Fix switchbot not becoming available again after unavailable (#81822)

* Fix switchbot not becoming available again after unavailable

If the advertisment was the same and we were previously
marked as unavailable we would not mark the device as
available again until the advertisment changed. For lights
there is a counter but for the bots there is no counter
which means the bots would show unavailable even though
they were available again

* naming

* naming

homeassistant/components/switchbot/coordinator.py

@@ -61,6 +61,15 @@ class SwitchbotDataUpdateCoordinator(PassiveBluetoothDataUpdateCoordinator):
         self.base_unique_id = base_unique_id
         self.model = model
         self._ready_event = asyncio.Event()
+        self._was_unavailable = True
+
+    @callback
+    def _async_handle_unavailable(
+        self, service_info: bluetooth.BluetoothServiceInfoBleak
+    ) -> None:
+        """Handle the device going unavailable."""
+        super()._async_handle_unavailable(service_info)
+        self._was_unavailable = True
 
     @callback
     def _async_handle_bluetooth_event(
@@ -70,16 +79,20 @@ class SwitchbotDataUpdateCoordinator(PassiveBluetoothDataUpdateCoordinator):
     ) -> None:
         """Handle a Bluetooth event."""
         self.ble_device = service_info.device
-        if adv := switchbot.parse_advertisement_data(
-            service_info.device, service_info.advertisement
+        if not (
+            adv := switchbot.parse_advertisement_data(
+                service_info.device, service_info.advertisement
+            )
         ):
-            if "modelName" in adv.data:
-                self._ready_event.set()
-            _LOGGER.debug("%s: Switchbot data: %s", self.ble_device.address, self.data)
-            if not self.device.advertisement_changed(adv):
-                return
-            self.data = flatten_sensors_data(adv.data)
-            self.device.update_from_advertisement(adv)
+            return
+        if "modelName" in adv.data:
+            self._ready_event.set()
+        _LOGGER.debug("%s: Switchbot data: %s", self.ble_device.address, self.data)
+        if not self.device.advertisement_changed(adv) and not self._was_unavailable:
+            return
+        self._was_unavailable = False
+        self.data = flatten_sensors_data(adv.data)
+        self.device.update_from_advertisement(adv)
         super()._async_handle_bluetooth_event(service_info, change)
 
     async def async_wait_ready(self) -> bool: