add a way to create custom categories and manage application categories

lib/Service/LangRepository.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace OCA\SideMenu\Service;
+
+use OCP\IDBConnection;
+
+/**
+ * class LangRepository.
+ *
+ * @author Simon Vieille <simon@deblan.fr>
+ */
+class LangRepository
+{
+    /**
+     * @var IDBConnection
+     */
+    protected $db;
+
+    public function __construct(IDBConnection $db)
+    {
+        $this->db = $db;
+    }
+
+    public function getUsedLangs(): array
+    {
+        $qb = $this->db->getQueryBuilder();
+
+        $qb->select($qb->createFunction('DISTINCT configvalue'))
+            ->where('configkey="lang" and appid="core" and configvalue<>"en"')
+            ->from('preferences')
+        ;
+
+        $stmt = $qb->execute();
+
+        $langs = ['en'];
+
+        foreach ($stmt->fetchAll() as $result) {
+            $langs[] = $result['configvalue'];
+        }
+
+        return $langs;
+    }
+}