// 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.analysis.util;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Streams;
import com.google.common.eventbus.EventBus;
import com.google.devtools.build.lib.actions.ArtifactFactory;
import com.google.devtools.build.lib.actions.PackageRoots;
import com.google.devtools.build.lib.analysis.AnalysisEnvironment;
import com.google.devtools.build.lib.analysis.AnalysisOptions;
import com.google.devtools.build.lib.analysis.AnalysisResult;
import com.google.devtools.build.lib.analysis.AnalysisUtils;
import com.google.devtools.build.lib.analysis.BlazeDirectories;
import com.google.devtools.build.lib.analysis.BuildView;
import com.google.devtools.build.lib.analysis.CachingAnalysisEnvironment;
import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.Dependency;
import com.google.devtools.build.lib.analysis.DependencyResolver;
import com.google.devtools.build.lib.analysis.DependencyResolver.InconsistentAspectOrderException;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.TargetAndConfiguration;
import com.google.devtools.build.lib.analysis.ToolchainContext;
import com.google.devtools.build.lib.analysis.ToolchainResolver;
import com.google.devtools.build.lib.analysis.ToolchainResolver.UnloadedToolchainContext;
import com.google.devtools.build.lib.analysis.TopLevelArtifactContext;
import com.google.devtools.build.lib.analysis.ViewCreationFailedException;
import com.google.devtools.build.lib.analysis.WorkspaceStatusAction;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.analysis.config.BuildConfigurationCollection;
import com.google.devtools.build.lib.analysis.config.BuildOptions;
import com.google.devtools.build.lib.analysis.config.ConfigMatchingProvider;
import com.google.devtools.build.lib.analysis.config.ConfigurationResolver;
import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
import com.google.devtools.build.lib.analysis.config.TransitionResolver;
import com.google.devtools.build.lib.analysis.config.transitions.ConfigurationTransition;
import com.google.devtools.build.lib.analysis.config.transitions.NoTransition;
import com.google.devtools.build.lib.analysis.skylark.StarlarkTransition.TransitionException;
import com.google.devtools.build.lib.analysis.test.CoverageReportActionFactory;
import com.google.devtools.build.lib.causes.Cause;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.collect.nestedset.Order;
import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadCompatible;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.events.EventHandler;
import com.google.devtools.build.lib.events.ExtendedEventHandler;
import com.google.devtools.build.lib.events.StoredEventHandler;
import com.google.devtools.build.lib.packages.Attribute;
import com.google.devtools.build.lib.packages.BuildType;
import com.google.devtools.build.lib.packages.NoSuchPackageException;
import com.google.devtools.build.lib.packages.NoSuchTargetException;
import com.google.devtools.build.lib.packages.PackageSpecification;
import com.google.devtools.build.lib.packages.PackageSpecification.PackageGroupContents;
import com.google.devtools.build.lib.packages.RawAttributeMapper;
import com.google.devtools.build.lib.packages.Rule;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.skyframe.AspectValue;
import com.google.devtools.build.lib.skyframe.BuildConfigurationValue;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetAndData;
import com.google.devtools.build.lib.skyframe.ConfiguredTargetKey;
import com.google.devtools.build.lib.skyframe.SkyFunctionEnvironmentForTesting;
import com.google.devtools.build.lib.skyframe.SkyframeBuildView;
import com.google.devtools.build.lib.skyframe.SkyframeExecutor;
import com.google.devtools.build.lib.skyframe.TargetPatternPhaseValue;
import com.google.devtools.build.lib.skyframe.ToolchainException;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.util.OrderedSetMultimap;
import com.google.devtools.build.skyframe.SkyKey;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;

/**
 * A util class that contains all the helper stuff previously in BuildView that only exists to give
 * tests access to Skyframe internals. The code largely predates the introduction of Skyframe, and
 * mostly exists to avoid having to rewrite our tests to work with Skyframe natively.
 */
public class BuildViewForTesting {
  private final BuildView buildView;
  private final SkyframeExecutor skyframeExecutor;
  private final SkyframeBuildView skyframeBuildView;

  private final ConfiguredRuleClassProvider ruleClassProvider;

  public BuildViewForTesting(
      BlazeDirectories directories,
      ConfiguredRuleClassProvider ruleClassProvider,
      SkyframeExecutor skyframeExecutor,
      CoverageReportActionFactory coverageReportActionFactory) {
    this.buildView =
        new BuildView(
            directories,
            ruleClassProvider,
            skyframeExecutor,
            coverageReportActionFactory);
    this.ruleClassProvider = ruleClassProvider;
    this.skyframeExecutor = Preconditions.checkNotNull(skyframeExecutor);
    this.skyframeBuildView = skyframeExecutor.getSkyframeBuildView();
  }

  @VisibleForTesting
  public Set<SkyKey> getSkyframeEvaluatedTargetKeysForTesting() {
    return skyframeBuildView.getEvaluatedTargetKeys();
  }

  /**
   * Returns whether the given configured target has errors.
   */
  @VisibleForTesting
  public boolean hasErrors(ConfiguredTarget configuredTarget) {
    return configuredTarget == null;
  }

  @ThreadCompatible
  public AnalysisResult update(
      TargetPatternPhaseValue loadingResult,
      BuildOptions targetOptions,
      Set<String> multiCpu,
      List<String> aspects,
      AnalysisOptions viewOptions,
      boolean keepGoing,
      int loadingPhaseThreads,
      TopLevelArtifactContext topLevelOptions,
      ExtendedEventHandler eventHandler,
      EventBus eventBus)
      throws ViewCreationFailedException, InterruptedException, InvalidConfigurationException {
    return buildView.update(
        loadingResult,
        targetOptions,
        multiCpu,
        aspects,
        viewOptions,
        keepGoing,
        loadingPhaseThreads,
        topLevelOptions,
        eventHandler,
        eventBus);
  }

  @VisibleForTesting
  WorkspaceStatusAction getLastWorkspaceBuildInfoActionForTesting() throws InterruptedException {
    return skyframeExecutor.getLastWorkspaceStatusAction();
  }

  /** Sets the configurations. Not thread-safe. DO NOT CALL except from tests! */
  @VisibleForTesting
  public void setConfigurationsForTesting(
      EventHandler eventHandler, BuildConfigurationCollection configurations) {
    skyframeBuildView.setConfigurations(
        eventHandler, configurations, /* maxDifferencesToShow */ -1);
  }

  public ArtifactFactory getArtifactFactory() {
    return skyframeBuildView.getArtifactFactory();
  }

  /**
   * Gets a configuration for the given target.
   *
   * <p>If {@link BuildConfiguration.Options#trimConfigurations()} is true, the configuration only
   * includes the fragments needed by the fragment and its transitive closure. Else unconditionally
   * includes all fragments.
   *
   * @throws TransitionException if there was a problem resolving Starlark-defined configuration
   *     transitions.
   */
  @VisibleForTesting
  public BuildConfiguration getConfigurationForTesting(
      Target target, BuildConfiguration config, ExtendedEventHandler eventHandler)
      throws TransitionException {
    List<TargetAndConfiguration> node =
        ImmutableList.<TargetAndConfiguration>of(new TargetAndConfiguration(target, config));
    LinkedHashSet<TargetAndConfiguration> configs =
        ConfigurationResolver.getConfigurationsFromExecutor(
            node,
            AnalysisUtils.targetsToDeps(
                new LinkedHashSet<TargetAndConfiguration>(node), ruleClassProvider),
            eventHandler,
            skyframeExecutor);
    return configs.iterator().next().getConfiguration();
  }

  /**
   * Sets the possible artifact roots in the artifact factory. This allows the factory to resolve
   * paths with unknown roots to artifacts.
   */
  @VisibleForTesting // for BuildViewTestCase
  public void setArtifactRoots(PackageRoots packageRoots) {
    getArtifactFactory().setPackageRoots(packageRoots.getPackageRootLookup());
  }

  @VisibleForTesting
  public Collection<ConfiguredTarget> getDirectPrerequisitesForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget ct,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException {
    return Collections2.transform(
        getConfiguredTargetAndDataDirectPrerequisitesForTesting(eventHandler, ct, configurations),
        ConfiguredTargetAndData::getConfiguredTarget);
  }

  // TODO(janakr): pass the configuration in as a parameter here and above.
  private Collection<ConfiguredTargetAndData>
  getConfiguredTargetAndDataDirectPrerequisitesForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget ct,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException {
    return getConfiguredTargetAndDataDirectPrerequisitesForTesting(
        eventHandler, ct, ct.getConfigurationKey(), configurations);
  }

  @VisibleForTesting
  public Collection<ConfiguredTargetAndData>
  getConfiguredTargetAndDataDirectPrerequisitesForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTargetAndData ct,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException {
    return getConfiguredTargetAndDataDirectPrerequisitesForTesting(
        eventHandler,
        ct.getConfiguredTarget(),
        ct.getConfiguredTarget().getConfigurationKey(),
        configurations);
  }

  private Collection<ConfiguredTargetAndData>
  getConfiguredTargetAndDataDirectPrerequisitesForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget ct,
      BuildConfigurationValue.Key configuration,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException {
    ImmutableList<ConfiguredTargetAndData> configuredTargetsForTesting;
    try {
      configuredTargetsForTesting =
          skyframeExecutor.getConfiguredTargetsForTesting(
              eventHandler,
              configuration,
              ImmutableSet.copyOf(
                  getDirectPrerequisiteDependenciesForTesting(
                          eventHandler, ct, configurations, /*toolchainLabels=*/ ImmutableSet.of())
                      .values()));
    } catch (TransitionException e) {
      throw new InvalidConfigurationException(e);
    }
    return configuredTargetsForTesting;
  }

  @VisibleForTesting
  public OrderedSetMultimap<Attribute, Dependency> getDirectPrerequisiteDependenciesForTesting(
      final ExtendedEventHandler eventHandler,
      final ConfiguredTarget ct,
      BuildConfigurationCollection configurations,
      ImmutableSet<Label> toolchainLabels)
      throws EvalException, InterruptedException, InconsistentAspectOrderException {

    Target target = null;
    try {
      target = skyframeExecutor.getPackageManager().getTarget(eventHandler, ct.getLabel());
    } catch (NoSuchPackageException | NoSuchTargetException | InterruptedException e) {
      eventHandler.handle(
          Event.error("Failed to get target from package during prerequisite analysis." + e));
      return OrderedSetMultimap.create();
    }

    if (!(target instanceof Rule)) {
      return OrderedSetMultimap.create();
    }

    class SilentDependencyResolver extends DependencyResolver {
      private SilentDependencyResolver() {
      }

      @Override
      protected void invalidPackageGroupReferenceHook(TargetAndConfiguration node, Label label) {
        throw new RuntimeException("bad package group on " + label + " during testing unexpected");
      }

      @Override
      protected Map<Label, Target> getTargets(
          Collection<Label> labels, Target fromTarget, NestedSetBuilder<Cause> rootCauses) {
        return Streams.stream(labels)
            .distinct()
            .collect(
                Collectors.toMap(
                    Function.identity(),
                    label -> {
                      try {
                        return skyframeExecutor.getPackageManager().getTarget(eventHandler, label);
                      } catch (NoSuchPackageException
                          | NoSuchTargetException
                          | InterruptedException e) {
                        throw new IllegalStateException(e);
                      }
                    }));
      }
    }

    DependencyResolver dependencyResolver = new SilentDependencyResolver();
    TargetAndConfiguration ctgNode =
        new TargetAndConfiguration(
            target, skyframeExecutor.getConfiguration(eventHandler, ct.getConfigurationKey()));
    OrderedSetMultimap<Attribute, Dependency> dependentNodeMap;
    try {
      dependentNodeMap =
          dependencyResolver.dependentNodeMap(
              ctgNode,
              configurations.getHostConfiguration(),
              /*aspect=*/ null,
              getConfigurableAttributeKeysForTesting(eventHandler, ctgNode),
              toolchainLabels,
              ruleClassProvider.getTrimmingTransitionFactory());
    } catch (TransitionException e) {
      eventHandler.handle(
          Event.error("Encountered errors while applying Starlark-defined transition: " + e));
      return OrderedSetMultimap.create();
    }
    return dependentNodeMap;
  }

  /**
   * Returns ConfigMatchingProvider instances corresponding to the configurable attribute keys
   * present in this rule's attributes.
   */
  private ImmutableMap<Label, ConfigMatchingProvider> getConfigurableAttributeKeysForTesting(
      ExtendedEventHandler eventHandler, TargetAndConfiguration ctg) throws TransitionException {
    if (!(ctg.getTarget() instanceof Rule)) {
      return ImmutableMap.of();
    }
    Rule rule = (Rule) ctg.getTarget();
    Map<Label, ConfigMatchingProvider> keys = new LinkedHashMap<>();
    RawAttributeMapper mapper = RawAttributeMapper.of(rule);
    for (Attribute attribute : rule.getAttributes()) {
      for (Label label : mapper.getConfigurabilityKeys(attribute.getName(), attribute.getType())) {
        if (BuildType.Selector.isReservedLabel(label)) {
          continue;
        }
        ConfiguredTarget ct = getConfiguredTargetForTesting(
            eventHandler, label, ctg.getConfiguration());
        keys.put(label, Preconditions.checkNotNull(ct.getProvider(ConfigMatchingProvider.class)));
      }
    }
    return ImmutableMap.copyOf(keys);
  }

  private OrderedSetMultimap<Attribute, ConfiguredTargetAndData> getPrerequisiteMapForTesting(
      final ExtendedEventHandler eventHandler,
      ConfiguredTarget target,
      BuildConfigurationCollection configurations,
      ImmutableSet<Label> toolchainLabels)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException {
    OrderedSetMultimap<Attribute, Dependency> depNodeNames =
        getDirectPrerequisiteDependenciesForTesting(
            eventHandler, target, configurations, toolchainLabels);

    ImmutableMultimap<Dependency, ConfiguredTargetAndData> cts;
    try {
      cts =
          skyframeExecutor.getConfiguredTargetMapForTesting(
              eventHandler,
              target.getConfigurationKey(),
              ImmutableSet.copyOf(depNodeNames.values()));
    } catch (TransitionException e) {
      throw new InvalidConfigurationException(e);
    }

    OrderedSetMultimap<Attribute, ConfiguredTargetAndData> result = OrderedSetMultimap.create();
    for (Map.Entry<Attribute, Dependency> entry : depNodeNames.entries()) {
      result.putAll(entry.getKey(), cts.get(entry.getValue()));
    }
    return result;
  }

  private ConfigurationTransition getTopLevelTransitionForTarget(
      Label label, BuildConfiguration config, ExtendedEventHandler handler) {
    Target target;
    try {
      target = skyframeExecutor.getPackageManager().getTarget(handler, label);
    } catch (NoSuchPackageException | NoSuchTargetException e) {
      return NoTransition.INSTANCE;
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      throw new AssertionError("Configuration of " + label + " interrupted");
    }
    // Return early if a rule target is in error. We don't want whatever caused the rule error to
    // also cause problems in computing the transition (e.g. an unchecked exception).
    if (target instanceof Rule && ((Rule) target).containsErrors()) {
      return null;
    }
    return TransitionResolver.evaluateTopLevelTransition(
        new TargetAndConfiguration(target, config),
        ruleClassProvider.getTrimmingTransitionFactory());
  }

  /**
   * Returns a configured target for the specified target and configuration. If the target in
   * question has a top-level rule class transition, that transition is applied in the returned
   * ConfiguredTarget.
   *
   * <p>Returns {@code null} if something goes wrong.
   */
  @VisibleForTesting
  public ConfiguredTarget getConfiguredTargetForTesting(
      ExtendedEventHandler eventHandler, Label label, BuildConfiguration config) {
    ConfigurationTransition transition =
        getTopLevelTransitionForTarget(label, config, eventHandler);
    if (transition == null) {
      return null;
    }
    try {
      return skyframeExecutor.getConfiguredTargetForTesting(
          eventHandler, label, config, transition);
    } catch (TransitionException e) {
      return null;
    }
  }

  @VisibleForTesting
  public ConfiguredTargetAndData getConfiguredTargetAndDataForTesting(
      ExtendedEventHandler eventHandler, Label label, BuildConfiguration config) {
    ConfigurationTransition transition =
        getTopLevelTransitionForTarget(label, config, eventHandler);
    if (transition == null) {
      return null;
    }
    try {
      return skyframeExecutor.getConfiguredTargetAndDataForTesting(
          eventHandler, label, config, transition);
    } catch (TransitionException e) {
      return null;
    }
  }

  /**
   * Returns a RuleContext which is the same as the original RuleContext of the target parameter.
   */
  @VisibleForTesting
  public RuleContext getRuleContextForTesting(
      ConfiguredTarget target,
      StoredEventHandler eventHandler,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException, ToolchainException {
    BuildConfiguration targetConfig =
        skyframeExecutor.getConfiguration(eventHandler, target.getConfigurationKey());
    CachingAnalysisEnvironment env =
        new CachingAnalysisEnvironment(
            getArtifactFactory(),
            skyframeExecutor.getActionKeyContext(),
            ConfiguredTargetKey.of(target.getLabel(), targetConfig),
            /*isSystemEnv=*/ false,
            targetConfig.extendedSanityChecks(),
            eventHandler,
            /*env=*/ null);
    return getRuleContextForTesting(eventHandler, target, env, configurations);
  }

  /**
   * Creates and returns a rule context that is equivalent to the one that was used to create the
   * given configured target.
   */
  @VisibleForTesting
  public RuleContext getRuleContextForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget configuredTarget,
      AnalysisEnvironment env,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException, ToolchainException {
    BuildConfiguration targetConfig =
        skyframeExecutor.getConfiguration(eventHandler, configuredTarget.getConfigurationKey());
    Target target = null;
    try {
      target =
          skyframeExecutor.getPackageManager().getTarget(eventHandler, configuredTarget.getLabel());
    } catch (NoSuchPackageException | NoSuchTargetException e) {
      eventHandler.handle(
          Event.error("Failed to get target when trying to get rule context for testing"));
      throw new IllegalStateException(e);
    }
    ImmutableSet<Label> requiredToolchains =
        target.getAssociatedRule().getRuleClassObject().getRequiredToolchains();
    SkyFunctionEnvironmentForTesting skyfunctionEnvironment =
        skyframeExecutor.getSkyFunctionEnvironmentForTesting(eventHandler);
    UnloadedToolchainContext unloadedToolchainContext =
        new ToolchainResolver(skyfunctionEnvironment, BuildConfigurationValue.key(targetConfig))
            .setRequiredToolchainTypes(requiredToolchains)
            .resolve();

    OrderedSetMultimap<Attribute, ConfiguredTargetAndData> prerequisiteMap =
        getPrerequisiteMapForTesting(
            eventHandler,
            configuredTarget,
            configurations,
            unloadedToolchainContext.resolvedToolchainLabels());
    ToolchainContext toolchainContext = unloadedToolchainContext.load(prerequisiteMap);

    return new RuleContext.Builder(
        env,
        target,
        ImmutableList.of(),
        targetConfig,
        configurations.getHostConfiguration(),
        ruleClassProvider.getPrerequisiteValidator(),
        target.getAssociatedRule().getRuleClassObject().getConfigurationFragmentPolicy())
        .setVisibility(
            NestedSetBuilder.create(
                Order.STABLE_ORDER,
                PackageGroupContents.create(ImmutableList.of(PackageSpecification.everything()))))
        .setPrerequisites(
            getPrerequisiteMapForTesting(
                eventHandler,
                configuredTarget,
                configurations,
                unloadedToolchainContext.resolvedToolchainLabels()))
        .setConfigConditions(ImmutableMap.<Label, ConfigMatchingProvider>of())
        .setUniversalFragments(ruleClassProvider.getUniversalFragments())
        .setToolchainContext(toolchainContext)
        .setConstraintSemantics(ruleClassProvider.getConstraintSemantics())
        .build();
  }

  /**
   * For a configured target dependentTarget, returns the desired configured target that is depended
   * upon. Useful for obtaining the a target with aspects required by the dependent.
   */
  @VisibleForTesting
  public ConfiguredTarget getPrerequisiteConfiguredTargetForTesting(
      ExtendedEventHandler eventHandler,
      ConfiguredTarget dependentTarget,
      Label desiredTarget,
      BuildConfigurationCollection configurations)
      throws EvalException, InvalidConfigurationException, InterruptedException,
      InconsistentAspectOrderException {
    Collection<ConfiguredTargetAndData> configuredTargets =
        getPrerequisiteMapForTesting(
            eventHandler,
            dependentTarget,
            configurations,
            /*toolchainLabels=*/ ImmutableSet.of())
            .values();
    for (ConfiguredTargetAndData ct : configuredTargets) {
      if (ct.getTarget().getLabel().equals(desiredTarget)) {
        return ct.getConfiguredTarget();
      }
    }
    return null;
  }

  /** Clears the analysis cache as in --discard_analysis_cache. */
  public void clearAnalysisCache(
      Collection<ConfiguredTarget> topLevelTargets, Collection<AspectValue> topLevelAspects) {
    skyframeBuildView.clearAnalysisCache(topLevelTargets, topLevelAspects);
  }
}