مشروع ختامي: نظام تجارة إلكترونية بالأنماط

interface PaymentStrategy {
  pay(amount: number): Promise<boolean>;
}

class CreditCardPayment implements PaymentStrategy {
  async pay(amount: number) {
    console.log(`دفع ${amount} ببطاقة ائتمان`);
    return true;
  }
}

class PayPalPayment implements PaymentStrategy {
  async pay(amount: number) {
    console.log(`دفع ${amount} عبر PayPal`);
    return true;
  }
}

class COD_Payment implements PaymentStrategy {
  async pay(amount: number) {
    console.log(`الدفع عند الاستلام: ${amount}`);
    return true;
  }
}

interface Observer {
  update(event: string, data: any): void;
}

class EmailNotifier implements Observer {
  update(event: string, data: any) {
    if (event === "order:created") {
      console.log(`إرسال إيميل: تم إنشاء الطلب ${data.orderId}`);
    }
  }
}

class SMSNotifier implements Observer {
  update(event: string, data: any) {
    console.log(`إرسال SMS: الطلب ${data.orderId} في الطريق`);
  }
}

class OrderSubject {
  private observers: Observer[] = [];

  attach(observer: Observer) {
    this.observers.push(observer);
  }

  notify(event: string, data: any) {
    this.observers.forEach((obs) => obs.update(event, data));
  }
}

interface Product {
  id: string;
  name: string;
  price: number;
  getDetails(): string;
}

class PhysicalProduct implements Product {
  constructor(
    public id: string,
    public name: string,
    public price: number,
    public weight: number,
  ) {}

  getDetails() {
    return `${this.name} - ${this.price} ريال - وزن ${this.weight}kg`;
  }
}

class DigitalProduct implements Product {
  constructor(
    public id: string,
    public name: string,
    public price: number,
    public downloadLink: string,
  ) {}

  getDetails() {
    return `${this.name} - ${this.price} ريال - تحميل فوري`;
  }
}

class ProductFactory {
  static create(type: "physical" | "digital", data: any): Product {
    switch (type) {
      case "physical":
        return new PhysicalProduct(data.id, data.name, data.price, data.weight);
      case "digital":
        return new DigitalProduct(data.id, data.name, data.price, data.link);
    }
  }
}

abstract class OrderDecorator implements Product {
  constructor(protected product: Product) {}

  abstract getDetails(): string;
}

class GiftWrapping extends OrderDecorator {
  getDetails() {
    return `${this.product.getDetails()} + تغليف هدية (15 ريال)`;
  }

  get price() {
    return (this.product as any).price + 15;
  }
}

class ExpressShipping extends OrderDecorator {
  getDetails() {
    return `${this.product.getDetails()} + شحن سريع (30 ريال)`;
  }

  get price() {
    return (this.product as any).price + 30;
  }
}

interface Command {
  execute(): Promise<void>;
  undo(): Promise<void>;
}

class CreateOrderCommand implements Command {
  constructor(
    private orderService: OrderService,
    private orderData: any,
  ) {}

  async execute() {
    console.log("إنشاء طلب جديد");
    await this.orderService.create(this.orderData);
  }

  async undo() {
    console.log("إلغاء الطلب");
    await this.orderService.cancel(this.orderData.id);
  }
}

class OrderInvoker {
  private history: Command[] = [];

  async executeCommand(command: Command) {
    await command.execute();
    this.history.push(command);
  }

  async undoLastCommand() {
    const command = this.history.pop();
    if (command) await command.undo();
  }
}

class EcommerceSystem {
  private notifier = new OrderSubject();
  private invoker = new OrderInvoker();

  constructor() {
    this.notifier.attach(new EmailNotifier());
    this.notifier.attach(new SMSNotifier());
  }

  async placeOrder(orderData: any, paymentType: string) {
    const product = ProductFactory.create(orderData.productType, orderData);

    const decorated = new GiftWrapping(new ExpressShipping(product));

    const payment = new PaymentMethodFactory.create(paymentType);
    const paid = await payment.pay(decorated.price);

    if (paid) {
      const cmd = new CreateOrderCommand(orderService, {
        ...orderData,
        product: decorated,
      });
      await this.invoker.executeCommand(cmd);
      this.notifier.notify("order:created", { orderId: orderData.id });
    }
  }
}