class FileUploadHandler

class FileUploadHandler implements FileUploadHandlerInterface {
  
  /**
   * The default extensions if none are provided.
   */
  const DEFAULT_EXTENSIONS = 'jpg jpeg gif png txt doc xls pdf ppt pps odt ods odp';
  
  /**
   * The file system service.
   *
   * @var \Drupal\Core\File\FileSystemInterface
   */
  protected $fileSystem;
  
  /**
   * The entity type manager.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;
  
  /**
   * The stream wrapper manager.
   *
   * @var \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface
   */
  protected $streamWrapperManager;
  
  /**
   * The event dispatcher.
   *
   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
   */
  protected $eventDispatcher;
  
  /**
   * The current user.
   *
   * @var \Drupal\Core\Session\AccountInterface
   */
  protected $currentUser;
  
  /**
   * The MIME type guesser.
   *
   * @var \Symfony\Component\Mime\MimeTypeGuesserInterface
   */
  protected $mimeTypeGuesser;
  
  /**
   * The request stack.
   *
   * @var \Symfony\Component\HttpFoundation\RequestStack
   */
  protected $requestStack;
  
  /**
   * The file Repository.
   *
   * @var \Drupal\file\FileRepositoryInterface
   */
  protected $fileRepository;
  
  /**
   * The file validator.
   *
   * @var \Drupal\file\Validation\FileValidatorInterface
   */
  protected FileValidatorInterface $fileValidator;
  public function __construct(FileSystemInterface $fileSystem, EntityTypeManagerInterface $entityTypeManager, StreamWrapperManagerInterface $streamWrapperManager, EventDispatcherInterface $eventDispatcher, MimeTypeGuesserInterface $mimeTypeGuesser, AccountInterface $currentUser, RequestStack $requestStack, FileRepositoryInterface $fileRepository, FileValidatorInterface $file_validator, protected LockBackendInterface $lock, protected BasicRecursiveValidatorFactory $validatorFactory) {
    $this->fileSystem = $fileSystem;
    $this->entityTypeManager = $entityTypeManager;
    $this->streamWrapperManager = $streamWrapperManager;
    $this->eventDispatcher = $eventDispatcher;
    $this->mimeTypeGuesser = $mimeTypeGuesser;
    $this->currentUser = $currentUser;
    $this->requestStack = $requestStack;
    $this->fileRepository = $fileRepository;
    $this->fileValidator = $file_validator;
  }
  
  /**
   * {@inheritdoc}
   */
  public function handleFileUpload(UploadedFileInterface $uploadedFile, array $validators = [], string $destination = 'temporary://', $fileExists = FileExists::Replace) : FileUploadResult {
    if (!$fileExists instanceof FileExists) {
      // @phpstan-ignore staticMethod.deprecated
      $fileExists = FileExists::fromLegacyInt($fileExists, __METHOD__);
    }
    $result = new FileUploadResult();
    $violations = $uploadedFile->validate($this->validatorFactory
      ->createValidator());
    if (count($violations) > 0) {
      $result->addViolations($violations);
      return $result;
    }
    $originalName = $uploadedFile->getClientOriginalName();
    $extensions = $this->handleExtensionValidation($validators);
    // Assert that the destination contains a valid stream.
    $destinationScheme = $this->streamWrapperManager::getScheme($destination);
    if (!$this->streamWrapperManager
      ->isValidScheme($destinationScheme)) {
      throw new InvalidStreamWrapperException(sprintf('The file could not be uploaded because the destination "%s" is invalid.', $destination));
    }
    // A file URI may already have a trailing slash or look like "public://".
    if (!str_ends_with($destination, '/')) {
      $destination .= '/';
    }
    // Call an event to sanitize the filename and to attempt to address security
    // issues caused by common server setups.
    $event = new FileUploadSanitizeNameEvent($originalName, $extensions);
    $this->eventDispatcher
      ->dispatch($event);
    $filename = $event->getFilename();
    $mimeType = $this->mimeTypeGuesser
      ->guessMimeType($filename);
    $destinationFilename = $this->fileSystem
      ->getDestinationFilename($destination . $filename, $fileExists);
    if ($destinationFilename === FALSE) {
      throw new FileExistsException(sprintf('Destination file "%s" exists', $destinationFilename));
    }
    // Lock based on the prepared file URI.
    $lock_id = $this->generateLockId($destinationFilename);
    try {
      if (!$this->lock
        ->acquire($lock_id)) {
        throw new LockAcquiringException(sprintf('File "%s" is already locked for writing.', $destinationFilename));
      }
      $file = File::create([
        'uid' => $this->currentUser
          ->id(),
        'status' => 0,
        'uri' => $uploadedFile->getRealPath(),
      ]);
      // This will be replaced later with a filename based on the destination.
      $file->setFilename($filename);
      $file->setMimeType($mimeType);
      $file->setSize($uploadedFile->getSize());
      // Add in our check of the file name length.
      $validators['FileNameLength'] = [];
      // Call the validation functions specified by this function's caller.
      $violations = $this->fileValidator
        ->validate($file, $validators);
      if (count($violations) > 0) {
        $result->addViolations($violations);
        return $result;
      }
      $file->setFileUri($destinationFilename);
      if (!$this->moveUploadedFile($uploadedFile, $file->getFileUri())) {
        throw new FileWriteException('File upload error. Could not move uploaded file.');
      }
      // Update the filename with any changes as a result of security or
      // renaming due to an existing file.
      $file->setFilename($this->fileSystem
        ->basename($file->getFileUri()));
      if ($fileExists === FileExists::Replace) {
        $existingFile = $this->fileRepository
          ->loadByUri($file->getFileUri());
        if ($existingFile) {
          $file->fid = $existingFile->id();
          $file->setOriginalId($existingFile->id());
        }
      }
      $result->setOriginalFilename($originalName)
        ->setSanitizedFilename($filename)
        ->setFile($file);
      // If the filename has been modified, let the user know.
      if ($event->isSecurityRename()) {
        $result->setSecurityRename();
      }
      // Set the permissions on the new file.
      $this->fileSystem
        ->chmod($file->getFileUri());
      // We can now validate the file object itself before it's saved.
      $violations = $file->validate();
      if (count($violations) > 0) {
        $result->addViolations($violations);
        return $result;
      }
      // If we made it this far it's safe to record this file in the database.
      $file->save();
      // Allow an anonymous user who creates a non-public file to see it. See
      // \Drupal\file\FileAccessControlHandler::checkAccess().
      if ($this->currentUser
        ->isAnonymous() && $destinationScheme !== 'public') {
        $session = $this->requestStack
          ->getCurrentRequest()
          ->getSession();
        $allowed_temp_files = $session->get('anonymous_allowed_file_ids', []);
        $allowed_temp_files[$file->id()] = $file->id();
        $session->set('anonymous_allowed_file_ids', $allowed_temp_files);
      }
    } finally {
      $this->lock
        ->release($lock_id);
    }
    return $result;
  }
  
  /**
   * Move the uploaded file from the temporary path to the destination.
   *
   * @param \Drupal\file\Upload\UploadedFileInterface $uploadedFile
   *   The uploaded file.
   * @param string $uri
   *   The destination URI.
   *
   * @return bool
   *   Returns FALSE if moving failed.
   *
   * @see https://www.drupal.org/project/drupal/issues/2940383
   */
  protected function moveUploadedFile(UploadedFileInterface $uploadedFile, string $uri) : bool {
    if ($uploadedFile instanceof FormUploadedFile) {
      return $this->fileSystem
        ->moveUploadedFile($uploadedFile->getRealPath(), $uri);
    }
    // We use FileExists::Error) as the file location has already
    // been determined above in FileSystem::getDestinationFilename().
    return $this->fileSystem
      ->move($uploadedFile->getRealPath(), $uri, FileExists::Error);
  }
  
  /**
   * Gets the list of allowed extensions and updates the validators.
   *
   * This will add an extension validator to the list of validators if one is
   * not set.
   *
   * If the extension validator is set, but no extensions are specified, it
   * means all extensions are allowed, so the validator is removed from the list
   * of validators.
   *
   * @param array $validators
   *   The file validators in use.
   *
   * @return string
   *   The space delimited list of allowed file extensions.
   */
  protected function handleExtensionValidation(array &$validators) : string {
    // No validator was provided, so add one using the default list.
    // Build a default non-munged safe list for
    // \Drupal\system\EventSubscriber\SecurityFileUploadEventSubscriber::sanitizeName().
    if (!isset($validators['FileExtension'])) {
      $validators['FileExtension'] = [
        'extensions' => self::DEFAULT_EXTENSIONS,
      ];
      return self::DEFAULT_EXTENSIONS;
    }
    // Check if we want to allow all extensions.
    if (!isset($validators['FileExtension']['extensions'])) {
      // If 'FileExtension' is set and the list is empty then the caller wants
      // to allow any extension. In this case we have to remove the validator
      // or else it will reject all extensions.
      unset($validators['FileExtension']);
      return '';
    }
    return $validators['FileExtension']['extensions'];
  }
  
  /**
   * Generates a lock ID based on the file URI.
   */
  protected static function generateLockId(string $fileUri) : string {
    return 'file:upload:' . Crypt::hashBase64($fileUri);
  }

}