How to make program that runs a timer and the code separately but interacts with it?-CodePudding

I am trying to make a program loop with a timer that runs separately which for every iteration, the code continues where the timer countdown is left.

I drawed this pseudo code. It is the main idea on what i am trying to achieve (please play close attention). Basically while the timer is going, i want the next iteration to jump to where the timer currently is.

I tried writing a code, of course its wrong

import time
import threading

def scan_if_won():
    #returns True or False

def wait_for_start_signal():
    #returns True or False
    
def main():
    print("Action 0") 
    while True:
            time.sleep(20) #or any other timer function
            while wait_for_start_signal() == False: #usually takes 6-9 seconds, we never know exact time
                    start = wait_for_start_signal()
                    if start == True:
                        break
                    
            #reset timer, countdown from 20
                    
            time.sleep(3)
            result = scan_if_won() #this scan is not instant, can take from 1 to 2 seconds
                if result == False
                    print("Action 1") 
                if result == True
                    print("Action 2")

            #Now somehow, at next iteration, time.sleep() value should be the 20 - 3 - scan_if_won() time 
            
main()

Was thinking of implementing threading but i have no idea how to start the thread from inside loop, kill it (if needed) and share variables (timer current value) between threads while being in a loop. Please look at my pseudo code again for fully understanding my issue. Thanks

CodePudding user response：

I think below code solve the problem if no bug. Event() class is very usefull for this kind of problems. I modified a little your code.

import time
import threading

def scan_if_won():
    time.sleep(2)
    return False

def wait_for_start_signal():
    time.sleep(7)
    return True

def check_start_signal(time):
    event2.wait(timeout=time)
    event2.clear()
    while 1:
        start=wait_for_start_signal()
        if start:
            event.set()
            return


def main():
    print("Action 0")
    while True:

            try:
                t # is thread (t) created ?
                event.wait()
                event.clear()

            except UnboundLocalError:
                check_start_signal(20)

            t=threading.Thread(target=check_start_signal,args=(20,))
            t.start()

            start=time.time()
            time.sleep(3)
            result = scan_if_won() #this scan is not instant, can take from 1 to 2 seconds
            if result == False:
                print("Action 1")
            if result == True:
                print("Action 2")
            passed=time.time()-start

            time.sleep(20-passed)

            event2.set()
            #Now somehow, at next iteration, time.sleep() value should be the 20 - 3 - scan_if_won() time

event=threading.Event()
event2=threading.Event()
main()

CodePudding user response：

normal in c# we have "events" so u should google it for the pyhton.