/*
 * 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.search.aggregations.bucket.terms;

import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.search.aggregations.bucket.terms.heuristic.SignificanceHeuristic;
import org.elasticsearch.xcontent.XContentBuilder;

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

/**
 * Result of the running the significant terms aggregation on a String field.
 */
public class SignificantStringTerms extends InternalMappedSignificantTerms<SignificantStringTerms, SignificantStringTerms.Bucket> {
    public static final String NAME = "sigsterms";

    public static class Bucket extends InternalSignificantTerms.Bucket<Bucket> {

        BytesRef termBytes;

        public Bucket(
            BytesRef term,
            long subsetDf,
            long supersetDf,
            InternalAggregations aggregations,
            DocValueFormat format,
            double score
        ) {
            super(subsetDf, supersetDf, aggregations, format);
            this.termBytes = term;
            this.score = score;
        }

        /**
         * Read from a stream.
         */
        public Bucket(StreamInput in, DocValueFormat format) throws IOException {
            super(format);
            termBytes = in.readBytesRef();
            subsetDf = in.readVLong();
            supersetDf = in.readVLong();
            score = in.readDouble();
            aggregations = InternalAggregations.readFrom(in);
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {
            out.writeBytesRef(termBytes);
            out.writeVLong(subsetDf);
            out.writeVLong(supersetDf);
            out.writeDouble(getSignificanceScore());
            aggregations.writeTo(out);
        }

        @Override
        public String getKeyAsString() {
            return format.format(termBytes).toString();
        }

        @Override
        public String getKey() {
            return getKeyAsString();
        }

        @Override
        protected XContentBuilder keyToXContent(XContentBuilder builder) throws IOException {
            return builder.field(CommonFields.KEY.getPreferredName(), getKeyAsString());
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) return true;
            if (obj == null || getClass() != obj.getClass()) return false;
            if (super.equals(obj) == false) return false;

            return super.equals(obj) && Objects.equals(termBytes, ((SignificantStringTerms.Bucket) obj).termBytes);
        }

        @Override
        public int hashCode() {
            return Objects.hash(super.hashCode(), termBytes);
        }
    }

    public SignificantStringTerms(
        String name,
        int requiredSize,
        long minDocCount,
        Map<String, Object> metadata,
        DocValueFormat format,
        long subsetSize,
        long supersetSize,
        SignificanceHeuristic significanceHeuristic,
        List<Bucket> buckets
    ) {
        super(name, requiredSize, minDocCount, metadata, format, subsetSize, supersetSize, significanceHeuristic, buckets);
    }

    /**
     * Read from a stream.
     */
    public SignificantStringTerms(StreamInput in) throws IOException {
        super(in, Bucket::new);
    }

    @Override
    public String getWriteableName() {
        return NAME;
    }

    @Override
    public SignificantStringTerms create(List<SignificantStringTerms.Bucket> buckets) {
        return new SignificantStringTerms(
            name,
            requiredSize,
            minDocCount,
            metadata,
            format,
            subsetSize,
            supersetSize,
            significanceHeuristic,
            buckets
        );
    }

    @Override
    public Bucket createBucket(InternalAggregations aggregations, SignificantStringTerms.Bucket prototype) {
        return new Bucket(prototype.termBytes, prototype.subsetDf, prototype.supersetDf, aggregations, prototype.format, prototype.score);
    }

    @Override
    protected SignificantStringTerms create(long subsetSize, long supersetSize, List<Bucket> buckets) {
        return new SignificantStringTerms(
            getName(),
            requiredSize,
            minDocCount,
            getMetadata(),
            format,
            subsetSize,
            supersetSize,
            significanceHeuristic,
            buckets
        );
    }

    @Override
    protected Bucket[] createBucketsArray(int size) {
        return new Bucket[size];
    }

    @Override
    Bucket createBucket(long subsetDf, long supersetDf, InternalAggregations aggregations, SignificantStringTerms.Bucket prototype) {
        return new Bucket(prototype.termBytes, subsetDf, supersetDf, aggregations, format, prototype.score);
    }
}