Add video autoplay to media gallery (#4499)

* Add video autoplay when opening the video from either the timeline or the media gallery

* Only autoplay when the video is first displayed

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/datasource/MediaGalleryDataSource.kt

@@ -19,6 +19,7 @@ import io.element.android.libraries.mediaviewer.impl.model.GroupedMediaItems
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.launchIn
@@ -85,11 +86,13 @@ class TimelineMediaGalleryDataSource @Inject constructor(
             }
         }.flatMapLatest {
             timelineMediaItemsFactory.timelineItems
-        }.map { timelineItems ->
-            mediaItemsPostProcessor.process(mediaItems = timelineItems)
-        }.map {
-            mediaTimeline.orCache(it)
-        }.onEach { groupedMediaItems ->
+        }
+        .distinctUntilChanged()
+        .map { timelineItems ->
+            val groupedItems = mediaItemsPostProcessor.process(mediaItems = timelineItems)
+            mediaTimeline.orCache(groupedItems)
+        }
+        .onEach { groupedMediaItems ->
             groupedMediaItemsFlow.emit(AsyncData.Success(groupedMediaItems))
         }
             .onCompletion {

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

@@ -31,6 +31,7 @@ fun LocalMediaView(
     textFileViewer: TextFileViewer,
     modifier: Modifier = Modifier,
     isDisplayed: Boolean = true,
+    isUserSelected: Boolean = false,
     localMediaViewState: LocalMediaViewState = rememberLocalMediaViewState(),
     mediaInfo: MediaInfo? = localMedia?.info,
 ) {
@@ -47,6 +48,7 @@ fun LocalMediaView(
             localMediaViewState = localMediaViewState,
             bottomPaddingInPixels = bottomPaddingInPixels,
             localMedia = localMedia,
+            autoplay = isUserSelected,
             modifier = modifier,
         )
         mimeType == MimeTypes.PlainText -> TextFileView(

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

@@ -111,6 +111,7 @@ private fun ExoPlayerMediaAudioView(
             MediaPlayerControllerState(
                 isVisible = true,
                 isPlaying = false,
+                isReady = false,
                 progressInMillis = 0,
                 durationInMillis = 0,
                 canMute = false,

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

@@ -12,6 +12,7 @@ import androidx.annotation.FloatRange
 data class MediaPlayerControllerState(
     val isVisible: Boolean,
     val isPlaying: Boolean,
+    val isReady: Boolean,
     val progressInMillis: Long,
     val durationInMillis: Long,
     val canMute: Boolean,

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

@@ -27,6 +27,7 @@ open class MediaPlayerControllerStateProvider : PreviewParameterProvider<MediaPl
 private fun aMediaPlayerControllerState(
     isVisible: Boolean = true,
     isPlaying: Boolean = false,
+    isReady: Boolean = false,
     progressInMillis: Long = 0,
     // Default to 1 minute and 23 seconds
     durationInMillis: Long = 83_000,
@@ -35,6 +36,7 @@ private fun aMediaPlayerControllerState(
 ) = MediaPlayerControllerState(
     isVisible = isVisible,
     isPlaying = isPlaying,
+    isReady = isReady,
     progressInMillis = progressInMillis,
     durationInMillis = durationInMillis,
     canMute = canMute,

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

@@ -31,6 +31,7 @@ import androidx.compose.ui.viewinterop.AndroidView
 import androidx.lifecycle.Lifecycle
 import androidx.media3.common.MediaItem
 import androidx.media3.common.Player
+import androidx.media3.common.Player.STATE_READY
 import androidx.media3.common.Timeline
 import androidx.media3.exoplayer.ExoPlayer
 import androidx.media3.ui.AspectRatioFrameLayout
@@ -61,6 +62,7 @@ fun MediaVideoView(
     localMediaViewState: LocalMediaViewState,
     bottomPaddingInPixels: Int,
     localMedia: LocalMedia?,
+    autoplay: Boolean,
     modifier: Modifier = Modifier,
 ) {
     val exoPlayer = rememberExoPlayer()
@@ -70,6 +72,7 @@ fun MediaVideoView(
         bottomPaddingInPixels = bottomPaddingInPixels,
         exoPlayer = exoPlayer,
         localMedia = localMedia,
+        autoplay = autoplay,
         modifier = modifier,
     )
 }
@@ -82,6 +85,7 @@ private fun ExoPlayerMediaVideoView(
     bottomPaddingInPixels: Int,
     exoPlayer: ExoPlayer,
     localMedia: LocalMedia?,
+    autoplay: Boolean,
     modifier: Modifier = Modifier,
 ) {
     var mediaPlayerControllerState: MediaPlayerControllerState by remember {
@@ -89,6 +93,7 @@ private fun ExoPlayerMediaVideoView(
             MediaPlayerControllerState(
                 isVisible = true,
                 isPlaying = false,
+                isReady = false,
                 progressInMillis = 0,
                 durationInMillis = 0,
                 canMute = true,
@@ -135,6 +140,12 @@ private fun ExoPlayerMediaVideoView(
                         }
                 }
             }
+
+            override fun onPlaybackStateChanged(playbackState: Int) {
+                mediaPlayerControllerState = mediaPlayerControllerState.copy(
+                    isReady = playbackState == STATE_READY,
+                )
+            }
         }
     }
 
@@ -164,9 +175,17 @@ private fun ExoPlayerMediaVideoView(
             )
         }
     }
-    LaunchedEffect(isDisplayed) {
-        // If not displayed, make sure to pause the video
-        if (!isDisplayed) {
+
+    var needsAutoPlay by remember { mutableStateOf(autoplay) }
+
+    LaunchedEffect(needsAutoPlay, isDisplayed, mediaPlayerControllerState.isReady) {
+        val isReadyAndNotPlaying = mediaPlayerControllerState.isReady && !mediaPlayerControllerState.isPlaying
+        if (needsAutoPlay && isDisplayed && isReadyAndNotPlaying) {
+            // When displayed, start autoplaying
+            exoPlayer.play()
+            needsAutoPlay = false
+        } else if (!isDisplayed && mediaPlayerControllerState.isPlaying) {
+            // If not displayed, make sure to pause the video
             exoPlayer.pause()
         }
     }
@@ -259,5 +278,6 @@ internal fun MediaVideoViewPreview() = ElementPreview {
         bottomPaddingInPixels = 0,
         localMediaViewState = rememberLocalMediaViewState(),
         localMedia = null,
+        autoplay = false,
     )
 }

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerDataSource.kt

@@ -76,7 +76,7 @@ class MediaViewerDataSource(
     }
 
     @VisibleForTesting
-    fun dataFlow(): Flow<PersistentList<MediaViewerPageData>> {
+    internal fun dataFlow(): Flow<PersistentList<MediaViewerPageData>> {
         return galleryDataSource.groupedMediaItemsFlow()
             .map { groupedItems ->
                 when (groupedItems) {

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerPresenter.kt

@@ -148,6 +148,7 @@ class MediaViewerPresenter @AssistedInject constructor(
         }
 
         return MediaViewerState(
+            initiallySelectedEventId = inputs.eventId,
             listData = data.value,
             currentIndex = currentIndex.intValue,
             snackbarMessage = snackbarMessage,

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerState.kt

@@ -19,6 +19,7 @@ import io.element.android.libraries.mediaviewer.impl.details.MediaBottomSheetSta
 import kotlinx.collections.immutable.ImmutableList
 
 data class MediaViewerState(
+    val initiallySelectedEventId: EventId?,
     val listData: ImmutableList<MediaViewerPageData>,
     val currentIndex: Int,
     val snackbarMessage: SnackbarMessage?,

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerStateProvider.kt

@@ -12,6 +12,7 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import io.element.android.libraries.architecture.AsyncData
 import io.element.android.libraries.designsystem.components.media.aWaveForm
+import io.element.android.libraries.matrix.api.core.EventId
 import io.element.android.libraries.matrix.api.media.MediaSource
 import io.element.android.libraries.matrix.api.timeline.Timeline
 import io.element.android.libraries.mediaviewer.api.MediaInfo
@@ -202,6 +203,7 @@ fun aMediaViewerState(
     mediaBottomSheetState: MediaBottomSheetState = MediaBottomSheetState.Hidden,
     eventSink: (MediaViewerEvents) -> Unit = {},
 ) = MediaViewerState(
+    initiallySelectedEventId = EventId("\$a:b"),
     listData = listData.toPersistentList(),
     currentIndex = currentIndex,
     snackbarMessage = null,

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerView.kt

@@ -142,8 +142,13 @@ fun MediaViewerView(
                     Box(
                         modifier = Modifier.fillMaxSize()
                     ) {
+                        val isDisplayed = remember(pagerState.settledPage) {
+                            // This 'item provider' lambda will be called when the data source changes with an outdated `settlePage` value
+                            // So we need to update this value only when the `settledPage` value changes. It seems like a bug that needs to be fixed in Compose.
+                            page == pagerState.settledPage
+                        }
                         MediaViewerPage(
-                            isDisplayed = page == pagerState.settledPage,
+                            isDisplayed = isDisplayed,
                             showOverlay = showOverlay,
                             bottomPaddingInPixels = bottomPaddingInPixels,
                             data = dataForPage,
@@ -157,7 +162,8 @@ fun MediaViewerView(
                             },
                             onShowOverlayChange = {
                                 showOverlay = it
-                            }
+                            },
+                            isUserSelected = (state.listData[page] as? MediaViewerPageData.MediaViewerData)?.eventId == state.initiallySelectedEventId,
                         )
                         // Bottom bar
                         AnimatedVisibility(visible = showOverlay, enter = fadeIn(), exit = fadeOut()) {
@@ -273,6 +279,7 @@ private fun MediaViewerPage(
     bottomPaddingInPixels: Int,
     data: MediaViewerPageData.MediaViewerData,
     textFileViewer: TextFileViewer,
+    isUserSelected: Boolean,
     onDismiss: () -> Unit,
     onRetry: () -> Unit,
     onDismissError: () -> Unit,
@@ -328,6 +335,7 @@ private fun MediaViewerPage(
                             currentOnShowOverlayChange(!currentShowOverlay)
                         }
                     },
+                    isUserSelected = isUserSelected,
                 )
                 ThumbnailView(
                     mediaInfo = data.mediaInfo,