/*
 * 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", the "GNU Affero General Public License v3.0 only", 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", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.cluster.routing.allocation;

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.RoutingNodes;
import org.elasticsearch.cluster.routing.RoutingTable;
import org.elasticsearch.cluster.routing.allocation.decider.ClusterRebalanceAllocationDecider;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.IndexVersion;

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;
import static org.hamcrest.Matchers.lessThan;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.nullValue;

public class TenShardsOneReplicaRoutingTests extends ESAllocationTestCase {

    public void testSingleIndexFirstStartPrimaryThenBackups() {
        AllocationService strategy = createAllocationService(
            Settings.builder()
                .put("cluster.routing.allocation.node_concurrent_recoveries", 10)
                .put("cluster.routing.allocation.node_initial_primaries_recoveries", 10)
                .put(ClusterRebalanceAllocationDecider.CLUSTER_ROUTING_ALLOCATION_ALLOW_REBALANCE_SETTING.getKey(), "always")
                .put("cluster.routing.allocation.cluster_concurrent_rebalance", -1)
                .put("cluster.routing.allocation.balance.index", 0.0f)
                .put("cluster.routing.allocation.balance.replica", 1.0f)
                .put("cluster.routing.allocation.balance.primary", 0.0f)
                .build()
        );

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

        Metadata metadata = Metadata.builder()
            .put(IndexMetadata.builder("test").settings(settings(IndexVersion.current())).numberOfShards(10).numberOfReplicas(1))
            .build();

        RoutingTable initialRoutingTable = RoutingTable.builder(TestShardRoutingRoleStrategies.DEFAULT_ROLE_ONLY)
            .addAsNew(metadata.getProject().index("test"))
            .build();

        ClusterState clusterState = ClusterState.builder(ClusterName.DEFAULT).metadata(metadata).routingTable(initialRoutingTable).build();

        assertThat(clusterState.routingTable().index("test").size(), equalTo(10));
        for (int i = 0; i < clusterState.routingTable().index("test").size(); i++) {
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).shard(0).state(), equalTo(UNASSIGNED));
            assertThat(clusterState.routingTable().index("test").shard(i).shard(1).state(), equalTo(UNASSIGNED));
            assertThat(clusterState.routingTable().index("test").shard(i).shard(0).currentNodeId(), nullValue());
            assertThat(clusterState.routingTable().index("test").shard(i).shard(1).currentNodeId(), nullValue());
        }

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

        ClusterState newState = strategy.reroute(clusterState, "reroute", ActionListener.noop());
        assertThat(newState, not(equalTo(clusterState)));
        clusterState = newState;

        assertThat(clusterState.routingTable().index("test").size(), equalTo(10));
        for (int i = 0; i < clusterState.routingTable().index("test").size(); i++) {
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).primaryShard().state(), equalTo(INITIALIZING));
            assertThat(clusterState.routingTable().index("test").shard(i).primaryShard().currentNodeId(), equalTo("node1"));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().size(), equalTo(1));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().get(0).state(), equalTo(UNASSIGNED));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().get(0).currentNodeId(), nullValue());
        }

        logger.info("Add another node and perform rerouting, nothing will happen since primary not started");
        clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("node2"))).build();
        newState = strategy.reroute(clusterState, "reroute", ActionListener.noop());
        assertThat(newState, equalTo(clusterState));

        logger.info("Start the primary shard (on node1)");
        RoutingNodes routingNodes = clusterState.getRoutingNodes();
        newState = startInitializingShardsAndReroute(strategy, clusterState, routingNodes.node("node1"));
        assertThat(newState, not(equalTo(clusterState)));
        clusterState = newState;

        assertThat(clusterState.routingTable().index("test").size(), equalTo(10));
        for (int i = 0; i < clusterState.routingTable().index("test").size(); i++) {
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).primaryShard().state(), equalTo(STARTED));
            assertThat(clusterState.routingTable().index("test").shard(i).primaryShard().currentNodeId(), equalTo("node1"));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().size(), equalTo(1));
            // backup shards are initializing as well, we make sure that they
            // recover from primary *started* shards in the IndicesClusterStateService
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().get(0).state(), equalTo(INITIALIZING));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().get(0).currentNodeId(), equalTo("node2"));
        }

        logger.info("Reroute, nothing should change");
        newState = strategy.reroute(clusterState, "reroute", ActionListener.noop());
        assertThat(newState, equalTo(clusterState));

        logger.info("Start the backup shard");
        routingNodes = clusterState.getRoutingNodes();
        newState = startInitializingShardsAndReroute(strategy, clusterState, routingNodes.node("node2"));
        assertThat(newState, not(equalTo(clusterState)));
        clusterState = newState;
        routingNodes = clusterState.getRoutingNodes();

        assertThat(clusterState.routingTable().index("test").size(), equalTo(10));
        for (int i = 0; i < clusterState.routingTable().index("test").size(); i++) {
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).size(), equalTo(2));
            assertThat(clusterState.routingTable().index("test").shard(i).primaryShard().state(), equalTo(STARTED));
            assertThat(clusterState.routingTable().index("test").shard(i).primaryShard().currentNodeId(), equalTo("node1"));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().size(), equalTo(1));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().get(0).state(), equalTo(STARTED));
            assertThat(clusterState.routingTable().index("test").shard(i).replicaShards().get(0).currentNodeId(), equalTo("node2"));
        }
        assertThat(routingNodes.node("node1").numberOfShardsWithState(STARTED), equalTo(10));
        assertThat(routingNodes.node("node2").numberOfShardsWithState(STARTED), equalTo(10));

        logger.info("Add another node and perform rerouting");
        clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder(clusterState.nodes()).add(newNode("node3"))).build();
        newState = strategy.reroute(clusterState, "reroute", ActionListener.noop());
        assertThat(newState, not(equalTo(clusterState)));
        clusterState = newState;
        routingNodes = clusterState.getRoutingNodes();

        assertThat(clusterState.routingTable().index("test").size(), equalTo(10));
        assertThat(routingNodes.node("node1").numberOfShardsWithState(STARTED), lessThan(10));
        assertThat(
            routingNodes.node("node1").numberOfShardsWithState(STARTED) + routingNodes.node("node1").numberOfShardsWithState(RELOCATING),
            equalTo(10)
        );
        assertThat(routingNodes.node("node2").numberOfShardsWithState(STARTED), lessThan(10));
        assertThat(
            routingNodes.node("node2").numberOfShardsWithState(STARTED) + routingNodes.node("node2").numberOfShardsWithState(RELOCATING),
            equalTo(10)
        );
        assertThat(routingNodes.node("node3").numberOfShardsWithState(INITIALIZING), equalTo(6));

        logger.info("Start the shards on node 3");
        routingNodes = clusterState.getRoutingNodes();
        newState = startInitializingShardsAndReroute(strategy, clusterState, routingNodes.node("node3"));
        assertThat(newState, not(equalTo(clusterState)));
        clusterState = newState;
        routingNodes = clusterState.getRoutingNodes();

        assertThat(clusterState.routingTable().index("test").size(), equalTo(10));
        assertThat(routingNodes.node("node1").numberOfShardsWithState(STARTED), equalTo(7));
        assertThat(routingNodes.node("node2").numberOfShardsWithState(STARTED), equalTo(7));
        assertThat(routingNodes.node("node3").numberOfShardsWithState(STARTED), equalTo(6));
    }
}