/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */
package org.elasticsearch.join.aggregations;

import org.apache.lucene.search.Query;
import org.elasticsearch.common.util.LongArray;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.AggregatorFactories;
import org.elasticsearch.search.aggregations.CardinalityUpperBound;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.support.AggregationContext;
import org.elasticsearch.search.aggregations.support.ValuesSource;
import org.elasticsearch.xcontent.ParseField;

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

public class ParentToChildrenAggregator extends ParentJoinAggregator {

    static final ParseField TYPE_FIELD = new ParseField("type");

    public ParentToChildrenAggregator(
        String name,
        AggregatorFactories factories,
        AggregationContext context,
        Aggregator parent,
        Query childFilter,
        Query parentFilter,
        ValuesSource.Bytes.WithOrdinals valuesSource,
        long maxOrd,
        CardinalityUpperBound cardinality,
        Map<String, Object> metadata
    ) throws IOException {
        super(name, factories, context, parent, parentFilter, childFilter, valuesSource, maxOrd, cardinality, metadata);
    }

    @Override
    public InternalAggregation[] buildAggregations(LongArray owningBucketOrds) throws IOException {
        return buildAggregationsForSingleBucket(
            owningBucketOrds,
            (owningBucketOrd, subAggregationResults) -> new InternalChildren(
                name,
                bucketDocCount(owningBucketOrd),
                subAggregationResults,
                metadata()
            )
        );
    }

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