/*
 * 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.coordination;

import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
import org.elasticsearch.action.admin.cluster.node.stats.NodesStatsResponse;
import org.elasticsearch.action.admin.indices.recovery.RecoveryResponse;
import org.elasticsearch.common.Priority;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.discovery.DiscoveryStats;
import org.elasticsearch.test.ESIntegTestCase;
import org.elasticsearch.xcontent.ToXContent;
import org.elasticsearch.xcontent.XContentBuilder;
import org.elasticsearch.xcontent.XContentFactory;

import static org.elasticsearch.test.NodeRoles.dataNode;
import static org.elasticsearch.test.NodeRoles.masterOnlyNode;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.notNullValue;

@ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0, numClientNodes = 0)
public class ZenDiscoveryIT extends ESIntegTestCase {

    public void testNoShardRelocationsOccurWhenElectedMasterNodeFails() throws Exception {
        Settings masterNodeSettings = masterOnlyNode();
        internalCluster().startNodes(2, masterNodeSettings);
        Settings dateNodeSettings = dataNode();
        internalCluster().startNodes(2, dateNodeSettings);
        ClusterHealthResponse clusterHealthResponse = clusterAdmin().prepareHealth()
            .setWaitForEvents(Priority.LANGUID)
            .setWaitForNodes("4")
            .setWaitForNoRelocatingShards(true)
            .get();
        assertThat(clusterHealthResponse.isTimedOut(), is(false));

        createIndex("test");
        ensureSearchable("test");
        RecoveryResponse r = indicesAdmin().prepareRecoveries("test").get();
        int numRecoveriesBeforeNewMaster = r.shardRecoveryStates().get("test").size();

        final String oldMaster = internalCluster().getMasterName();
        internalCluster().stopCurrentMasterNode();
        assertBusy(() -> {
            String current = internalCluster().getMasterName();
            assertThat(current, notNullValue());
            assertThat(current, not(equalTo(oldMaster)));
        });
        ensureSearchable("test");

        r = indicesAdmin().prepareRecoveries("test").get();
        int numRecoveriesAfterNewMaster = r.shardRecoveryStates().get("test").size();
        assertThat(numRecoveriesAfterNewMaster, equalTo(numRecoveriesBeforeNewMaster));
    }

    public void testDiscoveryStats() throws Exception {
        internalCluster().startNode();
        ensureGreen(); // ensures that all events are processed (in particular state recovery fully completed)
        assertBusy(
            () -> assertThat(
                internalCluster().clusterService(internalCluster().getMasterName()).getMasterService().numberOfPendingTasks(),
                equalTo(0)
            )
        ); // see https://github.com/elastic/elasticsearch/issues/24388

        logger.info("--> request node discovery stats");
        NodesStatsResponse statsResponse = clusterAdmin().prepareNodesStats().clear().setDiscovery(true).get();
        assertThat(statsResponse.getNodes().size(), equalTo(1));

        DiscoveryStats stats = statsResponse.getNodes().get(0).getDiscoveryStats();
        assertThat(stats.getQueueStats(), notNullValue());
        assertThat(stats.getQueueStats().getTotal(), equalTo(0));
        assertThat(stats.getQueueStats().getCommitted(), equalTo(0));
        assertThat(stats.getQueueStats().getPending(), equalTo(0));

        assertThat(stats.getPublishStats(), notNullValue());
        assertThat(stats.getPublishStats().getFullClusterStateReceivedCount(), greaterThanOrEqualTo(0L));
        assertThat(stats.getPublishStats().getIncompatibleClusterStateDiffReceivedCount(), equalTo(0L));
        assertThat(stats.getPublishStats().getCompatibleClusterStateDiffReceivedCount(), greaterThanOrEqualTo(0L));

        XContentBuilder builder = XContentFactory.jsonBuilder().prettyPrint();
        builder.startObject();
        stats.toXContent(builder, ToXContent.EMPTY_PARAMS);
        builder.endObject();
    }
}
