@Override
  public @NotNull IntentionPreviewInfo generatePreview(@NotNull Project project, @NotNull Editor editor, @NotNull PsiFile file) {
    PsiFile containingFile = ref.getContainingFile();
    if (!(containingFile instanceof GroovyFile)) {
      return IntentionPreviewInfo.EMPTY;
    }
    String fileName = containingFile.getName();
    GrImportStatement[] imports = ((GroovyFile)containingFile).getImportStatements();
    StringBuilder builder = new StringBuilder();
    for (GrImportStatement importStmt : imports) {
      builder.append(importStmt.getText());
      builder.append("\n");
    }
    String before = builder.toString();
    builder.append("import package1.package2.").append(ref.getReferenceName());
    String after = builder.toString();
    return new IntentionPreviewInfo.CustomDiff(GroovyFileType.GROOVY_FILE_TYPE, fileName, before, after);
  }
@Override
  public @NotNull IntentionPreviewInfo generatePreview(@NotNull Project project, @NotNull Editor editor, @NotNull PsiFile file)