// Copyright 2017 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.buildeventservice;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Strings.isNullOrEmpty;
import static java.lang.String.format;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.devtools.build.lib.authandtls.AuthAndTLSOptions;
import com.google.devtools.build.lib.buildeventservice.client.BuildEventServiceClient;
import com.google.devtools.build.lib.buildeventstream.BuildEventArtifactUploader;
import com.google.devtools.build.lib.buildeventstream.BuildEventArtifactUploaderFactoryMap;
import com.google.devtools.build.lib.buildeventstream.BuildEventProtocolOptions;
import com.google.devtools.build.lib.buildeventstream.BuildEventTransport;
import com.google.devtools.build.lib.buildeventstream.transports.BuildEventStreamOptions;
import com.google.devtools.build.lib.buildeventstream.transports.BuildEventTransportFactory;
import com.google.devtools.build.lib.clock.Clock;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.events.Reporter;
import com.google.devtools.build.lib.runtime.BlazeModule;
import com.google.devtools.build.lib.runtime.BuildEventStreamer;
import com.google.devtools.build.lib.runtime.CommandEnvironment;
import com.google.devtools.build.lib.runtime.SynchronizedOutputStream;
import com.google.devtools.build.lib.util.AbruptExitException;
import com.google.devtools.build.lib.util.ExitCode;
import com.google.devtools.build.lib.util.io.OutErr;
import com.google.devtools.common.options.OptionsBase;
import com.google.devtools.common.options.OptionsParsingException;
import com.google.devtools.common.options.OptionsProvider;
import java.io.IOException;
import java.util.Set;
import java.util.logging.Logger;
import javax.annotation.Nullable;

/**
 * Module responsible for the Build Event Transport (BEP) and Build Event Service (BES)
 * functionality.
 */
public abstract class BuildEventServiceModule<T extends BuildEventServiceOptions>
    extends BlazeModule {

  private static final Logger logger = Logger.getLogger(BuildEventServiceModule.class.getName());

  private OutErr outErr;

  private Set<BuildEventTransport> transports = ImmutableSet.of();

  /** Whether an error in the Build Event Service upload causes the build to fail. */
  protected boolean errorsShouldFailTheBuild() {
    return true;
  }

  /** Report errors in the command line and possibly fail the build. */
  protected void reportError(
      EventHandler commandLineReporter,
      ModuleEnvironment moduleEnvironment,
      AbruptExitException exception) {
    commandLineReporter.handle(Event.error(exception.getMessage()));
    moduleEnvironment.exit(exception);
  }

  @Override
  public Iterable<Class<? extends OptionsBase>> getCommonCommandOptions() {
    return ImmutableList.of(
        optionsClass(),
        AuthAndTLSOptions.class,
        BuildEventStreamOptions.class,
        BuildEventProtocolOptions.class);
  }

  @Override
  public void beforeCommand(CommandEnvironment commandEnvironment) {
    // Reset to null in case afterCommand was not called.
    this.outErr = null;
    if (!whitelistedCommands().contains(commandEnvironment.getCommandName())) {
      return;
    }

    BuildEventStreamer streamer =
        tryCreateStreamer(
            commandEnvironment.getRuntime().getStartupOptionsProvider(),
            commandEnvironment.getOptions(),
            commandEnvironment.getReporter(),
            commandEnvironment.getBlazeModuleEnvironment(),
            commandEnvironment.getRuntime().getClock(),
            commandEnvironment.getRuntime().getBuildEventArtifactUploaderFactoryMap(),
            commandEnvironment.getReporter(),
            commandEnvironment.getBuildRequestId().toString(),
            commandEnvironment.getCommandId().toString(),
            commandEnvironment.getCommandName());
    if (streamer != null) {
      commandEnvironment.getReporter().addHandler(streamer);
      commandEnvironment.getEventBus().register(streamer);
      long bufferSize =
          commandEnvironment.getOptions().getOptions(optionsClass()).besOuterrBufferSize;

      final SynchronizedOutputStream out = new SynchronizedOutputStream(bufferSize);
      final SynchronizedOutputStream err = new SynchronizedOutputStream(bufferSize);
      this.outErr = OutErr.create(out, err);
      streamer.registerOutErrProvider(
          new BuildEventStreamer.OutErrProvider() {
            @Override
            public String getOut() {
              return out.readAndReset();
            }

            @Override
            public String getErr() {
              return err.readAndReset();
            }
          });
      err.registerStreamer(streamer);
      out.registerStreamer(streamer);
      logger.fine("BuildEventStreamer created and registered successfully.");
    }
  }

  @Override
  public OutErr getOutputListener() {
    return outErr;
  }

  @Override
  public void afterCommand() {
    this.outErr = null;
  }

  /** Returns {@code null} if no stream could be created. */
  @Nullable
  @VisibleForTesting
  BuildEventStreamer tryCreateStreamer(
      OptionsProvider startupOptionsProvider,
      OptionsProvider optionsProvider,
      EventHandler commandLineReporter,
      ModuleEnvironment moduleEnvironment,
      Clock clock,
      BuildEventArtifactUploaderFactoryMap buildEventArtifactUploaderFactoryMap,
      Reporter reporter,
      String buildRequestId,
      String invocationId,
      String commandName) {
    Preconditions.checkNotNull(buildEventArtifactUploaderFactoryMap);

    try {
      BuildEventTransport besTransport = null;
      try {
        besTransport =
            tryCreateBesTransport(
                buildRequestId,
                invocationId,
                commandName,
                moduleEnvironment,
                clock,
                buildEventArtifactUploaderFactoryMap,
                commandLineReporter,
                startupOptionsProvider,
                optionsProvider);
      } catch (Exception e) {
        reportError(
            commandLineReporter,
            moduleEnvironment,
            new AbruptExitException(
                "Failed while creating BuildEventTransport", ExitCode.PUBLISH_ERROR));
        return null;
      }

      ImmutableSet<BuildEventTransport> bepTransports =
          BuildEventTransportFactory.createFromOptions(
              optionsProvider, buildEventArtifactUploaderFactoryMap, moduleEnvironment::exit);

      ImmutableSet.Builder<BuildEventTransport> transportsBuilder =
          ImmutableSet.<BuildEventTransport>builder().addAll(bepTransports);
      if (besTransport != null) {
        transportsBuilder.add(besTransport);
      }

      transports = transportsBuilder.build();
      if (!transports.isEmpty()) {
        BuildEventStreamOptions buildEventStreamOptions =
            optionsProvider.getOptions(BuildEventStreamOptions.class);
        return new BuildEventStreamer(transports, reporter, buildEventStreamOptions);
      }
    } catch (Exception e) {
      reportError(
          commandLineReporter,
          moduleEnvironment,
          new AbruptExitException(ExitCode.LOCAL_ENVIRONMENTAL_ERROR, e));
    }
    return null;
  }

  @Nullable
  private BuildEventTransport tryCreateBesTransport(
      String buildRequestId,
      String invocationId,
      String commandName,
      ModuleEnvironment moduleEnvironment,
      Clock clock,
      BuildEventArtifactUploaderFactoryMap buildEventArtifactUploaderFactoryMap,
      EventHandler commandLineReporter,
      OptionsProvider startupOptionsProvider,
      OptionsProvider optionsProvider)
      throws IOException, OptionsParsingException {
    T besOptions =
        checkNotNull(
            optionsProvider.getOptions(optionsClass()), "Could not get BuildEventServiceOptions.");
    AuthAndTLSOptions authTlsOptions =
        checkNotNull(
            optionsProvider.getOptions(AuthAndTLSOptions.class),
            "Could not get AuthAndTLSOptions.");
    BuildEventProtocolOptions protocolOptions =
        checkNotNull(
            optionsProvider.getOptions(BuildEventProtocolOptions.class),
            "Could not get BuildEventProtocolOptions.");

    if (isNullOrEmpty(besOptions.besBackend)) {
      logger.fine("BuildEventServiceTransport is disabled.");
      return null;
    } else {
      logger.fine(
          format(
              "Will create BuildEventServiceTransport streaming to '%s'", besOptions.besBackend));

      final String besResultsUrl;
      if (!Strings.isNullOrEmpty(besOptions.besResultsUrl)) {
        besResultsUrl =
            besOptions.besResultsUrl.endsWith("/")
                ? besOptions.besResultsUrl + invocationId
                : besOptions.besResultsUrl + "/" + invocationId;
        commandLineReporter.handle(
            Event.info("Streaming Build Event Protocol to " + besResultsUrl));
      } else {
        besResultsUrl = null;
        commandLineReporter.handle(
            Event.info(
                format(
                    "Streaming Build Event Protocol to %s build_request_id: %s "
                        + "invocation_id: %s",
                    besOptions.besBackend, buildRequestId, invocationId)));
      }

      BuildEventServiceClient client = createBesClient(besOptions, authTlsOptions);
      BuildEventArtifactUploader artifactUploader =
          buildEventArtifactUploaderFactoryMap
              .select(protocolOptions.buildEventUploadStrategy)
              .create(optionsProvider);

      BuildEventTransport besTransport =
          new BuildEventServiceTransport(
              client,
              besOptions.besTimeout,
              besOptions.besLifecycleEvents,
              buildRequestId,
              invocationId,
              commandName,
              moduleEnvironment,
              clock,
              protocolOptions,
              commandLineReporter,
              besOptions.projectId,
              keywords(besOptions, startupOptionsProvider),
              besResultsUrl,
              artifactUploader,
              errorsShouldFailTheBuild());
      logger.fine("BuildEventServiceTransport was created successfully");
      return besTransport;
    }
  }

  @Override
  public void blazeShutdown() {
    for (BuildEventTransport transport : transports) {
      transport.closeNow();
    }
  }

  protected abstract Class<T> optionsClass();

  protected abstract BuildEventServiceClient createBesClient(
      T besOptions, AuthAndTLSOptions authAndTLSOptions)
      throws IOException, OptionsParsingException;

  protected abstract Set<String> whitelistedCommands();

  protected Set<String> keywords(T besOptions, @Nullable OptionsProvider startupOptionsProvider) {
    return besOptions
        .besKeywords
        .stream()
        .map(keyword -> "user_keyword=" + keyword)
        .collect(ImmutableSet.toImmutableSet());
  }
}