Implement MQTT event groups

firmware/esp32/main/mqtt.cpp

@@ -8,6 +8,23 @@
 
 static const char* TAG = "MQTT";
 
+const int MQTT_CONNECTED_BIT = BIT0;
+
+static void mqtt_event_handler(void *handler_args, esp_event_base_t base, int32_t event_id, void *event_data) {
+    esp_mqtt_event_handle_t event = event_data;
+    switch (event->event_id) {
+        case MQTT_EVENT_CONNECTED:
+            xEventGroupSetBits(connectivity_event_group, MQTT_CONNECTED_BIT);
+            ESP_LOGI(TAG, "Connected to broker");
+            break;
+        case MQTT_EVENT_DISCONNECTED:
+            xEventGroupClearBits(connectivity_event_group, MQTT_CONNECTED_BIT);
+            ESP_LOGI(TAG, "Disconnected from broker");
+            break;
+        default:
+            break;
+    }
+}
 
 static void mqtt_init(void) {
     // TODO; implement Trust only or Mutual TLS in the future (and secure boot + flash encryption)
@@ -31,8 +48,6 @@ static void mqtt_subscribe(void) {
 
 static void mqtt_publish(void) {}
 
-static void mqtt_fetch(void) {}
-
 void mqttTask(void *pvParameters) {
     ESP_LOGI(TAG, "Task started");
 
@@ -40,13 +55,10 @@ void mqttTask(void *pvParameters) {
     ESP_ERROR_CHECK(esp_task_wdt_add(NULL));
 
     for(;;) {
-        ESP_LOGI(TAG, "Checking Wi-Fi connection...");
-        xEventGroupWaitBits(wifi_event_group, WIFI_CONNECTED_BIT, pdFALSE, pdTRUE, portMAX_DELAY);
+        ESP_LOGI(TAG, "Checking broker connection...");
 
-        if (bits & WIFI_CONNECTED_BIT) {
-            mqtt_publish();
-            mqtt_fetch();
-        }
+        if(bits && MQTT_CONNECTED_BIT) mqtt_publish();
+        else ESP_LOGW(TAG, "Waiting for connection...");
 
         ESP_ERROR_CHECK(esp_task_wdt_reset());
         ESP_LOGI(TAG, "Task reset");