/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.planner.projection;

import com.google.common.collect.ImmutableList;
import io.crate.analyze.symbol.Symbol;
import io.crate.analyze.symbol.Value;
import io.crate.metadata.RowGranularity;
import io.crate.types.DataTypes;
import org.elasticsearch.common.io.stream.StreamOutput;

import java.io.IOException;
import java.util.List;
import java.util.function.Function;

public class MergeCountProjection extends Projection {

    public static final MergeCountProjection INSTANCE = new MergeCountProjection();

    private final static List<Symbol> OUTPUTS = ImmutableList.<Symbol>of(
        new Value(DataTypes.LONG)  // number of rows updated
    );

    private MergeCountProjection() {
    }

    @Override
    public List<? extends Symbol> outputs() {
        return OUTPUTS;
    }

    @Override
    public boolean equals(Object o) {
        return this == o;
    }


    @Override
    public void writeTo(StreamOutput out) throws IOException {
    }

    @Override
    public RowGranularity requiredGranularity() {
        return RowGranularity.CLUSTER;
    }

    @Override
    public void replaceSymbols(Function<Symbol, Symbol> replaceFunction) {
    }

    @Override
    public ProjectionType projectionType() {
        return ProjectionType.MERGE_COUNT_AGGREGATION;
    }

    @Override
    public <C, R> R accept(ProjectionVisitor<C, R> visitor, C context) {
        return visitor.visitMergeCountProjection(this, context);
    }
}