import 'package:flutter/material.dart';
import '../../core/theme/app_theme.dart';
import '../../core/widgets/app_widgets.dart';

// ── Modelos locales ───────────────────────────────────────────────────────────
enum TruckStatus { disponible, enRuta, mantenimiento, detenido }

extension TruckStatusX on TruckStatus {
  String get label => switch (this) {
        TruckStatus.disponible => 'Disponible',
        TruckStatus.enRuta => 'En ruta',
        TruckStatus.mantenimiento => 'Mantenimiento',
        TruckStatus.detenido => 'Detenido',
      };

  AppStatusBadge get badge => switch (this) {
        TruckStatus.disponible => AppStatusBadge.green(label),
        TruckStatus.enRuta => AppStatusBadge.amber(label),
        TruckStatus.mantenimiento => AppStatusBadge.gray(label),
        TruckStatus.detenido => AppStatusBadge.gray(label),
      };
}

class _AdminUser {
  final String id, nombre, apellido, email, telefono;
  const _AdminUser({
    required this.id,
    required this.nombre,
    required this.apellido,
    required this.email,
    required this.telefono,
  });
  String get nombreCompleto => '$nombre $apellido';
  String get iniciales =>
      '${nombre.isNotEmpty ? nombre[0] : ''}${apellido.isNotEmpty ? apellido[0] : ''}'
          .toUpperCase();
  _AdminUser copyWith({String? nombre, String? apellido, String? email, String? telefono}) =>
      _AdminUser(id: id, nombre: nombre ?? this.nombre, apellido: apellido ?? this.apellido, email: email ?? this.email, telefono: telefono ?? this.telefono);
}

class _AdminRoute {
  final String id, nombre, zona;
  final bool activa;
  const _AdminRoute({required this.id, required this.nombre, required this.zona, this.activa = true});
  _AdminRoute copyWith({String? nombre, String? zona, bool? activa}) =>
      _AdminRoute(id: id, nombre: nombre ?? this.nombre, zona: zona ?? this.zona, activa: activa ?? this.activa);
}

class _AdminTruck {
  final String id, placas, modelo, conductor, rutaId;
  final TruckStatus status;
  const _AdminTruck({
    required this.id, required this.placas, required this.modelo,
    required this.conductor, required this.status, required this.rutaId,
  });
  _AdminTruck copyWith({String? placas, String? modelo, String? conductor, TruckStatus? status, String? rutaId}) =>
      _AdminTruck(id: id, placas: placas ?? this.placas, modelo: modelo ?? this.modelo, conductor: conductor ?? this.conductor, status: status ?? this.status, rutaId: rutaId ?? this.rutaId);
}

// ── Pantalla ──────────────────────────────────────────────────────────────────
class AdminScreen extends StatefulWidget {
  const AdminScreen({super.key});

  @override
  State<AdminScreen> createState() => _AdminScreenState();
}

class _AdminScreenState extends State<AdminScreen>
    with SingleTickerProviderStateMixin {
  late final TabController _tabController;
  int _activeTab = 0;

  final List<_AdminUser> _usuarios = [
    const _AdminUser(id: 'u-01', nombre: 'Laura', apellido: 'Gómez', email: 'laura@recolecta.com', telefono: '+52 461 987 1234'),
    const _AdminUser(id: 'u-02', nombre: 'Miguel', apellido: 'Sánchez', email: 'miguel@recolecta.com', telefono: '+52 461 123 7890'),
  ];

  final List<_AdminRoute> _rutas = [
    const _AdminRoute(id: 'RUTA-01', nombre: 'Ruta Norte', zona: 'Zona Norte'),
    const _AdminRoute(id: 'RUTA-02', nombre: 'Ruta Sur', zona: 'Zona Sur', activa: false),
  ];

  final List<_AdminTruck> _camiones = [
    const _AdminTruck(id: 't-01', placas: 'GTO-101', modelo: 'Volvo FH', conductor: 'Javier Pérez', status: TruckStatus.enRuta, rutaId: 'RUTA-01'),
    const _AdminTruck(id: 't-02', placas: 'GTO-103', modelo: 'Mercedes 1830', conductor: 'Ana Díaz', status: TruckStatus.disponible, rutaId: 'RUTA-02'),
  ];

  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 3, vsync: this)
      ..addListener(() {
        if (!_tabController.indexIsChanging) {
          setState(() => _activeTab = _tabController.index);
        }
      });
  }

  @override
  void dispose() {
    _tabController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: AppTheme.background,
      appBar: AppBar(
        title: const Text('Panel de administración'),
        bottom: TabBar(
          controller: _tabController,
          indicatorColor: Colors.white,
          labelColor: Colors.white,
          unselectedLabelColor: Colors.white70,
          tabs: const [
            Tab(text: 'Usuarios'),
            Tab(text: 'Rutas'),
            Tab(text: 'Camiones'),
          ],
        ),
      ),
      body: TabBarView(
        controller: _tabController,
        children: [
          _buildUsersTab(),
          _buildRoutesTab(),
          _buildTrucksTab(),
        ],
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () {
          if (_activeTab == 0) _showUserForm();
          else if (_activeTab == 1) _showRouteForm();
          else _showTruckForm();
        },
        backgroundColor: AppTheme.primary,
        label: Text(_activeTab == 0 ? 'Nuevo usuario' : _activeTab == 1 ? 'Nueva ruta' : 'Nuevo camión'),
        icon: const Icon(Icons.add),
      ),
    );
  }

  // ── Tab usuarios ────────────────────────────────────────────────────────────
  Widget _buildUsersTab() {
    if (_usuarios.isEmpty) return _emptyState('No hay usuarios registrados.');
    return ListView.separated(
      padding: const EdgeInsets.all(16),
      itemCount: _usuarios.length,
      separatorBuilder: (_, i) => const SizedBox(height: 12),
      itemBuilder: (context, i) {
        final u = _usuarios[i];
        return AppCard(
          child: Row(
            children: [
              CircleAvatar(
                backgroundColor: AppTheme.primaryLight,
                foregroundColor: AppTheme.primary,
                child: Text(u.iniciales),
              ),
              const SizedBox(width: 14),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(u.nombreCompleto, style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
                    const SizedBox(height: 4),
                    Text(u.email, style: const TextStyle(fontSize: 13, color: AppTheme.textSecondary)),
                    Text(u.telefono, style: const TextStyle(fontSize: 13)),
                  ],
                ),
              ),
              IconButton(icon: const Icon(Icons.edit_outlined, color: AppTheme.primary), onPressed: () => _showUserForm(user: u)),
              IconButton(icon: const Icon(Icons.delete_outline, color: AppTheme.danger), onPressed: () => _confirmDelete('usuario', () => setState(() => _usuarios.removeWhere((x) => x.id == u.id)))),
            ],
          ),
        );
      },
    );
  }

  // ── Tab rutas ───────────────────────────────────────────────────────────────
  Widget _buildRoutesTab() {
    if (_rutas.isEmpty) return _emptyState('No hay rutas registradas.');
    return ListView.separated(
      padding: const EdgeInsets.all(16),
      itemCount: _rutas.length,
      separatorBuilder: (_, i) => const SizedBox(height: 12),
      itemBuilder: (context, i) {
        final r = _rutas[i];
        return AppCard(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Expanded(child: Text(r.nombre, style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600))),
                  r.activa ? AppStatusBadge.green('Activa') : AppStatusBadge.gray('Inactiva'),
                ],
              ),
              const SizedBox(height: 6),
              Text(r.zona, style: const TextStyle(fontSize: 13, color: AppTheme.textSecondary)),
              const SizedBox(height: 12),
              Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  TextButton.icon(onPressed: () => _showRouteForm(route: r), icon: const Icon(Icons.edit_outlined, size: 18), label: const Text('Editar')),
                  const SizedBox(width: 8),
                  TextButton.icon(
                    onPressed: () => _confirmDelete('ruta', () => setState(() => _rutas.removeWhere((x) => x.id == r.id))),
                    icon: const Icon(Icons.delete_outline, size: 18),
                    label: const Text('Eliminar'),
                    style: TextButton.styleFrom(foregroundColor: AppTheme.danger),
                  ),
                ],
              ),
            ],
          ),
        );
      },
    );
  }

  // ── Tab camiones ────────────────────────────────────────────────────────────
  Widget _buildTrucksTab() {
    if (_camiones.isEmpty) return _emptyState('No hay camiones registrados.');
    return ListView.separated(
      padding: const EdgeInsets.all(16),
      itemCount: _camiones.length,
      separatorBuilder: (_, i) => const SizedBox(height: 12),
      itemBuilder: (context, i) {
        final t = _camiones[i];
        final ruta = _rutas.firstWhere((r) => r.id == t.rutaId, orElse: () => const _AdminRoute(id: '', nombre: 'Sin ruta', zona: ''));
        return AppCard(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Expanded(child: Text(t.placas, style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600))),
                  t.status.badge,
                ],
              ),
              const SizedBox(height: 6),
              Text('${t.modelo} · ${t.conductor}', style: const TextStyle(fontSize: 13)),
              Text('Ruta: ${ruta.nombre}', style: const TextStyle(fontSize: 13, color: AppTheme.textSecondary)),
              const SizedBox(height: 12),
              Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  TextButton.icon(onPressed: () => _showTruckForm(truck: t), icon: const Icon(Icons.edit_outlined, size: 18), label: const Text('Editar')),
                  const SizedBox(width: 8),
                  TextButton.icon(
                    onPressed: () => _confirmDelete('camión', () => setState(() => _camiones.removeWhere((x) => x.id == t.id))),
                    icon: const Icon(Icons.delete_outline, size: 18),
                    label: const Text('Eliminar'),
                    style: TextButton.styleFrom(foregroundColor: AppTheme.danger),
                  ),
                ],
              ),
            ],
          ),
        );
      },
    );
  }

  Widget _emptyState(String msg) => Center(child: Padding(padding: const EdgeInsets.all(24), child: Text(msg, textAlign: TextAlign.center, style: const TextStyle(fontSize: 15, color: AppTheme.textSecondary))));

  // ── Confirmación de borrado ─────────────────────────────────────────────────
  void _confirmDelete(String tipo, VoidCallback onConfirm) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: AppTheme.surface,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(AppTheme.radiusLg)),
        title: Text('Eliminar $tipo'),
        content: Text('¿Deseas eliminar este $tipo?'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx), style: TextButton.styleFrom(foregroundColor: AppTheme.textSecondary), child: const Text('Cancelar')),
          TextButton(
            onPressed: () { onConfirm(); Navigator.pop(ctx); },
            style: TextButton.styleFrom(foregroundColor: AppTheme.danger),
            child: const Text('Eliminar'),
          ),
        ],
      ),
    );
  }

  // ── Formulario usuario ──────────────────────────────────────────────────────
  void _showUserForm({_AdminUser? user}) {
    final nombreCtrl = TextEditingController(text: user?.nombre);
    final apellidoCtrl = TextEditingController(text: user?.apellido);
    final emailCtrl = TextEditingController(text: user?.email);
    final telefonoCtrl = TextEditingController(text: user?.telefono);
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: AppTheme.surface,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(AppTheme.radiusLg)),
        title: Text(user == null ? 'Nuevo usuario' : 'Editar usuario'),
        content: SingleChildScrollView(
          child: Column(mainAxisSize: MainAxisSize.min, children: [
            TextField(controller: nombreCtrl, decoration: const InputDecoration(labelText: 'Nombre')),
            TextField(controller: apellidoCtrl, decoration: const InputDecoration(labelText: 'Apellido')),
            TextField(controller: emailCtrl, decoration: const InputDecoration(labelText: 'Correo'), keyboardType: TextInputType.emailAddress),
            TextField(controller: telefonoCtrl, decoration: const InputDecoration(labelText: 'Teléfono'), keyboardType: TextInputType.phone),
          ]),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx), style: TextButton.styleFrom(foregroundColor: AppTheme.textSecondary), child: const Text('Cancelar')),
          TextButton(
            onPressed: () {
              final nuevo = _AdminUser(id: user?.id ?? 'u-${DateTime.now().millisecondsSinceEpoch}', nombre: nombreCtrl.text.trim(), apellido: apellidoCtrl.text.trim(), email: emailCtrl.text.trim(), telefono: telefonoCtrl.text.trim());
              setState(() {
                if (user == null) { _usuarios.add(nuevo); }
                else { final idx = _usuarios.indexWhere((x) => x.id == user.id); if (idx >= 0) _usuarios[idx] = nuevo; }
              });
              Navigator.pop(ctx);
            },
            child: Text(user == null ? 'Crear' : 'Guardar'),
          ),
        ],
      ),
    );
  }

  // ── Formulario ruta ─────────────────────────────────────────────────────────
  void _showRouteForm({_AdminRoute? route}) {
    final nombreCtrl = TextEditingController(text: route?.nombre);
    final zonaCtrl = TextEditingController(text: route?.zona);
    bool activa = route?.activa ?? true;
    showDialog(
      context: context,
      builder: (ctx) => StatefulBuilder(
        builder: (ctx, setInner) => AlertDialog(
          backgroundColor: AppTheme.surface,
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(AppTheme.radiusLg)),
          title: Text(route == null ? 'Nueva ruta' : 'Editar ruta'),
          content: Column(mainAxisSize: MainAxisSize.min, children: [
            TextField(controller: nombreCtrl, decoration: const InputDecoration(labelText: 'Nombre de ruta')),
            TextField(controller: zonaCtrl, decoration: const InputDecoration(labelText: 'Zona')),
            Row(children: [
              const Expanded(child: Text('Ruta activa')),
              Switch.adaptive(value: activa, onChanged: (v) => setInner(() => activa = v)),
            ]),
          ]),
          actions: [
            TextButton(onPressed: () => Navigator.pop(ctx), style: TextButton.styleFrom(foregroundColor: AppTheme.textSecondary), child: const Text('Cancelar')),
            TextButton(
              onPressed: () {
                final nueva = _AdminRoute(id: route?.id ?? 'r-${DateTime.now().millisecondsSinceEpoch}', nombre: nombreCtrl.text.trim(), zona: zonaCtrl.text.trim(), activa: activa);
                setState(() {
                  if (route == null) { _rutas.add(nueva); }
                  else { final idx = _rutas.indexWhere((x) => x.id == route.id); if (idx >= 0) _rutas[idx] = nueva; }
                });
                Navigator.pop(ctx);
              },
              child: Text(route == null ? 'Crear' : 'Guardar'),
            ),
          ],
        ),
      ),
    );
  }

  // ── Formulario camión ───────────────────────────────────────────────────────
  void _showTruckForm({_AdminTruck? truck}) {
    final placasCtrl = TextEditingController(text: truck?.placas);
    final modeloCtrl = TextEditingController(text: truck?.modelo);
    final conductorCtrl = TextEditingController(text: truck?.conductor);
    TruckStatus status = truck?.status ?? TruckStatus.disponible;
    String selectedRuta = truck?.rutaId ?? (_rutas.isNotEmpty ? _rutas.first.id : '');
    showDialog(
      context: context,
      builder: (ctx) => StatefulBuilder(
        builder: (ctx, setInner) => AlertDialog(
          backgroundColor: AppTheme.surface,
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(AppTheme.radiusLg)),
          title: Text(truck == null ? 'Nuevo camión' : 'Editar camión'),
          content: SingleChildScrollView(
            child: Column(mainAxisSize: MainAxisSize.min, children: [
              TextField(controller: placasCtrl, decoration: const InputDecoration(labelText: 'Placas')),
              TextField(controller: modeloCtrl, decoration: const InputDecoration(labelText: 'Modelo')),
              TextField(controller: conductorCtrl, decoration: const InputDecoration(labelText: 'Conductor')),
              const SizedBox(height: 12),
              DropdownButtonFormField<String>(
                value: selectedRuta.isEmpty ? null : selectedRuta,
                decoration: const InputDecoration(labelText: 'Ruta'),
                items: _rutas.map((r) => DropdownMenuItem(value: r.id, child: Text(r.nombre))).toList(),
                onChanged: (v) { if (v != null) setInner(() => selectedRuta = v); },
              ),
              const SizedBox(height: 12),
              DropdownButtonFormField<TruckStatus>(
                value: status,
                decoration: const InputDecoration(labelText: 'Estatus'),
                items: TruckStatus.values.map((s) => DropdownMenuItem(value: s, child: Text(s.label))).toList(),
                onChanged: (v) { if (v != null) setInner(() => status = v); },
              ),
            ]),
          ),
          actions: [
            TextButton(onPressed: () => Navigator.pop(ctx), style: TextButton.styleFrom(foregroundColor: AppTheme.textSecondary), child: const Text('Cancelar')),
            TextButton(
              onPressed: () {
                final nuevo = _AdminTruck(id: truck?.id ?? 't-${DateTime.now().millisecondsSinceEpoch}', placas: placasCtrl.text.trim(), modelo: modeloCtrl.text.trim(), conductor: conductorCtrl.text.trim(), status: status, rutaId: selectedRuta);
                setState(() {
                  if (truck == null) { _camiones.add(nuevo); }
                  else { final idx = _camiones.indexWhere((x) => x.id == truck.id); if (idx >= 0) _camiones[idx] = nuevo; }
                });
                Navigator.pop(ctx);
              },
              child: Text(truck == null ? 'Crear' : 'Guardar'),
            ),
          ],
        ),
      ),
    );
  }
}