/*
 * 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.index.search.child;

import com.carrotsearch.hppc.FloatArrayList;

import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.util.BytesRef;

import java.io.IOException;

class MockScorer extends Scorer {

    final ScoreType scoreType;
    FloatArrayList scores;

    MockScorer(ScoreType scoreType) {
        super(null);
        this.scoreType = scoreType;
    }

    @Override
    public float score() throws IOException {
        if (scoreType == ScoreType.NONE) {
            return 1.0f;
        }
        float aggregateScore = 0;

        // in the case of a min value, it can't start at 0 (the lowest score); in all cases, it doesn't hurt to use the
        //  first score, so we can safely use the first value by skipping it in the loop
        if (scores.elementsCount != 0) {
            aggregateScore = scores.buffer[0];

            for (int i = 1; i < scores.elementsCount; i++) {
                float score = scores.buffer[i];
                switch (scoreType) {
                    case MIN:
                        if (aggregateScore > score) {
                            aggregateScore = score;
                        }
                        break;
                    case MAX:
                        if (aggregateScore < score) {
                            aggregateScore = score;
                        }
                        break;
                    case SUM:
                    case AVG:
                        aggregateScore += score;
                        break;
                }
            }

            if (scoreType == ScoreType.AVG) {
                aggregateScore /= scores.elementsCount;
            }
        }

        return aggregateScore;
    }

    @Override
    public int freq() throws IOException {
        return 0;
    }

    @Override
    public int docID() {
        return 0;
    }

    @Override
    public DocIdSetIterator iterator() {
        throw new UnsupportedOperationException();
    }
}