import 'package:decimal/decimal.dart';
import 'package:fintracker_api/fintracker_api.dart';
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

import '../../core/widgets/asset_icon.dart';
import '../../core/widgets/money_text.dart';
import '../../core/widgets/help_tip.dart';
import 'labels.dart';

/// Which columns the table shows. Each preset answers one question about the same rows, the
/// way Snowball's «Мои активы | Общее | Дивиденды | Прибыль | Облигации» tabs do.
enum HoldingsPreset {
  mine('Мои активы'),
  overall('Общее'),
  dividends('Дивиденды'),
  profit('Прибыль'),
  bonds('Облигации');

  const HoldingsPreset(this.label);
  final String label;
}

/// A column: a header, a width, and how a position renders in it. A cell is one or two lines —
/// the figure and, muted below it, the same figure per unit or as a share.
class _Col {
  const _Col(this.title, this.width, this.cell, {this.alignEnd = true});

  final String title;
  final double width;
  final Widget Function(BuildContext context, HoldingOut h) cell;
  final bool alignEnd;
}

const _dash = Text('—');

/// A cell whose figure is unknown is a dash, never a zero: the position is absent from the
/// totals, and 0 ₽ would read as «worthless» instead of «unknown».
Widget _money(
  String? v, {
  String currency = 'RUB',
  TextStyle? style,
  bool signed = false,
}) {
  if (v == null) return _dash;
  final d = Decimal.parse(v);
  final text = MoneyText.format(v, currency);
  return Text(signed && d > Decimal.zero ? '+$text' : text, style: style);
}

Widget _stack(BuildContext context, Widget top, Widget? bottom) {
  final muted = Theme.of(context).textTheme.bodySmall
      ?.copyWith(color: Theme.of(context).colorScheme.onSurfaceVariant);
  return Column(
    crossAxisAlignment: CrossAxisAlignment.end,
    mainAxisSize: MainAxisSize.min,
    children: [
      DefaultTextStyle.merge(
        style: const TextStyle(fontWeight: FontWeight.w600),
        child: top,
      ),
      if (bottom != null) DefaultTextStyle.merge(style: muted, child: bottom),
    ],
  );
}

/// `share` of a decimal-string pair, or null when the base is missing or not positive.
String? _ratio(String? part, String? base) {
  if (part == null || base == null) return null;
  final b = Decimal.parse(base);
  if (b <= Decimal.zero) return null;
  return (Decimal.parse(part) / b)
      .toDecimal(scaleOnInfinitePrecision: 10)
      .toString();
}

Widget _signedPercent(BuildContext context, String? share) {
  if (share == null) return _dash;
  final color = signColor(context, share);
  final d = Decimal.parse(share);
  final arrow = d > Decimal.zero
      ? Icons.arrow_drop_up
      : d < Decimal.zero
      ? Icons.arrow_drop_down
      : null;
  return Row(
    mainAxisSize: MainAxisSize.min,
    children: [
      if (arrow != null) Icon(arrow, size: 18, color: color),
      Text(
        formatPercent(share, signed: false).replaceAll('-', ''),
        style: TextStyle(color: color),
      ),
    ],
  );
}

Widget _pnl(BuildContext context, String? amount, String? share) {
  if (amount == null) return _dash;
  return _stack(
    context,
    _money(
      amount,
      signed: true,
      style: TextStyle(color: signColor(context, amount)),
    ),
    _signedPercent(context, share),
  );
}

final _asset = _Col('Актив', 260, (context, h) {
  final theme = Theme.of(context);
  final title = h.name;
  final ticker = h.ticker;
  return Row(
    children: [
      AssetIcon(
        assetClass: h.assetClass,
        logoUrl: h.logoUrl,
        logoColor: h.logoColor,
      ),
      const SizedBox(width: 12),
      Expanded(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              title,
              overflow: TextOverflow.ellipsis,
              style: const TextStyle(fontWeight: FontWeight.w500),
            ),
            Row(
              children: [
                if (ticker != null && ticker != title)
                  Flexible(
                    child: Text(
                      ticker,
                      overflow: TextOverflow.ellipsis,
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                  ),
                PriceStatusChip(status: h.priceStatus, priceDate: h.priceDate),
              ],
            ),
          ],
        ),
      ),
    ],
  );
}, alignEnd: false);

final _qty = _Col('Кол-во', 90, (c, h) => Text(formatQty(h.qty)));

final _invested = _Col(
  'Вложено',
  140,
  (c, h) => _stack(
    c,
    _money(h.costTotalRub),
    h.avgCost == null
        ? null
        : _money(h.avgCost, currency: h.costCurrency ?? h.currency),
  ),
);

final _value = _Col(
  'Текущая стоимость',
  170,
  (c, h) => h.valueRub == null
      ? _dash
      : _stack(
          c,
          _money(h.valueRub),
          h.marketPrice == null
              ? null
              : _money(h.marketPrice, currency: h.priceCurrency ?? h.currency),
        ),
);

final _income = _Col('Дивиденды', 120, (c, h) => _money(_nonZero(h.incomeRub)));

final _incomeYield = _Col(
  'Див. доходность',
  130,
  (c, h) => Text(
    formatPercent(_nonZero(_ratio(h.incomeRub, h.costTotalRub)), signed: false),
  ),
);

final _profit = _Col(
  'Прибыль',
  130,
  (c, h) =>
      _pnl(c, h.unrealizedPnlRub, _ratio(h.unrealizedPnlRub, h.costTotalRub)),
);

final _weight = _Col(
  'Доля в портфеле',
  130,
  (c, h) => Text(formatPercent(h.weight, signed: false)),
);

final _xirr = _Col(
  'Доходность',
  120,
  (c, h) => Text(
    formatPercent(h.xirr),
    style: TextStyle(color: signColor(c, h.xirr)),
  ),
);

final _held = _Col(
  'В портфеле',
  120,
  (c, h) => Text(h.daysHeld == null ? '—' : '${h.daysHeld} дн.'),
);

final _realized = _Col(
  'Реализовано',
  130,
  (c, h) => _money(
    h.realizedPnlRub,
    signed: true,
    style: TextStyle(color: signColor(c, h.realizedPnlRub)),
  ),
);

final _accrued = _Col(
  'НКД',
  110,
  (c, h) => _money(_nonZero(h.accruedInterestRub)),
);

/// A payout or accrual of zero is «none», shown as a dash; only a real amount is a figure.
String? _nonZero(String? v) =>
    v == null || Decimal.parse(v) == Decimal.zero ? null : v;

final _columns = {
  HoldingsPreset.mine: [
    _asset,
    _qty,
    _invested,
    _value,
    _income,
    _incomeYield,
    _profit,
    _weight,
  ],
  HoldingsPreset.overall: [
    _asset,
    _qty,
    _invested,
    _value,
    _profit,
    _xirr,
    _weight,
    _held,
  ],
  HoldingsPreset.dividends: [_asset, _qty, _income, _incomeYield],
  HoldingsPreset.profit: [_asset, _profit, _realized, _income, _xirr],
  HoldingsPreset.bonds: [
    _asset,
    _qty,
    _invested,
    _value,
    _accrued,
    _profit,
    _xirr,
  ],
};

/// Позиции as a table: preset tabs, a search box, and one row per holding. A tap opens the
/// instrument card.
class HoldingsTable extends StatefulWidget {
  const HoldingsTable({required this.rows, super.key});

  final List<HoldingOut> rows;

  @override
  State<HoldingsTable> createState() => _HoldingsTableState();
}

class _HoldingsTableState extends State<HoldingsTable> {
  HoldingsPreset _preset = HoldingsPreset.mine;
  String _query = '';

  List<HoldingOut> get _visible {
    final q = _query.trim().toLowerCase();
    return [
      for (final h in widget.rows)
        if ((_preset != HoldingsPreset.bonds || h.assetClass == 'bond') &&
            (q.isEmpty ||
                h.name.toLowerCase().contains(q) ||
                (h.ticker ?? '').toLowerCase().contains(q)))
          h,
    ];
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final scheme = theme.colorScheme;
    final columns = _columns[_preset]!;
    final rows = _visible;
    const pad = 32.0;
    final natural = columns.fold<double>(0, (sum, c) => sum + c.width);

    return LayoutBuilder(
      builder: (context, constraints) {
        // spread the columns over the card when there is room; scroll sideways when there is not
        final room = constraints.maxWidth.isFinite
            ? constraints.maxWidth - pad
            : natural;
        final scale = room > natural ? room / natural : 1.0;
        final tableWidth = natural * scale + pad;

        return Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            SizedBox(
              width: double.infinity,
              child: Wrap(
                spacing: 12,
                runSpacing: 12,
                crossAxisAlignment: WrapCrossAlignment.center,
                alignment: WrapAlignment.spaceBetween,
                children: [
                  Wrap(
                    crossAxisAlignment: WrapCrossAlignment.center,
                    children: [
                      for (final p in HoldingsPreset.values)
                        InkWell(
                          borderRadius: BorderRadius.circular(6),
                          onTap: () => setState(() => _preset = p),
                          child: Padding(
                            padding: const EdgeInsets.symmetric(
                              horizontal: 10,
                              vertical: 6,
                            ),
                            child: Text(
                              p.label,
                              style: TextStyle(
                                color: p == _preset
                                    ? scheme.onSurface
                                    : scheme.onSurfaceVariant,
                                fontWeight: p == _preset
                                    ? FontWeight.w700
                                    : FontWeight.w400,
                              ),
                            ),
                          ),
                        ),
                    ],
                  ),
                  SizedBox(
                    width: 260,
                    child: TextField(
                      onChanged: (v) => setState(() => _query = v),
                      decoration: const InputDecoration(
                        hintText: 'Найти…',
                        isDense: true,
                        prefixIcon: Icon(Icons.search, size: 20),
                      ),
                    ),
                  ),
                ],
              ),
            ),
            const SizedBox(height: 12),
            SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              child: SizedBox(
                width: tableWidth,
                child: Column(
                  children: [
                    _HeaderRow(columns: columns, scale: scale),
                    Divider(color: scheme.outlineVariant),
                    if (rows.isEmpty)
                      const Padding(
                        padding: EdgeInsets.symmetric(vertical: 24),
                        child: Text('Ничего не найдено'),
                      ),
                    for (final h in rows)
                      InkWell(
                        onTap: () => context.push(
                          '/portfolio/instrument/${h.instrumentId}',
                        ),
                        child: Container(
                          padding: const EdgeInsets.symmetric(
                            horizontal: 16,
                            vertical: 12,
                          ),
                          decoration: BoxDecoration(
                            border: Border(
                              bottom: BorderSide(color: scheme.outlineVariant),
                            ),
                          ),
                          child: Row(
                            children: [
                              for (final c in columns)
                                SizedBox(
                                  width: c.width * scale,
                                  child: Align(
                                    alignment: c.alignEnd
                                        ? Alignment.centerRight
                                        : Alignment.centerLeft,
                                    child: Padding(
                                      padding: EdgeInsets.only(
                                        right: c.alignEnd ? 8 : 0,
                                      ),
                                      child: c.cell(context, h),
                                    ),
                                  ),
                                ),
                            ],
                          ),
                        ),
                      ),
                  ],
                ),
              ),
            ),
          ],
        );
      },
    );
  }
}

class _HeaderRow extends StatelessWidget {
  const _HeaderRow({required this.columns, required this.scale});

  final List<_Col> columns;
  final double scale;

  @override
  Widget build(BuildContext context) {
    final style = Theme.of(context).textTheme.labelMedium
        ?.copyWith(color: Theme.of(context).colorScheme.onSurfaceVariant);
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16),
      child: Row(
        children: [
          for (final c in columns)
            SizedBox(
              width: c.width * scale,
              child: Padding(
                padding: EdgeInsets.only(right: c.alignEnd ? 8 : 0),
                child: TermLabel(
                  c.title,
                  textAlign: c.alignEnd ? TextAlign.end : TextAlign.start,
                  alignment: c.alignEnd
                      ? MainAxisAlignment.end
                      : MainAxisAlignment.start,
                  style: style,
                ),
              ),
            ),
        ],
      ),
    );
  }
}