Use entity class attributes for caldav (#53332)

homeassistant/components/caldav/calendar.py

@@ -119,24 +119,13 @@ class WebDavCalendarEventDevice(CalendarEventDevice):
         self.data = WebDavCalendarData(calendar, days, all_day, search)
         self.entity_id = entity_id
         self._event = None
-        self._name = name
-        self._offset_reached = False
-
-    @property
-    def extra_state_attributes(self):
-        """Return the device state attributes."""
-        return {"offset_reached": self._offset_reached}
+        self._attr_name = name
 
     @property
     def event(self):
         """Return the next upcoming event."""
         return self._event
 
-    @property
-    def name(self):
-        """Return the name of the entity."""
-        return self._name
-
     async def async_get_events(self, hass, start_date, end_date):
         """Get all events in a specific time frame."""
         return await self.data.async_get_events(hass, start_date, end_date)
@@ -149,8 +138,8 @@ class WebDavCalendarEventDevice(CalendarEventDevice):
             self._event = event
             return
         event = calculate_offset(event, OFFSET)
-        self._offset_reached = is_offset_reached(event)
         self._event = event
+        self._attr_extra_state_attributes = {"offset_reached": is_offset_reached(event)}
 
 
 class WebDavCalendarData: