import 'package:decimal/decimal.dart';
import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../core/utils/ru_date.dart';
import '../../core/widgets/async_value_view.dart';
import '../../core/widgets/empty_state.dart';
import '../../core/widgets/money_text.dart';
import '../../core/widgets/section_card.dart';
import 'data/income_api.dart';
import 'labels.dart';
import 'providers.dart';

/// История: what was actually paid, by month and kind. Facts only — no basis column here,
/// because every row is `paid` by construction.
class IncomeHistoryTab extends ConsumerWidget {
  const IncomeHistoryTab({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final history = ref.watch(incomeHistoryProvider);

    return RefreshIndicator(
      onRefresh: () async => ref.invalidate(incomeHistoryProvider),
      child: AsyncValueView(
        value: history,
        onRetry: () => ref.invalidate(incomeHistoryProvider),
        data: (data) {
          if (data.rows.isEmpty) {
            return ListView(
              padding: const EdgeInsets.all(16),
              children: const [
                _PeriodChips(),
                SizedBox(height: 48),
                EmptyState(
                  icon: Icons.history,
                  message: 'Выплат за период не было.',
                ),
              ],
            );
          }
          final months = _byMonth(data.rows);
          return ListView(
            padding: const EdgeInsets.all(16),
            children: [
              const _PeriodChips(),
              const SizedBox(height: 12),
              Wrap(
                spacing: 12,
                runSpacing: 12,
                children: [
                  StatTile(
                    label: 'Получено',
                    value: MoneyText(data.totalRub, currency: 'RUB'),
                    note: 'за выбранный период, до налога',
                  ),
                  StatTile(
                    label: 'Удержано налога',
                    value: MoneyText(data.taxWithheldRub, currency: 'RUB'),
                    note: 'по данным брокера',
                  ),
                  StatTile(
                    label: 'Месяцев с выплатами',
                    value: Text('${months.length}'),
                    note: 'строк в таблице: ${data.rows.length}',
                  ),
                ],
              ),
              const SizedBox(height: 16),
              SectionCard(
                title: 'Выплаты по месяцам',
                child: SizedBox(
                  height: 220,
                  child: SingleChildScrollView(
                    scrollDirection: Axis.horizontal,
                    reverse: true,
                    child: SizedBox(
                      width: (months.length * 44).toDouble().clamp(320, double.infinity),
                      child: _HistoryChart(months: months),
                    ),
                  ),
                ),
              ),
              const SizedBox(height: 16),
              SectionCard(
                title: 'Помесячно',
                child: _HistoryTable(rows: data.rows),
              ),
            ],
          );
        },
      ),
    );
  }
}

class _PeriodChips extends ConsumerWidget {
  const _PeriodChips();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final months = ref.watch(historyMonthsProvider);
    return Wrap(
      spacing: 8,
      children: [
        for (final m in const [12, 24, 36, 120])
          ChoiceChip(
            label: Text(m >= 120 ? 'Всё время' : '$m мес'),
            selected: months == m,
            onSelected: (_) => ref.read(historyMonthsProvider.notifier).state = m,
          ),
      ],
    );
  }
}

/// One bar per month, in rubles. Rows of several kinds inside a month are summed for the
/// chart; the breakdown by kind stays in the table below.
class _MonthTotal {
  _MonthTotal(this.month, this.amountRub);
  final DateTime month;
  final Decimal amountRub;
}

List<_MonthTotal> _byMonth(List<IncomeHistoryRow> rows) {
  final sums = <DateTime, Decimal>{};
  for (final r in rows) {
    final m = r.month;
    if (m == null) continue;
    final key = DateTime.utc(m.year, m.month);
    sums[key] = (sums[key] ?? Decimal.zero) + (Decimal.tryParse(r.amountRub ?? '') ?? Decimal.zero);
  }
  final keys = sums.keys.toList()..sort();
  return [for (final k in keys) _MonthTotal(k, sums[k]!)];
}

class _HistoryChart extends StatelessWidget {
  const _HistoryChart({required this.months});

  final List<_MonthTotal> months;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final maxY = months.fold<double>(0, (m, r) {
      final v = r.amountRub.toDouble();
      return v > m ? v : m;
    });
    return BarChart(
      BarChartData(
        maxY: maxY == 0 ? 1 : maxY * 1.15,
        gridData: const FlGridData(show: true, drawVerticalLine: false),
        borderData: FlBorderData(show: false),
        titlesData: FlTitlesData(
          topTitles: const AxisTitles(),
          rightTitles: const AxisTitles(),
          leftTitles: const AxisTitles(
            sideTitles: SideTitles(showTitles: true, reservedSize: 56),
          ),
          bottomTitles: AxisTitles(
            sideTitles: SideTitles(
              showTitles: true,
              reservedSize: 28,
              getTitlesWidget: (value, meta) {
                final i = value.round();
                if (i < 0 || i >= months.length) return const SizedBox.shrink();
                if (months.length > 14 && i % 3 != 0) return const SizedBox.shrink();
                return Text(ruMonthYearShort(months[i].month), style: theme.textTheme.bodySmall);
              },
            ),
          ),
        ),
        barTouchData: BarTouchData(
          touchTooltipData: BarTouchTooltipData(
            getTooltipItem: (group, _, rod, _) => BarTooltipItem(
              '${ruMonthYearShort(months[group.x].month)}\n'
              '${MoneyText.format(months[group.x].amountRub.toString(), 'RUB')}',
              theme.textTheme.bodySmall ?? const TextStyle(),
            ),
          ),
        ),
        barGroups: [
          for (var i = 0; i < months.length; i++)
            BarChartGroupData(
              x: i,
              barRods: [
                BarChartRodData(
                  toY: months[i].amountRub.toDouble(),
                  color: basisColor('paid'),
                  width: 12,
                  borderRadius: const BorderRadius.vertical(top: Radius.circular(2)),
                ),
              ],
            ),
        ],
      ),
    );
  }
}

class _HistoryTable extends StatelessWidget {
  const _HistoryTable({required this.rows});

  final List<IncomeHistoryRow> rows;

  @override
  Widget build(BuildContext context) {
    final headerStyle = Theme.of(context).textTheme.labelMedium;
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: DataTable(
        columns: [
          DataColumn(label: Text('Месяц', style: headerStyle)),
          DataColumn(label: Text('Тип', style: headerStyle)),
          DataColumn(label: Text('Валюта', style: headerStyle)),
          DataColumn(label: Text('Сумма', style: headerStyle), numeric: true),
          DataColumn(label: Text('В рублях', style: headerStyle), numeric: true),
          DataColumn(label: Text('Налог', style: headerStyle), numeric: true),
          DataColumn(label: Text('Выплат', style: headerStyle), numeric: true),
        ],
        rows: [
          for (final r in rows)
            DataRow(
              cells: [
                DataCell(Text(r.month == null ? '—' : ruMonthYearShort(r.month!))),
                DataCell(Text(incomeKindLabel(r.kind))),
                DataCell(Text(r.currency)),
                DataCell(MoneyText(r.amount, currency: r.currency)),
                DataCell(r.amountRub == null
                    ? const Text('—')
                    : MoneyText(r.amountRub!, currency: 'RUB')),
                DataCell(r.taxWithheld == null
                    ? const Text('—')
                    : MoneyText(r.taxWithheld!, currency: r.currency)),
                DataCell(Text('${r.paymentCount}')),
              ],
            ),
        ],
      ),
    );
  }
}