invites: move code gen to function

code to generate an invite code w/ a non-integer first character was
reused a bunch, so it's now function GenerateInviteCode().

api-users.go

@@ -3,14 +3,12 @@ package main
 import (
 	"fmt"
 	"os"
-	"strconv"
 	"strings"
 	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/golang-jwt/jwt"
 	"github.com/hrfee/mediabrowser"
-	"github.com/lithammer/shortuuid/v3"
 	"github.com/timshannon/badgerhold/v4"
 )
 
@@ -707,13 +705,7 @@ func (app *appContext) EnableReferralForUsers(gc *gin.Context) {
 
 		// 2. Generate referral invite.
 		inv := baseInv
-		inv.Code = shortuuid.New()
-		// make sure code doesn't begin with number
-		_, err := strconv.Atoi(string(inv.Code[0]))
-		for err == nil {
-			inv.Code = shortuuid.New()
-			_, err = strconv.Atoi(string(inv.Code[0]))
-		}
+		inv.Code = GenerateInviteCode()
 		inv.Created = time.Now()
 		inv.ValidTill = inv.Created.Add(REFERRAL_EXPIRY_DAYS * 24 * time.Hour)
 		inv.IsReferral = true