import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:intl/intl.dart';
import '../models/factura.dart';
import '../providers/factura_provider.dart';
import '../providers/servicio_provider.dart';

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

  @override
  State<CrearFacturaScreen> createState() => _CrearFacturaScreenState();
}

class _CrearFacturaScreenState extends State<CrearFacturaScreen> {
  final _formKey = GlobalKey<FormState>();
  late TextEditingController _montoCtrl;
  late TextEditingController _notaCtrl;
  int? _servicioId;
  DateTime _fechaEmision = DateTime.now();
  DateTime _fechaVencimiento = DateTime.now().add(const Duration(days: 30));
  String _estado = 'Pendiente';

  @override
  void initState() {
    super.initState();
    _montoCtrl = TextEditingController();
    _notaCtrl = TextEditingController();
    context.read<ServicioProvider>().cargarServicios();
  }

  @override
  void dispose() {
    _montoCtrl.dispose();
    _notaCtrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final servicioProv = context.watch<ServicioProvider>();
    final facturaProv = context.read<FacturaProvider>();

    return Scaffold(
      appBar: AppBar(title: const Text('Nueva factura')),
      body: Form(
        key: _formKey,
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            DropdownButtonFormField<int>(
              value: _servicioId,
              decoration: const InputDecoration(labelText: 'Servicio', border: OutlineInputBorder()),
              items: servicioProv.servicios.map((s) => DropdownMenuItem(value: s.id, child: Text(s.nombre))).toList(),
              onChanged: (v) => setState(() => _servicioId = v),
              validator: (v) => v == null ? 'Selecciona un servicio' : null,
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _montoCtrl,
              decoration: const InputDecoration(labelText: 'Monto', border: OutlineInputBorder(), prefixText: '\$ '),
              keyboardType: TextInputType.numberWithOptions(decimal: true),
              validator: (v) {
                if (v == null || v.isEmpty) return 'Ingresa el monto';
                if (double.tryParse(v) == null) return 'Monto inválido';
                return null;
              },
            ),
            const SizedBox(height: 16),
            ListTile(
              title: const Text('Fecha de emisión'),
              subtitle: Text(DateFormat('yyyy-MM-dd').format(_fechaEmision)),
              trailing: const Icon(Icons.calendar_today),
              onTap: () async {
                final date = await showDatePicker(context: context, firstDate: DateTime(2020), lastDate: DateTime(2035), initialDate: _fechaEmision);
                if (date != null) setState(() => _fechaEmision = date);
              },
            ),
            ListTile(
              title: const Text('Fecha de vencimiento'),
              subtitle: Text(DateFormat('yyyy-MM-dd').format(_fechaVencimiento)),
              trailing: const Icon(Icons.calendar_today),
              onTap: () async {
                final date = await showDatePicker(context: context, firstDate: DateTime(2020), lastDate: DateTime(2035), initialDate: _fechaVencimiento);
                if (date != null) setState(() => _fechaVencimiento = date);
              },
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _notaCtrl,
              decoration: const InputDecoration(labelText: 'Nota (opcional)', border: OutlineInputBorder()),
              maxLines: 2,
            ),
            const SizedBox(height: 16),
            SegmentedButton<String>(
              segments: const [
                ButtonSegment(value: 'Pendiente', label: Text('Pendiente')),
                ButtonSegment(value: 'Pagada', label: Text('Pagada')),
              ],
              selected: {_estado},
              onSelectionChanged: (v) => setState(() => _estado = v.first),
            ),
            const SizedBox(height: 32),
            FilledButton(
              onPressed: () async {
                if (!_formKey.currentState!.validate()) return;
                final factura = Factura(
                  servicioId: _servicioId!,
                  monto: double.parse(_montoCtrl.text),
                  fechaEmision: DateFormat('yyyy-MM-dd').format(_fechaEmision),
                  fechaVencimiento: DateFormat('yyyy-MM-dd').format(_fechaVencimiento),
                  estado: _estado,
                  nota: _notaCtrl.text.isEmpty ? null : _notaCtrl.text,
                  fechaPago: _estado == 'Pagada' ? DateFormat('yyyy-MM-dd').format(DateTime.now()) : null,
                );
                await facturaProv.agregarFactura(factura);
                if (context.mounted) Navigator.pop(context);
              },
              child: const Text('Guardar factura'),
            ),
          ],
        ),
      ),
    );
  }
}