Simplify schedule caching to a single staleness check

The per-control-system timestamp dict was more bookkeeping than the
job needs: the app handles one location and fetches all its schedules
together. Track a single fetched-at timestamp instead, set only after
every system fetched successfully.

https://claude.ai/code/session_01RcVkTvidSn9HgsFazrfdZW

Author: claude

src/evohome_helper/evohome.py

@@ -33,7 +33,7 @@
 
 # schedules rarely change; refetching them every cycle wastes the vendor's tight API rate limit
 _SCHEDULE_REFRESH_INTERVAL = timedelta(hours=1)
-_schedule_refresh_times: dict[str, datetime] = {}
+_schedules_fetched_at: datetime | None = None
 
 _AWAY_MODE_MAP = {
     "auto": SystemMode.AUTO,
@@ -75,9 +75,9 @@ async def save_access_token(self) -> None:
 
 
 async def close() -> None:
-    global _evohome_client, _websession
+    global _evohome_client, _websession, _schedules_fetched_at
 
-    _schedule_refresh_times.clear()
+    _schedules_fetched_at = None
     _evohome_client = None
 
     if _websession is not None:
@@ -134,12 +134,18 @@ async def _update_location(location: Location) -> None:
 @_retry
 async def _fetch_schedules(system: ControlSystem) -> None:
     await system.get_schedules()
-    _schedule_refresh_times[system.id] = datetime.now()
 
 
-def _schedules_need_refresh(system: ControlSystem) -> bool:
-    last_refresh = _schedule_refresh_times.get(system.id)
-    return last_refresh is None or datetime.now() - last_refresh >= _SCHEDULE_REFRESH_INTERVAL
+async def _fetch_schedules_if_stale(location: Location) -> None:
+    global _schedules_fetched_at
+
+    if _schedules_fetched_at is not None and datetime.now() - _schedules_fetched_at < _SCHEDULE_REFRESH_INTERVAL:
+        return
+
+    await asyncio.gather(
+        *[_fetch_schedules(system) for system in get_control_systems(location)],
+    )
+    _schedules_fetched_at = datetime.now()
 
 
 async def get_location(location_name: str | None = None) -> Location:
@@ -150,13 +156,7 @@ async def get_location(location_name: str | None = None) -> Location:
     for location in client.locations:
         if location.name == location_name:
             await _update_location(location)
-            await asyncio.gather(
-                *[
-                    _fetch_schedules(system)
-                    for system in get_control_systems(location)
-                    if _schedules_need_refresh(system)
-                ],
-            )
+            await _fetch_schedules_if_stale(location)
             return location
 
     raise LocationNotFound(location_name)

tests/conftest.py

@@ -168,7 +168,7 @@ async def reset_state():
 
     presence.last_known_presence_state.clear()
     evohome._evohome_client = None
-    evohome._schedule_refresh_times.clear()
+    evohome._schedules_fetched_at = None
 
     yield
 

tests/test_evohome.py

@@ -391,16 +391,16 @@ async def test_get_location_refetches_schedules_after_refresh_interval(evohome_c
     state = evohome_client()
 
     await evohome.get_location()
-    evohome._schedule_refresh_times[state.control_system.id] -= evohome._SCHEDULE_REFRESH_INTERVAL
+    evohome._schedules_fetched_at -= evohome._SCHEDULE_REFRESH_INTERVAL
     await evohome.get_location()
 
     assert state.control_system.get_schedules.await_count == 2
 
 
 async def test_close_invalidates_schedule_cache(evohome_client):
-    state = evohome_client()
+    evohome_client()
     await evohome.get_location()
 
     await evohome.close()
 
-    assert evohome._schedule_refresh_times == {}
+    assert evohome._schedules_fetched_at is None