import threading, time
from .. util import log


class AnimationThreading:
    """
    AnimationThreading handles threading - and eventually multiprocessing - for
    Animation.
    """

    def __init__(self, runner, run):
        self.runner = runner
        self.run = run
        self.stop_event = threading.Event()
        self.thread = None
        self.frame_overrun = False
        self.sleep = time.sleep

    def set_project(self, project):
        self.sleep = project.clock.sleep

    def join(self, timeout=None):
        self.thread and self.thread.join(timeout)

    def is_alive(self):
        return self.thread and self.thread.is_alive()

    def cleanup(self):
        # if current thread is animation thread this was called
        # by the context manager and thread is therefore already stopped
        self.stop_event.set()

    def target(self):
        is_main = threading.current_thread() is threading.main_thread()
        log.debug('Animation starts on %s thread', 'main' if is_main else 'new')
        self.run()
        log.debug('Animation complete')

    def wait(self, wait_time, timestamps):
        if not wait_time:
            return

        elapsed_time = timestamps[-1] - timestamps[0]
        if elapsed_time >= wait_time + 0.001:
            logger = log.frame if self.frame_overrun else log.warning
            logger('Frame-time of %dms set, but took %dms',
                   1000 * wait_time, 1000 * elapsed_time)
            self.frame_overrun = True

        elif self.runner.threaded:
            self.stop_event.wait(wait_time - elapsed_time)

        else:
            self.sleep(wait_time - elapsed_time)

    def start(self):
        self.stop_event.clear()

        def start_thread(target):
            self.thread = threading.Thread(target=target, daemon=True)
            self.thread.start()

        if self.runner.main:
            if self.runner.threaded:
                start_thread(self.target)
                self.runner.main()

            else:
                start_thread(self.runner.main)
                self.target()

        elif self.runner.threaded:
            start_thread(self.target)

        else:
            self.target()

        self.thread and self.runner.main and self.thread.join()

    def stopped(self):
        # DEPRECATED
        return not self.is_alive()
