/*
 * 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.search.aggregations.bucket.significant;

import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.InternalAggregations;
import org.elasticsearch.search.aggregations.bucket.significant.heuristics.SignificanceHeuristic;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;

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 subsetSize, long supersetDf, long supersetSize, InternalAggregations aggregations,
                DocValueFormat format) {
            super(subsetDf, subsetSize, supersetDf, supersetSize, aggregations, format);
            this.termBytes = term;
        }

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

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

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

        @Override
        public Number getKeyAsNumber() {
            // this method is needed for scripted numeric aggregations
            return Double.parseDouble(termBytes.utf8ToString());
        }

        @Override
        int compareTerm(SignificantTerms.Bucket other) {
            return termBytes.compareTo(((Bucket) other).termBytes);
        }

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

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

        @Override
        Bucket newBucket(long subsetDf, long subsetSize, long supersetDf, long supersetSize, InternalAggregations aggregations) {
            return new Bucket(termBytes, subsetDf, subsetSize, supersetDf, supersetSize, aggregations, format);
        }

        @Override
        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
            builder.startObject();
            builder.field(CommonFields.KEY.getPreferredName(), getKeyAsString());
            builder.field(CommonFields.DOC_COUNT.getPreferredName(), getDocCount());
            builder.field("score", score);
            builder.field("bg_count", supersetDf);
            aggregations.toXContentInternal(builder, params);
            builder.endObject();
            return builder;
        }

        @Override
        public boolean equals(Object obj) {
            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, List<PipelineAggregator> pipelineAggregators,
            Map<String, Object> metaData, DocValueFormat format, long subsetSize, long supersetSize,
            SignificanceHeuristic significanceHeuristic, List<Bucket> buckets) {
        super(name, requiredSize, minDocCount, pipelineAggregators, 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, pipelineAggregators(), metaData, format, subsetSize,
                supersetSize, significanceHeuristic, buckets);
    }

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

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

    @Override
    public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
        builder.field("doc_count", subsetSize);
        builder.startArray(CommonFields.BUCKETS.getPreferredName());
        for (Bucket bucket : buckets) {
            //There is a condition (presumably when only one shard has a bucket?) where reduce is not called
            // and I end up with buckets that contravene the user's min_doc_count criteria in my reducer
            if (bucket.subsetDf >= minDocCount) {
                bucket.toXContent(builder, params);
            }
        }
        builder.endArray();
        return builder;
    }

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