import 'package:sysfarma_mobile/src/app/widgets/app_panel.dart';
import 'package:sysfarma_mobile/src/app/widgets/empty_state_panel.dart';
import 'package:sysfarma_mobile/src/app/widgets/mini_trend_chart.dart';
import 'package:sysfarma_mobile/src/core/network/api_client.dart';
import 'package:sysfarma_mobile/src/core/network/mobile_api_response.dart';
import 'package:sysfarma_mobile/src/core/theme/app_tokens.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:share_plus/share_plus.dart';

enum _ReportPeriod { today, week, month }

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

  @override
  ConsumerState<GeneralReportScreen> createState() => _GeneralReportScreenState();
}

class _GeneralReportScreenState extends ConsumerState<GeneralReportScreen> {
  _ReportPeriod _period = _ReportPeriod.month;
  bool _isLoading = true;
  _ReportBundle? _bundle;
  DateTime? _lastUpdated;

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

  ({String period, String? dateStart, String? dateEnd}) _periodParams() {
    final now = DateTime.now();
    String fmt(DateTime d) =>
        '${d.year.toString().padLeft(4, '0')}-${d.month.toString().padLeft(2, '0')}-${d.day.toString().padLeft(2, '0')}';
    switch (_period) {
      case _ReportPeriod.today:
        return (period: 'date', dateStart: fmt(now), dateEnd: fmt(now));
      case _ReportPeriod.week:
        final start = now.subtract(const Duration(days: 6));
        return (period: 'date', dateStart: fmt(start), dateEnd: fmt(now));
      case _ReportPeriod.month:
        return (period: 'month', dateStart: null, dateEnd: null);
    }
  }

  Future<void> _refresh() async {
    if (mounted) setState(() => _isLoading = true);
    final api = ref.read(apiClientProvider);
    final params = _periodParams();
    try {
      final results = await Future.wait([
        api.salesReport(
            period: params.period,
            dateStart: params.dateStart,
            dateEnd: params.dateEnd),
        api.inventoryReport(),
        api.topProductsReport(
            period: params.period,
            dateStart: params.dateStart,
            dateEnd: params.dateEnd,
            limit: 10),
      ]);
      if (!mounted) return;
      setState(() {
        _bundle = _ReportBundle(
          sales: results[0],
          inventory: results[1],
          topProducts: results[2],
        );
        _lastUpdated = DateTime.now();
        _isLoading = false;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _bundle = _ReportBundle(
          sales: MobileApiResponse.failure(message: e.toString()),
          inventory: MobileApiResponse.failure(message: e.toString()),
          topProducts: MobileApiResponse.failure(message: e.toString()),
        );
        _isLoading = false;
      });
    }
  }

  void _changePeriod(_ReportPeriod period) {
    if (period == _period) return;
    setState(() => _period = period);
    _refresh();
  }

  Future<void> _shareSummary(_ReportBundle bundle) async {
    final salesData = bundle.sales.data ?? const <String, dynamic>{};
    final salesTotals =
        Map<String, dynamic>.from(salesData['totals'] as Map? ?? const {});
    final salesPeriod =
        Map<String, dynamic>.from(salesData['period'] as Map? ?? const {});
    final invData = bundle.inventory.data ?? const <String, dynamic>{};
    final invTotals =
        Map<String, dynamic>.from(invData['totals'] as Map? ?? const {});

    final lines = <String>[
      '📊 *Resumen ${_periodLabel()}*',
      '${salesPeriod['date_start'] ?? '-'} → ${salesPeriod['date_end'] ?? '-'}',
      '',
      '💰 Ventas: ${_fmtCurrency(salesTotals['total'])}',
      '🧾 Operaciones: ${salesTotals['operations_count'] ?? 0}',
      '🎯 Ticket promedio: ${_fmtCurrency(salesTotals['avg_ticket'])}',
      '',
      '📦 Inventario',
      '  Costo: ${_fmtCurrency(invTotals['stock_cost_value'])}',
      '  Venta: ${_fmtCurrency(invTotals['stock_sale_value'])}',
      '  Utilidad: ${_fmtCurrency(invTotals['potential_profit'])}',
    ];
    await Share.share(lines.join('\n'));
  }

  String _periodLabel() {
    switch (_period) {
      case _ReportPeriod.today:
        return 'de hoy';
      case _ReportPeriod.week:
        return 'de los últimos 7 días';
      case _ReportPeriod.month:
        return 'del mes';
    }
  }

  String _fmtCurrency(Object? value) {
    if (value == null) return 'S/ 0.00';
    final n = double.tryParse(value.toString()) ?? 0.0;
    final formatted = n.toStringAsFixed(2).replaceAllMapped(
          RegExp(r'(\d{1,3})(?=(\d{3})+(?!\d))'),
          (m) => '${m[1]},',
        );
    return 'S/ $formatted';
  }

  String _fmtTime(DateTime? dt) {
    if (dt == null) return '';
    final h = dt.hour.toString().padLeft(2, '0');
    final m = dt.minute.toString().padLeft(2, '0');
    return '$h:$m';
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: RefreshIndicator(
        onRefresh: _refresh,
        child: ListView(
          padding: AppTokens.pagePadding,
          children: [
            // Selector de periodo
            _PeriodSelector(
              active: _period,
              onChanged: _changePeriod,
            ),
            const SizedBox(height: 12),
            if (_isLoading) ...[
              const SizedBox(height: 24),
              const Center(child: CircularProgressIndicator()),
            ] else if (_bundle == null) ...[
              const SizedBox(height: 24),
              const Center(child: Text('Sin datos')),
            ] else
              ..._buildBody(_bundle!),
          ],
        ),
      ),
    );
  }

  List<Widget> _buildBody(_ReportBundle bundle) {
    final sales = bundle.sales;
    final inventory = bundle.inventory;
    final topProducts = bundle.topProducts;

    if (!sales.success || !inventory.success) {
      return [
        AppPanel(
          title: 'Reportes',
          subtitle: sales.message ??
              inventory.message ??
              'No se pudieron cargar los indicadores.',
          child: FilledButton.icon(
            onPressed: _refresh,
            icon: const Icon(Icons.refresh_rounded),
            label: const Text('Reintentar'),
          ),
        ),
      ];
    }

    final salesData = sales.data ?? const <String, dynamic>{};
    final salesTotals =
        Map<String, dynamic>.from(salesData['totals'] as Map? ?? const {});
    final salesGraph =
        Map<String, dynamic>.from(salesData['graph'] as Map? ?? const {});
    final comparison =
        Map<String, dynamic>.from(salesData['comparison'] as Map? ?? const {});
    final invData = inventory.data ?? const <String, dynamic>{};
    final invTotals =
        Map<String, dynamic>.from(invData['totals'] as Map? ?? const {});
    final topData = topProducts.data ?? const <String, dynamic>{};
    final topItems =
        List<Map<String, dynamic>>.from(topData['items'] as List? ?? const []);

    final operations = (salesTotals['operations_count'] ?? 0).toString();
    final avgTicket = salesTotals['avg_ticket'];
    final deltaPct = comparison['delta_pct'];
    final graphLabels =
        List<String>.from(salesGraph['labels'] as List? ?? const []);
    final graphSeries = _parseGraphSeries(salesGraph);

    return [
      // Hero compacto
      Container(
        padding: const EdgeInsets.all(20),
        decoration: BoxDecoration(
          gradient: const LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: [AppTokens.primary, AppTokens.primaryDark],
          ),
          borderRadius: BorderRadius.circular(AppTokens.radiusMedium),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(
                  child: Text(
                    'Ventas ${_periodLabel()}',
                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Colors.white.withValues(alpha: 0.85),
                        ),
                  ),
                ),
                if (_lastUpdated != null)
                  Text(
                    'Actualizado ${_fmtTime(_lastUpdated)}',
                    style: Theme.of(context).textTheme.labelSmall?.copyWith(
                          color: Colors.white.withValues(alpha: 0.75),
                        ),
                  ),
              ],
            ),
            const SizedBox(height: 4),
            Text(
              _fmtCurrency(salesTotals['total']),
              style: Theme.of(context).textTheme.displaySmall?.copyWith(
                    color: Colors.white,
                    fontWeight: FontWeight.w800,
                  ),
            ),
            const SizedBox(height: 6),
            Wrap(
              spacing: 8,
              runSpacing: 6,
              crossAxisAlignment: WrapCrossAlignment.center,
              children: [
                if (deltaPct != null)
                  _DeltaChip(deltaPct: (deltaPct as num).toDouble()),
                Text(
                  '$operations operación(es)',
                  style: Theme.of(context).textTheme.bodySmall?.copyWith(
                        color: Colors.white.withValues(alpha: 0.85),
                      ),
                ),
                if (avgTicket != null)
                  Text(
                    '· Ticket prom. ${_fmtCurrency(avgTicket)}',
                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: Colors.white.withValues(alpha: 0.85),
                        ),
                  ),
              ],
            ),
          ],
        ),
      ),
      const SizedBox(height: 14),

      // Tendencia
      if (graphLabels.isNotEmpty && graphSeries.isNotEmpty) ...[
        AppPanel(
          title: 'Tendencia',
          child: MiniTrendChart(
            labels: graphLabels.take(7).toList(),
            series: graphSeries
                .map((item) => MiniTrendSeries(
                      name: item.name,
                      values: item.values.take(7).toList(),
                      color: item.color,
                    ))
                .toList(),
          ),
        ),
        const SizedBox(height: 14),
      ],

      // Top productos vendidos
      AppPanel(
        title: 'Top productos vendidos',
        trailing: Text(
          '${topItems.length}',
          style: Theme.of(context).textTheme.titleMedium?.copyWith(
                color: AppTokens.primary,
                fontWeight: FontWeight.w700,
              ),
        ),
        child: topItems.isEmpty
            ? const EmptyStatePanel(
                icon: Icons.shopping_bag_outlined,
                title: 'Sin ventas',
                subtitle: 'No hay ventas en el período seleccionado.',
              )
            : Column(
                children: [
                  for (var i = 0; i < topItems.length; i++) ...[
                    _TopProductRow(
                      rank: i + 1,
                      item: topItems[i],
                      formatter: _fmtCurrency,
                    ),
                    if (i < topItems.length - 1) const Divider(height: 16),
                  ],
                ],
              ),
      ),
      const SizedBox(height: 14),

      // Inventario consolidado
      AppPanel(
        title: 'Inventario',
        child: Column(
          children: [
            _ReportLine(
                label: 'Stock total',
                value: '${invTotals['stock'] ?? 0} uds'),
            const Divider(height: 22),
            _ReportLine(
                label: 'Costo',
                value: _fmtCurrency(invTotals['stock_cost_value'])),
            const Divider(height: 22),
            _ReportLine(
                label: 'Valor de venta',
                value: _fmtCurrency(invTotals['stock_sale_value'])),
            const Divider(height: 22),
            _ReportLine(
                label: 'Utilidad potencial',
                value: _fmtCurrency(invTotals['potential_profit'])),
          ],
        ),
      ),
      const SizedBox(height: 14),

      // Compartir
      SizedBox(
        width: double.infinity,
        child: FilledButton.icon(
          onPressed: () => _shareSummary(bundle),
          icon: const Icon(Icons.share_rounded),
          label: const Text('Compartir resumen'),
          style: FilledButton.styleFrom(backgroundColor: AppTokens.cta),
        ),
      ),
      const SizedBox(height: 24),
    ];
  }

  List<_ChartSeries> _parseGraphSeries(Map<String, dynamic> graph) {
    final datasets =
        List<Map<String, dynamic>>.from(graph['datasets'] as List? ?? const []);
    return datasets.map((dataset) {
      return _ChartSeries(
        name: dataset['name']?.toString() ??
            dataset['label']?.toString() ??
            'Serie',
        values: List<double>.from(
          (dataset['data'] as List? ?? const [])
              .map((value) => double.tryParse('$value') ?? 0),
        ),
        color: _parseColor(dataset['color']?.toString()) ?? AppTokens.primary,
      );
    }).toList();
  }

  Color? _parseColor(String? raw) {
    if (raw == null || raw.isEmpty) return null;
    final normalized =
        raw.replaceAll('#', '').replaceAll('rgb(', '').replaceAll(')', '');
    if (normalized.contains(',')) {
      final parts = normalized
          .split(',')
          .map((item) => int.tryParse(item.trim()) ?? 0)
          .toList();
      if (parts.length == 3) {
        return Color.fromRGBO(parts[0], parts[1], parts[2], 1);
      }
    }
    if (normalized.length == 6) {
      return Color(int.parse('FF$normalized', radix: 16));
    }
    return null;
  }
}

class _PeriodSelector extends StatelessWidget {
  const _PeriodSelector({required this.active, required this.onChanged});

  final _ReportPeriod active;
  final ValueChanged<_ReportPeriod> onChanged;

  @override
  Widget build(BuildContext context) {
    Widget pill(_ReportPeriod p, String label) {
      final selected = p == active;
      return Expanded(
        child: Material(
          color: Colors.transparent,
          child: InkWell(
            borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
            onTap: () => onChanged(p),
            child: Container(
              padding: const EdgeInsets.symmetric(vertical: 12),
              decoration: BoxDecoration(
                color: selected
                    ? AppTokens.primary.withValues(alpha: 0.10)
                    : Colors.transparent,
                borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
              ),
              child: Center(
                child: Text(
                  label,
                  style: Theme.of(context).textTheme.labelLarge?.copyWith(
                        color: selected
                            ? AppTokens.primary
                            : AppTokens.secondary,
                        fontWeight:
                            selected ? FontWeight.w700 : FontWeight.w500,
                      ),
                ),
              ),
            ),
          ),
        ),
      );
    }

    return Container(
      decoration: BoxDecoration(
        color: AppTokens.surface,
        borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
        border: Border.all(color: AppTokens.border),
      ),
      child: Row(
        children: [
          pill(_ReportPeriod.today, 'Hoy'),
          pill(_ReportPeriod.week, '7 días'),
          pill(_ReportPeriod.month, 'Mes'),
        ],
      ),
    );
  }
}

class _DeltaChip extends StatelessWidget {
  const _DeltaChip({required this.deltaPct});
  final double deltaPct;

  @override
  Widget build(BuildContext context) {
    final positive = deltaPct >= 0;
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.20),
        borderRadius: BorderRadius.circular(999),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(
            positive ? Icons.trending_up_rounded : Icons.trending_down_rounded,
            size: 14,
            color: Colors.white,
          ),
          const SizedBox(width: 4),
          Text(
            '${positive ? '+' : ''}${deltaPct.toStringAsFixed(1)}%',
            style: const TextStyle(
              color: Colors.white,
              fontSize: 12,
              fontWeight: FontWeight.w700,
            ),
          ),
        ],
      ),
    );
  }
}

class _ReportLine extends StatelessWidget {
  const _ReportLine({required this.label, required this.value});

  final String label;
  final String value;

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Expanded(
          child: Text(
            label,
            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: AppTokens.secondary,
                ),
          ),
        ),
        Text(
          value,
          style: Theme.of(context).textTheme.titleSmall?.copyWith(
                fontWeight: FontWeight.w700,
              ),
        ),
      ],
    );
  }
}

class _TopProductRow extends StatelessWidget {
  const _TopProductRow({
    required this.rank,
    required this.item,
    required this.formatter,
  });

  final int rank;
  final Map<String, dynamic> item;
  final String Function(Object?) formatter;

  @override
  Widget build(BuildContext context) {
    final qty = item['quantity']?.toString() ?? '0';
    final desc = item['description']?.toString() ?? '-';
    final total = item['total'];
    return Row(
      children: [
        SizedBox(
          width: 22,
          child: Text(
            '$rank.',
            style: Theme.of(context).textTheme.titleSmall?.copyWith(
                  color: AppTokens.secondary,
                  fontWeight: FontWeight.w700,
                ),
          ),
        ),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                desc,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: Theme.of(context).textTheme.titleSmall,
              ),
              const SizedBox(height: 2),
              Text(
                '$qty u',
                style: Theme.of(context).textTheme.labelSmall?.copyWith(
                      color: AppTokens.secondary,
                    ),
              ),
            ],
          ),
        ),
        Text(
          formatter(total),
          style: Theme.of(context).textTheme.titleSmall?.copyWith(
                color: AppTokens.primary,
                fontWeight: FontWeight.w700,
              ),
        ),
      ],
    );
  }
}

class _ReportBundle {
  const _ReportBundle({
    required this.sales,
    required this.inventory,
    required this.topProducts,
  });

  final MobileApiResponse<Map<String, dynamic>> sales;
  final MobileApiResponse<Map<String, dynamic>> inventory;
  final MobileApiResponse<Map<String, dynamic>> topProducts;
}

class _ChartSeries {
  const _ChartSeries({
    required this.name,
    required this.values,
    required this.color,
  });

  final String name;
  final List<double> values;
  final Color color;
}