17      * @param string|null $user Username, null for no user data
20     public function getLessons($user = null)  argument
26         if ($user !== null) {
27             $lessons = array_merge($lessons, $this->getUserLessons($user));
54      * @param string $user Username
57     public function markLesson($id, $user, $seen = true)  argument
59         if ($user === null) return false;
61         $file = $this->getUserFile($user);
71      * @param string $user
74     public function getUserLessons($user)  argument
76         $file = $this->getUserFile($user);
102     public function getLesson($id, $user)  argument
104         $all = $this->getLessons($user);
112      * @param null|string $user When user is given, next unseen lesson is returned
115     public function getNextLesson($id, $user = null)  argument
117         $all = $this->getLessons($user);
126             if ($user !== null && $all[$keys[$i]] !== 0) {
140      * @param null|string $user When user is given, previous unseen lesson is returned
143     public function getPrevLesson($id, $user = null)  argument
145         $all = $this->getLessons($user);
153             if ($user !== null && $all[$keys[$i]] !== 0) {
167      * @param string $user username
169     protected function getUserFile($user)  argument
174         $user = utf8_encodeFN($user); // make sure the user is clean for directories
175         return $conf['metadir'] . '_lms/' . $user . '.lms';