feat: add background task to log state transitions

Co-authored-by: aider (gemini/gemini-2.5-pro-preview-05-06) <aider@aider.chat>

server.py

@@ -31,6 +31,7 @@ REQUEST_TIMEOUT_SECONDS = 5
 UNSURE_CONFIDENCE_THRESHOLD = 0.97
 PREDICTION_HISTORY = []
 PREDICTION_HISTORY_MAX_LENGTH = 3
+PREVIOUS_STATE = "unknown"
 
 # --- Model Inference ---
 def get_prediction(model, image_bytes, device):
@@ -126,21 +127,44 @@ async def monitor_garage_door(app):
             await asyncio.sleep(5)
 
 
+async def monitor_state_transitions(app):
+    """Periodically checks for state transitions and logs them."""
+    global PREVIOUS_STATE
+    logging.info("Starting state transition monitoring task.")
+    while True:
+        try:
+            await asyncio.sleep(5)
+            current_state = get_derived_state()
+            if current_state != "unknown" and current_state != PREVIOUS_STATE:
+                logging.info(f"State transitioned from '{PREVIOUS_STATE}' to '{current_state}'.")
+            PREVIOUS_STATE = current_state
+        except asyncio.CancelledError:
+            logging.info("State transition monitoring task cancelled.")
+            break
+        except Exception as e:
+            logging.error(f"An unexpected error occurred in the state monitoring task: {e}", exc_info=True)
+            await asyncio.sleep(5)
+
+
 # --- Web Server ---
+def get_derived_state():
+    """Derives the state from the prediction history."""
+    state = "unknown"
+    if len(PREDICTION_HISTORY) == PREDICTION_HISTORY_MAX_LENGTH:
+        if all(s == "open" for s in PREDICTION_HISTORY):
+            state = "open"
+        elif all(s == "closed" for s in PREDICTION_HISTORY):
+            state = "closed"
+    return state
+
+
 async def handle_root(request):
     """Handler for the root GET request."""
     return web.Response(text="hello world")
 
 async def handle_state(request):
     """Handler for the /state GET request."""
-    state = "unknown"
-
-    if len(PREDICTION_HISTORY) == PREDICTION_HISTORY_MAX_LENGTH:
-        if all(s == "open" for s in PREDICTION_HISTORY):
-            state = "open"
-        elif all(s == "closed" for s in PREDICTION_HISTORY):
-            state = "closed"
-
+    state = get_derived_state()
     return web.Response(text=state)
 
 async def on_startup(app):
@@ -162,13 +186,16 @@ async def on_startup(app):
 
     # Start background task
     app['monitor_task'] = asyncio.create_task(monitor_garage_door(app))
+    app['state_monitor_task'] = asyncio.create_task(monitor_state_transitions(app))
 
 async def on_cleanup(app):
     """Actions to perform on application cleanup."""
     logging.info("Cleaning up...")
     app['monitor_task'].cancel()
+    app['state_monitor_task'].cancel()
     try:
         await app['monitor_task']
+        await app['state_monitor_task']
     except asyncio.CancelledError:
         pass
     await app['client_session'].close()