/*
 * 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;

import org.elasticsearch.action.index.IndexRequestBuilder;
import org.elasticsearch.cluster.metadata.IndexMetadata;
import org.elasticsearch.common.geo.GeoPoint;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.IndexVersion;
import org.elasticsearch.index.query.GeoBoundingBoxQueryBuilder;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.bucket.geogrid.GeoGrid;
import org.elasticsearch.search.aggregations.bucket.geogrid.GeoGrid.Bucket;
import org.elasticsearch.test.ESIntegTestCase;
import org.elasticsearch.test.index.IndexVersionUtils;
import org.elasticsearch.xcontent.XContentBuilder;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;

import static org.elasticsearch.geometry.utils.Geohash.PRECISION;
import static org.elasticsearch.geometry.utils.Geohash.stringEncode;
import static org.elasticsearch.search.aggregations.AggregationBuilders.geohashGrid;
import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertNoFailuresAndResponse;
import static org.elasticsearch.xcontent.XContentFactory.jsonBuilder;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.equalTo;

@ESIntegTestCase.SuiteScopeTestCase
public class GeoHashGridIT extends ESIntegTestCase {

    @Override
    protected boolean forbidPrivateIndexSettings() {
        return false;
    }

    private final IndexVersion version = IndexVersionUtils.randomCompatibleWriteVersion(random());

    static Map<String, Integer> expectedDocCountsForGeoHash = null;
    static Map<String, Integer> multiValuedExpectedDocCountsForGeoHash = null;
    static int numDocs = 100;

    static String smallestGeoHash = null;

    private static IndexRequestBuilder indexCity(String index, String name, List<String> latLon) throws Exception {
        XContentBuilder source = jsonBuilder().startObject().field("city", name);
        if (latLon != null) {
            source = source.field("location", latLon);
        }
        source = source.endObject();
        return prepareIndex(index).setSource(source);
    }

    private static IndexRequestBuilder indexCity(String index, String name, String latLon) throws Exception {
        return indexCity(index, name, Arrays.<String>asList(latLon));
    }

    @Override
    public void setupSuiteScopeCluster() throws Exception {
        createIndex("idx_unmapped");

        Settings settings = Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, version).build();

        assertAcked(prepareCreate("idx").setSettings(settings).setMapping("location", "type=geo_point", "city", "type=keyword"));

        List<IndexRequestBuilder> cities = new ArrayList<>();
        Random random = random();
        expectedDocCountsForGeoHash = new HashMap<>(numDocs * 2);
        for (int i = 0; i < numDocs; i++) {
            // generate random point
            double lat = (180d * random.nextDouble()) - 90d;
            double lng = (360d * random.nextDouble()) - 180d;
            String randomGeoHash = stringEncode(lng, lat, PRECISION);
            // Index at the highest resolution
            cities.add(indexCity("idx", randomGeoHash, lat + ", " + lng));
            expectedDocCountsForGeoHash.put(randomGeoHash, expectedDocCountsForGeoHash.getOrDefault(randomGeoHash, 0) + 1);
            // Update expected doc counts for all resolutions..
            for (int precision = PRECISION - 1; precision > 0; precision--) {
                String hash = stringEncode(lng, lat, precision);
                if ((smallestGeoHash == null) || (hash.length() < smallestGeoHash.length())) {
                    smallestGeoHash = hash;
                }
                expectedDocCountsForGeoHash.put(hash, expectedDocCountsForGeoHash.getOrDefault(hash, 0) + 1);
            }
        }
        indexRandom(true, cities);

        assertAcked(
            prepareCreate("multi_valued_idx").setSettings(settings).setMapping("location", "type=geo_point", "city", "type=keyword")
        );

        cities = new ArrayList<>();
        multiValuedExpectedDocCountsForGeoHash = new HashMap<>(numDocs * 2);
        for (int i = 0; i < numDocs; i++) {
            final int numPoints = random.nextInt(4);
            List<String> points = new ArrayList<>();
            Set<String> geoHashes = new HashSet<>();
            for (int j = 0; j < numPoints; ++j) {
                double lat = (180d * random.nextDouble()) - 90d;
                double lng = (360d * random.nextDouble()) - 180d;
                points.add(lat + "," + lng);
                // Update expected doc counts for all resolutions..
                for (int precision = PRECISION; precision > 0; precision--) {
                    final String geoHash = stringEncode(lng, lat, precision);
                    geoHashes.add(geoHash);
                }
            }
            cities.add(indexCity("multi_valued_idx", Integer.toString(i), points));
            for (String hash : geoHashes) {
                multiValuedExpectedDocCountsForGeoHash.put(hash, multiValuedExpectedDocCountsForGeoHash.getOrDefault(hash, 0) + 1);
            }
        }
        indexRandom(true, cities);

        ensureSearchable();
    }

    public void testSimple() throws Exception {
        for (int precision = 1; precision <= PRECISION; precision++) {
            final int finalPrecision = precision;
            assertNoFailuresAndResponse(
                prepareSearch("idx").addAggregation(geohashGrid("geohashgrid").field("location").precision(precision)),
                response -> {
                    GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
                    List<? extends Bucket> buckets = geoGrid.getBuckets();
                    Object[] propertiesKeys = (Object[]) ((InternalAggregation) geoGrid).getProperty("_key");
                    Object[] propertiesDocCounts = (Object[]) ((InternalAggregation) geoGrid).getProperty("_count");
                    for (int i = 0; i < buckets.size(); i++) {
                        GeoGrid.Bucket cell = buckets.get(i);
                        String geohash = cell.getKeyAsString();

                        long bucketCount = cell.getDocCount();
                        int expectedBucketCount = expectedDocCountsForGeoHash.get(geohash);
                        assertNotSame(bucketCount, 0);
                        assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
                        GeoPoint geoPoint = (GeoPoint) propertiesKeys[i];
                        assertThat(stringEncode(geoPoint.lon(), geoPoint.lat(), finalPrecision), equalTo(geohash));
                        assertThat((long) propertiesDocCounts[i], equalTo(bucketCount));
                    }
                }
            );
        }
    }

    public void testMultivalued() throws Exception {
        for (int precision = 1; precision <= PRECISION; precision++) {
            assertNoFailuresAndResponse(
                prepareSearch("multi_valued_idx").addAggregation(geohashGrid("geohashgrid").field("location").precision(precision)),
                response -> {
                    GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
                    for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
                        String geohash = cell.getKeyAsString();

                        long bucketCount = cell.getDocCount();
                        int expectedBucketCount = multiValuedExpectedDocCountsForGeoHash.get(geohash);
                        assertNotSame(bucketCount, 0);
                        assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
                    }
                }
            );
        }
    }

    public void testFiltered() throws Exception {
        GeoBoundingBoxQueryBuilder bbox = new GeoBoundingBoxQueryBuilder("location");
        bbox.setCorners(smallestGeoHash).queryName("bbox");
        for (int precision = 1; precision <= PRECISION; precision++) {
            assertNoFailuresAndResponse(
                prepareSearch("idx").addAggregation(
                    AggregationBuilders.filter("filtered", bbox)
                        .subAggregation(geohashGrid("geohashgrid").field("location").precision(precision))
                ),
                response -> {
                    SingleBucketAggregation filter = response.getAggregations().get("filtered");

                    GeoGrid geoGrid = filter.getAggregations().get("geohashgrid");
                    for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
                        String geohash = cell.getKeyAsString();
                        long bucketCount = cell.getDocCount();
                        int expectedBucketCount = expectedDocCountsForGeoHash.get(geohash);
                        assertNotSame(bucketCount, 0);
                        assertTrue("Buckets must be filtered", geohash.startsWith(smallestGeoHash));
                        assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
                    }
                }
            );
        }
    }

    public void testUnmapped() throws Exception {
        for (int precision = 1; precision <= PRECISION; precision++) {
            assertNoFailuresAndResponse(
                prepareSearch("idx_unmapped").addAggregation(geohashGrid("geohashgrid").field("location").precision(precision)),
                response -> {
                    GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
                    assertThat(geoGrid.getBuckets().size(), equalTo(0));
                }
            );
        }

    }

    public void testPartiallyUnmapped() throws Exception {
        for (int precision = 1; precision <= PRECISION; precision++) {
            assertNoFailuresAndResponse(
                prepareSearch("idx", "idx_unmapped").addAggregation(geohashGrid("geohashgrid").field("location").precision(precision)),
                response -> {
                    GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
                    for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
                        String geohash = cell.getKeyAsString();

                        long bucketCount = cell.getDocCount();
                        int expectedBucketCount = expectedDocCountsForGeoHash.get(geohash);
                        assertNotSame(bucketCount, 0);
                        assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
                    }
                }
            );
        }
    }

    public void testTopMatch() throws Exception {
        for (int precision = 1; precision <= PRECISION; precision++) {
            final int finalPrecision = precision;
            assertNoFailuresAndResponse(
                prepareSearch("idx").addAggregation(
                    geohashGrid("geohashgrid").field("location").size(1).shardSize(100).precision(precision)
                ),
                response -> {
                    GeoGrid geoGrid = response.getAggregations().get("geohashgrid");
                    // Check we only have one bucket with the best match for that resolution
                    assertThat(geoGrid.getBuckets().size(), equalTo(1));
                    for (GeoGrid.Bucket cell : geoGrid.getBuckets()) {
                        String geohash = cell.getKeyAsString();
                        long bucketCount = cell.getDocCount();
                        int expectedBucketCount = 0;
                        for (var entry : expectedDocCountsForGeoHash.entrySet()) {
                            if (entry.getKey().length() == finalPrecision) {
                                expectedBucketCount = Math.max(expectedBucketCount, entry.getValue());
                            }
                        }
                        assertNotSame(bucketCount, 0);
                        assertEquals("Geohash " + geohash + " has wrong doc count ", expectedBucketCount, bucketCount);
                    }
                }
            );
        }
    }

    public void testSizeIsZero() {
        final int size = 0;
        final int shardSize = 10000;
        IllegalArgumentException exception = expectThrows(
            IllegalArgumentException.class,
            () -> prepareSearch("idx").addAggregation(geohashGrid("geohashgrid").field("location").size(size).shardSize(shardSize)).get()
        );
        assertThat(exception.getMessage(), containsString("[size] must be greater than 0. Found [0] in [geohashgrid]"));
    }

    public void testShardSizeIsZero() {
        final int size = 100;
        final int shardSize = 0;
        IllegalArgumentException exception = expectThrows(
            IllegalArgumentException.class,
            () -> prepareSearch("idx").addAggregation(geohashGrid("geohashgrid").field("location").size(size).shardSize(shardSize)).get()
        );
        assertThat(exception.getMessage(), containsString("[shardSize] must be greater than 0. Found [0] in [geohashgrid]"));
    }

}