import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:easy_localization/easy_localization.dart' hide tr;
import 'package:go_router/go_router.dart';
import 'package:flutter/services.dart';
import 'package:flutter_web_plugins/url_strategy.dart';
import 'features/auth/presentation/login_screen.dart';
import 'features/auth/presentation/signup_screen.dart';
import 'features/auth/presentation/approve_qr_screen.dart';
import 'features/auth/presentation/qr_scan_screen.dart';
import 'features/auth/presentation/forgot_password_screen.dart';
import 'features/auth/presentation/reset_password_screen.dart';
import 'features/auth/presentation/error_screen.dart';
import 'features/dashboard/presentation/dashboard_screen.dart';
import 'features/admin/presentation/user_management_screen.dart';
import 'features/profile/presentation/pages/profile_page.dart';
import 'core/services/auth_proxy_service.dart';
import 'core/services/auth_token_store.dart';
import 'core/services/logger_service.dart';
import 'core/notifiers/auth_notifier.dart';
import 'core/i18n/locale_gate.dart';
import 'core/i18n/locale_registry.dart';
import 'core/i18n/locale_utils.dart';
import 'core/i18n/toml_asset_loader.dart';
import 'package:logging/logging.dart';
import 'features/auth/presentation/consent_screen.dart';
import 'i18n.dart';

final _log = Logger('Main');

Future<void> _loadBundledFonts() async {
  const family = 'NotoSansKR';
  final loader = FontLoader(family);
  try {
    loader.addFont(rootBundle.load('assets/fonts/NotoSansKR-Regular.ttf'));
    loader.addFont(rootBundle.load('assets/fonts/NotoSansKR-Bold.ttf'));
    await loader.load();
  } catch (e) {
    _log.warning("Failed to preload bundled fonts: $e");
  }
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  usePathUrlStrategy();
  await EasyLocalization.ensureInitialized();
  await LocaleRegistry.initialize();

  // 1. Global Error Handling
  FlutterError.onError = (details) {
    FlutterError.presentError(details);
    _log.severe("FLUTTER_ERROR", details.exception, details.stack);
    // Also send to backend if needed
    AuthProxyService.logError(
      "FLUTTER_ERROR: ${details.exception}\n${details.stack}",
    );
  };

  PlatformDispatcher.instance.onError = (error, stack) {
    _log.severe("PLATFORM_ERROR", error, stack);
    AuthProxyService.logError("PLATFORM_ERROR: $error\n$stack");
    return true;
  };

  // .env가 없더라도 초기화 상태를 보장하도록 optional 로딩
  try {
    await dotenv.load(fileName: ".env", isOptional: true);
  } catch (e) {
    _log.warning("Warning: .env file load failed: $e");
  }

  // 0. Initialize Logger
  LoggerService.init();

  // 폰트를 먼저 로딩해서 렌더링 깨짐(FOIT/FOUT) 최소화
  await _loadBundledFonts();

  runApp(
    // URL(/en, /ko)이 있으면 우선 적용해서 첫 렌더부터 올바른 언어로 시작합니다.
    () {
      final supportedLocaleCodes = LocaleRegistry.supportedLocaleCodes;
      final supportedLocales = supportedLocaleCodes
          .map((code) => Locale(code))
          .toList(growable: false);
      final fallbackLocaleCode = LocaleRegistry.fallbackLocaleCode;
      final initialLocaleCode =
          extractLocaleFromPath(Uri.base) ?? resolvePreferredLocaleCode();
      return EasyLocalization(
        supportedLocales: supportedLocales,
        fallbackLocale: Locale(fallbackLocaleCode),
        startLocale: Locale(initialLocaleCode),
        saveLocale: false,
        path: 'assets/translations',
        assetLoader: const TomlAssetLoader(),
        child: const ProviderScope(child: BaronSSOApp()),
      );
    }(),
  );
}

// Router Configuration
final _routerLogger = Logger('Router');

final _router = GoRouter(
  initialLocation: '/',
  debugLogDiagnostics: !kReleaseMode,
  refreshListenable: AuthNotifier.instance,
  routes: [
    ShellRoute(
      builder: (context, state, child) {
        final localeCode =
            extractLocaleFromPath(state.uri) ?? resolvePreferredLocaleCode();
        return LocaleGate(localeCode: localeCode, child: child);
      },
      routes: [
        GoRoute(
          path: '/:locale',
          builder: (context, state) {
            _routerLogger.info("Navigating to root (DashboardScreen)");
            return const DashboardScreen();
          },
          routes: [
            GoRoute(
              path: 'profile',
              builder: (context, state) => const ProfilePage(),
            ),
            GoRoute(
              path: 'signin',
              builder: (context, state) {
                final loginChallenge =
                    state.uri.queryParameters['login_challenge'];
                final redirectUrl =
                    state.uri.queryParameters['redirect_uri'] ??
                    state.uri.queryParameters['redirect_url'];
                _routerLogger.info(
                  "Navigating to /signin with login_challenge: $loginChallenge, redirect: $redirectUrl",
                );
                return LoginScreen(
                  key: state.pageKey,
                  loginChallenge: loginChallenge,
                  redirectUrl: redirectUrl,
                );
              },
            ),
            GoRoute(
              path: 'login',
              builder: (context, state) {
                final loginChallenge =
                    state.uri.queryParameters['login_challenge'];
                final redirectUrl =
                    state.uri.queryParameters['redirect_uri'] ??
                    state.uri.queryParameters['redirect_url'];
                _routerLogger.info(
                  "Navigating to /login with login_challenge: $loginChallenge, redirect: $redirectUrl",
                );
                return LoginScreen(
                  key: state.pageKey,
                  loginChallenge: loginChallenge,
                  redirectUrl: redirectUrl,
                );
              },
            ),
            GoRoute(
              path: 'consent',
              builder: (BuildContext context, GoRouterState state) {
                final consentChallenge =
                    state.uri.queryParameters['consent_challenge'];
                if (consentChallenge == null) {
                  _routerLogger.warning(
                    "Consent screen loaded without a challenge.",
                  );
                  return const Scaffold(
                    body: Center(
                      child: Text('Error: Consent challenge is missing.'),
                    ),
                  );
                }
                _routerLogger.info("Navigating to /consent with challenge.");
                return ConsentScreen(consentChallenge: consentChallenge);
              },
            ),
            GoRoute(
              path: 'signup',
              builder: (context, state) {
                _routerLogger.info("Navigating to /signup");
                return const SignupScreen();
              },
            ),
            GoRoute(
              path: 'registration',
              builder: (context, state) {
                _routerLogger.info("Navigating to /registration");
                return const SignupScreen();
              },
            ),
            GoRoute(
              path: 'verify',
              builder: (context, state) {
                _routerLogger.info("Navigating to /verify (query)");
                return LoginScreen(key: state.pageKey);
              },
            ),
            GoRoute(
              path: 'verify/:token',
              builder: (context, state) {
                final token = state.pathParameters['token'];
                _routerLogger.info("Navigating to /verify with token: $token");
                return LoginScreen(
                  key: state.pageKey,
                  verificationToken: token,
                );
              },
            ),
            GoRoute(
              path: 'verification',
              builder: (context, state) {
                _routerLogger.info("Navigating to /verification");
                return LoginScreen(key: state.pageKey);
              },
            ),
            GoRoute(
              path: 'l/:shortCode',
              builder: (context, state) {
                final shortCode = state.pathParameters['shortCode'];
                _routerLogger.info("Navigating to /l with code: $shortCode");
                return LoginScreen(key: state.pageKey);
              },
            ),
            GoRoute(
              path: 'forgot-password',
              builder: (context, state) {
                _routerLogger.info("Navigating to /forgot-password");
                return const ForgotPasswordScreen();
              },
            ),
            GoRoute(
              path: 'recovery',
              builder: (context, state) {
                _routerLogger.info("Navigating to /recovery");
                return const ForgotPasswordScreen();
              },
            ),
            GoRoute(
              // Supports both /reset-password and /reset-password?token=...
              path: 'reset-password',
              builder: (context, state) {
                _routerLogger.info("Navigating to /reset-password");
                return const ResetPasswordScreen();
              },
            ),
            GoRoute(
              path: 'error',
              builder: (context, state) {
                _routerLogger.info("Navigating to /error");
                final params = state.uri.queryParameters;
                return ErrorScreen(
                  errorId: params['id'],
                  errorCode: params['error'],
                  description: params['error_description'] ?? params['message'],
                );
              },
            ),
            GoRoute(
              path: 'settings',
              builder: (context, state) {
                _routerLogger.info("Navigating to /settings (disabled)");
                return ErrorScreen(
                  errorCode: 'settings_disabled',
                  description: tr('msg.userfront.settings.disabled'),
                );
              },
            ),
            GoRoute(
              path: 'approve',
              builder: (context, state) {
                final ref = state.uri.queryParameters['ref'];
                _routerLogger.info("Navigating to /approve with ref: $ref");
                return ApproveQrScreen(pendingRef: ref);
              },
            ),
            GoRoute(
              path: 'ql/:ref',
              builder: (context, state) {
                final ref = state.pathParameters['ref'];
                _routerLogger.info("Navigating to /ql with ref: $ref");
                return ApproveQrScreen(pendingRef: ref);
              },
            ),
            GoRoute(
              path: 'scan',
              builder: (context, state) {
                _routerLogger.info("Navigating to /scan");
                return const QRScanScreen();
              },
            ),
            GoRoute(
              path: 'admin/users',
              builder: (context, state) {
                _routerLogger.info("Navigating to /admin/users");
                return const UserManagementScreen();
              },
            ),
          ],
        ),
      ],
    ),
  ],
  redirect: (context, state) {
    final requestedLocale = extractLocaleFromPath(state.uri);
    final preferredLocale = resolvePreferredLocaleCode();
    if (requestedLocale == null) {
      return buildLocalizedPath(preferredLocale, state.uri);
    }

    final hasStoredToken = AuthTokenStore.getToken() != null;
    final hasCookieSession = AuthTokenStore.usesCookie();
    final isLoggedIn = hasStoredToken || hasCookieSession;
    final path = stripLocalePath(state.uri);

    // Public paths that don't require login
    final isPublicPath =
        path == '/signin' ||
        path == '/signup' ||
        path == '/login' ||
        path == '/registration' ||
        path == '/verify' ||
        path == '/verification' ||
        path.startsWith('/verify/') ||
        path == '/approve' ||
        path.startsWith('/ql/') ||
        path == '/forgot-password' ||
        path == '/recovery' ||
        path == '/reset-password' ||
        path == '/error' ||
        path == '/settings' ||
        path == '/consent'; // Consent page is public

    _routerLogger.fine("Redirect check - Path: $path, IsLoggedIn: $isLoggedIn");

    // 0. ALWAYS allow public paths to proceed so they can function
    if (isPublicPath) {
      return null;
    }

    // If not logged in and trying to access a protected page, redirect to /signin
    if (!isLoggedIn) {
      _routerLogger.info("Not logged in, redirecting to /signin");
      return buildSigninRedirectPath(requestedLocale, state.uri);
    }

    // If logged in and trying to access login page, redirect to root (dashboard)
    // This is now implicitly handled by the isPublicPath check, but kept for clarity.
    // if (isLoggedIn && path == '/signin') {
    //   _routerLogger.info("Logged in, redirecting to /");
    //   return '/';
    // }

    return null;
  },
);

class BaronSSOApp extends StatelessWidget {
  const BaronSSOApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      title: tr('ui.userfront.app_title'),
      localizationsDelegates: context.localizationDelegates,
      supportedLocales: context.supportedLocales,
      locale: context.locale,
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: const Color(0xFF1A1F2C), // Dark Navy/Black base
          brightness: Brightness.light,
        ),
        useMaterial3: true,
        fontFamily: 'NotoSansKR',
        pageTransitionsTheme: const PageTransitionsTheme(
          builders: {
            TargetPlatform.android: NoTransitionsBuilder(),
            TargetPlatform.iOS: NoTransitionsBuilder(),
            TargetPlatform.linux: NoTransitionsBuilder(),
            TargetPlatform.macOS: NoTransitionsBuilder(),
            TargetPlatform.windows: NoTransitionsBuilder(),
            TargetPlatform.fuchsia: NoTransitionsBuilder(),
          },
        ),
      ),
      routerConfig: _router,
    );
  }
}

class NoTransitionsBuilder extends PageTransitionsBuilder {
  const NoTransitionsBuilder();

  @override
  Widget buildTransitions<T>(
    PageRoute<T> route,
    BuildContext context,
    Animation<double> animation,
    Animation<double> secondaryAnimation,
    Widget child,
  ) {
    return child;
  }
}