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

# Copyright 2018 Whitestack, LLC
# *************************************************************

# This file is part of OSM Monitoring module
# All Rights Reserved to Whitestack, LLC

# 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.

# For those usages not covered by the Apache License, Version 2.0 please
# contact: bdiaz@whitestack.com or glavado@whitestack.com
##
import asyncio
from typing import List, Callable

from osm_common import msgkafka, msglocal

from osm_mon.core.config import Config


class MessageBusClient:
    def __init__(self, config: Config, loop=None):
        if config.get('message', 'driver') == "local":
            self.msg_bus = msglocal.MsgLocal()
        elif config.get('message', 'driver') == "kafka":
            self.msg_bus = msgkafka.MsgKafka()
        else:
            raise Exception("Unknown message bug driver {}".format(config.get('section', 'driver')))
        self.msg_bus.connect(config.get('message'))
        if not loop:
            loop = asyncio.get_event_loop()
        self.loop = loop

    async def aioread(self, topics: List[str], callback: Callable = None, **kwargs):
        """
        Retrieves messages continuously from bus and executes callback for each message consumed.
        :param topics: List of message bus topics to consume from.
        :param callback: Async callback function to be called for each message received.
        :param kwargs: Keyword arguments to be passed to callback function.
        :return: None
        """
        await self.msg_bus.aioread(topics, self.loop, aiocallback=callback, **kwargs)

    async def aiowrite(self, topic: str, key: str, msg: dict):
        """
        Writes message to bus.
        :param topic: Topic to write to.
        :param key: Key to write to.
        :param msg: Dictionary containing message to be written.
        :return: None
        """
        await self.msg_bus.aiowrite(topic, key, msg, self.loop)

    async def aioread_once(self, topic: str):
        """
        Retrieves last message from bus.
        :param topic: topic to retrieve message from.
        :return: tuple(topic, key, message)
        """
        result = await self.msg_bus.aioread(topic, self.loop)
        return result
