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/budgets_controller.dart';
import 'package:please_pay_me/theme/theme.dart';
import 'package:please_pay_me/ui/ui.dart';

/// Create / edit form for an envelope.
class BudgetFormSheet extends StatefulWidget {
  const BudgetFormSheet({super.key, required this.onSubmit, this.initial});

  final BudgetStatus? initial;

  final Future<String?> Function({
    required String name,
    required double totalAmount,
    required DateTime startDate,
    required DateTime endDate,
    required bool resetExpenses,
  }) onSubmit;

  @override
  State<BudgetFormSheet> createState() => _BudgetFormSheetState();
}

class _BudgetFormSheetState extends State<BudgetFormSheet> {
  late final _nameController = TextEditingController(
    text: widget.initial?.budget.name ?? '',
  );
  late final _amountController = TextEditingController(
    text: widget.initial == null
        ? ''
        : widget.initial!.budget.totalAmount.toStringAsFixed(0),
  );

  late DateTime _startDate = widget.initial?.budget.startDate ?? DateTime.now();
  late DateTime _endDate =
      widget.initial?.budget.endDate ?? DateTime.now().add(const Duration(days: 14));

  bool _resetExpenses = false;
  bool _saving = false;
  String? _error;

  bool get _isEditing => widget.initial != null;

  @override
  void dispose() {
    _nameController.dispose();
    _amountController.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    final name = _nameController.text.trim();
    final amount = double.tryParse(
      _amountController.text.trim().replaceAll(',', '.').replaceAll(' ', ''),
    );

    if (name.isEmpty) {
      setState(() => _error = 'Введите название бюджета');
      return;
    }
    if (amount == null || amount <= 0) {
      setState(() => _error = 'Введите сумму больше нуля');
      return;
    }
    if (!_endDate.isAfter(_startDate)) {
      setState(() => _error = 'Дата окончания должна быть позже начала');
      return;
    }

    setState(() {
      _saving = true;
      _error = null;
    });

    final error = await widget.onSubmit(
      name: name,
      totalAmount: amount,
      startDate: _startDate,
      endDate: _endDate,
      resetExpenses: _resetExpenses,
    );

    if (!mounted) return;

    if (error != null) {
      setState(() {
        _saving = false;
        _error = error;
      });
      return;
    }

    Navigator.of(context).pop(true);
  }

  @override
  Widget build(BuildContext context) {
    return CupertinoPageScaffold(
      backgroundColor: AppColors.of(context, AppColors.groupedBackground),
      navigationBar: AppNavBar(
        title: _isEditing ? 'Бюджет' : 'Новый бюджет',
        leading: CupertinoButton(
          padding: EdgeInsets.zero,
          minimumSize: Size.zero,
          onPressed: _saving ? null : () => Navigator.of(context).pop(false),
          child: const AppText.body('Отмена', color: AppColors.accent),
        ),
      ),
      child: SafeArea(
        child: ListView(
          padding: const EdgeInsets.only(top: AppSpacing.s4, bottom: AppSpacing.s6),
          children: [
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: AppSpacing.gutter),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  AppTextField(
                    label: 'Название',
                    placeholder: 'До аванса',
                    controller: _nameController,
                    enabled: !_saving,
                  ),
                  const SizedBox(height: AppSpacing.s4),
                  AppTextField(
                    label: 'Сумма на период',
                    placeholder: '0',
                    controller: _amountController,
                    enabled: !_saving,
                    keyboardType: const TextInputType.numberWithOptions(decimal: true),
                  ),
                ],
              ),
            ),
            const SizedBox(height: AppSpacing.s5),
            AppListSection(
              header: 'Период',
              footer: 'Дневной лимит = остаток ÷ количество оставшихся дней.',
              children: [
                AppListTile(
                  title: 'Начало',
                  value: formatShortDate(_startDate),
                  onTap: _saving ? null : () => _pickDate(isStart: true),
                ),
                AppListTile(
                  title: 'Окончание',
                  value: formatShortDate(_endDate),
                  onTap: _saving ? null : () => _pickDate(isStart: false),
                ),
              ],
            ),
            if (_isEditing) ...[
              const SizedBox(height: AppSpacing.s5),
              AppListSection(
                footer: 'Сбросить траты — обнулить потраченное по этому бюджету.',
                children: [
                  AppSwitchRow(
                    title: 'Сбросить траты',
                    value: _resetExpenses,
                    onChanged: _saving ? null : (v) => setState(() => _resetExpenses = v),
                  ),
                ],
              ),
            ],
            if (_error != null)
              Padding(
                padding: const EdgeInsets.fromLTRB(
                  AppSpacing.gutter,
                  AppSpacing.s3,
                  AppSpacing.gutter,
                  0,
                ),
                child: AppText.footnote(_error!, color: AppColors.systemRed),
              ),
            const SizedBox(height: AppSpacing.s5),
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: AppSpacing.gutter),
              child: AppButton(
                label: _isEditing ? 'Сохранить' : 'Создать бюджет',
                loading: _saving,
                onPressed: _submit,
              ),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _pickDate({required bool isStart}) async {
    final picked = await showAppDatePicker(
      context: context,
      initialDate: isStart ? _startDate : _endDate,
      minimumDate: isStart ? null : _startDate,
    );
    if (picked == null || !mounted) return;

    setState(() {
      if (isStart) {
        _startDate = picked;
        if (!_endDate.isAfter(_startDate)) {
          _endDate = _startDate.add(const Duration(days: 14));
        }
      } else {
        _endDate = picked;
      }
    });
  }
}

/// Opens the sheet wired to [BudgetsController].
Future<void> showBudgetFormSheet({
  required BuildContext context,
  required BudgetsController controller,
  BudgetStatus? initial,
}) async {
  final saved = await showAppFormSheet<bool>(
    context: context,
    builder: (_) => BudgetFormSheet(
      initial: initial,
      onSubmit: ({
        required name,
        required totalAmount,
        required startDate,
        required endDate,
        required resetExpenses,
      }) {
        if (initial == null) {
          return controller.create(
            name: name,
            totalAmount: totalAmount,
            endDate: endDate,
            startDate: startDate,
          );
        }
        return controller.update(
          budgetId: initial.budget.id,
          name: name,
          totalAmount: totalAmount,
          endDate: endDate,
          startDate: startDate,
          resetExpenses: resetExpenses,
        );
      },
    ),
  );

  if (saved == true && context.mounted) {
    await showAppToast(
      context,
      message: initial == null ? 'Бюджет создан' : 'Бюджет обновлён',
    );
  }
}