import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:votianlt_app/services/developer.dart' as developer;
import 'package:flutter/material.dart';
import 'package:package_info_plus/package_info_plus.dart';
import 'services/websocket_service.dart';
import 'services/dart_mq.dart';
import 'services/database_service.dart';
import 'app_state.dart';
import 'l10n/app_localizations.dart';

class LoginView extends StatefulWidget {
  const LoginView({super.key, this.suppressConnectionSnack = false});

  // If true, suppress connection-related SnackBars until the user attempts login
  final bool suppressConnectionSnack;

  @override
  State<LoginView> createState() => _LoginViewState();
}

class _LoginViewState extends State<LoginView> {
  final _formKey = GlobalKey<FormState>();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  bool _isPasswordVisible = false;
  bool _isLoggingIn = false;
  final StompService _stompService = StompService();
  final AppState _appState = AppState();

  // DartMQ subscriptions for proper cleanup
  DartMQSubscription? _connectionStatusSubscription;
  DartMQSubscription? _authResponseSubscription;
  bool _logoutNoticeShown = false;
  bool _hasNavigatedToJobs = false;
  String _appVersion = '';

  @override
  void initState() {
    super.initState();
    // Pre-populate with test data
    if (kDebugMode) {
      _emailController.text = 'mail@svencarstensen.de';
      _passwordController.text = 'test123';
    }

    _loadAppVersion();
    _initializeStompService();

    // If we came here due to logout, show only a success message and suppress other connection snacks
    if (widget.suppressConnectionSnack && !_logoutNoticeShown) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (!mounted) return;
        _logoutNoticeShown = true;
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(AppLocalizations.of(context).loginSuccess), backgroundColor: Colors.green, duration: const Duration(seconds: 1)));
      });
    }
  }

  @override
  void dispose() {
    // Cancel all stream subscriptions to prevent setState() after dispose
    _connectionStatusSubscription?.cancel();
    _authResponseSubscription?.cancel();
    _emailController.dispose();
    _passwordController.dispose();

    // Don't dispose the singleton StompService as it may be used elsewhere
    // _stompService.dispose();

    super.dispose();
  }

  Future<void> _loadAppVersion() async {
    try {
      final PackageInfo packageInfo = await PackageInfo.fromPlatform();
      setState(() {
        _appVersion = packageInfo.version;
      });
    } catch (e) {
      developer.log('Error loading app version: $e', name: 'LoginView');
    }
  }

  void _initializeStompService() {
    // Listen to connection status changes via dart_mq
    // Note: Don't reset _isLoggingIn here - the login flow in _handleLogin
    // manages button state through its own error/success handling.
    _connectionStatusSubscription = DartMQ().subscribe<bool>(MQTopics.connectionStatus, (isConnected) {
      if (mounted) {
        setState(() {});
      }
    });

    // Listen to authentication responses via dart_mq
    _authResponseSubscription = DartMQ().subscribe<Map<String, dynamic>>(MQTopics.authResponse, (response) {
      final responseTime = DateTime.now();
      developer.log('=== AUTHENTICATION RESPONSE RECEIVED ===', name: 'LoginView');
      developer.log('Timestamp: ${responseTime.toIso8601String()}', name: 'LoginView');
      developer.log('Response data: $response', name: 'LoginView');

      if (mounted) {
        WidgetsBinding.instance.addPostFrameCallback((_) {
          if (!mounted) return;

          setState(() {
            _isLoggingIn = false;
          });

          if (response['success'] == true) {
            // Prevent duplicate navigation from multiple auth responses
            if (_hasNavigatedToJobs) {
              developer.log('Already navigated to jobs view - ignoring duplicate auth response', name: 'LoginView');
              return;
            }
            _hasNavigatedToJobs = true;

            final message = response['message'] ?? 'Anmeldung erfolgreich';
            final email = _emailController.text.trim();
            final password = _passwordController.text;

            developer.log('=== LOGIN SUCCESS ===', name: 'LoginView');
            developer.log('Email: $email', name: 'LoginView');
            developer.log('Message: $message', name: 'LoginView');

            // Store email as login identifier
            _appState.setLoggedInEmail(email);

            // Save credentials for auto-login on app restart
            DatabaseService().saveCredentials(email, password);

            // Navigate directly to jobs view - jobs will be loaded there
            developer.log('Navigating to jobs view - jobs will be loaded there...', name: 'LoginView');
            Navigator.of(context).pushReplacementNamed('/jobs');
          } else {
            final errorMessage = response['message'] ?? 'Unbekannter Fehler';
            final errorCode = response['code'] ?? 'No code';

            developer.log('=== LOGIN FAILURE ===', name: 'LoginView');
            developer.log('Error message: $errorMessage', name: 'LoginView');
            developer.log('Error code: $errorCode', name: 'LoginView');
            developer.log('Full error response: $response', name: 'LoginView');

            ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('${AppLocalizations.of(context).loginFailed}: $errorMessage'), backgroundColor: Colors.red, duration: const Duration(seconds: 1)));
          }
        });
      } else {
        developer.log('Widget not mounted - skipping UI updates for auth response', name: 'LoginView');
      }

      developer.log('Authentication response processing completed', name: 'LoginView');
    });
  }

  Future<void> _handleLogin() async {
    final loginStartTime = DateTime.now();
    final sessionId = loginStartTime.millisecondsSinceEpoch.toString();

    developer.log('=== LOGIN ATTEMPT STARTED ===', name: 'LoginView');
    developer.log('Session ID: $sessionId', name: 'LoginView');
    developer.log('Timestamp: ${loginStartTime.toIso8601String()}', name: 'LoginView');

    if (!_formKey.currentState!.validate()) {
      developer.log('Login validation failed - form is invalid', name: 'LoginView');
      return;
    }

    if (_isLoggingIn) {
      developer.log('Login already in progress - ignoring duplicate request', name: 'LoginView');
      return;
    }

    String email = _emailController.text.trim();
    developer.log('Login attempt for email: $email', name: 'LoginView');
    developer.log('Password length: ${_passwordController.text.length} characters', name: 'LoginView');

    // Capture ScaffoldMessenger and localizations before any async operations
    final scaffoldMessenger = ScaffoldMessenger.of(context);
    final localizations = AppLocalizations.of(context);

    if (!_stompService.isConnected) {
      developer.log('Not connected to STOMP server - establishing connection first', name: 'LoginView');
      developer.log('STOMP service connection state: ${_stompService.isConnected}', name: 'LoginView');

      // Always attempt connection to fixed STOMP endpoint (no discovery gating)
      // Show connecting message
      if (!widget.suppressConnectionSnack) {
        scaffoldMessenger.showSnackBar(SnackBar(content: Text(localizations.connecting), backgroundColor: Colors.blue, duration: const Duration(seconds: 1)));
      }

      // Set loading state
      setState(() {
        _isLoggingIn = true;
      });

      try {
        // Start connection to STOMP server
        await _stompService.connect();

        // Check if already connected after connect returns
        if (!_stompService.isConnected) {
          // Wait for connection to be established with a timeout
          try {
            final completer = Completer<bool>();
            final subscription = DartMQ().subscribe<bool>(MQTopics.connectionStatus, (isConnected) {
              if (isConnected && !completer.isCompleted) {
                completer.complete(true);
              }
            });

            await completer.future.timeout(const Duration(seconds: 12));
            subscription.cancel();
            developer.log('STOMP connection established - proceeding with login', name: 'LoginView');
          } on TimeoutException {
            developer.log('STOMP connection timed out', name: 'LoginView');
          }
        } else {
          developer.log('STOMP already connected after connect - proceeding with login', name: 'LoginView');
        }

        // Check if connection was successful
        if (!_stompService.isConnected) {
          setState(() {
            _isLoggingIn = false;
          });
          scaffoldMessenger.showSnackBar(SnackBar(content: Text(localizations.connectionTimeout), backgroundColor: Colors.red, duration: const Duration(seconds: 2)));
          return;
        }
      } catch (e, stackTrace) {
        setState(() {
          _isLoggingIn = false;
        });
        developer.log('Error connecting to STOMP server: $e', name: 'LoginView');
        developer.log('Stack trace: $stackTrace', name: 'LoginView');
        scaffoldMessenger.showSnackBar(SnackBar(content: Text('${localizations.connectionError}: $e'), backgroundColor: Colors.red, duration: const Duration(seconds: 1)));
        return;
      }
    }

    developer.log('Pre-login checks passed - initiating login request', name: 'LoginView');
    developer.log('Connection status: connected=${_stompService.isConnected}', name: 'LoginView');

    setState(() {
      _isLoggingIn = true;
    });

    String password = _passwordController.text;

    developer.log('Sending login request via STOMP service...', name: 'LoginView');

    try {
      // Send login request via STOMP
      await _stompService.login(email, password);

      final requestSentTime = DateTime.now();
      final requestDuration = requestSentTime.difference(loginStartTime).inMilliseconds;
      developer.log('Login request sent successfully after ${requestDuration}ms', name: 'LoginView');
    } catch (e, stackTrace) {
      final errorTime = DateTime.now();
      final errorDuration = errorTime.difference(loginStartTime).inMilliseconds;

      developer.log('LOGIN ERROR: Exception during login request after ${errorDuration}ms', name: 'LoginView');
      developer.log('Error: $e', name: 'LoginView');
      developer.log('Stack trace: $stackTrace', name: 'LoginView');

      setState(() {
        _isLoggingIn = false;
      });

      scaffoldMessenger.showSnackBar(SnackBar(content: Text('${localizations.loginError}: $e'), backgroundColor: Colors.red, duration: const Duration(seconds: 1)));
    }

    // The auth response will be handled by the stream listener
    // _isLoggingIn will be set to false in the listener
    developer.log('Login request phase completed - waiting for auth response', name: 'LoginView');
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.grey[50],
      body: Column(
        children: [
          Expanded(
            child: SafeArea(
              child: Center(
                child: SingleChildScrollView(
                  padding: const EdgeInsets.all(24.0),
                  child: Form(
                    key: _formKey,
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      crossAxisAlignment: CrossAxisAlignment.stretch,
                      children: [
                        // Logo oder App-Name
                        Icon(Icons.account_circle, size: 100, color: Colors.deepPurple),
                        const SizedBox(height: 32),

                        Text(AppLocalizations.of(context).welcomeBack, style: Theme.of(context).textTheme.headlineMedium?.copyWith(fontWeight: FontWeight.bold, color: Colors.grey[800]), textAlign: TextAlign.center),
                        const SizedBox(height: 8),

                        Text(AppLocalizations.of(context).loginSubtitle, style: Theme.of(context).textTheme.bodyLarge?.copyWith(color: Colors.grey[600]), textAlign: TextAlign.center),
                        const SizedBox(height: 32),
                        // E-Mail-Feld
                        TextFormField(
                          controller: _emailController,
                          keyboardType: TextInputType.emailAddress,
                          decoration: InputDecoration(labelText: 'E-Mail-Adresse', hintText: 'Geben Sie Ihre E-Mail-Adresse ein', prefixIcon: const Icon(Icons.email_outlined), border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)), filled: true, fillColor: Colors.white),
                          validator: (value) {
                            if (value == null || value.isEmpty) {
                              return 'Bitte geben Sie Ihre E-Mail-Adresse ein';
                            }
                            if (!RegExp(r'^[A-Za-z0-9_.+-]+@[A-Za-z0-9-]+\.[A-Za-z0-9.-]+$').hasMatch(value)) {
                              return 'Bitte geben Sie eine gültige E-Mail-Adresse ein';
                            }
                            return null;
                          },
                        ),
                        const SizedBox(height: 16),

                        // Passwort-Feld
                        TextFormField(
                          controller: _passwordController,
                          obscureText: !_isPasswordVisible,
                          decoration: InputDecoration(
                            labelText: 'Passwort',
                            hintText: 'Geben Sie Ihr Passwort ein',
                            prefixIcon: const Icon(Icons.lock_outlined),
                            suffixIcon: IconButton(
                              icon: Icon(_isPasswordVisible ? Icons.visibility : Icons.visibility_off),
                              onPressed: () {
                                setState(() {
                                  _isPasswordVisible = !_isPasswordVisible;
                                });
                              },
                            ),
                            border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)),
                            filled: true,
                            fillColor: Colors.white,
                          ),
                          validator: (value) {
                            if (value == null || value.isEmpty) {
                              return 'Bitte geben Sie Ihr Passwort ein';
                            }
                            if (value.length < 6) {
                              return 'Das Passwort muss mindestens 6 Zeichen lang sein';
                            }
                            return null;
                          },
                        ),
                        const SizedBox(height: 24),

                        // Passwort vergessen Link
                        Align(
                          alignment: Alignment.centerRight,
                          child: TextButton(
                            onPressed: () {
                              // Hier würde die "Passwort vergessen" Funktionalität implementiert werden
                              ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(AppLocalizations.of(context).forgotPasswordMessage), duration: const Duration(seconds: 1)));
                            },
                            child: Text(AppLocalizations.of(context).forgotPassword, style: const TextStyle(color: Colors.deepPurple, fontWeight: FontWeight.w500)),
                          ),
                        ),
                        const SizedBox(height: 24),

                        // Verbindungsstatus
                        // Anmelden Button
                        ElevatedButton(onPressed: _isLoggingIn ? null : _handleLogin, style: ElevatedButton.styleFrom(backgroundColor: Colors.deepPurple, foregroundColor: Colors.white, padding: const EdgeInsets.symmetric(vertical: 16), shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)), elevation: 2), child: _isLoggingIn ? Row(mainAxisAlignment: MainAxisAlignment.center, children: const [SizedBox(width: 18, height: 18, child: CircularProgressIndicator(strokeWidth: 2.5, valueColor: AlwaysStoppedAnimation<Color>(Colors.white))), SizedBox(width: 12), Text('Verbinden…', style: TextStyle(fontSize: 16, fontWeight: FontWeight.w600))]) : const Text('Anmelden', style: TextStyle(fontSize: 16, fontWeight: FontWeight.w600))),
                        const SizedBox(height: 24),
                      ],
                    ),
                  ),
                ),
              ),
            ),
          ),
          // Version number at the bottom
          if (_appVersion.isNotEmpty) Padding(padding: const EdgeInsets.only(bottom: 16.0), child: Text('Version $_appVersion', style: TextStyle(fontSize: 12, color: Colors.grey[500]), textAlign: TextAlign.center)),
        ],
      ),
    );
  }
}