//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_DEPENDENCYSCANNING_DEPENDENCYSCANNINGWORKER_H
#define LLVM_CLANG_DEPENDENCYSCANNING_DEPENDENCYSCANNINGWORKER_H

#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/LLVM.h"
#include "clang/DependencyScanning/DependencyScannerImpl.h"
#include "clang/DependencyScanning/DependencyScanningService.h"
#include "clang/DependencyScanning/ModuleDepCollector.h"
#include "clang/Frontend/PCHContainerOperations.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBufferRef.h"
#include "llvm/Support/VirtualFileSystem.h"
#include <optional>
#include <string>

namespace clang {

class DependencyOutputOptions;

namespace dependencies {

class DependencyScanningWorkerFilesystem;
class CompilerInstanceWithContext;

/// A command-line tool invocation that is part of building a TU.
///
/// \see TranslationUnitDeps::Commands.
struct Command {
  std::string Executable;
  std::vector<std::string> Arguments;
};

class DependencyConsumer {
public:
  virtual ~DependencyConsumer() {}

  virtual void handleProvidedAndRequiredStdCXXModules(
      std::optional<P1689ModuleInfo> Provided,
      std::vector<P1689ModuleInfo> Requires) {}

  virtual void handleBuildCommand(Command Cmd) {}

  virtual void
  handleDependencyOutputOpts(const DependencyOutputOptions &Opts) = 0;

  virtual void handleFileDependency(StringRef Filename) = 0;

  virtual void handlePrebuiltModuleDependency(PrebuiltModuleDep PMD) = 0;

  virtual void handleModuleDependency(ModuleDeps MD) = 0;

  virtual void handleDirectModuleDependency(ModuleID MD) = 0;

  virtual void handleVisibleModule(std::string ModuleName) = 0;

  virtual void handleContextHash(std::string Hash) = 0;
};

/// Dependency scanner callbacks that are used during scanning to influence the
/// behaviour of the scan - for example, to customize the scanned invocations.
class DependencyActionController {
public:
  virtual ~DependencyActionController();

  virtual std::string lookupModuleOutput(const ModuleDeps &MD,
                                         ModuleOutputKind Kind) = 0;
};

/// An individual dependency scanning worker that is able to run on its own
/// thread.
///
/// The worker computes the dependencies for the input files by preprocessing
/// sources either using a fast mode where the source files are minimized, or
/// using the regular processing run.
class DependencyScanningWorker {
public:
  /// Construct a dependency scanning worker.
  ///
  /// @param Service The parent service. Must outlive the worker.
  /// @param BaseFS The filesystem for the worker to use.
  DependencyScanningWorker(DependencyScanningService &Service,
                           IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS);

  ~DependencyScanningWorker();

  /// Run the dependency scanning worker for the given frontend command-line,
  /// and report the discovered dependencies to the provided consumer.
  ///
  /// OverlayFS should be based on the Worker's dependency scanning file-system
  /// and can be used to provide any input specified on the command-line as
  /// in-memory file. If no overlay file-system is provided, the Worker's
  /// dependency scanning file-system is used instead.
  ///
  /// \returns false if any errors occurred (with diagnostics reported to
  /// \c DiagConsumer), true otherwise.
  bool computeDependencies(
      StringRef WorkingDirectory, ArrayRef<std::string> CommandLine,
      DependencyConsumer &DepConsumer, DependencyActionController &Controller,
      DiagnosticConsumer &DiagConsumer,
      llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFS =
          nullptr);

  /// Run the dependency scanning tool for all given frontend command-lines,
  /// and report the discovered dependencies to the provided consumer.
  ///
  /// OverlayFS should be based on the Worker's dependency scanning file-system
  /// and can be used to provide any input specified on the command-line as
  /// in-memory file. If no overlay file-system is provided, the Worker's
  /// dependency scanning file-system is used instead.
  ///
  /// \returns false if any errors occurred (with diagnostics reported to
  /// \c DiagConsumer), true otherwise.
  bool computeDependencies(
      StringRef WorkingDirectory, ArrayRef<ArrayRef<std::string>> CommandLines,
      DependencyConsumer &DepConsumer, DependencyActionController &Controller,
      DiagnosticConsumer &DiagConsumer,
      llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFS =
          nullptr);

  /// The three method below implements a new interface for by name
  /// dependency scanning. They together enable the dependency scanning worker
  /// to more effectively perform scanning for a sequence of modules
  /// by name when the CWD and CommandLine do not change across the queries.
  /// The initialization function asks the client for a DiagnosticsConsumer
  /// that it direct the diagnostics to.

  /// @brief Initializing the context and the compiler instance.
  /// @param CWD The current working directory used during the scan.
  /// @param CommandLine The commandline used for the scan.
  /// @return False if the initializaiton fails.
  bool initializeCompilerInstanceWithContext(StringRef CWD,
                                             ArrayRef<std::string> CommandLine,
                                             DiagnosticConsumer &DC);

  /// @brief Initializing the context and the compiler instance.
  /// @param CWD The current working directory used during the scan.
  /// @param CommandLine The commandline used for the scan.
  /// @param DiagEngineWithCmdAndOpts Preconfigured diagnostics engine and
  /// options associated with the cc1 command line.
  /// @param FS The overlay file system to use for this compiler instance.
  /// @return False if the initializaiton fails.
  bool initializeCompilerInstanceWithContext(
      StringRef CWD, ArrayRef<std::string> CommandLine,
      std::unique_ptr<DiagnosticsEngineWithDiagOpts> DiagEngineWithCmdAndOpts,
      IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFS);

  /// @brief Performaces dependency scanning for the module whose name is
  ///        specified.
  /// @param ModuleName  The name of the module whose dependency will be
  ///                    scanned.
  /// @param Consumer The dependency consumer that stores the results.
  /// @param Controller The controller for the dependency scanning action.
  /// @return False if the scanner incurs errors.
  bool
  computeDependenciesByNameWithContext(StringRef ModuleName,
                                       DependencyConsumer &Consumer,
                                       DependencyActionController &Controller);

  /// @brief Finalizes the diagnostics engine and deletes the compiler instance.
  /// @return False if errors occur during finalization.
  bool finalizeCompilerInstanceWithContext();

  llvm::vfs::FileSystem &getVFS() const { return *DepFS; }

private:
  /// The parent dependency scanning service.
  DependencyScanningService &Service;
  std::shared_ptr<PCHContainerOperations> PCHContainerOps;
  /// This is the caching (and optionally dependency-directives-providing) VFS
  /// overlaid on top of the base VFS passed in the constructor.
  IntrusiveRefCntPtr<DependencyScanningWorkerFilesystem> DepFS;

  friend CompilerInstanceWithContext;
  std::unique_ptr<CompilerInstanceWithContext> CIWithContext;
};

std::pair<IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>,
          std::vector<std::string>>
initVFSForTUBufferScanning(IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
                           ArrayRef<std::string> CommandLine,
                           StringRef WorkingDirectory,
                           llvm::MemoryBufferRef TUBuffer);

std::pair<IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem>,
          std::vector<std::string>>
initVFSForByNameScanning(IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
                         ArrayRef<std::string> CommandLine,
                         StringRef WorkingDirectory, StringRef ModuleName);

} // end namespace dependencies
} // end namespace clang

#endif // LLVM_CLANG_DEPENDENCYSCANNING_DEPENDENCYSCANNINGWORKER_H