import 'dart:async';
import 'package:app_links/app_links.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'providers/auth_provider.dart';
import 'providers/accounts_provider.dart';
import 'providers/categories_provider.dart';
import 'providers/merchants_provider.dart';
import 'providers/tags_provider.dart';
import 'providers/transactions_provider.dart';
import 'providers/chat_provider.dart';
import 'providers/theme_provider.dart';
import 'providers/privacy_provider.dart';
import 'screens/backend_config_screen.dart';
import 'screens/login_screen.dart';
import 'screens/biometric_lock_screen.dart';
import 'screens/main_navigation_screen.dart';
import 'screens/sso_onboarding_screen.dart';
import 'services/api_config.dart';
import 'services/connectivity_service.dart';
import 'services/log_service.dart';
import 'services/preferences_service.dart';
import 'services/telemetry_service.dart';
import 'theme/sure_theme.dart';
import 'l10n/app_localizations.dart';
import 'package:upgrader/upgrader.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await ApiConfig.initialize();

  // Add initial log entry
  LogService.instance.info('App', 'Sure app starting...');

  // Read the privacy preference before the first frame so money values are
  // never briefly rendered unmasked for a user who enabled "Hide amounts".
  // Default to masked (fail-closed) if it can't be read.
  bool moneyHidden = true;
  try {
    moneyHidden = await PreferencesService.instance.getMoneyHidden();
  } catch (e) {
    LogService.instance.warning(
      'App',
      'Failed to read privacy preference at startup with ${e.runtimeType}',
    );
  }

  await TelemetryService.instance.initialize(
    appRunner: () => runApp(SureApp(moneyHidden: moneyHidden)),
  );
}

class SureApp extends StatelessWidget {
  // Fail-closed default (masked) for the no-argument path; main() always passes
  // the persisted value explicitly.
  const SureApp({super.key, this.moneyHidden = true});

  /// The persisted "hide amounts" state, read before `runApp` (see `main`).
  final bool moneyHidden;

  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => LogService.instance),
        ChangeNotifierProvider(create: (_) => ConnectivityService()),
        ChangeNotifierProvider(create: (_) => AuthProvider()),
        ChangeNotifierProvider(create: (_) => ChatProvider()),
        ChangeNotifierProvider(create: (_) => CategoriesProvider()),
        ChangeNotifierProvider(create: (_) => MerchantsProvider()),
        ChangeNotifierProvider(create: (_) => TagsProvider()),
        ChangeNotifierProvider(create: (_) => ThemeProvider()),
        ChangeNotifierProvider(
            create: (_) => PrivacyProvider(initialHidden: moneyHidden)),
        ChangeNotifierProxyProvider<ConnectivityService, AccountsProvider>(
          create: (_) => AccountsProvider(),
          update: (_, connectivityService, accountsProvider) {
            if (accountsProvider == null) {
              final provider = AccountsProvider();
              provider.setConnectivityService(connectivityService);
              return provider;
            } else {
              accountsProvider.setConnectivityService(connectivityService);
              return accountsProvider;
            }
          },
        ),
        ChangeNotifierProxyProvider<ConnectivityService, TransactionsProvider>(
          create: (_) => TransactionsProvider(),
          update: (_, connectivityService, transactionsProvider) {
            if (transactionsProvider == null) {
              final provider = TransactionsProvider();
              provider.setConnectivityService(connectivityService);
              return provider;
            } else {
              transactionsProvider.setConnectivityService(connectivityService);
              return transactionsProvider;
            }
          },
        ),
      ],
      child: Consumer<ThemeProvider>(
        builder: (context, themeProvider, _) => MaterialApp(
          onGenerateTitle: (ctx) => AppLocalizations.of(ctx).appTitle,
          localizationsDelegates: AppLocalizations.localizationsDelegates,
          supportedLocales: AppLocalizations.supportedLocales,
          debugShowCheckedModeBanner: false,
          navigatorObservers: TelemetryService.instance.navigatorObservers,
          theme: SureTheme.light,
          darkTheme: SureTheme.dark,
          themeMode: themeProvider.themeMode,
          routes: {
            '/config': (context) => const BackendConfigScreen(),
            '/login': (context) => const LoginScreen(),
            '/home': (context) => const MainNavigationScreen(),
          },
          home: const AppWrapper(),
        ),
      ),
    );
  }
}

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

  @override
  State<AppWrapper> createState() => _AppWrapperState();
}

class _AppWrapperState extends State<AppWrapper> with WidgetsBindingObserver {
  bool _isCheckingConfig = true;
  bool _hasBackendUrl = false;
  bool _isLocked = false;
  late final AppLinks _appLinks;
  StreamSubscription<Uri>? _linkSubscription;

  final _upgrader = Upgrader(
    durationUntilAlertAgain: const Duration(days: 7),
    countryCode: 'us',
    messages: _SureUpgraderMessages(),
  );

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _checkBackendConfig();
    _initDeepLinks();
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _linkSubscription?.cancel();
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.paused) {
      _markLockedIfEnabled();
    } else if (state == AppLifecycleState.resumed && _isLocked) {
      // Lock screen is already showing via build(); biometric auto-triggers there.
    }
  }

  Future<void> _markLockedIfEnabled() async {
    final authProvider = Provider.of<AuthProvider>(context, listen: false);
    if (!authProvider.isAuthenticated) return;
    final enabled = await PreferencesService.instance.getBiometricEnabled();
    if (enabled && mounted) {
      setState(() => _isLocked = true);
    }
  }

  void _onUnlocked() {
    if (mounted) setState(() => _isLocked = false);
  }

  Future<void> _onLockLogout() async {
    final authProvider = Provider.of<AuthProvider>(context, listen: false);
    await authProvider.logout();
    if (mounted) setState(() => _isLocked = false);
  }

  void _initDeepLinks() {
    _appLinks = AppLinks();

    // Handle deep link that launched the app (cold start)
    _appLinks.getInitialLink().then((uri) {
      if (uri != null) {
        TelemetryService.instance.addBreadcrumb(
          'deep_links',
          'initial_link_received',
          data: {'recognized': _isSsoCallback(uri)},
        );
        _handleDeepLink(uri);
      }
    }).catchError((e, stackTrace) {
      LogService.instance.error(
        'DeepLinks',
        'Initial link failed with ${e.runtimeType}',
      );
      unawaited(TelemetryService.instance.captureHandledException(
        e,
        stackTrace,
        operation: 'deep_links.initial_link',
      ));
    });

    // Listen for deep links while app is running
    _linkSubscription = _appLinks.uriLinkStream.listen(
      (uri) => _handleDeepLink(uri),
      onError: (e, stackTrace) {
        LogService.instance.error(
          'DeepLinks',
          'Link stream failed with ${e.runtimeType}',
        );
        unawaited(TelemetryService.instance.captureHandledException(
          e,
          stackTrace,
          operation: 'deep_links.stream',
        ));
      },
    );
  }

  void _handleDeepLink(Uri uri) {
    final isSsoCallback = _isSsoCallback(uri);
    TelemetryService.instance.addBreadcrumb(
      'deep_links',
      'link_received',
      data: {'recognized': isSsoCallback},
    );

    if (isSsoCallback) {
      final authProvider = Provider.of<AuthProvider>(context, listen: false);
      authProvider.handleSsoCallback(uri);
    }
  }

  bool _isSsoCallback(Uri uri) =>
      uri.scheme == 'sureapp' && uri.host == 'oauth';

  Future<void> _checkBackendConfig() async {
    final hasUrl = await TelemetryService.instance.traceAsync(
      'app.backend_config_check',
      'Backend configuration check',
      ApiConfig.initialize,
    );
    TelemetryService.instance.addBreadcrumb(
      'app',
      'backend_config_checked',
      data: {'configured': hasUrl},
    );
    if (mounted) {
      setState(() {
        _hasBackendUrl = hasUrl;
        _isCheckingConfig = false;
      });
    }
  }

  void _onBackendConfigSaved() {
    setState(() {
      _hasBackendUrl = true;
    });
  }

  @override
  Widget build(BuildContext context) {
    if (_isCheckingConfig) {
      return const Scaffold(
        body: Center(
          child: CircularProgressIndicator(),
        ),
      );
    }

    if (!_hasBackendUrl) {
      return BackendConfigScreen(
        onConfigSaved: _onBackendConfigSaved,
      );
    }

    return Consumer<AuthProvider>(
      builder: (context, authProvider, _) {
        // Only show loading spinner during initial auth check
        if (authProvider.isInitializing) {
          return const Scaffold(
            body: Center(
              child: CircularProgressIndicator(),
            ),
          );
        }

        if (authProvider.isAuthenticated) {
          return Stack(
            children: [
              UpgradeAlert(
                upgrader: _upgrader,
                showIgnore: false,
                child: const MainNavigationScreen(),
              ),
              if (_isLocked)
                BiometricLockScreen(
                  onUnlocked: _onUnlocked,
                  onLogout: _onLockLogout,
                ),
            ],
          );
        }

        // Clear stale lock state so it doesn't flash on the next login.
        if (_isLocked) {
          WidgetsBinding.instance.addPostFrameCallback((_) {
            if (mounted) setState(() => _isLocked = false);
          });
        }

        if (authProvider.ssoOnboardingPending) {
          return const SsoOnboardingScreen();
        }

        return const LoginScreen();
      },
    );
  }
}

class _SureUpgraderMessages extends UpgraderMessages {
  @override
  String get title => 'Update available';

  @override
  String get body =>
      '{{appName}} {{currentAppStoreVersion}} is now available — '
      'you have {{currentInstalledVersion}}.\n\n'
      "What's new? Check the store for release notes.";

  @override
  String get buttonTitleUpdate => 'Update now';

  @override
  String get buttonTitleLater => 'Later';

  @override
  String get releaseNotes => '';
}