import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:supabase_flutter/supabase_flutter.dart';
import 'login_screen.dart';
import 'register_screen.dart';
import '../services/auth_service.dart';

import 'dart:io' show Platform;

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

  @override
  State<AuthScreen> createState() => _AuthScreenState();
}

class _AuthScreenState extends State<AuthScreen>
  with SingleTickerProviderStateMixin {
  final SupabaseClient supabase = Supabase.instance.client;
  final AuthService _authService = AuthService();
  late TabController _tabController;
  bool _isLoading = true;

  @override
  void initState() {
    super.initState();
    debugPrint('AuthScreen initState started');
    _tabController = TabController(length: 2, vsync: this);
    _setupAuthListener();
    _checkAutoLogin();
    debugPrint('AuthScreen initState completed');
  }


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

  void _setupAuthListener() {
    supabase.auth.onAuthStateChange.listen((data) {
      final event = data.event;
      if (event == AuthChangeEvent.signedIn) {
        setState(() {
          _isLoading = false;
        });
        // Navigate to home screen
        if (mounted) {
          Navigator.of(context).pushReplacementNamed('/home');
        }
      } else if (event == AuthChangeEvent.signedOut) {
        setState(() {
          _isLoading = false;
        });
      }
    });
  }

  Future<void> _checkAutoLogin() async {
    debugPrint('_checkAutoLogin started');
    try {
      // Add timeout to prevent hanging
      await Future.any([
        _performAutoLogin(),
        Future.delayed(const Duration(seconds: 10)),
      ]);
      debugPrint('_checkAutoLogin completed');
    } catch (e) {
      debugPrint('_checkAutoLogin error: $e');
      setState(() {
        _isLoading = false;
      });
    }
  }

  Future<void> _performAutoLogin() async {
    debugPrint('_performAutoLogin started');
    // Check if user is already authenticated
    if (_authService.isAuthenticated) {
      debugPrint('User already authenticated, navigating to home');
      setState(() {
        _isLoading = false;
      });
      // Navigate to home screen immediately
      if (mounted) {
        Navigator.of(context).pushReplacementNamed('/home');
      }
      return;
    }

    debugPrint('Attempting auto-login with saved credentials');
    // Try auto-login with saved credentials
    final success = await _authService.autoLogin();
    debugPrint('Auto-login result: $success');
    setState(() {
      _isLoading = false;
    });
    // Let the auth listener handle navigation if successful
  }

Future<AuthResponse> googleSignInNative() async {
  /// TODO: update the Web client ID with your own.
  ///
  /// Web Client ID that you registered with Google Cloud.
  const webClientId = '311478513323-4vj6v6d254jbs8tt334u4874see8i4vj.apps.googleusercontent.com';

  /// TODO: update the iOS client ID with your own.
  ///
  /// iOS Client ID that you registered with Google Cloud.
  const iosClientId = '311478513323-8j9q5oe77hnmcmn7i6qsq5r7t0krrlb1.apps.googleusercontent.com';

  // Google sign in on Android will work without providing the Android
  // Client ID registered on Google Cloud.

  final GoogleSignIn signIn = GoogleSignIn(
    clientId: iosClientId,
    serverClientId: webClientId,
  );

  final googleUser = await signIn.signIn();
  if (googleUser == null) {
    throw Exception('Google sign-in was cancelled');
  }

  final googleAuth = await googleUser.authentication;
  final accessToken = googleAuth.accessToken;
  final idToken = googleAuth.idToken;

  if(accessToken == null){
    throw Exception('No access token found');
  }
  if(idToken == null){
    throw Exception('No id token found');
  }

  final response = await supabase.auth.signInWithIdToken(
    provider: OAuthProvider.google,
    idToken: idToken,
    accessToken: accessToken,
  );

  // Save user information after successful OAuth login
  final user = response.user;
  if (user != null) {
    final userName = googleUser.displayName ?? user.userMetadata?['name'] ?? 'User';
    final userEmail = googleUser.email;
    
    await _authService.saveUserInfo(
      name: userName,
      email: userEmail,
    );
  }

  return response;
}

Future<void> oauthLoginWeb(OAuthProvider provider) async {
  await supabase.auth.signInWithOAuth(
  provider,
  redirectTo: kIsWeb ? null : 'com.Xperience.TaskTracker.tasktracker://callback',
);
}

  Future<void> login(String email, String password, bool rememberMe) async {
    await _authService.loginWithPassword(
      email: email,
      password: password,
      rememberMe: rememberMe,
    );
  }

  Future<void> register(String email, String password, String name, bool rememberMe) async {
    await _authService.registerUser(
      email: email,
      password: password,
      name: name,
      rememberMe: rememberMe,
    );
  }

  Future<void> logout() async {
    await _authService.logout();
  }


  Future<void> oAuthLogin(OAuthProvider provider) async {
    try {
      if(Platform.isAndroid && provider == OAuthProvider.google){
        await googleSignInNative();
      } else {
        await oauthLoginWeb(provider);
      }
    } catch (e) {
      // Handle OAuth login errors
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('OAuth login failed: ${e.toString()}'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final screenHeight = MediaQuery.of(context).size.height;

    // Show loading screen while checking authentication
    if (_isLoading) {
      return Scaffold(
        backgroundColor: Colors.grey[50],
        body: const Center(
          child: CircularProgressIndicator(),
        ),
      );
    }

    return Scaffold(
      backgroundColor: Colors.grey[50],
      body: SafeArea(
        child: SingleChildScrollView(
          child: Column(
            children: [
              // Header Section
              Container(
                width: double.infinity,
                padding: const EdgeInsets.all(32.0),
                child: Column(
                  children: [
                    const SizedBox(height: 40),
                    // App Logo/Icon
                    Container(
                      width: 80,
                      height: 80,
                      decoration: BoxDecoration(
                        color: Theme.of(context).primaryColor,
                        borderRadius: BorderRadius.circular(20),
                        boxShadow: [
                          BoxShadow(
                            color: Theme.of(context).primaryColor.withValues(alpha: 0.3),
                            blurRadius: 20,
                            offset: const Offset(0, 10),
                          ),
                        ],
                      ),
                      child: const Icon(
                        Icons.task_alt,
                        color: Colors.white,
                        size: 40,
                      ),
                    ),
                    const SizedBox(height: 24),
                    Text(
                      'TaskTracker',
                      style: GoogleFonts.poppins(
                        fontSize: 32,
                        fontWeight: FontWeight.bold,
                        color: Colors.grey[800],
                      ),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      'Manage your tasks efficiently',
                      style: GoogleFonts.poppins(
                        fontSize: 16,
                        color: Colors.grey[600],
                      ),
                    ),
                  ],
                ),
              ),
              
              // Tab Bar
              Container(
                margin: const EdgeInsets.symmetric(horizontal: 24),
                decoration: BoxDecoration(
                  color: Colors.white,
                  borderRadius: BorderRadius.circular(12),
                  boxShadow: [
                    BoxShadow(
                      color: Colors.grey.withValues(alpha: 0.1),
                      blurRadius: 10,
                      offset: const Offset(0, 5),
                    ),
                  ],
                ),
                child: TabBar(
                  controller: _tabController,
                  indicator: BoxDecoration(
                    borderRadius: BorderRadius.circular(20),
                    color: Theme.of(context).primaryColor,
                  ),
                  indicatorSize: TabBarIndicatorSize.tab, // Make indicator fill the tab
                  labelColor: Colors.white,
                  unselectedLabelColor: Colors.grey[600],
                  labelStyle: GoogleFonts.poppins(
                    fontWeight: FontWeight.w600,
                    fontSize: 16,
                  ),
                  unselectedLabelStyle: GoogleFonts.poppins(
                    fontWeight: FontWeight.w500,
                    fontSize: 16,
                  ),
                  tabs: const [
                    Tab(text: 'Login'),
                    Tab(text: 'Register'),
                  ],
                ),
              ),
              
              const SizedBox(height: 24),
              
              // Tab Views
              SizedBox(
                height: screenHeight * 0.8,
                child: TabBarView(
                  controller: _tabController,
                  children: [
                    LoginScreen(
                      onLogin: login,
                      onOAuthLogin: (provider) => oAuthLogin(provider),
                    ),
                    RegisterScreen(
                      onRegister: register,
                      onOAuthRegister: (provider) => oAuthLogin(provider),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}