# Copyright (C) 2010-2020 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# 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 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/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

import socket
import logging

import rhodecode
from zope.cachedescriptors.property import Lazy as LazyProperty
from rhodecode.lib.celerylib.loader import (
    celery_app, RequestContextTask, get_logger)
from rhodecode.lib.statsd_client import StatsdClient

async_task = celery_app.task


log = logging.getLogger(__name__)


class ResultWrapper(object):
    def __init__(self, task):
        self.task = task

    @LazyProperty
    def result(self):
        return self.task


def run_task(task, *args, **kwargs):
    import celery
    log.debug('Got task `%s` for execution, celery mode enabled:%s', task, rhodecode.CELERY_ENABLED)
    if task is None:
        raise ValueError('Got non-existing task for execution')

    exec_mode = 'sync'
    allow_async = True

    # if we're already in a celery task, don't allow async execution again
    # e.g task within task
    in_task = celery.current_task
    if in_task:
        log.debug('This task in in context of another task: %s, not allowing another async execution', in_task)
        allow_async = False
        if kwargs.pop('allow_subtask', False):
            log.debug('Forced async by allow_async=True flag')
            allow_async = True

    t = None
    if rhodecode.CELERY_ENABLED and allow_async:

        try:
            t = task.apply_async(args=args, kwargs=kwargs)
            log.debug('executing task %s:%s in async mode', t.task_id, task)
        except socket.error as e:
            if isinstance(e, IOError) and e.errno == 111:
                log.error('Unable to connect to celeryd `%s`. Sync execution', e)
            else:
                log.exception("Exception while connecting to celeryd.")
        except KeyError as e:
            log.error('Unable to connect to celeryd `%s`. Sync execution', e)
        except Exception as e:
            log.exception(
                "Exception while trying to run task asynchronous. "
                "Fallback to sync execution.")

    else:
        log.debug('executing task %s:%s in sync mode', 'TASK', task)
        statsd = StatsdClient.statsd
        if statsd:
            task_repr = getattr(task, 'name', task)
            statsd.incr('rhodecode_celery_task_total', tags=[
                'task:{}'.format(task_repr),
                'mode:sync'
            ])

    # we got async task, return it after statsd call
    if t:
        return t
    return ResultWrapper(task(*args, **kwargs))