import 'dart:async';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:url_launcher/url_launcher.dart';
import 'package:go_router/go_router.dart';
import 'package:p_tits_pas/services/bug_report_service.dart';
import '../../widgets/image_button.dart';
import '../../widgets/custom_app_text_field.dart';
import '../../services/auth_service.dart';
import '../../widgets/auth/change_password_dialog.dart';

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

  @override
  State<LoginScreen> createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginScreen> with WidgetsBindingObserver {
  final _formKey = GlobalKey<FormState>();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  
  bool _isLoading = false;
  String? _errorMessage;

  static const double _mobileBreakpoint = 900.0;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _emailController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  @override
  void didChangeMetrics() {
    super.didChangeMetrics();
    if (mounted) setState(() {});
  }

  String? _validateEmail(String? value) {
    if (value == null || value.isEmpty) {
      return 'Veuillez entrer votre email';
    }
    if (!RegExp(r'^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$').hasMatch(value)) {
      return 'Veuillez entrer un email valide';
    }
    return null;
  }

  String? _validatePassword(String? value) {
    if (value == null || value.isEmpty) {
      return 'Veuillez entrer votre mot de passe';
    }
    return null;
  }

  /// Gère la connexion de l'utilisateur
  Future<void> _handleLogin() async {
    // Réinitialiser le message d'erreur
    setState(() {
      _errorMessage = null;
    });

    if (!(_formKey.currentState?.validate() ?? false)) {
      return;
    }

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

    try {
      // Appeler le service d'authentification
      final user = await AuthService.login(
        _emailController.text.trim(),
        _passwordController.text,
      );

      if (!mounted) return;

      // Vérifier si l'utilisateur doit changer son mot de passe
      if (user.changementMdpObligatoire) {
        if (!mounted) return;
        
        // Afficher la modale de changement de mot de passe (non-dismissible)
        final result = await showDialog<bool>(
          context: context,
          barrierDismissible: false,
          builder: (context) => const ChangePasswordDialog(),
        );

        // Si le changement de mot de passe a réussi, rafraîchir l'utilisateur
        if (result == true && mounted) {
          await AuthService.refreshCurrentUser();
        }
      }

      if (!mounted) return;

      // Rediriger selon le rôle de l'utilisateur
      _redirectUserByRole(user.role);
    } catch (e) {
      setState(() {
        _isLoading = false;
        _errorMessage = e.toString().replaceAll('Exception: ', '');
      });
    }
  }

  /// Redirige l'utilisateur selon son rôle
  void _redirectUserByRole(String role) {
    switch (role.toLowerCase()) {
      case 'super_admin':
      case 'gestionnaire':
        Navigator.pushReplacementNamed(context, '/admin-dashboard');
        break;
      case 'parent':
        Navigator.pushReplacementNamed(context, '/parent-dashboard');
        break;
      case 'assistante_maternelle':
        Navigator.pushReplacementNamed(context, '/am-dashboard');
        break;
      default:
        Navigator.pushReplacementNamed(context, '/home');
    }
  }

  @override
  Widget build(BuildContext context) {
    final isMobile = MediaQuery.of(context).size.width < _mobileBreakpoint;
    if (isMobile) {
      return Scaffold(
        backgroundColor: Colors.transparent,
        body: _buildMobileLayout(context),
      );
    }
    return Scaffold(
      backgroundColor: Colors.transparent,
      body: LayoutBuilder(
        builder: (context, constraints) {
          final w = constraints.maxWidth;
          final h = constraints.maxHeight;
          return FutureBuilder(
              future: _getImageDimensions(),
              builder: (context, snapshot) {
                if (!snapshot.hasData) {
                  return const Center(child: CircularProgressIndicator());
                }

                final imageDimensions = snapshot.data!;
                final imageHeight = h;
                final imageWidth = imageHeight * (imageDimensions.width / imageDimensions.height);
                final remainingWidth = w - imageWidth;
                final leftMargin = remainingWidth / 4;

                return Stack(
                  children: [
                    // Fond en papier
                    Positioned.fill(
                      child: Image.asset(
                        'assets/images/paper2.png',
                        fit: BoxFit.cover,
                        repeat: ImageRepeat.repeat,
                      ),
                    ),
                    // Image principale
                    Positioned(
                      left: leftMargin,
                      top: 0,
                      height: imageHeight,
                      width: imageWidth,
                      child: Image.asset(
                        'assets/images/river_logo_desktop.png',
                        fit: BoxFit.contain,
                      ),
                    ),
                    // Formulaire dans le cadran en bas à droite
                    Positioned(
                      right: 0,
                      bottom: 0,
                      width: w * 0.6,  // 60% de la largeur de l'écran
                      height: h * 0.5,  // 50% de la hauteur de l'écran
                      child: Padding(
                        padding: EdgeInsets.all(w * 0.02),  // 2% de padding
                        child: Form(
                          key: _formKey,
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.stretch,
                            children: [
                              // Champs côte à côte
                              Row(
                                crossAxisAlignment: CrossAxisAlignment.start,
                                children: [
                                  Expanded(
                                    child: CustomAppTextField(
                                      controller: _emailController,
                                      labelText: 'Email',
                                      hintText: 'Votre adresse email',
                                      validator: _validateEmail,
                                      style: CustomAppTextFieldStyle.lavande,
                                      fieldHeight: 53,
                                      fieldWidth: double.infinity,
                                    ),
                                  ),
                                  const SizedBox(width: 20),
                                  Expanded(
                                    child: CustomAppTextField(
                                      controller: _passwordController,
                                      labelText: 'Mot de passe',
                                      hintText: 'Votre mot de passe',
                                      obscureText: true,
                                      validator: _validatePassword,
                                      style: CustomAppTextFieldStyle.jaune,
                                      fieldHeight: 53,
                                      fieldWidth: double.infinity,
                                    ),
                                  ),
                                ],
                              ),
                              const SizedBox(height: 20),
                              
                              // Message d'erreur
                              if (_errorMessage != null)
                                Container(
                                  padding: const EdgeInsets.all(12),
                                  margin: const EdgeInsets.only(bottom: 15),
                                  decoration: BoxDecoration(
                                    color: Colors.red[50],
                                    borderRadius: BorderRadius.circular(10),
                                    border: Border.all(color: Colors.red[300]!),
                                  ),
                                  child: Row(
                                    children: [
                                      Icon(Icons.error_outline, color: Colors.red[700], size: 20),
                                      const SizedBox(width: 10),
                                      Expanded(
                                        child: Text(
                                          _errorMessage!,
                                          style: GoogleFonts.merienda(
                                            fontSize: 12,
                                            color: Colors.red[700],
                                          ),
                                        ),
                                      ),
                                    ],
                                  ),
                                ),
                              
                              // Bouton centré
                              Center(
                                child: _isLoading
                                    ? const CircularProgressIndicator()
                                    : ImageButton(
                                        bg: 'assets/images/bg_green.png',
                                        width: 300,
                                        height: 40,
                                        text: 'Se connecter',
                                        textColor: const Color(0xFF2D6A4F),
                                        onPressed: _handleLogin,
                                      ),
                              ),
                              const SizedBox(height: 10),
                              // Lien mot de passe oublié
                              Center(
                                child: TextButton(
                                  onPressed: () {
                                    // TODO: Implémenter la logique de récupération de mot de passe
                                  },
                                  child: Text(
                                    'Mot de passe oublié ?',
                                    style: GoogleFonts.merienda(
                                      fontSize: 14,
                                      color: const Color(0xFF2D6A4F),
                                      decoration: TextDecoration.underline,
                                    ),
                                  ),
                                ),
                              ),
                              const SizedBox(height: 20),
                              // Lien de création de compte (version originale)
                              Center(
                                child: TextButton(
                                  onPressed: () {
                                    context.go('/register-choice');
                                  },
                                  child: Text(
                                    'Créer un compte',
                                    style: GoogleFonts.merienda(
                                      fontSize: 16,
                                      color: const Color(0xFF2D6A4F),
                                      decoration: TextDecoration.underline,
                                    ),
                                  ),
                                ),
                              ),
                            ],
                          ),
                        ),
                      ),
                    ),
                    // Pied de page (Wrap pour éviter overflow sur petite largeur)
                    Positioned(
                      left: 0,
                      right: 0,
                      bottom: 0,
                      child: Container(
                        padding: const EdgeInsets.symmetric(vertical: 8.0),
                        decoration: const BoxDecoration(
                          color: Colors.transparent,
                        ),
                        child: Wrap(
                          alignment: WrapAlignment.center,
                          runSpacing: 8,
                          children: [
                            _FooterLink(
                              text: 'Contact support',
                              onTap: () async {
                                final Uri emailLaunchUri = Uri(
                                  scheme: 'mailto',
                                  path: 'support@supernounou.local',
                                );
                                if (await canLaunchUrl(emailLaunchUri)) {
                                  await launchUrl(emailLaunchUri);
                                } else {
                                  ScaffoldMessenger.of(context).showSnackBar(
                                    SnackBar(
                                      content: Text(
                                        'Impossible d\'ouvrir le client mail',
                                        style: GoogleFonts.merienda(),
                                      ),
                                    ),
                                  );
                                }
                              },
                            ),
                            _FooterLink(
                              text: 'Signaler un bug',
                              onTap: () {
                                _showBugReportDialog(context);
                              },
                            ),
                            _FooterLink(
                              text: 'Mentions légales',
                              onTap: () {
                                context.go('/legal');
                              },
                            ),
                            _FooterLink(
                              text: 'Politique de confidentialité',
                              onTap: () {
                                context.go('/privacy');
                              },
                            ),
                          ],
                        ),
                      ),
                    ),
                  ],
                );
              },
            );
        },
      ),
    );
  }

  /// Dimensions de river_logo_mobile.png (à mettre à jour si l'asset change).
  static const int _riverLogoMobileWidth = 600;
  static const int _riverLogoMobileHeight = 1080;
  /// Fraction de la hauteur de l'image où se termine visuellement le slogan (0 = haut, 1 = bas).
  static const double _sloganEndFraction = 0.42;
  static const double _gapBelowSlogan = 12.0;

  Widget _buildMobileLayout(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        final h = constraints.maxHeight;
        final w = constraints.maxWidth;
        final imageAspectRatio = _riverLogoMobileHeight / _riverLogoMobileWidth;
        final formTop = w * imageAspectRatio * _sloganEndFraction + _gapBelowSlogan;
        return Stack(
          clipBehavior: Clip.none,
          children: [
            Positioned.fill(
              child: Image.asset(
                'assets/images/paper2.png',
                fit: BoxFit.cover,
                repeat: ImageRepeat.repeat,
              ),
            ),
            Positioned(
              top: 0,
              left: 0,
              right: 0,
              height: h * 1.2,
              child: OverflowBox(
                alignment: Alignment.topCenter,
                minWidth: w,
                maxWidth: w,
                minHeight: 0,
                maxHeight: h * 2.5,
                child: Image.asset(
                  'assets/images/river_logo_mobile.png',
                  width: w,
                  fit: BoxFit.fitWidth,
                ),
              ),
            ),
            Positioned(
              top: formTop,
              left: 0,
              right: 0,
              bottom: 0,
              child: SafeArea(
                top: false,
                child: Column(
                  children: [
                    Expanded(
                      child: SingleChildScrollView(
                        padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 20),
                        child: ConstrainedBox(
                          constraints: const BoxConstraints(maxWidth: 400),
                          child: Form(
                            key: _formKey,
                            child: Column(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                      const SizedBox(height: 16),
                      CustomAppTextField(
                        controller: _emailController,
                        labelText: 'Email',
                        showLabel: false,
                        hintText: 'Votre adresse email',
                        validator: _validateEmail,
                        style: CustomAppTextFieldStyle.lavande,
                        fieldHeight: 48,
                        fieldWidth: double.infinity,
                      ),
                      const SizedBox(height: 12),
                      CustomAppTextField(
                        controller: _passwordController,
                        labelText: 'Mot de passe',
                        showLabel: false,
                        hintText: 'Votre mot de passe',
                        obscureText: true,
                        validator: _validatePassword,
                        style: CustomAppTextFieldStyle.jaune,
                        fieldHeight: 48,
                        fieldWidth: double.infinity,
                      ),
                      if (_errorMessage != null) ...[
                        const SizedBox(height: 12),
                        Container(
                          padding: const EdgeInsets.all(12),
                          decoration: BoxDecoration(
                            color: Colors.red.shade50,
                            borderRadius: BorderRadius.circular(10),
                            border: Border.all(color: Colors.red.shade300),
                          ),
                          child: Row(
                            children: [
                              Icon(Icons.error_outline, color: Colors.red.shade700, size: 20),
                              const SizedBox(width: 10),
                              Expanded(
                                child: Text(
                                  _errorMessage!,
                                  style: GoogleFonts.merienda(fontSize: 12, color: Colors.red.shade700),
                                ),
                              ),
                            ],
                          ),
                        ),
                      ],
                      const SizedBox(height: 12),
                      _isLoading
                          ? const CircularProgressIndicator()
                          : ImageButton(
                              bg: 'assets/images/bg_green.png',
                              width: double.infinity,
                              height: 44,
                              text: 'Se connecter',
                              textColor: const Color(0xFF2D6A4F),
                              onPressed: _handleLogin,
                            ),
                      const SizedBox(height: 12),
                      TextButton(
                        onPressed: () { /* TODO */ },
                        child: Text(
                          'Mot de passe oublié ?',
                          style: GoogleFonts.merienda(
                            fontSize: 14,
                            color: const Color(0xFF2D6A4F),
                            decoration: TextDecoration.underline,
                          ),
                        ),
                      ),
                      TextButton(
                        onPressed: () => context.go('/register-choice'),
                        child: Text(
                          'Créer un compte',
                          style: GoogleFonts.merienda(
                            fontSize: 16,
                            color: const Color(0xFF2D6A4F),
                            decoration: TextDecoration.underline,
                          ),
                        ),
                      ),
                    ],
                            ),
                          ),
                        ),
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.only(bottom: 12, top: 8),
                      child: Wrap(
                        alignment: WrapAlignment.center,
                        runSpacing: 6,
                        spacing: 4,
                        children: [
                          _FooterLink(
                            text: 'Contact support',
                            fontSize: 11,
                            onTap: () async {
                              final uri = Uri(scheme: 'mailto', path: 'support@supernounou.local');
                              if (await canLaunchUrl(uri)) {
                                await launchUrl(uri);
                              } else if (context.mounted) {
                                ScaffoldMessenger.of(context).showSnackBar(
                                  SnackBar(content: Text('Impossible d\'ouvrir le client mail', style: GoogleFonts.merienda())),
                                );
                              }
                            },
                          ),
                          _FooterLink(
                            text: 'Signaler un bug',
                            fontSize: 11,
                            onTap: () => _showBugReportDialog(context),
                          ),
                          _FooterLink(
                            text: 'Mentions légales',
                            fontSize: 11,
                            onTap: () => context.go('/legal'),
                          ),
                          _FooterLink(
                            text: 'Politique de confidentialité',
                            fontSize: 11,
                            onTap: () => context.go('/privacy'),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        );
      },
    );
  }

  void _showBugReportDialog(BuildContext context) {
    final TextEditingController controller = TextEditingController();

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(
          'Signaler un bug',
          style: GoogleFonts.merienda(),
        ),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            TextField(
              controller: controller,
              maxLines: 5,
              decoration: InputDecoration(
                hintText: 'Décrivez le problème rencontré...',
                border: OutlineInputBorder(
                  borderRadius: BorderRadius.circular(10),
                ),
              ),
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: Text(
              'Annuler',
              style: GoogleFonts.merienda(),
            ),
          ),
          TextButton(
            onPressed: () async {
              if (controller.text.trim().isEmpty) {
                ScaffoldMessenger.of(context).showSnackBar(
                  SnackBar(
                    content: Text(
                      'Veuillez décrire le problème',
                      style: GoogleFonts.merienda(),
                    ),
                  ),
                );
                return;
              }

              try {
                await BugReportService.sendReport(controller.text);
                if (context.mounted) {
                  Navigator.pop(context);
                  ScaffoldMessenger.of(context).showSnackBar(
                    SnackBar(
                      content: Text(
                        'Rapport envoyé avec succès',
                        style: GoogleFonts.merienda(),
                      ),
                    ),
                  );
                }
              } catch (e) {
                if (context.mounted) {
                  ScaffoldMessenger.of(context).showSnackBar(
                    SnackBar(
                      content: Text(
                        'Erreur lors de l\'envoi du rapport',
                        style: GoogleFonts.merienda(),
                      ),
                    ),
                  );
                }
              }
            },
            child: Text(
              'Envoyer',
              style: GoogleFonts.merienda(),
            ),
          ),
        ],
      ),
    );
  }

  Future<ImageDimensions> _getImageDimensions() async {
    final image = Image.asset('assets/images/river_logo_desktop.png');
    final completer = Completer<ImageDimensions>();
    image.image.resolve(const ImageConfiguration()).addListener(
      ImageStreamListener((info, _) {
        completer.complete(ImageDimensions(
          width: info.image.width.toDouble(),
          height: info.image.height.toDouble(),
        ));
      }),
    );
    return completer.future;
  }
}

class ImageDimensions {
  final double width;
  final double height;

  ImageDimensions({required this.width, required this.height});
}

// ───────────────────────────────────────────────────────────────
// Lien du pied de page
// ───────────────────────────────────────────────────────────────
class _FooterLink extends StatelessWidget {
  final String text;
  final VoidCallback onTap;
  final double fontSize;

  const _FooterLink({
    required this.text,
    required this.onTap,
    this.fontSize = 14.0,
  });

  @override
  Widget build(BuildContext context) {
    return InkWell(
      onTap: onTap,
      child: Padding(
        padding: EdgeInsets.symmetric(horizontal: fontSize > 12 ? 8.0 : 4.0),
        child: Text(
          text,
          style: GoogleFonts.merienda(
            fontSize: fontSize,
            color: Colors.black87,
            decoration: TextDecoration.underline,
          ),
        ),
      ),
    );
  }
}