#
#
#    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 neutron_lib.api import validators
from neutron_lib import constants
from neutron_lib.db import model_base
from neutron_lib.plugins.ml2 import api
from oslo_log import log as logging
import sqlalchemy as sa
from sqlalchemy import orm

from neutron.db import models_v2

LOG = logging.getLogger(__name__)

class VpcExtensionDriverBase(api.ExtensionDriver):
    _supported_extension_aliases = 'fake_extension'

    @property
    def extension_alias(self):
        return self._supported_extension_aliases

class VpcNetworkExtension(model_base.BASEV2):
    network_id = sa.Column(sa.String(36),
                           sa.ForeignKey('networks.id', ondelete="CASCADE"),
                           primary_key=True)
    value = sa.Column(sa.String(64))
    network = orm.relationship(
        models_v2.Network,
        backref=orm.backref('extension', cascade='delete', uselist=False,
                            lazy='joined'))

class VpcDbExtensionDriver(VpcExtensionDriverBase):
    def initialize(self):
        LOG.info("VpcDbExtensionDriver initialization complete")

    def _get_value(self, data, key):
        value = data[key]
        if not validators.is_attr_set(value):
            value = ''
        return value

    def process_create_network(self, plugin_context, data, result):
        session = plugin_context.session
        value = self._get_value(data, 'vpc_vni')
        record = VpcNetworkExtension(network_id=result['id'], value=value)
        session.add(record)
        result['vpc_vni'] = value

    def process_update_network(self, plugin_context, data, result):
        session = plugin_context.session
        record = (session.query(VpcNetworkExtension).
                  filter_by(network_id=result['id']).one())
        value = data.get('vpc_vni')
        if value and value != record.value:
            record.value = value
        result['vpc_vni'] = record.value

    def extend_network_dict(self, session, net_db, result):
        result['vpc_vni'] = net_db.extension.value