import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:provider/provider.dart';

import '../../../core/constants/env_config.dart';
import '../../../core/theme/theme_provider.dart';
import '../../../core/utils/validators.dart';
import '../../../data/datasources/user_remote_data_source.dart';
import '../../../data/models/user_model.dart';
import '../../../data/services/preferences_helper.dart';
import '../../../data/services/secure_storage.dart';
import '../../widgets/custom_button.dart';
import '../login/login_screen.dart';

/// Écran d'inscription avec design moderne et compact.
///
/// Cet écran permet aux utilisateurs de créer un nouveau compte avec
/// validation des champs, gestion d'erreurs, et interface optimisée.
///
/// **Fonctionnalités:**
/// - Validation des champs en temps réel
/// - Vérification de correspondance des mots de passe
/// - Affichage/masquage du mot de passe
/// - Gestion d'erreurs robuste
/// - Support du thème clair/sombre
class SignUpScreen extends StatefulWidget {
  const SignUpScreen({super.key});

  @override
  State<SignUpScreen> createState() => _SignUpScreenState();
}

class _SignUpScreenState extends State<SignUpScreen>
    with SingleTickerProviderStateMixin {
  // ============================================================================
  // FORMULAIRE
  // ============================================================================

  final _formKey = GlobalKey<FormState>();
  final _lastNameController = TextEditingController();
  final _firstNameController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  final _confirmPasswordController = TextEditingController();

  // ============================================================================
  // ÉTATS
  // ============================================================================

  bool _isPasswordVisible = false;
  bool _isSubmitting = false;
  String? _errorMessage;

  // ============================================================================
  // SERVICES
  // ============================================================================

  late final UserRemoteDataSource _userRemoteDataSource;
  late final SecureStorage _secureStorage;
  late final PreferencesHelper _preferencesHelper;

  // ============================================================================
  // ANIMATIONS
  // ============================================================================

  late AnimationController _animationController;
  late Animation<double> _fadeAnimation;

  @override
  void initState() {
    super.initState();
    _initializeServices();
    _initializeAnimations();
  }

  void _initializeServices() {
    _userRemoteDataSource = UserRemoteDataSource(http.Client());
    _secureStorage = SecureStorage();
    _preferencesHelper = PreferencesHelper();
  }

  void _initializeAnimations() {
    _animationController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 800),
    );
    _fadeAnimation = CurvedAnimation(
      parent: _animationController,
      curve: Curves.easeIn,
    );
    _animationController.forward();
  }

  @override
  void dispose() {
    _lastNameController.dispose();
    _firstNameController.dispose();
    _emailController.dispose();
    _passwordController.dispose();
    _confirmPasswordController.dispose();
    _animationController.dispose();
    super.dispose();
  }

  // ============================================================================
  // ACTIONS
  // ============================================================================

  /// Bascule la visibilité du mot de passe.
  void _togglePasswordVisibility() {
    setState(() {
      _isPasswordVisible = !_isPasswordVisible;
    });
  }

  /// Soumet le formulaire d'inscription.
  Future<void> _handleSubmit() async {
    if (!_formKey.currentState!.validate()) {
      return;
    }

    // Vérifier la correspondance des mots de passe
    if (_passwordController.text != _confirmPasswordController.text) {
      setState(() {
        _errorMessage = 'Les mots de passe ne correspondent pas';
      });
      return;
    }

    setState(() {
      _isSubmitting = true;
      _errorMessage = null;
    });

    try {
      final user = UserModel(
        userId: '',
        userLastName: _lastNameController.text.trim(),
        userFirstName: _firstNameController.text.trim(),
        email: _emailController.text.trim(),
        motDePasse: _passwordController.text,
        profileImageUrl: '',
      );

      final createdUser = await _userRemoteDataSource.createUser(user);

      await _saveUserData(createdUser);
      await _navigateToLogin();
    } catch (e) {
      _handleError(e);
    } finally {
      if (mounted) {
        setState(() {
          _isSubmitting = false;
        });
      }
    }
  }

  /// Sauvegarde les données utilisateur.
  Future<void> _saveUserData(UserModel user) async {
    await _secureStorage.saveUserId(user.userId);
    await _preferencesHelper.saveUserName(user.userLastName);
    await _preferencesHelper.saveUserLastName(user.userFirstName);
  }

  /// Navigue vers l'écran de connexion.
  Future<void> _navigateToLogin() async {
    if (!mounted) return;

    Navigator.pushReplacement(
      context,
      MaterialPageRoute(
        builder: (context) => const LoginScreen(),
      ),
    );

    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('Compte créé avec succès ! Connectez-vous maintenant'),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  /// Gère les erreurs d'inscription.
  void _handleError(Object error) {
    String message = 'Erreur lors de la création du compte';

    if (error.toString().contains('Conflict') ||
        error.toString().contains('existe déjà')) {
      message = 'Un compte avec cet email existe déjà';
    } else if (error.toString().contains('network') ||
        error.toString().contains('timeout')) {
      message = 'Problème de connexion. Vérifiez votre réseau';
    } else {
      message = error.toString().replaceAll('Exception: ', '');
    }

    setState(() {
      _errorMessage = message;
    });

    if (EnvConfig.enableDetailedLogs) {
      debugPrint('[SignUpScreen] Erreur: $error');
    }
  }

  // ============================================================================
  // BUILD
  // ============================================================================

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final isKeyboardVisible = MediaQuery.of(context).viewInsets.bottom > 0;

    return Scaffold(
      body: Stack(
        children: [
          _buildBackground(theme),
          _buildContent(theme, isKeyboardVisible),
          _buildThemeToggle(theme),
          if (_isSubmitting) _buildLoadingOverlay(theme),
        ],
      ),
    );
  }

  /// Construit l'arrière-plan avec dégradé.
  Widget _buildBackground(ThemeData theme) {
    return AnimatedContainer(
      duration: const Duration(seconds: 3),
      decoration: BoxDecoration(
        gradient: LinearGradient(
          colors: [
            theme.colorScheme.primary,
            theme.colorScheme.secondary,
          ],
          begin: Alignment.topLeft,
          end: Alignment.bottomRight,
        ),
      ),
    );
  }

  /// Construit le contenu principal.
  Widget _buildContent(ThemeData theme, bool isKeyboardVisible) {
    return FadeTransition(
      opacity: _fadeAnimation,
      child: Center(
        child: SingleChildScrollView(
          padding: const EdgeInsets.all(24),
          child: Form(
            key: _formKey,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                if (!isKeyboardVisible) _buildLogo(theme),
                if (!isKeyboardVisible) const SizedBox(height: 32),
                _buildTitle(theme),
                const SizedBox(height: 32),
                _buildLastNameField(theme),
                const SizedBox(height: 16),
                _buildFirstNameField(theme),
                const SizedBox(height: 16),
                _buildEmailField(theme),
                const SizedBox(height: 16),
                _buildPasswordField(theme),
                const SizedBox(height: 16),
                _buildConfirmPasswordField(theme),
                const SizedBox(height: 24),
                _buildSubmitButton(theme),
                const SizedBox(height: 16),
                _buildLoginLink(theme),
                if (_errorMessage != null) _buildErrorMessage(theme),
              ],
            ),
          ),
        ),
      ),
    );
  }

  /// Construit le logo.
  Widget _buildLogo(ThemeData theme) {
    return Image.asset(
      'lib/assets/images/logo.png',
      height: 100,
      errorBuilder: (context, error, stackTrace) {
        return Icon(
          Icons.person_add,
          size: 64,
          color: theme.colorScheme.onPrimary,
        );
      },
    );
  }

  /// Construit le titre.
  Widget _buildTitle(ThemeData theme) {
    return Text(
      'Créer un compte',
      style: theme.textTheme.headlineSmall?.copyWith(
        color: theme.colorScheme.onPrimary,
        fontWeight: FontWeight.bold,
      ),
      textAlign: TextAlign.center,
    );
  }

  /// Construit le champ nom.
  Widget _buildLastNameField(ThemeData theme) {
    return TextFormField(
      controller: _lastNameController,
      textInputAction: TextInputAction.next,
      decoration: _buildInputDecoration(
        theme,
        'Nom',
        Icons.person,
      ),
      style: TextStyle(color: theme.colorScheme.onPrimary),
      validator: (value) => Validators.validateName(value, fieldName: 'le nom'),
    );
  }

  /// Construit le champ prénom.
  Widget _buildFirstNameField(ThemeData theme) {
    return TextFormField(
      controller: _firstNameController,
      textInputAction: TextInputAction.next,
      decoration: _buildInputDecoration(
        theme,
        'Prénoms',
        Icons.person_outline,
      ),
      style: TextStyle(color: theme.colorScheme.onPrimary),
      validator: (value) =>
          Validators.validateName(value, fieldName: 'le prénom'),
    );
  }

  /// Construit le champ email.
  Widget _buildEmailField(ThemeData theme) {
    return TextFormField(
      controller: _emailController,
      keyboardType: TextInputType.emailAddress,
      textInputAction: TextInputAction.next,
      decoration: _buildInputDecoration(
        theme,
        'Email',
        Icons.email,
      ),
      style: TextStyle(color: theme.colorScheme.onPrimary),
      validator: Validators.validateEmail,
    );
  }

  /// Construit le champ mot de passe.
  Widget _buildPasswordField(ThemeData theme) {
    return TextFormField(
      controller: _passwordController,
      obscureText: !_isPasswordVisible,
      textInputAction: TextInputAction.next,
      decoration: _buildInputDecoration(
        theme,
        'Mot de passe',
        Icons.lock,
        suffixIcon: IconButton(
          icon: Icon(
            _isPasswordVisible ? Icons.visibility : Icons.visibility_off,
            color: theme.colorScheme.onPrimary.withOpacity(0.7),
          ),
          onPressed: _togglePasswordVisibility,
        ),
      ),
      style: TextStyle(color: theme.colorScheme.onPrimary),
      validator: (value) => Validators.validatePassword(value, minLength: 6),
    );
  }

  /// Construit le champ confirmation mot de passe.
  Widget _buildConfirmPasswordField(ThemeData theme) {
    return TextFormField(
      controller: _confirmPasswordController,
      obscureText: !_isPasswordVisible,
      textInputAction: TextInputAction.done,
      onFieldSubmitted: (_) => _handleSubmit(),
      decoration: _buildInputDecoration(
        theme,
        'Confirmer le mot de passe',
        Icons.lock_outline,
        suffixIcon: IconButton(
          icon: Icon(
            _isPasswordVisible ? Icons.visibility : Icons.visibility_off,
            color: theme.colorScheme.onPrimary.withOpacity(0.7),
          ),
          onPressed: _togglePasswordVisibility,
        ),
      ),
      style: TextStyle(color: theme.colorScheme.onPrimary),
      validator: (value) => Validators.validatePasswordMatch(
        _passwordController.text,
        value,
      ),
    );
  }

  /// Construit le bouton de soumission (compact).
  Widget _buildSubmitButton(ThemeData theme) {
    return SizedBox(
      width: double.infinity,
      child: CustomButton(
        text: 'Créer un compte',
        icon: Icons.person_add,
        onPressed: () => _handleSubmit(),
        isLoading: _isSubmitting,
        isEnabled: !_isSubmitting,
        variant: ButtonVariant.primary,
        size: ButtonSize.medium,
      ),
    );
  }

  /// Construit le lien vers la connexion.
  Widget _buildLoginLink(ThemeData theme) {
    return TextButton(
      onPressed: () => Navigator.pop(context),
      child: Text(
        'Déjà un compte ? Connectez-vous',
        style: theme.textTheme.bodyMedium?.copyWith(
          color: theme.colorScheme.onPrimary.withOpacity(0.9),
          decoration: TextDecoration.underline,
        ),
      ),
    );
  }

  /// Construit le message d'erreur.
  Widget _buildErrorMessage(ThemeData theme) {
    return Padding(
      padding: const EdgeInsets.only(top: 16),
      child: Container(
        padding: const EdgeInsets.all(12),
        decoration: BoxDecoration(
          color: theme.colorScheme.error.withOpacity(0.1),
          borderRadius: BorderRadius.circular(8),
          border: Border.all(
            color: theme.colorScheme.error.withOpacity(0.3),
          ),
        ),
        child: Row(
          children: [
            Icon(
              Icons.error_outline,
              color: theme.colorScheme.error,
              size: 20,
            ),
            const SizedBox(width: 8),
            Expanded(
              child: Text(
                _errorMessage!,
                style: theme.textTheme.bodySmall?.copyWith(
                  color: theme.colorScheme.error,
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  /// Construit le bouton de basculement de thème.
  Widget _buildThemeToggle(ThemeData theme) {
    return Positioned(
      top: MediaQuery.of(context).padding.top + 8,
      right: 16,
      child: IconButton(
        icon: Icon(
          Provider.of<ThemeProvider>(context).isDarkMode
              ? Icons.light_mode
              : Icons.dark_mode,
          color: theme.colorScheme.onPrimary,
        ),
        onPressed: () {
          Provider.of<ThemeProvider>(context, listen: false).toggleTheme();
        },
        tooltip: 'Changer le thème',
      ),
    );
  }

  /// Construit l'overlay de chargement.
  Widget _buildLoadingOverlay(ThemeData theme) {
    return Container(
      color: Colors.black.withOpacity(0.3),
      child: Center(
        child: CircularProgressIndicator(
          valueColor: AlwaysStoppedAnimation<Color>(
            theme.colorScheme.onPrimary,
          ),
        ),
      ),
    );
  }

  // ============================================================================
  // UTILITAIRES
  // ============================================================================

  /// Construit la décoration d'un champ de texte.
  InputDecoration _buildInputDecoration(
    ThemeData theme,
    String label,
    IconData icon, {
    Widget? suffixIcon,
  }) {
    return InputDecoration(
      labelText: label,
      prefixIcon: Icon(icon, color: theme.colorScheme.onPrimary),
      suffixIcon: suffixIcon,
      filled: true,
      fillColor: theme.colorScheme.onPrimary.withOpacity(0.1),
      border: OutlineInputBorder(
        borderRadius: BorderRadius.circular(12),
        borderSide: BorderSide.none,
      ),
      enabledBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(12),
        borderSide: BorderSide(
          color: theme.colorScheme.onPrimary.withOpacity(0.3),
        ),
      ),
      focusedBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(12),
        borderSide: BorderSide(
          color: theme.colorScheme.onPrimary,
          width: 2,
        ),
      ),
      labelStyle: TextStyle(color: theme.colorScheme.onPrimary),
    );
  }
}