Voice message scrubbing improvements (#1847)

- Voice messages can be scrubbed (i.e. seeked to) even when they have not been played yet..
- The progress bar is displayed also when paused.
- Multiple voice messages can keep their state when paused.
- Tries to adhere as much as possible at the detailed "green cursor" behavior in the story (but might not be 100% compliant).

Story: https://github.com/vector-im/element-meta/issues/2113

libraries/mediaplayer/api/src/main/kotlin/io/element/android/libraries/mediaplayer/api/MediaPlayer.kt

@@ -38,6 +38,7 @@ interface MediaPlayer : AutoCloseable {
         uri: String,
         mediaId: String,
         mimeType: String,
+        startPositionMs: Long = 0,
     ): State
 
     /**
@@ -69,6 +70,10 @@ interface MediaPlayer : AutoCloseable {
          * Whether the player is currently playing.
          */
         val isPlaying: Boolean,
+        /**
+         * Whether the player has reached the end of the current media.
+         */
+        val isEnded: Boolean,
         /**
          * The id of the media which is currently playing.
          *

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

@@ -77,6 +77,7 @@ class MediaPlayerImpl @Inject constructor(
             _state.update {
                 it.copy(
                     isReady = playbackState == Player.STATE_READY,
+                    isEnded = playbackState == Player.STATE_ENDED,
                     currentPosition = player.currentPosition,
                     duration = duration,
                 )
@@ -95,16 +96,22 @@ class MediaPlayerImpl @Inject constructor(
         MediaPlayer.State(
             isReady = false,
             isPlaying = false,
+            isEnded = false,
             mediaId = null,
             currentPosition = 0L,
-            duration = 0L
+            duration = null,
         )
     )
 
     override val state: StateFlow<MediaPlayer.State> = _state.asStateFlow()
 
     @OptIn(FlowPreview::class)
-    override suspend fun setMedia(uri: String, mediaId: String, mimeType: String): MediaPlayer.State {
+    override suspend fun setMedia(
+        uri: String,
+        mediaId: String,
+        mimeType: String,
+        startPositionMs: Long,
+    ): MediaPlayer.State {
         player.pause() // Must pause here otherwise if the player was playing it would keep on playing the new media item.
         player.clearMediaItems()
         player.setMediaItem(
@@ -112,7 +119,8 @@ class MediaPlayerImpl @Inject constructor(
                 .setUri(uri)
                 .setMediaId(mediaId)
                 .setMimeType(mimeType)
-                .build()
+                .build(),
+            startPositionMs,
         )
         player.prepare()
         // Will throw TimeoutCancellationException if the player is not ready after 1 second.
@@ -129,7 +137,7 @@ class MediaPlayerImpl @Inject constructor(
             // playing no sound.
             // This is a workaround which will reload the media file.
             player.getCurrentMediaItem()?.let {
-                player.setMediaItem(it)
+                player.setMediaItem(it, 0)
                 player.prepare()
                 player.play()
             }

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

@@ -35,7 +35,7 @@ interface SimplePlayer {
     val playbackState: Int
     val duration: Long
     fun clearMediaItems()
-    fun setMediaItem(mediaItem: MediaItem)
+    fun setMediaItem(mediaItem: MediaItem, startPositionMs: Long)
     fun getCurrentMediaItem(): MediaItem?
     fun prepare()
     fun play()
@@ -81,7 +81,7 @@ class SimplePlayerImpl(
 
     override fun clearMediaItems() = p.clearMediaItems()
 
-    override fun setMediaItem(mediaItem: MediaItem) = p.setMediaItem(mediaItem)
+    override fun setMediaItem(mediaItem: MediaItem, startPositionMs: Long) = p.setMediaItem(mediaItem, startPositionMs)
 
     override fun getCurrentMediaItem(): MediaItem? = p.currentMediaItem
 

libraries/mediaplayer/test/src/main/kotlin/io/element/android/libraries/mediaplayer/test/FakeMediaPlayer.kt

@@ -26,31 +26,37 @@ import kotlinx.coroutines.flow.update
 /**
  * Fake implementation of [MediaPlayer] for testing purposes.
  */
-class FakeMediaPlayer : MediaPlayer {
-    companion object {
-        private const val FAKE_TOTAL_DURATION_MS = 10_000L
-        private const val FAKE_PLAYED_DURATION_MS = 1000L
-    }
+class FakeMediaPlayer(
+    private val fakeTotalDurationMs: Long = 10_000L,
+    private val fakePlayedDurationMs: Long = 1000L,
+) : MediaPlayer {
 
     private val _state = MutableStateFlow(
         MediaPlayer.State(
             isReady = false,
             isPlaying = false,
+            isEnded = false,
             mediaId = null,
             currentPosition = 0L,
-            duration = 0L
+            duration = null
         )
     )
 
     override val state: StateFlow<MediaPlayer.State> = _state.asStateFlow()
 
-    override suspend fun setMedia(uri: String, mediaId: String, mimeType: String): MediaPlayer.State {
+    override suspend fun setMedia(
+        uri: String,
+        mediaId: String,
+        mimeType: String,
+        startPositionMs: Long,
+    ): MediaPlayer.State {
         _state.update {
             it.copy(
                 isReady = false,
                 isPlaying = false,
+                isEnded = false,
                 mediaId = mediaId,
-                currentPosition = 0,
+                currentPosition = startPositionMs,
                 duration = null,
             )
         }
@@ -58,7 +64,7 @@ class FakeMediaPlayer : MediaPlayer {
         _state.update {
             it.copy(
                 isReady = true,
-                duration = FAKE_TOTAL_DURATION_MS,
+                duration = fakeTotalDurationMs,
             )
         }
         return _state.value
@@ -66,10 +72,20 @@ class FakeMediaPlayer : MediaPlayer {
 
     override fun play() {
         _state.update {
-            it.copy(
-                isPlaying = true,
-                currentPosition = it.currentPosition + FAKE_PLAYED_DURATION_MS,
-            )
+            val newPosition = it.currentPosition + fakePlayedDurationMs
+            if (newPosition < fakeTotalDurationMs) {
+                it.copy(
+                    isPlaying = true,
+                    currentPosition = newPosition,
+                )
+            } else {
+                it.copy(
+                    isReady = false,
+                    isPlaying = false,
+                    isEnded = true,
+                    currentPosition = fakeTotalDurationMs,
+                )
+            }
         }
     }