moving things around and stub before creating a cmd register

core/text.go

@@ -0,0 +1,53 @@
+package core
+
+import (
+	"regexp"
+	"strings"
+)
+
+// source on www.socketloop.com
+func removeCharacters(input string, characters string) string {
+	filter := func(r rune) rune {
+		if strings.IndexRune(characters, r) < 0 {
+			return r
+		}
+		return -1
+	}
+	return strings.Map(filter, input)
+}
+
+// https://stackoverflow.com/questions/34839659/how-can-i-easily-get-a-substring-in-go-while-guarding-against-slice-bounds-out
+func maxString(s string, max int) string {
+	if len(s) > max {
+		r := 0
+		for i := range s {
+			r++
+			if r > max {
+				return s[:i]
+			}
+		}
+	}
+	return s
+}
+
+// this only strip custom emoji, not default unicode ones
+func stripEmoji(msg string) string {
+	re := regexp.MustCompile(`:\w+:`)
+	match := re.FindAll([]byte(msg), -1)
+	if len(match) > 0 {
+		s := msg
+		for i := range match {
+			s = strings.Replace(s, string(match[i]), "", -1)
+		}
+		return s
+	} else {
+		return msg
+	}
+}
+
+func prepareTTSMessage(msg string) string {
+	t1 := maxString(msg, 300)
+	t2 := stripEmoji(t1)
+	t3 := removeCharacters(t2, "-\"'`$();:.\\")
+	return strings.Trim(t3, " ")
+}