import 'package:dio/dio.dart';
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 'package:go_router/go_router.dart';

import '../../core/auth/auth_controller.dart';
import '../../core/cache/cached.dart';
import '../../core/theme/chart_colors.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/stale_banner.dart';
import '../../core/api/api_client.dart';
import 'providers.dart';

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

Color _severityColor(String severity) {
  final s = severity.toLowerCase();
  if (s.contains('crit') || s.contains('err')) return const Color(0xFFD03B3B);
  if (s.contains('warn')) return const Color(0xFFFAB219);
  if (s.contains('info') || s.contains('low')) return const Color(0xFF0CA30C);
  return const Color(0xFFEC835A);
}

/// Обзор: the dashboard landing page — net worth, this month's cashflow,
/// runway, a net worth line chart, a 12-month income/expense bar chart, and
/// a data-quality summary linking to the findings.
class HomePage extends ConsumerStatefulWidget {
  const HomePage({super.key});

  @override
  ConsumerState<HomePage> createState() => _HomePageState();
}

class _HomePageState extends ConsumerState<HomePage> {
  bool _refreshing = false;

  Future<void> _refresh() async {
    setState(() => _refreshing = true);
    try {
      await ref.read(apiProvider).getMetricsApi().metricsRefresh();
    } on DioException catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(problemMessage(e))));
    } finally {
      if (mounted) setState(() => _refreshing = false);
      invalidateHomeProviders(ref);
    }
  }

  void _showDataQuality(List<DataQualityRow> rows) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (context) => SafeArea(
        child: Padding(
          padding: const EdgeInsets.all(20),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text('Качество данных', style: Theme.of(context).textTheme.titleLarge),
              const SizedBox(height: 12),
              if (rows.isEmpty) const Text('Проблем не найдено.'),
              for (final row in rows)
                Padding(
                  padding: const EdgeInsets.symmetric(vertical: 6),
                  child: Row(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Container(
                        margin: const EdgeInsets.only(top: 4, right: 8),
                        width: 10,
                        height: 10,
                        decoration:
                            BoxDecoration(color: _severityColor(row.severity), shape: BoxShape.circle),
                      ),
                      Expanded(
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            Text('${row.checkName} (${row.count})',
                                style: Theme.of(context).textTheme.titleSmall),
                            Text(row.detail),
                          ],
                        ),
                      ),
                    ],
                  ),
                ),
            ],
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final breakdown = ref.watch(netWorthBreakdownProvider);
    final series = ref.watch(netWorthSeriesProvider);
    final thisMonth = ref.watch(cashflowThisMonthProvider);
    final last12 = ref.watch(cashflowLast12Provider);
    final runway = ref.watch(runwayProvider);
    final status = ref.watch(metricsStatusProvider);
    final dataQuality = ref.watch(dataQualityProvider);
    final portfolio = ref.watch(portfolioSummaryHomeProvider);

    final stale = oldestFetch([
      breakdown.valueOrNull?.fetchedAt,
      series.valueOrNull?.fetchedAt,
      thisMonth.valueOrNull?.fetchedAt,
      last12.valueOrNull?.fetchedAt,
      runway.valueOrNull?.fetchedAt,
      status.valueOrNull?.fetchedAt,
      dataQuality.valueOrNull?.fetchedAt,
      portfolio.valueOrNull?.fetchedAt,
    ]);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Обзор'),
        actions: [
          IconButton(
            tooltip: 'Пересчитать метрики',
            icon: _refreshing
                ? const SizedBox(
                    width: 20, height: 20, child: CircularProgressIndicator(strokeWidth: 2))
                : const Icon(Icons.refresh),
            onPressed: _refreshing ? null : _refresh,
          ),
        ],
      ),
      body: RefreshIndicator(
        onRefresh: () async => invalidateHomeProviders(ref),
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            if (stale != null) StaleBanner(fetchedAt: stale),
            Row(
              children: [
                Expanded(
                  child: AsyncValueView(
                    value: status,
                    onRetry: () => ref.invalidate(metricsStatusProvider),
                    data: (cached) {
                      final log = cached.data;
                      final at = log?.finishedAt ?? log?.startedAt;
                      final text = at == null
                          ? 'Данные ещё не пересчитывались'
                          : 'Данные на ${ruDate(at.toLocal())} ${at.toLocal().hour.toString().padLeft(2, '0')}:${at.toLocal().minute.toString().padLeft(2, '0')}';
                      return Text(text, style: Theme.of(context).textTheme.bodySmall);
                    },
                  ),
                ),
                AsyncValueView(
                  value: dataQuality,
                  data: (cached) {
                    final rows = cached.data;
                    return ActionChip(
                      avatar: Icon(
                        rows.isEmpty ? Icons.check_circle_outline : Icons.warning_amber_outlined,
                        size: 18,
                        color: rows.isEmpty ? Colors.green : _severityColor(rows.first.severity),
                      ),
                      label: Text(rows.isEmpty ? 'ок' : '${rows.length} замечаний'),
                      onPressed: rows.isEmpty ? null : () => _showDataQuality(rows),
                    );
                  },
                ),
              ],
            ),
            const SizedBox(height: 16),
            AsyncValueView(
              value: breakdown,
              onRetry: () => ref.invalidate(netWorthBreakdownProvider),
              data: (cached) => _NetWorthTiles(breakdown: cached.data),
            ),
            const SizedBox(height: 12),
            Row(
              children: [
                Expanded(
                  child: AsyncValueView(
                    value: thisMonth,
                    onRetry: () => ref.invalidate(cashflowThisMonthProvider),
                    data: (cached) => _MonthTiles(month: cached.data),
                  ),
                ),
              ],
            ),
            const SizedBox(height: 12),
            AsyncValueView(
              value: portfolio,
              onRetry: () => ref.invalidate(portfolioSummaryHomeProvider),
              data: (cached) =>
                  cached.data == null ? const SizedBox.shrink() : _PortfolioTiles(summary: cached.data!),
            ),
            const SizedBox(height: 12),
            AsyncValueView(
              value: runway,
              onRetry: () => ref.invalidate(runwayProvider),
              data: (cached) => _RunwayTile(runway: cached.data),
            ),
            const SizedBox(height: 24),
            LayoutBuilder(
              builder: (context, constraints) {
                final wide = constraints.maxWidth >= 900;
                final netWorthChart = _ChartCard(
                  title: 'Капитал за 365 дней',
                  child: AsyncValueView(
                    value: series,
                    onRetry: () => ref.invalidate(netWorthSeriesProvider),
                    data: (cached) => cached.data.isEmpty
                        ? const EmptyState(icon: Icons.show_chart, message: 'Пока нет данных.')
                        : _NetWorthChart(rows: cached.data),
                  ),
                );
                final cashflowChart = _ChartCard(
                  title: 'Доход и расход, 12 месяцев',
                  child: AsyncValueView(
                    value: last12,
                    onRetry: () => ref.invalidate(cashflowLast12Provider),
                    data: (cached) => cached.data.isEmpty
                        ? const EmptyState(icon: Icons.bar_chart, message: 'Пока нет данных.')
                        : _IncomeExpenseChart(rows: cached.data),
                  ),
                );
                if (wide) {
                  return Row(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Expanded(child: netWorthChart),
                      const SizedBox(width: 16),
                      Expanded(child: cashflowChart),
                    ],
                  );
                }
                return Column(
                  children: [netWorthChart, const SizedBox(height: 16), cashflowChart],
                );
              },
            ),
            const SizedBox(height: 8),
            Align(
              alignment: Alignment.centerRight,
              child: TextButton.icon(
                onPressed: () => context.go('/sync'),
                icon: const Icon(Icons.sync, size: 16),
                label: const Text('Синхронизация'),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _StatTile extends StatelessWidget {
  const _StatTile({required this.label, required this.value});
  final String label;
  final Widget value;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 168,
      child: Card(
        child: Padding(
          padding: const EdgeInsets.all(12),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(label, style: Theme.of(context).textTheme.bodySmall),
              const SizedBox(height: 4),
              DefaultTextStyle(style: Theme.of(context).textTheme.titleMedium!, child: value),
            ],
          ),
        ),
      ),
    );
  }
}

class _NetWorthTiles extends StatelessWidget {
  const _NetWorthTiles({required this.breakdown});
  final NetWorthBreakdown breakdown;

  @override
  Widget build(BuildContext context) {
    return Wrap(
      spacing: 12,
      runSpacing: 12,
      children: [
        _StatTile(label: 'Капитал сегодня', value: MoneyText(breakdown.totalRub, currency: 'RUB')),
        _StatTile(label: 'Ликвидные', value: MoneyText(breakdown.liquidRub, currency: 'RUB')),
        _StatTile(label: 'Сбережения', value: MoneyText(breakdown.savingsRub, currency: 'RUB')),
        _StatTile(label: 'Инвестиции', value: MoneyText(breakdown.investmentRub, currency: 'RUB')),
        _StatTile(label: 'Долги', value: MoneyText(breakdown.debtRub, currency: 'RUB')),
      ],
    );
  }
}

class _MonthTiles extends StatelessWidget {
  const _MonthTiles({required this.month});
  final CashFlowMonth? month;

  @override
  Widget build(BuildContext context) {
    if (month == null) {
      return const EmptyState(icon: Icons.event_note_outlined, message: 'Данных за этот месяц нет.');
    }
    final rateText = month!.savingsRate == null ? '—' : '${(_d(month!.savingsRate!) * 100).toStringAsFixed(1)}%';
    return Wrap(
      spacing: 12,
      runSpacing: 12,
      children: [
        _StatTile(label: 'Доход в этом месяце', value: MoneyText(month!.incomeRub, currency: 'RUB')),
        _StatTile(label: 'Расход в этом месяце', value: MoneyText(month!.expenseRub, currency: 'RUB')),
        _StatTile(label: 'Норма сбережений', value: Text(rateText)),
      ],
    );
  }
}

class _RunwayTile extends StatelessWidget {
  const _RunwayTile({required this.runway});
  final RunwayOut runway;

  @override
  Widget build(BuildContext context) {
    final text = runway.runwayMonths == null
        ? '—'
        : '${_d(runway.runwayMonths!).toStringAsFixed(1)} мес.';
    return _StatTile(label: 'Запас хода (runway)', value: Text(text));
  }
}

class _ChartCard extends StatelessWidget {
  const _ChartCard({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.titleSmall),
            const SizedBox(height: 12),
            SizedBox(height: 200, child: child),
          ],
        ),
      ),
    );
  }
}

class _NetWorthChart extends StatelessWidget {
  const _NetWorthChart({required this.rows});
  final List<NetWorthDay> rows;

  @override
  Widget build(BuildContext context) {
    final spots = [
      for (var i = 0; i < rows.length; i++) FlSpot(i.toDouble(), _d(rows[i].totalRub)),
    ];
    return LineChart(
      LineChartData(
        gridData: const FlGridData(drawVerticalLine: false),
        borderData: FlBorderData(show: false),
        titlesData: const FlTitlesData(
          topTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
          rightTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
          bottomTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
          leftTitles: AxisTitles(sideTitles: SideTitles(showTitles: false)),
        ),
        lineTouchData: LineTouchData(
          touchTooltipData: LineTouchTooltipData(
            getTooltipItems: (spots) => [
              for (final s in spots)
                LineTooltipItem(
                  MoneyText.format(s.y.toStringAsFixed(2), 'RUB'),
                  const TextStyle(color: Colors.white, fontSize: 12),
                ),
            ],
          ),
        ),
        lineBarsData: [
          LineChartBarData(
            spots: spots,
            isCurved: false,
            barWidth: 2,
            color: ChartColors.slot1Blue,
            dotData: const FlDotData(show: false),
          ),
        ],
      ),
    );
  }
}

class _IncomeExpenseChart extends StatelessWidget {
  const _IncomeExpenseChart({required this.rows});
  final List<CashFlowMonth> rows;

  @override
  Widget build(BuildContext context) {
    final maxY = rows.fold<double>(
      0,
      (m, r) => [m, _d(r.incomeRub), _d(r.expenseRub)].reduce((a, b) => a > b ? a : b),
    );
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(
          children: const [
            _LegendDot(color: ChartColors.income, label: 'Доход'),
            SizedBox(width: 16),
            _LegendDot(color: ChartColors.expense, label: 'Расход'),
          ],
        ),
        const SizedBox(height: 8),
        Expanded(
          child: BarChart(
            BarChartData(
              maxY: maxY * 1.1,
              gridData: const FlGridData(drawVerticalLine: false),
              borderData: FlBorderData(show: false),
              titlesData: FlTitlesData(
                topTitles: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
                rightTitles: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
                leftTitles: const AxisTitles(sideTitles: SideTitles(showTitles: false)),
                bottomTitles: AxisTitles(
                  sideTitles: SideTitles(
                    showTitles: true,
                    getTitlesWidget: (value, meta) {
                      final i = value.toInt();
                      if (i < 0 || i >= rows.length) return const SizedBox.shrink();
                      return Padding(
                        padding: const EdgeInsets.only(top: 6),
                        child:
                            Text(ruMonthYearShort(rows[i].month), style: const TextStyle(fontSize: 9)),
                      );
                    },
                  ),
                ),
              ),
              barTouchData: BarTouchData(
                touchTooltipData: BarTouchTooltipData(
                  getTooltipItem: (group, groupIndex, rod, rodIndex) {
                    final label = rodIndex == 0 ? 'Доход' : 'Расход';
                    return BarTooltipItem(
                      '$label\n${MoneyText.format(rod.toY.toStringAsFixed(2), 'RUB')}',
                      const TextStyle(color: Colors.white, fontSize: 12),
                    );
                  },
                ),
              ),
              barGroups: [
                for (var i = 0; i < rows.length; i++)
                  BarChartGroupData(
                    x: i,
                    barRods: [
                      BarChartRodData(toY: _d(rows[i].incomeRub), color: ChartColors.income, width: 6),
                      BarChartRodData(toY: _d(rows[i].expenseRub), color: ChartColors.expense, width: 6),
                    ],
                    barsSpace: 2,
                  ),
              ],
            ),
          ),
        ),
      ],
    );
  }
}

class _LegendDot extends StatelessWidget {
  const _LegendDot({required this.color, required this.label});
  final Color color;
  final String label;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Container(width: 10, height: 10, decoration: BoxDecoration(color: color, shape: BoxShape.circle)),
        const SizedBox(width: 6),
        Text(label, style: Theme.of(context).textTheme.bodySmall),
      ],
    );
  }
}

/// The investment row of the dashboard: value, profit and the two returns, each linking
/// through to Портфель. Absent entirely until a broker ledger exists.
class _PortfolioTiles extends StatelessWidget {
  const _PortfolioTiles({required this.summary});

  final SummaryOut summary;

  @override
  Widget build(BuildContext context) {
    final yearly = summary.returns.where((r) => r.period == '1y').firstOrNull;
    return InkWell(
      onTap: () => context.go('/portfolio'),
      borderRadius: BorderRadius.circular(12),
      child: Wrap(
        spacing: 12,
        runSpacing: 12,
        children: [
          _StatTile(
            label: 'Портфель',
            value: MoneyText(summary.totalRub, currency: 'RUB'),
          ),
          _StatTile(
            label: 'Прибыль',
            value: summary.pnlTotalRub == null
                // null, not zero: something in the portfolio has no price today
                ? const Text('—')
                : MoneyText(summary.pnlTotalRub!, currency: 'RUB'),
          ),
          _StatTile(
            label: 'XIRR, год',
            value: Text(_percent(yearly?.xirr)),
          ),
          _StatTile(
            label: 'TWR, год',
            value: Text(_percent(yearly?.twr)),
          ),
        ],
      ),
    );
  }

  static String _percent(String? value) {
    if (value == null) return '—';
    final pct = _d(value) * 100;
    final sign = pct > 0 ? '+' : '';
    return '$sign${pct.toStringAsFixed(2).replaceAll('.', ',')} %';
  }
}