Modules/Course/classes/class.ilCourseItems.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2001 ILIAS open source, University of Cologne            |
        |                                                                             |
        | This program is free software; you can redistribute it and/or               |
        | modify it under the terms of the GNU General Public License                 |
        | as published by the Free Software Foundation; either version 2              |
        | of the License, or (at your option) any later version.                      |
        |                                                                             |
        | This program is distributed in the hope that it will be useful,             |
        | but WITHOUT ANY WARRANTY; without even the implied warranty of              |
        | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               |
        | GNU General Public License for more details.                                |
        |                                                                             |
        | You should have received a copy of the GNU General Public License           |
        | along with this program; if not, write to the Free Software                 |
        | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
        +-----------------------------------------------------------------------------+
*/


define('IL_CRS_TIMINGS_ACTIVATION',0);
define('IL_CRS_TIMINGS_DEACTIVATED',1);
define('IL_CRS_TIMINGS_PRESETTING',2);

class ilCourseItems
{
        var $course_obj;
        var $ilErr;
        var $ilDB;
        var $tree;
        var $lng;

        var $items;
        var $parent;            // ID OF PARENT CONTAINER e.g course_id, folder_id, group_id

        var $timing_type;
        var $timing_start;
        var $timing_end;


        function ilCourseItems(&$course_obj,$a_parent = 0,$user_id = 0)
        {
                global $ilErr,$ilDB,$lng,$tree;

                $this->ilErr =& $ilErr;
                $this->ilDB  =& $ilDB;
                $this->lng   =& $lng;
                $this->tree  =& $tree;

                $this->course_obj =& $course_obj;
                $this->setParentId($a_parent);
                $this->user_id = $user_id;

                $this->__read();
        }

        public function cloneDependencies($a_target_id,$a_copy_id)
        {
                global $ilObjDataCache,$ilLog;
                
                $ilLog->write(__METHOD__.': Begin course items...');
        
                $target_obj_id = $ilObjDataCache->lookupObjId($a_target_id);
                
                include_once('Services/CopyWizard/classes/class.ilCopyWizardOptions.php');
                $cp_options = ilCopyWizardOptions::_getInstance($a_copy_id);
                $mappings = $cp_options->getMappings();
                
                $query = "SELECT * FROM crs_items WHERE ".
                        "parent_id = ".$this->ilDB->quote($this->getParentId())." ".
                        "ORDER BY position DESC";
                $res = $this->ilDB->query($query);
                
                if(!$res->numRows())
                {
                        $ilLog->write(__METHOD__.': No course items found.');
                        return true;
                }
                
                // new course item object
                if(!is_object($new_container = ilObjectFactory::getInstanceByRefId($a_target_id,false)))
                {
                        $ilLog->write(__METHOD__.': Cannot create target object.');
                        return false;
                }
                $new_items = new ilCourseItems($this->course_obj,$a_target_id);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        if(!isset($mappings[$row->parent_id]) or !$mappings[$row->parent_id])
                        {
                                $ilLog->write(__METHOD__.': No mapping for parent nr. '.$row->parent_id);
                                continue;
                        }
                        if(!isset($mappings[$row->obj_id]) or !$mappings[$row->obj_id])
                        {
                                $ilLog->write(__METHOD__.': No mapping for item nr. '.$row->obj_id);
                                continue;
                        }
                        $new_item_id = $mappings[$row->obj_id];
                        $new_parent = $mappings[$row->parent_id];
                        
                        $new_items->setItemId($new_item_id);
                        $new_items->setParentId($new_parent);
                        $new_items->setTimingType($row->timing_type);
                        $new_items->setTimingStart($row->timing_start);
                        $new_items->setTimingEnd($row->timing_end);
                        $new_items->setSuggestionStart($row->suggestion_start);
                        $new_items->setSuggestionEnd($row->suggestion_end);
                        $new_items->toggleChangeable($row->changeable);
                        $new_items->setEarliestStart($row->earliest_start);
                        $new_items->setLatestEnd($row->latest_end);
                        $new_items->toggleVisible($row->visible);
                        $new_items->setPosition($row->position);
                        $new_items->update($new_item_id);
                        $ilLog->write(__METHOD__.': Added new entry for item nr. '.$row->obj_id);
                }
                $ilLog->write(__METHOD__.': Finished course items.');
        }
        
        public function setItemId($a_item_id)
        {
                $this->item_id = $a_item_id;
        }
        
        public function getItemId()
        {
                return $this->item_id;
        }
        function getUserId()
        {
                global $ilUser;

                return $this->user_id ? $this->user_id : $ilUser->getId();
        }

        function _hasCollectionTimings($a_ref_id)
        {
                global $tree,$ilDB,$ilObjDataCache;

                // get all collections
                include_once 'Services/Tracking/classes/class.ilLPObjSettings.php';

                $obj_id = $ilObjDataCache->lookupObjId($a_ref_id);
                switch(ilLPObjSettings::_lookupMode($obj_id))
                {
                        case LP_MODE_MANUAL_BY_TUTOR:
                        case LP_MODE_COLLECTION:
                                include_once 'Services/Tracking/classes/class.ilLPCollectionCache.php';
                                $ids = ilLPCollectionCache::_getItems($obj_id);
                                break;
                        default:
                                $ids = array($a_ref_id);
                                break;
                }
                if(!$ids)
                {
                        return false;
                }
                
                $query = "SELECT * FROM crs_items ".
                        "WHERE timing_type = ".$ilDB->quote(IL_CRS_TIMINGS_PRESETTING)." ".
                        "AND obj_id IN(".implode(",",ilUtil::quoteArray($ids)).")";

                $res = $ilDB->query($query);
                return $res->numRows() ? true :false;
        }
        
        public function _hasTimings($a_ref_id)
        {
                global $tree,$ilDB;

                $subtree = $tree->getSubTree($tree->getNodeData($a_ref_id));
                
                foreach($subtree as $node)
                {
                        $ref_ids[] = $node['ref_id'];
                }

                $query = "SELECT * FROM crs_items ".
                        "WHERE timing_type = ".$ilDB->quote(IL_CRS_TIMINGS_PRESETTING)." ".
                        "AND obj_id IN(".implode(",",ilUtil::quoteArray($ref_ids)).") ".
                        "AND parent_id IN(".implode(",",ilUtil::quoteArray($ref_ids)).")";

                $res = $ilDB->query($query);
                return $res->numRows() ? true :false;
        }

        function _hasChangeableTimings($a_ref_id)
        {
                global $tree,$ilDB;

                $subtree = $tree->getSubTree($tree->getNodeData($a_ref_id));
                
                foreach($subtree as $node)
                {
                        $ref_ids[] = $node['ref_id'];
                }

                $query = "SELECT * FROM crs_items ".
                        "WHERE timing_type = ".$ilDB->quote(IL_CRS_TIMINGS_PRESETTING)." ".
                        "AND changeable = '1' ".
                        "AND obj_id IN(".implode(",",ilUtil::quoteArray($ref_ids)).") ".
                        "AND parent_id IN(".implode(",",ilUtil::quoteArray($ref_ids)).")";

                $res = $ilDB->query($query);
                return $res->numRows() ? true :false;
        }

        function setParentId($a_parent = 0)
        {
                $this->parent = $a_parent ? $a_parent : $this->course_obj->getRefId();

                $this->__read();
                
                return true;
        }
        function getParentId()
        {
                return $this->parent;
        }

        function setTimingType($a_type)
        {
                $this->timing_type = $a_type;
        }
        function getTimingType()
        {
                return $this->timing_type;
        }
        
        function setTimingStart($a_start)
        {
                $this->timing_start = $a_start;
        }
        function getTimingStart()
        {
                return $this->timing_start;
        }
        function setTimingEnd($a_end)
        {
                $this->timing_end = $a_end;
        }
        function getTimingEnd()
        {
                return $this->timing_end;
        }
        function setSuggestionStart($a_start)
        {
                $this->suggestion_start = $a_start;
        }
        function getSuggestionStart()
        {
                return $this->suggestion_start ? $this->suggestion_start : mktime(0,0,1,date('n',time()),date('j',time()),date('Y',time()));
        }
        function setSuggestionEnd($a_end)
        {
                $this->suggestion_end = $a_end;
        }
        function getSuggestionEnd()
        {
                return $this->suggestion_end ? $this->suggestion_end : mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
        }
        function setEarliestStart($a_start)
        {
                $this->earliest_start = $a_start;
        }
        function getEarliestStart()
        {
                return $this->earliest_start ? $this->earliest_start : mktime(0,0,1,date('n',time()),date('j',time()),date('Y',time()));
        }
        function setLatestEnd($a_end)
        {
                $this->latest_end = $a_end;
        }
        function getLatestEnd()
        {
                return $this->latest_end ? $this->latest_end : mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
        }
        function toggleVisible($a_status)
        {
                $this->visible = (int) $a_status;
        }
        function enabledVisible()
        {
                return (bool) $this->visible;
        }
        function toggleChangeable($a_status)
        {
                $this->changeable = (int) $a_status;
        }
        function enabledChangeable()
        {
                return (bool) $this->changeable;
        }
        
        function setPosition($a_pos)
        {
                $this->position = $a_pos;
        }

        function getAllItems()
        {
                return $this->items ? $this->items : array();
        }

        function getFilteredItems($a_container_id)
        {
                global $objDefinition;
                
                include_once 'Modules/Course/classes/Event/class.ilEventItems.php';

                $event_items = ilEventItems::_getItemsOfContainer($a_container_id);

                foreach($this->items as $item)
                {
                        if(!in_array($item['ref_id'],$event_items) &&
                                !$objDefinition->isSideBlock($item['type']))
                        {
                                $filtered[] = $item;
                        }
                }
                return $filtered ? $filtered : array();
        } 

        function getItemsByEvent($a_event_id)
        {
                include_once 'Modules/Course/classes/Event/class.ilEventItems.php';

                $event_items_obj = new ilEventItems($a_event_id);
                $event_items = $event_items_obj->getItems();
                foreach($event_items as $item)
                {
                        if($this->tree->isDeleted($item))
                        {
                                continue;
                        }
                        $node = $this->tree->getNodeData($item);
                        $items[] = $this->__getItemData($node);
                }
                return $items ? $items : array();
        }
                

        function getItems()
        {
                global $rbacsystem;

                foreach($this->items as $item)
                {
                        if($item["type"] != "rolf" and
                           ($item["timing_type"] or
                                ($item["timing_start"] <= time() and $item["timing_end"] >= time())))
                        {
                                if($rbacsystem->checkAccess('visible',$item['ref_id']))
                                {
                                        $filtered[] = $item;
                                }
                        }
                }
                return $filtered ? $filtered : array();
        }
        function getItem($a_item_id)
        {
                foreach($this->items as $item)
                {
                        if($item["child"] == $a_item_id)
                        {
                                return $item;
                        }
                }
                return array();
        }

        function validateActivation()
        {
                global $ilErr;
                
                $ilErr->setMessage('');

                if($this->getTimingType() == IL_CRS_TIMINGS_ACTIVATION)
                {
                        if($this->getTimingStart() > $this->getTimingEnd())
                        {
                                $ilErr->appendMessage($this->lng->txt("crs_activation_start_invalid"));
                        }
                }
                if($this->getTimingType() == IL_CRS_TIMINGS_PRESETTING)
                {
                        if($this->getSuggestionEnd() > $this->getLatestEnd())
                        {
                                $ilErr->appendMessage($this->lng->txt('crs_latest_end_not_valid'));
                        }
                }
                // Disabled
                #if($this->getTimingType() == IL_CRS_TIMINGS_PRESETTING and 
                #   $this->enabledChangeable())
                #{
                #       if($this->getSuggestionStart() < $this->getEarliestStart() or
                #          $this->getSuggestionEnd() > $this->getLatestEnd() or
                #          $this->getSuggestionStart() > $this->getLatestEnd() or
                #          $this->getSuggestionEnd() < $this->getEarliestStart())
                #       {
                #               $ilErr->appendMessage($this->lng->txt("crs_suggestion_not_within_activation"));
                #       }
                #}

                if($ilErr->getMessage())
                {
                        return false;
                }
                return true;
        }
        
        public function save()
        {
                global $ilLog;
                
                $query = "INSERT INTO crs_items SET ".
                        "timing_type = ".$ilDB->quote($this->getTimingType()).", ".
                        "timing_start = ".$ilDB->quote($this->getTimingStart()).", ".
                        "timing_end = ".$ilDB->quote($this->getTimingEnd()).", ".
                        "suggestion_start = ".$ilDB->quote($this->getSuggestionStart()).", ".
                        "suggestion_end = ".$ilDB->quote($this->getSuggestionEnd()).", ".
                        "changeable = ".$ilDB->quote($this->enabledChangeable()).", ".
                        "earliest_start = ".$ilDB->quote($this->getEarliestStart()).", ".
                        "latest_end = ".$ilDB->quote($this->getLatestEnd()).", ".
                        "visible = ".$ilDB->quote($this->enabledVisible()).", ".
                        "parent_id = ".$ilDB->quote($this->getParentId()).", ".
                        "obj_id = ".$ilDB->quote($this->getItemId()).", ".
                        "position = ".$this->ilDB->quote($this->position);
                $ilLog->write(__METHOD__.': '.$query);  

                $res = $this->ilDB->query($query);
        }
        

        function update($a_item_id)
        {
                global $ilDB;
                
                $query = "UPDATE crs_items SET ".
                        "timing_type = ".$ilDB->quote($this->getTimingType()).", ".
                        "timing_start = ".$ilDB->quote($this->getTimingStart()).", ".
                        "timing_end = ".$ilDB->quote($this->getTimingEnd()).", ".
                        "suggestion_start = ".$ilDB->quote($this->getSuggestionStart()).", ".
                        "suggestion_end = ".$ilDB->quote($this->getSuggestionEnd()).", ".
                        "changeable = ".$ilDB->quote($this->enabledChangeable()).", ".
                        "earliest_start = ".$ilDB->quote($this->getEarliestStart()).", ".
                        "latest_end = ".$ilDB->quote($this->getLatestEnd()).", ".
                        "visible = ".$ilDB->quote($this->enabledVisible())." ".
                        "WHERE parent_id = ".$ilDB->quote($this->getParentId())." ".
                        "AND obj_id = ".$ilDB->quote($a_item_id)."";

                $res = $this->ilDB->query($query);
                $this->__read();

                return true;
        }


        function moveUp($item_id)
        {
                $this->__updateTop($item_id);
                $this->__read();
                
                return true;
        }
        function moveDown($item_id)
        {
                $this->__updateBottom($item_id);
                $this->__read();

                return true;
        }

        function deleteAllEntries()
        {
                global $ilDB;
                
                $all_items = $this->tree->getChilds($this->parent);

                foreach($all_items as $item)
                {
                        $query = "DELETE FROM crs_items ".
                                "WHERE parent_id = ".$ilDB->quote($item["child"])."";

                        $this->ilDB->query($query);
                }
                $query = "DELETE FROM crs_items ".
                        "WHERE parent_id = ".$ilDB->quote($this->course_obj->getRefId())." ";
                
                $this->ilDB->query($query);

                return true;
        }

        // PRIVATE
        function __read()
        {
                $this->items = array();
                $all_items = $this->tree->getChilds($this->parent);

                foreach($all_items as $item)
                {
                        if($item["type"] != 'rolf')
                        {
                                $this->items[] = $item;
                        }
                }

                for($i = 0;$i < count($this->items); ++$i)
                {
                        if($this->items[$i]["type"] == 'rolf')
                        {
                                unset($this->items[$i]);
                                continue;
                        }
                        $this->items[$i] = $this->__getItemData($this->items[$i]);
                }
                $this->__purgeDeleted();
                $this->__sort();

                return true;
        }

        function __purgeDeleted()
        {
                global $tree,$ilDB;

                $all = array();

                $query = "SELECT obj_id FROM crs_items ".
                        "WHERE parent_id = ".$ilDB->quote($this->getParentId())." ";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        if($tree->getParentId($row->obj_id) != $this->getParentId())
                        {
                                $this->__delete($row->obj_id);
                        }
                }
        }

        function __delete($a_obj_id)
        {
                global $ilDB;
                
                // READ POSITION
                $query = "SELECT position FROM crs_items ".
                        "WHERE obj_id = ".$ilDB->quote($a_obj_id)." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())." ";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $position = $row->position;
                }

                // UPDATE positions
                $query = "UPDATE crs_items SET ".
                        "position = CASE ".
                        "WHEN position > ".$ilDB->quote($position)." ".
                        "THEN position - 1 ".
                        "ELSE position ".
                        "END ".
                        "WHERE parent_id = ".$ilDB->quote($this->getParentId())." ";

                $res = $this->ilDB->query($query);

                // DELETE ENTRY
                $query = "DELETE FROM crs_items ".
                        "WHERE parent_id = ".$ilDB->quote($this->getParentId())." ".
                        "AND obj_id = ".$ilDB->quote($a_obj_id)." ";

                $res = $this->ilDB->query($query);

                return true;
        }
                        
        function __getItemData($a_item)
        {
                global $ilDB,$ilUser,$ilObjDataCache;

                $query = "SELECT * FROM crs_items  ".
                        "WHERE obj_id = ".$ilDB->quote($a_item['child'])." ".
                        "AND parent_id = ".$ilDB->quote($a_item['parent'])." ";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $a_item["timing_type"] = $row->timing_type;
                        $a_item["timing_start"]         = $row->timing_start;
                        $a_item["timing_end"]           = $row->timing_end;
                        $a_item["suggestion_start"]             = $row->suggestion_start ? $row->suggestion_start :
                                mktime(0,0,1,date('n',time()),date('j',time()),date('Y',time()));
                        $a_item["suggestion_end"]               = $row->suggestion_end ? $row->suggestion_end :
                                mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
                        $a_item['changeable']                   = $row->changeable;
                        $a_item['earliest_start']               = $row->earliest_start ? $row->earliest_start :
                                mktime(0,0,1,date('n',time()),date('j',time()),date('Y',time()));
                        $a_item['latest_end']                   = $row->latest_end ? $row->latest_end : 
                                mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
                        $a_item['visible']                              = $row->visible;
                        $a_item["position"]                             = $row->position;

                        include_once 'Modules/Course/classes/Timings/class.ilTimingPlaned.php';
                        $data = ilTimingPlaned::_getPlanedTimings($this->getUserId(),$a_item['child']);

                        // Check for user entry
                        if($a_item['changeable'] and 
                           $a_item['timing_type'] == IL_CRS_TIMINGS_PRESETTING)
                        {
                                if($data['planed_start'])
                                {
                                        $a_item['start'] = $data['planed_start'];
                                        $a_item['end'] = $data['planed_end'];
                                        $a_item['activation_info'] = 'crs_timings_planed_info';
                                }
                                else
                                {
                                        $a_item['start'] = $row->suggestion_start;
                                        $a_item['end'] = $row->suggestion_end;
                                        $a_item['activation_info'] = 'crs_timings_suggested_info';
                                }
                        }
                        elseif($a_item['timing_type'] == IL_CRS_TIMINGS_PRESETTING)
                        {
                                $a_item['start'] = $row->suggestion_start;
                                $a_item['end'] = $row->suggestion_end;
                                $a_item['activation_info'] = 'crs_timings_suggested_info';
                        }
                        elseif($a_item['timing_type'] == IL_CRS_TIMINGS_ACTIVATION)
                        {
                                $a_item['start'] = $row->timing_start;
                                $a_item['end'] = $row->timing_end;
                                $a_item['activation_info'] = 'activation';
                        }
                        else
                        {
                                $a_item['start'] = 999999999;
                        }
                }

                if(!isset($a_item["position"]))
                {
                        $a_item = $this->createDefaultEntry($a_item);
                }
                return $a_item;
        }

        function createDefaultEntry($a_item)
        {
                global $ilDB, $objDefinition;
                
                $a_item["timing_type"] = IL_CRS_TIMINGS_DEACTIVATED;
                $a_item["timing_start"]         = time();
                $a_item["timing_end"]           = time();
                $a_item["suggestion_start"]             = time();
                $a_item["suggestion_end"]               = time();
                if ($objDefinition->isSideBlock($a_item["type"]))
                {
                        $a_item["position"]                             = 0;
                }
                else
                {
                        $a_item["position"]                             = $this->__getLastPosition() + 1;
                }
                $a_item['visible']                              = 0;
                $a_item['changeable']                   = 0;
                $a_item['earliest_start']               = time();
                $a_item['latest_end']           = mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
                $a_item['visible']                              = 0;
                $a_item['changeable']                   = 0;
                

                $query = "INSERT INTO crs_items ".
                        "VALUES(".$ilDB->quote($a_item['parent']).",".
                        $ilDB->quote($a_item["child"]).",".
                        $ilDB->quote($a_item["timing_type"]).",".
                        $ilDB->quote($a_item["timing_start"]).",".
                        $ilDB->quote($a_item["timing_end"]).",".
                        $ilDB->quote($a_item["suggestion_start"]).",".
                        $ilDB->quote($a_item["suggestion_end"]).",".
                        $ilDB->quote($a_item["changeable"]).",".
                        $ilDB->quote($a_item['earliest_start']).", ".
                        $ilDB->quote($a_item['latest_end']).", ".
                        $ilDB->quote($a_item["visible"]).",".
                        $ilDB->quote($a_item["position"]).")";

                $res = $this->ilDB->query($query);

                return $a_item;
        }

        // methods for manual sortation
        function __getLastPosition()
        {
                global $ilDB;
                
                $query = "SELECT MAX(position) as last_position FROM crs_items ".
                        "WHERE parent_id = ".$ilDB->quote($this->getParentId())." ";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $max = $row->last_position;
                }
                return $max ? $max : 0;
        }

        function __updateTop($item_id)
        {
                global $ilDB;
                
                $query = "SELECT position,obj_id FROM crs_items ".
                        "WHERE obj_id = ".$ilDB->quote($item_id)." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())."";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $node_a["position"] = $row->position;
                        $node_a["obj_id"]         = $row->obj_id;
                }

                $query = "SELECT position, obj_id FROM crs_items ".
                        "WHERE position < ".$ilDB->quote($node_a["position"])." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())." ".
                        "ORDER BY position DESC";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        if(!$this->__isMovable($row->obj_id))
                        {
                                continue;
                        }
                        $node_b["position"] = $row->position;
                        $node_b["obj_id"]         = $row->obj_id;
                        break;
                }
                $this->__switchNodes($node_a,$node_b);
                
        }

        function __updateBottom($item_id)
        {
                global $ilDB;
                
                $query = "SELECT position,obj_id FROM crs_items ".
                        "WHERE obj_id = ".$ilDB->quote($item_id)." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())."";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $node_a["position"] = $row->position;
                        $node_a["obj_id"]         = $row->obj_id;
                        break;
                }
                $query = "SELECT position ,obj_id FROM crs_items ".
                        "WHERE position > ".$ilDB->quote($node_a["position"])." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())." ".
                        "ORDER BY position ASC";

                $res = $this->ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        if(!$this->__isMovable($row->obj_id))
                        {
                                continue;
                        }
                        $node_b["position"] = $row->position;
                        $node_b["obj_id"]         = $row->obj_id;
                        break;
                }
                $this->__switchNodes($node_a,$node_b);

                return true;
        }

        function __isMovable($a_ref_id)
        {
                include_once 'Modules/Course/classes/Event/class.ilEventItems.php';

                global $ilObjDataCache;

                if($ilObjDataCache->lookupType($ilObjDataCache->lookupObjId($a_ref_id)) != 'crs')
                {
                        return true;
                }
                if(ilEventItems::_isAssigned($a_ref_id))
                {
                        return false;
                }
                return true;
        }

        function __switchNodes($node_a,$node_b)
        {
                global $ilDB;
                
                if(!$node_b["obj_id"])
                {
                        return false;
                }

                $query = "UPDATE crs_items SET ".
                        "position = ".$ilDB->quote($node_a["position"])." ".
                        "WHERE obj_id = ".$ilDB->quote($node_b["obj_id"])." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())."";

                $res = $this->ilDB->query($query);

                $query = "UPDATE crs_items SET ".
                        "position = ".$ilDB->quote($node_b["position"])." ".
                        "WHERE obj_id = ".$ilDB->quote($node_a["obj_id"])." ".
                        "AND parent_id = ".$ilDB->quote($this->getParentId())."";

                $res = $this->ilDB->query($query);

                return true;
        }


        function __sort()
        {
                switch($this->course_obj->getOrderType())
                {
                        case IL_CRS_SORT_MANUAL:
                                $this->items = ilUtil::sortArray($this->items,"position","asc",true);
                                break;

                        case IL_CRS_SORT_TITLE:
                                $this->items = ilUtil::sortArray($this->items,"title","asc");
                                break;

                        case IL_CRS_SORT_ACTIVATION:
                                // Sort by starting time. If mode is IL_CRS_TIMINGS_DEACTIVATED then sort these items by title and append
                                // them to the array.
                                list($active,$inactive) = $this->__splitByActivation();
                                
                                $sorted_active = ilUtil::sortArray($active,"start","asc");
                                $sorted_inactive = ilUtil::sortArray($inactive,'title','asc');
                                
                                $this->items = array_merge($sorted_active,$sorted_inactive);
                                break;
                }
                return true;
        }

        function __splitByActivation()
        {
                $inactive = $active = array();
                foreach($this->items as $item)
                {
                        if($item['timing_type'] == IL_CRS_TIMINGS_DEACTIVATED)
                        {
                                $inactive[] = $item;
                        }
                        else
                        {
                                $active[] = $item;
                        }
                }
                return array($active,$inactive);
        }
        // STATIC
        function _getItem($a_item_id)
        {
                include_once 'Modules/Course/classes/class.ilObjCourse.php';

                global $ilDB,$ilUser;

                $query = "SELECT * FROM crs_items ".
                        "WHERE obj_id = '".$a_item_id."'";
                $res = $ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $data['parent_id'] = $row->parent_id;
                        $data['obj_id'] = $row->obj_id;
                        $data['timing_type'] = $row->timing_type;
                        $data['timing_start'] = $row->timing_start;
                        $data['timing_end'] = $row->timing_end;
                        $data["suggestion_start"] = $row->suggestion_start ? $row->suggestion_start :
                                mktime(0,0,1,date('n',time()),date('j',time()),date('Y',time()));
                        $data["suggestion_end"] = $row->suggestion_end ? $row->suggestion_end :
                                mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
                        $data['changeable'] = $row->changeable;
                        $data['earliest_start'] = $row->earliest_start ? $row->earliest_start :
                                mktime(0,0,1,date('n',time()),date('j',time()),date('Y',time()));
                        $data['latest_end'] = $row->latest_end ? $row->latest_end : 
                                mktime(23,55,00,date('n',time()),date('j',time()),date('Y',time()));
                        $data['visible'] = $row->visible;
                        $data['position'] = $row->position;


                        include_once 'Modules/Course/classes/Timings/class.ilTimingPlaned.php';
                        $user_data = ilTimingPlaned::_getPlanedTimings($ilUser->getId(),$data['child']);

                        // Check for user entry
                        if($data['changeable'] and 
                           $data['timing_type'] == IL_CRS_TIMINGS_PRESETTING)
                        {
                                if($user_data['planed_start'])
                                {
                                        $data['start'] = $user_data['planed_start'];
                                        $data['end'] = $user_data['planed_end'];
                                        $data['activation_info'] = 'crs_timings_planed_info';
                                }
                                else
                                {
                                        $data['start'] = $row->suggestion_start;
                                        $data['end'] = $row->suggestion_end;
                                        $data['activation_info'] = 'crs_timings_suggested_info';
                                }
                        }
                        elseif($data['timing_type'] == IL_CRS_TIMINGS_PRESETTING)
                        {
                                $data['start'] = $row->suggestion_start;
                                $data['end'] = $row->suggestion_end;
                                $data['activation_info'] = 'crs_timings_suggested_info';
                        }
                        elseif($data['timing_type'] == IL_CRS_TIMINGS_ACTIVATION)
                        {
                                $data['start'] = $row->timing_start;
                                $data['end'] = $row->timing_end;
                                $data['activation_info'] = 'activation';
                        }
                        else
                        {
                                $data['start'] = 999999999;
                        }
                }
                return $data ? $data : array();
        }

        function _isActivated($a_item_id)
        {
                global $ilDB;

                $query = "SELECT * FROM crs_items ".
                        "WHERE obj_id = ".$ilDB->quote($a_item_id)." ";

                $res = $ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        if($row->activation_unlimited)
                        {
                                return true;
                        }
                        if(time() > $row->activation_start and time() < $row->activation_end)
                        {
                                return true;
                        }
                }
                return false;
        }
        
        public static function _readActivationTimes($a_ref_ids)
        {
                global $ilDB;
                
                if(!is_array($a_ref_ids) or !$a_ref_ids)
                {
                        return array();
                }
                
                $query = "SELECT obj_id,timing_type,timing_start,timing_end,visible FROM crs_items ".
                        "WHERE obj_id IN (".implode(',',ilUtil::quoteArray($a_ref_ids)).")";
                $res = $ilDB->query($query);
                while($row = $res->fetchRow(DB_FETCHMODE_OBJECT))
                {
                        $ac_times[(string) $row->obj_id]['obj_id'] = $row->obj_id;
                        $ac_times[(string) $row->obj_id]['timing_type'] = $row->timing_type;
                        $ac_times[(string) $row->obj_id]['timing_start'] = $row->timing_start;
                        $ac_times[(string) $row->obj_id]['timing_end'] = $row->timing_end;
                        $ac_times[(string) $row->obj_id]['visible'] = $row->visible;
                }

                return $ac_times ? $ac_times : array();
        }
}
?>