/*
 * 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.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.action.support.single.instance;

import org.opensearch.ExceptionsHelper;
import org.opensearch.action.IndicesRequest;
import org.opensearch.action.support.ActionFilters;
import org.opensearch.action.support.PlainActionFuture;
import org.opensearch.action.support.replication.ClusterStateCreationUtils;
import org.opensearch.cluster.ClusterState;
import org.opensearch.cluster.block.ClusterBlock;
import org.opensearch.cluster.block.ClusterBlockException;
import org.opensearch.cluster.block.ClusterBlockLevel;
import org.opensearch.cluster.block.ClusterBlocks;
import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
import org.opensearch.cluster.metadata.ResolvedIndices;
import org.opensearch.cluster.node.DiscoveryNode;
import org.opensearch.cluster.routing.ShardIterator;
import org.opensearch.cluster.routing.ShardRoutingState;
import org.opensearch.cluster.service.ClusterService;
import org.opensearch.common.settings.Settings;
import org.opensearch.common.unit.TimeValue;
import org.opensearch.common.util.concurrent.ThreadContext;
import org.opensearch.core.action.ActionListener;
import org.opensearch.core.action.ActionResponse;
import org.opensearch.core.common.io.stream.StreamInput;
import org.opensearch.core.common.io.stream.StreamOutput;
import org.opensearch.core.common.io.stream.Writeable;
import org.opensearch.core.index.shard.ShardId;
import org.opensearch.core.rest.RestStatus;
import org.opensearch.telemetry.tracing.noop.NoopTracer;
import org.opensearch.test.OpenSearchTestCase;
import org.opensearch.test.transport.CapturingTransport;
import org.opensearch.threadpool.TestThreadPool;
import org.opensearch.threadpool.ThreadPool;
import org.opensearch.transport.ConnectTransportException;
import org.opensearch.transport.TransportException;
import org.opensearch.transport.TransportService;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;

import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import static org.opensearch.test.ClusterServiceUtils.createClusterService;
import static org.opensearch.test.ClusterServiceUtils.setState;
import static org.hamcrest.core.IsEqual.equalTo;

public class TransportInstanceSingleOperationActionTests extends OpenSearchTestCase {

    private static ThreadPool THREAD_POOL;

    private ClusterService clusterService;
    private CapturingTransport transport;
    private TransportService transportService;

    private TestTransportInstanceSingleOperationAction action;

    public static class Request extends InstanceShardOperationRequest<Request> {
        public Request() {}

        public Request(StreamInput in) throws IOException {
            super(null, in);
        }
    }

    public static class Response extends ActionResponse {
        public Response() {}

        public Response(StreamInput in) throws IOException {
            super(in);
        }

        @Override
        public void writeTo(StreamOutput out) throws IOException {}
    }

    class TestTransportInstanceSingleOperationAction extends TransportInstanceSingleOperationAction<Request, Response> {
        private final Map<ShardId, Object> shards = new HashMap<>();

        TestTransportInstanceSingleOperationAction(
            String actionName,
            TransportService transportService,
            ActionFilters actionFilters,
            IndexNameExpressionResolver indexNameExpressionResolver,
            Writeable.Reader<Request> request
        ) {
            super(
                actionName,
                THREAD_POOL,
                TransportInstanceSingleOperationActionTests.this.clusterService,
                transportService,
                actionFilters,
                indexNameExpressionResolver,
                request
            );
        }

        public Map<ShardId, Object> getResults() {
            return shards;
        }

        @Override
        protected String executor(ShardId shardId) {
            return ThreadPool.Names.SAME;
        }

        @Override
        protected void shardOperation(Request request, ActionListener<Response> listener) {
            throw new UnsupportedOperationException("Not implemented in test class");
        }

        @Override
        protected Response newResponse(StreamInput in) throws IOException {
            return new Response();
        }

        @Override
        protected void resolveRequest(ClusterState state, Request request) {}

        @Override
        protected ShardIterator shards(ClusterState clusterState, Request request) {
            return clusterState.routingTable().index(request.concreteIndex()).shard(request.shardId.getId()).primaryShardIt();
        }
    }

    class MyResolver extends IndexNameExpressionResolver {
        MyResolver() {
            super(new ThreadContext(Settings.EMPTY));
        }

        @Override
        public String[] concreteIndexNames(ClusterState state, IndicesRequest request) {
            return request.indices();
        }
    }

    @BeforeClass
    public static void startThreadPool() {
        THREAD_POOL = new TestThreadPool(TransportInstanceSingleOperationActionTests.class.getSimpleName());
    }

    @Override
    @Before
    public void setUp() throws Exception {
        super.setUp();
        transport = new CapturingTransport();
        clusterService = createClusterService(THREAD_POOL);
        transportService = transport.createTransportService(
            clusterService.getSettings(),
            THREAD_POOL,
            TransportService.NOOP_TRANSPORT_INTERCEPTOR,
            x -> clusterService.localNode(),
            null,
            Collections.emptySet(),
            NoopTracer.INSTANCE
        );
        transportService.start();
        transportService.acceptIncomingRequests();
        action = new TestTransportInstanceSingleOperationAction(
            "indices:admin/test",
            transportService,
            new ActionFilters(new HashSet<>()),
            new MyResolver(),
            Request::new
        );
    }

    @Override
    @After
    public void tearDown() throws Exception {
        super.tearDown();
        clusterService.close();
        transportService.close();
    }

    @AfterClass
    public static void destroyThreadPool() {
        ThreadPool.terminate(THREAD_POOL, 30, TimeUnit.SECONDS);
        // since static must set to null to be eligible for collection
        THREAD_POOL = null;
    }

    public void testGlobalBlock() {
        Request request = new Request();
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        ClusterBlocks.Builder block = ClusterBlocks.builder()
            .addGlobalBlock(new ClusterBlock(1, "", false, true, false, RestStatus.SERVICE_UNAVAILABLE, ClusterBlockLevel.ALL));
        setState(clusterService, ClusterState.builder(clusterService.state()).blocks(block));
        try {
            action.new AsyncSingleAction(request, listener).start();
            listener.get();
            fail("expected ClusterBlockException");
        } catch (Exception e) {
            if (ExceptionsHelper.unwrap(e, ClusterBlockException.class) == null) {
                logger.info("expected ClusterBlockException  but got ", e);
                fail("expected ClusterBlockException");
            }
        }
    }

    public void testBasicRequestWorks() throws InterruptedException, ExecutionException, TimeoutException {
        Request request = new Request().index("test");
        request.shardId = new ShardId("test", "_na_", 0);
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        setState(clusterService, ClusterStateCreationUtils.state("test", randomBoolean(), ShardRoutingState.STARTED));
        action.new AsyncSingleAction(request, listener).start();
        assertThat(transport.capturedRequests().length, equalTo(1));
        transport.handleResponse(transport.capturedRequests()[0].requestId, new Response());
        listener.get();
    }

    public void testFailureWithoutRetry() throws Exception {
        Request request = new Request().index("test");
        request.shardId = new ShardId("test", "_na_", 0);
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        setState(clusterService, ClusterStateCreationUtils.state("test", randomBoolean(), ShardRoutingState.STARTED));

        action.new AsyncSingleAction(request, listener).start();
        assertThat(transport.capturedRequests().length, equalTo(1));
        long requestId = transport.capturedRequests()[0].requestId;
        transport.clear();
        // this should not trigger retry or anything and the listener should report exception immediately
        transport.handleRemoteError(
            requestId,
            new TransportException("a generic transport exception", new Exception("generic test exception"))
        );

        try {
            // result should return immediately
            assertTrue(listener.isDone());
            listener.get();
            fail("this should fail with a transport exception");
        } catch (ExecutionException t) {
            if (ExceptionsHelper.unwrap(t, TransportException.class) == null) {
                logger.info("expected TransportException  but got ", t);
                fail("expected and TransportException");
            }
        }
    }

    public void testSuccessAfterRetryWithClusterStateUpdate() throws Exception {
        Request request = new Request().index("test");
        request.shardId = new ShardId("test", "_na_", 0);
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        boolean local = randomBoolean();
        setState(clusterService, ClusterStateCreationUtils.state("test", local, ShardRoutingState.INITIALIZING));
        action.new AsyncSingleAction(request, listener).start();
        // this should fail because primary not initialized
        assertThat(transport.capturedRequests().length, equalTo(0));
        setState(clusterService, ClusterStateCreationUtils.state("test", local, ShardRoutingState.STARTED));
        // this time it should work
        assertThat(transport.capturedRequests().length, equalTo(1));
        transport.handleResponse(transport.capturedRequests()[0].requestId, new Response());
        listener.get();
    }

    public void testSuccessAfterRetryWithExceptionFromTransport() throws Exception {
        Request request = new Request().index("test");
        request.shardId = new ShardId("test", "_na_", 0);
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        boolean local = randomBoolean();
        setState(clusterService, ClusterStateCreationUtils.state("test", local, ShardRoutingState.STARTED));
        action.new AsyncSingleAction(request, listener).start();
        assertThat(transport.capturedRequests().length, equalTo(1));
        long requestId = transport.capturedRequests()[0].requestId;
        transport.clear();
        DiscoveryNode node = clusterService.state().getNodes().getLocalNode();
        transport.handleLocalError(requestId, new ConnectTransportException(node, "test exception"));
        // trigger cluster state observer
        setState(clusterService, ClusterStateCreationUtils.state("test", local, ShardRoutingState.STARTED));
        assertThat(transport.capturedRequests().length, equalTo(1));
        transport.handleResponse(transport.capturedRequests()[0].requestId, new Response());
        listener.get();
    }

    public void testRetryOfAnAlreadyTimedOutRequest() throws Exception {
        Request request = new Request().index("test").timeout(new TimeValue(0, TimeUnit.MILLISECONDS));
        request.shardId = new ShardId("test", "_na_", 0);
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        setState(clusterService, ClusterStateCreationUtils.state("test", randomBoolean(), ShardRoutingState.STARTED));
        action.new AsyncSingleAction(request, listener).start();
        assertThat(transport.capturedRequests().length, equalTo(1));
        long requestId = transport.capturedRequests()[0].requestId;
        transport.clear();
        DiscoveryNode node = clusterService.state().getNodes().getLocalNode();
        transport.handleLocalError(requestId, new ConnectTransportException(node, "test exception"));

        // wait until the timeout was triggered and we actually tried to send for the second time
        assertBusy(() -> assertThat(transport.capturedRequests().length, equalTo(1)));

        // let it fail the second time too
        requestId = transport.capturedRequests()[0].requestId;
        transport.handleLocalError(requestId, new ConnectTransportException(node, "test exception"));
        try {
            // result should return immediately
            assertTrue(listener.isDone());
            listener.get();
            fail("this should fail with a transport exception");
        } catch (ExecutionException t) {
            if (ExceptionsHelper.unwrap(t, ConnectTransportException.class) == null) {
                logger.info("expected ConnectTransportException  but got ", t);
                fail("expected and ConnectTransportException");
            }
        }
    }

    public void testUnresolvableRequestDoesNotHang() throws InterruptedException, ExecutionException, TimeoutException {
        action = new TestTransportInstanceSingleOperationAction(
            "indices:admin/test_unresolvable",
            transportService,
            new ActionFilters(new HashSet<>()),
            new MyResolver(),
            Request::new
        ) {
            @Override
            protected void resolveRequest(ClusterState state, Request request) {
                throw new IllegalStateException("request cannot be resolved");
            }
        };
        Request request = new Request().index("test");
        request.shardId = new ShardId("test", "_na_", 0);
        PlainActionFuture<Response> listener = new PlainActionFuture<>();
        setState(clusterService, ClusterStateCreationUtils.state("test", randomBoolean(), ShardRoutingState.STARTED));
        action.new AsyncSingleAction(request, listener).start();
        assertThat(transport.capturedRequests().length, equalTo(0));
        try {
            listener.get();
        } catch (Exception e) {
            if (ExceptionsHelper.unwrap(e, IllegalStateException.class) == null) {
                logger.info("expected IllegalStateException  but got ", e);
                fail("expected and IllegalStateException");
            }
        }
    }

    public void testResolveIndices() {
        Request request = new Request().index("test");
        request.shardId = new ShardId("test", "_na_", 0);
        setState(clusterService, ClusterStateCreationUtils.state("test", true, ShardRoutingState.STARTED));
        ResolvedIndices resolvedIndices = action.resolveIndices(request);
        assertEquals(ResolvedIndices.of("test"), resolvedIndices);
    }

    public void testResolveIndices_concreteIndex() {
        Request request = new Request().index("test");
        request.concreteIndex("concrete_value");
        request.shardId = new ShardId("test", "_na_", 0);
        setState(clusterService, ClusterStateCreationUtils.state("test", true, ShardRoutingState.STARTED));
        ResolvedIndices resolvedIndices = action.resolveIndices(request);
        assertEquals(ResolvedIndices.of("concrete_value"), resolvedIndices);
    }

    public void testResolveIndices_nonExisting() {
        Request request = new Request().index("test_non_existing");
        request.shardId = new ShardId("test_non_existing", "_na_", 0);
        setState(clusterService, ClusterStateCreationUtils.state("test", true, ShardRoutingState.STARTED));
        ResolvedIndices resolvedIndices = action.resolveIndices(request);
        assertEquals(ResolvedIndices.of("test_non_existing"), resolvedIndices);
    }
}
