from typing import Coroutine, Generator, Iterator, List, Tuple
from queue import PriorityQueue
from time import time, sleep

Task = Coroutine[ object, object, object ]

class Sched:
    def add( self, task: Task ) -> None:
        self.tasks.append( task.__await__() )

    def __init__( self ) -> None:
        self.tasks : List[ Iterator[ int ] ] = []
        self.queue : PriorityQueue[ Tuple[ float, int ] ]
        self.queue = PriorityQueue()

    class suspend:
        def __init__( self, n: int ) -> None:
            self.msec = n
        def __await__( self ) -> Generator[ int, None, None ]:
            yield self.msec

    def schedule( self, i: int ) -> None:
        try:
            task = self.tasks[ i ]
            delay = next( task )
            item = ( time() + delay / 1000, i )
            self.queue.put( item )
        except StopIteration:
            pass

    def run( self ) -> None:
        for i in range( len( self.tasks ) ):
            self.schedule( i )

        while not self.queue.empty():
            when, what = self.queue.get()
            pause = when - time()
            if pause > 0:
                sleep( pause )
            self.schedule( what )

import run_tests