/**
 * 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
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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 org.apache.beam.sdk.extensions.sql.impl.rule;

import org.apache.beam.sdk.extensions.sql.impl.rel.BeamLogicalConvention;
import org.apache.beam.sdk.extensions.sql.impl.rel.BeamProjectRel;
import org.apache.calcite.plan.Convention;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.convert.ConverterRule;
import org.apache.calcite.rel.core.Project;
import org.apache.calcite.rel.logical.LogicalProject;

/** A {@code ConverterRule} to replace {@link Project} with {@link BeamProjectRel}. */
public class BeamProjectRule extends ConverterRule {
  public static final BeamProjectRule INSTANCE = new BeamProjectRule();

  private BeamProjectRule() {
    super(LogicalProject.class, Convention.NONE, BeamLogicalConvention.INSTANCE, "BeamProjectRule");
  }

  @Override
  public RelNode convert(RelNode rel) {
    final Project project = (Project) rel;
    final RelNode input = project.getInput();

    return new BeamProjectRel(
        project.getCluster(),
        project.getTraitSet().replace(BeamLogicalConvention.INSTANCE),
        convert(input, input.getTraitSet().replace(BeamLogicalConvention.INSTANCE)),
        project.getProjects(),
        project.getRowType());
  }
}
