/*
 * 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.search;

import org.junit.After;
import org.junit.Before;
import org.opensearch.action.ActionListener;
import org.opensearch.action.OriginalIndices;
import org.opensearch.action.support.IndicesOptions;
import org.opensearch.cluster.ClusterState;
import org.opensearch.cluster.routing.GroupShardsIterator;
import org.opensearch.common.UUIDs;
import org.opensearch.common.collect.Tuple;
import org.opensearch.common.util.set.Sets;
import org.opensearch.core.index.Index;
import org.opensearch.index.query.MatchAllQueryBuilder;
import org.opensearch.core.index.shard.ShardId;
import org.opensearch.index.shard.ShardNotFoundException;
import org.opensearch.search.SearchPhaseResult;
import org.opensearch.search.SearchShardTarget;
import org.opensearch.search.internal.AliasFilter;
import org.opensearch.search.internal.InternalSearchResponse;
import org.opensearch.search.internal.ShardSearchContextId;
import org.opensearch.search.internal.ShardSearchRequest;
import org.opensearch.search.query.QuerySearchResult;
import org.opensearch.test.OpenSearchTestCase;
import org.opensearch.transport.Transport;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiFunction;
import java.util.stream.IntStream;

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

public class AbstractSearchAsyncActionTests extends OpenSearchTestCase {

    private final List<Tuple<String, String>> resolvedNodes = new ArrayList<>();
    private final Set<ShardSearchContextId> releasedContexts = new CopyOnWriteArraySet<>();
    private ExecutorService executor;

    @Before
    @Override
    public void setUp() throws Exception {
        super.setUp();
        executor = Executors.newFixedThreadPool(1);
    }

    @After
    @Override
    public void tearDown() throws Exception {
        super.tearDown();
        executor.shutdown();
        assertTrue(executor.awaitTermination(1, TimeUnit.SECONDS));
    }

    private AbstractSearchAsyncAction<SearchPhaseResult> createAction(
        SearchRequest request,
        ArraySearchPhaseResults<SearchPhaseResult> results,
        ActionListener<SearchResponse> listener,
        final boolean controlled,
        final AtomicLong expected
    ) {
        return createAction(
            request,
            results,
            listener,
            controlled,
            false,
            expected,
            new SearchShardIterator(null, null, Collections.emptyList(), null)
        );
    }

    private AbstractSearchAsyncAction<SearchPhaseResult> createAction(
        SearchRequest request,
        ArraySearchPhaseResults<SearchPhaseResult> results,
        ActionListener<SearchResponse> listener,
        final boolean controlled,
        final boolean failExecutePhaseOnShard,
        final AtomicLong expected,
        final SearchShardIterator... shards
    ) {
        final Runnable runnable;
        final TransportSearchAction.SearchTimeProvider timeProvider;
        if (controlled) {
            runnable = () -> expected.set(randomNonNegativeLong());
            timeProvider = new TransportSearchAction.SearchTimeProvider(0, 0, expected::get);
        } else {
            runnable = () -> {
                long elapsed = spinForAtLeastNMilliseconds(randomIntBetween(1, 10));
                expected.set(elapsed);
            };
            timeProvider = new TransportSearchAction.SearchTimeProvider(0, System.nanoTime(), System::nanoTime);
        }

        BiFunction<String, String, Transport.Connection> nodeIdToConnection = (cluster, node) -> {
            resolvedNodes.add(Tuple.tuple(cluster, node));
            return null;
        };

        return new AbstractSearchAsyncAction<SearchPhaseResult>(
            "test",
            logger,
            null,
            nodeIdToConnection,
            Collections.singletonMap("foo", new AliasFilter(new MatchAllQueryBuilder())),
            Collections.singletonMap("foo", 2.0f),
            Collections.singletonMap("name", Sets.newHashSet("bar", "baz")),
            executor,
            request,
            listener,
            new GroupShardsIterator<>(Arrays.asList(shards)),
            timeProvider,
            ClusterState.EMPTY_STATE,
            null,
            results,
            request.getMaxConcurrentShardRequests(),
            SearchResponse.Clusters.EMPTY
        ) {
            @Override
            protected SearchPhase getNextPhase(final SearchPhaseResults<SearchPhaseResult> results, SearchPhaseContext context) {
                return null;
            }

            @Override
            protected void executePhaseOnShard(
                final SearchShardIterator shardIt,
                final SearchShardTarget shard,
                final SearchActionListener<SearchPhaseResult> listener
            ) {
                if (failExecutePhaseOnShard) {
                    listener.onFailure(new ShardNotFoundException(shardIt.shardId()));
                } else {
                    listener.onResponse(new QuerySearchResult());
                }
            }

            @Override
            long buildTookInMillis() {
                runnable.run();
                return super.buildTookInMillis();
            }

            @Override
            public void sendReleaseSearchContext(
                ShardSearchContextId contextId,
                Transport.Connection connection,
                OriginalIndices originalIndices
            ) {
                releasedContexts.add(contextId);
            }
        };
    }

    public void testTookWithControlledClock() {
        runTestTook(true);
    }

    public void testTookWithRealClock() {
        runTestTook(false);
    }

    private void runTestTook(final boolean controlled) {
        final AtomicLong expected = new AtomicLong();
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
            new SearchRequest(),
            new ArraySearchPhaseResults<>(10),
            null,
            controlled,
            expected
        );
        final long actual = action.buildTookInMillis();
        if (controlled) {
            // with a controlled clock, we can assert the exact took time
            assertThat(actual, equalTo(TimeUnit.NANOSECONDS.toMillis(expected.get())));
        } else {
            // with a real clock, the best we can say is that it took as long as we spun for
            assertThat(actual, greaterThanOrEqualTo(TimeUnit.NANOSECONDS.toMillis(expected.get())));
        }
    }

    public void testBuildShardSearchTransportRequest() {
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(randomBoolean()).preference("_shards:1,3");
        final AtomicLong expected = new AtomicLong();
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
            searchRequest,
            new ArraySearchPhaseResults<>(10),
            null,
            false,
            expected
        );
        String clusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
        SearchShardIterator iterator = new SearchShardIterator(
            clusterAlias,
            new ShardId(new Index("name", "foo"), 1),
            Collections.emptyList(),
            new OriginalIndices(new String[] { "name", "name1" }, IndicesOptions.strictExpand())
        );
        ShardSearchRequest shardSearchTransportRequest = action.buildShardSearchRequest(iterator);
        assertEquals(IndicesOptions.strictExpand(), shardSearchTransportRequest.indicesOptions());
        assertArrayEquals(new String[] { "name", "name1" }, shardSearchTransportRequest.indices());
        assertEquals(new MatchAllQueryBuilder(), shardSearchTransportRequest.getAliasFilter().getQueryBuilder());
        assertEquals(2.0f, shardSearchTransportRequest.indexBoost(), 0.0f);
        assertArrayEquals(new String[] { "name", "name1" }, shardSearchTransportRequest.indices());
        assertArrayEquals(new String[] { "bar", "baz" }, shardSearchTransportRequest.indexRoutings());
        assertEquals("_shards:1,3", shardSearchTransportRequest.preference());
        assertEquals(clusterAlias, shardSearchTransportRequest.getClusterAlias());
    }

    public void testBuildSearchResponse() {
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(randomBoolean());
        ArraySearchPhaseResults<SearchPhaseResult> phaseResults = new ArraySearchPhaseResults<>(10);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(searchRequest, phaseResults, null, false, new AtomicLong());
        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
    }

    public void testBuildSearchResponseAllowPartialFailures() {
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(10);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(searchRequest, queryResult, null, false, new AtomicLong());
        action.onShardFailure(
            0,
            new SearchShardTarget("node", new ShardId("index", "index-uuid", 0), null, OriginalIndices.NONE),
            new IllegalArgumentException()
        );
        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
    }

    public void testSendSearchResponseDisallowPartialFailures() {
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(false);
        AtomicReference<Exception> exception = new AtomicReference<>();
        ActionListener<SearchResponse> listener = ActionListener.wrap(response -> fail("onResponse should not be called"), exception::set);
        Set<ShardSearchContextId> requestIds = new HashSet<>();
        List<Tuple<String, String>> nodeLookups = new ArrayList<>();
        int numFailures = randomIntBetween(1, 5);
        ArraySearchPhaseResults<SearchPhaseResult> phaseResults = phaseResults(requestIds, nodeLookups, numFailures);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(searchRequest, phaseResults, listener, false, new AtomicLong());
        for (int i = 0; i < numFailures; i++) {
            ShardId failureShardId = new ShardId("index", "index-uuid", i);
            String failureClusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
            String failureNodeId = randomAlphaOfLengthBetween(5, 10);
            action.onShardFailure(
                i,
                new SearchShardTarget(failureNodeId, failureShardId, failureClusterAlias, OriginalIndices.NONE),
                new IllegalArgumentException()
            );
        }
        action.sendSearchResponse(InternalSearchResponse.empty(), phaseResults.results);
        assertThat(exception.get(), instanceOf(SearchPhaseExecutionException.class));
        SearchPhaseExecutionException searchPhaseExecutionException = (SearchPhaseExecutionException) exception.get();
        assertEquals(0, searchPhaseExecutionException.getSuppressed().length);
        assertEquals(numFailures, searchPhaseExecutionException.shardFailures().length);
        for (ShardSearchFailure shardSearchFailure : searchPhaseExecutionException.shardFailures()) {
            assertThat(shardSearchFailure.getCause(), instanceOf(IllegalArgumentException.class));
        }
        assertEquals(nodeLookups, resolvedNodes);
        assertEquals(requestIds, releasedContexts);
    }

    public void testOnPhaseFailure() {
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(false);
        AtomicReference<Exception> exception = new AtomicReference<>();
        ActionListener<SearchResponse> listener = ActionListener.wrap(response -> fail("onResponse should not be called"), exception::set);
        Set<ShardSearchContextId> requestIds = new HashSet<>();
        List<Tuple<String, String>> nodeLookups = new ArrayList<>();
        ArraySearchPhaseResults<SearchPhaseResult> phaseResults = phaseResults(requestIds, nodeLookups, 0);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(searchRequest, phaseResults, listener, false, new AtomicLong());
        action.onPhaseFailure(new SearchPhase("test") {
            @Override
            public void run() {

            }
        }, "message", null);
        assertThat(exception.get(), instanceOf(SearchPhaseExecutionException.class));
        SearchPhaseExecutionException searchPhaseExecutionException = (SearchPhaseExecutionException) exception.get();
        assertEquals("message", searchPhaseExecutionException.getMessage());
        assertEquals("test", searchPhaseExecutionException.getPhaseName());
        assertEquals(0, searchPhaseExecutionException.shardFailures().length);
        assertEquals(0, searchPhaseExecutionException.getSuppressed().length);
        assertEquals(nodeLookups, resolvedNodes);
        assertEquals(requestIds, releasedContexts);
    }

    public void testShardNotAvailableWithDisallowPartialFailures() {
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(false);
        AtomicReference<Exception> exception = new AtomicReference<>();
        ActionListener<SearchResponse> listener = ActionListener.wrap(response -> fail("onResponse should not be called"), exception::set);
        int numShards = randomIntBetween(2, 10);
        ArraySearchPhaseResults<SearchPhaseResult> phaseResults = new ArraySearchPhaseResults<>(numShards);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(searchRequest, phaseResults, listener, false, new AtomicLong());
        // skip one to avoid the "all shards failed" failure.
        SearchShardIterator skipIterator = new SearchShardIterator(null, null, Collections.emptyList(), null);
        skipIterator.resetAndSkip();
        action.skipShard(skipIterator);
        // expect at least 2 shards, so onPhaseDone should report failure.
        action.onPhaseDone();
        assertThat(exception.get(), instanceOf(SearchPhaseExecutionException.class));
        SearchPhaseExecutionException searchPhaseExecutionException = (SearchPhaseExecutionException) exception.get();
        assertEquals("Partial shards failure (" + (numShards - 1) + " shards unavailable)", searchPhaseExecutionException.getMessage());
        assertEquals("test", searchPhaseExecutionException.getPhaseName());
        assertEquals(0, searchPhaseExecutionException.shardFailures().length);
        assertEquals(0, searchPhaseExecutionException.getSuppressed().length);
    }

    private static ArraySearchPhaseResults<SearchPhaseResult> phaseResults(
        Set<ShardSearchContextId> contextIds,
        List<Tuple<String, String>> nodeLookups,
        int numFailures
    ) {
        int numResults = randomIntBetween(1, 10);
        ArraySearchPhaseResults<SearchPhaseResult> phaseResults = new ArraySearchPhaseResults<>(numResults + numFailures);

        for (int i = 0; i < numResults; i++) {
            ShardSearchContextId contextId = new ShardSearchContextId(UUIDs.randomBase64UUID(), randomNonNegativeLong());
            contextIds.add(contextId);
            SearchPhaseResult phaseResult = new PhaseResult(contextId);
            String resultClusterAlias = randomBoolean() ? null : randomAlphaOfLengthBetween(5, 10);
            String resultNodeId = randomAlphaOfLengthBetween(5, 10);
            ShardId resultShardId = new ShardId("index", "index-uuid", i);
            nodeLookups.add(Tuple.tuple(resultClusterAlias, resultNodeId));
            phaseResult.setSearchShardTarget(new SearchShardTarget(resultNodeId, resultShardId, resultClusterAlias, OriginalIndices.NONE));
            phaseResult.setShardIndex(i);
            phaseResults.consumeResult(phaseResult, () -> {});
        }
        return phaseResults;
    }

    public void testOnShardFailurePhaseDoneFailure() throws InterruptedException {
        final Index index = new Index("test", UUID.randomUUID().toString());
        final CountDownLatch latch = new CountDownLatch(1);
        final AtomicBoolean fail = new AtomicBoolean(true);

        final SearchShardIterator[] shards = IntStream.range(0, 5 + randomInt(10))
            .mapToObj(i -> new SearchShardIterator(null, new ShardId(index, i), List.of("n1", "n2", "n3"), null, null, null))
            .toArray(SearchShardIterator[]::new);

        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
        searchRequest.setMaxConcurrentShardRequests(1);

        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(shards.length);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
            searchRequest,
            queryResult,
            new ActionListener<SearchResponse>() {
                @Override
                public void onResponse(SearchResponse response) {

                }

                @Override
                public void onFailure(Exception e) {
                    if (fail.compareAndExchange(true, false)) {
                        try {
                            throw new RuntimeException("Simulated exception");
                        } finally {
                            executor.submit(() -> latch.countDown());
                        }
                    }
                }
            },
            false,
            true,
            new AtomicLong(),
            shards
        );
        action.run();
        assertTrue(latch.await(1, TimeUnit.SECONDS));

        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
        assertThat(searchResponse.getSuccessfulShards(), equalTo(0));
    }

    public void testOnShardSuccessPhaseDoneFailure() throws InterruptedException {
        final Index index = new Index("test", UUID.randomUUID().toString());
        final CountDownLatch latch = new CountDownLatch(1);
        final AtomicBoolean fail = new AtomicBoolean(true);

        final SearchShardIterator[] shards = IntStream.range(0, 5 + randomInt(10))
            .mapToObj(i -> new SearchShardIterator(null, new ShardId(index, i), List.of("n1", "n2", "n3"), null, null, null))
            .toArray(SearchShardIterator[]::new);

        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
        searchRequest.setMaxConcurrentShardRequests(1);

        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(shards.length);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
            searchRequest,
            queryResult,
            new ActionListener<SearchResponse>() {
                @Override
                public void onResponse(SearchResponse response) {
                    if (fail.compareAndExchange(true, false)) {
                        throw new RuntimeException("Simulated exception");
                    }
                }

                @Override
                public void onFailure(Exception e) {
                    executor.submit(() -> latch.countDown());
                }
            },
            false,
            false,
            new AtomicLong(),
            shards
        );
        action.run();
        assertTrue(latch.await(1, TimeUnit.SECONDS));

        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
        assertThat(searchResponse.getSuccessfulShards(), equalTo(shards.length));
    }

    public void testExecutePhaseOnShardFailure() throws InterruptedException {
        final Index index = new Index("test", UUID.randomUUID().toString());

        final SearchShardIterator[] shards = IntStream.range(0, 2 + randomInt(3))
            .mapToObj(i -> new SearchShardIterator(null, new ShardId(index, i), List.of("n1", "n2", "n3"), null, null, null))
            .toArray(SearchShardIterator[]::new);

        final AtomicBoolean fail = new AtomicBoolean(true);
        final CountDownLatch latch = new CountDownLatch(1);
        SearchRequest searchRequest = new SearchRequest().allowPartialSearchResults(true);
        searchRequest.setMaxConcurrentShardRequests(5);

        final ArraySearchPhaseResults<SearchPhaseResult> queryResult = new ArraySearchPhaseResults<>(shards.length);
        AbstractSearchAsyncAction<SearchPhaseResult> action = createAction(
            searchRequest,
            queryResult,
            new ActionListener<SearchResponse>() {
                @Override
                public void onResponse(SearchResponse response) {}

                @Override
                public void onFailure(Exception e) {
                    try {
                        // We end up here only when onPhaseDone() is called (causing NPE) and
                        // ending up in the onPhaseFailure() callback
                        if (fail.compareAndExchange(true, false)) {
                            assertThat(e, instanceOf(SearchPhaseExecutionException.class));
                            throw new RuntimeException("Simulated exception");
                        }
                    } finally {
                        executor.submit(() -> latch.countDown());
                    }
                }
            },
            false,
            false,
            new AtomicLong(),
            shards
        );
        action.run();
        assertTrue(latch.await(1, TimeUnit.SECONDS));

        InternalSearchResponse internalSearchResponse = InternalSearchResponse.empty();
        SearchResponse searchResponse = action.buildSearchResponse(internalSearchResponse, action.buildShardFailures(), null, null);
        assertSame(searchResponse.getAggregations(), internalSearchResponse.aggregations());
        assertSame(searchResponse.getSuggest(), internalSearchResponse.suggest());
        assertSame(searchResponse.getProfileResults(), internalSearchResponse.profile());
        assertSame(searchResponse.getHits(), internalSearchResponse.hits());
        assertThat(searchResponse.getSuccessfulShards(), equalTo(shards.length));
    }

    private static final class PhaseResult extends SearchPhaseResult {
        PhaseResult(ShardSearchContextId contextId) {
            this.contextId = contextId;
        }
    }
}