using DevExpress.XtraRichEdit;
using DevExpress.XtraRichEdit.API.Native;

Stream AddNewComment(Stream inputStream, string commentText, string author, DocumentFormat outputFormat) {
    using var wordProcessor = new RichEditDocumentServer();

    wordProcessor.LoadDocument(inputStream);
    var document = wordProcessor.Document;

    Paragraph paragraph = document.Paragraphs[0];
    Comment comment = document.Comments.Create(paragraph.Range, author);
    SubDocument commentDoc = comment.BeginUpdate();
    commentDoc.InsertText(commentDoc.Range.Start, commentText);
    comment.EndUpdate(commentDoc);

    var outputStream = new MemoryStream();
    wordProcessor.SaveDocument(outputStream, outputFormat);
    outputStream.Position = 0;
    return outputStream;
}

Stream ReplyToComment(Stream inputStream, string replyText, string author, DocumentFormat outputFormat) {
    using var wordProcessor = new RichEditDocumentServer();

    wordProcessor.LoadDocument(inputStream);
    var document = wordProcessor.Document;

    // Reply to the first comment
    if(document.Comments.Count > 0) {
        Comment parentComment = document.Comments[0];
        Comment replyComment = document.Comments.Create(author, parentComment);
        SubDocument replyDoc = replyComment.BeginUpdate();
        replyDoc.InsertText(replyDoc.Range.Start, replyText);
        replyComment.EndUpdate(replyDoc);
    }

    var outputStream = new MemoryStream();
    wordProcessor.SaveDocument(outputStream, outputFormat);
    outputStream.Position = 0;
    return outputStream;
}

Stream RemoveComments(Stream inputStream, bool removeAll, string authorFilter, DocumentFormat outputFormat) {
    using var wordProcessor = new RichEditDocumentServer();

    wordProcessor.LoadDocument(inputStream);
    var document = wordProcessor.Document;

    if(removeAll) {
        for(int i = document.Comments.Count - 1; i >= 0; i--)
            document.Comments.Remove(document.Comments[i]);
    } else if(!string.IsNullOrWhiteSpace(authorFilter)) {
        for(int i = document.Comments.Count - 1; i >= 0; i--) {
            if(string.Equals(document.Comments[i].Author, authorFilter, StringComparison.OrdinalIgnoreCase)) {
                document.Comments.Remove(document.Comments[i]);
            }
        }
    }

    var outputStream = new MemoryStream();
    wordProcessor.SaveDocument(outputStream, outputFormat);
    outputStream.Position = 0;
    return outputStream;
}