referrals: add "use expiry" option

adds an option when enabling referrals to use the duration of the source
invited (i.e., months, days, hours) for the referral invite. If enabled,
the user won't be able to make a new referral link after it expires. For
referrals enabled for new users via a profile, the clock starts ticking
as soon as the account is created.

api-invites.go

@@ -45,14 +45,24 @@ func (app *appContext) checkInvites() {
 			app.storage.SetInvitesKey(data.Code, data)
 		}
 
-		if data.IsReferral {
+		if data.IsReferral && (!data.UseReferralExpiry || data.ReferrerJellyfinID == "") {
 			continue
 		}
 		expiry := data.ValidTill
 		if !currentTime.After(expiry) {
 			continue
 		}
+
 		app.debug.Printf("Housekeeping: Deleting old invite %s", data.Code)
+
+		// Disable referrals for the user if UseReferralExpiry is enabled, so no new ones are made.
+		if data.IsReferral && data.UseReferralExpiry && data.ReferrerJellyfinID != "" {
+			user, ok := app.storage.GetEmailsKey(data.ReferrerJellyfinID)
+			if ok {
+				user.ReferralTemplateKey = ""
+				app.storage.SetEmailsKey(data.ReferrerJellyfinID, user)
+			}
+		}
 		notify := data.Notify
 		if emailEnabled && app.config.Section("notifications").Key("enabled").MustBool(false) && len(notify) != 0 {
 			app.debug.Printf("%s: Expiry notification", data.Code)
@@ -136,6 +146,13 @@ func (app *appContext) checkInvite(code string, used bool, username string) bool
 			}
 			wait.Wait()
 		}
+		if inv.IsReferral && inv.ReferrerJellyfinID != "" && inv.UseReferralExpiry {
+			user, ok := app.storage.GetEmailsKey(inv.ReferrerJellyfinID)
+			if ok {
+				user.ReferralTemplateKey = ""
+				app.storage.SetEmailsKey(inv.ReferrerJellyfinID, user)
+			}
+		}
 		match = false
 		app.storage.DeleteInvitesKey(code)
 		app.storage.SetActivityKey(shortuuid.New(), Activity{