import 'package:sysfarma_mobile/src/core/models/tenant_session.dart';
import 'package:sysfarma_mobile/src/core/notifications/push_notification_service.dart';
import 'package:sysfarma_mobile/src/core/network/api_client.dart';
import 'package:sysfarma_mobile/src/core/storage/tenant_session_store.dart';
import 'package:sysfarma_mobile/src/core/theme/app_tokens.dart';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

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

  @override
  ConsumerState<LoginScreen> createState() => _LoginScreenState();
}

class _LoginScreenState extends ConsumerState<LoginScreen> {
  final _formKey = GlobalKey<FormState>();
  final _rucController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();

  bool _isSubmitting = false;
  bool _obscurePassword = true;
  bool _showRucStep = true;

  String? _resolvedBaseUrl;
  String? _resolvedCompanyName;

  @override
  void initState() {
    super.initState();
    _hydrateStoredSession();
    WidgetsBinding.instance.addPostFrameCallback((_) => _debugAutoLogin());
  }

  @override
  void dispose() {
    _rucController.dispose();
    _emailController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  Future<void> _hydrateStoredSession() async {
    final store = ref.read(tenantSessionStoreProvider);
    final tenant = await store.readTenantConfig();
    if (!mounted) return;

    if (tenant.ruc != null && tenant.baseUrl != null) {
      _rucController.text = tenant.ruc!;
      _resolvedBaseUrl = tenant.baseUrl;
      _resolvedCompanyName = tenant.companyName;
      _emailController.clear();
      _passwordController.clear();
      setState(() {
        _showRucStep = false;
      });
    }
  }

  Future<void> _debugAutoLogin() async {
    const autoLogin =
        bool.fromEnvironment('MOBILE_WEB_AUTO_LOGIN', defaultValue: false);
    const testMode =
        bool.fromEnvironment('MOBILE_WEB_TEST_MODE', defaultValue: false);
    if (!kIsWeb || !autoLogin) return;
    if (_isSubmitting) return;

    const baseUrl =
        String.fromEnvironment('MOBILE_WEB_BASE_URL', defaultValue: '');
    const email =
        String.fromEnvironment('MOBILE_WEB_EMAIL', defaultValue: '');
    const password =
        String.fromEnvironment('MOBILE_WEB_PASSWORD', defaultValue: '');
    const ruc =
        String.fromEnvironment('MOBILE_WEB_RUC', defaultValue: '');
    const companyName =
        String.fromEnvironment('MOBILE_WEB_COMPANY', defaultValue: '');

    if (baseUrl.isEmpty || email.isEmpty || password.isEmpty) return;
    if (testMode && !mounted) return;

    _resolvedBaseUrl = baseUrl;
    _resolvedCompanyName =
        companyName.isNotEmpty ? companyName : _resolvedCompanyName;
    if (ruc.isNotEmpty) {
      _rucController.text = ruc;
    }

    setState(() {
      _showRucStep = false;
      _isSubmitting = true;
    });

    final apiClient = ref.read(apiClientProvider);
    final sessionStore = ref.read(tenantSessionStoreProvider);

    final login = await apiClient.login(
      baseUrl: baseUrl,
      email: email,
      password: password,
    );

    if (!mounted) return;

    if (!login.success) {
      _showMessage(login.message ?? 'No se pudo iniciar sesion.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    final data = login.data ?? const <String, dynamic>{};
    final company =
        Map<String, dynamic>.from(data['company'] as Map? ?? const {});
    final token = data['token']?.toString();

    if (token == null || token.isEmpty) {
      _showMessage('El API no devolvio un token valido.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    final resolvedCompanyName = _resolvedCompanyName ??
        company['trade_name']?.toString() ??
        company['name']?.toString();
    final userMap =
        Map<String, dynamic>.from(data['user'] as Map? ?? const {});
    final userType = userMap['type']?.toString();
    final activeEstablishmentId = int.tryParse(
      '${data['active_establishment_id'] ?? userMap['active_establishment_id'] ?? userMap['establishment_id'] ?? ''}',
    );

    await sessionStore.saveSession(
      TenantSession(
        baseUrl: ApiClient.normalizeBaseUrl(baseUrl),
        token: token,
        companyName: resolvedCompanyName,
        ruc: ruc.isNotEmpty ? ruc : null,
        userType: userType,
        activeEstablishmentId: activeEstablishmentId,
      ),
    );
    ref.invalidate(currentSessionProvider);

    if (!mounted) return;

    setState(() => _isSubmitting = false);
    context.go('/home');
  }

  Future<void> _resolveRuc() async {
    final ruc = _rucController.text.trim();
    if (ruc.isEmpty) return;

    if (ruc.length != 11) {
      _showMessage('El RUC debe tener 11 digitos.', isError: true);
      return;
    }

    setState(() => _isSubmitting = true);

    final api = ref.read(apiClientProvider);

    // Try resolving on last known URL, or fall back to discovery URL
    String? discoveryUrl = _resolvedBaseUrl;
    if (discoveryUrl == null || discoveryUrl.isEmpty) {
      final session = await ref.read(tenantSessionStoreProvider).readSession();
      discoveryUrl = session?.baseUrl;
    }
    discoveryUrl ??= ApiClient.defaultDiscoveryUrl;
    if (discoveryUrl.contains('enterfarmaplus.test')) {
      discoveryUrl = 'https://demo.sysfarma.pe';
    }

    final response = await api.resolveRuc(
      ruc: ruc,
      baseUrl: discoveryUrl,
    );

    if (!mounted) return;

    if (!response.success) {
      _showMessage(response.message ?? 'No se encontro la empresa.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    final data = response.data ?? {};
    _resolvedBaseUrl = data['base_url']?.toString();
    _resolvedCompanyName = data['company_name']?.toString();

    if (_resolvedBaseUrl == null || _resolvedBaseUrl!.isEmpty) {
      _showMessage('No se obtuvo la URL de la empresa.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    // Validate with bootstrap
    final bootstrap = await api.bootstrap(baseUrl: _resolvedBaseUrl);
    if (!mounted) return;

    if (!bootstrap.success) {
      _showMessage(bootstrap.message ?? 'No se pudo conectar con la empresa.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    _emailController.clear();
    _passwordController.clear();
    setState(() {
      _isSubmitting = false;
      _showRucStep = false;
    });
  }

  Future<void> _submit() async {
    final isValid = _formKey.currentState?.validate() ?? false;
    if (!isValid || _isSubmitting) return;

    if (_resolvedBaseUrl == null || _resolvedBaseUrl!.isEmpty) {
      _showMessage('Primero debes conectar tu empresa con el RUC.', isError: true);
      return;
    }

    setState(() => _isSubmitting = true);

    final apiClient = ref.read(apiClientProvider);
    final sessionStore = ref.read(tenantSessionStoreProvider);

    final login = await apiClient.login(
      baseUrl: _resolvedBaseUrl!,
      email: _emailController.text.trim(),
      password: _passwordController.text,
    );

    if (!mounted) return;

    if (!login.success) {
      _showMessage(login.message ?? 'No se pudo iniciar sesion.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    final data = login.data ?? const <String, dynamic>{};
    final company =
        Map<String, dynamic>.from(data['company'] as Map? ?? const {});
    final token = data['token']?.toString();

    if (token == null || token.isEmpty) {
      _showMessage('El API no devolvio un token valido.', isError: true);
      setState(() => _isSubmitting = false);
      return;
    }

    final companyName = _resolvedCompanyName ??
        company['trade_name']?.toString() ??
        company['name']?.toString();
    final userMap =
        Map<String, dynamic>.from(data['user'] as Map? ?? const {});
    final userType = userMap['type']?.toString();
    final activeEstablishmentId = int.tryParse(
      '${data['active_establishment_id'] ?? userMap['active_establishment_id'] ?? userMap['establishment_id'] ?? ''}',
    );

    await sessionStore.saveSession(
      TenantSession(
        baseUrl: ApiClient.normalizeBaseUrl(_resolvedBaseUrl!),
        token: token,
        companyName: companyName,
        ruc: _rucController.text.trim(),
        userType: userType,
        activeEstablishmentId: activeEstablishmentId,
      ),
    );

    await ref.read(pushNotificationServiceProvider).registerCurrentToken();
    ref.invalidate(currentSessionProvider);

    if (!mounted) return;

    setState(() => _isSubmitting = false);
    context.go('/home');
  }

  void _showMessage(String message, {bool isError = false}) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message),
        backgroundColor: isError ? const Color(0xFFDC2626) : null,
      ),
    );
  }

  void _showTenantGuide() {
    showModalBottomSheet<void>(
      context: context,
      builder: (context) {
        return SafeArea(
          child: SingleChildScrollView(
            padding: const EdgeInsets.fromLTRB(20, 8, 20, 24),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text('Como conectar tu empresa',
                    style: Theme.of(context).textTheme.headlineSmall),
                const SizedBox(height: 12),
                Text(
                  'Ingresa el RUC (numero de 11 digitos) de tu empresa. La app se conectara automaticamente con tu cuenta.',
                  style: Theme.of(context)
                      .textTheme
                      .bodyMedium
                      ?.copyWith(color: AppTokens.secondary),
                ),
                const SizedBox(height: 18),
                const _LoginHintRow(
                  icon: Icons.business_rounded,
                  title: 'RUC de empresa',
                  subtitle: 'Ejemplo: 20100130204 (11 digitos)',
                ),
                const SizedBox(height: 12),
                const _LoginHintRow(
                  icon: Icons.alternate_email_rounded,
                  title: 'Usuario actual',
                  subtitle: 'Se reutiliza el mismo correo del panel web.',
                ),
                const SizedBox(height: 12),
                const _LoginHintRow(
                  icon: Icons.verified_user_rounded,
                  title: 'Sesion segura',
                  subtitle:
                      'El token se guarda en almacenamiento seguro del dispositivo.',
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          // Fondo con gradiente de marca
          const Positioned.fill(
            child: DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topLeft,
                  end: Alignment.bottomRight,
                  colors: [
                    Color(0xFFF3FFE8),
                    Color(0xFFF5F6FF),
                    Color(0xFFEEF0FF),
                  ],
                ),
              ),
            ),
          ),
          // Círculos decorativos
          Positioned(
            top: -60,
            left: -40,
            child: Container(
              width: 220,
              height: 220,
              decoration: BoxDecoration(
                color: const Color(0xFF7BC043).withValues(alpha: 0.18),
                shape: BoxShape.circle,
              ),
            ),
          ),
          Positioned(
            bottom: -80,
            right: -60,
            child: Container(
              width: 280,
              height: 280,
              decoration: BoxDecoration(
                color: const Color(0xFF5F6CFB).withValues(alpha: 0.16),
                shape: BoxShape.circle,
              ),
            ),
          ),
          // Contenido
          SafeArea(
            child: Center(
              child: SingleChildScrollView(
                padding: const EdgeInsets.all(24),
                child: ConstrainedBox(
                  constraints: const BoxConstraints(maxWidth: 460),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      const _LoginBrandHeader(),
                      const SizedBox(height: 28),
                      _showRucStep ? _buildRucCard() : _buildCredentialsCard(),
                      const SizedBox(height: 18),
                      Center(
                        child: Text(
                          'v0.1.0 · SysFarma © 2026',
                          style: Theme.of(context)
                              .textTheme
                              .labelSmall
                              ?.copyWith(color: AppTokens.secondary),
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildRucCard() {
    const testMode =
        bool.fromEnvironment('MOBILE_WEB_TEST_MODE', defaultValue: false);
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Form(
          key: _formKey,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              if (kIsWeb && testMode) ...[
                Align(
                  alignment: Alignment.centerRight,
                  child: TextButton.icon(
                    onPressed: _isSubmitting ? null : _debugAutoLogin,
                    icon: const Icon(Icons.play_circle_fill_rounded),
                    label: const Text('Entrar demo'),
                  ),
                ),
                const SizedBox(height: 8),
              ],
              Text(
                'Conectar empresa',
                style: Theme.of(context).textTheme.titleLarge,
              ),
              const SizedBox(height: 8),
              Text(
                'Ingresa el RUC de tu negocio para conectar.',
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: AppTokens.secondary,
                    ),
              ),
              const SizedBox(height: 6),
              Align(
                alignment: Alignment.centerLeft,
                child: TextButton.icon(
                  onPressed: _showTenantGuide,
                  icon: const Icon(Icons.help_outline_rounded),
                  label: const Text('Ayuda'),
                ),
              ),
              const SizedBox(height: 20),
              TextFormField(
                controller: _rucController,
                keyboardType: TextInputType.number,
                maxLength: 11,
                key: const ValueKey('ruc_field'),
                inputFormatters: [FilteringTextInputFormatter.digitsOnly],
                decoration: const InputDecoration(
                  labelText: 'RUC',
                  hintText: '20100130204',
                  prefixIcon: Icon(Icons.business_rounded),
                  counterText: '',
                ),
                validator: (value) {
                  if (value == null || value.trim().isEmpty) {
                    return 'Ingresa el RUC de la empresa.';
                  }
                  if (value.trim().length != 11) {
                    return 'El RUC debe tener 11 digitos.';
                  }
                  return null;
                },
                onFieldSubmitted: (_) => _resolveRuc(),
              ),
              const SizedBox(height: 22),
              FilledButton.icon(
                onPressed: _isSubmitting ? null : _resolveRuc,
                icon: _isSubmitting
                    ? const SizedBox(
                        width: 18,
                        height: 18,
                        child: CircularProgressIndicator(
                          strokeWidth: 2,
                          color: Colors.white,
                        ),
                      )
                    : const Icon(Icons.search_rounded),
                label: Text(_isSubmitting ? 'Buscando...' : 'Buscar empresa'),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildCredentialsCard() {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Form(
          key: _formKey,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Row(
                children: [
                  IconButton(
                    onPressed: () => setState(() => _showRucStep = true),
                    icon: const Icon(Icons.arrow_back_rounded),
                    tooltip: 'Cambiar empresa',
                    visualDensity: VisualDensity.compact,
                    padding: EdgeInsets.zero,
                  ),
                  const SizedBox(width: 4),
                  Text(
                    'Iniciar sesion',
                    style: Theme.of(context).textTheme.titleLarge,
                  ),
                ],
              ),
              const SizedBox(height: 12),
              Container(
                padding:
                    const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
                decoration: BoxDecoration(
                  color: AppTokens.primary.withValues(alpha: 0.08),
                  borderRadius: BorderRadius.circular(8),
                ),
                child: Row(
                  children: [
                    Icon(
                      Icons.check_circle_rounded,
                      size: 20,
                      color: Colors.green.shade600,
                    ),
                    const SizedBox(width: 8),
                    Expanded(
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          if (_resolvedCompanyName != null &&
                              _resolvedCompanyName!.isNotEmpty)
                            Text(
                              _resolvedCompanyName!,
                              style: Theme.of(context)
                                  .textTheme
                                  .titleSmall
                                  ?.copyWith(
                                    fontWeight: FontWeight.w600,
                                  ),
                              maxLines: 1,
                              overflow: TextOverflow.ellipsis,
                            ),
                          Text(
                            'RUC: ${_rucController.text.trim()}',
                            style:
                                Theme.of(context).textTheme.bodySmall?.copyWith(
                                      color: AppTokens.secondary,
                                    ),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(height: 12),
              TextFormField(
                controller: _emailController,
                keyboardType: TextInputType.emailAddress,
                decoration: const InputDecoration(
                  labelText: 'Correo',
                  prefixIcon: Icon(Icons.alternate_email_rounded),
                ),
                validator: (value) {
                  if (value == null || value.trim().isEmpty) {
                    return 'Ingresa tu correo.';
                  }
                  return null;
                },
              ),
              const SizedBox(height: 14),
              TextFormField(
                key: const ValueKey('password_field'),
                controller: _passwordController,
                obscureText: _obscurePassword,
                decoration: InputDecoration(
                  labelText: 'Contrasena',
                  prefixIcon: const Icon(Icons.lock_rounded),
                  suffixIcon: IconButton(
                    onPressed: () =>
                        setState(() => _obscurePassword = !_obscurePassword),
                    icon: Icon(
                      _obscurePassword
                          ? Icons.visibility_off_rounded
                          : Icons.visibility_rounded,
                    ),
                  ),
                ),
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return 'Ingresa tu contrasena.';
                  }
                  return null;
                },
                onFieldSubmitted: (_) => _submit(),
              ),
              const SizedBox(height: 22),
              FilledButton.icon(
                onPressed: _isSubmitting ? null : _submit,
                icon: _isSubmitting
                    ? const SizedBox(
                        width: 18,
                        height: 18,
                        child: CircularProgressIndicator(
                          strokeWidth: 2,
                          color: Colors.white,
                        ),
                      )
                    : const Icon(Icons.arrow_forward_rounded),
                label: Text(_isSubmitting ? 'Conectando...' : 'Entrar'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _LoginHintRow extends StatelessWidget {
  const _LoginHintRow({
    required this.icon,
    required this.title,
    required this.subtitle,
  });

  final IconData icon;
  final String title;
  final String subtitle;

  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        CircleAvatar(
          backgroundColor: AppTokens.primary.withValues(alpha: 0.12),
          foregroundColor: AppTokens.primary,
          child: Icon(icon, size: 18),
        ),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(title, style: Theme.of(context).textTheme.titleSmall),
              const SizedBox(height: 4),
              Text(
                subtitle,
                style: Theme.of(context)
                    .textTheme
                    .bodyMedium
                    ?.copyWith(color: AppTokens.secondary),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _LoginBrandHeader extends StatelessWidget {
  const _LoginBrandHeader();

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Container(
          width: 108,
          height: 108,
          decoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(28),
            boxShadow: [
              BoxShadow(
                color: const Color(0xFF5F6CFB).withValues(alpha: 0.22),
                blurRadius: 32,
                offset: const Offset(0, 14),
              ),
            ],
          ),
          padding: const EdgeInsets.all(18),
          child: Image.asset(
            'assets/icon/app_icon.png',
            fit: BoxFit.contain,
          ),
        ),
        const SizedBox(height: 18),
        ShaderMask(
          shaderCallback: (rect) => const LinearGradient(
            colors: [Color(0xFF0D47A1), Color(0xFF009688)],
          ).createShader(rect),
          child: Text(
            'SysFarma',
            style: Theme.of(context).textTheme.displaySmall?.copyWith(
                  color: Colors.white,
                  fontWeight: FontWeight.w900,
                  letterSpacing: -0.5,
                ),
          ),
        ),
        const SizedBox(height: 6),
        Text(
          'Gestión comercial en la palma de tu mano',
          textAlign: TextAlign.center,
          style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                color: AppTokens.secondary,
                fontWeight: FontWeight.w500,
              ),
        ),
      ],
    );
  }
}