Split long messages when send to telegram

internal/adapter/telegram/split.go

@@ -0,0 +1,62 @@
+package telegram
+
+// splitMessageByWords splits a message into parts of maxLen UTF-8 characters
+// splitting by words to avoid cutting words in the middle
+func (s *TelegramMessageSender) splitMessageByWords(text string, maxLen int) []string {
+	var parts []string
+
+	// If text is already short enough, return as is
+	if len([]rune(text)) <= maxLen {
+		return []string{text}
+	}
+
+	runes := []rune(text)
+
+	for len(runes) > 0 {
+		// Determine the end position for this part
+		end := len(runes)
+		if end > maxLen {
+			end = maxLen
+		}
+
+		// Try to find a good split point (word boundary)
+		splitPoint := end
+		for i := end - 1; i > end-20 && i > 0; i-- { // Look back up to 20 characters
+			// Check if this is a good split point (after a space)
+			if runes[i] == ' ' {
+				splitPoint = i + 1 // Include the space in the previous part
+				break
+			}
+		}
+
+		// If we couldn't find a good split point, just split at maxLen
+		if splitPoint == end && end == maxLen {
+			// Check if we're in the middle of a word
+			if end < len(runes) && runes[end] != ' ' && runes[end-1] != ' ' {
+				// Try to find a split point going forward
+				for i := end; i < len(runes) && i < end+20; i++ {
+					if runes[i] == ' ' {
+						splitPoint = i
+						break
+					}
+				}
+			}
+		}
+
+		// If still no good split point, use the original end
+		if splitPoint > len(runes) {
+			splitPoint = len(runes)
+		}
+
+		// Add this part
+		parts = append(parts, string(runes[:splitPoint]))
+
+		// Move to the next part
+		if splitPoint >= len(runes) {
+			break
+		}
+		runes = runes[splitPoint:]
+	}
+
+	return parts
+}