import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:local_auth/local_auth.dart';
import 'core/theme/app_theme.dart';
import 'core/theme/theme_provider.dart';
import 'features/auth/presentation/auth_screen.dart';
import 'features/auth/presentation/setup_wizard_screen.dart';
import 'features/dashboard/presentation/dashboard_screen.dart';
import 'features/onboarding/presentation/onboarding_screen.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'core/network/dio_client.dart';

final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(
    const ProviderScope(
      child: KifiApp(),
    ),
  );
}

class KifiApp extends ConsumerStatefulWidget {
  const KifiApp({super.key});

  @override
  ConsumerState<KifiApp> createState() => _KifiAppState();
}

class _KifiAppState extends ConsumerState<KifiApp> {
  bool _isLoading = true;
  bool _isAuthenticated = false;
  bool _isSetupCompleted = true;
  bool _hasSeenOnboarding = false;
  final LocalAuthentication _localAuth = LocalAuthentication();
  String? _startupError;

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

  Future<bool> _authenticateWithBiometrics() async {
    try {
      final isAvailable = await _localAuth.canCheckBiometrics;
      final isDeviceSupported = await _localAuth.isDeviceSupported();
      
      if (!isAvailable || !isDeviceSupported) {
        return true; // If device does not support biometrics, allow access via stored token
      }
      
      return await _localAuth.authenticate(
        localizedReason: 'Please authenticate to access Kifi',
        biometricOnly: true,
        persistAcrossBackgrounding: true,
      );
    } catch (e) {
      return false; // Fail safe
    }
  }

  Future<void> _checkAuthStatus() async {
    try {
      const storage = FlutterSecureStorage();
      final token = await storage.read(key: 'jwt_token');
      final prefs = await SharedPreferences.getInstance();
      final hasSeenOnboarding = prefs.getBool('has_seen_onboarding') ?? false;
      
      if (token != null && token.isNotEmpty) {
        // Prompt for biometrics if returning user
        final authSuccess = await _authenticateWithBiometrics();
        if (!authSuccess) {
          setState(() {
            _isAuthenticated = false;
            _hasSeenOnboarding = hasSeenOnboarding;
            _isLoading = false;
          });
          return; // User failed biometrics, leave them on login screen
        }

        // Validate token and check account setup status with backend
        try {
          final res = await DioClient().dio.get('/account/setup/status');
          final status = res.data != null ? res.data['status'] : null;

          setState(() {
            _isAuthenticated = true;
            _isSetupCompleted = status == 'COMPLETED';
            _hasSeenOnboarding = hasSeenOnboarding;
            _isLoading = false;
          });
        } catch (_) {
          // Token is stale / invalid / user was wiped from DB -> clear token and go to AuthScreen
          await storage.delete(key: 'jwt_token');
          await DioClient().clearToken();
          setState(() {
            _isAuthenticated = false;
            _hasSeenOnboarding = hasSeenOnboarding;
            _isLoading = false;
          });
        }
      } else {
        setState(() {
          _isAuthenticated = false;
          _hasSeenOnboarding = hasSeenOnboarding;
          _isLoading = false;
        });
      }
    } catch (e) {
      setState(() {
        _startupError = e.toString();
        _isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final themeMode = ref.watch(themeProvider);

    return MaterialApp(
      navigatorKey: navigatorKey,
      title: 'Kifi',
      debugShowCheckedModeBanner: false,
      theme: AppTheme.lightTheme,
      darkTheme: AppTheme.darkTheme,
      themeMode: themeMode,
      home: _startupError != null 
          ? Scaffold(body: Center(child: Padding(padding: const EdgeInsets.all(20), child: Text("Startup Error: $_startupError", style: const TextStyle(color: Colors.red)))))
          : _isLoading 
              ? const Scaffold(body: Center(child: CircularProgressIndicator()))
              : ((!kIsWeb && !_hasSeenOnboarding)
                  ? const OnboardingScreen() 
                  : (_isAuthenticated 
                      ? (_isSetupCompleted ? const DashboardScreen() : const SetupWizardScreen()) 
                      : const AuthScreen())),
    );
  }
}