/*
 * 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.cluster.service;

import org.apache.logging.log4j.message.ParameterizedMessage;
import org.opensearch.action.admin.cluster.tasks.PendingClusterTasksResponse;
import org.opensearch.cluster.AckedClusterStateUpdateTask;
import org.opensearch.cluster.ClusterState;
import org.opensearch.cluster.ClusterStateUpdateTask;
import org.opensearch.cluster.node.DiscoveryNode;
import org.opensearch.common.Nullable;
import org.opensearch.common.settings.Settings;
import org.opensearch.common.unit.TimeValue;
import org.opensearch.test.OpenSearchIntegTestCase;
import org.opensearch.test.OpenSearchIntegTestCase.ClusterScope;
import org.opensearch.test.OpenSearchIntegTestCase.Scope;

import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.greaterThan;
import static org.hamcrest.Matchers.greaterThanOrEqualTo;

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

    public void testAckedUpdateTask() throws Exception {
        internalCluster().startNode();
        ClusterService clusterService = internalCluster().getInstance(ClusterService.class);

        final AtomicBoolean allNodesAcked = new AtomicBoolean(false);
        final AtomicBoolean ackTimeout = new AtomicBoolean(false);
        final AtomicBoolean onFailure = new AtomicBoolean(false);
        final AtomicBoolean executed = new AtomicBoolean(false);
        final CountDownLatch latch = new CountDownLatch(1);
        final CountDownLatch processedLatch = new CountDownLatch(1);
        clusterService.submitStateUpdateTask("test", new AckedClusterStateUpdateTask<Void>(null, null) {
            @Override
            protected Void newResponse(boolean acknowledged) {
                return null;
            }

            @Override
            public boolean mustAck(DiscoveryNode discoveryNode) {
                return true;
            }

            @Override
            public void onAllNodesAcked(@Nullable Exception e) {
                allNodesAcked.set(true);
                latch.countDown();
            }

            @Override
            public void onAckTimeout() {
                ackTimeout.set(true);
                latch.countDown();
            }

            @Override
            public TimeValue ackTimeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public TimeValue timeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
                processedLatch.countDown();
            }

            @Override
            public ClusterState execute(ClusterState currentState) throws Exception {
                executed.set(true);
                return ClusterState.builder(currentState).build();
            }

            @Override
            public void onFailure(String source, Exception e) {
                logger.error(() -> new ParameterizedMessage("failed to execute callback in test {}", source), e);
                onFailure.set(true);
                latch.countDown();
            }
        });

        ensureGreen();
        assertThat(latch.await(1, TimeUnit.SECONDS), equalTo(true));

        assertThat(allNodesAcked.get(), equalTo(true));
        assertThat(ackTimeout.get(), equalTo(false));
        assertThat(executed.get(), equalTo(true));
        assertThat(onFailure.get(), equalTo(false));

        assertThat(processedLatch.await(1, TimeUnit.SECONDS), equalTo(true));
    }

    public void testAckedUpdateTaskSameClusterState() throws Exception {
        internalCluster().startNode();
        ClusterService clusterService = internalCluster().getInstance(ClusterService.class);

        final AtomicBoolean allNodesAcked = new AtomicBoolean(false);
        final AtomicBoolean ackTimeout = new AtomicBoolean(false);
        final AtomicBoolean onFailure = new AtomicBoolean(false);
        final AtomicBoolean executed = new AtomicBoolean(false);
        final CountDownLatch latch = new CountDownLatch(1);
        final CountDownLatch processedLatch = new CountDownLatch(1);
        clusterService.submitStateUpdateTask("test", new AckedClusterStateUpdateTask<Void>(null, null) {
            @Override
            protected Void newResponse(boolean acknowledged) {
                return null;
            }

            @Override
            public void onAllNodesAcked(@Nullable Exception e) {
                allNodesAcked.set(true);
                latch.countDown();
            }

            @Override
            public void onAckTimeout() {
                ackTimeout.set(true);
                latch.countDown();
            }

            @Override
            public TimeValue ackTimeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public TimeValue timeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
                processedLatch.countDown();
            }

            @Override
            public ClusterState execute(ClusterState currentState) throws Exception {
                executed.set(true);
                return currentState;
            }

            @Override
            public void onFailure(String source, Exception e) {
                logger.error(() -> new ParameterizedMessage("failed to execute callback in test {}", source), e);
                onFailure.set(true);
                latch.countDown();
            }
        });

        ensureGreen();
        assertThat(latch.await(1, TimeUnit.SECONDS), equalTo(true));

        assertThat(allNodesAcked.get(), equalTo(true));
        assertThat(ackTimeout.get(), equalTo(false));
        assertThat(executed.get(), equalTo(true));
        assertThat(onFailure.get(), equalTo(false));

        assertThat(processedLatch.await(1, TimeUnit.SECONDS), equalTo(true));
    }

    public void testAckedUpdateTaskNoAckExpected() throws Exception {
        internalCluster().startNode();
        ClusterService clusterService = internalCluster().getInstance(ClusterService.class);

        final AtomicBoolean allNodesAcked = new AtomicBoolean(false);
        final AtomicBoolean ackTimeout = new AtomicBoolean(false);
        final AtomicBoolean onFailure = new AtomicBoolean(false);
        final AtomicBoolean executed = new AtomicBoolean(false);
        final CountDownLatch latch = new CountDownLatch(1);
        clusterService.submitStateUpdateTask("test", new AckedClusterStateUpdateTask<Void>(null, null) {
            @Override
            protected Void newResponse(boolean acknowledged) {
                return null;
            }

            @Override
            public boolean mustAck(DiscoveryNode discoveryNode) {
                return false;
            }

            @Override
            public void onAllNodesAcked(@Nullable Exception e) {
                allNodesAcked.set(true);
                latch.countDown();
            }

            @Override
            public void onAckTimeout() {
                ackTimeout.set(true);
                latch.countDown();
            }

            @Override
            public TimeValue ackTimeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public TimeValue timeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {}

            @Override
            public ClusterState execute(ClusterState currentState) throws Exception {
                executed.set(true);
                return ClusterState.builder(currentState).build();
            }

            @Override
            public void onFailure(String source, Exception e) {
                logger.error(() -> new ParameterizedMessage("failed to execute callback in test {}", source), e);
                onFailure.set(true);
                latch.countDown();
            }
        });

        ensureGreen();
        assertThat(latch.await(1, TimeUnit.SECONDS), equalTo(true));

        assertThat(allNodesAcked.get(), equalTo(true));
        assertThat(ackTimeout.get(), equalTo(false));
        assertThat(executed.get(), equalTo(true));
        assertThat(onFailure.get(), equalTo(false));
    }

    public void testAckedUpdateTaskTimeoutZero() throws Exception {
        internalCluster().startNode();
        ClusterService clusterService = internalCluster().getInstance(ClusterService.class);

        final AtomicBoolean allNodesAcked = new AtomicBoolean(false);
        final AtomicBoolean ackTimeout = new AtomicBoolean(false);
        final AtomicBoolean onFailure = new AtomicBoolean(false);
        final AtomicBoolean executed = new AtomicBoolean(false);
        final CountDownLatch latch = new CountDownLatch(1);
        final CountDownLatch processedLatch = new CountDownLatch(1);
        clusterService.submitStateUpdateTask("test", new AckedClusterStateUpdateTask<Void>(null, null) {
            @Override
            protected Void newResponse(boolean acknowledged) {
                return null;
            }

            @Override
            public boolean mustAck(DiscoveryNode discoveryNode) {
                return false;
            }

            @Override
            public void onAllNodesAcked(@Nullable Exception e) {
                allNodesAcked.set(true);
                latch.countDown();
            }

            @Override
            public void onAckTimeout() {
                ackTimeout.set(true);
                latch.countDown();
            }

            @Override
            public TimeValue ackTimeout() {
                return TimeValue.timeValueSeconds(0);
            }

            @Override
            public TimeValue timeout() {
                return TimeValue.timeValueSeconds(10);
            }

            @Override
            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
                processedLatch.countDown();
            }

            @Override
            public ClusterState execute(ClusterState currentState) throws Exception {
                executed.set(true);
                return ClusterState.builder(currentState).build();
            }

            @Override
            public void onFailure(String source, Exception e) {
                logger.error(() -> new ParameterizedMessage("failed to execute callback in test {}", source), e);
                onFailure.set(true);
                latch.countDown();
            }
        });

        ensureGreen();
        assertThat(latch.await(1, TimeUnit.SECONDS), equalTo(true));

        assertThat(allNodesAcked.get(), equalTo(false));
        assertThat(ackTimeout.get(), equalTo(true));
        assertThat(executed.get(), equalTo(true));
        assertThat(onFailure.get(), equalTo(false));

        assertThat(processedLatch.await(1, TimeUnit.SECONDS), equalTo(true));
    }

    public void testPendingUpdateTask() throws Exception {
        String node_0 = internalCluster().startNode();
        internalCluster().startCoordinatingOnlyNode(Settings.EMPTY);

        final ClusterService clusterService = internalCluster().getInstance(ClusterService.class, node_0);
        final CountDownLatch block1 = new CountDownLatch(1);
        final CountDownLatch invoked1 = new CountDownLatch(1);
        clusterService.submitStateUpdateTask("1", new ClusterStateUpdateTask() {
            @Override
            public ClusterState execute(ClusterState currentState) {
                invoked1.countDown();
                try {
                    block1.await();
                } catch (InterruptedException e) {
                    fail();
                }
                return currentState;
            }

            @Override
            public void onFailure(String source, Exception e) {
                invoked1.countDown();
                fail();
            }
        });
        invoked1.await();
        final CountDownLatch invoked2 = new CountDownLatch(9);
        for (int i = 2; i <= 10; i++) {
            clusterService.submitStateUpdateTask(Integer.toString(i), new ClusterStateUpdateTask() {
                @Override
                public ClusterState execute(ClusterState currentState) {
                    return currentState;
                }

                @Override
                public void onFailure(String source, Exception e) {
                    fail();
                }

                @Override
                public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
                    invoked2.countDown();
                }
            });
        }

        // there might be other tasks in this node, make sure to only take the ones we add into account in this test

        // The tasks can be re-ordered, so we need to check out-of-order
        Set<String> controlSources = new HashSet<>(Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10"));
        List<PendingClusterTask> pendingClusterTasks = clusterService.getClusterManagerService().pendingTasks();
        assertThat(pendingClusterTasks.size(), greaterThanOrEqualTo(10));
        assertThat(pendingClusterTasks.get(0).getSource().string(), equalTo("1"));
        assertThat(pendingClusterTasks.get(0).isExecuting(), equalTo(true));
        for (PendingClusterTask task : pendingClusterTasks) {
            controlSources.remove(task.getSource().string());
        }
        assertTrue(controlSources.isEmpty());

        controlSources = new HashSet<>(Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10"));
        PendingClusterTasksResponse response = internalCluster().coordOnlyNodeClient().admin().cluster().preparePendingClusterTasks().get();
        assertThat(response.pendingTasks().size(), greaterThanOrEqualTo(10));
        assertThat(response.pendingTasks().get(0).getSource().string(), equalTo("1"));
        assertThat(response.pendingTasks().get(0).isExecuting(), equalTo(true));
        for (PendingClusterTask task : response) {
            controlSources.remove(task.getSource().string());
        }
        assertTrue(controlSources.isEmpty());
        block1.countDown();
        invoked2.await();

        // whenever we test for no tasks, we need to wait since this is a live node
        assertBusy(() -> assertTrue("Pending tasks not empty", clusterService.getClusterManagerService().pendingTasks().isEmpty()));
        waitNoPendingTasksOnAll();

        final CountDownLatch block2 = new CountDownLatch(1);
        final CountDownLatch invoked3 = new CountDownLatch(1);
        clusterService.submitStateUpdateTask("1", new ClusterStateUpdateTask() {
            @Override
            public ClusterState execute(ClusterState currentState) {
                invoked3.countDown();
                try {
                    block2.await();
                } catch (InterruptedException e) {
                    fail();
                }
                return currentState;
            }

            @Override
            public void onFailure(String source, Exception e) {
                invoked3.countDown();
                fail();
            }
        });
        invoked3.await();

        for (int i = 2; i <= 5; i++) {
            clusterService.submitStateUpdateTask(Integer.toString(i), new ClusterStateUpdateTask() {
                @Override
                public ClusterState execute(ClusterState currentState) {
                    return currentState;
                }

                @Override
                public void onFailure(String source, Exception e) {
                    fail();
                }
            });
        }
        Thread.sleep(100);

        pendingClusterTasks = clusterService.getClusterManagerService().pendingTasks();
        assertThat(pendingClusterTasks.size(), greaterThanOrEqualTo(5));
        controlSources = new HashSet<>(Arrays.asList("1", "2", "3", "4", "5"));
        for (PendingClusterTask task : pendingClusterTasks) {
            controlSources.remove(task.getSource().string());
        }
        assertTrue(controlSources.isEmpty());

        response = internalCluster().coordOnlyNodeClient().admin().cluster().preparePendingClusterTasks().get();
        assertThat(response.pendingTasks().size(), greaterThanOrEqualTo(5));
        controlSources = new HashSet<>(Arrays.asList("1", "2", "3", "4", "5"));
        for (PendingClusterTask task : response) {
            if (controlSources.remove(task.getSource().string())) {
                assertThat(task.getTimeInQueueInMillis(), greaterThan(0L));
            }
        }
        assertTrue(controlSources.isEmpty());
        block2.countDown();
    }
}
