تشخیص صحت کد شبا در گولنگ | validate IR sheba code

check_sheba.go

func CheckSheba(text string) bool {
	matched, err := regexp.MatchString("^IR[0-9]{24}$", text)
	if err != nil || matched != true {
		return false
	}
	firstForChars := ""
	sheba := ""
	for index := range text {
		if index < 4 {
			if string(text[index]) == "I" {
				firstForChars = firstForChars + "18"
			} else if string(text[index]) == "R" {
				firstForChars = firstForChars + "27"
			} else {
				firstForChars = firstForChars + string(text[index])
			}
		} else {
			sheba = sheba + string(text[index])
		}
	}
	sheba = sheba + firstForChars
	bigNum97 := big.NewInt(97)
	n := new(big.Int)
	shebaNumber, ok := n.SetString(sheba, 10)
	if !ok {
		return false
	}
	bigNum1 := new(big.Int)
	bigNum1.SetInt64(1)
	return 0 == bigNum1.Cmp(shebaNumber.Mod(shebaNumber, bigNum97))
}