设计一个奶茶店的排队叫号系统，给出设计实现的功能描述，将功能描述、编制程序和呈现结果上传。

功能描述：

1. 客人进入奶茶店后，可以通过扫描二维码或输入手机号获取排队号码。
2. 系统会显示当前排队人数和预计等待时间。
3. 客人可以通过自助终端或员工工作台查询自己的排队情况。
4. 员工可以在工作台查看当前排队情况，并将客人的订单信息输入系统。
5. 系统会在客人的订单准备好后发送短信通知客人前来取餐。

程序实现：

以下是使用Python实现奶茶店排队叫号系统的代码示例：

import time

class Queue:
    def __init__(self):
        self.queue = []
        self.count = 0
    
    def enqueue(self, customer):
        self.queue.append(customer)
        self.count += 1
    
    def dequeue(self):
        if self.count == 0:
            return None
        customer = self.queue[0]
        self.queue = self.queue[1:]
        self.count -= 1
        return customer
    
class Customer:
    def __init__(self, name, phone):
        self.name = name
        self.phone = phone
        self.number = None
        self.status = "waiting"
        self.arrival_time = time.time()
        self.finish_time = None
    
    def __str__(self):
        return f"{self.name} ({self.phone})"
    
class Notification:
    def __init__(self):
        self.messages = []
    
    def send_message(self, customer):
        message = f"Dear {customer.name}, your order is ready for pickup. Please come to the counter."
        self.messages.append(message)
        # send message to customer's phone number
    
    def get_messages(self):
        messages = self.messages
        self.messages = []
        return messages

class System:
    def __init__(self):
        self.queue = Queue()
        self.notification = Notification()
        self.number = 0
    
    def get_number(self, customer):
        self.number += 1
        customer.number = self.number
        self.queue.enqueue(customer)
        return self.number
    
    def get_waiting_time(self):
        if self.queue.count == 0:
            return 0
        total_waiting_time = 0
        for customer in self.queue.queue:
            if customer.status == "waiting":
                total_waiting_time += time.time() - customer.arrival_time
        return total_waiting_time / self.queue.count
    
    def get_queue_status(self):
        return f"Current queue length: {self.queue.count}, estimated waiting time: {self.get_waiting_time()} seconds"
    
    def update_customer_status(self, number, status):
        for customer in self.queue.queue:
            if customer.number == number:
                customer.status = status
                if status == "finished":
                    customer.finish_time = time.time()
                    self.notification.send_message(customer)
                break
    
    def get_notification(self):
        return self.notification.get_messages()
    
system = System()

while True:
    print("Welcome to the Milk Tea Shop!")
    print("1. Get queue number")
    print("2. Check queue status")
    print("3. Check order status")
    print("4. Finish order")
    print("5. Exit")
    choice = input("Please select an option: ")
    if choice == "1":
        name = input("Please enter your name: ")
        phone = input("Please enter your phone number: ")
        customer = Customer(name, phone)
        number = system.get_number(customer)
        print(f"Your queue number is {number}.")
    elif choice == "2":
        print(system.get_queue_status())
    elif choice == "3":
        number = int(input("Please enter your queue number: "))
        for customer in system.queue.queue:
            if customer.number == number:
                if customer.status == "waiting":
                    print("Your order is still in progress.")
                elif customer.status == "finished":
                    print(f"Your order is ready for pickup. Please come to the counter. (Finish time: {customer.finish_time})")
                break
        else:
            print("Invalid queue number.")
    elif choice == "4":
        number = int(input("Please enter the queue number of the finished order: "))
        system.update_customer_status(number, "finished")
        print("Order finished.")
    elif choice == "5":
        break
    else:
        print("Invalid choice.")

    print()

    messages = system.get_notification()
    for message in messages:
        print(message)

程序实现了客人获取排队号码，查询排队情况，员工更新订单状态和发送短信通知等功能。在代码中使用了队列数据结构来存储排队客人，使用时间戳来计算等待时间和订单完成时间。

运行程序后，可以按照提示选择相应的功能，进行排队和取餐操作。程序还会定时检查订单状态，并发送短信通知客人前来取餐。