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

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * 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
 * not use this file except in compliance with the License.
 * 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
 * specific language governing permissions and limitations
 * under the License.
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/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.indices;

import org.opensearch.OpenSearchException;
import org.opensearch.action.admin.cluster.state.ClusterStateResponse;
import org.opensearch.cluster.ClusterState;
import org.opensearch.cluster.metadata.IndexMetadata;
import org.opensearch.cluster.routing.ShardRouting;
import org.opensearch.cluster.routing.ShardRoutingState;
import org.opensearch.cluster.routing.allocation.command.MoveAllocationCommand;
import org.opensearch.cluster.routing.allocation.decider.EnableAllocationDecider;
import org.opensearch.common.CheckedRunnable;
import org.opensearch.common.Nullable;
import org.opensearch.common.settings.Settings;
import org.opensearch.core.common.Strings;
import org.opensearch.core.index.Index;
import org.opensearch.core.index.shard.ShardId;
import org.opensearch.index.shard.IndexEventListener;
import org.opensearch.index.shard.IndexShard;
import org.opensearch.index.shard.IndexShardState;
import org.opensearch.plugins.Plugin;
import org.opensearch.test.MockIndexEventListener;
import org.opensearch.test.OpenSearchIntegTestCase;
import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
import org.opensearch.test.OpenSearchIntegTestCase.Scope;
import org.hamcrest.Matchers;

import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
import static org.opensearch.index.shard.IndexShardState.CLOSED;
import static org.opensearch.index.shard.IndexShardState.CREATED;
import static org.opensearch.index.shard.IndexShardState.POST_RECOVERY;
import static org.opensearch.index.shard.IndexShardState.RECOVERING;
import static org.opensearch.index.shard.IndexShardState.STARTED;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;
import static org.hamcrest.Matchers.hasSize;

@ClusterScope(scope = Scope.TEST, numDataNodes = 0)
public class IndicesLifecycleListenerIT extends OpenSearchIntegTestCase {

    @Override
    protected Collection<Class<? extends Plugin>> nodePlugins() {
        return Arrays.asList(MockIndexEventListener.TestPlugin.class);
    }

    public void testBeforeIndexAddedToCluster() throws Exception {
        String node1 = internalCluster().startNode();
        String node2 = internalCluster().startNode();
        String node3 = internalCluster().startNode();

        final AtomicInteger beforeAddedCount = new AtomicInteger(0);
        final AtomicInteger allCreatedCount = new AtomicInteger(0);

        IndexEventListener listener = new IndexEventListener() {
            @Override
            public void beforeIndexAddedToCluster(Index index, Settings indexSettings) {
                beforeAddedCount.incrementAndGet();
                if (MockIndexEventListener.TestPlugin.INDEX_FAIL.get(indexSettings)) {
                    throw new OpenSearchException("failing on purpose");
                }
            }

            @Override
            public void beforeIndexCreated(Index index, Settings indexSettings) {
                allCreatedCount.incrementAndGet();
            }
        };

        internalCluster().getInstance(MockIndexEventListener.TestEventListener.class, node1).setNewDelegate(listener);
        internalCluster().getInstance(MockIndexEventListener.TestEventListener.class, node2).setNewDelegate(listener);
        internalCluster().getInstance(MockIndexEventListener.TestEventListener.class, node3).setNewDelegate(listener);

        client().admin()
            .indices()
            .prepareCreate("test")
            .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 3).put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
            .get();
        ensureGreen("test");
        assertThat("beforeIndexAddedToCluster called only once", beforeAddedCount.get(), equalTo(1));
        assertThat("beforeIndexCreated called on each data node", allCreatedCount.get(), greaterThanOrEqualTo(3));

        try {
            client().admin().indices().prepareCreate("failed").setSettings(Settings.builder().put("index.fail", true)).get();
            fail("should have thrown an exception during creation");
        } catch (Exception e) {
            assertTrue(e.getMessage().contains("failing on purpose"));
            ClusterStateResponse resp = client().admin().cluster().prepareState().get();
            assertFalse(resp.getState().routingTable().indicesRouting().keySet().contains("failed"));
        }
    }

    /**
     * Tests that if an *index* structure creation fails on relocation to a new node, the shard
     * is not stuck but properly failed.
     */
    public void testIndexShardFailedOnRelocation() throws Throwable {
        String node1 = internalCluster().startNode();
        client().admin()
            .indices()
            .prepareCreate("index1")
            .setSettings(Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put(SETTING_NUMBER_OF_REPLICAS, 0))
            .get();
        ensureGreen("index1");
        String node2 = internalCluster().startNode();
        internalCluster().getInstance(MockIndexEventListener.TestEventListener.class, node2)
            .setNewDelegate(new IndexShardStateChangeListener() {
                @Override
                public void beforeIndexCreated(Index index, Settings indexSettings) {
                    throw new RuntimeException("FAIL");
                }
            });
        client().admin().cluster().prepareReroute().add(new MoveAllocationCommand("index1", 0, node1, node2)).get();
        ensureGreen("index1");
        ClusterState state = client().admin().cluster().prepareState().get().getState();
        List<ShardRouting> shard = state.getRoutingNodes().shardsWithState(ShardRoutingState.STARTED);
        assertThat(shard, hasSize(1));
        assertThat(state.nodes().resolveNode(shard.get(0).currentNodeId()).getName(), Matchers.equalTo(node1));
    }

    public void testIndexStateShardChanged() throws Throwable {
        // start with a single node
        String node1 = internalCluster().startNode();
        IndexShardStateChangeListener stateChangeListenerNode1 = new IndexShardStateChangeListener();
        // add a listener that keeps track of the shard state changes
        internalCluster().getInstance(MockIndexEventListener.TestEventListener.class, node1).setNewDelegate(stateChangeListenerNode1);

        // create an index that should fail
        try {
            client().admin()
                .indices()
                .prepareCreate("failed")
                .setSettings(Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 1).put("index.fail", true))
                .get();
            fail("should have thrown an exception");
        } catch (OpenSearchException e) {
            assertTrue(e.getMessage().contains("failing on purpose"));
            ClusterStateResponse resp = client().admin().cluster().prepareState().get();
            assertFalse(resp.getState().routingTable().indicesRouting().keySet().contains("failed"));
        }

        // create an index
        assertAcked(
            client().admin()
                .indices()
                .prepareCreate("test")
                .setSettings(Settings.builder().put(SETTING_NUMBER_OF_SHARDS, 6).put(SETTING_NUMBER_OF_REPLICAS, 0))
        );
        ensureGreen();
        assertThat(stateChangeListenerNode1.creationSettings.getAsInt(SETTING_NUMBER_OF_SHARDS, -1), equalTo(6));
        assertThat(stateChangeListenerNode1.creationSettings.getAsInt(SETTING_NUMBER_OF_REPLICAS, -1), equalTo(0));

        // new shards got started
        assertShardStatesMatch(stateChangeListenerNode1, 6, CREATED, RECOVERING, POST_RECOVERY, STARTED);

        // add a node: 3 out of the 6 shards will be relocated to it
        // disable allocation before starting a new node, as we need to register the listener first
        assertAcked(
            client().admin()
                .cluster()
                .prepareUpdateSettings()
                .setPersistentSettings(
                    Settings.builder().put(EnableAllocationDecider.CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING.getKey(), "none")
                )
        );
        String node2 = internalCluster().startNode();
        IndexShardStateChangeListener stateChangeListenerNode2 = new IndexShardStateChangeListener();
        // add a listener that keeps track of the shard state changes
        internalCluster().getInstance(MockIndexEventListener.TestEventListener.class, node2).setNewDelegate(stateChangeListenerNode2);
        // re-enable allocation
        assertAcked(
            client().admin()
                .cluster()
                .prepareUpdateSettings()
                .setPersistentSettings(
                    Settings.builder().put(EnableAllocationDecider.CLUSTER_ROUTING_ALLOCATION_ENABLE_SETTING.getKey(), "all")
                )
        );
        ensureGreen();

        // the 3 relocated shards get closed on the first node
        assertShardStatesMatch(stateChangeListenerNode1, 3, CLOSED);
        // the 3 relocated shards get created on the second node
        assertShardStatesMatch(stateChangeListenerNode2, 3, CREATED, RECOVERING, POST_RECOVERY, STARTED);

        // increase replicas from 0 to 1
        assertAcked(
            client().admin().indices().prepareUpdateSettings("test").setSettings(Settings.builder().put(SETTING_NUMBER_OF_REPLICAS, 1))
        );
        ensureGreen();

        // 3 replicas are allocated to the first node
        assertShardStatesMatch(stateChangeListenerNode1, 3, CREATED, RECOVERING, POST_RECOVERY, STARTED);

        // 3 replicas are allocated to the second node
        assertShardStatesMatch(stateChangeListenerNode2, 3, CREATED, RECOVERING, POST_RECOVERY, STARTED);

        // close the index
        assertAcked(client().admin().indices().prepareClose("test"));

        assertThat(stateChangeListenerNode1.afterCloseSettings.getAsInt(SETTING_NUMBER_OF_SHARDS, -1), equalTo(6));
        assertThat(stateChangeListenerNode1.afterCloseSettings.getAsInt(SETTING_NUMBER_OF_REPLICAS, -1), equalTo(1));

        assertShardStatesMatch(stateChangeListenerNode1, 6, CLOSED, CREATED, RECOVERING, POST_RECOVERY, STARTED);
        assertShardStatesMatch(stateChangeListenerNode2, 6, CLOSED, CREATED, RECOVERING, POST_RECOVERY, STARTED);
    }

    private static void assertShardStatesMatch(
        final IndexShardStateChangeListener stateChangeListener,
        final int numShards,
        final IndexShardState... shardStates
    ) throws Exception {
        CheckedRunnable<Exception> waitPredicate = () -> {
            assertEquals(stateChangeListener.shardStates.size(), numShards);

            for (List<IndexShardState> indexShardStates : stateChangeListener.shardStates.values()) {
                assertNotNull(indexShardStates);
                assertThat(indexShardStates.size(), equalTo(shardStates.length));

                for (int i = 0; i < shardStates.length; i++) {
                    assertThat(indexShardStates.get(i), equalTo(shardStates[i]));
                }
            }
        };

        try {
            assertBusy(waitPredicate, 1, TimeUnit.MINUTES);
        } catch (AssertionError ae) {
            fail(
                "failed to observe expect shard states\n"
                    + "expected: ["
                    + numShards
                    + "] shards with states: "
                    + Strings.arrayToCommaDelimitedString(shardStates)
                    + "\n"
                    + "observed:\n"
                    + stateChangeListener
            );
        }

        stateChangeListener.shardStates.clear();
    }

    private static class IndexShardStateChangeListener implements IndexEventListener {
        // we keep track of all the states (ordered) a shard goes through
        final ConcurrentMap<ShardId, List<IndexShardState>> shardStates = new ConcurrentHashMap<>();
        Settings creationSettings = Settings.EMPTY;
        Settings afterCloseSettings = Settings.EMPTY;

        @Override
        public void indexShardStateChanged(
            IndexShard indexShard,
            @Nullable IndexShardState previousState,
            IndexShardState newState,
            @Nullable String reason
        ) {
            List<IndexShardState> shardStates = this.shardStates.putIfAbsent(
                indexShard.shardId(),
                new CopyOnWriteArrayList<>(new IndexShardState[] { newState })
            );
            if (shardStates != null) {
                shardStates.add(newState);
            }
        }

        @Override
        public void beforeIndexCreated(Index index, Settings indexSettings) {
            this.creationSettings = indexSettings;
            if (indexSettings.getAsBoolean("index.fail", false)) {
                throw new OpenSearchException("failing on purpose");
            }
        }

        @Override
        public void afterIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {
            this.afterCloseSettings = indexSettings;
        }

        @Override
        public String toString() {
            StringBuilder sb = new StringBuilder();
            for (Map.Entry<ShardId, List<IndexShardState>> entry : shardStates.entrySet()) {
                sb.append(entry.getKey()).append(" --> ").append(Strings.collectionToCommaDelimitedString(entry.getValue())).append("\n");
            }
            return sb.toString();
        }
    }
}
