private static void generateComment(@NotNull PsiElement anchor,
                                      @NotNull Editor editor,
                                      @NotNull CodeDocumentationProvider documentationProvider,
                                      @NotNull CodeDocumentationAwareCommenter commenter,
                                      @NotNull Project project)
  {
    Document document = editor.getDocument();
    int commentStartOffset = anchor.getTextRange().getStartOffset();
    int lineStartOffset = document.getLineStartOffset(document.getLineNumber(commentStartOffset));
    if (lineStartOffset > 0 && lineStartOffset < commentStartOffset) {
      // Example:
      //    void test1() {
      //    }
      //    void test2() {
      //       <offset>
      //    }
      // We want to insert the comment at the start of the line where 'test2()' is declared.
      int nonWhiteSpaceOffset = CharArrayUtil.shiftBackward(document.getCharsSequence(), lineStartOffset, commentStartOffset - 1, " \t") + 1;
      commentStartOffset = Math.max(nonWhiteSpaceOffset, lineStartOffset);
    }

    int commentBodyRelativeOffset = 0;
    int caretOffsetToSet = -1;
    StringBuilder buffer = new StringBuilder();
    String commentPrefix = commenter.getDocumentationCommentPrefix();
    if (commentPrefix != null) {
      buffer.append(commentPrefix).append("\n");
      commentBodyRelativeOffset += commentPrefix.length() + 1;
    }

    String linePrefix = commenter.getDocumentationCommentLinePrefix();
    if (linePrefix != null) {
      buffer.append(linePrefix);
      commentBodyRelativeOffset += linePrefix.length();
      caretOffsetToSet = commentStartOffset + commentBodyRelativeOffset;
    }
    buffer.append("\n");
    commentBodyRelativeOffset++;

    String commentSuffix = commenter.getDocumentationCommentSuffix();
    if (commentSuffix != null) {
      buffer.append(commentSuffix).append("\n");
    }

    if (buffer.length() <= 0) {
      return;
    }

    document.insertString(commentStartOffset, buffer);
    PsiDocumentManager docManager = PsiDocumentManager.getInstance(project);
    docManager.commitDocument(document);

    Pair<PsiElement, PsiComment> pair = documentationProvider.parseContext(anchor);
    if (pair == null || pair.second == null) {
      return;
    }

    String stub = documentationProvider.generateDocumentationContentStub(pair.second);
    CaretModel caretModel = editor.getCaretModel();
    if (stub != null) {
      int insertionOffset = commentStartOffset + commentBodyRelativeOffset;
      document.insertString(insertionOffset, stub);
      docManager.commitDocument(document);
      pair = documentationProvider.parseContext(anchor);
    }

    if (caretOffsetToSet >= 0) {
      caretModel.moveToOffset(caretOffsetToSet);
      editor.getSelectionModel().removeSelection();
    }

    if (pair == null || pair.second == null) {
      return;
    }

    int start = Math.min(calcStartReformatOffset(pair.first), calcStartReformatOffset(pair.second));
    int end = pair.second.getTextRange().getEndOffset();

    reformatCommentKeepingEmptyTags(anchor.getContainingFile(), project, start, end);
    editor.getCaretModel().moveToOffset(document.getLineEndOffset(document.getLineNumber(editor.getCaretModel().getOffset())));

    int caretOffset = caretModel.getOffset();
    if (caretOffset > 0 && caretOffset <= document.getTextLength()) {
      char c = document.getCharsSequence().charAt(caretOffset - 1);
      if (!StringUtil.isWhiteSpace(c)) {
        document.insertString(caretOffset, " ");
        caretModel.moveToOffset(caretOffset + 1);
      }
    }
  }
private static void generateComment(@NotNull PsiElement anchor,
                                      @NotNull Editor editor,
                                      @NotNull CodeDocumentationProvider documentationProvider,
                                      @NotNull CodeDocumentationAwareCommenter commenter,
                                      @NotNull Project project)