/*
 * 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.indices.analysis;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.opensearch.Version;
import org.opensearch.common.settings.Settings;
import org.opensearch.core.xcontent.XContentBuilder;
import org.opensearch.test.OpenSearchIntegTestCase;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
import static org.opensearch.test.VersionUtils.randomVersion;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.notNullValue;

@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.SUITE)
public class PreBuiltAnalyzerIntegrationIT extends OpenSearchIntegTestCase {

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

    public void testThatPreBuiltAnalyzersAreNotClosedOnIndexClose() throws Exception {
        Map<PreBuiltAnalyzers, List<Version>> loadedAnalyzers = new HashMap<>();
        List<String> indexNames = new ArrayList<>();
        final int numIndices = scaledRandomIntBetween(2, 4);
        for (int i = 0; i < numIndices; i++) {
            String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
            indexNames.add(indexName);

            int randomInt = randomInt(PreBuiltAnalyzers.values().length - 1);
            PreBuiltAnalyzers preBuiltAnalyzer = PreBuiltAnalyzers.values()[randomInt];
            String name = preBuiltAnalyzer.name().toLowerCase(Locale.ROOT);

            Version randomVersion = randomVersion(random());
            if (!loadedAnalyzers.containsKey(preBuiltAnalyzer)) {
                loadedAnalyzers.put(preBuiltAnalyzer, new ArrayList<Version>());
            }
            loadedAnalyzers.get(preBuiltAnalyzer).add(randomVersion);

            final XContentBuilder mapping = jsonBuilder().startObject()
                .startObject("properties")
                .startObject("foo")
                .field("type", "text")
                .field("analyzer", name)
                .endObject()
                .endObject()
                .endObject();

            Settings versionSettings = settings(randomVersion).build();
            client().admin().indices().prepareCreate(indexName).setMapping(mapping).setSettings(versionSettings).get();
        }

        ensureGreen();

        final int numDocs = randomIntBetween(10, 100);
        // index some amount of data
        for (int i = 0; i < numDocs; i++) {
            String randomIndex = indexNames.get(randomInt(indexNames.size() - 1));
            String randomId = randomInt() + "";

            Map<String, Object> data = new HashMap<>();
            data.put("foo", randomAlphaOfLength(scaledRandomIntBetween(5, 50)));

            index(randomIndex, "type", randomId, data);
        }

        refresh();

        // close some of the indices
        int amountOfIndicesToClose = randomInt(numIndices - 1);
        for (int i = 0; i < amountOfIndicesToClose; i++) {
            String indexName = indexNames.get(i);
            client().admin().indices().prepareClose(indexName).execute().actionGet();
        }

        ensureGreen();

        // check that all above configured analyzers have been loaded
        assertThatAnalyzersHaveBeenLoaded(loadedAnalyzers);

        // check that all of the prebuilt analyzers are still open
        assertLuceneAnalyzersAreNotClosed(loadedAnalyzers);
    }

    private void assertThatAnalyzersHaveBeenLoaded(Map<PreBuiltAnalyzers, List<Version>> expectedLoadedAnalyzers) {
        for (Map.Entry<PreBuiltAnalyzers, List<Version>> entry : expectedLoadedAnalyzers.entrySet()) {
            for (Version version : entry.getValue()) {
                // if it is not null in the cache, it has been loaded
                assertThat(entry.getKey().getCache().get(version), is(notNullValue()));
            }
        }
    }

    // ensure analyzers are still open by checking there is no ACE
    private void assertLuceneAnalyzersAreNotClosed(Map<PreBuiltAnalyzers, List<Version>> loadedAnalyzers) throws IOException {
        for (Map.Entry<PreBuiltAnalyzers, List<Version>> preBuiltAnalyzerEntry : loadedAnalyzers.entrySet()) {
            for (Version version : preBuiltAnalyzerEntry.getValue()) {
                Analyzer analyzer = preBuiltAnalyzerEntry.getKey().getCache().get(version);
                try (TokenStream stream = analyzer.tokenStream("foo", "bar")) {
                    stream.reset();
                    while (stream.incrementToken()) {
                    }
                    stream.end();
                }
            }
        }
    }
}