#    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.db import model_base
import sqlalchemy as sa
from sqlalchemy import orm

from neutron.db.models import agent as agent_model

LOWEST_BINDING_INDEX = 1


class RouterL3AgentBinding(model_base.BASEV2):
    """Represents binding between neutron routers and L3 agents."""

    __table_args__ = (
        sa.UniqueConstraint(
            'router_id', 'binding_index',
            name='uniq_router_l3_agent_binding0router_id0binding_index0'),
        model_base.BASEV2.__table_args__
    )

    router_id = sa.Column(sa.String(36),
                          sa.ForeignKey("routers.id", ondelete='CASCADE'),
                          primary_key=True)
    l3_agent = orm.relation(agent_model.Agent)
    l3_agent_id = sa.Column(sa.String(36),
                            sa.ForeignKey("agents.id", ondelete='CASCADE'),
                            primary_key=True)
    binding_index = sa.Column(sa.Integer, nullable=False,
                              server_default=str(LOWEST_BINDING_INDEX))