# Copyright 2017 Huawei Technologies Co.,LTD.
# 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.

import oslo_messaging as messaging

from oslo_config import cfg
from oslo_messaging.rpc import dispatcher

from cyborg import context as cyborg_context
from cyborg.common import exception


CONF = cfg.CONF
TRANSPORT = None
NOTIFICATION_TRANSPORT = None
NOTIFIER = None

ALLOWED_EXMODS = [
    exception.__name__,
]
EXTRA_EXMODS = []


def init(conf):
    global TRANSPORT, NOTIFICATION_TRANSPORT, NOTIFIER
    exmods = get_allowed_exmods()
    TRANSPORT = messaging.get_rpc_transport(conf, allowed_remote_exmods=exmods)
    NOTIFICATION_TRANSPORT = messaging.get_notification_transport(
        conf, allowed_remote_exmods=exmods
    )
    serializer = RequestContextSerializer(messaging.JsonPayloadSerializer())
    NOTIFIER = messaging.Notifier(
        NOTIFICATION_TRANSPORT, serializer=serializer, topics=['notifications']
    )


def cleanup():
    global TRANSPORT, NOTIFICATION_TRANSPORT, NOTIFIER
    assert TRANSPORT is not None
    assert NOTIFICATION_TRANSPORT is not None
    assert NOTIFIER is not None
    TRANSPORT.cleanup()
    NOTIFICATION_TRANSPORT.cleanup()
    TRANSPORT = NOTIFICATION_TRANSPORT = NOTIFIER = None


def set_defaults(control_exchange):
    messaging.set_transport_defaults(control_exchange)


def add_extra_exmods(*args):
    EXTRA_EXMODS.extend(args)


def clear_extra_exmods():
    del EXTRA_EXMODS[:]


def get_allowed_exmods():
    return ALLOWED_EXMODS + EXTRA_EXMODS


class RequestContextSerializer(messaging.Serializer):
    def __init__(self, base):
        self._base = base

    def serialize_entity(self, context, entity):
        if not self._base:
            return entity
        return self._base.serialize_entity(context, entity)

    def deserialize_entity(self, context, entity):
        if not self._base:
            return entity
        return self._base.deserialize_entity(context, entity)

    def serialize_context(self, context):
        return context.to_dict()

    def deserialize_context(self, context):
        return cyborg_context.RequestContext.from_dict(context)


def get_client(target, version_cap=None, serializer=None):
    assert TRANSPORT is not None
    serializer = RequestContextSerializer(serializer)
    return messaging.get_rpc_client(
        TRANSPORT, target, version_cap=version_cap, serializer=serializer
    )


def get_server(target, endpoints, serializer=None):
    assert TRANSPORT is not None
    access_policy = dispatcher.DefaultRPCAccessPolicy
    serializer = RequestContextSerializer(serializer)
    return messaging.get_rpc_server(
        TRANSPORT,
        target,
        endpoints,
        serializer=serializer,
        access_policy=access_policy,
    )


def get_notifier(service=None, host=None, publisher_id=None):
    assert NOTIFIER is not None
    if not publisher_id:
        publisher_id = "%s.%s" % (service, host or CONF.host)
    return NOTIFIER.prepare(publisher_id=publisher_id)
