Add Pico communication timeout tracking

pico-dashboard/comms/communication_service.py

@@ -8,12 +8,32 @@ from .protocol import (
 
 
 class CommunicationService:
-    def __init__(self, uart_client, app_state, http_client=None):
+    def __init__(
+        self,
+        uart_client,
+        app_state,
+        http_client=None,
+        clock=None,
+        timeout_seconds=5,
+    ):
         self.uart_client = uart_client
         self.http_client = http_client
         self.app_state = app_state
+        self.clock = clock
+        self.timeout_seconds = timeout_seconds
         self.last_messages = []
         self.use_http_fallback = False
+        self.last_status_received_at = None
+
+    def now(self):
+        if self.clock:
+            return self.clock()
+
+        try:
+            import time
+            return time.time()
+        except ImportError:
+            return 0
 
     def request_status(self):
         if self.use_http_fallback and self.http_client:
@@ -40,8 +60,28 @@ class CommunicationService:
         for message in messages:
             self.handle_message(message)
 
+        self.update_connection_state()
+
         return messages
 
+    def update_connection_state(self):
+        if self.last_status_received_at is None:
+            self.app_state.network["uart_connected"] = False
+            return
+
+        age = self.now() - self.last_status_received_at
+        self.app_state.network["uart_connected"] = age <= self.timeout_seconds
+
+    def should_use_http_fallback(self):
+        return (
+            self.http_client is not None
+            and not self.app_state.network.get("uart_connected", False)
+        )
+
+    def auto_select_transport(self):
+        self.use_http_fallback = self.should_use_http_fallback()
+        return self.use_http_fallback
+
     def enable_http_fallback(self):
         self.use_http_fallback = True
 
@@ -50,7 +90,9 @@ class CommunicationService:
 
     def handle_message(self, message):
         if is_status_response(message):
+            self.last_status_received_at = self.now()
             self.app_state.update_from_status(message)
+            self.app_state.network["uart_connected"] = True
             return
 
         if is_relay_response(message):