/*
 * 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.join.aggregations;

import org.apache.lucene.search.Query;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.AggregatorFactories;
import org.elasticsearch.search.aggregations.AggregatorFactory;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.NonCollectingAggregator;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.aggregations.support.ValuesSource;
import org.elasticsearch.search.aggregations.support.ValuesSource.Bytes.ParentChild;
import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
import org.elasticsearch.search.aggregations.support.ValuesSourceConfig;
import org.elasticsearch.search.internal.SearchContext;

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

public class ChildrenAggregatorFactory
        extends ValuesSourceAggregatorFactory<ValuesSource.Bytes.WithOrdinals.ParentChild, ChildrenAggregatorFactory> {

    private final String parentType;
    private final Query parentFilter;
    private final Query childFilter;

    public ChildrenAggregatorFactory(String name, ValuesSourceConfig<ParentChild> config, String parentType, Query childFilter,
            Query parentFilter, SearchContext context, AggregatorFactory<?> parent, AggregatorFactories.Builder subFactoriesBuilder,
            Map<String, Object> metaData) throws IOException {
        super(name, config, context, parent, subFactoriesBuilder, metaData);
        this.parentType = parentType;
        this.childFilter = childFilter;
        this.parentFilter = parentFilter;
    }

    @Override
    protected Aggregator createUnmapped(Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
            throws IOException {
        return new NonCollectingAggregator(name, context, parent, pipelineAggregators, metaData) {

            @Override
            public InternalAggregation buildEmptyAggregation() {
                return new InternalChildren(name, 0, buildEmptySubAggregations(), pipelineAggregators(), metaData());
            }

        };
    }

    @Override
    protected Aggregator doCreateInternal(ValuesSource.Bytes.WithOrdinals.ParentChild valuesSource, Aggregator parent,
            boolean collectsFromSingleBucket, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData)
                    throws IOException {
        long maxOrd = valuesSource.globalMaxOrd(context.searcher(), parentType);
        return new ParentToChildrenAggregator(name, factories, context, parent, parentType, childFilter, parentFilter, valuesSource, maxOrd,
                pipelineAggregators, metaData);
    }

}