feat(lyrics): keep the screen awake while viewing lyrics

test/lyrics_screen_awake_test.dart

@@ -0,0 +1,132 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:spotiflac_android/models/settings.dart';
+import 'package:spotiflac_android/providers/settings_provider.dart';
+import 'package:spotiflac_android/widgets/lyrics_screen_awake.dart';
+
+class _Settings extends SettingsNotifier {
+  @override
+  AppSettings build() => const AppSettings();
+
+  @override
+  void setKeepScreenOnLyrics(bool enabled) {
+    state = state.copyWith(keepScreenOnLyrics: enabled);
+  }
+}
+
+void main() {
+  final binding = TestWidgetsFlutterBinding.ensureInitialized();
+  const channel = MethodChannel('com.zarz.spotiflac/backend');
+  late List<bool> requests;
+
+  setUp(() {
+    requests = [];
+    binding.defaultBinaryMessenger.setMockMethodCallHandler(channel, (
+      call,
+    ) async {
+      if (call.method == 'setScreenAwake') {
+        requests.add(
+          (call.arguments as Map<Object?, Object?>)['enabled']! as bool,
+        );
+      }
+      return null;
+    });
+    binding.handleAppLifecycleStateChanged(AppLifecycleState.resumed);
+  });
+
+  tearDown(() {
+    binding.defaultBinaryMessenger.setMockMethodCallHandler(channel, null);
+  });
+
+  test('screen preference defaults on and survives settings round trips', () {
+    expect(AppSettings.fromJson({}).keepScreenOnLyrics, isTrue);
+    for (final enabled in [false, true]) {
+      final settings = const AppSettings().copyWith(
+        keepScreenOnLyrics: enabled,
+      );
+      expect(
+        AppSettings.fromJson(settings.toJson()).keepScreenOnLyrics,
+        enabled,
+      );
+    }
+  });
+
+  testWidgets('only visible lyrics hold the screen awake and release on exit', (
+    tester,
+  ) async {
+    final visible = ValueNotifier(false);
+    addTearDown(visible.dispose);
+    await tester.pumpWidget(
+      ProviderScope(
+        overrides: [settingsProvider.overrideWith(_Settings.new)],
+        child: MaterialApp(
+          home: ValueListenableBuilder(
+            valueListenable: visible,
+            builder: (context, value, _) =>
+                LyricsScreenAwake(visible: value, child: const SizedBox()),
+          ),
+        ),
+      ),
+    );
+    expect(requests, isEmpty);
+    visible.value = true;
+    await tester.pump();
+    expect(requests, [true]);
+    await tester.pump();
+    expect(requests, [
+      true,
+    ], reason: 'No repeated requests on unchanged frames');
+    visible.value = false;
+    await tester.pump();
+    expect(requests, [true, false]);
+    visible.value = true;
+    await tester.pump();
+    await tester.pumpWidget(const SizedBox());
+    expect(requests, [true, false, true, false]);
+  });
+
+  testWidgets(
+    'releases in background, under another route, and when disabled',
+    (tester) async {
+      final navigator = GlobalKey<NavigatorState>();
+      final container = ProviderContainer(
+        overrides: [settingsProvider.overrideWith(_Settings.new)],
+      );
+      addTearDown(container.dispose);
+      await tester.pumpWidget(
+        UncontrolledProviderScope(
+          container: container,
+          child: MaterialApp(
+            navigatorKey: navigator,
+            home: const LyricsScreenAwake(visible: true, child: SizedBox()),
+          ),
+        ),
+      );
+      expect(requests.last, isTrue);
+      binding.handleAppLifecycleStateChanged(AppLifecycleState.inactive);
+      await tester.pump();
+      expect(requests.last, isFalse);
+      binding.handleAppLifecycleStateChanged(AppLifecycleState.paused);
+      binding.handleAppLifecycleStateChanged(AppLifecycleState.resumed);
+      await tester.pump();
+      expect(requests.last, isTrue);
+      navigator.currentState!.push<void>(
+        MaterialPageRoute(builder: (_) => const Scaffold()),
+      );
+      await tester.pumpAndSettle();
+      expect(requests.last, isFalse);
+      navigator.currentState!.pop();
+      await tester.pumpAndSettle();
+      expect(requests.last, isTrue);
+      container.read(settingsProvider.notifier).setKeepScreenOnLyrics(false);
+      await tester.pump();
+      expect(requests.last, isFalse);
+      binding.handleAppLifecycleStateChanged(AppLifecycleState.inactive);
+      binding.handleAppLifecycleStateChanged(AppLifecycleState.resumed);
+      await tester.pump();
+      expect(requests.last, isFalse);
+    },
+  );
+}

test/now_playing_lyrics_transition_test.dart

@@ -63,6 +63,7 @@ void main() {
         .setMockMethodCallHandler(secureStorageChannel, (_) async => null);
     TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
         .setMockMethodCallHandler(backendChannel, (call) async {
+          if (call.method == 'setScreenAwake') return null;
           if (call.method != 'readFileMetadata') {
             fail('Unexpected platform call: ${call.method}');
           }