Sample code for Orders

order_cafe.dart

class Topping {
  String name;
  double price;

  Topping(this.name, this.price);
}

class CafeItem {
  String name;
  int quantity;
  double price;
  List<Topping> toppings;

  CafeItem(this.name, this.price, this.toppings, {this.quantity = 1});

  double get total =>
      price * quantity +
      toppings.fold(0, (total, topping) => total + topping.price);
}

class Tax {
  double rate;

  Tax(this.rate);

  double apply(double amount) => amount * rate;
}

class Order {
  List<CafeItem> items;
  Tax tax;

  Order(this.items, this.tax);

  double get total => items.fold(0, (total, item) => total + item.total);
  double get taxAmount => tax.apply(total);

  void printReceipt() {
    print('Receipt:');
    for (var item in items) {
      print('  ${item.name} x${item.quantity} - \$${item.total}');
      for (var topping in item.toppings) {
        print('    ${topping.name} - \$${topping.price}');
      }
    }
    print('Subtotal: \$$total');
    print('Tax: \$$taxAmount');
    print('Total: \$${total + taxAmount}');
  }
}

void main() {
  var order = Order([
    CafeItem(
        'Coffee',
        2.5,
        [
          Topping('Milk', 0.5),
          Topping('Ice Level 70%', 0),
          Topping('Sugar 50%', 0)
        ],
        quantity: 2),
    CafeItem('Iced Latte', 3.5, [
      Topping('Milk', 0.5),
      Topping('Ice Cream', 1.0),
      Topping('Sugar 100%', 0),
      Topping('Whipped Cream', 0.5)
    ]),
    CafeItem('Sandwich', 4.5, [Topping('Cheese', 1.0), Topping('Ham', 1.5)]),
    CafeItem('Salad', 5.5, [Topping('Olives', 0.5), Topping('Artichokes', 1.0)],
        quantity: 3),
  ], Tax(0.1));

  order.printReceipt();
}

order_cafe_with_promotion.dart

class Topping {
  String name;
  double price;

  Topping(this.name, this.price);
}

class CafeItem {
  String name;
  int quantity;
  double price;
  List<Topping> toppings;

  CafeItem(this.name, this.price, this.toppings, {this.quantity = 1});

  double get total =>
      price * quantity +
      toppings.fold(0, (total, topping) => total + topping.price);
}

class Tax {
  double rate;

  Tax(this.rate);

  double apply(double amount) => amount * rate;

  @override
  String toString() {
    return 'Tax Rate: ${(rate * 100).toStringAsFixed(0)}%';
  }
}

class Promotion {
  final String name;
  final DateTime startDate;
  final DateTime expiryDate;
  final String schedule;
  final String conditionType;
  final List<String> conditionValues;
  final String discountType;
  final double discountValue;

  Promotion({
    required this.name,
    required this.startDate,
    required this.expiryDate,
    required this.schedule,
    required this.conditionType,
    required this.conditionValues,
    required this.discountType,
    required this.discountValue,
  });

  bool isApplicable(DateTime date) {
    if (date.isBefore(startDate) || date.isAfter(expiryDate)) {
      return false;
    }
    if (schedule.toLowerCase() == 'every friday' &&
        date.weekday != DateTime.friday) {
      return false;
    }
    return true;
  }

  double applyDiscount(double originalPrice, String category) {
    if (conditionValues.contains(category)) {
      if (discountType.toLowerCase() == 'percentage') {
        return originalPrice * (1 - discountValue / 100);
      } else if (discountType.toLowerCase() == 'fixed amount') {
        return originalPrice - discountValue;
      } else if (discountType.toLowerCase() == 'free') {
        return 0.0;
      }
    }
    return originalPrice;
  }
}

class Order {
  List<CafeItem> items;
  Tax tax;
  Promotion? promotion;

  Order(this.items, this.tax, {this.promotion});

  double get total {
    double total = 0;
    DateTime now = DateTime.now();
    for (var item in items) {
      double itemTotal = item.total;
      if (promotion != null && promotion!.isApplicable(now)) {
        itemTotal = promotion!.applyDiscount(itemTotal, item.name);
      }
      total += itemTotal;
    }
    return total;
  }

  double get promotionDiscount {
    double discount = 0;
    DateTime now = DateTime.now();
    for (var item in items) {
      double itemTotal = item.total;
      if (promotion != null && promotion!.isApplicable(now)) {
        discount += itemTotal - promotion!.applyDiscount(itemTotal, item.name);
      }
    }
    return discount;
  }

  double get taxAmount => tax.apply(total);
  double get totalAmount => total + taxAmount;

  void printReceipt() {
    print('Receipt:');
    for (var item in items) {
      double itemTotal = item.total;
      if (promotion != null && promotion!.isApplicable(DateTime.now())) {
        itemTotal = promotion!.applyDiscount(itemTotal, item.name);
      }
      print(
          '  ${item.name} x${item.quantity} - \$${itemTotal.toStringAsFixed(2)}');
      for (var topping in item.toppings) {
        print('    ${topping.name} - \$${topping.price}');
      }
    }

    String subtotal = (total + promotionDiscount).toStringAsFixed(2);
    print('---');
    print('Subtotal: \$$subtotal');
    print('Promotion: ${promotion != null ? promotion!.name : 'None'}');
    print('Discount: \$${promotionDiscount.toStringAsFixed(2)}');
    print('Total: \$$total');
    print('Tax: \$$taxAmount ($tax)');
    print('Grand Total: \$${(totalAmount).toStringAsFixed(2)}');
  }
}

void main() {
  Promotion blackFridaySale = Promotion(
    name: 'Black Friday Sale',
    startDate: DateTime.parse('2024-06-05 08:00:00'),
    expiryDate: DateTime.parse('2024-07-10 17:00:00'),
    schedule: 'Every Friday',
    conditionType: 'Category',
    conditionValues: ['Coffee', 'Iced Latte', 'Sandwich', 'Salad'],
    discountType: 'Percentage',
    discountValue: 10.0,
  );

  var order = Order([
    CafeItem(
        'Coffee',
        2.5,
        [
          Topping('Milk', 0.5),
          Topping('Ice Level 70%', 0),
          Topping('Sugar 50%', 0)
        ],
        quantity: 2),
    CafeItem('Iced Latte', 3.5, [
      Topping('Milk', 0.5),
      Topping('Ice Cream', 1.0),
      Topping('Sugar 100%', 0),
      Topping('Whipped Cream', 0.5)
    ]),
    CafeItem('Sandwich', 4.5, [Topping('Cheese', 1.0), Topping('Ham', 1.5)]),
    CafeItem('Salad', 5.5, [Topping('Olives', 0.5), Topping('Artichokes', 1.0)],
        quantity: 3),
  ], Tax(0.1), promotion: blackFridaySale);

  order.printReceipt();
}

order_pizza.dart

class Topping {
  String name;
  double price;

  Topping(this.name, this.price);
}

class Pizza {
  String name;
  double price;
  List<Topping> toppings;

  Pizza(this.name, this.price, this.toppings);

  double get total => price + toppings.fold(0, (total, topping) => total + topping.price);
}

class Order {
  List<Pizza> pizzas;

  Order(this.pizzas);

  double get total => pizzas.fold(0, (total, pizza) => total + pizza.total);

  void printReceipt() {
    print('Receipt:');
    for (var pizza in pizzas) {
      print('  ${pizza.name} - \$${pizza.total}');
      for (var topping in pizza.toppings) {
        print('    ${topping.name} - \$${topping.price}');
      }
    }
    print('Total: \$$total');
  }
}

void main() {
  var order = Order([
    Pizza('Margherita', 5.5, []),
    Pizza('Capricciosa', 7.5, [Topping('Mushrooms', 1.0), Topping('Ham', 1.5)]),
    Pizza('Quattro Stagioni', 8.5, [Topping('Mushrooms', 1.0), Topping('Ham', 1.5), Topping('Olives', 0.5), Topping('Artichokes', 1.0)]),
  ]);

  order.printReceipt();
}