import threading
from ctypes import *
import time
import subprocess

class ComputerMonitor:
	def __init__(self, callback):
		self.callback = callback
		self.started = False

	def monitor(self):
		self.monit_windows_lock()

	def monit_windows_lock(self):
		while True:
			process_name='LogonUI.exe'
			callall='TASKLIST'
			outputall=subprocess.check_output(callall)
			outputstringall=str(outputall)
			if process_name in outputstringall:
				print("Locked.")
				if self.callback:
					self.callback()
			else: 
			   pass
			   
			time.sleep(1)

	def start(self):
		monitor_threading = threading.Thread(target=self.monitor, args=())
		monitor_threading.start()
		self.started = True