@Override
    protected void addCompletions(
        @NotNull CompletionParameters completionParameters,
        final ProcessingContext processingContext,
        @NotNull final CompletionResultSet completionResultSet) {

      PsiFile originalFile = completionParameters.getOriginalFile();
      final PsiDirectory containingDirectory = originalFile.getContainingDirectory();
      if (containingDirectory == null) {
        return;
      }

      final VirtualFile containingDirectoryFiles = containingDirectory.getVirtualFile();
      VfsUtil.visitChildrenRecursively(
          containingDirectoryFiles,
          new VirtualFileVisitor() {
            @Override
            public boolean visitFile(@NotNull VirtualFile file) {

              String relativePath = VfsUtil.getRelativePath(file, containingDirectoryFiles, '/');
              if (relativePath == null) {
                return super.visitFile(file);
              }

              completionResultSet.addElement(
                  LookupElementBuilder.create(relativePath).withIcon(file.getFileType().getIcon()));

              return super.visitFile(file);
            }
          });
    }