/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * 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.
 */
/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.search.aggregations.metrics;

import org.opensearch.action.search.SearchResponse;
import org.opensearch.common.settings.Settings;
import org.opensearch.plugins.Plugin;
import org.opensearch.script.Script;
import org.opensearch.script.ScriptType;
import org.opensearch.search.aggregations.BucketOrder;
import org.opensearch.search.aggregations.InternalAggregation;
import org.opensearch.search.aggregations.bucket.filter.Filter;
import org.opensearch.search.aggregations.bucket.global.Global;
import org.opensearch.search.aggregations.bucket.terms.Terms;
import org.opensearch.test.OpenSearchIntegTestCase;

import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
import static org.opensearch.index.query.QueryBuilders.termQuery;
import static org.opensearch.search.aggregations.AggregationBuilders.count;
import static org.opensearch.search.aggregations.AggregationBuilders.filter;
import static org.opensearch.search.aggregations.AggregationBuilders.global;
import static org.opensearch.search.aggregations.AggregationBuilders.terms;
import static org.opensearch.search.aggregations.metrics.MetricAggScriptPlugin.METRIC_SCRIPT_ENGINE;
import static org.opensearch.search.aggregations.metrics.MetricAggScriptPlugin.RANDOM_SCRIPT;
import static org.opensearch.search.aggregations.metrics.MetricAggScriptPlugin.SUM_FIELD_PARAMS_SCRIPT;
import static org.opensearch.search.aggregations.metrics.MetricAggScriptPlugin.SUM_VALUES_FIELD_SCRIPT;
import static org.opensearch.search.aggregations.metrics.MetricAggScriptPlugin.VALUE_FIELD_SCRIPT;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.notNullValue;

@OpenSearchIntegTestCase.SuiteScopeTestCase
public class ValueCountIT extends OpenSearchIntegTestCase {
    @Override
    public void setupSuiteScopeCluster() throws Exception {
        createIndex("idx");
        createIndex("idx_unmapped");
        for (int i = 0; i < 10; i++) {
            client().prepareIndex("idx")
                .setId("" + i)
                .setSource(
                    jsonBuilder().startObject().field("value", i + 1).startArray("values").value(i + 2).value(i + 3).endArray().endObject()
                )
                .get();
        }
        client().admin().indices().prepareFlush().get();
        client().admin().indices().prepareRefresh().get();
        ensureSearchable();
    }

    @Override
    protected Collection<Class<? extends Plugin>> nodePlugins() {
        return Collections.singletonList(MetricAggScriptPlugin.class);
    }

    public void testUnmapped() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx_unmapped")
            .setQuery(matchAllQuery())
            .addAggregation(count("count").field("value"))
            .get();

        assertThat(searchResponse.getHits().getTotalHits().value, equalTo(0L));

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(0L));
    }

    public void testSingleValuedField() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(count("count").field("value"))
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(10L));
    }

    public void testSingleValuedFieldGetProperty() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(global("global").subAggregation(count("count").field("value")))
            .get();

        assertHitCount(searchResponse, 10);

        Global global = searchResponse.getAggregations().get("global");
        assertThat(global, notNullValue());
        assertThat(global.getName(), equalTo("global"));
        assertThat(global.getDocCount(), equalTo(10L));
        assertThat(global.getAggregations(), notNullValue());
        assertThat(global.getAggregations().asMap().size(), equalTo(1));

        ValueCount valueCount = global.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(10L));
        assertThat((ValueCount) ((InternalAggregation) global).getProperty("count"), equalTo(valueCount));
        assertThat((double) ((InternalAggregation) global).getProperty("count.value"), equalTo(10d));
        assertThat((double) ((InternalAggregation) valueCount).getProperty("value"), equalTo(10d));
    }

    public void testSingleValuedFieldPartiallyUnmapped() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx", "idx_unmapped")
            .setQuery(matchAllQuery())
            .addAggregation(count("count").field("value"))
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(10L));
    }

    public void testMultiValuedField() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(count("count").field("values"))
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(20L));
    }

    public void testSingleValuedScript() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(
                count("count").script(new Script(ScriptType.INLINE, METRIC_SCRIPT_ENGINE, VALUE_FIELD_SCRIPT, Collections.emptyMap()))
            )
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(10L));
    }

    public void testMultiValuedScript() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(
                count("count").script(new Script(ScriptType.INLINE, METRIC_SCRIPT_ENGINE, SUM_VALUES_FIELD_SCRIPT, Collections.emptyMap()))
            )
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(20L));
    }

    public void testSingleValuedScriptWithParams() throws Exception {
        Map<String, Object> params = Collections.singletonMap("field", "value");
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(count("count").script(new Script(ScriptType.INLINE, METRIC_SCRIPT_ENGINE, SUM_FIELD_PARAMS_SCRIPT, params)))
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(10L));
    }

    public void testMultiValuedScriptWithParams() throws Exception {
        Map<String, Object> params = Collections.singletonMap("field", "values");
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(count("count").script(new Script(ScriptType.INLINE, METRIC_SCRIPT_ENGINE, SUM_FIELD_PARAMS_SCRIPT, params)))
            .get();

        assertHitCount(searchResponse, 10);

        ValueCount valueCount = searchResponse.getAggregations().get("count");
        assertThat(valueCount, notNullValue());
        assertThat(valueCount.getName(), equalTo("count"));
        assertThat(valueCount.getValue(), equalTo(20L));
    }

    /**
     * Make sure that a request using a deterministic script or not using a script get cached.
     * Ensure requests using nondeterministic scripts do not get cached.
     */
    public void testScriptCaching() throws Exception {
        assertAcked(
            prepareCreate("cache_test_idx").setMapping("d", "type=long")
                .setSettings(Settings.builder().put("requests.cache.enable", true).put("number_of_shards", 1).put("number_of_replicas", 1))
                .get()
        );
        indexRandom(
            true,
            client().prepareIndex("cache_test_idx").setId("1").setSource("s", 1),
            client().prepareIndex("cache_test_idx").setId("2").setSource("s", 2)
        );

        // Make sure we are starting with a clear cache
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(0L)
        );

        // Test that a request using a nondeterministic script does not get cached
        SearchResponse r = client().prepareSearch("cache_test_idx")
            .setSize(0)
            .addAggregation(
                count("foo").field("d").script(new Script(ScriptType.INLINE, METRIC_SCRIPT_ENGINE, RANDOM_SCRIPT, Collections.emptyMap()))
            )
            .get();
        assertSearchResponse(r);

        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(0L)
        );

        // Test that a request using a deterministic script gets cached
        r = client().prepareSearch("cache_test_idx")
            .setSize(0)
            .addAggregation(
                count("foo").field("d")
                    .script(new Script(ScriptType.INLINE, METRIC_SCRIPT_ENGINE, VALUE_FIELD_SCRIPT, Collections.emptyMap()))
            )
            .get();
        assertSearchResponse(r);

        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(1L)
        );

        // Ensure that non-scripted requests are cached as normal
        r = client().prepareSearch("cache_test_idx").setSize(0).addAggregation(count("foo").field("d")).get();
        assertSearchResponse(r);

        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(2L)
        );
    }

    public void testOrderByEmptyAggregation() throws Exception {
        SearchResponse searchResponse = client().prepareSearch("idx")
            .setQuery(matchAllQuery())
            .addAggregation(
                terms("terms").field("value")
                    .order(BucketOrder.compound(BucketOrder.aggregation("filter>count", true)))
                    .subAggregation(filter("filter", termQuery("value", 100)).subAggregation(count("count").field("value")))
            )
            .get();

        assertHitCount(searchResponse, 10);

        Terms terms = searchResponse.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        List<? extends Terms.Bucket> buckets = terms.getBuckets();
        assertThat(buckets, notNullValue());
        assertThat(buckets.size(), equalTo(10));

        for (int i = 0; i < 10; i++) {
            Terms.Bucket bucket = buckets.get(i);
            assertThat(bucket, notNullValue());
            assertThat(bucket.getKeyAsNumber(), equalTo((long) i + 1));
            assertThat(bucket.getDocCount(), equalTo(1L));
            Filter filter = bucket.getAggregations().get("filter");
            assertThat(filter, notNullValue());
            assertThat(filter.getDocCount(), equalTo(0L));
            ValueCount count = filter.getAggregations().get("count");
            assertThat(count, notNullValue());
            assertThat(count.value(), equalTo(0.0));

        }
    }
}