// Copyright 2018 The Bazel Authors. All rights reserved.
//
// Licensed 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.
package com.google.devtools.build.lib.remote;

import static com.google.common.truth.Truth.assertThat;
import static com.google.devtools.build.lib.remote.util.Utils.getFromFuture;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.spy;

import build.bazel.remote.execution.v2.ActionResult;
import build.bazel.remote.execution.v2.Digest;
import build.bazel.remote.execution.v2.RequestMetadata;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.util.concurrent.ListeningScheduledExecutorService;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.common.util.concurrent.SettableFuture;
import com.google.devtools.build.lib.actions.ActionInputHelper;
import com.google.devtools.build.lib.actions.ArtifactRoot;
import com.google.devtools.build.lib.actions.ArtifactRoot.RootType;
import com.google.devtools.build.lib.actions.ResourceSet;
import com.google.devtools.build.lib.actions.SimpleSpawn;
import com.google.devtools.build.lib.actions.Spawn;
import com.google.devtools.build.lib.clock.JavaClock;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.collect.nestedset.Order;
import com.google.devtools.build.lib.exec.util.FakeOwner;
import com.google.devtools.build.lib.remote.common.RemoteActionExecutionContext;
import com.google.devtools.build.lib.remote.merkletree.MerkleTree;
import com.google.devtools.build.lib.remote.options.RemoteOptions;
import com.google.devtools.build.lib.remote.util.DigestUtil;
import com.google.devtools.build.lib.remote.util.TracingMetadataUtils;
import com.google.devtools.build.lib.testutil.TestUtils;
import com.google.devtools.build.lib.util.io.FileOutErr;
import com.google.devtools.build.lib.vfs.DigestHashFunction;
import com.google.devtools.build.lib.vfs.FileSystem;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
import com.google.devtools.common.options.Options;
import com.google.protobuf.ByteString;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.mockito.MockitoAnnotations;

/** Tests for {@link RemoteCache}. */
@RunWith(JUnit4.class)
public class RemoteCacheTest {

  private RemoteActionExecutionContext context;
  private FileSystem fs;
  private Path execRoot;
  ArtifactRoot artifactRoot;
  private final DigestUtil digestUtil = new DigestUtil(DigestHashFunction.SHA256);
  private FakeActionInputFileCache fakeFileCache;

  private ListeningScheduledExecutorService retryService;

  @Before
  public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
    RequestMetadata metadata =
        TracingMetadataUtils.buildMetadata("none", "none", "action-id", null);
    Spawn spawn =
        new SimpleSpawn(
            new FakeOwner("foo", "bar", "//dummy:label"),
            /*arguments=*/ ImmutableList.of(),
            /*environment=*/ ImmutableMap.of(),
            /*executionInfo=*/ ImmutableMap.of(),
            /*inputs=*/ NestedSetBuilder.emptySet(Order.STABLE_ORDER),
            /*outputs=*/ ImmutableSet.of(),
            ResourceSet.ZERO);
    context = RemoteActionExecutionContext.create(spawn, metadata);
    fs = new InMemoryFileSystem(new JavaClock(), DigestHashFunction.SHA256);
    execRoot = fs.getPath("/execroot/main");
    execRoot.createDirectoryAndParents();
    fakeFileCache = new FakeActionInputFileCache(execRoot);
    artifactRoot = ArtifactRoot.asDerivedRoot(execRoot, RootType.Output, "outputs");
    artifactRoot.getRoot().asPath().createDirectoryAndParents();
    retryService = MoreExecutors.listeningDecorator(Executors.newScheduledThreadPool(1));
  }

  @After
  public void afterEverything() throws InterruptedException {
    retryService.shutdownNow();
    retryService.awaitTermination(TestUtils.WAIT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
  }

  @Test
  public void testDownloadEmptyBlobAndFile() throws Exception {
    // Test that downloading an empty BLOB/file does not try to perform a download.

    // arrange
    Path file = fs.getPath("/execroot/file");
    RemoteCache remoteCache = newRemoteCache();
    Digest emptyDigest = digestUtil.compute(new byte[0]);

    // act and assert
    assertThat(getFromFuture(remoteCache.downloadBlob(context, emptyDigest))).isEmpty();

    try (OutputStream out = file.getOutputStream()) {
      getFromFuture(remoteCache.downloadFile(context, file, emptyDigest));
    }
    assertThat(file.exists()).isTrue();
    assertThat(file.getFileSize()).isEqualTo(0);
  }

  @Test
  public void downloadOutErr_empty_doNotPerformDownload() throws Exception {
    // Test that downloading empty stdout/stderr does not try to perform a download.

    InMemoryRemoteCache remoteCache = newRemoteCache();
    Digest emptyDigest = digestUtil.compute(new byte[0]);
    ActionResult.Builder result = ActionResult.newBuilder();
    result.setStdoutDigest(emptyDigest);
    result.setStderrDigest(emptyDigest);

    RemoteCache.waitForBulkTransfer(
        remoteCache.downloadOutErr(
            context,
            result.build(),
            new FileOutErr(execRoot.getRelative("stdout"), execRoot.getRelative("stderr"))),
        true);

    assertThat(remoteCache.getNumSuccessfulDownloads()).isEqualTo(0);
    assertThat(remoteCache.getNumFailedDownloads()).isEqualTo(0);
  }

  @Test
  public void testDownloadFileWithSymlinkTemplate() throws Exception {
    // Test that when a symlink template is provided, we don't actually download files to disk.
    // Instead, a symbolic link should be created that points to a location where the file may
    // actually be found. That location could, for example, be backed by a FUSE file system that
    // exposes the Content Addressable Storage.

    // arrange
    final ConcurrentMap<Digest, byte[]> cas = new ConcurrentHashMap<>();

    Digest helloDigest = digestUtil.computeAsUtf8("hello-contents");
    cas.put(helloDigest, "hello-contents".getBytes(StandardCharsets.UTF_8));

    Path file = fs.getPath("/execroot/symlink-to-file");
    RemoteOptions options = Options.getDefaults(RemoteOptions.class);
    options.remoteDownloadSymlinkTemplate = "/home/alice/cas/{hash}-{size_bytes}";
    RemoteCache remoteCache = new InMemoryRemoteCache(cas, options, digestUtil);

    // act
    getFromFuture(remoteCache.downloadFile(context, file, helloDigest));

    // assert
    assertThat(file.isSymbolicLink()).isTrue();
    assertThat(file.readSymbolicLink())
        .isEqualTo(
            PathFragment.create(
                "/home/alice/cas/a378b939ad2e1d470a9a28b34b0e256b189e85cb236766edc1d46ec3b6ca82e5-14"));
  }

  @Test
  public void upload_emptyBlobAndFile_doNotPerformUpload() throws Exception {
    // Test that uploading an empty BLOB/file does not try to perform an upload.
    InMemoryRemoteCache remoteCache = newRemoteCache();
    Digest emptyDigest = fakeFileCache.createScratchInput(ActionInputHelper.fromPath("file"), "");
    Path file = execRoot.getRelative("file");

    getFromFuture(remoteCache.uploadBlob(context, emptyDigest, ByteString.EMPTY));
    assertThat(getFromFuture(remoteCache.findMissingDigests(context, ImmutableSet.of(emptyDigest))))
        .containsExactly(emptyDigest);

    getFromFuture(remoteCache.uploadFile(context, emptyDigest, file));
    assertThat(getFromFuture(remoteCache.findMissingDigests(context, ImmutableSet.of(emptyDigest))))
        .containsExactly(emptyDigest);
  }

  @Test
  public void ensureInputsPresent_interrupted_cancelInProgressUploadTasks() throws Exception {
    // arrange
    InMemoryRemoteCache remoteCache = spy(newRemoteCache());

    CountDownLatch findMissingDigestsCalled = new CountDownLatch(1);
    doAnswer(
            invocationOnMock -> {
              findMissingDigestsCalled.countDown();
              return SettableFuture.create();
            })
        .when(remoteCache)
        .findMissingDigests(any(), any());

    Path path = fs.getPath("/execroot/foo");
    FileSystemUtils.writeContentAsLatin1(path, "bar");
    SortedMap<PathFragment, Path> inputs = new TreeMap<>();
    inputs.put(PathFragment.create("foo"), path);
    MerkleTree merkleTree = MerkleTree.build(inputs, digestUtil);

    CountDownLatch ensureInputsPresentReturned = new CountDownLatch(1);
    Thread thread =
        new Thread(
            () -> {
              try {
                remoteCache.ensureInputsPresent(context, merkleTree, ImmutableMap.of(), false);
              } catch (IOException | InterruptedException ignored) {
                // ignored
              } finally {
                ensureInputsPresentReturned.countDown();
              }
            });

    // act
    thread.start();
    findMissingDigestsCalled.await();
    assertThat(remoteCache.casUploadCache.getInProgressTasks()).isNotEmpty();

    thread.interrupt();
    ensureInputsPresentReturned.await();

    // assert
    assertThat(remoteCache.casUploadCache.getInProgressTasks()).isEmpty();
  }

  private InMemoryRemoteCache newRemoteCache() {
    RemoteOptions options = Options.getDefaults(RemoteOptions.class);
    return new InMemoryRemoteCache(options, digestUtil);
  }
}