import 'package:decimal/decimal.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/theme/chart_colors.dart';
import '../../core/utils/compact_number.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/help_tip.dart';
import 'benchmarks_card.dart';
import 'holdings_table.dart';
import 'labels.dart';
import 'providers.dart';

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

/// Which parts of the screen a [HoldingsTab] draws. The same providers feed all of them, so
/// the numbers on Портфель and on Аналитика → Общее can never disagree.
enum HoldingsSections {
  /// Everything, top to bottom.
  all,

  /// Only the assets table — the Портфель screen.
  table,

  /// The charts and returns, without the table — Аналитика → Общее.
  overview,
}

/// Позиции: what the portfolio holds, what it is worth, and what it earned.
class HoldingsTab extends ConsumerWidget {
  const HoldingsTab({
    this.sections = HoldingsSections.all,
    this.header,
    super.key,
  });

  final HoldingsSections sections;

  /// Drawn above everything else, inside the same scrolling list.
  final Widget? header;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final summary = ref.watch(portfolioSummaryProvider);
    final holdings = ref.watch(holdingsProvider);
    final series = ref.watch(valueSeriesProvider);
    final returns = ref.watch(portfolioReturnsProvider);
    final all = sections == HoldingsSections.all;
    final withTable = all || sections == HoldingsSections.table;
    final withCharts = all || sections == HoldingsSections.overview;

    return RefreshIndicator(
      onRefresh: () async => invalidatePortfolioProviders(ref),
      child: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          if (header != null) ...[header!, const SizedBox(height: 16)],
          if (all) ...[
            AsyncValueView(
              value: summary,
              onRetry: () => ref.invalidate(portfolioSummaryProvider),
              data: (cached) => _SummaryTiles(summary: cached.data),
            ),
            const SizedBox(height: 20),
          ],
          if (withCharts) ...[
            _Card(
              title: 'Стоимость за 365 дней',
              child: AsyncValueView(
                value: series,
                onRetry: () => ref.invalidate(valueSeriesProvider),
                data: (cached) => cached.data.isEmpty
                    ? const EmptyState(
                        icon: Icons.show_chart,
                        message: 'Пока нет данных.',
                      )
                    : _ValueChart(rows: cached.data),
              ),
            ),
            const SizedBox(height: 16),
            _Card(
              title: 'Доходность',
              child: AsyncValueView(
                value: returns,
                onRetry: () => ref.invalidate(portfolioReturnsProvider),
                data: (cached) => cached.data.isEmpty
                    ? const EmptyState(
                        icon: Icons.percent,
                        message: 'Пока нечего считать.',
                      )
                    : _ReturnsTable(rows: cached.data),
              ),
            ),
            const SizedBox(height: 16),
            const _Card(
              title: 'Сравнение с бенчмарками',
              child: BenchmarksCard(),
            ),
          ],
          if (withTable && withCharts) const SizedBox(height: 16),
          if (withTable)
            _Card(
              title: all ? 'Позиции' : null,
              child: AsyncValueView(
                value: holdings,
                onRetry: () => ref.invalidate(holdingsProvider),
                data: (cached) => cached.data.isEmpty
                    ? const EmptyState(
                        icon: Icons.inventory_2_outlined,
                        message: 'Открытых позиций нет — нужна синхронизация брокера.',
                      )
                    : HoldingsTable(rows: cached.data),
              ),
            ),
        ],
      ),
    );
  }
}

class _SummaryTiles extends StatelessWidget {
  const _SummaryTiles({required this.summary});

  final SummaryOut summary;

  @override
  Widget build(BuildContext context) {
    final yearly = summary.returns.where((r) => r.period == '1y').firstOrNull;
    return Wrap(
      spacing: 12,
      runSpacing: 12,
      children: [
        _Tile(
          label: 'Стоимость',
          value: MoneyText(summary.totalRub, currency: 'RUB'),
          note: 'в т.ч. кэш ${MoneyText.format(summary.cashRub, 'RUB')}',
        ),
        _Tile(
          label: 'Вложено',
          value: MoneyText(summary.investedNetRub, currency: 'RUB'),
          note: 'внешние потоки нетто',
        ),
        _Tile(
          label: 'Прибыль',
          value: summary.pnlTotalRub == null
              ? const Text('—')
              : MoneyText(
                  summary.pnlTotalRub!,
                  currency: 'RUB',
                  style: TextStyle(
                    color: signColor(context, summary.pnlTotalRub),
                  ),
                ),
          note: summary.pnlTotalRub == null
              ? 'часть позиций без цены'
              : 'реализовано ${MoneyText.format(summary.realizedPnlRub, 'RUB')}',
        ),
        _Tile(
          label: 'Выплаты',
          value: MoneyText(summary.incomeRub, currency: 'RUB'),
          note: 'дивиденды и купоны',
        ),
        _Tile(
          label: 'XIRR, год',
          value: Text(
            formatPercent(yearly?.xirr),
            style: TextStyle(color: signColor(context, yearly?.xirr)),
          ),
          note: 'денежно-взвешенная',
        ),
        _Tile(
          label: 'TWR, год',
          value: Text(
            formatPercent(yearly?.twr),
            style: TextStyle(color: signColor(context, yearly?.twr)),
          ),
          note: (yearly?.twrDaysSkipped ?? 0) > 0
              ? 'пропущено ${yearly!.twrDaysSkipped} дн.'
              : 'без учёта пополнений',
        ),
        if (summary.unpricedCount > 0 || summary.staleCount > 0)
          _Tile(
            label: 'Цены',
            value: Text('${summary.unpricedCount} / ${summary.staleCount}'),
            note: 'без цены / устаревших',
          ),
      ],
    );
  }
}

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

  final String label;
  final Widget value;
  final String? note;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return SizedBox(
      width: 184,
      child: Card(
        child: Padding(
          padding: const EdgeInsets.all(12),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              TermLabel(label, style: theme.textTheme.bodySmall),
              const SizedBox(height: 4),
              DefaultTextStyle(
                style: theme.textTheme.titleMedium!,
                child: value,
              ),
              if (note != null) ...[
                const SizedBox(height: 2),
                Text(
                  note!,
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: theme.hintColor,
                  ),
                  maxLines: 2,
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}

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

  final List<ValueDay> rows;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final spots = <FlSpot>[];
    final invested = <FlSpot>[];
    for (var i = 0; i < rows.length; i++) {
      spots.add(FlSpot(i.toDouble(), _d(rows[i].totalRub)));
      invested.add(FlSpot(i.toDouble(), _d(rows[i].investedNetRub)));
    }
    const names = ['Стоимость', 'Вложено (нетто)'];
    final chart = SizedBox(
      height: 220,
      child: LineChart(
        LineChartData(
          gridData: const FlGridData(show: true, drawVerticalLine: false),
          borderData: FlBorderData(show: false),
          titlesData: FlTitlesData(
            topTitles: const AxisTitles(),
            rightTitles: const AxisTitles(),
            leftTitles: AxisTitles(
              sideTitles: SideTitles(
                showTitles: true,
                reservedSize: 56,
                getTitlesWidget: (value, meta) {
                  // the axis ends sit on the data's min/max and land on top of the round
                  // labels next to them (414,6 тыс over 400 тыс)
                  if (value == meta.min || value == meta.max) {
                    return const SizedBox.shrink();
                  }
                  return SideTitleWidget(
                    axisSide: meta.axisSide,
                    child: Text(
                      compactNumber(value),
                      style: theme.textTheme.bodySmall,
                    ),
                  );
                },
              ),
            ),
            bottomTitles: AxisTitles(
              sideTitles: SideTitles(
                showTitles: true,
                reservedSize: 28,
                // ticks at the quarters of the span, so the last one is the last day
                interval: ((rows.length - 1) / 4).clamp(1.0, double.infinity),
                getTitlesWidget: (value, meta) {
                  // float steps can land a label a hair before the last one; keep only one
                  if (value != meta.max &&
                      meta.max - value < meta.appliedInterval * 0.1) {
                    return const SizedBox.shrink();
                  }
                  final i = value.round();
                  if (i < 0 || i >= rows.length) return const SizedBox.shrink();
                  return SideTitleWidget(
                    axisSide: meta.axisSide,
                    fitInside: SideTitleFitInsideData.fromTitleMeta(meta),
                    child: Text(
                      ruMonthYearShort(rows[i].d),
                      style: theme.textTheme.bodySmall,
                    ),
                  );
                },
              ),
            ),
          ),
          lineBarsData: [
            LineChartBarData(
              spots: spots,
              isCurved: false,
              color: ChartColors.slot1Blue,
              barWidth: 2,
              dotData: const FlDotData(show: false),
            ),
            LineChartBarData(
              spots: invested,
              isCurved: false,
              color: ChartColors.slot4Yellow,
              barWidth: 1.5,
              dashArray: const [4, 3],
              dotData: const FlDotData(show: false),
            ),
          ],
          lineTouchData: LineTouchData(
            touchTooltipData: LineTouchTooltipData(
              getTooltipItems: (touched) => [
                for (final (i, t) in touched.indexed)
                  LineTooltipItem(
                    '${i == 0 ? '${ruDate(rows[t.x.round()].d)}\n' : ''}'
                    '${names[t.barIndex]}: '
                    '${MoneyText.format(t.y.toStringAsFixed(2), 'RUB')}',
                    theme.textTheme.bodySmall ?? const TextStyle(),
                  ),
              ],
            ),
          ),
        ),
      ),
    );

    // the dashed line has no other explanation: say what each of the two is
    Widget key(Color color, String label, {bool dashed = false}) => Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        SizedBox(
          width: 18,
          child: dashed
              ? Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    for (var i = 0; i < 3; i++)
                      Container(width: 4, height: 2, color: color),
                  ],
                )
              : Container(height: 2, color: color),
        ),
        const SizedBox(width: 6),
        Text(label, style: theme.textTheme.bodySmall),
      ],
    );

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        chart,
        const SizedBox(height: 8),
        Wrap(
          spacing: 16,
          runSpacing: 4,
          children: [
            key(ChartColors.slot1Blue, names[0]),
            key(ChartColors.slot4Yellow, names[1], dashed: true),
          ],
        ),
      ],
    );
  }
}

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

  final List<ReturnsOut> rows;

  @override
  Widget build(BuildContext context) {
    final headerStyle = Theme.of(context).textTheme.labelMedium;
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: DataTable(
        columns: [
          DataColumn(label: Text('Период', style: headerStyle)),
          DataColumn(
            label: TermLabel(
              'Прибыль',
              style: headerStyle,
              alignment: MainAxisAlignment.end,
            ),
            numeric: true,
          ),
          DataColumn(
            label: TermLabel(
              'Потоки',
              style: headerStyle,
              alignment: MainAxisAlignment.end,
            ),
            numeric: true,
          ),
          DataColumn(
            label: TermLabel(
              'XIRR',
              style: headerStyle,
              alignment: MainAxisAlignment.end,
            ),
            numeric: true,
          ),
          DataColumn(
            label: TermLabel(
              'TWR',
              style: headerStyle,
              alignment: MainAxisAlignment.end,
            ),
            numeric: true,
          ),
        ],
        rows: [
          for (final r in rows)
            DataRow(
              cells: [
                DataCell(Text(periodLabel(r.period))),
                DataCell(
                  MoneyText(
                    r.absPnlRub,
                    currency: 'RUB',
                    style: TextStyle(color: signColor(context, r.absPnlRub)),
                  ),
                ),
                DataCell(MoneyText(r.externalFlowRub, currency: 'RUB')),
                DataCell(
                  Text(
                    formatPercent(r.xirr),
                    style: TextStyle(color: signColor(context, r.xirr)),
                  ),
                ),
                DataCell(
                  Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text(
                        formatPercent(r.twr),
                        style: TextStyle(color: signColor(context, r.twr)),
                      ),
                      if (r.twrDaysSkipped > 0) ...[
                        const SizedBox(width: 4),
                        Tooltip(
                          message:
                              'Пропущено ${r.twrDaysSkipped} дн.: '
                              'в эти дни часть позиции была без цены',
                          child: const Icon(Icons.info_outline, size: 14),
                        ),
                      ],
                    ],
                  ),
                ),
              ],
            ),
        ],
      ),
    );
  }
}

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

  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: [
            if (title != null) ...[
              TermLabel(title!, style: Theme.of(context).textTheme.titleMedium),
              const SizedBox(height: 12),
            ],
            child,
          ],
        ),
      ),
    );
  }
}