public function saveNewLesson()
 {
     if (!isset($_POST['nameEN']) || empty($_POST['nameEN']) || !isset($_POST['nameDE']) || empty($_POST['nameDE']) || !isset($_POST['points']) || empty($_POST['points'])) {
         $this->getView()->addErrorMessage('Please fill out all fields!');
         $this->addLesson();
     } else {
         $courseId = $this->secureString($_GET['id']);
         $nameEN = $this->secureString($_POST['nameEN']);
         $nameDE = $this->secureString($_POST['nameDE']);
         $points = $this->secureString($_POST['points']);
         if (Lesson::createLesson($courseId, $nameEN, $nameDE, $points)) {
             $this->getView()->addSuccessMessage('Lesson was successfully added.');
         } else {
             $this->getView()->addErrorMessage('Lesson could not be added!');
         }
         $this->defaultAction();
         // create default tutorial page
         $newLesson = Lesson::getNewestLesson($courseId);
         $lessonId = $newLesson->getId();
         $filePath = PAGE_DIR . "lessons/{$courseId}-{$lessonId}.html";
         FileFunctions::createFile($filePath, "New lesson <strong>" . $newLesson->getName('en') . "</strong>");
     }
 }