prepareForTelegram function

Implementation

TelegramPreparedMessage prepareForTelegram(String text, {int maxChars = 4000}) {
  // Convert to Telegram MarkdownV2
  final converted = toTelegramMarkdownV2(text);

  // Check if truncation needed
  if (converted.length <= maxChars) {
    return TelegramPreparedMessage(text: converted);
  }

  // Find last newline before limit for clean truncation
  final lastNewline = converted.lastIndexOf('\n', maxChars);

  // If no good newline found, it might be a single long line
  if (lastNewline < maxChars ~/ 2) {
    if (!converted.contains('\n') || converted.indexOf('\n') > maxChars) {
      return TelegramPreparedMessage(
        text: '\\(Line too long \\- sent as attachment\\)',
        wasTruncated: true,
        isSingleLongLine: true,
        remainingChars: converted.length,
      );
    }
  }

  // Truncate at last newline
  final cutPoint = lastNewline > 0 ? lastNewline : maxChars;
  final truncated = converted.substring(0, cutPoint);
  final remaining = converted.length - cutPoint;

  return TelegramPreparedMessage(
    text: '$truncated\n\n\\.\\.\\. \\[$remaining more chars\\]',
    wasTruncated: true,
    remainingChars: remaining,
  );
}