Implementing Queue Using Python

class Queue:
  def __init__(self):
    self.items = []
    
  def isEmpty(self):
    return self.items == []
    
  def enqueue(self, item):
    self.items.insert(0, item)
    
  def dequeue(self):
    return self.items.pop()
    
  def size(self):
    return len(self.items)
    

# application1 using Queue: Hot Potato Simulation
def hotPotato(namelist, num):
  simqueue = Queue()
  for name in namelist:
    simqueue.enqueue(name)
    
  while simqueue.size() > 1:
    for i in range(num):
      simqueue.enqueue(simqueue.dequeue())
      
    simqueue.dequeue()
    
  return simqueue.dequeue()


# application2 using Queue: Print Tasks Simulation
class Printer:
  def __init__(self, ppm):
    self.pagerate = ppm
    self.currentTask = None
    self.timeRemaining = 0
    
  def tick(self):
    if self.currentTask != None:
      self.timeRemaining = self.timeRemaining - 1
      if self.timeRemaining <= 0:
        self.currentTask = None
        
  def busy(self):
    return self.currentTask != None
    
  def startNext(self, newtask):
    self.currentTask = newtask
    self.timeRemaining = newtask.getPages() * 60 / self.pagerate

import random

class Task:
  def __init__(self, time):
    self.timestamp = time
    self.pages = random.randrange(1, 21)
  
  def getStamp(self):
    return self.timestamp
  
  def getPages(self):
    return self.pages
    
  def waitTime(self, currentTime):
    return currentTime - self.timestamp

def simulation(numSeconds, pagesPerMinute):
  labprinter = Printer(pagesPerMinute)
  printQueue = Queue()
  waitingtimes = []
  
  for currentSecond in range(numSeconds):
    if newPrintTask():
      task = Task(currentSecond)
      printQueue.enqueue(task)
      
    if (not labprinter.busy()) and (not printQueue.isEmpty()):
      nexttask = printQueue.dequeue()
      waitingtimes.append(nexttask.waitTime(currentSecond))
      labprinter.startNext(nexttask)
      
    labprinter.tick()
    
  averageWait = sum(waitingtimes)/len(waitingtimes)
  print("Average Wait %6.2f secs %3d tasks remaining."%(averageWait, printQueue.size()))
  
def newPrintTask():
  return random.randrange(1, 181) == 180


def main():
  q = Queue()
  print(q.size())
  q.enqueue(8.4)
  print(q.size())
  print(q.dequeue())
  print(q.isEmpty())
  
  print(hotPotato(["Bill","David","Susan","Jane","Kent","Brad"], 7))
  
  for i in range(10):
    simulation(3600, 5)
  
main()