import 'package:flutter/cupertino.dart';
import 'package:please_pay_me/core/format/formatters.dart';
import 'package:please_pay_me/data/models/budget.dart';
import 'package:please_pay_me/features/budgets/budget_form_sheet.dart';
import 'package:please_pay_me/features/budgets/budgets_controller.dart';
import 'package:please_pay_me/features/journal/journal_controller.dart';
import 'package:please_pay_me/theme/theme.dart';
import 'package:please_pay_me/ui/ui.dart';
import 'package:provider/provider.dart';

/// All envelopes: pick the active one, edit, archive or delete.
class BudgetsScreen extends StatelessWidget {
  const BudgetsScreen({super.key});

  @override
  Widget build(BuildContext context) {
    final controller = context.watch<BudgetsController>();

    return CupertinoPageScaffold(
      backgroundColor: AppColors.of(context, AppColors.groupedBackground),
      child: CustomScrollView(
        physics: const BouncingScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
        slivers: [
          AppLargeNavBar(
            title: 'Бюджеты',
            trailing: CupertinoButton(
              padding: EdgeInsets.zero,
              minimumSize: Size.zero,
              onPressed: () => showBudgetFormSheet(context: context, controller: controller),
              child: const AppIcon(CupertinoIcons.add_circled, color: AppColors.accent),
            ),
          ),
          CupertinoSliverRefreshControl(onRefresh: () => controller.load(silent: true)),
          SliverToBoxAdapter(
            child: controller.state.map(
              loading: () => AppListSection(
                children: List.generate(3, (_) => const AppSkeletonRow()),
              ),
              error: (message) => AppErrorView(message: message, onRetry: controller.load),
              data: (items) => items.isEmpty
                  ? AppEmptyState(
                      icon: CupertinoIcons.money_rubl_circle,
                      title: 'Бюджетов нет',
                      message: 'Создайте первый конверт до следующей зарплаты.',
                      actionLabel: 'Создать бюджет',
                      onAction: () =>
                          showBudgetFormSheet(context: context, controller: controller),
                    )
                  : _BudgetsList(items: items, controller: controller),
            ),
          ),
          const SliverToBoxAdapter(child: SizedBox(height: AppSpacing.s7)),
        ],
      ),
    );
  }
}

class _BudgetsList extends StatelessWidget {
  const _BudgetsList({required this.items, required this.controller});

  final List<BudgetStatus> items;
  final BudgetsController controller;

  @override
  Widget build(BuildContext context) {
    final active = items.where((status) => !status.isExpired).toList();
    final archived = items.where((status) => status.isExpired).toList();

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        if (active.isNotEmpty)
          AppListSection(
            header: 'Активные',
            footer: 'Нажмите, чтобы сделать бюджет текущим.',
            separatorIndent: 60,
            children: [
              for (final status in active)
                _BudgetRow(status: status, controller: controller),
            ],
          ),
        if (archived.isNotEmpty) ...[
          const SizedBox(height: AppSpacing.s5),
          AppListSection(
            header: 'Завершённые',
            separatorIndent: 60,
            children: [
              for (final status in archived)
                _BudgetRow(status: status, controller: controller),
            ],
          ),
        ],
      ],
    );
  }
}

class _BudgetRow extends StatelessWidget {
  const _BudgetRow({required this.status, required this.controller});

  final BudgetStatus status;
  final BudgetsController controller;

  @override
  Widget build(BuildContext context) {
    final currency = status.budget.currency;
    final subtitle = status.isExpired
        ? 'Завершён ${formatShortDate(status.budget.endDate)}'
        : '${formatDaysLeft(status.daysLeft)} · лимит ${formatMoney(status.dailyLimit, currency: currency)}';

    return AppListTile(
      leading: AppIconBadge(
        icon: status.selected ? CupertinoIcons.checkmark_alt : CupertinoIcons.tray_full,
        color: status.selected
            ? AppColors.accent
            : status.isExpired
                ? AppColors.systemGray
                : AppColors.systemOrange,
      ),
      title: status.budget.name,
      subtitle: subtitle,
      value: formatMoney(status.remaining, currency: currency),
      onTap: () => _openActions(context),
    );
  }

  Future<void> _openActions(BuildContext context) async {
    final journal = context.read<JournalController>();
    final index = await showAppActionSheet(
      context: context,
      title: status.budget.name,
      message: 'Остаток ${formatMoney(status.remaining, currency: status.budget.currency)}',
      actions: [
        if (!status.selected) const AppActionSheetAction(label: 'Сделать текущим', isDefault: true),
        const AppActionSheetAction(label: 'Редактировать'),
        AppActionSheetAction(label: status.budget.isActive ? 'В архив' : 'Вернуть из архива'),
        const AppActionSheetAction(label: 'Удалить', destructive: true),
      ],
    );

    if (index == null || !context.mounted) return;

    final actions = <String>[
      if (!status.selected) 'select',
      'edit',
      'archive',
      'delete',
    ];

    switch (actions[index]) {
      case 'select':
        final error = await controller.select(status.budget.id);
        journal.bindBudget(controller.selected?.budget.id);
        await journal.load(silent: true);
        if (context.mounted) {
          await showAppToast(context, message: error ?? 'Бюджет выбран');
        }
      case 'edit':
        await showBudgetFormSheet(
          context: context,
          controller: controller,
          initial: status,
        );
      case 'archive':
        final error = await controller.setActive(
          status.budget.id,
          isActive: !status.budget.isActive,
        );
        if (context.mounted) {
          await showAppToast(
            context,
            message: error ?? (status.budget.isActive ? 'Бюджет в архиве' : 'Бюджет активен'),
          );
        }
      case 'delete':
        await _confirmDelete(context, journal);
    }
  }

  Future<void> _confirmDelete(BuildContext context, JournalController journal) async {
    final confirmed = await showAppAlert(
      context: context,
      title: 'Удалить «${status.budget.name}»?',
      message: 'Вместе с бюджетом удалятся все его операции.',
      confirmLabel: 'Удалить',
      cancelLabel: 'Отмена',
      destructive: true,
    );

    if (confirmed != true) return;

    final error = await controller.delete(status.budget.id);
    journal.bindBudget(controller.selected?.budget.id);
    await journal.load(silent: true);

    if (context.mounted) {
      await showAppToast(context, message: error ?? 'Бюджет удалён');
    }
  }
}