Added possibility to show backup codes in user settings.

src/Services/TFA/BackupCodeGenerator.php

@@ -46,7 +46,6 @@ class BackupCodeGenerator
     /**
      * Returns a full backup code set. The code count can be configured in the constructor
      * @return string[] An array containing different backup codes.
-     * @throws \Exception If no entropy source is available
      */
     public function generateCodeSet() : array
     {

src/Services/TFA/BackupCodeManager.php

@@ -0,0 +1,57 @@
+<?php
+
+
+namespace App\Services\TFA;
+
+
+use App\Entity\UserSystem\User;
+
+/**
+ * This services offers methods to manage backup codes for two factor authentication
+ * @package App\Services\TFA
+ */
+class BackupCodeManager
+{
+    protected $backupCodeGenerator;
+
+    public function __construct(BackupCodeGenerator $backupCodeGenerator)
+    {
+        $this->backupCodeGenerator = $backupCodeGenerator;
+    }
+
+    /**
+     * Enable backup codes for the given user, by generating a set of backup codes.
+     * If the backup codes were already enabled before, they a
+     * @param  User  $user
+     */
+    public function enableBackupCodes(User $user)
+    {
+        if(empty($user->getBackupCodes())) {
+           $this->regenerateBackupCodes($user);
+        }
+    }
+
+    /**
+     * Disable (remove) the backup codes when no other 2 factor authentication methods are enabled.
+     * @param  User  $user
+     */
+    public function disableBackupCodesIfUnused(User $user)
+    {
+        if($user->isU2FAuthEnabled() || $user->isGoogleAuthenticatorEnabled()) {
+            return;
+        }
+
+        $user->setBackupCodes([]);
+    }
+
+    /**
+     * Generates a new set of backup codes for the user. If no backup codes were available before, new ones are
+     * generated.
+     * @param  User  $user The user for which the backup codes should be regenerated
+     */
+    public function regenerateBackupCodes(User $user)
+    {
+        $codes = $this->backupCodeGenerator->generateCodeSet();
+        $user->setBackupCodes($codes);
+    }
+}