Refactor ArduinoHA logging and add MQTT diagnostics.

Move ArduinoHA to a structured, runtime-configurable log model and instrument HAMqtt with disconnect and publish failure telemetry so ESP8266 MQTT failures can be diagnosed without patching PubSubClient first.

src/ArduinoHALog.cpp

@@ -1,6 +1,15 @@
 #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;
@@ -9,3 +18,80 @@ void arduinoHASetLogSink(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);
+}