/*
 * 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; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */
package org.elasticsearch.xpack.analytics.aggregations.metrics;

import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.store.Directory;
import org.apache.lucene.tests.index.RandomIndexWriter;
import org.elasticsearch.index.mapper.MappedFieldType;
import org.elasticsearch.plugins.SearchPlugin;
import org.elasticsearch.search.aggregations.AggregationBuilder;
import org.elasticsearch.search.aggregations.AggregatorTestCase;
import org.elasticsearch.search.aggregations.metrics.InternalTDigestPercentileRanks;
import org.elasticsearch.search.aggregations.metrics.Percentile;
import org.elasticsearch.search.aggregations.metrics.PercentileRanks;
import org.elasticsearch.search.aggregations.metrics.PercentileRanksAggregationBuilder;
import org.elasticsearch.search.aggregations.metrics.PercentilesConfig;
import org.elasticsearch.search.aggregations.metrics.PercentilesMethod;
import org.elasticsearch.search.aggregations.metrics.TDigestExecutionHint;
import org.elasticsearch.search.aggregations.support.AggregationInspectionHelper;
import org.elasticsearch.search.aggregations.support.CoreValuesSourceType;
import org.elasticsearch.search.aggregations.support.ValuesSourceType;
import org.elasticsearch.xpack.analytics.AnalyticsPlugin;
import org.elasticsearch.xpack.analytics.aggregations.support.AnalyticsValuesSourceType;
import org.elasticsearch.xpack.analytics.mapper.HistogramFieldMapper;
import org.hamcrest.Matchers;

import java.io.IOException;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import static org.elasticsearch.xpack.analytics.AnalyticsTestsUtils.histogramFieldDocValues;

public class TDigestPreAggregatedPercentileRanksAggregatorTests extends AggregatorTestCase {

    @Override
    protected List<SearchPlugin> getSearchPlugins() {
        return List.of(new AnalyticsPlugin());
    }

    @Override
    protected AggregationBuilder createAggBuilderForTypeTest(MappedFieldType fieldType, String fieldName) {
        var tdigestConfig = new PercentilesConfig.TDigest();
        if (randomBoolean()) {
            tdigestConfig.setCompression(randomDoubleBetween(50, 200, true));
        }
        if (randomBoolean()) {
            tdigestConfig.parseExecutionHint(randomFrom(TDigestExecutionHint.values()).toString());
        }
        return new PercentileRanksAggregationBuilder("tdigest_percentiles", new double[] { 1.0 }).field(fieldName)
            .percentilesConfig(tdigestConfig);
    }

    @Override
    protected List<ValuesSourceType> getSupportedValuesSourceTypes() {
        // Note: this is the same list as Core, plus Analytics
        return List.of(
            CoreValuesSourceType.NUMERIC,
            CoreValuesSourceType.DATE,
            CoreValuesSourceType.BOOLEAN,
            AnalyticsValuesSourceType.HISTOGRAM
        );
    }

    public void testSimple() throws IOException {
        try (Directory dir = newDirectory(); RandomIndexWriter w = new RandomIndexWriter(random(), dir)) {
            Document doc = new Document();
            doc.add(histogramFieldDocValues("field", new double[] { 3, 0.2, 10 }));
            w.addDocument(doc);

            PercentileRanksAggregationBuilder aggBuilder = new PercentileRanksAggregationBuilder("my_agg", new double[] { 0.1, 0.5, 12 })
                .field("field")
                .method(PercentilesMethod.TDIGEST);
            MappedFieldType fieldType = new HistogramFieldMapper.HistogramFieldType("field", Collections.emptyMap());
            try (IndexReader reader = w.getReader()) {
                IndexSearcher searcher = new IndexSearcher(reader);
                PercentileRanks ranks = searchAndReduce(searcher, new AggTestConfig(aggBuilder, fieldType));
                Iterator<Percentile> rankIterator = ranks.iterator();
                Percentile rank = rankIterator.next();
                assertEquals(0.1, rank.getValue(), 0d);
                // TODO: Fix T-Digest: this assertion should pass but we currently get ~15
                // https://github.com/elastic/elasticsearch/issues/14851
                // assertThat(rank.getPercent(), Matchers.equalTo(0d));
                rank = rankIterator.next();
                assertEquals(0.5, rank.getValue(), 0d);
                assertThat(rank.getPercent(), Matchers.greaterThan(0d));
                assertThat(rank.getPercent(), Matchers.lessThan(100d));
                rank = rankIterator.next();
                assertEquals(12, rank.getValue(), 0d);
                // TODO: Fix T-Digest: this assertion should pass but we currently get ~59
                // https://github.com/elastic/elasticsearch/issues/14851
                // assertThat(rank.getPercent(), Matchers.equalTo(100d));
                assertFalse(rankIterator.hasNext());
                assertTrue(AggregationInspectionHelper.hasValue(((InternalTDigestPercentileRanks) ranks)));
            }
        }
    }
}
