class ProductFactory:
    @staticmethod
    def create_product(product_type, **kwargs):
        if product_type == "physical":
            return PhysicalProduct(**kwargs)
        elif product_type == "digital":
            return DigitalProduct(**kwargs)
        elif product_type == "subscription":
            return SubscriptionProduct(**kwargs)

class OrderBuilder:
    def __init__(self):
        self.order = Order()

    def add_product(self, product):
        self.order.products.append(product)
        return self

    def set_customer(self, customer):
        self.order.customer = customer
        return self

    def build(self):
        return self.order

class OrderProcessorDecorator:
    def __init__(self, processor):
        self.processor = processor

    def process(self, order):
        return self.processor.process(order)

class TaxCalculatorDecorator(OrderProcessorDecorator):
    def process(self, order):
        result = self.processor.process(order)
        # add tax calculation
        return result

class OrderManagementFacade:
    def __init__(self):
        self.inventory = InventoryService()
        self.payment = PaymentService()
        self.shipping = ShippingService()

    def place_order(self, order):
        self.inventory.reserve_items(order.products)
        result = self.payment.process_payment(order)
        if result.success:
            self.shipping.schedule_delivery(order)
        return result

class PaymentProcessor:
    def __init__(self):
        self.strategy = None

    def set_payment_strategy(self, strategy):
        self.strategy = strategy

    def process_payment(self, order):
        return self.strategy.pay(order.total_amount)

class Order(Subject):
    def __init__(self):
        super().__init__()
        self._status = "pending"

    @status.setter
    def status(self, new_status):
        self._status = new_status
        self.notify(f"Order status changed to {new_status}")

class PlaceOrderCommand(Command):
    def __init__(self, order_service, order):
        self.order_service = order_service
        self.order = order

    def execute(self):
        return self.order_service.place_order(self.order)

    def undo(self):
        return self.order_service.cancel_order(self.order)