some fixes

utils.go

@@ -39,9 +39,9 @@ func Map[T, V any](ts []T, fn func(T) V) []V {
 }
 
 func EscapeMarkdown(s string) string {
-	s = strings.ReplaceAll(s, "_", "\\_")
-	s = strings.ReplaceAll(s, "*", "\\*")
-	s = strings.ReplaceAll(s, "[", "\\[")
+	s = strings.ReplaceAll(s, "_", `\_`)
+	s = strings.ReplaceAll(s, "*", `\*`)
+	s = strings.ReplaceAll(s, "[", `\[`)
 	return strings.ReplaceAll(s, "`", "\\`")
 }
 
@@ -52,3 +52,57 @@ func EscapeMarkdownV2(s string) string {
 	}
 	return s
 }
+
+func GetUnclosedTag(markdown string) string {
+	// order is important!
+	var tags = []string{
+		"```",
+		"`",
+		"*",
+		"_",
+	}
+	var currentTag = ""
+
+	markdownRunes := []rune(markdown)
+
+	var i = 0
+outer:
+	for i < len(markdownRunes) {
+		// skip escaped characters (only outside tags)
+		if markdownRunes[i] == '\\' && currentTag == "" {
+			i += 2
+			continue
+		}
+		if currentTag != "" {
+			if strings.HasPrefix(string(markdownRunes[i:]), currentTag) {
+				// turn a tag off
+				i += len(currentTag)
+				currentTag = ""
+				continue
+			}
+		} else {
+			for _, tag := range tags {
+				if strings.HasPrefix(string(markdownRunes[i:]), tag) {
+					// turn a tag on
+					currentTag = tag
+					i += len(currentTag)
+					continue outer
+				}
+			}
+		}
+		i++
+	}
+
+	return currentTag
+}
+func IsValid(markdown string) bool {
+	return GetUnclosedTag(markdown) == ""
+}
+
+func FixMarkdown(markdown string) string {
+	tag := GetUnclosedTag(markdown)
+	if tag == "" {
+		return markdown
+	}
+	return markdown + tag
+}