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

import '../../core/api/api_client.dart';
import '../../core/auth/auth_controller.dart';
import '../../core/theme/chart_colors.dart';
import '../../core/utils/ru_date.dart';
import '../../core/widgets/async_value_view.dart';
import '../../core/widgets/asset_icon.dart';
import '../../core/widgets/empty_state.dart';
import '../../core/widgets/money_text.dart';
import '../../core/widgets/stale_banner.dart';
import '../../core/widgets/help_tip.dart';
import 'instrument_edit_dialog.dart';
import 'labels.dart';
import 'providers.dart';

double _d(String s) => Decimal.parse(s).toDouble();

/// The instrument card: the position, the lots behind its cost, every event that touched it
/// and the price history behind its value — the screen that answers "where does this number
/// come from" when a reconciliation finding points here.
class InstrumentPage extends ConsumerWidget {
  const InstrumentPage({required this.instrumentId, super.key});

  final int instrumentId;

  Future<void> _edit(
    BuildContext context,
    WidgetRef ref,
    InstrumentOut instrument,
  ) async {
    final patch = await showDialog<InstrumentPatch>(
      context: context,
      builder: (_) => InstrumentEditDialog(instrument: instrument),
    );
    if (patch == null || !context.mounted) return;
    final messenger = ScaffoldMessenger.of(context);
    try {
      final api = ref.read(apiProvider);
      await api.getInstrumentsApi().instrumentsPatch(
        instrumentId: instrumentId,
        instrumentPatch: patch,
      );
      invalidatePortfolioProviders(ref);
      try {
        // the asset class feeds the allocation metrics; the lot only the live rebalancing
        await api.getMetricsApi().metricsRefresh();
      } on DioException {
        // the next scheduled or manual refresh picks the change up
      }
    } on DioException catch (e) {
      messenger.showSnackBar(SnackBar(content: Text(problemMessage(e))));
    }
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final detail = ref.watch(instrumentProvider(instrumentId));
    final instrument = detail.valueOrNull?.data.instrument;

    return Scaffold(
      appBar: AppBar(
        title: Text(instrument?.ticker ?? instrument?.name ?? 'Инструмент'),
        actions: [
          if (instrument != null)
            IconButton(
              tooltip: 'Редактировать',
              icon: const Icon(Icons.edit_outlined),
              onPressed: () => _edit(context, ref, instrument),
            ),
        ],
      ),
      body: AsyncValueView(
        value: detail,
        onRetry: () => ref.invalidate(instrumentProvider(instrumentId)),
        data: (cached) {
          final d = cached.data;
          return ListView(
            padding: const EdgeInsets.all(16),
            children: [
              if (cached.fetchedAt != null)
                StaleBanner(fetchedAt: cached.fetchedAt!),
              _Header(instrument: d.instrument, holding: d.holding),
              const SizedBox(height: 16),
              _Section(
                title: 'Цена',
                child: d.prices.isEmpty
                    ? const EmptyState(
                        icon: Icons.show_chart,
                        message: 'Цен нет — стоимость позиции неизвестна.',
                      )
                    : _PriceChart(prices: d.prices),
              ),
              const SizedBox(height: 16),
              _Section(
                title: 'Лоты',
                child: d.lots.isEmpty
                    ? const EmptyState(
                        icon: Icons.layers_outlined,
                        message: 'Лотов нет.',
                      )
                    : _LotsTable(lots: d.lots),
              ),
              const SizedBox(height: 16),
              _Section(
                title: 'События',
                child: d.events.isEmpty
                    ? const EmptyState(
                        icon: Icons.receipt_long,
                        message: 'Событий нет.',
                      )
                    : _EventsTable(events: d.events),
              ),
            ],
          );
        },
      ),
    );
  }
}

class _Header extends StatelessWidget {
  const _Header({required this.instrument, required this.holding});

  final InstrumentOut instrument;
  final HoldingOut? holding;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final facts = <String>[
      assetClassLabel(instrument.assetClass),
      if (instrument.board != null) instrument.board!,
      if (instrument.isin != null) instrument.isin!,
      if (instrument.country != null) instrument.country!,
      instrument.currency,
    ];
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                AssetIcon(
                  assetClass: instrument.assetClass,
                  logoUrl: instrument.logoUrl,
                  logoColor: instrument.logoColor,
                  size: 48,
                ),
                const SizedBox(width: 16),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(instrument.name, style: theme.textTheme.titleLarge),
                      const SizedBox(height: 4),
                      Text(
                        facts.join(' · '),
                        style: theme.textTheme.bodySmall?.copyWith(
                          color: theme.hintColor,
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ),
            const SizedBox(height: 16),
            if (holding == null)
              Text('Позиция закрыта', style: theme.textTheme.bodyMedium)
            else
              _HoldingFacts(holding: holding!),
          ],
        ),
      ),
    );
  }
}

class _HoldingFacts extends StatelessWidget {
  const _HoldingFacts({required this.holding});

  final HoldingOut holding;

  @override
  Widget build(BuildContext context) {
    final h = holding;
    return Wrap(
      spacing: 24,
      runSpacing: 12,
      children: [
        _Fact(label: 'Количество', value: Text(formatQty(h.qty))),
        _Fact(
          label: 'Средняя цена',
          value: h.avgCost == null
              ? const Text('—')
              : MoneyText(h.avgCost!, currency: h.costCurrency ?? h.currency),
        ),
        _Fact(
          label: 'Текущая цена',
          value: Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              h.marketPrice == null
                  ? const Text('—')
                  : MoneyText(
                      h.marketPrice!,
                      currency: h.priceCurrency ?? h.currency,
                    ),
              const SizedBox(width: 6),
              PriceStatusChip(status: h.priceStatus, priceDate: h.priceDate),
            ],
          ),
        ),
        _Fact(
          label: 'Стоимость',
          value: h.valueRub == null
              ? const Text('—')
              : MoneyText(h.valueRub!, currency: 'RUB'),
        ),
        _Fact(
          label: 'Нереализованная',
          value: h.unrealizedPnlRub == null
              ? const Text('—')
              : MoneyText(
                  h.unrealizedPnlRub!,
                  currency: 'RUB',
                  style: TextStyle(
                    color: signColor(context, h.unrealizedPnlRub),
                  ),
                ),
        ),
        _Fact(
          label: 'Реализованная',
          value: MoneyText(h.realizedPnlRub ?? '0', currency: 'RUB'),
        ),
        _Fact(
          label: 'Выплаты',
          value: MoneyText(h.incomeRub ?? '0', currency: 'RUB'),
        ),
        _Fact(
          label: 'XIRR',
          value: Text(
            formatPercent(h.xirr),
            style: TextStyle(color: signColor(context, h.xirr)),
          ),
        ),
        if (h.firstBuyDate != null)
          _Fact(
            label: 'В портфеле',
            value: Text('${h.daysHeld ?? 0} дн. с ${ruDate(h.firstBuyDate!)}'),
          ),
        if (_d(h.ldvEligibleQty) > 0)
          _Fact(label: 'Под ЛДВ', value: Text(formatQty(h.ldvEligibleQty))),
      ],
    );
  }
}

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

  final String label;
  final Widget value;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        TermLabel(
          label,
          style: theme.textTheme.bodySmall?.copyWith(color: theme.hintColor),
        ),
        const SizedBox(height: 2),
        DefaultTextStyle(style: theme.textTheme.titleSmall!, child: value),
      ],
    );
  }
}

class _PriceChart extends StatelessWidget {
  const _PriceChart({required this.prices});

  final List<PricePoint> prices;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return SizedBox(
      height: 200,
      child: LineChart(
        LineChartData(
          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: 52),
            ),
            bottomTitles: AxisTitles(
              sideTitles: SideTitles(
                showTitles: true,
                reservedSize: 28,
                interval: (prices.length / 4).clamp(1, double.infinity),
                getTitlesWidget: (value, meta) {
                  final i = value.round();
                  if (i < 0 || i >= prices.length)
                    return const SizedBox.shrink();
                  return Text(
                    ruMonthYearShort(prices[i].d),
                    style: theme.textTheme.bodySmall,
                  );
                },
              ),
            ),
          ),
          lineBarsData: [
            LineChartBarData(
              spots: [
                for (var i = 0; i < prices.length; i++)
                  FlSpot(i.toDouble(), _d(prices[i].close)),
              ],
              isCurved: false,
              color: ChartColors.slot1Blue,
              barWidth: 2,
              dotData: FlDotData(show: prices.length < 2),
            ),
          ],
        ),
      ),
    );
  }
}

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

  final List<LotOut> lots;

  @override
  Widget build(BuildContext context) {
    final headerStyle = Theme.of(context).textTheme.labelMedium;
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: DataTable(
        columns: [
          DataColumn(label: Text('Открыт', style: headerStyle)),
          DataColumn(label: Text('Куплено', style: headerStyle), numeric: true),
          DataColumn(
            label: Text('Осталось', style: headerStyle),
            numeric: true,
          ),
          DataColumn(label: Text('Цена', style: headerStyle), numeric: true),
          DataColumn(
            label: Text('Стоимость, ₽', style: headerStyle),
            numeric: true,
          ),
          DataColumn(label: Text('Закрыт', style: headerStyle)),
        ],
        rows: [
          for (final lot in lots)
            DataRow(
              cells: [
                DataCell(Text(ruDate(lot.openDate))),
                DataCell(Text(formatQty(lot.qtyOpen))),
                DataCell(Text(formatQty(lot.qtyRemaining))),
                DataCell(
                  MoneyText(lot.costPerUnit, currency: lot.costCurrency),
                ),
                DataCell(
                  lot.costTotalRub == null
                      ? const Text('—')
                      : MoneyText(lot.costTotalRub!, currency: 'RUB'),
                ),
                DataCell(
                  Text(lot.closedAt == null ? '—' : ruDate(lot.closedAt!)),
                ),
              ],
            ),
        ],
      ),
    );
  }
}

class _EventsTable extends StatelessWidget {
  const _EventsTable({required this.events});

  final List<EventOut> events;

  @override
  Widget build(BuildContext context) {
    final headerStyle = Theme.of(context).textTheme.labelMedium;
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: DataTable(
        columns: [
          DataColumn(label: Text('Дата', style: headerStyle)),
          DataColumn(label: Text('Тип', style: headerStyle)),
          DataColumn(label: Text('Кол-во', style: headerStyle), numeric: true),
          DataColumn(label: Text('Цена', style: headerStyle), numeric: true),
          DataColumn(label: Text('Сумма', style: headerStyle), numeric: true),
          DataColumn(label: Text('Описание', style: headerStyle)),
        ],
        rows: [
          for (final e in events)
            DataRow(
              cells: [
                DataCell(Text(ruDate(e.tradeDate))),
                DataCell(
                  Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text(eventKindLabel(e.kind)),
                      if (e.externalFlow) ...[
                        const SizedBox(width: 4),
                        const Tooltip(
                          message: 'Внешний поток — учитывается в XIRR',
                          child: Icon(Icons.swap_vert, size: 14),
                        ),
                      ],
                    ],
                  ),
                ),
                DataCell(
                  Text(e.quantity == null ? '—' : formatQty(e.quantity!)),
                ),
                DataCell(
                  e.price == null
                      ? const Text('—')
                      : MoneyText(
                          e.price!,
                          currency: e.priceCurrency ?? e.currency,
                        ),
                ),
                DataCell(
                  MoneyText(
                    e.amount,
                    currency: e.currency,
                    style: TextStyle(color: signColor(context, e.amount)),
                  ),
                ),
                DataCell(
                  SizedBox(
                    width: 260,
                    child: Text(
                      e.description ?? '',
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                ),
              ],
            ),
        ],
      ),
    );
  }
}

class _Section extends StatelessWidget {
  const _Section({required this.title, required this.child});

  final String title;
  final Widget child;

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(title, style: Theme.of(context).textTheme.titleMedium),
            const SizedBox(height: 12),
            child,
          ],
        ),
      ),
    );
  }
}