import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

import '../core/auth/session_store.dart';
import '../data/network/api_client.dart';
import '../data/storage/local_kv_store.dart';
import '../features/auth/data/apis/auth_api.dart';
import '../features/auth/data/repositories/auth_repository.dart';
import '../features/auth/presentation/bloc/auth_bloc.dart';
import '../features/auth/presentation/bloc/auth_state.dart';
import '../features/auth/presentation/screens/login_screen.dart';
import '../features/divination/data/apis/divination_api.dart';
import '../features/home/presentation/screens/home_screen.dart';
import '../features/settings/data/models/profile_settings.dart';
import '../l10n/app_localizations.dart';
import '../shared/widgets/app_loading_indicator.dart';
import 'app_theme.dart';
import 'di/injection.dart';

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

  @override
  State<EryaoApp> createState() => _EryaoAppState();
}

class _EryaoAppState extends State<EryaoApp> {
  final SessionStore _sessionStore = SessionStore(LocalKvStore());
  late final AuthBloc _authBloc;
  late final DivinationApi _divinationApi;
  Locale _locale = const Locale('zh');
  ProfileSettingsV1 _profileSettings = ProfileSettingsV1.defaultsForLocale(
    const Locale('zh'),
  );
  int _creditsBalance = 0;
  bool _loadingCredits = false;
  String? _loadedCreditsUserEmail;

  @override
  void initState() {
    super.initState();
    final apiClient = ApiClient(
      baseUrl: appDependencies.backendUrl,
      tokenProvider: _sessionStore.getToken,
      onUnauthorized: () {
        return _authBloc.handleUnauthorized401();
      },
    );
    final authApi = AuthApi(apiClient: apiClient);
    _divinationApi = DivinationApi(apiClient: apiClient);
    final authRepository = AuthRepositoryImpl(
      authApi: authApi,
      sessionStore: _sessionStore,
    );
    _authBloc = AuthBloc(repository: authRepository);
    _bootstrap();
  }

  void _ensureCreditsLoaded(String userEmail) {
    if (_loadingCredits) {
      return;
    }
    if (_loadedCreditsUserEmail == userEmail) {
      return;
    }
    _loadingCredits = true;
    _divinationApi
        .getPointsBalance()
        .then((balance) {
          if (!mounted) {
            return;
          }
          setState(() {
            _creditsBalance = balance.availableBalance;
            _loadedCreditsUserEmail = userEmail;
          });
        })
        .whenComplete(() {
          _loadingCredits = false;
        });
  }

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

  Future<void> _bootstrap() async {
    final localeCode = await _sessionStore.getLocaleCode();
    final locale = localeCode == 'en' ? const Locale('en') : const Locale('zh');
    if (mounted) {
      setState(() {
        _locale = locale;
        _profileSettings = ProfileSettingsV1.defaultsForLocale(locale);
      });
    }
    await _authBloc.start();
  }

  Future<void> _handleInterfaceLanguageChanged(String languageTag) async {
    final locale = localeFromLanguageTag(languageTag);
    await _sessionStore.saveLocaleCode(locale.languageCode);
    if (!mounted) {
      return;
    }
    setState(() {
      _locale = locale;
      _profileSettings = _profileSettings.copyWith(
        preferences: _profileSettings.preferences.copyWith(
          interfaceLanguage: languageTag,
        ),
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _authBloc,
      builder: (context, _) {
        return MaterialApp(
          debugShowCheckedModeBanner: false,
          onGenerateTitle: (context) => AppLocalizations.of(context)!.appTitle,
          locale: _locale,
          localizationsDelegates: const [
            AppLocalizations.delegate,
            GlobalMaterialLocalizations.delegate,
            GlobalWidgetsLocalizations.delegate,
            GlobalCupertinoLocalizations.delegate,
          ],
          supportedLocales: AppLocalizations.supportedLocales,
          theme: AppTheme.light(),
          home: _buildHomeByAuthState(_authBloc.state),
        );
      },
    );
  }

  Widget _buildHomeByAuthState(AuthState state) {
    if (state.status == AuthStatus.initial ||
        state.status == AuthStatus.loading) {
      return const Scaffold(
        body: Center(
          child: AppLoadingIndicator(variant: AppLoadingVariant.surface),
        ),
      );
    }

    if (state.status == AuthStatus.authenticated && state.user != null) {
      _ensureCreditsLoaded(state.user!.email);
      return HomeScreen(
        account: state.user!.email,
        sessionStore: _sessionStore,
        currentLocale: _locale,
        profileSettings: _profileSettings,
        coinBalance: _creditsBalance,
        onLocaleChanged: _handleInterfaceLanguageChanged,
        onLogout: _authBloc.logout,
      );
    }

    return LoginScreen(
      currentLocale: _locale,
      onLocaleChanged: (_) {},
      onRequestOtp: _authBloc.sendOtp,
      onLoginWithOtp: (email, otp) {
        return _authBloc.loginWithOtp(email: email, otp: otp);
      },
    );
  }
}