# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright (c) 2014, Oracle and/or its affiliates. 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.

#

# @author: Girish Moodalbail, Oracle, Inc.

#

import sqlalchemy as sa

from sqlalchemy.ext import declarative

from sqlalchemy import orm

from oslo.config import cfg

from quantum.context import ContextBase

from quantum.db import model_base

EVS_DB_BASE = declarative.declarative_base(cls=model_base.QuantumBaseV2)

EVS_DB_ENGINE = None

EVS_DB_MAKER = None

class EVSContext(ContextBase):

    @property

    def session(self):

        return self._session

    @session.setter

    def session(self, session):

        self._session = session

def configure_db():

    global EVS_DB_ENGINE

    if not EVS_DB_ENGINE:

        sql_connection = cfg.CONF.DATABASE.sql_connection

        if not sql_connection:

            sql_connection = 'sqlite:////var/lib/quantum/quantum.sqlite'

        EVS_DB_ENGINE = sa.create_engine(sql_connection, echo=True)

        EVS_DB_BASE.metadata.create_all(EVS_DB_ENGINE)

def get_session(autocommit=True, expire_on_commit=False):

    global EVS_DB_ENGINE, EVS_DB_MAKER

    assert EVS_DB_ENGINE

    if not EVS_DB_MAKER:

        EVS_DB_MAKER = orm.sessionmaker(bind=EVS_DB_ENGINE,

                                        autocommit=autocommit,

                                        expire_on_commit=expire_on_commit)

    return EVS_DB_MAKER()

def get_evs_context(context):

    """Overrides the Quantum DB session with EVS DB session"""

    evs_context = EVSContext.from_dict(context.to_dict())

    evs_context.session = get_session()

    return evs_context