// 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.query2;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.util.concurrent.AsyncFunction;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.cmdline.TargetParsingException;
import com.google.devtools.build.lib.cmdline.TargetPattern;
import com.google.devtools.build.lib.events.ExtendedEventHandler;
import com.google.devtools.build.lib.events.Reporter;
import com.google.devtools.build.lib.packages.RuleTransitionFactory;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.pkgcache.PackageManager;
import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
import com.google.devtools.build.lib.query2.engine.Callback;
import com.google.devtools.build.lib.query2.engine.KeyExtractor;
import com.google.devtools.build.lib.query2.engine.QueryEnvironment;
import com.google.devtools.build.lib.query2.engine.QueryException;
import com.google.devtools.build.lib.query2.engine.QueryExpression;
import com.google.devtools.build.lib.query2.engine.QueryUtil.ThreadSafeMutableKeyExtractorBackedSetImpl;
import com.google.devtools.build.lib.query2.output.AspectResolver;
import com.google.devtools.build.lib.query2.output.CqueryOptions;
import com.google.devtools.build.lib.rules.AliasConfiguredTarget;
import com.google.devtools.build.lib.skyframe.BuildConfigurationValue;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetKey;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetValue;
import com.google.devtools.build.lib.skyframe.SkyframeExecutor;
import com.google.devtools.build.skyframe.SkyKey;
import com.google.devtools.build.skyframe.WalkableGraph;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.function.Supplier;
import javax.annotation.Nullable;

/**
 * {@link QueryEnvironment} that runs queries over the configured target (analysis) graph.
 *
 * <p>There is currently a limited way to specify a configuration in the query syntax via {@link
 * ConfigFunction}. This currently still limits the user to choosing the 'target', 'host', or null
 * configurations. It shouldn't be terribly difficult to expand this with {@link
 * OptionsDiffForReconstruction} to handle fully customizable configurations if the need arises in
 * the future.
 *
 * <p>Aspects are also not supported, but probably should be in some fashion.
 */
public class ConfiguredTargetQueryEnvironment
    extends PostAnalysisQueryEnvironment<ConfiguredTarget> {
  /** Common query functions and cquery specific functions. */
  public static final ImmutableList<QueryFunction> FUNCTIONS = populateFunctions();
  /** Cquery specific functions. */
  public static final ImmutableList<QueryFunction> CQUERY_FUNCTIONS = getCqueryFunctions();

  private CqueryOptions cqueryOptions;

  private final KeyExtractor<ConfiguredTarget, ConfiguredTargetKey> configuredTargetKeyExtractor;

  @Override
  protected KeyExtractor<ConfiguredTarget, ConfiguredTargetKey> getConfiguredTargetKeyExtractor() {
    return configuredTargetKeyExtractor;
  }

  public ConfiguredTargetQueryEnvironment(
      boolean keepGoing,
      ExtendedEventHandler eventHandler,
      Iterable<QueryFunction> extraFunctions,
      BuildConfiguration defaultTargetConfiguration,
      BuildConfiguration hostConfiguration,
      String parserPrefix,
      PathPackageLocator pkgPath,
      Supplier<WalkableGraph> walkableGraphSupplier,
      Set<Setting> settings) {
    super(
        keepGoing,
        eventHandler,
        extraFunctions,
        defaultTargetConfiguration,
        hostConfiguration,
        parserPrefix,
        pkgPath,
        walkableGraphSupplier,
        settings,
        new ConfiguredTargetAccessor(walkableGraphSupplier.get()));
    this.configuredTargetKeyExtractor =
        element -> {
          try {
            return ConfiguredTargetKey.of(
                element,
                element.getConfigurationKey() == null
                    ? null
                    : ((BuildConfigurationValue) graph.getValue(element.getConfigurationKey()))
                        .getConfiguration());
          } catch (InterruptedException e) {
            throw new IllegalStateException("Interruption unexpected in configured query");
          }
        };
  }

  public ConfiguredTargetQueryEnvironment(
      boolean keepGoing,
      ExtendedEventHandler eventHandler,
      Iterable<QueryFunction> extraFunctions,
      BuildConfiguration defaultTargetConfiguration,
      BuildConfiguration hostConfiguration,
      String parserPrefix,
      PathPackageLocator pkgPath,
      Supplier<WalkableGraph> walkableGraphSupplier,
      CqueryOptions cqueryOptions) {
    this(keepGoing, eventHandler, extraFunctions, defaultTargetConfiguration, hostConfiguration,
        parserPrefix, pkgPath, walkableGraphSupplier, cqueryOptions.toSettings());
    this.cqueryOptions = cqueryOptions;
  }

  private static ImmutableList<QueryFunction> populateFunctions() {
    return new ImmutableList.Builder<QueryFunction>()
        .addAll(QueryEnvironment.DEFAULT_QUERY_FUNCTIONS)
        .addAll(getCqueryFunctions())
        .build();
  }

  private static ImmutableList<QueryFunction> getCqueryFunctions() {
    return ImmutableList.of(new ConfigFunction());
  }

  @Override
  public ImmutableList<CqueryThreadsafeCallback> getDefaultOutputFormatters(
      TargetAccessor<ConfiguredTarget> accessor,
      Reporter reporter,
      SkyframeExecutor skyframeExecutor,
      BuildConfiguration hostConfiguration,
      @Nullable RuleTransitionFactory trimmingTransitionFactory,
      PackageManager packageManager) {
    AspectResolver aspectResolver =
        cqueryOptions.aspectDeps.createResolver(packageManager, reporter);
    OutputStream out = reporter.getOutErr().getOutputStream();
    return new ImmutableList.Builder<CqueryThreadsafeCallback>()
        .add(
            new LabelAndConfigurationOutputFormatterCallback(
                reporter, cqueryOptions, out, skyframeExecutor, accessor))
        .add(
            new TransitionsOutputFormatterCallback(
                reporter,
                cqueryOptions,
                out,
                skyframeExecutor,
                accessor,
                hostConfiguration,
                trimmingTransitionFactory))
        .add(
            new ProtoOutputFormatterCallback(
                reporter, cqueryOptions, out, skyframeExecutor, accessor, aspectResolver))
        .build();
  }

  public String getOutputFormat() {
    return cqueryOptions.outputFormat;
  }

  @Override
  public QueryTaskFuture<Void> getTargetsMatchingPattern(
      QueryExpression owner, String pattern, Callback<ConfiguredTarget> callback) {
    TargetPattern patternToEval;
    try {
      patternToEval = getPattern(pattern);
    } catch (TargetParsingException tpe) {
      try {
        reportBuildFileError(owner, tpe.getMessage());
      } catch (QueryException qe) {
        return immediateFailedFuture(qe);
      }
      return immediateSuccessfulFuture(null);
    }
    AsyncFunction<TargetParsingException, Void> reportBuildFileErrorAsyncFunction =
        exn -> {
          reportBuildFileError(owner, exn.getMessage());
          return Futures.immediateFuture(null);
        };
    return QueryTaskFutureImpl.ofDelegate(
        Futures.catchingAsync(
            patternToEval.evalAdaptedForAsync(
                resolver,
                ImmutableSet.of(),
                ImmutableSet.of(),
                (Callback<Target>)
                    partialResult -> {
                      List<ConfiguredTarget> transformedResult = new ArrayList<>();
                      for (Target target : partialResult) {
                        ConfiguredTarget configuredTarget = getConfiguredTarget(target.getLabel());
                        if (configuredTarget != null) {
                          transformedResult.add(configuredTarget);
                        }
                      }
                      callback.process(transformedResult);
                    },
                QueryException.class),
            TargetParsingException.class,
            reportBuildFileErrorAsyncFunction,
            MoreExecutors.directExecutor()));
  }

  private ConfiguredTarget getConfiguredTarget(Label label) throws InterruptedException {
    // Try with target configuration.
    ConfiguredTarget configuredTarget = getTargetConfiguredTarget(label);
    if (configuredTarget != null) {
      return configuredTarget;
    }
    // Try with host configuration (even when --nohost_deps is set in the case that top-level
    // targets are configured in the host configuration so we are doing a host-configuration-only
    // query).
    configuredTarget = getHostConfiguredTarget(label);
    if (configuredTarget != null) {
      return configuredTarget;
    }
    // Last chance: source file.
    return getNullConfiguredTarget(label);
  }

  @Override
  @Nullable
  protected ConfiguredTarget getValueFromKey(SkyKey key) throws InterruptedException {
    ConfiguredTargetValue value = getConfiguredTargetValue(key);
    return value == null ? null : value.getConfiguredTarget();
  }

  /**
   * Processes the targets in {@code targets} with the requested {@code configuration}
   *
   * @param pattern the original pattern that {@code targets} were parsed from. Used for error
   *     message.
   * @param targets the set of {@link ConfiguredTarget}s whose labels represent the targets being
   *     requested.
   * @param configuration the configuration to request {@code targets} in.
   * @param callback the callback to receive the results of this method.
   * @return {@link QueryTaskCallable} that returns the correctly configured targets.
   */
  QueryTaskCallable<Void> getConfiguredTargets(
      String pattern,
      ThreadSafeMutableSet<ConfiguredTarget> targets,
      String configuration,
      Callback<ConfiguredTarget> callback) {
    return new QueryTaskCallable<Void>() {
      @Override
      public Void call() throws QueryException, InterruptedException {
        List<ConfiguredTarget> transformedResult = new ArrayList<>();
        for (ConfiguredTarget target : targets) {
          Label label = getCorrectLabel(target);
          ConfiguredTarget configuredTarget;
          switch (configuration) {
            case "\'host\'":
              configuredTarget = getHostConfiguredTarget(label);
              break;
            case "\'target\'":
              configuredTarget = getTargetConfiguredTarget(label);
              break;
            case "\'null\'":
              configuredTarget = getNullConfiguredTarget(label);
              break;
            default:
              throw new QueryException(
                  "the second argument of the config function must be 'target', 'host', or 'null'");
          }
          if (configuredTarget != null) {
            transformedResult.add(configuredTarget);
          }
        }
        if (transformedResult.isEmpty()) {
          throw new QueryException(
              "No target (in) "
                  + pattern
                  + " could be found in the "
                  + configuration
                  + " configuration");
        }
        callback.process(transformedResult);
        return null;
      }
    };
  }

  /**
   * This method has to exist because {@link AliasConfiguredTarget#getLabel()} returns the label of
   * the "actual" target instead of the alias target. Grr.
   */
  @Override
  public Label getCorrectLabel(ConfiguredTarget target) {
    if (target instanceof AliasConfiguredTarget) {
      return ((AliasConfiguredTarget) target).getOriginalLabel();
    }
    return target.getLabel();
  }

  @Nullable
  @Override
  protected ConfiguredTarget getHostConfiguredTarget(Label label) throws InterruptedException {
    return getValueFromKey(ConfiguredTargetValue.key(label, hostConfiguration));
  }

  @Nullable
  @Override
  protected ConfiguredTarget getTargetConfiguredTarget(Label label) throws InterruptedException {
    return getValueFromKey(ConfiguredTargetValue.key(label, defaultTargetConfiguration));
  }

  @Nullable
  @Override
  protected ConfiguredTarget getNullConfiguredTarget(Label label) throws InterruptedException {
    return getValueFromKey(ConfiguredTargetValue.key(label, null));
  }

  @Nullable
  @Override
  protected BuildConfiguration getConfiguration(ConfiguredTarget target) {
    try {
      return target.getConfigurationKey() == null
          ? null
          : ((BuildConfigurationValue) graph.getValue(target.getConfigurationKey()))
              .getConfiguration();
    } catch (InterruptedException e) {
      throw new IllegalStateException("Unexpected interruption during configured target query");
    }
  }

  @Override
  protected ConfiguredTargetKey getSkyKey(ConfiguredTarget target) {
    return ConfiguredTargetKey.of(target, getConfiguration(target));
  }

  @Override
  public ThreadSafeMutableSet<ConfiguredTarget> createThreadSafeMutableSet() {
    return new ThreadSafeMutableKeyExtractorBackedSetImpl<>(
        configuredTargetKeyExtractor,
        ConfiguredTarget.class,
        SkyQueryEnvironment.DEFAULT_THREAD_COUNT);
  }
}