/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.
 */
/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.search.aggregations.bucket.sampler;

import org.opensearch.core.common.io.stream.StreamInput;
import org.opensearch.core.xcontent.XContentBuilder;
import org.opensearch.search.aggregations.Aggregation;
import org.opensearch.search.aggregations.InternalAggregation;
import org.opensearch.search.aggregations.InternalAggregations;

import java.io.IOException;
import java.util.List;
import java.util.Map;

/**
 * Implementation of an unmapped sampler
 *
 * @opensearch.internal
 */
public class UnmappedSampler extends InternalSampler {
    public static final String NAME = "unmapped_sampler";

    UnmappedSampler(String name, Map<String, Object> metadata) {
        super(name, 0, InternalAggregations.EMPTY, metadata);
    }

    /**
     * Read from a stream.
     */
    public UnmappedSampler(StreamInput in) throws IOException {
        super(in);
    }

    @Override
    public String getWriteableName() {
        return NAME;
    }

    @Override
    public InternalAggregation reduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
        return new UnmappedSampler(name, metadata);
    }

    @Override
    public boolean isMapped() {
        return false;
    }

    @Override
    public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
        builder.field(Aggregation.CommonFields.DOC_COUNT.getPreferredName(), 0);
        return builder;
    }

}
