import 'package:flutter/material.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'theme/app_theme.dart';
import 'screens/login_screen.dart';
import 'screens/home_shell.dart';

// Re-export so other files can `import '../main.dart'` for these.
export 'package:supabase_flutter/supabase_flutter.dart'
    show AuthException, UserAttributes;

// ── Supabase credentials ──────────────────────────────────────────────
const _supabaseUrl = 'https://yaopcyubateifnicpywp.supabase.co';
const _supabaseAnonKey = 'sb_publishable_a7czIl7-TGeBJvid9z2XZA_3ElImliL';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await Supabase.initialize(
    url: _supabaseUrl,
    anonKey: _supabaseAnonKey,
  );

  runApp(const HWHubApp());
}

/// Convenience accessor used throughout the app.
final supabase = Supabase.instance.client;

/// Global keys so dialogs & snackbars survive widget-tree rebuilds.
final navigatorKey = GlobalKey<NavigatorState>();
final scaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();

/// Show a snackbar safely through the global key.
void showGlobalSnackBar(String message, {bool isError = false}) {
  scaffoldMessengerKey.currentState?.showSnackBar(
    SnackBar(
      content: Text(message),
      backgroundColor: isError ? Colors.red : null,
    ),
  );
}

/// Show a dialog safely through the global navigator key.
Future<T?> showGlobalDialog<T>({required WidgetBuilder builder}) {
  return showDialog<T>(
    context: navigatorKey.currentContext!,
    builder: builder,
  );
}

// ── Root App Widget ───────────────────────────────────────────────────
class HWHubApp extends StatelessWidget {
  const HWHubApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'HW Collector Hub',
      debugShowCheckedModeBanner: false,
      navigatorKey: navigatorKey,
      scaffoldMessengerKey: scaffoldMessengerKey,
      theme: AppTheme.light,
      darkTheme: AppTheme.dark,
      themeMode: ThemeMode.system,
      home: const AuthGate(),
    );
  }
}

// ── Auth Gate ─────────────────────────────────────────────────────────
class AuthGate extends StatefulWidget {
  const AuthGate({super.key});

  @override
  State<AuthGate> createState() => _AuthGateState();
}

class _AuthGateState extends State<AuthGate> {
  bool _isLoading = true;
  Session? _session;

  @override
  void initState() {
    super.initState();

    _session = supabase.auth.currentSession;

    supabase.auth.onAuthStateChange.listen(
      (AuthState authState) {
        if (!mounted) return;

        final wasLoggedIn = _session != null;
        final isLoggedIn = authState.session != null;
        _session = authState.session;

        if (wasLoggedIn != isLoggedIn) {
          setState(() {});
        }

        if (authState.event == AuthChangeEvent.passwordRecovery) {
          _showResetPasswordDialog();
        }
      },
      onError: (error) {
        showGlobalSnackBar('Auth error: $error', isError: true);
      },
    );

    setState(() => _isLoading = false);
  }

  Future<void> _showResetPasswordDialog() async {
    await showDialog<void>(
      context: navigatorKey.currentContext!,
      barrierDismissible: false,
      builder: (_) => const _ResetPasswordDialog(),
    );
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return const Scaffold(
        body: Center(child: CircularProgressIndicator()),
      );
    }
    return _session != null ? const HomeShell() : const LoginScreen();
  }
}

// ── Reset Password Dialog ─────────────────────────────────────────────
class _ResetPasswordDialog extends StatefulWidget {
  const _ResetPasswordDialog();

  @override
  State<_ResetPasswordDialog> createState() => _ResetPasswordDialogState();
}

class _ResetPasswordDialogState extends State<_ResetPasswordDialog> {
  final _passwordController = TextEditingController();
  bool _isSaving = false;

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

  Future<void> _save() async {
    final newPassword = _passwordController.text.trim();
    if (newPassword.length < 6) {
      showGlobalSnackBar('Password must be at least 6 characters.');
      return;
    }

    setState(() => _isSaving = true);

    try {
      await supabase.auth.updateUser(
        UserAttributes(password: newPassword),
      );
      if (!mounted) return;
      Navigator.of(context).pop();
      showGlobalSnackBar('Password updated successfully!');
    } on AuthException catch (e) {
      if (!mounted) return;
      setState(() => _isSaving = false);
      showGlobalSnackBar(e.message, isError: true);
    }
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Set New Password'),
      content: TextField(
        controller: _passwordController,
        obscureText: true,
        decoration: const InputDecoration(labelText: 'New password'),
        onSubmitted: (_) => _save(),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        ElevatedButton(
          onPressed: _isSaving ? null : _save,
          child: _isSaving
              ? const SizedBox(
                  height: 18,
                  width: 18,
                  child: CircularProgressIndicator(strokeWidth: 2),
                )
              : const Text('Save'),
        ),
      ],
    );
  }
}