import 'package:flutter/material.dart';

import 'core/app_state.dart';
import 'core/app_theme.dart';
import 'core/courses/course_repository.dart';
import 'core/sync/sync_coordinator.dart';
import 'core/sherpa_stt_service.dart';
import 'features/onboarding/onboarding_pages.dart';
import 'features/shell/learning_shell.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  // A0 is the offline baseline; the later levels load with the app state.
  await CourseRepository.instance.load(levels: {'A0'});
  runApp(const KouyuEnglishApp());
}

class KouyuEnglishApp extends StatefulWidget {
  const KouyuEnglishApp({super.key});

  @override
  State<KouyuEnglishApp> createState() => _KouyuEnglishAppState();
}

class _KouyuEnglishAppState extends State<KouyuEnglishApp> {
  final appState = AppState();
  var onboardingStep = 0;

  @override
  void initState() {
    super.initState();
    // 异步静默预热打包在本地的 SenseVoice 离线语音模型，加速首次语音交互
    SherpaSttService.instance.initialize().then((ok) {
      debugPrint('[Main] 离线 SenseVoice 语音引擎预热状态: $ok');
    });
    SyncCoordinator.instance.init().then((_) {
      if (mounted && appState.isLoaded) {
        SyncCoordinator.instance.triggerBackgroundSync(appState);
      }
    });
    appState.load().then((_) {
      if (mounted && SyncCoordinator.instance.isInitialized) {
        SyncCoordinator.instance.triggerBackgroundSync(appState);
      }
    });
  }

  @override
  void dispose() {
    appState.dispose();
    super.dispose();
  }

  static ThemeMode _themeMode(AppThemeMode mode) => switch (mode) {
    AppThemeMode.system => ThemeMode.system,
    AppThemeMode.light => ThemeMode.light,
    AppThemeMode.dark => ThemeMode.dark,
  };

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: appState,
      builder: (context, _) => MaterialApp(
        title: '芽说英语 · SpeakSprout',
        debugShowCheckedModeBanner: false,
        theme: buildAppTheme(Brightness.light),
        darkTheme: buildAppTheme(Brightness.dark),
        themeMode: _themeMode(appState.themeMode),
        // Mirror the resolved brightness into the global palette that many
        // widgets read directly, so it tracks both the user's choice and any
        // system dark-mode change.
        builder: (context, child) {
          AppColors.applyBrightness(Theme.of(context).brightness);
          return child ?? const SizedBox.shrink();
        },
        home: Builder(
          builder: (context) {
            if (!appState.isLoaded) {
              return const Scaffold(
                body: Center(child: CircularProgressIndicator()),
              );
            }
            if (appState.onboardingComplete) {
              return LearningShell(state: appState);
            }
            if (onboardingStep == 0) {
              return WelcomePage(
                state: appState,
                onContinue: () => setState(() => onboardingStep = 1),
              );
            }
            return PopScope(
              canPop: false,
              onPopInvokedWithResult: (didPop, _) {
                if (!didPop) {
                  setState(() => onboardingStep = 0);
                }
              },
              child: PlacementPage(
                state: appState,
                onBack: () => setState(() => onboardingStep = 0),
                onStart: () => appState.finishOnboarding(),
              ),
            );
          },
        ),
      ),
    );
  }
}