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

import '../../core/utils/ru_date.dart';
import '../../core/widgets/async_value_view.dart';
import '../../core/widgets/money_text.dart';
import '../portfolio/labels.dart' show formatPercent;
import 'data/goals_api.dart';
import 'providers.dart';

/// What the projection is built on. `none` is not an error — it means there is no trend to
/// extrapolate yet, which is different from "the goal is not reachable".
const goalBasisLabels = {
  'xirr': 'по доходности',
  'contribution': 'по взносам',
  'none': 'нет данных',
};

const goalBasisDescriptions = {
  'xirr': 'Прогноз построен на фактической доходности портфеля (XIRR).',
  'contribution': 'Прогноз построен на регулярных взносах, без учёта доходности.',
  'none': 'Данных для прогноза нет: ни доходности, ни истории взносов.',
};

String goalBasisLabel(String basis) => goalBasisLabels[basis] ?? basis;

/// One goal with its server-computed progress.
///
/// The load-bearing line is the projected date: `projected_date == null` means **the goal
/// is not reached at the current trend**, and it is written out in those words. Leaving the
/// spot blank, or filling it with a far-off date, would both read as an answer.
class GoalCard extends ConsumerWidget {
  const GoalCard({required this.goal, super.key, this.onEdit, this.onDelete});

  final Goal goal;
  final VoidCallback? onEdit;
  final VoidCallback? onDelete;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final progress = ref.watch(goalProgressProvider(goal.id));
    final theme = Theme.of(context);

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(goal.name, style: theme.textTheme.titleMedium),
                      Text(
                        [
                          'цель ${MoneyText.format(goal.targetAmount, goal.currency)}',
                          if (goal.targetDate != null) 'к ${ruDate(goal.targetDate!)}',
                          if (goal.monthlyContribution != null)
                            'взнос ${MoneyText.format(goal.monthlyContribution!, goal.currency)}/мес',
                          if (goal.archived) 'в архиве',
                        ].join(' · '),
                        style: theme.textTheme.bodySmall?.copyWith(color: theme.hintColor),
                      ),
                    ],
                  ),
                ),
                if (onEdit != null)
                  IconButton(
                    tooltip: 'Изменить',
                    icon: const Icon(Icons.edit_outlined),
                    onPressed: onEdit,
                  ),
                if (onDelete != null)
                  IconButton(
                    tooltip: 'Удалить',
                    icon: const Icon(Icons.delete_outline),
                    onPressed: onDelete,
                  ),
              ],
            ),
            const SizedBox(height: 12),
            AsyncValueView(
              value: progress,
              onRetry: () => ref.invalidate(goalProgressProvider(goal.id)),
              data: (cached) => GoalProgressView(goal: goal, progress: cached.data),
            ),
          ],
        ),
      ),
    );
  }
}

/// The progress body, split out of [GoalCard] so it can be rendered (and tested) without a
/// provider container.
class GoalProgressView extends StatelessWidget {
  const GoalProgressView({required this.goal, required this.progress, super.key});

  final Goal goal;
  final GoalProgress progress;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final share = Decimal.tryParse(progress.progress ?? '') ?? Decimal.zero;
    final clamped = share.toDouble().clamp(0.0, 1.0);
    final unreachable = progress.projectedDate == null;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        ClipRRect(
          borderRadius: BorderRadius.circular(4),
          child: LinearProgressIndicator(value: clamped, minHeight: 8),
        ),
        const SizedBox(height: 6),
        Row(
          children: [
            Text(
              formatPercent(progress.progress, signed: false),
              style: theme.textTheme.titleSmall,
            ),
            const SizedBox(width: 8),
            Expanded(
              child: Text(
                '${progress.currentValueRub == null ? '—' : MoneyText.format(progress.currentValueRub!, 'RUB')}'
                ' из '
                '${progress.targetAmountRub == null ? '—' : MoneyText.format(progress.targetAmountRub!, 'RUB')}',
                style: theme.textTheme.bodySmall,
              ),
            ),
            Tooltip(
              message: goalBasisDescriptions[progress.basis] ?? progress.basis,
              child: Chip(
                label: Text('Основание: ${goalBasisLabel(progress.basis)}'),
                visualDensity: VisualDensity.compact,
              ),
            ),
          ],
        ),
        const SizedBox(height: 10),
        // The whole point of the screen. Null is a statement, not an absence.
        Row(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Icon(
              unreachable ? Icons.trending_flat : Icons.flag_outlined,
              size: 18,
              color: unreachable ? theme.colorScheme.error : theme.colorScheme.primary,
            ),
            const SizedBox(width: 8),
            Expanded(
              child: Text(
                unreachable
                    ? (progress.basis == 'none'
                        ? 'Прогноз недоступен: данных для оценки тренда пока нет'
                        : 'При текущем тренде цель не достигается')
                    : 'Прогнозная дата достижения: ${ruDate(progress.projectedDate!)}',
                style: theme.textTheme.bodyMedium?.copyWith(
                  color: unreachable ? theme.colorScheme.error : null,
                  fontWeight: FontWeight.w500,
                ),
              ),
            ),
          ],
        ),
        const SizedBox(height: 6),
        Wrap(
          spacing: 16,
          runSpacing: 4,
          children: [
            Text(
              progress.monthlyNeededRub == null
                  ? 'Нужный ежемесячный взнос: — (нет целевой даты)'
                  : 'Нужно докладывать: '
                      '${MoneyText.format(progress.monthlyNeededRub!, 'RUB')}/мес',
              style: theme.textTheme.bodySmall,
            ),
            if (progress.assumedRate != null)
              Text(
                'Заложенная доходность: ${formatPercent(progress.assumedRate, signed: false)}',
                style: theme.textTheme.bodySmall,
              ),
            Text(
              progress.onTrack ? 'Идёт по плану' : 'Отстаёт от плана',
              style: theme.textTheme.bodySmall?.copyWith(
                color: progress.onTrack ? null : theme.colorScheme.error,
              ),
            ),
            if (progress.asOf != null)
              Text('на ${ruDate(progress.asOf!)}', style: theme.textTheme.bodySmall),
          ],
        ),
      ],
    );
  }
}