from threading import Thread, Event
import time


class Timer(Thread):
    """Call a function after a specified number of seconds:

            t = Timer(30.0, f, args=None, kwargs=None)
            t.start()
            t.cancel()     # stop the timer's action if it's still waiting

    """

    def __init__(self, internal, function, args=None, kwargs=None):
        Thread.__init__(self)
        self._internal = internal
        self._function = function
        self._args = args if args is not None else []
        self._kwargs = kwargs if kwargs is not None else {}
        self._finished = Event()
        self._reset = False

    def cancel(self):
        """Stop the timer."""
        self._finished.set()

    def reset(self):
        """Reset the timer"""
        self._reset = True
        self._finished.set()

    def run(self):
        while True:
            self._finished.wait(self._internal)
            if not self._finished.is_set():
                self._function(*self._args, **self._kwargs)
            if self._reset:
                """Reset the timer"""
                self._reset = False
                self._finished.clear()
                continue
            return


"""Example"""


def ping():
    print("ping, at " + str(time.time()))


def main():
    timer = Timer(3.0, ping)
    print(time.time())
    timer.start()
    time.sleep(1.3)
    print(time.time())
    timer.reset()


if __name__ == '__main__':
    main()