Support for statistics from sensors in HA (#179)

* Fix statistics from sensors

* Test for state class setter in HASensor

src/device-types/HASensor.cpp

@@ -7,6 +7,7 @@
 HASensor::HASensor(const char* uniqueId) :
     HABaseDeviceType(AHATOFSTR(HAComponentSensor), uniqueId),
     _deviceClass(nullptr),
+    _stateClass(nullptr),
     _forceUpdate(false),
     _icon(nullptr),
     _unitOfMeasurement(nullptr)
@@ -25,10 +26,11 @@ void HASensor::buildSerializer()
         return;
     }
 
-    _serializer = new HASerializer(this, 9); // 9 - max properties nb
+    _serializer = new HASerializer(this, 10); // 10 - max properties nb
     _serializer->set(AHATOFSTR(HANameProperty), _name);
     _serializer->set(AHATOFSTR(HAUniqueIdProperty), _uniqueId);
     _serializer->set(AHATOFSTR(HADeviceClassProperty), _deviceClass);
+    _serializer->set(AHATOFSTR(HAStateClassProperty), _stateClass);
     _serializer->set(AHATOFSTR(HAIconProperty), _icon);
     _serializer->set(AHATOFSTR(HAUnitOfMeasurementProperty), _unitOfMeasurement);
 

src/device-types/HASensor.h

@@ -41,6 +41,15 @@ public:
     inline void setDeviceClass(const char* deviceClass)
         { _deviceClass = deviceClass; }
 
+    /**
+     * Sets class of the state for the long term stats.
+     * See: https://developers.home-assistant.io/docs/core/entity/sensor/#long-term-statistics
+     *
+     * @param stateClass The class name.
+     */
+    inline void setStateClass(const char* stateClass)
+        { _stateClass = stateClass; }
+
     /**
      * Forces HA panel to process each incoming value (MQTT message).
      * It's useful if you want to have meaningful value graphs in history.
@@ -74,6 +83,9 @@ protected:
 private:
     /// The device class. It can be nullptr.
     const char* _deviceClass;
+	
+    /// The state class for the long term stats. It can be nullptr. See: https://developers.home-assistant.io/docs/core/entity/sensor/#long-term-statistics
+    const char* _stateClass;
 
     /// The force update flag for the HA panel.
     bool _forceUpdate;

src/utils/HADictionary.cpp

@@ -40,6 +40,7 @@ const char HANameProperty[] PROGMEM = {"name"};
 const char HAUniqueIdProperty[] PROGMEM = {"uniq_id"};
 const char HADeviceProperty[] PROGMEM = {"dev"};
 const char HADeviceClassProperty[] PROGMEM = {"dev_cla"};
+const char HAStateClassProperty[] PROGMEM = {"state_class"};
 const char HAIconProperty[] PROGMEM = {"ic"};
 const char HARetainProperty[] PROGMEM = {"ret"};
 const char HASourceTypeProperty[] PROGMEM = {"src_type"};

src/utils/HADictionary.h

@@ -40,6 +40,7 @@ extern const char HANameProperty[];
 extern const char HAUniqueIdProperty[];
 extern const char HADeviceProperty[];
 extern const char HADeviceClassProperty[];
+extern const char HAStateClassProperty[];
 extern const char HAIconProperty[];
 extern const char HARetainProperty[];
 extern const char HASourceTypeProperty[];

tests/SensorTest/SensorTest.ino

@@ -92,6 +92,26 @@ AHA_TEST(SensorTest, device_class_setter) {
     )
 }
 
+AHA_TEST(SensorTest, state_class_setter) {
+    initMqttTest(testDeviceId)
+
+    HASensor sensor(testUniqueId);
+    sensor.setStateClass("measurement");
+
+    assertEntityConfig(
+        mock,
+        sensor,
+        (
+            "{"
+            "\"uniq_id\":\"uniqueSensor\","
+            "\"state_class\":\"measurement\","
+            "\"dev\":{\"ids\":\"testDevice\"},"
+            "\"stat_t\":\"testData/testDevice/uniqueSensor/stat_t\""
+            "}"
+        )
+    )
+}
+
 AHA_TEST(SensorTest, force_update_setter) {
     initMqttTest(testDeviceId)