# Copyright 2017 VMware, Inc.
# 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.


class ZoneFile(object):

    def __init__(self, origin, ttl, records):
        self.origin = origin
        self.ttl = ttl
        self.records = records

    def __str__(self):
        return str(self.__dict__)

    def __repr__(self):
        return str(self)

    def __eq__(self, other):
        return self.__dict__ == other.__dict__

    def __ne__(self, other):
        return not self.__eq__(other)

    @classmethod
    def from_text(cls, text):
        """Return a ZoneFile from a string containing the zone file contents"""
        # filter out empty lines and strip all leading/trailing whitespace.
        # this assumes no multiline records
        lines = [x.strip() for x in text.split('\n') if x.strip()]

        assert lines[0].startswith('$ORIGIN')
        assert lines[1].startswith('$TTL')

        return ZoneFile(
            origin=lines[0].split(' ')[1],
            ttl=int(lines[1].split(' ')[1]),
            records=[ZoneFileRecord.from_text(x) for x in lines[2:]],
        )


class ZoneFileRecord(object):

    def __init__(self, name, type, data):
        self.name = str(name)
        self.type = str(type)
        self.data = str(data)

    def __str__(self):
        return str(self.__dict__)

    def __repr__(self):
        return str(self)

    def __eq__(self, other):
        return self.__dict__ == other.__dict__

    def __ne__(self, other):
        return not self.__eq__(other)

    def __hash__(self):
        return hash(tuple(sorted(self.__dict__.items())))

    @classmethod
    def from_text(cls, text):
        """Create a ZoneFileRecord from a line of text of a zone file, like:
            mydomain.com. IN NS ns1.example.com.
        """
        # assumes records don't have a TTL between the name and the class.
        # assumes no parentheses in the record, all on a single line.
        parts = [x for x in text.split(' ', 4) if x.strip()]
        name, rclass, rtype, data = parts
        assert rclass == 'IN'
        return cls(name=name, type=rtype, data=data)