Fix media seeking flicker (#6434)

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/local/audio/MediaAudioView.kt

@@ -121,6 +121,7 @@ private fun ExoPlayerMediaAudioView(
                 durationInMillis = 0,
                 canMute = false,
                 isMuted = false,
+                seekingToMillis = null,
             )
         )
     }
@@ -171,15 +172,21 @@ private fun ExoPlayerMediaAudioView(
     LaunchedEffect(exoPlayer.isPlaying) {
         if (exoPlayer.isPlaying) {
             while (true) {
+                val position = exoPlayer.currentPosition
+                val seekingTo = mediaPlayerControllerState.seekingToMillis
                 mediaPlayerControllerState = mediaPlayerControllerState.copy(
-                    progressInMillis = exoPlayer.currentPosition,
+                    progressInMillis = position,
+                    seekingToMillis = if (seekingTo != null && position >= seekingTo) null else seekingTo,
                 )
                 delay(200)
             }
         } else {
             // Ensure we render the final state
+            val position = exoPlayer.currentPosition
+            val seekingTo = mediaPlayerControllerState.seekingToMillis
             mediaPlayerControllerState = mediaPlayerControllerState.copy(
-                progressInMillis = exoPlayer.currentPosition,
+                progressInMillis = position,
+                seekingToMillis = if (seekingTo != null && position >= seekingTo) null else seekingTo,
             )
         }
     }
@@ -294,6 +301,9 @@ private fun ExoPlayerMediaAudioView(
                 exoPlayer.togglePlay()
             },
             onSeekChange = {
+                mediaPlayerControllerState = mediaPlayerControllerState.copy(
+                    seekingToMillis = it.toLong(),
+                )
                 exoPlayer.seekToEnsurePlaying(it.toLong())
             },
             onToggleMute = {

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/local/player/MediaPlayerControllerState.kt

@@ -18,7 +18,16 @@ data class MediaPlayerControllerState(
     val durationInMillis: Long,
     val canMute: Boolean,
     val isMuted: Boolean,
+    val seekingToMillis: Long?,
 ) {
+    /**
+     * The progress in milliseconds to display. When [seekingToMillis] is non-null (during a seek operation),
+     * this returns the target seek position. Once the player catches up to the seek position,
+     * [seekingToMillis] is cleared (set to null) and this returns [progressInMillis] again.
+     */
+    val displayProgressInMillis: Long
+        get() = seekingToMillis ?: progressInMillis
+
     @FloatRange(from = 0.0, to = 1.0)
-    val progressAsFloat = (progressInMillis.toFloat() / durationInMillis.toFloat()).coerceIn(0f, 1f)
+    val progressAsFloat = (displayProgressInMillis.toFloat() / durationInMillis.toFloat()).coerceIn(0f, 1f)
 }

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/local/player/MediaPlayerControllerStateProvider.kt

@@ -34,6 +34,7 @@ private fun aMediaPlayerControllerState(
     durationInMillis: Long = 83_000,
     canMute: Boolean = true,
     isMuted: Boolean = false,
+    seekingToMillis: Long? = null,
 ) = MediaPlayerControllerState(
     isVisible = isVisible,
     isPlaying = isPlaying,
@@ -42,4 +43,5 @@ private fun aMediaPlayerControllerState(
     durationInMillis = durationInMillis,
     canMute = canMute,
     isMuted = isMuted,
+    seekingToMillis = seekingToMillis,
 )

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/local/player/MediaPlayerControllerView.kt

@@ -126,7 +126,7 @@ fun MediaPlayerControllerView(
                     modifier = Modifier
                         .widthIn(min = 48.dp)
                         .padding(horizontal = 8.dp),
-                    text = state.progressInMillis.toHumanReadableDuration(),
+                    text = state.displayProgressInMillis.toHumanReadableDuration(),
                     textAlign = TextAlign.Center,
                     color = ElementTheme.colors.textPrimary,
                     style = ElementTheme.typography.fontBodyXsMedium,
@@ -135,7 +135,9 @@ fun MediaPlayerControllerView(
                 Slider(
                     modifier = Modifier.weight(1f),
                     valueRange = 0f..state.durationInMillis.toFloat(),
-                    value = lastSelectedValue.takeIf { it >= 0 } ?: state.progressInMillis.toFloat(),
+                    value = lastSelectedValue.takeIf { it >= 0 }
+                        ?: state.seekingToMillis?.toFloat()
+                        ?: state.progressInMillis.toFloat(),
                     onValueChange = {
                         lastSelectedValue = it
                     },

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/local/video/MediaVideoView.kt

@@ -108,6 +108,7 @@ private fun ExoPlayerMediaVideoView(
                 durationInMillis = 0,
                 canMute = true,
                 isMuted = false,
+                seekingToMillis = null,
             )
         )
     }
@@ -225,6 +226,9 @@ private fun ExoPlayerMediaVideoView(
             },
             onSeekChange = {
                 autoHideController++
+                mediaPlayerControllerState = mediaPlayerControllerState.copy(
+                    seekingToMillis = it.toLong(),
+                )
                 exoPlayer.seekToEnsurePlaying(it.toLong())
             },
             onToggleMute = {
@@ -242,15 +246,21 @@ private fun ExoPlayerMediaVideoView(
     LaunchedEffect(exoPlayer.isPlaying) {
         if (exoPlayer.isPlaying) {
             while (true) {
+                val position = exoPlayer.currentPosition
+                val seekingTo = mediaPlayerControllerState.seekingToMillis
                 mediaPlayerControllerState = mediaPlayerControllerState.copy(
-                    progressInMillis = exoPlayer.currentPosition,
+                    progressInMillis = position,
+                    seekingToMillis = if (seekingTo != null && position >= seekingTo) null else seekingTo,
                 )
                 delay(200)
             }
         } else {
             // Ensure we render the final state
+            val position = exoPlayer.currentPosition
+            val seekingTo = mediaPlayerControllerState.seekingToMillis
             mediaPlayerControllerState = mediaPlayerControllerState.copy(
-                progressInMillis = exoPlayer.currentPosition,
+                progressInMillis = position,
+                seekingToMillis = if (seekingTo != null && position >= seekingTo) null else seekingTo,
             )
         }
     }