#    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 sqlalchemy import Column
from sqlalchemy import MetaData
from sqlalchemy import Table
from sqlalchemy import Text


BASE_TABLE_NAME = 'instance_extra'
NEW_COLUMN_NAME = 'vcpu_model'


def upgrade(migrate_engine):
    meta = MetaData()
    meta.bind = migrate_engine

    for prefix in ('', 'shadow_'):
        table = Table(prefix + BASE_TABLE_NAME, meta, autoload=True)
        new_column = Column(NEW_COLUMN_NAME, Text, nullable=True)
        if not hasattr(table.c, NEW_COLUMN_NAME):
            table.create_column(new_column)


def downgrade(migrate_engine):
    meta = MetaData()
    meta.bind = migrate_engine

    for prefix in ('', 'shadow_'):
        table = Table(prefix + BASE_TABLE_NAME, meta, autoload=True)
        if hasattr(table.c, NEW_COLUMN_NAME):
            getattr(table.c, NEW_COLUMN_NAME).drop()
