#!/usr/bin/env python
# FIT2022 Lab 2 example7.py
import time
from threading import *
from fit2022io import *
ev0 = Event(); ev0.set()
ev1 = Event(); ev1.clear()
ev2 = Event(); ev2.clear()
ev3 = Event(); ev3.clear()

running = 1; i = 0; di = 0; dim1 = 0;

class Program(Thread):
   def __init__(self,label):
      Thread.__init__(self,name=label)
      self.label = label
   def start(self):
      Thread.start(self)
   def run(self):
      global running,i,di,dim1,k
      global ev0,ev1,ev2,ev3
      while running:
         if self.label == "next i":
            ev0.wait(); ev0.clear(); i = i+1; ev1.set()
         elif self.label == "double i":
            ev1.wait(); ev1.clear(); di = 2*i; ev2.set()
         elif self.label == "minus 1":
            ev2.wait(); ev2.clear(); dim1 = di - 1; ev3.set()
         else:
            ev3.wait(); ev3.clear(); 
            printf("i=%d, 2*i=%d, 2*i-1=%d\n",i,di,dim1)
            if i>=20:
               running = 0
            ev0.set()
         
process1 = Program("next i")
process2 = Program("double i")
process3 = Program("minus 1")
process4 = Program("print")

process1.start()
process2.start()
process3.start()
process4.start()

process1.join()
process2.join()
process3.join()
process4.join()