/*
 * 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.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.core.Releasables;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.AggregationReduceContext;
import org.elasticsearch.search.aggregations.AggregatorReducer;
import org.elasticsearch.search.aggregations.BucketOrder;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.xcontent.XContentBuilder;

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

/**
 * Result of the {@link TermsAggregator} when the field is some kind of decimal number like a float, double, or distance.
 */
public class DoubleTerms extends InternalMappedTerms<DoubleTerms, DoubleTerms.Bucket> {
    public static final String NAME = "dterms";

    public static class Bucket extends InternalTerms.Bucket<Bucket> {
        double term;

        Bucket(
            double term,
            long docCount,
            InternalAggregations aggregations,
            boolean showDocCountError,
            long docCountError,
            DocValueFormat format
        ) {
            super(docCount, aggregations, showDocCountError, docCountError, format);
            this.term = term;
        }

        /**
         * Read from a stream.
         */
        Bucket(StreamInput in, DocValueFormat format, boolean showDocCountError) throws IOException {
            super(in, format, showDocCountError);
            term = in.readDouble();
        }

        @Override
        protected void writeTermTo(StreamOutput out) throws IOException {
            out.writeDouble(term);
        }

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

        @Override
        public Object getKey() {
            return term;
        }

        @Override
        public Number getKeyAsNumber() {
            return term;
        }

        @Override
        public int compareKey(Bucket other) {
            return Double.compare(term, other.term);
        }

        @Override
        protected final XContentBuilder keyToXContent(XContentBuilder builder) throws IOException {
            builder.field(CommonFields.KEY.getPreferredName(), term);
            if (format != DocValueFormat.RAW) {
                builder.field(CommonFields.KEY_AS_STRING.getPreferredName(), format.format(term).toString());
            }
            return builder;
        }

        @Override
        public boolean equals(Object obj) {
            return super.equals(obj) && Objects.equals(term, ((Bucket) obj).term);
        }

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

    public DoubleTerms(
        String name,
        BucketOrder reduceOrder,
        BucketOrder order,
        int requiredSize,
        long minDocCount,
        Map<String, Object> metadata,
        DocValueFormat format,
        int shardSize,
        boolean showTermDocCountError,
        long otherDocCount,
        List<Bucket> buckets,
        Long docCountError
    ) {
        super(
            name,
            reduceOrder,
            order,
            requiredSize,
            minDocCount,
            metadata,
            format,
            shardSize,
            showTermDocCountError,
            otherDocCount,
            buckets,
            docCountError
        );
    }

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

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

    @Override
    public DoubleTerms create(List<Bucket> buckets) {
        return new DoubleTerms(
            name,
            reduceOrder,
            order,
            requiredSize,
            minDocCount,
            metadata,
            format,
            shardSize,
            showTermDocCountError,
            otherDocCount,
            buckets,
            docCountError
        );
    }

    @Override
    public Bucket createBucket(InternalAggregations aggregations, Bucket prototype) {
        return new Bucket(
            prototype.term,
            prototype.docCount,
            aggregations,
            showTermDocCountError,
            prototype.getDocCountError(),
            prototype.format
        );
    }

    @Override
    protected DoubleTerms create(String name, List<Bucket> buckets, BucketOrder reduceOrder, long docCountError, long otherDocCount) {
        return new DoubleTerms(
            name,
            reduceOrder,
            order,
            requiredSize,
            minDocCount,
            getMetadata(),
            format,
            shardSize,
            showTermDocCountError,
            otherDocCount,
            buckets,
            docCountError
        );
    }

    @Override
    protected AggregatorReducer getLeaderReducer(AggregationReduceContext reduceContext, int size) {
        return new AggregatorReducer() {
            private final AggregatorReducer processor = termsAggregationReducer(reduceContext, size);

            @Override
            public void accept(InternalAggregation aggregation) {
                if (aggregation instanceof LongTerms longTerms) {
                    processor.accept(LongTerms.convertLongTermsToDouble(longTerms, format));
                } else {
                    processor.accept(aggregation);
                }
            }

            @Override
            public InternalAggregation get() {
                return processor.get();
            }

            @Override
            public void close() {
                Releasables.close(processor);
            }
        };
    }

    @Override
    protected Bucket createBucket(long docCount, InternalAggregations aggs, long docCountError, DoubleTerms.Bucket prototype) {
        return new Bucket(prototype.term, docCount, aggs, showTermDocCountError, docCountError, format);
    }
}