/*
 * 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.
 */
package org.elasticsearch.search.aggregations.bucket.sampler;

import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.search.aggregations.AggregationStreams;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;

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

/**
 *
 */
public class UnmappedSampler extends InternalSampler {

    public static final Type TYPE = new Type("sampler", "umsampler");


    public static final AggregationStreams.Stream STREAM = new AggregationStreams.Stream() {
        @Override
        public UnmappedSampler readResult(StreamInput in) throws IOException {
            UnmappedSampler sampler = new UnmappedSampler();
            sampler.readFrom(in);
            return sampler;
        }
    };

    public static void registerStreams() {
        AggregationStreams.registerStream(STREAM, TYPE.stream());
    }

    UnmappedSampler() {
    }

    public UnmappedSampler(String name, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) {
        super(name, 0, InternalAggregations.EMPTY, pipelineAggregators, metaData);
    }

    @Override
    public Type type() {
        return TYPE;
    }

    @Override
    public InternalAggregation doReduce(List<InternalAggregation> aggregations, ReduceContext reduceContext) {
        for (InternalAggregation agg : aggregations) {
            if (!(agg instanceof UnmappedSampler)) {
                return agg.reduce(aggregations, reduceContext);
            }
        }
        return this;
    }

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

}