Handle changes to source entities in generic_thermostat helper (home-assistant#146541)

Author: emontnemery

homeassistant/components/generic_thermostat/__init__.py

@@ -1,12 +1,16 @@
 """The generic_thermostat component."""
 
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.core import HomeAssistant
+from homeassistant.core import Event, HomeAssistant
+from homeassistant.helpers import entity_registry as er
 from homeassistant.helpers.device import (
+    async_entity_id_to_device_id,
     async_remove_stale_devices_links_keep_entity_device,
 )
+from homeassistant.helpers.event import async_track_entity_registry_updated_event
+from homeassistant.helpers.helper_integration import async_handle_source_entity_changes
 
-from .const import CONF_HEATER, PLATFORMS
+from .const import CONF_HEATER, CONF_SENSOR, PLATFORMS
 
 
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
@@ -17,6 +21,55 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         entry.entry_id,
         entry.options[CONF_HEATER],
     )
+
+    def set_humidifier_entity_id_or_uuid(source_entity_id: str) -> None:
+        hass.config_entries.async_update_entry(
+            entry,
+            options={**entry.options, CONF_HEATER: source_entity_id},
+        )
+
+    async def source_entity_removed() -> None:
+        # The source entity has been removed, we need to clean the device links.
+        async_remove_stale_devices_links_keep_entity_device(hass, entry.entry_id, None)
+
+    entry.async_on_unload(
+        # We use async_handle_source_entity_changes to track changes to the heater, but
+        # not the temperature sensor because the generic_hygrostat adds itself to the
+        # heater's device.
+        async_handle_source_entity_changes(
+            hass,
+            helper_config_entry_id=entry.entry_id,
+            set_source_entity_id_or_uuid=set_humidifier_entity_id_or_uuid,
+            source_device_id=async_entity_id_to_device_id(
+                hass, entry.options[CONF_HEATER]
+            ),
+            source_entity_id_or_uuid=entry.options[CONF_HEATER],
+            source_entity_removed=source_entity_removed,
+        )
+    )
+
+    async def async_sensor_updated(
+        event: Event[er.EventEntityRegistryUpdatedData],
+    ) -> None:
+        """Handle entity registry update."""
+        data = event.data
+        if data["action"] != "update":
+            return
+        if "entity_id" not in data["changes"]:
+            return
+
+        # Entity_id changed, update the config entry
+        hass.config_entries.async_update_entry(
+            entry,
+            options={**entry.options, CONF_SENSOR: data["entity_id"]},
+        )
+
+    entry.async_on_unload(
+        async_track_entity_registry_updated_event(
+            hass, entry.options[CONF_SENSOR], async_sensor_updated
+        )
+    )
+
     await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
     entry.async_on_unload(entry.add_update_listener(config_entry_update_listener))
     return True