation of the subtype.
+     * @param subtype Built-in subtype of the trigger.
+     */
+    HADeviceTrigger(const char* type, TriggerSubtype subtype);
+
+    /**
+     * Creates the device trigger with a built-in type and built-in subtype.
+     * For example, it can be `HADeviceTrigger::ButtonShortPressType` as the type and `HADeviceTrigger::Button1Subtype` as the subtype.
+     * Please note that combination of the type and subtype needs to be unique in a scope of your device.
+     *
+     * @param type Built-in type of the trigger.
+     * @param subtype Built-in subtype of the trigger.
+     */
+    HADeviceTrigger(TriggerType type, TriggerSubtype subtype);
+
+    /**
+     * Frees memory allocated by the class.
+     */
+    ~HADeviceTrigger();
+
+    /**
+     * Publishes MQTT message with the trigger event.
+     * The published message is not retained.
+     *
+     * @returns Returns `true` if MQTT message has been published successfully.
+     */
+    bool trigger();
+
+    /**
+     * Returns the type of the trigger.
+     * If the built-in type is used the returned value points to the flash memory.
+     * Use `HADeviceTrigger::isProgmemType` to verify if the returned value is the progmem pointer.
+     *
+     * @returns Pointer to the type.
+     */
+    inline const char* getType() const
+        { return _type; }
+
+    /**
+     * Returns `true` if the built-in type was assigned to the trigger.
+     */
+    inline bool isProgmemType() const
+        { return _isProgmemType; }
+
+    /**
+     * Returns the subtype of the trigger.
+     * If the built-in subtype is used the returned value points to the flash memory.
+     * Use `HADeviceTrigger::isProgmemSubtype` to verify if the returned value is the progmem pointer.
+     *
+     * @returns Pointer to the subtype.
+     */
+    inline const char* getSubtype() const
+        { return _subtype; }
+
+    /**
+     * Returns `true` if the built-in subtype was assigned to the trigger.
+     */
+    inline bool isProgmemSubtype() const
+        { return _isProgmemSubtype; }
+
+protected:
+    virtual void buildSerializer() override;
+    virtual HASerializer* buildDeviceDiscoverySerializer() override;
+    virtual bool supportsDeviceDiscovery() const override
+        { return true; }
+    virtual void onMqttConnected() override;
+
+private:
+    /**
+     * Calculates desired size of the unique ID based on the type and subtype that were passed to the constructor.
+     */
+    uint16_t calculateIdSize() const;
+
+    /**
+     * Builds the unique ID of the device's type based on the type and subtype that were passed to the constructor.
+     */
+    void buildUniqueId();
+
+    /**
+     * Returns pointer to the flash memory that represents the given type.
+     * 
+     * @param subtype Built-in type enum's value.
+     * @returns Pointer to the flash memory if the given type is supported.
+     *          For the unsupported type the nullptr is returned.
+     */
+    const char* determineProgmemType(TriggerType type) const;
+
+    /**
+     * Returns pointer to the flash memory that represents the given subtype.
+     * 
+     * @param subtype Built-in subtype enum's value.
+     * @returns Pointer to the flash memory if the given subtype is supported.
+     *          For the unsupported subtype the nullptr is returned.
+     */
+    const char* determineProgmemSubtype(TriggerSubtype subtype) const;
+
+private:
+    /// Pointer to the trigger's type. It can be pointer to the flash memory.
+    const char* _type;
+
+    /// Pointer to the trigger's subtype. It can be pointer to the flash memory.
+    const char* _subtype;
+    
+    /// Specifies whether the type points to the flash memory.
+    bool _isProgmemType;
+    
+    /// Specifies whether the subtype points to the flash memory.
+    bool _isProgmemSubtype;
+};
+
+#endif
+#endif

src/device-types/HAFan.cpp

@@ -0,0 +1,291 @@
+#include "HAFan.h"
+#ifndef EX_ARDUINOHA_FAN
+
+#include "../HAMqtt.h"
+#include "../utils/HAUtils.h"
+#include "../utils/HASerializer.h"
+
+HAFan::HAFan(const char* uniqueId, const uint8_t features) :
+    HABaseDeviceType(AHATOFSTR(HAComponentFan), uniqueId),
+    _features(features),
+    _icon(nullptr),
+    _retain(false),
+    _optimistic(false),
+    _speedRangeMax(),
+    _speedRangeMin(),
+    _currentState(false),
+    _currentSpeed(0),
+    _stateCallback(nullptr),
+    _speedCallback(nullptr)
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    , _stateStdCallback(),
+    _speedStdCallback()
+#endif
+{
+
+}
+
+bool HAFan::setState(const bool state, const bool force)
+{
+    if (!force && state == _currentState) {
+        return true;
+    }
+
+    const bool published = publishState(state);
+    _currentState = state;
+    return published;
+}
+
+bool HAFan::setSpeed(const uint16_t speed, const bool force)
+{
+    if (!force && speed == _currentSpeed) {
+        return true;
+    }
+
+    if (!(_features & SpeedsFeature)) {
+        return false;
+    }
+
+    const bool published = publishSpeed(speed);
+    _currentSpeed = speed;
+    return published;
+}
+
+void HAFan::buildSerializer()
+{
+    if (_serializer || !uniqueId()) {
+        return;
+    }
+
+    _serializer = new HASerializer(this, 24);
+    _serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(_serializer);
+    _serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(_serializer);
+    _serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    _serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (_retain) {
+        _serializer->set(
+            AHATOFSTR(HARetainProperty),
+            &_retain,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_optimistic) {
+        _serializer->set(
+            AHATOFSTR(HAOptimisticProperty),
+            &_optimistic,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_features & SpeedsFeature) {
+        _serializer->topic(AHATOFSTR(HAPercentageStateTopic));
+        _serializer->topic(AHATOFSTR(HAPercentageCommandTopic));
+
+        if (_speedRangeMax.isSet()) {
+            _serializer->set(
+                AHATOFSTR(HASpeedRangeMaxProperty),
+                &_speedRangeMax,
+                HASerializer::NumberPropertyType
+            );
+        }
+
+        if (_speedRangeMin.isSet()) {
+            _serializer->set(
+                AHATOFSTR(HASpeedRangeMinProperty),
+                &_speedRangeMin,
+                HASerializer::NumberPropertyType
+            );
+        }
+    }
+
+    _serializer->set(HASerializer::WithDevice);
+    _serializer->set(HASerializer::WithAvailability);
+    _serializer->topic(AHATOFSTR(HAStateTopic));
+    _serializer->topic(AHATOFSTR(HACommandTopic));
+}
+
+HASerializer* HAFan::buildDeviceDiscoverySerializer()
+{
+    if (!uniqueId()) {
+        return nullptr;
+    }
+
+    HASerializer* serializer = new HASerializer(this, 24);
+    serializer->set(
+        AHATOFSTR(HAPlatformProperty),
+        AHATOFSTR(HAComponentFan),
+        HASerializer::ProgmemPropertyValue
+    );
+    serializer->set(AHATOFSTR(HANameProperty), _name);
+    setEntityIdProperty(serializer);
+    serializer->set(HASerializer::WithUniqueId);
+    applyCommonEntityProperties(serializer);
+    serializer->set(AHATOFSTR(HAStateEntityCategory), nonEmptyString(_entityCategory));
+    serializer->set(AHATOFSTR(HAIconProperty), _icon);
+
+    if (_retain) {
+        serializer->set(
+            AHATOFSTR(HARetainProperty),
+            &_retain,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_optimistic) {
+        serializer->set(
+            AHATOFSTR(HAOptimisticProperty),
+            &_optimistic,
+            HASerializer::BoolPropertyType
+        );
+    }
+
+    if (_features & SpeedsFeature) {
+        serializer->topic(AHATOFSTR(HAPercentageStateTopic));
+        serializer->topic(AHATOFSTR(HAPercentageCommandTopic));
+
+        if (_speedRangeMax.isSet()) {
+            serializer->set(
+                AHATOFSTR(HASpeedRangeMaxProperty),
+                &_speedRangeMax,
+                HASerializer::NumberPropertyType
+            );
+        }
+
+        if (_speedRangeMin.isSet()) {
+            serializer->set(
+                AHATOFSTR(HASpeedRangeMinProperty),
+                &_speedRangeMin,
+                HASerializer::NumberPropertyType
+            );
+        }
+    }
+
+    serializer->set(HASerializer::WithAvailability);
+    serializer->topic(AHATOFSTR(HAStateTopic));
+    serializer->topic(AHATOFSTR(HACommandTopic));
+    return serializer;
+}
+
+void HAFan::onMqttConnected()
+{
+    if (!uniqueId()) {
+        return;
+    }
+
+    if (shouldPublishSingleComponentConfig()) {
+        publishConfig();
+    }
+    publishAvailability();
+
+    if (!_retain) {
+        publishState(_currentState);
+        publishSpeed(_currentSpeed);
+    }
+
+    subscribeTopic(uniqueId(), AHATOFSTR(HACommandTopic));
+
+    if (_features & SpeedsFeature) {
+        subscribeTopic(uniqueId(), AHATOFSTR(HAPercentageCommandTopic));
+    }
+}
+
+void HAFan::onMqttMessage(
+    const char* topic,
+    const uint8_t* payload,
+    const uint16_t length
+)
+{
+    if (HASerializer::compareDataTopics(
+        topic,
+        uniqueId(),
+        AHATOFSTR(HACommandTopic)
+    )) {
+        handleStateCommand(payload, length);
+    } else if (HASerializer::compareDataTopics(
+        topic,
+        uniqueId(),
+        AHATOFSTR(HAPercentageCommandTopic)
+    )) {
+        handleSpeedCommand(payload, length);
+    }
+}
+
+bool HAFan::publishState(const bool state)
+{
+    return publishOnDataTopic(
+        AHATOFSTR(HAStateTopic),
+        AHATOFSTR(state ? HAStateOn : HAStateOff),
+        true
+    );
+}
+
+bool HAFan::publishSpeed(const uint16_t speed)
+{
+    if (!(_features & SpeedsFeature)) {
+        return false;
+    }
+
+    char str[5 + 1] = {0}; // uint16_t digits with null terminator
+    HANumeric(speed, 0).toStr(str);
+
+    return publishOnDataTopic(AHATOFSTR(HAPercentageStateTopic), str, true);
+}
+
+void HAFan::handleStateCommand(const uint8_t* cmd, const uint16_t length)
+{
+    (void)cmd;
+
+    const bool hasStateCallback =
+        _stateCallback
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        || static_cast<bool>(_stateStdCallback)
+#endif
+    ;
+
+    if (!hasStateCallback) {
+        return;
+    }
+
+    bool state = length == strlen_P(HAStateOn);
+    if (_stateCallback) {
+        _stateCallback(state, this);
+    }
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+    if (_stateStdCallback) {
+        _stateStdCallback(state, this);
+    }
+#endif
+}
+
+void HAFan::handleSpeedCommand(const uint8_t* cmd, const uint16_t length)
+{
+    const bool hasSpeedCallback =
+        _speedCallback
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        || static_cast<bool>(_speedStdCallback)
+#endif
+    ;
+
+    if (!hasSpeedCallback) {
+        return;
+    }
+
+    const HANumeric& number = HANumeric::fromStr(cmd, length);
+    if (number.isUInt16()) {
+        const uint16_t speed = number.toUInt16();
+        if (_speedCallback) {
+            _speedCallback(speed, this);
+        }
+#if defined(ARDUINOHA_ENABLE_STDFUNCTION)
+        if (_speedStdCallback) {
+            _speedStdCallback(speed, this);
+        }
+#endif
+    }
+}
+
+#endif