#!/usr/bin/env python
#
# Copyright 2016 the original author or authors.
#
# Code adapted from https://github.com/choppsv1/netconf
#
# 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 structlog
from base.commit import Commit
from base.copy_config import CopyConfig
from base.delete_config import DeleteConfig
from base.discard_changes import DiscardChanges
from base.edit_config import EditConfig
from base.get import Get
from base.get_config import GetConfig
from base.lock import Lock
from base.unlock import UnLock
from base.close_session import CloseSession
from base.kill_session import KillSession
from ext.get_voltha import GetVoltha
from netconf import NSMAP, qmap
import netconf.nc_common.error as ncerror

log = structlog.get_logger()
from lxml import etree


class RpcFactory:
    instance = None

    def __init__(self):
        self.rpc_map = {}
        # TODO:  This will be loaded after the yang modules have been
        # generated from proto files
        self.register_rpc('{urn:opencord:params:xml:ns:voltha:ietf-voltha}',
                          'VolthaGlobalService', 'GetVoltha', GetVoltha)
        self.register_rpc('{urn:opencord:params:xml:ns:voltha:ietf-voltha}',
                          'any', 'any', GetVoltha)

    def _get_key(self, namespace, service, name):
        return ''.join([namespace, service, name])

    def register_rpc(self, namespace, service, name, klass):
        key = self._get_key(namespace, service, name)
        if key not in self.rpc_map.keys():
            self.rpc_map[key] = klass

    def get_handler(self, namespace, service, name):
        key = self._get_key(namespace, service, name)
        if key in self.rpc_map.keys():
            return self.rpc_map[key]

    def get_rpc_handler(self, rpc_node, msg, grpc_channel, session):
        try:
            msg_id = rpc_node.get('message-id')
            log.info("Received-rpc-message-id", msg_id=msg_id)

        except (TypeError, ValueError):
            raise ncerror.SessionError(msg,
                                       "No valid message-id attribute found")

        log.info("rpc-node", node=etree.tostring(rpc_node, pretty_print=True))

        # Get the first child of rpc as the method name
        rpc_method = rpc_node.getchildren()
        if len(rpc_method) != 1:
            log.error("badly-formatted-rpc-method", msg_id=msg_id)
            raise ncerror.BadMsg(rpc_node)

        rpc_method = rpc_method[0]

        if rpc_method.prefix is None:
            log.error("rpc-method-has-no-prefix", msg_id=msg_id)
            raise ncerror.BadMsg(rpc_node)

        try:
            # extract the namespace, service and name
            namespace = ''.join(
                ['{', rpc_method.nsmap[rpc_method.prefix], '}'])
            # rpc_name = rpc_method.tag.replace(qmap('nc'), "")
            rpc = rpc_method.tag.replace(namespace, "").split('-')
            rpc_service = rpc[0]
            rpc_name = rpc[1]
            log.info("rpc-request",
                     namespace=namespace,
                     service=rpc_service,
                     name=rpc_name)
        except Exception as e:
            log.error("rpc-parsing-error", exception=repr(e))
            raise ncerror.BadMsg(rpc_node)

        class_handler = self.get_handler(namespace, rpc_service, rpc_name)
        if class_handler is None:
            # TODO: for now just assume anything in voltha namespace will be
            #  handled by the same api
            class_handler = self.get_handler(namespace, 'any', 'any')

        voltha_method_ref = ''.join([rpc_service, '-', rpc_name])
        if class_handler is not None:
            return class_handler(rpc_node, rpc_method, voltha_method_ref,
                                 grpc_channel, session)

        log.error("rpc-not-implemented", rpc=rpc_name)

    rpc_class_handlers = {
        'getvoltha': GetVoltha,
        'get-config': GetConfig,
        'get': Get,
        'edit-config': EditConfig,
        'copy-config': CopyConfig,
        'delete-config': DeleteConfig,
        'commit': Commit,
        'lock': Lock,
        'unlock': UnLock,
        'close-session': CloseSession,
        'kill-session': KillSession
    }


def get_rpc_factory_instance():
    if RpcFactory.instance == None:
        RpcFactory.instance = RpcFactory()
    return RpcFactory.instance


if __name__ == '__main__':
    fac = get_rpc_factory_instance()
    fac.register_rpc('urn:opencord:params:xml:ns:voltha:ietf-voltha',
                     'VolthaGlobalService', 'GetVoltha', GetVoltha)
    rpc = fac.get_handler('urn:opencord:params:xml:ns:voltha:ietf-voltha',
                          'VolthaGlobalService', 'GetVoltha')
    # rpc = fac.rpc_class_handlers.get('getvoltha', None)
    print rpc(None, None, None, None)