#    Copyright 2015 Mirantis, Inc.
#
#    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 logging
import threading

from oslo_utils import eventletutils
import zmq

from oslo_messaging._drivers.zmq_driver import zmq_poller

LOG = logging.getLogger(__name__)

_threading = threading

if eventletutils.EVENTLET_AVAILABLE:
    import eventlet
    _threading = eventlet.patcher.original('threading')


class ThreadingPoller(zmq_poller.ZmqPoller):

    def __init__(self):
        self.poller = zmq.Poller()
        self.recv_methods = {}

    def register(self, socket, recv_method=None):
        if recv_method is not None:
            self.recv_methods[socket] = recv_method
        self.poller.register(socket, zmq.POLLIN)

    def poll(self, timeout=None):
        timeout = timeout * 1000  # zmq poller waits milliseconds
        sockets = None

        try:
            sockets = dict(self.poller.poll(timeout=timeout))
        except zmq.ZMQError as e:
            LOG.debug("Polling terminated with error: %s" % e)

        if not sockets:
            return None, None
        for socket in sockets:
            if socket in self.recv_methods:
                return self.recv_methods[socket](socket), socket
            else:
                return socket.recv_multipart(), socket

    def resume_polling(self, socket):
        pass  # Nothing to do for threading poller

    def close(self):
        pass  # Nothing to do for threading poller


class ThreadingExecutor(zmq_poller.Executor):

    def __init__(self, method):
        self._method = method
        super(ThreadingExecutor, self).__init__(
            _threading.Thread(target=self._loop))
        self._stop = _threading.Event()

    def _loop(self):
        while not self._stop.is_set():
            self._method()

    def execute(self):
        self.thread.start()

    def stop(self):
        self._stop.set()

    def wait(self):
        self.thread.join()