sleeping-barber

barber.py

from threading import Thread
from time import sleep


def threaded(func):
  def wrapper(*args, **kwargs):
    thread = Thread(target=func, args=args, kwargs=kwargs)
    thread.start()
    return thread
  return wrapper

class Barber:
    def __init__(self, name):
      self.name = name
      self.queue = []
      self.is_working = False

    @threaded
    def work(self):
      self.is_working = True
      print(f"{self.name} is working")
      while self.queue:
        customer = self.queue.pop(0)
        print(f"{self.name} is cutting hair of {customer.name}")
        sleep(3)
        customer.is_done = True
      print(f"{self.name} is idle")
      self.is_working = False

    @threaded
    def add_customer(self, customer):
      self.queue.append(customer)
      print(f"{customer.name} is waiting in the queue")
      if not self.is_working:
        self.work()

customer.py

class Customer:
  def __init__(self, name, arrival_time) -> None:
    self.name = name
    self.arrival_time = arrival_time

input.txt

0
2
2
10
11
18
23

main.py

from barber import Barber
from customer import Customer
from threading import Thread
from time import sleep


def run(barber: Barber, file: str):
  customer_arrival_times = [int(t.strip()) for t in open(file, 'r').readlines()]

  for i, time in enumerate(customer_arrival_times):
    customer = Customer(chr(65 + i), time)
    barber.add_customer(customer)
    if i < len(customer_arrival_times) - 1:
      sleep(customer_arrival_times[i + 1] - time)


if __name__ == '__main__':
  barber = Barber("Billu")
  thread = Thread(target=run, args=(barber, 'input.txt'))
  thread.start()
  thread.join()