// Classes +
// Methods +
// Enums +
// Loops +
// Generics (можно использовать List<>) +-
// Anonymous functions +
// Future +
// extension +

enum Category { PHONE, COMPUTER, TV }

extension ProductX on Product {
  double get discountedPrice => price * 0.9; // Применяем 10% скидку
  String get fullname => '${name} (${category.name}) - \$${price}';
}

class Product {
  String name;
  double price;
  int quantity;
  Category category;

  // Constructor
  Product(this.name, this.price, this.quantity, this.category);
}

class Cart {
  final List<Product> items = [];

  void push(Product p) {
    items.add(p);
  }

  double getTotalPrice() {
    double price = 0;
    for (int i = 0; i < items.length; i++) {
      price += items[i].quantity * items[i].price;
    }

    return price;
  }

  int getItemsCount() {
    return items.fold(0, (total, item) => total + item.quantity);
  }

  Future<List<Product>> getItemsAsync() async {
    // Как бы делаем запрос к бэку
    await Future.delayed(Duration(seconds: 3));
    return items;
  }
}

void main() {
  Cart cart = Cart();
  Product product = Product('Laptop', 1000.0, 1, Category.COMPUTER);
  cart.push(product);
  cart.push(Product('Smartphone', 500.0, 2, Category.PHONE));
  cart.push(Product('TV', 800.0, 1, Category.TV));

  print('Total price: \$${cart.getTotalPrice()}');
  print('Total items count: ${cart.getItemsCount()}');

  print('Product with discount: ${product.discountedPrice}');
  print('Product fullname: ${product.fullname}');

  Future.delayed(Duration(seconds: 3)).then((_) => print(product.name));

//   List<Product> products = await cart.getItemsAsync();
//   print('Number of elements received from async method: ${products.length}');
}