//===- DependencyScanningTool.cpp - clang-scan-deps service ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
#include "clang/Frontend/Utils.h"
#include <optional>

using namespace clang;
using namespace tooling;
using namespace dependencies;

DependencyScanningTool::DependencyScanningTool(
    DependencyScanningService &Service,
    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS)
    : Worker(Service, std::move(FS)) {}

namespace {
/// Prints out all of the gathered dependencies into a string.
class MakeDependencyPrinterConsumer : public DependencyConsumer {
public:
  void handleBuildCommand(Command) override {}

  void
  handleDependencyOutputOpts(const DependencyOutputOptions &Opts) override {
    this->Opts = std::make_unique<DependencyOutputOptions>(Opts);
  }

  void handleFileDependency(StringRef File) override {
    Dependencies.push_back(std::string(File));
  }

  // These are ignored for the make format as it can't support the full
  // set of deps, and handleFileDependency handles enough for implicitly
  // built modules to work.
  void handlePrebuiltModuleDependency(PrebuiltModuleDep PMD) override {}
  void handleModuleDependency(ModuleDeps MD) override {}
  void handleDirectModuleDependency(ModuleID ID) override {}
  void handleContextHash(std::string Hash) override {}

  void printDependencies(std::string &S) {
    assert(Opts && "Handled dependency output options.");

    class DependencyPrinter : public DependencyFileGenerator {
    public:
      DependencyPrinter(DependencyOutputOptions &Opts,
                        ArrayRef<std::string> Dependencies)
          : DependencyFileGenerator(Opts) {
        for (const auto &Dep : Dependencies)
          addDependency(Dep);
      }

      void printDependencies(std::string &S) {
        llvm::raw_string_ostream OS(S);
        outputDependencyFile(OS);
      }
    };

    DependencyPrinter Generator(*Opts, Dependencies);
    Generator.printDependencies(S);
  }

protected:
  std::unique_ptr<DependencyOutputOptions> Opts;
  std::vector<std::string> Dependencies;
};
} // anonymous namespace

llvm::Expected<std::string> DependencyScanningTool::getDependencyFile(
    const std::vector<std::string> &CommandLine, StringRef CWD) {
  MakeDependencyPrinterConsumer Consumer;
  CallbackActionController Controller(nullptr);
  auto Result =
      Worker.computeDependencies(CWD, CommandLine, Consumer, Controller);
  if (Result)
    return std::move(Result);
  std::string Output;
  Consumer.printDependencies(Output);
  return Output;
}

llvm::Expected<P1689Rule> DependencyScanningTool::getP1689ModuleDependencyFile(
    const CompileCommand &Command, StringRef CWD, std::string &MakeformatOutput,
    std::string &MakeformatOutputPath) {
  class P1689ModuleDependencyPrinterConsumer
      : public MakeDependencyPrinterConsumer {
  public:
    P1689ModuleDependencyPrinterConsumer(P1689Rule &Rule,
                                         const CompileCommand &Command)
        : Filename(Command.Filename), Rule(Rule) {
      Rule.PrimaryOutput = Command.Output;
    }

    void handleProvidedAndRequiredStdCXXModules(
        std::optional<P1689ModuleInfo> Provided,
        std::vector<P1689ModuleInfo> Requires) override {
      Rule.Provides = Provided;
      if (Rule.Provides)
        Rule.Provides->SourcePath = Filename.str();
      Rule.Requires = Requires;
    }

    StringRef getMakeFormatDependencyOutputPath() {
      if (Opts->OutputFormat != DependencyOutputFormat::Make)
        return {};
      return Opts->OutputFile;
    }

  private:
    StringRef Filename;
    P1689Rule &Rule;
  };

  class P1689ActionController : public DependencyActionController {
  public:
    // The lookupModuleOutput is for clang modules. P1689 format don't need it.
    std::string lookupModuleOutput(const ModuleID &,
                                   ModuleOutputKind Kind) override {
      return "";
    }
  };

  P1689Rule Rule;
  P1689ModuleDependencyPrinterConsumer Consumer(Rule, Command);
  P1689ActionController Controller;
  auto Result = Worker.computeDependencies(CWD, Command.CommandLine, Consumer,
                                           Controller);
  if (Result)
    return std::move(Result);

  MakeformatOutputPath = Consumer.getMakeFormatDependencyOutputPath();
  if (!MakeformatOutputPath.empty())
    Consumer.printDependencies(MakeformatOutput);
  return Rule;
}

llvm::Expected<TranslationUnitDeps>
DependencyScanningTool::getTranslationUnitDependencies(
    const std::vector<std::string> &CommandLine, StringRef CWD,
    const llvm::DenseSet<ModuleID> &AlreadySeen,
    LookupModuleOutputCallback LookupModuleOutput) {
  FullDependencyConsumer Consumer(AlreadySeen);
  CallbackActionController Controller(LookupModuleOutput);
  llvm::Error Result =
      Worker.computeDependencies(CWD, CommandLine, Consumer, Controller);
  if (Result)
    return std::move(Result);
  return Consumer.takeTranslationUnitDeps();
}

llvm::Expected<ModuleDepsGraph> DependencyScanningTool::getModuleDependencies(
    StringRef ModuleName, const std::vector<std::string> &CommandLine,
    StringRef CWD, const llvm::DenseSet<ModuleID> &AlreadySeen,
    LookupModuleOutputCallback LookupModuleOutput) {
  FullDependencyConsumer Consumer(AlreadySeen);
  CallbackActionController Controller(LookupModuleOutput);
  llvm::Error Result = Worker.computeDependencies(CWD, CommandLine, Consumer,
                                                  Controller, ModuleName);
  if (Result)
    return std::move(Result);
  return Consumer.takeModuleGraphDeps();
}

TranslationUnitDeps FullDependencyConsumer::takeTranslationUnitDeps() {
  TranslationUnitDeps TU;

  TU.ID.ContextHash = std::move(ContextHash);
  TU.FileDeps = std::move(Dependencies);
  TU.PrebuiltModuleDeps = std::move(PrebuiltModuleDeps);
  TU.Commands = std::move(Commands);

  for (auto &&M : ClangModuleDeps) {
    auto &MD = M.second;
    // TODO: Avoid handleModuleDependency even being called for modules
    //   we've already seen.
    if (AlreadySeen.count(M.first))
      continue;
    TU.ModuleGraph.push_back(std::move(MD));
  }
  TU.ClangModuleDeps = std::move(DirectModuleDeps);

  return TU;
}

ModuleDepsGraph FullDependencyConsumer::takeModuleGraphDeps() {
  ModuleDepsGraph ModuleGraph;

  for (auto &&M : ClangModuleDeps) {
    auto &MD = M.second;
    // TODO: Avoid handleModuleDependency even being called for modules
    //   we've already seen.
    if (AlreadySeen.count(M.first))
      continue;
    ModuleGraph.push_back(std::move(MD));
  }

  return ModuleGraph;
}

CallbackActionController::~CallbackActionController() {}