Fetch existing retained snapshot upon initial connection

- Added logic to request the retained snapshot message upon MQTT connection.
- Ensure initial snapshot is processed after connecting to the MQTT broker.
- Improved debugging logs for better traceability.

dayglo_detector/dayglo_detector.py

@@ -22,6 +22,9 @@ last_rating = 0
 LOWER_COLOR = np.array([20, 100, 100])
 UPPER_COLOR = np.array([40, 255, 255])
 
+# Track if the initial snapshot has been processed
+initial_snapshot_processed = False
+
 def on_connect(client, userdata, flags, rc):
     if rc == 0:
         print("Connected successfully to MQTT broker")
@@ -30,6 +33,8 @@ def on_connect(client, userdata, flags, rc):
         publish_discovery_configurations()
         # Publish initial rating of 0
         publish_rating(0)
+        # Request the retained snapshot to process the initial image
+        client.publish(MQTT_SNAPSHOT_TOPIC, "", qos=1)
     else:
         print(f"Failed to connect, return code {rc}")
 
@@ -50,9 +55,11 @@ def publish_rating(rating):
     client.publish(MQTT_TOPIC_PUBLISH, json.dumps({"rating": rating}))
 
 def on_message(client, userdata, msg):
+    global initial_snapshot_processed
     if msg.topic == MQTT_SNAPSHOT_TOPIC:
         print("Snapshot received")
         process_snapshot(msg.payload)
+        initial_snapshot_processed = True
 
 def process_snapshot(payload):
     if not payload: