import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import '../models/demo_profile.dart';
import '../models/auth_session.dart';
import '../services/address_repository.dart';
import '../services/auth_repository.dart';
import '../services/local_seed_repository.dart';
import 'address_screen.dart';

final RegExp _lettersOnly = RegExp(r"[a-zA-ZáéíóúÁÉÍÓÚñÑüÜ\s]");
final RegExp _addressText = RegExp(r"[a-zA-Z0-9áéíóúÁÉÍÓÚñÑüÜ#\-\s]");
final RegExp _emailChars = RegExp(r"[a-zA-Z0-9@._+\-]");

class AuthScreen extends StatefulWidget {
  const AuthScreen({
    super.key,
    required this.authRepository,
    required this.addressRepository,
    this.enableLiveFeatures = true,
  });

  final AuthRepository authRepository;
  final AddressRepository addressRepository;
  final bool enableLiveFeatures;

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

class _AuthScreenState extends State<AuthScreen> {
  final GlobalKey<FormState> _loginFormKey = GlobalKey<FormState>();
  final GlobalKey<FormState> _registerFormKey = GlobalKey<FormState>();
  final TextEditingController _loginEmailController = TextEditingController();
  final TextEditingController _loginPasswordController = TextEditingController();
  final TextEditingController _registerNameController = TextEditingController();
  final TextEditingController _registerEmailController = TextEditingController();
  final TextEditingController _registerPasswordController = TextEditingController();
  final TextEditingController _registerConfirmPasswordController = TextEditingController();

  bool _isLoading = false;
  String? _errorMessage;
  LocalSeedData? _seedData;
  bool _loadingSeedData = true;

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

  @override
  void dispose() {
    _loginEmailController.dispose();
    _loginPasswordController.dispose();
    _registerNameController.dispose();
    _registerEmailController.dispose();
    _registerPasswordController.dispose();
    _registerConfirmPasswordController.dispose();
    super.dispose();
  }

  Future<void> _loadSeedData() async {
    final seedData = await LocalSeedRepository.instance.load();
    if (!mounted) {
      return;
    }

    setState(() {
      _seedData = seedData;
      _loadingSeedData = false;
    });
  }

  void _fillDemoProfile(DemoProfile profile) {
    _loginEmailController.text = profile.email;
    _loginPasswordController.text = profile.password;
    _registerNameController.text = profile.name;
    _registerEmailController.text = profile.email;
    _registerPasswordController.text = profile.password;
    _registerConfirmPasswordController.text = profile.password;
  }

  Future<void> _useDemoProfile(DemoProfile profile) async {
    _fillDemoProfile(profile);
    await _submit(() {
      return widget.authRepository.signIn(
        email: profile.email,
        password: profile.password,
      );
    });
  }

  Future<void> _signIn() async {
    if (!(_loginFormKey.currentState?.validate() ?? false)) {
      setState(() {
        _errorMessage = 'Respete los campos';
      });
      return;
    }

    await _submit(() {
      return widget.authRepository.signIn(
        email: _loginEmailController.text.trim(),
        password: _loginPasswordController.text,
      );
    });
  }

  Future<void> _signUp() async {
    if (!(_registerFormKey.currentState?.validate() ?? false)) {
      setState(() {
        _errorMessage = 'Respete los campos';
      });
      return;
    }

    await _submit(() {
      return widget.authRepository.signUp(
        name: _registerNameController.text.trim(),
        email: _registerEmailController.text.trim(),
        password: _registerPasswordController.text,
      );
    });
  }

  Future<void> _submit(Future<AuthSession> Function() action) async {
    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    try {
      final session = await action();
      if (!mounted) {
        return;
      }
      Navigator.of(context).pushReplacement(
        MaterialPageRoute(
          builder: (_) => AddressScreen(
            authRepository: widget.authRepository,
            addressRepository: widget.addressRepository,
            session: session,
            enableLiveFeatures: widget.enableLiveFeatures,
          ),
        ),
      );
    } on AuthException catch (error) {
      if (!mounted) {
        return;
      }
      setState(() {
        _errorMessage = error.message;
      });
    } catch (_) {
      if (!mounted) {
        return;
      }
      setState(() {
        _errorMessage = 'No se pudo completar la operación. Revisa los datos locales y vuelve a intentar.';
      });
    } finally {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        decoration: const BoxDecoration(
          gradient: LinearGradient(
            colors: [Color(0xFF06141B), Color(0xFF0F766E), Color(0xFFE2E8F0)],
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
          ),
        ),
        child: SafeArea(
          child: Center(
            child: SingleChildScrollView(
              padding: const EdgeInsets.all(20),
              child: ConstrainedBox(
                constraints: const BoxConstraints(maxWidth: 440),
                child: Card(
                  elevation: 18,
                  color: Colors.white.withValues(alpha: 0.94),
                  shadowColor: Colors.black26,
                  shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(28)),
                  child: SingleChildScrollView(
                    padding: const EdgeInsets.all(24),
                    child: DefaultTabController(
                      length: 2,
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.stretch,
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          Container(
                            width: 72,
                            height: 72,
                            decoration: BoxDecoration(
                              color: const Color(0xFF0F766E).withValues(alpha: 0.12),
                              borderRadius: BorderRadius.circular(20),
                            ),
                            child: const Icon(Icons.lock_outline, size: 36, color: Color(0xFF0F766E)),
                          ),
                          const SizedBox(height: 20),
                          const Text(
                            'Bienvenido',
                            style: TextStyle(fontSize: 30, fontWeight: FontWeight.w800),
                          ),
                          const SizedBox(height: 8),
                          Text(
                            'Inicia sesión o crea una cuenta para continuar. Luego irás a la pantalla Dirección.',
                            style: TextStyle(color: Colors.grey.shade700, height: 1.4),
                          ),
                          const SizedBox(height: 20),
                          if (!_loadingSeedData && _seedData != null && _seedData!.demoProfiles.isNotEmpty) ...[
                            _DemoProfilesSection(
                              profiles: _seedData!.demoProfiles,
                              onProfileSelected: _useDemoProfile,
                            ),
                            const SizedBox(height: 16),
                          ],
                          Container(
                            decoration: BoxDecoration(
                              color: const Color(0xFFF1F5F9),
                              borderRadius: BorderRadius.circular(16),
                            ),
                            child: TabBar(
                              onTap: (_) {
                                setState(() {
                                  _errorMessage = null;
                                });
                              },
                              indicatorSize: TabBarIndicatorSize.tab,
                              dividerColor: Colors.transparent,
                              indicator: BoxDecoration(
                                color: const Color(0xFF0F766E),
                                borderRadius: BorderRadius.circular(16),
                              ),
                              labelColor: Colors.white,
                              unselectedLabelColor: Colors.grey.shade700,
                              tabs: const [
                                Tab(text: 'Entrar'),
                                Tab(text: 'Crear cuenta'),
                              ],
                            ),
                          ),
                          const SizedBox(height: 20),
                          if (_errorMessage != null) ...[
                            _AuthStatusBanner(message: _errorMessage!),
                            const SizedBox(height: 16),
                          ],
                          SizedBox(
                            height: 200,
                            child: TabBarView(
                              children: [
                                _LoginForm(
                                  formKey: _loginFormKey,
                                  emailController: _loginEmailController,
                                  passwordController: _loginPasswordController,
                                  onSubmit: _signIn,
                                  isLoading: _isLoading,
                                ),
                                _RegisterForm(
                                  formKey: _registerFormKey,
                                  nameController: _registerNameController,
                                  emailController: _registerEmailController,
                                  passwordController: _registerPasswordController,
                                  confirmPasswordController: _registerConfirmPasswordController,
                                  onSubmit: _signUp,
                                  isLoading: _isLoading,
                                ),
                              ],
                            ),
                          ),
                          const SizedBox(height: 12),
                        ],
                      ),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _LoginForm extends StatelessWidget {
  const _LoginForm({
    required this.formKey,
    required this.emailController,
    required this.passwordController,
    required this.onSubmit,
    required this.isLoading,
  });

  final GlobalKey<FormState> formKey;
  final TextEditingController emailController;
  final TextEditingController passwordController;
  final Future<void> Function() onSubmit;
  final bool isLoading;

  @override
  Widget build(BuildContext context) {
    return Form(
      key: formKey,
      child: Column(
        children: [
          TextFormField(
            controller: emailController,
            keyboardType: TextInputType.emailAddress,
            inputFormatters: [FilteringTextInputFormatter.allow(_emailChars)],
            decoration: const InputDecoration(
              labelText: 'Correo electrónico',
              prefixIcon: Icon(Icons.email_outlined),
              border: OutlineInputBorder(),
            ),
            validator: (value) {
              if (value == null || value.trim().isEmpty) {
                return 'Ingresa tu correo';
              }
              if (!value.contains('@') || value.startsWith('@') || value.endsWith('@')) {
                return 'Ingresa un correo válido';
              }
              return null;
            },
          ),
          const SizedBox(height: 16),
          TextFormField(
            controller: passwordController,
            obscureText: true,
            decoration: const InputDecoration(
              labelText: 'Contraseña',
              prefixIcon: Icon(Icons.lock_outline),
              border: OutlineInputBorder(),
            ),
            validator: (value) {
              if (value == null || value.isEmpty) {
                return 'Ingresa tu contraseña';
              }
              if (value.length < 6) {
                return 'Usa al menos 6 caracteres';
              }
              return null;
            },
          ),
          const SizedBox(height: 20),
          SizedBox(
            width: double.infinity,
            height: 52,
            child: FilledButton(
              onPressed: isLoading ? null : onSubmit,
              child: isLoading
                  ? const SizedBox(
                      width: 22,
                      height: 22,
                      child: CircularProgressIndicator(strokeWidth: 2.2, color: Colors.white),
                    )
                  : const Text('Ingresar'),
            ),
          ),
        ],
      ),
    );
  }
}

class _RegisterForm extends StatelessWidget {
  const _RegisterForm({
    required this.formKey,
    required this.nameController,
    required this.emailController,
    required this.passwordController,
    required this.confirmPasswordController,
    required this.onSubmit,
    required this.isLoading,
  });

  final GlobalKey<FormState> formKey;
  final TextEditingController nameController;
  final TextEditingController emailController;
  final TextEditingController passwordController;
  final TextEditingController confirmPasswordController;
  final Future<void> Function() onSubmit;
  final bool isLoading;

  @override
  Widget build(BuildContext context) {
    return Form(
      key: formKey,
      child: ListView(
        children: [
          TextFormField(
            controller: nameController,
            textCapitalization: TextCapitalization.words,
            keyboardType: TextInputType.name,
            inputFormatters: [FilteringTextInputFormatter.allow(_lettersOnly)],
            decoration: const InputDecoration(
              labelText: 'Nombre',
              prefixIcon: Icon(Icons.person_outline),
              border: OutlineInputBorder(),
            ),
            validator: (value) {
              if (value == null || value.trim().isEmpty) {
                return 'Ingresa tu nombre';
              }
              return null;
            },
          ),
          const SizedBox(height: 16),
          TextFormField(
            controller: emailController,
            keyboardType: TextInputType.emailAddress,
            inputFormatters: [FilteringTextInputFormatter.allow(_emailChars)],
            decoration: const InputDecoration(
              labelText: 'Correo electrónico',
              prefixIcon: Icon(Icons.email_outlined),
              border: OutlineInputBorder(),
            ),
            validator: (value) {
              if (value == null || value.trim().isEmpty) {
                return 'Ingresa tu correo';
              }
              if (!value.contains('@') || value.startsWith('@') || value.endsWith('@')) {
                return 'Ingresa un correo válido';
              }
              return null;
            },
          ),
          const SizedBox(height: 16),
          TextFormField(
            controller: passwordController,
            obscureText: true,
            inputFormatters: [FilteringTextInputFormatter.deny(RegExp(r'\s'))],
            decoration: const InputDecoration(
              labelText: 'Contraseña',
              prefixIcon: Icon(Icons.lock_outline),
              border: OutlineInputBorder(),
            ),
            validator: (value) {
              if (value == null || value.isEmpty) {
                return 'Ingresa una contraseña';
              }
              if (value.length < 6) {
                return 'Usa al menos 6 caracteres';
              }
              return null;
            },
          ),
          const SizedBox(height: 16),
          TextFormField(
            controller: confirmPasswordController,
            obscureText: true,
            inputFormatters: [FilteringTextInputFormatter.deny(RegExp(r'\s'))],
            decoration: const InputDecoration(
              labelText: 'Confirmar contraseña',
              prefixIcon: Icon(Icons.lock_reset_outlined),
              border: OutlineInputBorder(),
            ),
            validator: (value) {
              if (value == null || value.isEmpty) {
                return 'Confirma tu contraseña';
              }
              if (value != passwordController.text) {
                return 'Las contraseñas no coinciden';
              }
              return null;
            },
          ),
          const SizedBox(height: 20),
          SizedBox(
            width: double.infinity,
            height: 52,
            child: FilledButton(
              onPressed: isLoading ? null : onSubmit,
              child: isLoading
                  ? const SizedBox(
                      width: 22,
                      height: 22,
                      child: CircularProgressIndicator(strokeWidth: 2.2, color: Colors.white),
                    )
                  : const Text('Registrarme'),
            ),
          ),
        ],
      ),
    );
  }
}

class _AuthStatusBanner extends StatelessWidget {
  const _AuthStatusBanner({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: const Color(0xFFFEE2E2),
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: const Color(0xFFFCA5A5)),
      ),
      child: Text(
        message,
        style: const TextStyle(color: Color(0xFF991B1B), height: 1.35),
      ),
    );
  }
}

class _DemoProfilesSection extends StatelessWidget {
  const _DemoProfilesSection({
    required this.profiles,
    required this.onProfileSelected,
  });

  final List<DemoProfile> profiles;
  final Future<void> Function(DemoProfile profile) onProfileSelected;

  @override
  Widget build(BuildContext context) {
    return Card(
      elevation: 2,
      color: const Color(0xFFF8FAFC),
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('Perfiles demo', style: Theme.of(context).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w800)),
            const SizedBox(height: 8),
            Text('Toca un perfil para llenar el formulario de acceso.', style: TextStyle(color: Colors.grey.shade700)),
            const SizedBox(height: 12),
            Wrap(
              spacing: 8,
              runSpacing: 8,
              children: profiles
                  .map(
                    (profile) => ActionChip(
                      label: Text('${profile.name} • ${profile.routeId}'),
                      onPressed: () => onProfileSelected(profile),
                    ),
                  )
                  .toList(growable: false),
            ),
          ],
        ),
      ),
    );
  }
}