/*
 * 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.
 */

package software.amazon.documentdb.jdbc.calcite.adapter;

import org.apache.calcite.adapter.enumerable.EnumerableConvention;
import org.apache.calcite.plan.RelTraitSet;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.convert.ConverterRule;

/**
 * Rule to convert a relational expression from
 * {@link DocumentDbRel#CONVENTION} to {@link EnumerableConvention}.
 */
public class DocumentDbToEnumerableConverterRule extends ConverterRule {
    /** Singleton instance of MongoToEnumerableConverterRule. */
    public static final ConverterRule INSTANCE = Config.INSTANCE
            .withConversion(RelNode.class, DocumentDbRel.CONVENTION,
                    EnumerableConvention.INSTANCE, "MongoToEnumerableConverterRule")
            .withRuleFactory(DocumentDbToEnumerableConverterRule::new)
            .toRule(DocumentDbToEnumerableConverterRule.class);

    /** Called from the Config. */
    protected DocumentDbToEnumerableConverterRule(final Config config) {
        super(config);
    }

    @Override public RelNode convert(final RelNode rel) {
        final RelTraitSet newTraitSet = rel.getTraitSet().replace(getOutConvention());
        return new DocumentDbToEnumerableConverter(rel.getCluster(), newTraitSet, rel);
    }
}