#
# This file is part of PCAP BGP Parser (pbgpp)
#
# Copyright 2016-2017 DE-CIX Management GmbH
# Author: Tobias Hannaske <tobias.hannaske@de-cix.net>
#
# 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 pbgpp.Output.Filter import BGPFilter
from pbgpp.BGP.Statics import BGPStatics


class NLRIFilter(BGPFilter):
    def __init__(self, values=[]):
        BGPFilter.__init__(self, values)

    def apply(self, message):
        try:
            # We first need to make that we are currently handling an UPDATE message
            if message.type is not BGPStatics.MESSAGE_TYPE_UPDATE:
                # Skip messages that are no UPDATE messages
                return None

            if len(message.nlri) > 0:
                # NLRI is containing values
                for route in message.nlri:

                    for value in self.values:
                        negated = False
                        if value[0:1] == "~":
                            negated = True
                            value = value[1:]

                        if not negated and route.prefix_string == value:
                            return message

                        if negated and route.prefix_string != value:
                            return message

            # Searched value was not found
            return None
        except Exception as e:
            # On error the filtering was not successful (due to wrong fields, etc.)
            return None
