Replace comma with minus in filename

classes/local/helpers/download.php

@@ -41,12 +41,16 @@ class download {
         }
 
         $timestamp = download::get_file_timestamp();
+        $filename = $course_code;
 
-        if ($course_code != null) {
-            $filename = FILENAME_PREFIX . $course_code . '_' . $timestamp;
-        } else {
-            $filename = FILENAME_PREFIX . $course->shortname . '_' . $timestamp;
+        // use course shortname if no course_code is given
+        if ($course_code == null) {
+            $filename = str_replace(',', '-', $course->shortname);
         }
+
+        // extend filename with prefix and date
+        $filename = FILENAME_PREFIX . $filename . '_' . $timestamp;
+
         return $filename;
     }