feat(mobile): consolidate video controls (#26673)

Videos have recently been changed to support zooming, but this can make
the controls in the centre of the screen unergonomic as they will either
stay in the centre when dismissing, or stick to the video when zooming.
Neither is great. We should align the behaviour with other apps which
has the play/pause toggle at the bottom of the screen with the seeker
bar instead.

Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/lib/providers/asset_viewer/asset_viewer.provider.dart

@@ -100,11 +100,11 @@ class AssetViewerStateNotifier extends Notifier<AssetViewerState> {
       return;
     }
     state = state.copyWith(showingDetails: showing, showingControls: showing ? true : state.showingControls);
-    if (showing) {
-      final heroTag = state.currentAsset?.heroTag;
-      if (heroTag != null) {
-        ref.read(videoPlayerProvider(heroTag).notifier).pause();
-      }
+
+    final heroTag = state.currentAsset?.heroTag;
+    if (heroTag != null) {
+      final notifier = ref.read(videoPlayerProvider(heroTag).notifier);
+      showing ? notifier.hold() : notifier.release();
     }
   }
 

mobile/lib/providers/asset_viewer/video_player_provider.dart

@@ -44,10 +44,7 @@ class VideoPlayerNotifier extends StateNotifier<VideoPlayerState> {
   NativeVideoPlayerController? _controller;
   Timer? _bufferingTimer;
   Timer? _seekTimer;
-
-  void attachController(NativeVideoPlayerController controller) {
-    _controller = controller;
-  }
+  VideoPlaybackStatus? _holdStatus;
 
   @override
   void dispose() {
@@ -59,6 +56,19 @@ class VideoPlayerNotifier extends StateNotifier<VideoPlayerState> {
     super.dispose();
   }
 
+  void attachController(NativeVideoPlayerController controller) {
+    _controller = controller;
+  }
+
+  Future<void> load(VideoSource source) async {
+    _startBufferingTimer();
+    try {
+      await _controller?.loadVideoSource(source);
+    } catch (e) {
+      _log.severe('Error loading video source: $e');
+    }
+  }
+
   Future<void> pause() async {
     if (_controller == null) return;
 
@@ -94,16 +104,50 @@ class VideoPlayerNotifier extends StateNotifier<VideoPlayerState> {
   }
 
   void seekTo(Duration position) {
-    if (_controller == null) return;
+    if (_controller == null || state.position == position) return;
 
     state = state.copyWith(position: position);
 
-    _seekTimer?.cancel();
-    _seekTimer = Timer(const Duration(milliseconds: 100), () {
-      _controller?.seekTo(position.inMilliseconds);
+    if (_seekTimer?.isActive ?? false) return;
+
+    _seekTimer = Timer(const Duration(milliseconds: 150), () {
+      _controller?.seekTo(state.position.inMilliseconds);
     });
   }
 
+  void toggle() {
+    _holdStatus = null;
+
+    switch (state.status) {
+      case VideoPlaybackStatus.paused:
+        play();
+      case VideoPlaybackStatus.playing || VideoPlaybackStatus.buffering:
+        pause();
+      case VideoPlaybackStatus.completed:
+        restart();
+    }
+  }
+
+  /// Pauses playback and preserves the current status for later restoration.
+  void hold() {
+    if (_holdStatus != null) return;
+
+    _holdStatus = state.status;
+    pause();
+  }
+
+  /// Restores playback to the status before [hold] was called.
+  void release() {
+    final status = _holdStatus;
+    _holdStatus = null;
+
+    switch (status) {
+      case VideoPlaybackStatus.playing || VideoPlaybackStatus.buffering:
+        play();
+      default:
+    }
+  }
+
   Future<void> restart() async {
     seekTo(Duration.zero);
     await play();
@@ -149,13 +193,12 @@ class VideoPlayerNotifier extends StateNotifier<VideoPlayerState> {
     final position = Duration(milliseconds: playbackInfo.position);
     if (state.position == position) return;
 
-    if (state.status == VideoPlaybackStatus.buffering) {
-      state = state.copyWith(position: position, status: VideoPlaybackStatus.playing);
-    } else {
-      state = state.copyWith(position: position);
-    }
+    if (state.status == VideoPlaybackStatus.playing) _startBufferingTimer();
 
-    _startBufferingTimer();
+    state = state.copyWith(
+      position: position,
+      status: state.status == VideoPlaybackStatus.buffering ? VideoPlaybackStatus.playing : null,
+    );
   }
 
   void onNativeStatusChanged() {
@@ -173,9 +216,7 @@ class VideoPlayerNotifier extends StateNotifier<VideoPlayerState> {
         onNativePlaybackEnded();
     }
 
-    if (state.status != newStatus) {
-      state = state.copyWith(status: newStatus);
-    }
+    if (state.status != newStatus) state = state.copyWith(status: newStatus);
   }
 
   void onNativePlaybackEnded() {
@@ -186,7 +227,7 @@ class VideoPlayerNotifier extends StateNotifier<VideoPlayerState> {
   void _startBufferingTimer() {
     _bufferingTimer?.cancel();
     _bufferingTimer = Timer(const Duration(seconds: 3), () {
-      if (mounted && state.status == VideoPlaybackStatus.playing) {
+      if (mounted && state.status != VideoPlaybackStatus.completed) {
         state = state.copyWith(status: VideoPlaybackStatus.buffering);
       }
     });

mobile/lib/providers/cast.provider.dart

@@ -91,6 +91,16 @@ class CastNotifier extends StateNotifier<CastManagerState> {
     return discovered;
   }
 
+  void toggle() {
+    switch (state.castState) {
+      case CastState.playing:
+        pause();
+      case CastState.paused:
+        play();
+      default:
+    }
+  }
+
   void play() {
     _gCastService.play();
   }