/*
 * 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.routing.allocation;

import org.elasticsearch.Version;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.cluster.ClusterName;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ESAllocationTestCase;
import org.elasticsearch.cluster.TestShardRoutingRoleStrategies;
import org.elasticsearch.cluster.metadata.IndexMetadata;
import org.elasticsearch.cluster.metadata.Metadata;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.cluster.routing.RoutingTable;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.common.settings.Settings;

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

public class PreferLocalPrimariesToRelocatingPrimariesTests extends ESAllocationTestCase {

    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(TestShardRoutingRoleStrategies.DEFAULT_ROLE_ONLY)
            .addAsNew(metadata.index("test1"))
            .addAsNew(metadata.index("test2"))
            .build();

        ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT).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", ActionListener.noop());

        while (shardsWithState(clusterState.getRoutingNodes(), 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(indexSettings(Version.CURRENT, numberOfShards, 0).put("index.routing.allocation.exclude._name", "node2"))
            )
            .put(
                IndexMetadata.builder(clusterState.metadata().index("test2"))
                    .settings(indexSettings(Version.CURRENT, numberOfShards, 0).put("index.routing.allocation.exclude._name", "node2"))
            )
            .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(shardsWithState(clusterState.getRoutingNodes(), STARTED).size(), equalTo(numberOfShards));
        assertThat(shardsWithState(clusterState.getRoutingNodes(), INITIALIZING).size(), equalTo(0));
        assertThat(shardsWithState(clusterState.getRoutingNodes(), 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", ActionListener.noop());

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