test.py

from ctypes import Structure, windll, c_uint, sizeof, byref
from threading import Thread, Event
from pynput import keyboard
from time import sleep

keys = []
message = ' '

# LAST INPUT INFO
class LASTINPUTINFO(Structure):
    _fields_ = [
        ('cbSize', c_uint),
        ('dwTime', c_uint),
        ]

def get_idle_duration():
    while True:
        lastInputInfo = LASTINPUTINFO()
        lastInputInfo.cbSize = sizeof(lastInputInfo)
        windll.user32.GetLastInputInfo(byref(lastInputInfo))
        millis = windll.kernel32.GetTickCount() - lastInputInfo.dwTime
        millis = millis / 1000.0
        print(f'\t{millis}')
        sleep(1)
        if int(millis) == 3: # every 3 sec user is AFK, trigger event.set()
            print(f'\t{millis}')
            event.set()

def foo(k):
    event.wait()
    print(f'Event set: {event.is_set()}')
    print(f'{k}')
    print('PROCESS FINISHED\n')
    sleep(3)
    event.clear()

def write_keys(keys):
    global message
    for key in keys:
        k = str(key).replace("'", "")
        print(k, len(k))
        message += k # concatenate keys
    if (len(message)) >= 3:
        foo(message)

def on_press(key):
    global keys
    keys.append(key)
    write_keys(keys)
    keys = []

if __name__ == "__main__":
    event = Event()

    listener = keyboard.Listener(on_press=on_press)
    timer = Thread(target=get_idle_duration)

    listener.start()
    timer.start()