import 'package:flutter_test/flutter_test.dart';
import 'package:kooltab2/models/tab_item.dart';
import 'package:kooltab2/services/bar_tab_service.dart';
import 'package:kooltab2/services/product_service.dart';
import 'package:kooltab2/viewmodels/bar_screen_view_model.dart';
import 'package:kooltab2/viewmodels/inventory_view_model.dart';
import 'package:mocktail/mocktail.dart';

class MockBarTabService extends Mock implements BarTabService {}

class MockProductService extends Mock implements ProductService {}

void main() {
  late MockBarTabService barTabService;
  late MockProductService productService;
  late InventoryViewModel inventory;
  late BarScreenViewModel viewModel;

  setUp(() {
    barTabService = MockBarTabService();
    productService = MockProductService();
    inventory = InventoryViewModel(productService: productService);
    viewModel = BarScreenViewModel(
      barTabService: barTabService,
      inventory: inventory,
    );
  });

  test('propagates an insufficient-stock error from the transaction', () async {
    const item = TabItem(
      id: 'item-1',
      tabId: 'tab-1',
      productId: 'prod-1',
      productName: 'Chips',
      quantity: 20,
      unitPriceInCents: 150,
    );

    when(
      () => barTabService.adjustTabItemQuantity(tabItemId: 'item-1', delta: 1),
    ).thenAnswer((_) async => throw const InsufficientStockException());

    await expectLater(
      viewModel.changeItemQuantity(item, 1),
      throwsA(isA<InsufficientStockException>()),
    );

    expect(viewModel.errorMessage, isNull);
    verify(
      () => barTabService.adjustTabItemQuantity(tabItemId: 'item-1', delta: 1),
    ).called(1);
  });
}