/**
  * Collect page elements (that need to be exported separately)
  *
  * @param string $a_pg_type page type
  * @param int $a_pg_id page id
  */
 function collectPageElements($a_type, $a_id)
 {
     // collect media objects
     $pg_mobs = ilObjMediaObject::_getMobsOfObject($a_type, $a_id);
     foreach ($pg_mobs as $pg_mob) {
         $this->mobs[$pg_mob] = $pg_mob;
     }
     // collect all files
     include_once "./Modules/File/classes/class.ilObjFile.php";
     $files = ilObjFile::_getFilesOfObject($a_type, $a_id);
     foreach ($files as $f) {
         $this->files[$f] = $f;
     }
     $skill_tree = $ws_tree = null;
     $pcs = ilPageContentUsage::getUsagesOfPage($a_id, $a_type);
     foreach ($pcs as $pc) {
         // skils
         if ($pc["type"] == "skmg") {
             $skill_id = $pc["id"];
             // get user id from portfolio page
             include_once "Services/Portfolio/classes/class.ilPortfolioPage.php";
             $page = new ilPortfolioPage(0, $a_id);
             $user_id = $page->create_user;
             // we only need 1 instance each
             if (!$skill_tree) {
                 include_once "Services/Skill/classes/class.ilSkillTree.php";
                 $skill_tree = new ilSkillTree();
                 include_once "Services/Skill/classes/class.ilPersonalSkill.php";
                 include_once "Services/PersonalWorkspace/classes/class.ilWorkspaceTree.php";
                 $ws_tree = new ilWorkspaceTree($user_id);
             }
             // walk skill tree
             $b_skills = ilSkillTreeNode::getSkillTreeNodes($skill_id, true);
             foreach ($b_skills as $bs) {
                 $skill = ilSkillTreeNodeFactory::getInstance($bs["id"]);
                 $level_data = $skill->getLevelData();
                 foreach ($level_data as $k => $v) {
                     // get assigned materials from personal skill
                     $mat = ilPersonalSkill::getAssignedMaterial($user_id, $bs["tref"], $v["id"]);
                     if (sizeof($mat)) {
                         foreach ($mat as $item) {
                             $wsp_id = $item["wsp_id"];
                             $obj_id = $ws_tree->lookupObjectId($wsp_id);
                             // all possible material types for now
                             switch (ilObject::_lookupType($obj_id)) {
                                 case "file":
                                     $this->files[$obj_id] = $obj_id;
                                     break;
                                 case "tstv":
                                     include_once "Modules/Test/classes/class.ilObjTestVerification.php";
                                     $obj = new ilObjTestVerification($obj_id, false);
                                     $this->files_direct[$obj_id] = array($obj->getFilePath(), $obj->getOfflineFilename());
                                     break;
                                 case "excv":
                                     include_once "Modules/Exercise/classes/class.ilObjExerciseVerification.php";
                                     $obj = new ilObjExerciseVerification($obj_id, false);
                                     $this->files_direct[$obj_id] = array($obj->getFilePath(), $obj->getOfflineFilename());
                                     break;
                             }
                         }
                     }
                 }
             }
         }
     }
 }