import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:intl/intl.dart';
import 'package:fl_chart/fl_chart.dart';
import '../providers/factura_provider.dart';
import '../providers/configuracion_provider.dart';

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

  @override
  State<EstadisticasScreen> createState() => _EstadisticasScreenState();
}

class _EstadisticasScreenState extends State<EstadisticasScreen> {
  late int _year;

  @override
  void initState() {
    super.initState();
    _year = DateTime.now().year;
  }

  @override
  Widget build(BuildContext context) {
    final facturaProv = context.watch<FacturaProvider>();
    final configProv = context.watch<ConfiguracionProvider>();
    final moneda = configProv.config?.moneda ?? 'USD';
    final symbol = moneda == 'USD' ? '\$' : moneda == 'EUR' ? '€' : moneda == 'MXN' ? 'MX\$' : '\$';

    return Scaffold(
      appBar: AppBar(title: const Text('Estadísticas')),
      body: FutureBuilder(
        future: Future.wait([
          facturaProv.gastoMensual(_year),
          facturaProv.gastosPorServicio(_year, DateTime.now().month),
          facturaProv.totalGastadoMes(_year, DateTime.now().month),
        ]),
        builder: (context, AsyncSnapshot<List<dynamic>> snapshot) {
          if (!snapshot.hasData) return const Center(child: CircularProgressIndicator());

          final gastoMensual = snapshot.data![0] as List<Map<String, dynamic>>;
          final gastoPorServicio = snapshot.data![1] as Map<String, double>;
          final totalMes = snapshot.data![2] as double;

          return ListView(
            padding: const EdgeInsets.all(16),
            children: [
              Text('Resumen $_year', style: Theme.of(context).textTheme.titleLarge),
              const SizedBox(height: 8),
              Card(
                child: Padding(
                  padding: const EdgeInsets.all(16),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text('Gasto mensual actual', style: Theme.of(context).textTheme.titleSmall),
                      Text('$symbol${NumberFormat('#,##0.00').format(totalMes)}',
                          style: Theme.of(context).textTheme.headlineMedium),
                    ],
                  ),
                ),
              ),
              const SizedBox(height: 20),
              Text('Gasto mensual ($_year)', style: Theme.of(context).textTheme.titleMedium),
              const SizedBox(height: 8),
              SizedBox(
                height: 200,
                child: BarChart(
                  BarChartData(
                    alignment: BarChartAlignment.spaceAround,
                    maxY: (gastoMensual.isEmpty ? 1000 : gastoMensual.map((e) => (e['total'] as num).toDouble()).reduce((a, b) => a > b ? a : b)) * 1.2,
                    barGroups: List.generate(12, (i) {
                      final mes = (i + 1).toString().padLeft(2, '0');
                      final data = gastoMensual.where((e) => e['mes'] == mes).firstOrNull;
                      return BarChartGroupData(
                        x: i,
                        barRods: [
                          BarChartRodData(
                            toY: data != null ? (data['total'] as num).toDouble() : 0,
                            color: Theme.of(context).colorScheme.primary,
                            width: 16,
                            borderRadius: const BorderRadius.vertical(top: Radius.circular(4)),
                          ),
                        ],
                      );
                    }),
                    titlesData: FlTitlesData(
                      leftTitles: AxisTitles(sideTitles: SideTitles(showTitles: true, reservedSize: 40, getTitlesWidget: (v, _) => Text('$symbol${v.toInt()}', style: const TextStyle(fontSize: 10)))),
                      bottomTitles: AxisTitles(sideTitles: SideTitles(showTitles: true, getTitlesWidget: (v, _) {
                        const meses = ['E', 'F', 'M', 'A', 'M', 'J', 'J', 'A', 'S', 'O', 'N', 'D'];
                        return Text(meses[v.toInt()], style: const TextStyle(fontSize: 10));
                      })),
                      rightTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
                      topTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
                    ),
                    gridData: FlGridData(show: true, drawVerticalLine: false, horizontalInterval: (gastoMensual.isEmpty ? 1000 : gastoMensual.map((e) => (e['total'] as num).toDouble()).reduce((a, b) => a > b ? a : b)) / 4),
                    borderData: FlBorderData(show: false),
                  ),
                ),
              ),
              const SizedBox(height: 20),
              Text('Distribución por servicio', style: Theme.of(context).textTheme.titleMedium),
              const SizedBox(height: 8),
              if (gastoPorServicio.isEmpty)
                Card(child: Padding(padding: const EdgeInsets.all(16), child: Text('Sin datos este mes')))
              else
                Card(
                  child: Padding(
                    padding: const EdgeInsets.all(16),
                    child: Column(
                      children: gastoPorServicio.entries.map((e) {
                        final total = gastoPorServicio.values.fold(0.0, (a, b) => a + b);
                        final pct = total > 0 ? e.value / total * 100 : 0.0;
                        return Padding(
                          padding: const EdgeInsets.only(bottom: 8),
                          child: Row(
                            children: [
                              SizedBox(width: 100, child: Text(e.key, style: const TextStyle(fontSize: 13))),
                              Expanded(
                                child: ClipRRect(
                                  borderRadius: BorderRadius.circular(4),
                                  child: LinearProgressIndicator(
                                    value: pct / 100,
                                    backgroundColor: Colors.grey[200],
                                    minHeight: 12,
                                  ),
                                ),
                              ),
                              const SizedBox(width: 8),
                              SizedBox(width: 70, child: Text('$symbol${NumberFormat('#,##0.00').format(e.value)}', style: const TextStyle(fontSize: 12), textAlign: TextAlign.right)),
                            ],
                          ),
                        );
                      }).toList(),
                    ),
                  ),
                ),
            ],
          );
        },
      ),
    );
  }
}