/*
 * 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.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.Version;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.metadata.IndexMetadata;
import org.elasticsearch.cluster.metadata.Metadata;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.cluster.routing.RoutingNodes;
import org.elasticsearch.cluster.routing.RoutingTable;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.cluster.ESAllocationTestCase;

import static org.elasticsearch.cluster.routing.ShardRoutingState.INITIALIZING;
import static org.elasticsearch.cluster.routing.ShardRoutingState.STARTED;
import static org.elasticsearch.cluster.routing.ShardRoutingState.UNASSIGNED;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.nullValue;

public class ReplicaAllocatedAfterPrimaryTests extends ESAllocationTestCase {
    private final Logger logger = LogManager.getLogger(ReplicaAllocatedAfterPrimaryTests.class);

    public void testBackupIsAllocatedAfterPrimary() {
        AllocationService strategy = createAllocationService(Settings.builder()
            .put("cluster.routing.allocation.node_concurrent_recoveries", 10).build());

        logger.info("Building initial routing table");

        Metadata metadata = Metadata.builder()
                .put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1))
                .build();

        RoutingTable routingTable = RoutingTable.builder()
                .addAsNew(metadata.index("test"))
                .build();

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

        assertThat(routingTable.index("test").shards().size(), equalTo(1));
        assertThat(routingTable.index("test").shard(0).size(), equalTo(2));
        assertThat(routingTable.index("test").shard(0).shards().size(), equalTo(2));
        assertThat(routingTable.index("test").shard(0).shards().get(0).state(), equalTo(UNASSIGNED));
        assertThat(routingTable.index("test").shard(0).shards().get(1).state(), equalTo(UNASSIGNED));
        assertThat(routingTable.index("test").shard(0).shards().get(0).currentNodeId(), nullValue());
        assertThat(routingTable.index("test").shard(0).shards().get(1).currentNodeId(), nullValue());

        logger.info("Adding one node and performing rerouting");
        clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder()
            .add(newNode("node1")).add(newNode("node2"))).build();

        RoutingTable prevRoutingTable = routingTable;
        routingTable = strategy.reroute(clusterState, "reroute").routingTable();
        clusterState = ClusterState.builder(clusterState).routingTable(routingTable).build();
        final String nodeHoldingPrimary = routingTable.index("test").shard(0).primaryShard().currentNodeId();


        assertThat(prevRoutingTable != routingTable, equalTo(true));
        assertThat(routingTable.index("test").shards().size(), equalTo(1));
        assertThat(routingTable.index("test").shard(0).size(), equalTo(2));
        assertThat(routingTable.index("test").shard(0).shards().size(), equalTo(2));
        assertThat(routingTable.index("test").shard(0).primaryShard().state(), equalTo(INITIALIZING));
        assertThat(routingTable.index("test").shard(0).primaryShard().currentNodeId(), equalTo(nodeHoldingPrimary));
        assertThat(routingTable.index("test").shard(0).replicaShards().size(), equalTo(1));
        assertThat(routingTable.index("test").shard(0).replicaShards().get(0).state(), equalTo(UNASSIGNED));
        assertThat(routingTable.index("test").shard(0).replicaShards().get(0).currentNodeId(), nullValue());

        logger.info("Start all the primary shards");
        RoutingNodes routingNodes = clusterState.getRoutingNodes();
        prevRoutingTable = routingTable;
        routingTable = startInitializingShardsAndReroute(strategy, clusterState, routingNodes.node(nodeHoldingPrimary)).routingTable();
        final String nodeHoldingReplica = routingTable.index("test").shard(0).replicaShards().get(0).currentNodeId();
        assertThat(nodeHoldingPrimary, not(equalTo(nodeHoldingReplica)));
        assertThat(prevRoutingTable != routingTable, equalTo(true));
        assertThat(routingTable.index("test").shards().size(), equalTo(1));
        assertThat(routingTable.index("test").shard(0).size(), equalTo(2));
        assertThat(routingTable.index("test").shard(0).shards().size(), equalTo(2));
        assertThat(routingTable.index("test").shard(0).primaryShard().state(), equalTo(STARTED));
        assertThat(routingTable.index("test").shard(0).primaryShard().currentNodeId(), equalTo(nodeHoldingPrimary));
        assertThat(routingTable.index("test").shard(0).replicaShards().size(), equalTo(1));
        assertThat(routingTable.index("test").shard(0).replicaShards().get(0).state(), equalTo(INITIALIZING));
        assertThat(routingTable.index("test").shard(0).replicaShards().get(0).currentNodeId(), equalTo(nodeHoldingReplica));

    }
}
