#!/usr/bin/env python3

# Libervia AsyncIO helper methods
# Copyright (C) 2009-2023 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import asyncio
from typing import Any, Coroutine

from libervia.backend.core import log as logging

log = logging.getLogger(__name__)
background_tasks = set()


def _on_task_done(task: asyncio.Future) -> None:
    """Callback function to execute when a task is done.

    @param task: The completed task.
        Note: The function removes the task from the tracking set and logs any exceptions
        that might have occurred.
    """
    background_tasks.discard(task)
    e = task.exception()
    if e is not None:
        exc_info = (type(e), e, e.__traceback__)
        log.error("Task failed:", exc_info=exc_info)


def run_async(async_method: Coroutine | asyncio.Future) -> None:
    """Schedules and tracks an asynchronous method.

    @param async_method: The method to be scheduled for execution.
        Note: The function keeps a strong reference to the task to prevent it from being
        garbage-collected. In case of task failure, logs the error.
        cf. https://docs.python.org/3/library/asyncio-task.html#asyncio.create_task
    """
    if isinstance(async_method, asyncio.Future):
        task = asyncio.ensure_future(async_method)
    else:
        task = asyncio.create_task(async_method)

    background_tasks.add(task)
    task.add_done_callback(_on_task_done)