internal static (string, string) SplitResultMessage(string input, int maxLength)
{
if (string.IsNullOrWhiteSpace(input))
{
return(input, input);
}
const string ellipsis = "\u2026";
const string hyperlinkGroup = "link_text";
string pattern = $"\\[(?<{hyperlinkGroup}>[\\w \\.]+)\\]\\(([\\w\\.:\\/ ]*)\\)";
MatchCollection matches = Regex.Matches(input, pattern, RegexOptions.Multiline);
var sb = new StringBuilder(input);
// Replace the hyperlinks with only their text
for (int i = matches.Count - 1; i >= 0; i--)
{
Match match = matches[i];
// match.Groups.TryGetValue only available in .net 5/.net core 3.0 or above
Group group = match.Groups[hyperlinkGroup];
if (group != null && group.Success)
{
string text = group.Value;
sb = sb.Remove(match.Index, match.Length);
sb = sb.Insert(match.Index, text);
}
}
string fullText = AppendEndPunctuation(input);
string firstSentence = ExtensionMethods.GetFirstSentence(sb.ToString());
// ExtensionMethods.GetFirstSentence has an issue it appends '.' even the string ends with other punctuations '!' or '?'
firstSentence = AppendEndPunctuation(firstSentence.TrimEnd('.'));
sb = new StringBuilder(firstSentence);
bool addEllipsis = maxLength > 0 && sb.Length > maxLength;
if (addEllipsis)
{
// Truncate the string
sb.Length = maxLength;
}
// Restore the remaining intact links
foreach (Match match in matches)
{
Group group = match.Groups[hyperlinkGroup];
if (group != null && group.Success)
{
if (maxLength > 0 && match.Index + group.Length <= sb.Length)
{
sb = sb.Remove(match.Index, group.Length);
sb = sb.Insert(match.Index, match.Value);
maxLength += match.Value.Length - group.Length;
}
else
{
break;
}
}
}
if (addEllipsis)
{
sb.Append(ellipsis);
}
return(sb.ToString(), fullText);
}