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

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 * Licensed to Elasticsearch under one or more contributor
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 * 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
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 * 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
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/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.cluster.routing.allocation;

import org.opensearch.Version;
import org.opensearch.cluster.ClusterState;
import org.opensearch.cluster.OpenSearchAllocationTestCase;
import org.opensearch.cluster.metadata.IndexMetadata;
import org.opensearch.cluster.metadata.Metadata;
import org.opensearch.cluster.node.DiscoveryNodes;
import org.opensearch.cluster.routing.RoutingTable;
import org.opensearch.cluster.routing.ShardRouting;
import org.opensearch.common.settings.Settings;

import static java.util.Collections.singletonMap;
import static org.opensearch.cluster.routing.ShardRoutingState.INITIALIZING;
import static org.opensearch.cluster.routing.ShardRoutingState.RELOCATING;
import static org.opensearch.cluster.routing.ShardRoutingState.STARTED;
import static org.opensearch.cluster.routing.ShardRoutingState.UNASSIGNED;
import static org.hamcrest.Matchers.equalTo;

public class PreferLocalPrimariesToRelocatingPrimariesTests extends OpenSearchAllocationTestCase {

    public void testPreferLocalPrimaryAllocationOverFiltered() {
        int concurrentRecoveries = randomIntBetween(1, 10);
        int primaryRecoveries = randomIntBetween(1, 10);
        int numberOfShards = randomIntBetween(5, 20);
        int totalNumberOfShards = numberOfShards * 2;

        logger.info(
            "create an allocation with [{}] initial primary recoveries and [{}] concurrent recoveries",
            primaryRecoveries,
            concurrentRecoveries
        );
        AllocationService strategy = createAllocationService(
            Settings.builder()
                .put("cluster.routing.allocation.node_concurrent_recoveries", concurrentRecoveries)
                .put("cluster.routing.allocation.node_initial_primaries_recoveries", primaryRecoveries)
                .build()
        );

        logger.info("create 2 indices with [{}] no replicas, and wait till all are allocated", numberOfShards);

        Metadata metadata = Metadata.builder()
            .put(IndexMetadata.builder("test1").settings(settings(Version.CURRENT)).numberOfShards(numberOfShards).numberOfReplicas(0))
            .put(IndexMetadata.builder("test2").settings(settings(Version.CURRENT)).numberOfShards(numberOfShards).numberOfReplicas(0))
            .build();

        RoutingTable initialRoutingTable = RoutingTable.builder()
            .addAsNew(metadata.index("test1"))
            .addAsNew(metadata.index("test2"))
            .build();

        ClusterState clusterState = ClusterState.builder(org.opensearch.cluster.ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
            .metadata(metadata)
            .routingTable(initialRoutingTable)
            .build();

        logger.info("adding two nodes and performing rerouting till all are allocated");
        clusterState = ClusterState.builder(clusterState)
            .nodes(DiscoveryNodes.builder().add(newNode("node1")).add(newNode("node2")))
            .build();

        clusterState = strategy.reroute(clusterState, "reroute");

        while (clusterState.getRoutingNodes().shardsWithState(INITIALIZING).isEmpty() == false) {
            clusterState = startInitializingShardsAndReroute(strategy, clusterState);
        }

        logger.info("remove one of the nodes and apply filter to move everything from another node");

        metadata = Metadata.builder()
            .put(
                IndexMetadata.builder(clusterState.metadata().index("test1"))
                    .settings(
                        settings(Version.CURRENT).put("index.number_of_shards", numberOfShards)
                            .put("index.number_of_replicas", 0)
                            .put("index.routing.allocation.exclude._name", "node2")
                            .build()
                    )
            )
            .put(
                IndexMetadata.builder(clusterState.metadata().index("test2"))
                    .settings(
                        settings(Version.CURRENT).put("index.number_of_shards", numberOfShards)
                            .put("index.number_of_replicas", 0)
                            .put("index.routing.allocation.exclude._name", "node2")
                            .build()
                    )
            )
            .build();
        clusterState = ClusterState.builder(clusterState)
            .metadata(metadata)
            .nodes(DiscoveryNodes.builder(clusterState.nodes()).remove("node1"))
            .build();
        clusterState = strategy.disassociateDeadNodes(clusterState, true, "reroute");

        logger.info("[{}] primaries should be still started but [{}] other primaries should be unassigned", numberOfShards, numberOfShards);
        assertThat(clusterState.getRoutingNodes().shardsWithState(STARTED).size(), equalTo(numberOfShards));
        assertThat(clusterState.getRoutingNodes().shardsWithState(INITIALIZING).size(), equalTo(0));
        assertThat(clusterState.routingTable().shardsWithState(UNASSIGNED).size(), equalTo(numberOfShards));

        logger.info("start node back up");
        clusterState = ClusterState.builder(clusterState)
            .nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("node1", singletonMap("tag1", "value1"))))
            .build();
        clusterState = strategy.reroute(clusterState, "reroute");

        while (clusterState.getRoutingNodes().shardsWithState(STARTED).size() < totalNumberOfShards) {
            int localInitializations = 0;
            int relocatingInitializations = 0;
            for (ShardRouting routing : clusterState.getRoutingNodes().shardsWithState(INITIALIZING)) {
                if (routing.relocatingNodeId() == null) {
                    localInitializations++;
                } else {
                    relocatingInitializations++;
                }
            }
            int needToInitialize = totalNumberOfShards - clusterState.getRoutingNodes().shardsWithState(STARTED).size() - clusterState
                .getRoutingNodes()
                .shardsWithState(RELOCATING)
                .size();
            logger.info(
                "local initializations: [{}], relocating: [{}], need to initialize: {}",
                localInitializations,
                relocatingInitializations,
                needToInitialize
            );
            assertThat(localInitializations, equalTo(Math.min(primaryRecoveries, needToInitialize)));
            clusterState = startRandomInitializingShard(clusterState, strategy);
        }
    }
}