/*
 * 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;

import org.apache.lucene.index.LeafReaderContext;
import org.opensearch.search.internal.SearchContext;

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

/**
 * An aggregator that is not collected, this can typically be used when running an aggregation over a field that doesn't have
 * a mapping.
 *
 * @opensearch.internal
 */
public abstract class NonCollectingAggregator extends AggregatorBase {
    /**
     * Build a {@linkplain NonCollectingAggregator} for any aggregator.
     */
    protected NonCollectingAggregator(
        String name,
        SearchContext context,
        Aggregator parent,
        AggregatorFactories subFactories,
        Map<String, Object> metadata
    ) throws IOException {
        super(name, subFactories, context, parent, CardinalityUpperBound.NONE, metadata);
    }

    @Override
    public final LeafBucketCollector getLeafCollector(LeafReaderContext reader, LeafBucketCollector sub) {
        // the framework will automatically eliminate it
        return LeafBucketCollector.NO_OP_COLLECTOR;
    }

    @Override
    public InternalAggregation[] buildAggregations(long[] owningBucketOrds) throws IOException {
        InternalAggregation[] results = new InternalAggregation[owningBucketOrds.length];
        for (int ordIdx = 0; ordIdx < owningBucketOrds.length; ordIdx++) {
            results[ordIdx] = buildEmptyAggregation();
        }
        return results;
    }
}
