"""
Higher-level context managers for async pools

Copyright (C) 2020 nocturn9x

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""


import types
from .objects import Task
from .core import AsyncScheduler


class TaskManager:
    """
    An asynchronous context manager for giambio
    """

    def __init__(self, loop: AsyncScheduler) -> None:
        """
        Object constructor
        """

        self.loop = loop
        self.tasks = []  # We store a reference to all tasks, even the asleep ones!

    def spawn(self, func: types.FunctionType, *args):
        """
        Spawns a child task
        """

        task = Task(func(*args), func.__name__ or str(func), self)
        task.joiners = [self.loop.current_task]
        self.loop.tasks.append(task)
        self.loop.debugger.on_task_spawn(task)
        self.tasks.append(task)
        return task

    def spawn_after(self, func: types.FunctionType, n: int, *args):
        """
        Schedules a task for execution after n seconds
        """

        assert n >= 0, "The time delay can't be negative"
        task = Task(func(*args), func.__name__ or str(func), self)
        task.joiners = [self.loop.current_task]
        task.sleep_start = self.loop.clock()
        self.loop.paused.put(task, n)
        self.loop.debugger.on_task_schedule(task, n)
        self.tasks.append(task)
        return task

    async def __aenter__(self):
        return self

    async def __aexit__(self, exc_type: Exception, exc: Exception, tb):
        for task in self.tasks:
            await task.join()