fix: clean code

cmd/gotp/main.go

@@ -63,7 +63,9 @@ func main() {
 	case "get":
 		err := getCmd.Parse(os.Args[2:])
 		check(err)
-		totp, err := gotp.Get(*getKey)
+		totp, err := gotp.
+			WithTimeIntervalSeed(30).
+			Get(*getKey)
 		check(err)
 		fmt.Printf("%s", totp)
 		err = clipboard.WriteAll(totp)

gotp.go

@@ -8,19 +8,30 @@ import (
 )
 
 // DefaultTimeIntervalSeedTimeIntervalSeed is the default time interval seed used to compute the HOTP.
-const DefaultTimeIntervalSeed int64 = 30
+const DefaultTimeIntervalSeed uint = 30
 
 type GOTP struct {
 	secRing *secure.Secure
+	timeIntervalSeed uint
 }
 
+// New instanciates a GoTP object with a secured backend
 func New(secring *secure.Secure) *GOTP {
-	// create the key ring
 	return &GOTP{
+		timeIntervalSeed: DefaultTimeIntervalSeed,
 		secRing: secring,
 	}
 }
 
+// WithTimeIntervalSeed configures a specific timeIntervalSeed
+func (gotp *GOTP) WithTimeIntervalSeed(interval uint) *GOTP {
+	g := &GOTP{}
+	*g = *gotp
+
+	g.timeIntervalSeed = interval
+	return g
+}
+
 // List retrieves all existing keys in the secured key ring
 func (gotp *GOTP) List() ([]string, error) {
 	return gotp.secRing.List()
@@ -43,7 +54,7 @@ func (gotp *GOTP) Get(key string) (string, error) {
 		return "", err
 	}
 	return totp.GenerateCodeCustom(string(secret), time.Now(), totp.ValidateOpts{
-		Period:    30,
+		Period:    gotp.timeIntervalSeed,
 		Skew:      1,
 		Digits:    otp.DigitsSix,
 		Algorithm: otp.AlgorithmSHA1,