# -*- coding: utf-8 -*-

#    Copyright (C) 2014 Yahoo! Inc. All Rights Reserved.
#
#    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.

from taskflow.engines.action_engine import engine
from taskflow.engines.worker_based import executor
from taskflow import storage as t_storage


class WorkerBasedActionEngine(engine.ActionEngine):
    """Worker based action engine.

    Specific backend configuration:

    :param exchange: broker exchange exchange name in which executor / worker
                     communication is performed
    :param url: broker connection url (see format in kombu documentation)
    :param topics: list of workers topics to communicate with (this will also
                   be learned by listening to the notifications that workers
                   emit).
    :keyword transport: transport to be used (e.g. amqp, memory, etc.)
    :keyword transport_options: transport specific options
    """

    _storage_factory = t_storage.SingleThreadedStorage

    def _task_executor_factory(self):
        if self._executor is not None:
            return self._executor
        return executor.WorkerTaskExecutor(
            uuid=self._flow_detail.uuid,
            url=self._conf.get('url'),
            exchange=self._conf.get('exchange', 'default'),
            topics=self._conf.get('topics', []),
            transport=self._conf.get('transport'),
            transport_options=self._conf.get('transport_options'))

    def __init__(self, flow, flow_detail, backend, conf, **kwargs):
        super(WorkerBasedActionEngine, self).__init__(
            flow, flow_detail, backend, conf)
        self._executor = kwargs.get('executor')