Avoid unnecessary cast state updates (#13770)

* Avoid unnecessary cast state updates

* Add test

* Fixed bad syntax

* Fixed imports

* Fixed test

homeassistant/components/media_player/cast.py

@@ -288,7 +288,8 @@ class CastDevice(MediaPlayerDevice):
         self._chromecast = None  # type: Optional[pychromecast.Chromecast]
         self.cast_status = None
         self.media_status = None
-        self.media_status_received = None
+        self.media_status_position = None
+        self.media_status_position_received = None
         self._available = False  # type: bool
         self._status_listener = None  # type: Optional[CastStatusListener]
 
@@ -361,7 +362,8 @@ class CastDevice(MediaPlayerDevice):
         self._chromecast = None
         self.cast_status = None
         self.media_status = None
-        self.media_status_received = None
+        self.media_status_position = None
+        self.media_status_position_received = None
         self._status_listener.invalidate()
         self._status_listener = None
 
@@ -388,8 +390,36 @@ class CastDevice(MediaPlayerDevice):
 
     def new_media_status(self, media_status):
         """Handle updates of the media status."""
+        # Only use media position for playing/paused,
+        # and for normal playback rate
+        if (media_status is None or
+                abs(media_status.playback_rate - 1) > 0.01 or
+                not (media_status.player_is_playing or
+                     media_status.player_is_paused)):
+            self.media_status_position = None
+            self.media_status_position_received = None
+        else:
+            # Avoid unnecessary state attribute updates if player_state and
+            # calculated position stay the same
+            now = dt_util.utcnow()
+            do_update = \
+                (self.media_status is None or
+                 self.media_status_position is None or
+                 self.media_status.player_state != media_status.player_state)
+            if not do_update:
+                if media_status.player_is_playing:
+                    elapsed = now - self.media_status_position_received
+                    do_update = abs(media_status.current_time -
+                                    (self.media_status_position +
+                                     elapsed.total_seconds())) > 1
+                else:
+                    do_update = \
+                        self.media_status_position != media_status.current_time
+            if do_update:
+                self.media_status_position = media_status.current_time
+                self.media_status_position_received = now
+
         self.media_status = media_status
-        self.media_status_received = dt_util.utcnow()
         self.schedule_update_ha_state()
 
     def new_connection_status(self, connection_status):
@@ -595,13 +625,7 @@ class CastDevice(MediaPlayerDevice):
     @property
     def media_position(self):
         """Position of current playing media in seconds."""
-        if self.media_status is None or \
+        return self.media_status_position
-                not (self.media_status.player_is_playing or
-                     self.media_status.player_is_paused or
-                     self.media_status.player_is_idle):
-            return None
-
-        return self.media_status.current_time
 
     @property
     def media_position_updated_at(self):
@@ -609,7 +633,7 @@ class CastDevice(MediaPlayerDevice):
 
         Returns value from homeassistant.util.dt.utcnow().
         """
-        return self.media_status_received
+        return self.media_status_position_received
 
     @property
     def unique_id(self) -> Optional[str]:

tests/components/media_player/test_cast.py

@@ -1,6 +1,7 @@
 """The tests for the Cast Media player platform."""
 # pylint: disable=protected-access
 import asyncio
+import datetime as dt
 from typing import Optional
 from unittest.mock import patch, MagicMock, Mock
 from uuid import UUID
@@ -14,7 +15,8 @@ from homeassistant.components.media_player.cast import ChromecastInfo
 from homeassistant.const import EVENT_HOMEASSISTANT_STOP
 from homeassistant.helpers.dispatcher import async_dispatcher_connect, \
     async_dispatcher_send
-from homeassistant.components.media_player import cast
+from homeassistant.components.media_player import cast, \
+    ATTR_MEDIA_POSITION, ATTR_MEDIA_POSITION_UPDATED_AT
 from homeassistant.setup import async_setup_component
 
 
@@ -286,6 +288,8 @@ async def test_entity_media_states(hass: HomeAssistantType):
     assert entity.unique_id == full_info.uuid
 
     media_status = MagicMock(images=None)
+    media_status.current_time = 0
+    media_status.playback_rate = 1
     media_status.player_is_playing = True
     entity.new_media_status(media_status)
     await hass.async_block_till_done()
@@ -320,6 +324,85 @@ async def test_entity_media_states(hass: HomeAssistantType):
     assert state.state == 'unknown'
 
 
+async def test_entity_media_position(hass: HomeAssistantType):
+    """Test various entity media states."""
+    info = get_fake_chromecast_info()
+    full_info = attr.evolve(info, model_name='google home',
+                            friendly_name='Speaker', uuid=FakeUUID)
+
+    with patch('pychromecast.dial.get_device_status',
+               return_value=full_info):
+        chromecast, entity = await async_setup_media_player_cast(hass, info)
+
+    media_status = MagicMock(images=None)
+    media_status.current_time = 10
+    media_status.playback_rate = 1
+    media_status.player_is_playing = True
+    media_status.player_is_paused = False
+    media_status.player_is_idle = False
+    now = dt.datetime.now(dt.timezone.utc)
+    with patch('homeassistant.util.dt.utcnow', return_value=now):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert state.attributes[ATTR_MEDIA_POSITION] == 10
+    assert state.attributes[ATTR_MEDIA_POSITION_UPDATED_AT] == now
+
+    media_status.current_time = 15
+    now_plus_5 = now + dt.timedelta(seconds=5)
+    with patch('homeassistant.util.dt.utcnow', return_value=now_plus_5):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert state.attributes[ATTR_MEDIA_POSITION] == 10
+    assert state.attributes[ATTR_MEDIA_POSITION_UPDATED_AT] == now
+
+    media_status.current_time = 20
+    with patch('homeassistant.util.dt.utcnow', return_value=now_plus_5):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert state.attributes[ATTR_MEDIA_POSITION] == 20
+    assert state.attributes[ATTR_MEDIA_POSITION_UPDATED_AT] == now_plus_5
+
+    media_status.current_time = 25
+    now_plus_10 = now + dt.timedelta(seconds=10)
+    media_status.player_is_playing = False
+    media_status.player_is_paused = True
+    with patch('homeassistant.util.dt.utcnow', return_value=now_plus_10):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert state.attributes[ATTR_MEDIA_POSITION] == 25
+    assert state.attributes[ATTR_MEDIA_POSITION_UPDATED_AT] == now_plus_10
+
+    now_plus_15 = now + dt.timedelta(seconds=15)
+    with patch('homeassistant.util.dt.utcnow', return_value=now_plus_15):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert state.attributes[ATTR_MEDIA_POSITION] == 25
+    assert state.attributes[ATTR_MEDIA_POSITION_UPDATED_AT] == now_plus_10
+
+    media_status.current_time = 30
+    now_plus_20 = now + dt.timedelta(seconds=20)
+    with patch('homeassistant.util.dt.utcnow', return_value=now_plus_20):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert state.attributes[ATTR_MEDIA_POSITION] == 30
+    assert state.attributes[ATTR_MEDIA_POSITION_UPDATED_AT] == now_plus_20
+
+    media_status.player_is_paused = False
+    media_status.player_is_idle = True
+    with patch('homeassistant.util.dt.utcnow', return_value=now_plus_20):
+        entity.new_media_status(media_status)
+        await hass.async_block_till_done()
+    state = hass.states.get('media_player.speaker')
+    assert ATTR_MEDIA_POSITION not in state.attributes
+    assert ATTR_MEDIA_POSITION_UPDATED_AT not in state.attributes
+
+
 async def test_switched_host(hass: HomeAssistantType):
     """Test cast device listens for changed hosts and disconnects old cast."""
     info = get_fake_chromecast_info()