/*
 * 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 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 or the Server
 * Side Public License, v 1.
 */

package org.elasticsearch.cluster.metadata;

import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.admin.indices.mapping.put.PutMappingClusterStateUpdateRequest;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.cluster.service.ClusterStateTaskExecutorUtils;
import org.elasticsearch.common.compress.CompressedXContent;
import org.elasticsearch.index.Index;
import org.elasticsearch.index.IndexService;
import org.elasticsearch.plugins.Plugin;
import org.elasticsearch.test.ESSingleNodeTestCase;
import org.elasticsearch.test.InternalSettingsPlugin;

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

import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.not;

public class MetadataMappingServiceTests extends ESSingleNodeTestCase {

    @Override
    protected Collection<Class<? extends Plugin>> getPlugins() {
        return Collections.singleton(InternalSettingsPlugin.class);
    }

    public void testMappingClusterStateUpdateDoesntChangeExistingIndices() throws Exception {
        final IndexService indexService = createIndex("test", client().admin().indices().prepareCreate("test").setMapping());
        final CompressedXContent currentMapping = indexService.mapperService().documentMapper().mappingSource();

        final MetadataMappingService mappingService = getInstanceFromNode(MetadataMappingService.class);
        final MetadataMappingService.PutMappingExecutor putMappingExecutor = mappingService.new PutMappingExecutor();
        final ClusterService clusterService = getInstanceFromNode(ClusterService.class);
        // TODO - it will be nice to get a random mapping generator
        final PutMappingClusterStateUpdateRequest request = new PutMappingClusterStateUpdateRequest("""
            { "properties": { "field": { "type": "text" }}}""");
        request.indices(new Index[] { indexService.index() });
        final var resultingState = ClusterStateTaskExecutorUtils.executeAndAssertSuccessful(
            clusterService.state(),
            putMappingExecutor,
            singleTask(request)
        );
        // the task really was a mapping update
        assertThat(
            indexService.mapperService().documentMapper().mappingSource(),
            not(equalTo(resultingState.metadata().index("test").mapping().source()))
        );
        // since we never committed the cluster state update, the in-memory state is unchanged
        assertThat(indexService.mapperService().documentMapper().mappingSource(), equalTo(currentMapping));
    }

    public void testClusterStateIsNotChangedWithIdenticalMappings() throws Exception {
        final IndexService indexService = createIndex("test", client().admin().indices().prepareCreate("test"));

        final MetadataMappingService mappingService = getInstanceFromNode(MetadataMappingService.class);
        final MetadataMappingService.PutMappingExecutor putMappingExecutor = mappingService.new PutMappingExecutor();
        final ClusterService clusterService = getInstanceFromNode(ClusterService.class);
        final PutMappingClusterStateUpdateRequest request = new PutMappingClusterStateUpdateRequest("""
            { "properties": { "field": { "type": "text" }}}""").indices(new Index[] { indexService.index() });
        final var resultingState1 = ClusterStateTaskExecutorUtils.executeAndAssertSuccessful(
            clusterService.state(),
            putMappingExecutor,
            singleTask(request)
        );
        final var resultingState2 = ClusterStateTaskExecutorUtils.executeAndAssertSuccessful(
            resultingState1,
            putMappingExecutor,
            singleTask(request)
        );
        assertSame(resultingState1, resultingState2);
    }

    public void testMappingVersion() throws Exception {
        final IndexService indexService = createIndex("test", client().admin().indices().prepareCreate("test"));
        final long previousVersion = indexService.getMetadata().getMappingVersion();
        final MetadataMappingService mappingService = getInstanceFromNode(MetadataMappingService.class);
        final MetadataMappingService.PutMappingExecutor putMappingExecutor = mappingService.new PutMappingExecutor();
        final ClusterService clusterService = getInstanceFromNode(ClusterService.class);
        final PutMappingClusterStateUpdateRequest request = new PutMappingClusterStateUpdateRequest("""
            { "properties": { "field": { "type": "text" }}}""");
        request.indices(new Index[] { indexService.index() });
        final var resultingState = ClusterStateTaskExecutorUtils.executeAndAssertSuccessful(
            clusterService.state(),
            putMappingExecutor,
            singleTask(request)
        );
        assertThat(resultingState.metadata().index("test").getMappingVersion(), equalTo(1 + previousVersion));
    }

    public void testMappingVersionUnchanged() throws Exception {
        final IndexService indexService = createIndex("test", client().admin().indices().prepareCreate("test").setMapping());
        final long previousVersion = indexService.getMetadata().getMappingVersion();
        final MetadataMappingService mappingService = getInstanceFromNode(MetadataMappingService.class);
        final MetadataMappingService.PutMappingExecutor putMappingExecutor = mappingService.new PutMappingExecutor();
        final ClusterService clusterService = getInstanceFromNode(ClusterService.class);
        final PutMappingClusterStateUpdateRequest request = new PutMappingClusterStateUpdateRequest("{ \"properties\": {}}");
        request.indices(new Index[] { indexService.index() });
        final var resultingState = ClusterStateTaskExecutorUtils.executeAndAssertSuccessful(
            clusterService.state(),
            putMappingExecutor,
            singleTask(request)
        );
        assertThat(resultingState.metadata().index("test").getMappingVersion(), equalTo(previousVersion));
    }

    private static List<MetadataMappingService.PutMappingClusterStateUpdateTask> singleTask(PutMappingClusterStateUpdateRequest request) {
        return Collections.singletonList(new MetadataMappingService.PutMappingClusterStateUpdateTask(request, ActionListener.running(() -> {
            throw new AssertionError("task should not complete publication");
        })));
    }

}
