# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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.
"""remove empty filters

Revision ID: afb7730f6a9c
Revises: c5756bec8b47
Create Date: 2018-06-07 09:52:54.535961

"""

# revision identifiers, used by Alembic.
revision = 'afb7730f6a9c'
down_revision = 'c5756bec8b47'

from alembic import op
import json
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, Text

from superset import db

Base = declarative_base()


class Slice(Base):
    __tablename__ = 'slices'

    id = Column(Integer, primary_key=True)
    params = Column(Text)


def upgrade():
    bind = op.get_bind()
    session = db.Session(bind=bind)

    for slc in session.query(Slice).all():
        try:
            params = json.loads(slc.params)

            for key in ('filters', 'having_filters', 'extra_filters'):
                value = params.get(key)

                # Remove empty in/not-in filters.
                if value:
                    params[key] = [
                        x for x in value
                        if not (x['op'] in ('in', 'not in') and not x['val'])
                    ]

            slc.params = json.dumps(params, sort_keys=True)
        except Exception:
            pass

    session.commit()
    session.close()


def downgrade():
    pass
