import structio
import random


async def waiter(ch: structio.ChannelReader):
    print("[waiter] Waiter is alive!")
    while True:
        print("[waiter] Awaiting events")
        try:
            evt: structio.Event = await ch.receive()
        except structio.ResourceClosed:
            break
        print("[waiter] Received event, waiting to be triggered")
        t = structio.clock()
        await evt.wait()
        print(f"[waiter] Event triggered after {structio.clock() - t:.2f} seconds")
    print("[waiter] Done!")


async def sender(ch: structio.Channel, n: int):
    print("[sender] Sender is alive!")
    async with ch:
        # Channel is automatically closed when exiting
        # the async with block
        for _ in range(n):
            print("[sender] Sending event")
            ev = structio.Event()
            await ch.send(ev)
            t = random.random()
            print(f"[sender] Sent event, sleeping {t:.2f} seconds")
            await structio.sleep(t)
            print("[sender] Setting the event")
            ev.set()
    print("[sender] Done!")


async def main(n: int):
    print("[main] Parent is alive")
    channel = structio.MemoryChannel(1)
    async with structio.create_pool() as pool:
        # Each end of the channel can be used independently,
        # and closing one does not also close the other (which
        # is why we pass the full channel object to our sender
        # so it can close both ends and cause the reader to catch
        # the closing exception and exit cleanly)
        pool.spawn(waiter, channel.reader)
        pool.spawn(sender, channel, n)
        print("[main] Children spawned")
    print("[main] Done!")


structio.run(main, 3)