ynab_lite/lib/screens/budget_screen.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../providers/db_provider.dart';
import '../theme/app_theme.dart';
import 'package:drift/drift.dart' show Value;
import '../data/db.dart';

class BudgetScreen extends ConsumerWidget {
  const BudgetScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final groups = ref.watch(categoryGroupsProvider).valueOrNull ?? [];
    final catsByGroup = ref.watch(categoriesByGroupProvider);
    final now = DateTime.now();
    final months = ['', 'Janvier', 'Février', 'Mars', 'Avril', 'Mai', 'Juin', 'Juillet', 'Août', 'Septembre', 'Octobre', 'Novembre', 'Décembre'];
    final monthLabel = '${months[now.month]} ${now.year}';

    return ListView(
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 90),
      children: [
        Card(
          child: Padding(
            padding: const EdgeInsets.all(20),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text('Budget du mois', style: Theme.of(context).textTheme.titleMedium),
                const SizedBox(height: 4),
                Text(monthLabel, style: Theme.of(context).textTheme.bodySmall),
              ],
            ),
          ),
        ),
        const SizedBox(height: 16),
        ...groups.map((group) {
          final cats = catsByGroup[group.id] ?? [];
          if (cats.isEmpty) return const SizedBox.shrink();
          return _CategoryGroupTile(group: group, categoryIds: cats.map((c) => c.id).toList());
        }),
      ],
    );
  }
}

class _CategoryGroupTile extends ConsumerWidget {
  final CategoryGroup group;
  final List<int> categoryIds;

  const _CategoryGroupTile({required this.group, required this.categoryIds});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final expanded = ref.watch(_expandedGroupProvider(group.id));
    final cats = ref.watch(categoriesByGroupProvider)[group.id] ?? [];

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        InkWell(
          onTap: () => ref.read(_expandedGroupProvider(group.id).notifier).toggle(),
          borderRadius: BorderRadius.circular(8),
          child: Padding(
            padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 4),
            child: Row(
              children: [
                Icon(
                  expanded ? Icons.keyboard_arrow_down : Icons.keyboard_arrow_right,
                  size: 18,
                  color: Theme.of(context).colorScheme.onSurfaceVariant,
                ),
                const SizedBox(width: 8),
                Text(group.name,
                    style: Theme.of(context)
                        .textTheme
                        .titleSmall
                        ?.copyWith(fontWeight: FontWeight.w600)),
                const Spacer(),
                Text(
                  formatCurrency(
                    cats.fold(0.0, (s, c) => s + ref.watch(categoryRemainingProvider(c.id))),
                  ),
                  style: Theme.of(context).textTheme.bodySmall,
                ),
              ],
            ),
          ),
        ),
        if (expanded)
          ...cats.map((c) => _CategoryRow(categoryId: c.id)),
        const Divider(height: 1),
      ],
    );
  }
}

class _CategoryRow extends ConsumerWidget {
  final int categoryId;

  const _CategoryRow({required this.categoryId});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final cats = ref.watch(categoriesByGroupProvider);
    final category = cats.values
        .expand((list) => list)
        .firstWhere((c) => c.id == categoryId, orElse: () => throw StateError('missing'));

    final budgeted = ref.watch(monthlyBudgetProvider(categoryId)) ?? 0.0;
    final spent = ref.watch(categorySpentProvider(categoryId));
    final remaining = ref.watch(categoryRemainingProvider(categoryId));
    final pct = budgeted > 0 ? ((budgeted + spent) / budgeted).clamp(0.0, 1.0) : 0.0;

    void _editBudget() async {
      final month = ref.read(currentMonthProvider);
      final db = ref.read(dbProvider);
      final ctrl = TextEditingController(text: budgeted > 0 ? budgeted.toStringAsFixed(2) : '');

      final newAmount = await showDialog<double>(
        context: context,
        builder: (ctx) => AlertDialog(
          title: Text('Budget : ${category.name}'),
          content: TextField(
            controller: ctrl,
            decoration: const InputDecoration(labelText: 'Montant', hintText: '0,00'),
            keyboardType: const TextInputType.numberWithOptions(decimal: true),
            autofocus: true,
          ),
          actions: [
            TextButton(onPressed: () => Navigator.pop(ctx), child: const Text('Annuler')),
            FilledButton(
              onPressed: () {
                final v = double.tryParse(ctrl.text.trim().replaceAll(',', '.'));
                if (v != null) Navigator.pop(ctx, v);
              },
              child: const Text('Enregistrer'),
            ),
          ],
        ),
      );
      ctrl.dispose();

      if (newAmount == null) return;
      final existing = await (db.select(db.budgets)
        ..where((b) => b.categoryId.equals(categoryId))
        ..where((b) => b.month.equals(month)))
        .get();
      if (existing.isNotEmpty) {
        await db.update(db.budgets).replace(existing.first.copyWith(budgeted: newAmount));
      } else {
        await db.into(db.budgets).insert(BudgetsCompanion.insert(
          categoryId: categoryId,
          month: month,
          budgeted: Value(newAmount),
        ));
      }
    }

    return Padding(
      padding: const EdgeInsets.only(left: 8, bottom: 4),
      child: Card(
        margin: EdgeInsets.zero,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Expanded(
                    child: Text(category.name, style: Theme.of(context).textTheme.bodyMedium),
                  ),
                  Text(
                    formatCurrency(remaining),
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                          fontWeight: FontWeight.w600,
                          color: remaining >= 0 ? Theme.of(context).colorScheme.primary : Theme.of(context).colorScheme.error,
                        ),
                  ),
                ],
              ),
              const SizedBox(height: 4),
              ClipRRect(
                borderRadius: BorderRadius.circular(4),
                child: LinearProgressIndicator(
                  value: pct,
                  backgroundColor: Theme.of(context).colorScheme.outlineVariant,
                  valueColor: AlwaysStoppedAnimation<Color>(
                    remaining >= 0 ? Theme.of(context).colorScheme.primary : Theme.of(context).colorScheme.error,
                  ),
                  minHeight: 4,
                ),
              ),
              const SizedBox(height: 2),
              Row(
                children: [
                  GestureDetector(
                    onTap: _editBudget,
                    child: Text('Budget: ${formatCurrency(budgeted)}',
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                              decoration: TextDecoration.underline,
                              color: Theme.of(context).colorScheme.primary,
                            )),
                  ),
                  const SizedBox(width: 12),
                  Text('Dépensé: ${formatCurrency(spent.abs())}',
                      style: Theme.of(context).textTheme.bodySmall),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _ExpandedGroupNotifier extends StateNotifier<bool> {
  _ExpandedGroupNotifier() : super(true);

  void toggle() => state = !state;
}

final _expandedGroupProvider =
    StateNotifierProvider.family<_ExpandedGroupNotifier, bool, int>(
        (ref, id) => _ExpandedGroupNotifier());