fin-tracker/app/lib/features/tax/lots_tab.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.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 '../portfolio/labels.dart' show formatQty, signColor;
import 'data/tax_api.dart';
import 'providers.dart';

/// Лоты и ЛДВ: the practical screen of the phase — what a sale costs **today** versus what
/// it costs after the three-year mark.
///
/// Lots close to the ЛДВ date are called out, because selling a lot 20 days early is the
/// one mistake this screen exists to prevent.
class TaxLotsTab extends ConsumerStatefulWidget {
  const TaxLotsTab({super.key});

  @override
  ConsumerState<TaxLotsTab> createState() => _TaxLotsTabState();
}

class _TaxLotsTabState extends ConsumerState<TaxLotsTab> {
  bool _onlyNearLdv = false;

  @override
  Widget build(BuildContext context) {
    final lots = ref.watch(taxLotsProvider);

    return RefreshIndicator(
      onRefresh: () async => ref.invalidate(taxLotsProvider),
      child: AsyncValueView(
        value: lots,
        onRetry: () => ref.invalidate(taxLotsProvider),
        data: (cached) {
          final all = cached.data;
          final near = all.where((l) => l.nearLdv).toList();
          // a copy: the provider's list must not be reordered under other watchers
          final rows = [...(_onlyNearLdv ? near : all)];
          // soonest ЛДВ first among the lots that do not have it yet, eligible ones last
          rows.sort((a, b) {
            if (a.ldvEligible != b.ldvEligible) return a.ldvEligible ? 1 : -1;
            return (a.daysToLdv ?? 1 << 30).compareTo(b.daysToLdv ?? 1 << 30);
          });

          if (all.isEmpty) {
            return ListView(
              padding: const EdgeInsets.all(16),
              children: const [
                SizedBox(height: 48),
                EmptyState(
                  icon: Icons.inventory_2_outlined,
                  message: 'Открытых лотов нет.',
                ),
              ],
            );
          }

          return ListView(
            padding: const EdgeInsets.all(16),
            children: [
              if (near.isNotEmpty)
                Card(
                  color: Theme.of(context).colorScheme.tertiaryContainer,
                  child: ListTile(
                    leading: const Icon(Icons.schedule),
                    title: Text('До ЛДВ меньше полугода: ${near.length} лот(ов)'),
                    subtitle: const Text(
                        'Продажа до этой даты облагается налогом на весь прирост.'),
                    trailing: FilterChip(
                      label: const Text('только они'),
                      selected: _onlyNearLdv,
                      onSelected: (v) => setState(() => _onlyNearLdv = v),
                    ),
                  ),
                ),
              const SizedBox(height: 12),
              SectionCard(
                title: 'Открытые лоты',
                subtitle: 'налог при продаже сегодня — оценка по ставке из сводки',
                child: _LotsTable(rows: rows),
              ),
            ],
          );
        },
      ),
    );
  }
}

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

  final List<TaxLot> rows;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final headerStyle = theme.textTheme.labelMedium;
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: DataTable(
        columns: [
          DataColumn(label: Text('Бумага', style: headerStyle)),
          DataColumn(label: Text('Куплен', style: headerStyle)),
          DataColumn(label: Text('Кол-во', style: headerStyle), numeric: true),
          DataColumn(label: Text('Стоимость', style: headerStyle), numeric: true),
          DataColumn(label: Text('Рынок', style: headerStyle), numeric: true),
          DataColumn(label: Text('Нереализ.', style: headerStyle), numeric: true),
          DataColumn(label: Text('Дата ЛДВ', style: headerStyle)),
          DataColumn(label: Text('Дней до ЛДВ', style: headerStyle), numeric: true),
          DataColumn(label: Text('Налог при продаже', style: headerStyle), numeric: true),
        ],
        rows: [
          for (final l in rows)
            DataRow(
              color: l.nearLdv
                  ? WidgetStatePropertyAll(
                      theme.colorScheme.tertiaryContainer.withValues(alpha: 0.5))
                  : null,
              onSelectChanged: l.instrumentId == null
                  ? null
                  : (_) => context.push('/portfolio/instrument/${l.instrumentId}'),
              cells: [
                DataCell(Row(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Text(l.title),
                    if (l.nearLdv) ...[
                      const SizedBox(width: 6),
                      Tooltip(
                        message: 'До ЛДВ осталось ${l.daysToLdv} дн. — '
                            'продажа сейчас облагается налогом полностью',
                        child: Icon(Icons.schedule, size: 16, color: theme.colorScheme.error),
                      ),
                    ],
                  ],
                )),
                DataCell(Text(l.openDate == null ? '—' : ruDate(l.openDate!))),
                DataCell(Text(l.qtyRemaining == null ? '—' : formatQty(l.qtyRemaining!))),
                DataCell(l.costRub == null
                    ? const Text('—')
                    : MoneyText(l.costRub!, currency: 'RUB')),
                DataCell(l.marketValueRub == null
                    ? const Text('—')
                    : MoneyText(l.marketValueRub!, currency: 'RUB')),
                DataCell(l.unrealizedGainRub == null
                    ? const Text('—')
                    : MoneyText(
                        l.unrealizedGainRub!,
                        currency: 'RUB',
                        style: TextStyle(color: signColor(context, l.unrealizedGainRub)),
                      )),
                DataCell(l.ldvEligible
                    ? const Text('уже действует')
                    : Text(l.ldvDate == null ? '—' : ruDate(l.ldvDate!))),
                DataCell(l.ldvEligible
                    ? const Text('—')
                    : Text(
                        l.daysToLdv == null ? '—' : '${l.daysToLdv}',
                        style: l.nearLdv
                            ? TextStyle(
                                color: theme.colorScheme.error, fontWeight: FontWeight.w600)
                            : null,
                      )),
                DataCell(l.taxIfSoldNowRub == null
                    ? const Text('—')
                    : MoneyText(l.taxIfSoldNowRub!, currency: 'RUB')),
              ],
            ),
        ],
      ),
    );
  }
}