Improve audio focus management (#4707)

* Extract Audio focus management to its own modules.

* Request Audio focus when playing a voice message.

* Add missing dependency.
(and remove a duplicated one)

* Request Audio focus when playing a video/audio in the media viewer.

* Pause audio when audio focus is lost.

* Rename class

* Fix tests

* Fix detekt issue.

* Audio focus: let the system handle automatic ducking when playing media.

* Document and update API

* Remove useless space.

libraries/mediaplayer/impl/src/main/kotlin/io/element/android/libraries/mediaplayer/impl/DefaultMediaPlayer.kt

@@ -11,6 +11,8 @@ import androidx.media3.common.C
 import androidx.media3.common.MediaItem
 import androidx.media3.common.Player
 import com.squareup.anvil.annotations.ContributesBinding
+import io.element.android.libraries.audio.api.AudioFocus
+import io.element.android.libraries.audio.api.AudioFocusRequester
 import io.element.android.libraries.di.RoomScope
 import io.element.android.libraries.di.SingleIn
 import io.element.android.libraries.mediaplayer.api.MediaPlayer
@@ -36,6 +38,7 @@ import kotlin.time.Duration.Companion.seconds
 class DefaultMediaPlayer @Inject constructor(
     private val player: SimplePlayer,
     private val coroutineScope: CoroutineScope,
+    private val audioFocus: AudioFocus,
 ) : MediaPlayer {
     private val listener = object : SimplePlayer.Listener {
         override fun onIsPlayingChanged(isPlaying: Boolean) {
@@ -49,6 +52,7 @@ class DefaultMediaPlayer @Inject constructor(
             if (isPlaying) {
                 job = coroutineScope.launch { updateCurrentPosition() }
             } else {
+                audioFocus.releaseAudioFocus()
                 job?.cancel()
             }
         }
@@ -118,6 +122,14 @@ class DefaultMediaPlayer @Inject constructor(
     }
 
     override fun play() {
+        audioFocus.requestAudioFocus(
+            requester = AudioFocusRequester.VoiceMessage,
+            onFocusLost = {
+                if (player.isPlaying()) {
+                    player.pause()
+                }
+            },
+        )
         if (player.playbackState == Player.STATE_ENDED) {
             // There's a bug with some ogg files that somehow report to
             // have no duration.

libraries/mediaplayer/impl/src/main/kotlin/io/element/android/libraries/mediaplayer/impl/SimplePlayer.kt

@@ -30,6 +30,7 @@ interface SimplePlayer {
     fun getCurrentMediaItem(): MediaItem?
     fun prepare()
     fun play()
+    fun isPlaying(): Boolean
     fun pause()
     fun seekTo(positionMs: Long)
     fun release()
@@ -80,6 +81,8 @@ class DefaultSimplePlayer(
 
     override fun play() = p.play()
 
+    override fun isPlaying() = p.isPlaying
+
     override fun pause() = p.pause()
 
     override fun seekTo(positionMs: Long) = p.seekTo(positionMs)

libraries/mediaplayer/impl/src/test/kotlin/io/element/android/libraries/mediaplayer/impl/DefaultMediaPlayerTest.kt

@@ -11,7 +11,10 @@ import androidx.media3.common.MediaItem
 import androidx.media3.common.Player
 import app.cash.turbine.test
 import com.google.common.truth.Truth.assertThat
+import io.element.android.libraries.audio.api.AudioFocus
+import io.element.android.libraries.audio.api.AudioFocusRequester
 import io.element.android.libraries.mediaplayer.api.MediaPlayer
+import io.element.android.libraries.mediaplayer.test.FakeAudioFocus
 import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.lambda.value
 import kotlinx.coroutines.TimeoutCancellationException
@@ -50,8 +53,15 @@ class DefaultMediaPlayerTest {
             playLambda = playLambda,
             pauseLambda = pauseLambda,
         )
+        val requestAudioFocusResult = lambdaRecorder<AudioFocusRequester, () -> Unit, Unit> { _, _ -> }
+        val releaseAudioFocusResult = lambdaRecorder<Unit> {}
+        val audioFocus = FakeAudioFocus(
+            requestAudioFocusResult = requestAudioFocusResult,
+            releaseAudioFocusResult = releaseAudioFocusResult
+        )
         val sut = createDefaultMediaPlayer(
             simplePlayer = player,
+            audioFocus = audioFocus,
         )
         sut.state.test {
             val initialState = awaitItem()
@@ -67,6 +77,7 @@ class DefaultMediaPlayerTest {
             )
             sut.play()
             playLambda.assertions().isCalledOnce()
+            requestAudioFocusResult.assertions().isCalledOnce()
             player.durationResult = 123L
             player.simulateIsPlayingChanged(true)
             val playingState = awaitItem()
@@ -105,6 +116,7 @@ class DefaultMediaPlayerTest {
             player.pause()
             pauseLambda.assertions().isCalledOnce()
             player.simulateIsPlayingChanged(false)
+            releaseAudioFocusResult.assertions().isCalledOnce()
             assertThat(awaitItem()).isEqualTo(
                 MediaPlayer.State(
                     isReady = false,
@@ -126,8 +138,13 @@ class DefaultMediaPlayerTest {
             playLambda = playLambda,
             getCurrentMediaItemLambda = getCurrentMediaItemLambda,
         )
+        val requestAudioFocusResult = lambdaRecorder<AudioFocusRequester, () -> Unit, Unit> { _, _ -> }
+        val audioFocus = FakeAudioFocus(
+            requestAudioFocusResult = requestAudioFocusResult,
+        )
         val sut = createDefaultMediaPlayer(
             simplePlayer = player,
+            audioFocus = audioFocus,
         )
         sut.state.test {
             val initialState = awaitItem()
@@ -144,6 +161,7 @@ class DefaultMediaPlayerTest {
             player.playbackStateResult = Player.STATE_ENDED
             sut.play()
             playLambda.assertions().isCalledOnce()
+            requestAudioFocusResult.assertions().isCalledOnce()
         }
     }
 
@@ -153,6 +171,10 @@ class DefaultMediaPlayerTest {
         val prepareLambda = lambdaRecorder<Unit> { }
         val getCurrentMediaItemLambda = lambdaRecorder<MediaItem?> { aMediaItem }
         val setMediaItemLambda = lambdaRecorder<MediaItem, Long, Unit> { _, _ -> }
+        val requestAudioFocusResult = lambdaRecorder<AudioFocusRequester, () -> Unit, Unit> { _, _ -> }
+        val audioFocus = FakeAudioFocus(
+            requestAudioFocusResult = requestAudioFocusResult,
+        )
         val player = FakeSimplePlayer(
             playLambda = playLambda,
             prepareLambda = prepareLambda,
@@ -161,6 +183,7 @@ class DefaultMediaPlayerTest {
         )
         val sut = createDefaultMediaPlayer(
             simplePlayer = player,
+            audioFocus = audioFocus,
         )
         sut.state.test {
             val initialState = awaitItem()
@@ -182,6 +205,7 @@ class DefaultMediaPlayerTest {
             )
             prepareLambda.assertions().isCalledOnce()
             playLambda.assertions().isCalledOnce()
+            requestAudioFocusResult.assertions().isCalledOnce()
         }
     }
 
@@ -395,8 +419,10 @@ class DefaultMediaPlayerTest {
 
     private fun TestScope.createDefaultMediaPlayer(
         simplePlayer: SimplePlayer = FakeSimplePlayer(),
+        audioFocus: AudioFocus = FakeAudioFocus(),
     ): DefaultMediaPlayer = DefaultMediaPlayer(
-        simplePlayer,
-        backgroundScope,
+        player = simplePlayer,
+        coroutineScope = backgroundScope,
+        audioFocus = audioFocus,
     )
 }

libraries/mediaplayer/impl/src/test/kotlin/io/element/android/libraries/mediaplayer/impl/FakeSimplePlayer.kt

@@ -16,6 +16,7 @@ class FakeSimplePlayer(
     private val getCurrentMediaItemLambda: () -> MediaItem? = { lambdaError() },
     private val prepareLambda: () -> Unit = { lambdaError() },
     private val playLambda: () -> Unit = { lambdaError() },
+    private val isPlayingLambda: () -> Boolean = { lambdaError() },
     private val pauseLambda: () -> Unit = { lambdaError() },
     private val seekToLambda: (Long) -> Unit = { lambdaError() },
     private val releaseLambda: () -> Unit = { lambdaError() },
@@ -40,6 +41,7 @@ class FakeSimplePlayer(
     override fun getCurrentMediaItem(): MediaItem? = getCurrentMediaItemLambda()
     override fun prepare() = prepareLambda()
     override fun play() = playLambda()
+    override fun isPlaying() = isPlayingLambda()
     override fun pause() = pauseLambda()
     override fun seekTo(positionMs: Long) = seekToLambda(positionMs)
     override fun release() = releaseLambda()