// Copyright 2014 Google Inc. 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.rules.cpp;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Functions;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.ActionOwner;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.Root;
import com.google.devtools.build.lib.analysis.AnalysisEnvironment;
import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.rules.cpp.CcToolchainFeatures.FeatureConfiguration;
import com.google.devtools.build.lib.rules.cpp.CppCompileAction.DotdFile;
import com.google.devtools.build.lib.rules.cpp.CppCompileAction.IncludeResolver;
import com.google.devtools.build.lib.syntax.Label;
import com.google.devtools.build.lib.util.FileType;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.PathFragment;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.UUID;
import java.util.regex.Pattern;

/**
 * Builder class to construct C++ compile actions.
 */
public class CppCompileActionBuilder {
  public static final UUID GUID = UUID.fromString("cee5db0a-d2ad-4c69-9b81-97c936a29075");

  private final ActionOwner owner;
  private final List<String> features = new ArrayList<>();
  private CcToolchainFeatures.FeatureConfiguration featureConfiguration;
  private CcToolchainFeatures.Variables variables;
  private final Artifact sourceFile;
  private final Label sourceLabel;
  private final NestedSetBuilder<Artifact> mandatoryInputsBuilder;
  private NestedSetBuilder<Artifact> pluginInputsBuilder;
  private Artifact optionalSourceFile;
  private Artifact outputFile;
  private PathFragment tempOutputFile;
  private DotdFile dotdFile;
  private Artifact gcnoFile;
  private final BuildConfiguration configuration;
  private CppCompilationContext context = CppCompilationContext.EMPTY;
  private final List<String> copts = new ArrayList<>();
  private final List<String> pluginOpts = new ArrayList<>();
  private final List<Pattern> nocopts = new ArrayList<>();
  private AnalysisEnvironment analysisEnvironment;
  private ImmutableList<PathFragment> extraSystemIncludePrefixes = ImmutableList.of();
  private String fdoBuildStamp;
  private boolean usePic; 
  private IncludeResolver includeResolver = CppCompileAction.VOID_INCLUDE_RESOLVER;
  private UUID actionClassId = GUID;
  private Class<? extends CppCompileActionContext> actionContext;
  private CppConfiguration cppConfiguration;
  private ImmutableMap<Artifact, IncludeScannable> lipoScannableMap;
  private RuleContext ruleContext = null;
  // New fields need to be added to the copy constructor.

  /**
   * Creates a builder from a rule. This also uses the configuration and
   * artifact factory from the rule.
   */
  public CppCompileActionBuilder(RuleContext ruleContext, Artifact sourceFile, Label sourceLabel) {
    this.owner = ruleContext.getActionOwner();
    this.actionContext = CppCompileActionContext.class;
    this.cppConfiguration = ruleContext.getFragment(CppConfiguration.class);
    this.analysisEnvironment = ruleContext.getAnalysisEnvironment();
    this.sourceFile = sourceFile;
    this.sourceLabel = sourceLabel;
    this.configuration = ruleContext.getConfiguration();
    this.mandatoryInputsBuilder = NestedSetBuilder.stableOrder();
    this.pluginInputsBuilder = NestedSetBuilder.stableOrder();
    this.lipoScannableMap = getLipoScannableMap(ruleContext);
    this.ruleContext = ruleContext;

    features.addAll(ruleContext.getFeatures());
  }

  private static ImmutableMap<Artifact, IncludeScannable> getLipoScannableMap(
      RuleContext ruleContext) {
    if (!ruleContext.getFragment(CppConfiguration.class).isLipoOptimization()) {
      return null;
    }

    LipoContextProvider provider = ruleContext.getPrerequisite(
        ":lipo_context_collector", Mode.DONT_CHECK, LipoContextProvider.class);
    return provider.getIncludeScannables();
  }

  /**
   * Creates a builder for an owner that is not required to be rule.
   * 
   * <p>If errors are found when creating the {@code CppCompileAction}, builders constructed
   * this way will throw a runtime exception.
   */
  @VisibleForTesting
  public CppCompileActionBuilder(
      ActionOwner owner, AnalysisEnvironment analysisEnvironment, Artifact sourceFile,
      Label sourceLabel, BuildConfiguration configuration) {
    this.owner = owner;
    this.actionContext = CppCompileActionContext.class;
    this.cppConfiguration = configuration.getFragment(CppConfiguration.class);
    this.analysisEnvironment = analysisEnvironment;
    this.sourceFile = sourceFile;
    this.sourceLabel = sourceLabel;
    this.configuration = configuration;
    this.mandatoryInputsBuilder = NestedSetBuilder.stableOrder();
    this.pluginInputsBuilder = NestedSetBuilder.stableOrder();
    this.lipoScannableMap = ImmutableMap.of();
  }

  /**
   * Creates a builder that is a copy of another builder.
   */
  public CppCompileActionBuilder(CppCompileActionBuilder other) {
    this.owner = other.owner;
    this.features.addAll(other.features);
    this.featureConfiguration = other.featureConfiguration;
    this.sourceFile = other.sourceFile;
    this.sourceLabel = other.sourceLabel;
    this.mandatoryInputsBuilder = NestedSetBuilder.<Artifact>stableOrder()
        .addTransitive(other.mandatoryInputsBuilder.build());
    this.pluginInputsBuilder = NestedSetBuilder.<Artifact>stableOrder()
        .addTransitive(other.pluginInputsBuilder.build());
    this.optionalSourceFile = other.optionalSourceFile;
    this.outputFile = other.outputFile;
    this.tempOutputFile = other.tempOutputFile;
    this.dotdFile = other.dotdFile;
    this.gcnoFile = other.gcnoFile;
    this.configuration = other.configuration;
    this.context = other.context;
    this.copts.addAll(other.copts);
    this.pluginOpts.addAll(other.pluginOpts);
    this.nocopts.addAll(other.nocopts);
    this.analysisEnvironment = other.analysisEnvironment;
    this.extraSystemIncludePrefixes = ImmutableList.copyOf(other.extraSystemIncludePrefixes);
    this.includeResolver = other.includeResolver;
    this.actionClassId = other.actionClassId;
    this.actionContext = other.actionContext;
    this.cppConfiguration = other.cppConfiguration;
    this.fdoBuildStamp = other.fdoBuildStamp;
    this.usePic = other.usePic;
    this.lipoScannableMap = other.lipoScannableMap;
    this.ruleContext = other.ruleContext;
  }

  public PathFragment getTempOutputFile() {
    return tempOutputFile;
  }

  public Artifact getSourceFile() {
    return sourceFile;
  }

  public CppCompilationContext getContext() {
    return context;
  }

  public NestedSet<Artifact> getMandatoryInputs() {
    return mandatoryInputsBuilder.build();
  }

  /**
   * Returns the .dwo output file that matches the specified .o output file. If Fission mode
   * isn't enabled for this build, this is null (we don't produce .dwo files in that case).
   */
  private static Artifact getDwoFile(RuleContext ruleContext, Artifact outputFile,
      CppConfiguration cppConfiguration) {

    // Only create .dwo's for .o compilations (i.e. not .ii or .S).
    boolean isObjectOutput = CppFileTypes.OBJECT_FILE.matches(outputFile.getExecPath())
        || CppFileTypes.PIC_OBJECT_FILE.matches(outputFile.getExecPath());

    // Note configurations can be null for tests.
    if (cppConfiguration != null && cppConfiguration.useFission() && isObjectOutput) {
      return ruleContext.getRelatedArtifact(outputFile.getRootRelativePath(), ".dwo");
    } else {
      return null;
    }
  }

  private static Predicate<String> getNocoptPredicate(Collection<Pattern> patterns) {
    final ImmutableList<Pattern> finalPatterns = ImmutableList.copyOf(patterns);
    if (finalPatterns.isEmpty()) {
      return Predicates.alwaysTrue();
    } else {
      return new Predicate<String>() {
        @Override
        public boolean apply(String option) {
          for (Pattern pattern : finalPatterns) {
            if (pattern.matcher(option).matches()) {
              return false;
            }
          }

          return true;
        }
      };
    }
  }

  private Iterable<IncludeScannable> getLipoScannables(NestedSet<Artifact> realMandatoryInputs) {
    return lipoScannableMap == null ? ImmutableList.<IncludeScannable>of() : Iterables.filter(
        Iterables.transform(
            Iterables.filter(
                FileType.filter(
                    realMandatoryInputs,
                    CppFileTypes.C_SOURCE, CppFileTypes.CPP_SOURCE,
                    CppFileTypes.ASSEMBLER_WITH_C_PREPROCESSOR),
                Predicates.not(Predicates.equalTo(getSourceFile()))),
            Functions.forMap(lipoScannableMap, null)),
        Predicates.notNull());
  }

  /**
   * Builds the Action as configured and returns the to be generated Artifact.
   *
   * <p>This method may be called multiple times to create multiple compile
   * actions (usually after calling some setters to modify the generated
   * action).
   */
  public CppCompileAction build() {
    // Configuration can be null in tests.
    NestedSetBuilder<Artifact> realMandatoryInputsBuilder = NestedSetBuilder.compileOrder();
    realMandatoryInputsBuilder.addTransitive(mandatoryInputsBuilder.build());
    if (tempOutputFile == null && configuration != null
        && !configuration.getFragment(CppConfiguration.class).shouldScanIncludes()) {
      realMandatoryInputsBuilder.addTransitive(context.getDeclaredIncludeSrcs());
    }
    realMandatoryInputsBuilder.addTransitive(context.getAdditionalInputs());
    realMandatoryInputsBuilder.addTransitive(pluginInputsBuilder.build());
    realMandatoryInputsBuilder.add(sourceFile);
    boolean fake = tempOutputFile != null;

    // Copying the collections is needed to make the builder reusable.
    if (fake) {
      return new FakeCppCompileAction(owner, ImmutableList.copyOf(features), featureConfiguration,
          variables, sourceFile, sourceLabel, realMandatoryInputsBuilder.build(), outputFile,
          tempOutputFile, dotdFile, configuration, cppConfiguration, context, actionContext,
          ImmutableList.copyOf(copts), ImmutableList.copyOf(pluginOpts),
          getNocoptPredicate(nocopts), extraSystemIncludePrefixes, fdoBuildStamp, ruleContext,
          usePic);
    } else {
      NestedSet<Artifact> realMandatoryInputs = realMandatoryInputsBuilder.build();

      return new CppCompileAction(owner, ImmutableList.copyOf(features), featureConfiguration,
          variables, sourceFile, sourceLabel, realMandatoryInputs, outputFile, dotdFile,
          gcnoFile, getDwoFile(ruleContext, outputFile, cppConfiguration),
          optionalSourceFile, configuration, cppConfiguration, context,
          actionContext, ImmutableList.copyOf(copts),
          ImmutableList.copyOf(pluginOpts),
          getNocoptPredicate(nocopts),
          extraSystemIncludePrefixes, fdoBuildStamp,
          includeResolver, getLipoScannables(realMandatoryInputs), actionClassId,
          usePic, ruleContext);
    }
  }
  
  /**
   * Sets the feature configuration to be used for the action. 
   */
  public CppCompileActionBuilder setFeatureConfiguration(
      FeatureConfiguration featureConfiguration) {
    this.featureConfiguration = featureConfiguration;
    return this;
  }
  
  /**
   * Sets the feature build variables to be used for the action. 
   */
  public CppCompileActionBuilder setVariables(CcToolchainFeatures.Variables variables) {
    this.variables = variables;
    return this;
  }

  public CppCompileActionBuilder setIncludeResolver(IncludeResolver includeResolver) {
    this.includeResolver = includeResolver;
    return this;
  }

  public CppCompileActionBuilder setCppConfiguration(CppConfiguration cppConfiguration) {
    this.cppConfiguration = cppConfiguration;
    return this;
  }

  public CppCompileActionBuilder setActionContext(
      Class<? extends CppCompileActionContext> actionContext) {
    this.actionContext = actionContext;
    return this;
  }

  public CppCompileActionBuilder setActionClassId(UUID uuid) {
    this.actionClassId = uuid;
    return this;
  }

  public CppCompileActionBuilder setExtraSystemIncludePrefixes(
      Collection<PathFragment> extraSystemIncludePrefixes) {
    this.extraSystemIncludePrefixes = ImmutableList.copyOf(extraSystemIncludePrefixes);
    return this;
  }

  public CppCompileActionBuilder addPluginInput(Artifact artifact) {
    pluginInputsBuilder.add(artifact);
    return this;
  }

  public CppCompileActionBuilder clearPluginInputs() {
    pluginInputsBuilder = NestedSetBuilder.stableOrder();
    return this;
  }

  /**
   * Set an optional source file (usually with metadata of the main source file). The optional
   * source file can only be set once, whether via this method or through the constructor
   * {@link #CppCompileActionBuilder(CppCompileActionBuilder)}.
   */
  public CppCompileActionBuilder addOptionalSourceFile(Artifact artifact) {
    Preconditions.checkState(optionalSourceFile == null, "%s %s", optionalSourceFile, artifact);
    optionalSourceFile = artifact;
    return this;
  }

  public CppCompileActionBuilder addMandatoryInputs(Iterable<Artifact> artifacts) {
    mandatoryInputsBuilder.addAll(artifacts);
    return this;
  }

  public CppCompileActionBuilder addTransitiveMandatoryInputs(NestedSet<Artifact> artifacts) {
    mandatoryInputsBuilder.addTransitive(artifacts);
    return this;
  }

  public CppCompileActionBuilder setOutputFile(Artifact outputFile) {
    this.outputFile = outputFile;
    return this;
  }

  /**
   * The temp output file is not an artifact, since it does not appear in the outputs of the
   * action.
   *
   * <p>This is theoretically a problem if that file already existed before, since then Blaze
   * does not delete it before executing the rule, but 1. that only applies for local
   * execution which does not happen very often and 2. it is only a problem if the compiler is
   * affected by the presence of this file, which it should not be.
   */
  public CppCompileActionBuilder setTempOutputFile(PathFragment tempOutputFile) {
    this.tempOutputFile = tempOutputFile;
    return this;
  }

  @VisibleForTesting
  public CppCompileActionBuilder setDotdFileForTesting(Artifact dotdFile) {
    this.dotdFile = new DotdFile(dotdFile);
    return this;
  }

  public CppCompileActionBuilder setDotdFile(PathFragment outputName, String extension) {
    if (CppFileTypes.mustProduceDotdFile(outputName.toString())) {
      if (configuration.getFragment(CppConfiguration.class).getInmemoryDotdFiles()) {
        // Just set the path, no artifact is constructed
        PathFragment file = FileSystemUtils.replaceExtension(outputName, extension);
        Root root = configuration.getBinDirectory();
        dotdFile = new DotdFile(root.getExecPath().getRelative(file));
      } else {
        dotdFile = new DotdFile(ruleContext.getRelatedArtifact(outputName, extension));
      }
    } else {
      dotdFile = null;
    }
    return this;
  }

  public CppCompileActionBuilder setGcnoFile(Artifact gcnoFile) {
    this.gcnoFile = gcnoFile;
    return this;
  }

  public CppCompileActionBuilder addCopt(String copt) {
    copts.add(copt);
    return this;
  }

  public CppCompileActionBuilder addPluginOpt(String opt) {
    pluginOpts.add(opt);
    return this;
  }

  public CppCompileActionBuilder clearPluginOpts() {
    pluginOpts.clear();
    return this;
  }

  public CppCompileActionBuilder addCopts(Iterable<? extends String> copts) {
    Iterables.addAll(this.copts, copts);
    return this;
  }

  public CppCompileActionBuilder addCopts(int position, Iterable<? extends String> copts) {
    this.copts.addAll(position, ImmutableList.copyOf(copts));
    return this;
  }

  public CppCompileActionBuilder addNocopts(Pattern nocopts) {
    this.nocopts.add(nocopts);
    return this;
  }

  public CppCompileActionBuilder setContext(CppCompilationContext context) {
    this.context = context;
    return this;
  }

  public CppCompileActionBuilder setFdoBuildStamp(String fdoBuildStamp) {
    this.fdoBuildStamp = fdoBuildStamp;
    return this;
  }

  /**
   * Sets whether the CompileAction should use pic mode.
   */
  public CppCompileActionBuilder setPicMode(boolean usePic) {
    this.usePic = usePic;
    return this;
  }
}