perf(ui): pause motion headers when collapsed

test/motion_header_banner_test.dart

@@ -0,0 +1,122 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:spotiflac_android/widgets/motion_header_banner.dart';
+import 'package:video_player_platform_interface/video_player_platform_interface.dart';
+
+class _VideoPlatform extends VideoPlayerPlatform {
+  bool playing = false;
+  int playCalls = 0;
+
+  @override
+  Future<void> init() async {}
+
+  @override
+  Future<int?> createWithOptions(VideoCreationOptions options) async => 1;
+
+  @override
+  Stream<VideoEvent> videoEventsFor(int playerId) => Stream.value(
+    VideoEvent(
+      eventType: VideoEventType.initialized,
+      duration: const Duration(seconds: 30),
+      size: const Size(320, 180),
+    ),
+  );
+
+  @override
+  Future<void> play(int playerId) async {
+    playing = true;
+    playCalls++;
+  }
+
+  @override
+  Future<void> pause(int playerId) async => playing = false;
+
+  @override
+  Future<void> setLooping(int playerId, bool looping) async {}
+
+  @override
+  Future<void> setVolume(int playerId, double volume) async {}
+
+  @override
+  Future<void> setPlaybackSpeed(int playerId, double speed) async {}
+
+  @override
+  Future<void> setMixWithOthers(bool mixWithOthers) async {}
+
+  @override
+  Future<Duration> getPosition(int playerId) async => Duration.zero;
+
+  @override
+  Widget buildViewWithOptions(VideoViewOptions options) => const SizedBox();
+
+  @override
+  Future<void> dispose(int playerId) async {}
+}
+
+void main() {
+  testWidgets('collapsed headers pause video and visible headers resume', (
+    tester,
+  ) async {
+    final previousPlatform = VideoPlayerPlatform.instance;
+    final platform = _VideoPlatform();
+    VideoPlayerPlatform.instance = platform;
+    addTearDown(() => VideoPlayerPlatform.instance = previousPlatform);
+    final scroll = ScrollController();
+    addTearDown(scroll.dispose);
+
+    Widget app({bool active = true}) => MaterialApp(
+      home: Scaffold(
+        body: TickerMode(
+          enabled: active,
+          child: CustomScrollView(
+            controller: scroll,
+            slivers: const [
+              SliverAppBar(
+                pinned: true,
+                expandedHeight: 300,
+                flexibleSpace: FlexibleSpaceBar(
+                  background: MotionHeaderBanner(
+                    videoUrl: 'https://example.com/banner.m3u8',
+                    fallback: ColoredBox(color: Colors.blue),
+                  ),
+                ),
+              ),
+              SliverToBoxAdapter(child: SizedBox(height: 2000)),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    await tester.pumpWidget(app());
+    await tester.pump();
+    expect(platform.playing, isTrue);
+    final initialPlayCalls = platform.playCalls;
+
+    scroll.jumpTo(50);
+    await tester.pump();
+    expect(platform.playCalls, initialPlayCalls);
+    scroll.jumpTo(400);
+    await tester.pump();
+    expect(platform.playing, isFalse);
+
+    scroll.jumpTo(0);
+    await tester.pump();
+    expect(platform.playing, isTrue);
+    await tester.pumpWidget(app(active: false));
+    await tester.pump();
+    expect(platform.playing, isFalse);
+    await tester.pumpWidget(app());
+    await tester.pump();
+    expect(platform.playing, isTrue);
+
+    tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.paused);
+    await tester.pump();
+    expect(platform.playing, isFalse);
+    tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.resumed);
+    await tester.pump();
+    expect(platform.playing, isTrue);
+    await tester.pumpWidget(const SizedBox());
+    await tester.pump();
+  });
+}