path: root/slack/task.py

from __future__ import annotations

from typing import (
    Any,
    Awaitable,
    Coroutine,
    Generator,
    List,
    Optional,
    Tuple,
    TypeVar,
    Union,
)
from uuid import uuid4

import weechat

from slack.shared import shared
from slack.util import get_callback_name

T = TypeVar("T")


class Future(Awaitable[T]):
    def __init__(self, future_id: Optional[str] = None):
        if future_id is None:
            self.id = str(uuid4())
        else:
            self.id = future_id
        self.result: Optional[T] = None

    def __await__(self) -> Generator[Future[T], T, T]:
        self.result = yield self
        return self.result


class FutureProcess(Future[Tuple[str, int, str, str]]):
    pass


class FutureTimer(Future[Tuple[int]]):
    pass


class Task(Future[T]):
    def __init__(self, coroutine: Coroutine[Future[Any], Any, T]):
        super().__init__()
        self.coroutine = coroutine


def weechat_task_cb(data: str, *args: Any) -> int:
    future = shared.active_futures.pop(data)
    future.result = args
    tasks = shared.active_tasks.pop(data)
    for task in tasks:
        task_runner(task, args)
    return weechat.WEECHAT_RC_OK


def task_runner(task: Task[Any], response: Any):
    while True:
        try:
            future = task.coroutine.send(response)
            if future.result is not None:
                response = future.result
            else:
                shared.active_tasks[future.id].append(task)
                shared.active_futures[future.id] = future
                break
        except StopIteration as e:
            task.result = e.value
            if task.id in shared.active_tasks:
                tasks = shared.active_tasks.pop(task.id)
                for active_task in tasks:
                    task_runner(active_task, e.value)
            if task.id in shared.active_futures:
                del shared.active_futures[task.id]
            break


def create_task(coroutine: Coroutine[Future[Any], Any, T]) -> Task[T]:
    task = Task(coroutine)
    task_runner(task, None)
    return task


async def gather(*requests: Union[Future[T], Coroutine[Any, Any, T]]) -> List[T]:
    # TODO: Should probably propagate first exception
    tasks = [
        create_task(request) if isinstance(request, Coroutine) else request
        for request in requests
    ]
    return [await task for task in tasks]


async def sleep(milliseconds: int):
    future = FutureTimer()
    weechat.hook_timer(
        milliseconds, 0, 1, get_callback_name(weechat_task_cb), future.id
    )
    return await future