class.ilObjForum.php

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<?php
/* Copyright (c) 1998-2012 ILIAS open source, Extended GPL, see docs/LICENSE */
 
require_once 'Services/Object/classes/class.ilObject.php';
require_once 'Modules/Forum/classes/class.ilForum.php';
require_once 'Modules/Forum/classes/class.ilFileDataForum.php';
require_once 'Modules/Forum/classes/class.ilForumProperties.php';
 
class ilObjForum extends ilObject
{
        public $Forum;
 
//      private $objProperties = null;
 
        protected static $obj_id_to_forum_id_cache = array();
 
        protected static $ref_id_to_forum_id_cache = array();
 
        protected static $forum_statistics_cache = array();
 
        protected static $forum_last_post_cache = array();
 
        public function __construct($a_id = 0, $a_call_by_reference = true)
        {
                $this->type = 'frm';
                parent::__construct($a_id, $a_call_by_reference);
 
                /*
                 * this constant is used for the information if a single post is marked as new
                 * All threads/posts created before this date are never marked as new
                 * Default is 8 weeks
                 *
                 */
                $new_deadline = time() - 60 * 60 * 24 * 7 * ($this->ilias->getSetting('frm_store_new') ?
                        $this->ilias->getSetting('frm_store_new') :
                        8);
                define('NEW_DEADLINE', $new_deadline);
 
                // TODO: needs to rewrite scripts that are using Forum outside this class
                $this->Forum = new ilForum();
        }
 
        public function create()
        {
                $id = parent::create();
 
                require_once 'Modules/Forum/classes/class.ilForumProperties.php';
                $properties = ilForumProperties::getInstance($this->getId());
                $properties->setDefaultView(1);
                $properties->setAnonymisation(0);
                $properties->setStatisticsStatus(0);
                $properties->setPostActivation(0);
                $properties->setThreadSorting(0);
                $properties->insert();
 
                $this->createSettings();
 
                $this->saveData();
 
                return $id;
        }
 
        public function setPermissions($a_ref_id)
        {
                global $rbacadmin;
 
                parent::setPermissions($a_ref_id);
 
                // ...finally assign moderator role to creator of forum object
                $roles  = array(ilObjForum::_lookupModeratorRole($this->getRefId()));
                $rbacadmin->assignUser($roles[0], $this->getOwner(), 'n');
                $this->updateModeratorRole($roles[0]);
        }
 
        public function updateModeratorRole($role_id)
        {
                global $ilDB;
 
                $ilDB->manipulate('UPDATE frm_data SET top_mods = ' . $ilDB->quote($role_id, 'integer') . ' WHERE top_frm_fk = ' . $ilDB->quote($this->getId(), 'integer'));
        }
 
        function getDiskUsage()
        {
                require_once("./Modules/File/classes/class.ilObjFileAccess.php");
                return ilObjForumAccess::_lookupDiskUsage($this->id);
        }
 
        public static function _lookupThreadSubject($a_thread_id)
        {
                global $ilDB;
 
                $res = $ilDB->queryf('
                        SELECT thr_subject FROM frm_threads WHERE thr_pk = %s',
                        array('integer'), array($a_thread_id));
 
                while($row = $ilDB->fetchObject($res))
                {
                        return $row->thr_subject;
                }
                return '';
        }
 
        // METHODS FOR UN-READ STATUS
        public function getCountUnread($a_usr_id, $a_thread_id = 0)
        {
//              return $this->_getCountUnread($this->getId(),$a_usr_id,$a_thread_id);
//      }
//
//      function _getCountUnread($a_frm_id, $a_usr_id,$a_thread_id = 0)
//      {
 
                $a_frm_id = $this->getId();
 
                global $ilBench, $ilDB;
 
                $ilBench->start("Forum", 'getCountRead');
                if(!$a_thread_id)
                {
                        // Get topic_id
                        $res = $ilDB->queryf('
                                SELECT top_pk FROM frm_data WHERE top_frm_fk = %s',
                                array('integer'), array($a_frm_id));
 
 
                        while($row = $ilDB->fetchObject($res))
                        {
                                $topic_id = $row->top_pk;
                        }
 
                        // Get number of posts
                        $res = $ilDB->queryf('
                                SELECT COUNT(pos_pk) num_posts FROM frm_posts 
                                WHERE pos_top_fk = %s',
                                array('integer'), array($topic_id));
 
                        while($row = $ilDB->fetchObject($res))
                        {
                                $num_posts = $row->num_posts;
                        }
 
                        $res = $ilDB->queryf('
                                SELECT COUNT(post_id) count_read FROM frm_user_read
                                WHERE obj_id = %s
                                AND usr_id = %s',
                                array('integer', 'integer'), array($a_frm_id, $a_usr_id));
 
                        while($row = $ilDB->fetchObject($res))
                        {
                                $count_read = $row->count_read;
                        }
                        $unread = $num_posts - $count_read;
 
                        $ilBench->stop("Forum", 'getCountRead');
                        return $unread > 0 ? $unread : 0;
                }
                else
                {
                        $res = $ilDB->queryf('
                                SELECT COUNT(pos_pk) num_posts FROM frm_posts
                                WHERE pos_thr_fk = %s',
                                array('integer'), array($a_thread_id));
 
                        $row       = $ilDB->fetchObject($res);
                        $num_posts = $row->num_posts;
 
                        $res = $ilDB->queryf('
                                SELECT COUNT(post_id) count_read FROM frm_user_read 
                                WHERE obj_id = %s
                                AND usr_id = %s
                                AND thread_id = %s',
                                array('integer', 'integer', 'integer'), array($a_frm_id, $a_frm_id, $a_thread_id));
 
                        $row        = $ilDB->fetchObject($res);
                        $count_read = $row->count_read;
 
                        $unread = $num_posts - $count_read;
 
                        $ilBench->stop("Forum", 'getCountRead');
                        return $unread > 0 ? $unread : 0;
                }
                $ilBench->stop("Forum", 'getCountRead');
                return false;
        }
 
 
        public function markThreadRead($a_usr_id, $a_thread_id)
        {
                global $ilDB;
 
                // Get all post ids
                $res = $ilDB->queryf('
                        SELECT * FROM frm_posts WHERE pos_thr_fk = %s',
                        array('integer'), array($a_thread_id));
 
                while($row = $ilDB->fetchObject($res))
                {
                        $this->markPostRead($a_usr_id, $a_thread_id, $row->pos_pk);
                }
                return true;
        }
 
        public function markAllThreadsRead($a_usr_id)
        {
                global $ilDB;
 
                $res = $ilDB->queryf('
                        SELECT * FROM frm_data, frm_threads 
                        WHERE top_frm_fk = %s
                        AND top_pk = thr_top_fk',
                        array('integer'), array($this->getId()));
 
                while($row = $ilDB->fetchObject($res))
                {
                        $this->markThreadRead($a_usr_id, $row->thr_pk);
                }
 
                return true;
        }
 
 
        public function markPostRead($a_usr_id, $a_thread_id, $a_post_id)
        {
                global $ilDB;
 
                // CHECK IF ENTRY EXISTS
                $res = $ilDB->queryf('
                        SELECT * FROM frm_user_read 
                        WHERE usr_id = %s
                        AND obj_id = %s
                        AND thread_id = %s
                        AND post_id = %s',
                        array('integer', 'integer', 'integer', 'integer'),
                        array($a_usr_id, $this->getId(), $a_thread_id, $a_post_id));
 
                if($ilDB->numRows($res))
                {
                        return true;
                }
 
                $res = $ilDB->manipulateF('
                        INSERT INTO frm_user_read
                        (       usr_id,
                                obj_id,
                                thread_id,
                                post_id
                        )
                        VALUES (%s,%s,%s,%s)',
                        array('integer', 'integer', 'integer', 'integer'),
                        array($a_usr_id, $this->getId(), $a_thread_id, $a_post_id));
 
                return true;
        }
 
        public function markPostUnread($a_user_id, $a_post_id)
        {
                global $ilDB;
 
                $res = $ilDB->manipulateF('
                        DELETE FROM frm_user_read
                        WHERE usr_id = %s
                        AND post_id = %s',
                        array('integer', 'integer'),
                        array($a_user_id, $a_post_id));
        }
 
        public function isRead($a_usr_id, $a_post_id)
        {
                global $ilDB;
 
                $res = $ilDB->queryf('
                        SELECT * FROM frm_user_read
                        WHERE usr_id = %s
                        AND post_id = %s',
                        array('integer', 'integer'),
                        array($a_usr_id, $a_post_id));
 
                return $ilDB->numRows($res) ? true : false;
        }
 
        public function updateLastAccess($a_usr_id, $a_thread_id)
        {
                global $ilDB;
 
                $res = $ilDB->queryf('
                        SELECT * FROM frm_thread_access 
                        WHERE usr_id = %s
                        AND obj_id = %s
                        AND thread_id = %s',
                        array('integer', 'integer', 'integer'),
                        array($a_usr_id, $this->getId(), $a_thread_id));
                $data = $ilDB->fetchAssoc($res);
 
                $ilDB->replace(
                        'frm_thread_access',
                        array(
                                'usr_id'    => array('integer', $a_usr_id),
                                'obj_id'    => array('integer', $this->getId()),
                                'thread_id' => array('integer', $a_thread_id)
                        ),
                        array(
                                'access_last'   => array('integer', time()),
                                'access_old'    => array('integer', isset($data['access_old']) ? $data['access_old'] : 0),
                                'access_old_ts' => array('timestamp', $data['access_old_ts'])
                        )
                );
 
                return true;
        }
 
        public static function _updateOldAccess($a_usr_id)
        {
                global $ilDB, $ilias;
 
                $ilDB->manipulateF('
                        UPDATE frm_thread_access 
                        SET access_old = access_last
                        WHERE usr_id = %s',
                        array('integer'), array($a_usr_id));
 
                $set = $ilDB->query("SELECT * FROM frm_thread_access " .
                                " WHERE usr_id = " . $ilDB->quote($a_usr_id, "integer")
                );
                while($rec = $ilDB->fetchAssoc($set))
                {
                        $ilDB->manipulate("UPDATE frm_thread_access SET " .
                                        " access_old_ts = " . $ilDB->quote(date('Y-m-d H:i:s', $rec["access_old"]), "timestamp") .
                                        " WHERE usr_id = " . $ilDB->quote($rec["usr_id"], "integer") .
                                        " AND obj_id = " . $ilDB->quote($rec["obj_id"], "integer") .
                                        " AND thread_id = " . $ilDB->quote($rec["thread_id"], "integer")
                        );
                }
 
                $new_deadline = time() - 60 * 60 * 24 * 7 * ($ilias->getSetting('frm_store_new') ?
                        $ilias->getSetting('frm_store_new') :
                        8);
 
                $ilDB->manipulateF('
                        DELETE FROM frm_thread_access WHERE access_last < %s',
                        array('integer'), array($new_deadline));
        }
 
        function _deleteUser($a_usr_id)
        {
                global $ilDB;
 
                $data = array($a_usr_id);
 
                $res = $ilDB->manipulateF('
                        DELETE FROM frm_user_read WHERE usr_id = %s',
                        array('integer'), $data
                );
 
                $res = $ilDB->manipulateF('
                        DELETE FROM frm_thread_access WHERE usr_id = %s',
                        array('integer'), $data
                );
 
                // delete notifications of deleted user
                $ilDB->manipulateF('
                        DELETE FROM frm_notification WHERE user_id = %s',
                        array('integer'), $data);
 
                return true;
        }
 
 
        function _deleteReadEntries($a_post_id)
        {
                global $ilDB;
 
                $statement = $ilDB->manipulateF('
                        DELETE FROM frm_user_read WHERE post_id = %s',
                        array('integer'), array($a_post_id));
 
                return true;
        }
 
        function _deleteAccessEntries($a_thread_id)
        {
                global $ilDB;
 
                $statement = $ilDB->manipulateF('
                        DELETE FROM frm_thread_access WHERE thread_id = %s',
                        array('integer'), array($a_thread_id));
 
                return true;
        }
 
        function update()
        {
                global $ilDB;
 
                if(parent::update())
                {
 
                        $statement = $ilDB->manipulateF('
                                UPDATE frm_data 
                                SET top_name = %s,
                                        top_description = %s,
                                        top_update = %s,
                                        update_user = %s
                                WHERE top_frm_fk =%s',
                                array('text', 'text', 'timestamp', 'integer', 'integer'),
                                array(
                                        $this->getTitle(),
                                        $this->getDescription(),
                                        date("Y-m-d H:i:s"),
                                        (int)$_SESSION["AccountId"],
                                        (int)$this->getId()
                                ));
 
                        return true;
                }
 
                return false;
        }
 
        public function cloneObject($a_target_id, $a_copy_id = 0)
        {
                global $ilDB;
 
                $new_obj = parent::cloneObject($a_target_id, $a_copy_id);
                $this->cloneAutoGeneratedRoles($new_obj);
 
                ilForumProperties::getInstance($this->getId())->copy($new_obj->getId());
                $this->Forum->setMDB2WhereCondition('top_frm_fk = %s ', array('integer'), array($this->getId()));
                $topData = $this->Forum->getOneTopic();
 
                $ilDB->update('frm_data', array(
                        'top_name'        => array('text', $topData['top_name']),
                        'top_description' => array('text', $topData['top_description']),
                        'top_num_posts'   => array('integer', $topData['top_num_posts']),
                        'top_num_threads' => array('integer', $topData['top_num_threads']),
                        'top_last_post'   => array('text', $topData['top_last_post']),
                        'top_date'        => array('timestamp', $topData['top_date']),
                        'visits'          => array('integer', $topData['visits']),
                        'top_update'      => array('timestamp', $topData['top_update']),
                        'update_user'     => array('integer', $topData['update_user']),
                        'top_usr_id'      => array('integer', $topData['top_usr_id'])
                ), array(
                        'top_frm_fk'      => array('integer', $new_obj->getId())
                ));
 
                // read options
                include_once('Services/CopyWizard/classes/class.ilCopyWizardOptions.php');
 
                $cwo     = ilCopyWizardOptions::_getInstance($a_copy_id);
                $options = $cwo->getOptions($this->getRefId());
 
                $options['threads'] = $this->Forum->_getThreads($this->getId());
 
                // Generate starting threads
                include_once('Modules/Forum/classes/class.ilFileDataForum.php');
 
                $new_frm = $new_obj->Forum;
                $new_frm->setMDB2WhereCondition('top_frm_fk = %s ', array('integer'), array($new_obj->getId()));
 
                $new_frm->setForumId($new_obj->getId());
                $new_frm->setForumRefId($new_obj->getRefId());
 
                $new_topic = $new_frm->getOneTopic();
                foreach($options['threads'] as $thread_id=> $thread_subject)
                {
                        $this->Forum->setMDB2WhereCondition('thr_pk = %s ', array('integer'), array($thread_id));
 
                        $old_thread = $this->Forum->getOneThread();
 
                        $old_post_id = $this->Forum->getFirstPostByThread($old_thread['thr_pk']);
                        $old_post    = $this->Forum->getOnePost($old_post_id);
 
                        // Now create new thread and first post
                        
                        $new_post = $new_frm->generateThread(
                                $new_topic['top_pk'],
                                $old_thread['thr_author_id'],
                                $old_thread['thr_display_user_id'],
                                $old_thread['thr_subject'],
                                ilForum::_lookupPostMessage($old_post_id),
                                $old_post['notify'],
                                0,
                                $old_thread['thr_usr_alias'],
                                $old_thread['thr_date']);
                        // Copy attachments
                        $old_forum_files = new ilFileDataForum($this->getId(), $old_post_id);
                        $old_forum_files->ilClone($new_obj->getId(), $new_post);
                }
 
                return $new_obj;
        }
 
        public function cloneAutoGeneratedRoles($new_obj)
        {
                global $ilLog, $rbacadmin;
 
                $moderator     = ilObjForum::_lookupModeratorRole($this->getRefId());
                $new_moderator = ilObjForum::_lookupModeratorRole($new_obj->getRefId());
 
                if(!$moderator || !$new_moderator || !$this->getRefId() || !$new_obj->getRefId())
                {
                        $ilLog->write(__METHOD__ . ' : Error cloning auto generated role: il_frm_moderator');
                }
                $rbacadmin->copyRolePermissions($moderator, $this->getRefId(), $new_obj->getRefId(), $new_moderator, true);
                $ilLog->write(__METHOD__ . ' : Finished copying of role il_frm_moderator.');
 
                include_once './Modules/Forum/classes/class.ilForumModerators.php';
                $obj_mods = new ilForumModerators($this->getRefId());
 
                $old_mods = $obj_mods->getCurrentModerators();
                foreach($old_mods as $user_id)
                {
                        // The object owner is already member of the moderator role when this method is called
                        // Since the new static caches are introduced with ILIAS 5.0, a database error occurs if we try to assign the user here.
                        if($this->getOwner() != $user_id)
                        {
                                $rbacadmin->assignUser($new_moderator, $user_id);
                        }
                }
        }
 
        public function delete()
        {
                global $ilDB;
 
                // always call parent delete function first!!
                if(!parent::delete())
                {
                        return false;
                }
 
                // delete attachments
                $tmp_file_obj =& new ilFileDataForum($this->getId());
                $tmp_file_obj->delete();
                unset($tmp_file_obj);
 
                $this->Forum->setMDB2WhereCondition('top_frm_fk = %s ', array('integer'), array($this->getId()));
 
                $topData = $this->Forum->getOneTopic();
 
                $threads = $this->Forum->getAllThreads($topData['top_pk']);
                foreach($threads['items'] as $thread)
                {
                        $thread_ids_to_delete[$thread->getId()] = $thread->getId();
                }
                
                // delete tree
                $ilDB->manipulate('DELETE FROM frm_posts_tree WHERE '. $ilDB->in('thr_fk', $thread_ids_to_delete, false, 'integer'));
                
                // delete posts
                $ilDB->manipulate('DELETE FROM frm_posts WHERE '. $ilDB->in('pos_thr_fk', $thread_ids_to_delete, false, 'integer'));
                
                // delete threads
                $ilDB->manipulate('DELETE FROM frm_threads WHERE '. $ilDB->in('thr_pk', $thread_ids_to_delete, false, 'integer'));
                
                $obj_id = array($this->getId());
                // delete forum
                $ilDB->manipulateF('DELETE FROM frm_data WHERE top_frm_fk = %s',
                        array('integer'), $obj_id);
                
                // delete settings
                $ilDB->manipulateF('DELETE FROM frm_settings WHERE obj_id = %s',
                        array('integer'), $obj_id);
                
                // delete read infos
                $ilDB->manipulateF('DELETE FROM frm_user_read WHERE obj_id = %s',
                        array('integer'), $obj_id);
                
                // delete thread access entries
                $ilDB->manipulateF('DELETE FROM frm_thread_access WHERE obj_id = %s',
                        array('integer'), $obj_id);
                
                //delete thread notifications
                $ilDB->manipulate('DELETE FROM frm_notification WHERE '. $ilDB->in('thread_id', $thread_ids_to_delete, false, 'integer'));
                
                //delete forum notifications
                $ilDB->manipulateF('DELETE FROM frm_notification WHERE  frm_id = %s', array('integer'), $obj_id);
                
                // delete posts_deleted entries 
                $ilDB->manipulateF('DELETE FROM frm_posts_deleted WHERE obj_id = %s', array('integer'), $obj_id);
 
                return true;
        }
 
        public function initDefaultRoles()
        {
                include_once './Services/AccessControl/classes/class.ilObjRole.php';
                $role = ilObjRole::createDefaultRole(
                                'il_frm_moderator_'.$this->getRefId(),
                                "Moderator of forum obj_no.".$this->getId(),
                                'il_frm_moderator',
                                $this->getRefId()
                );
                return array();
        }
 
        public static function _lookupModeratorRole($a_ref_id)
        {
                global $ilDB;
 
                $mod_title = 'il_frm_moderator_' . $a_ref_id;
 
                $res = $ilDB->queryf('
                        SELECT * FROM object_data WHERE title = %s',
                        array('text'), array($mod_title));
 
                while($row = $ilDB->fetchObject($res))
                {
                        return $row->obj_id;
                }
                return 0;
        }
 
 
        public function createSettings()
        {
                // news settings (public notifications yes/no)
                include_once("./Services/News/classes/class.ilNewsItem.php");
                $default_visibility = ilNewsItem::_getDefaultVisibilityForRefId($_GET["ref_id"]);
                if($default_visibility == "public")
                {
                        ilBlockSetting::_write("news", "public_notifications", 1, 0, $this->getId());
                }
 
                return true;
        }
 
        public function saveData($a_roles = array())
        {
                global $ilUser, $ilDB;
 
                $nextId = $ilDB->nextId('frm_data');
 
                $top_data = array(
                        'top_frm_fk'           => $this->getId(),
                        'top_name'             => $this->getTitle(),
                        'top_description'      => $this->getDescription(),
                        'top_num_posts'        => 0,
                        'top_num_threads'      => 0,
                        'top_last_post'        => NULL,
                        'top_mods'             => !is_numeric($a_roles[0]) ? 0 : $a_roles[0],
                        'top_usr_id'           => $ilUser->getId(),
                        'top_date'             => ilUtil::now()
                );
 
                $ilDB->manipulateF('
                INSERT INTO frm_data 
                ( 
                        top_pk,
                        top_frm_fk, 
                        top_name,
                        top_description,
                        top_num_posts,
                        top_num_threads,
                        top_last_post,
                        top_mods,
                        top_date,
                        top_usr_id
                )
                VALUES(%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)',
                        array('integer', 'integer', 'text', 'text', 'integer', 'integer', 'text', 'integer', 'timestamp', 'integer'),
                        array(
                                $nextId,
                                $top_data['top_frm_fk'],
                                $top_data['top_name'],
                                $top_data['top_description'],
                                $top_data['top_num_posts'],
                                $top_data['top_num_threads'],
                                $top_data['top_last_post'],
                                $top_data['top_mods'],
                                $top_data['top_date'],
                                $top_data['top_usr_id']
                        ));
        }
 
        public function setThreadSorting($a_thr_pk, $a_sorting_value)
        {
                global $ilDB;
 
                $ilDB->update('frm_threads',
                        array('thread_sorting' => array('integer',$a_sorting_value)),
                        array('thr_pk' => array('integer', $a_thr_pk)));
        }
 
 
        public static function lookupForumIdByObjId($obj_id)
        {
                if(array_key_exists($obj_id, self::$obj_id_to_forum_id_cache))
                {
                        return (int)self::$obj_id_to_forum_id_cache[$obj_id];
                }
 
                self::preloadForumIdsByObjIds(array($obj_id));
 
                return (int)self::$obj_id_to_forum_id_cache[$obj_id];
        }
 
        public static function lookupForumIdByRefId($ref_id)
        {
                if(array_key_exists($ref_id, self::$ref_id_to_forum_id_cache))
                {
                        return (int)self::$ref_id_to_forum_id_cache[$ref_id];
                }
 
                self::preloadForumIdsByRefIds(array($ref_id));
 
                return (int)self::$ref_id_to_forum_id_cache[$ref_id];
        }
 
        public static function preloadForumIdsByObjIds(array $obj_ids)
        {
                global $ilDB;
 
                if(count($obj_ids) == 1)
                {
                        $in = " objr.obj_id = " . $ilDB->quote(current($obj_ids), 'integer') . " ";
                }
                else
                {
                        $in = $ilDB->in('objr.obj_id', $obj_ids, false, 'integer');
                }
                $query = "
                        SELECT frmd.top_pk, objr.ref_id, objr.obj_id
                        FROM object_reference objr
                        INNER JOIN frm_data frmd ON frmd.top_frm_fk = objr.obj_id
                        WHERE $in 
                ";
                $res   = $ilDB->query($query);
 
                // Prepare  cache array
                foreach($obj_ids as $obj_id)
                {
                        self::$obj_id_to_forum_id_cache[$obj_id] = null;
                }
 
                while($row = $ilDB->fetchAssoc($res))
                {
                        self::$obj_id_to_forum_id_cache[$row['obj_id']] = $row['top_pk'];
                        self::$ref_id_to_forum_id_cache[$row['ref_id']] = $row['top_pk'];
                }
        }
 
        public static function preloadForumIdsByRefIds(array $ref_ids)
        {
                global $ilDB;
 
                if(count($ref_ids) == 1)
                {
                        $in = " objr.ref_id = " . $ilDB->quote(current($ref_ids), 'integer') . " ";
                }
                else
                {
                        $in = $ilDB->in('objr.ref_id', $ref_ids, false, 'integer');
                }
                $query = "
                        SELECT frmd.top_pk, objr.ref_id, objr.obj_id
                        FROM object_reference objr
                        INNER JOIN frm_data frmd ON frmd.top_frm_fk = objr.obj_id
                        WHERE $in 
                ";
                $res   = $ilDB->query($query);
 
                // Prepare  cache array
                foreach($ref_ids as $ref_id)
                {
                        self::$ref_id_to_forum_id_cache[$ref_id] = null;
                }
 
                while($row = $ilDB->fetchAssoc($res))
                {
                        self::$obj_id_to_forum_id_cache[$row['obj_id']] = $row['top_pk'];
                        self::$ref_id_to_forum_id_cache[$row['ref_id']] = $row['top_pk'];
                }
        }
 
        public static function lookupStatisticsByRefId($ref_id)
        {
                global $ilAccess, $ilUser, $ilDB, $ilSetting;
 
                if(isset(self::$forum_statistics_cache[$ref_id]))
                {
                        return self::$forum_statistics_cache[$ref_id];
                }
 
                $statistics = array(
                        'num_posts'        => 0,
                        'num_unread_posts' => 0,
                        'num_new_posts'    => 0
                );
 
                $forumId = self::lookupForumIdByRefId($ref_id);
                if(!$forumId)
                {
                        self::$forum_statistics_cache[$ref_id] = $statistics;
                        return self::$forum_statistics_cache[$ref_id];
                }
                
                $objProperties = ilForumProperties::getInstance(ilObject::_lookupObjectId($ref_id));
                $is_post_activation_enabled = $objProperties->isPostActivationEnabled();
 
                $act_clause = '';
 
                if($is_post_activation_enabled && !$ilAccess->checkAccess('moderate_frm', '', $ref_id))
                {
                        $act_clause .= " AND (frm_posts.pos_status = " . $ilDB->quote(1, "integer") . " OR frm_posts.pos_author_id = " . $ilDB->quote($ilUser->getId(), "integer") . ") ";
                }
 
                $new_deadline = date('Y-m-d H:i:s', time() - 60 * 60 * 24 * 7 * ($ilSetting->get('frm_store_new') ? $ilSetting->get('frm_store_new') : 8));
 
                if(!$ilUser->isAnonymous())
                {
                        $query = "
                                (SELECT COUNT(frm_posts.pos_pk) cnt
                                FROM frm_posts
                                INNER JOIN frm_threads ON frm_posts.pos_thr_fk = frm_threads.thr_pk 
                                WHERE frm_threads.thr_top_fk = %s $act_clause)
                                
                                UNION ALL
                                 
                                (SELECT COUNT(DISTINCT(frm_user_read.post_id)) cnt
                                FROM frm_user_read
                                INNER JOIN frm_posts ON frm_user_read.post_id = frm_posts.pos_pk
                                INNER JOIN frm_threads ON frm_threads.thr_pk = frm_posts.pos_thr_fk 
                                WHERE frm_user_read.usr_id = %s AND frm_posts.pos_top_fk = %s $act_clause)
                        ";
 
                        $types  = array('integer', 'integer', 'integer'); 
                        $values = array($forumId, $ilUser->getId(), $forumId);
 
                        $forum_overview_setting = (int)$ilSetting::_lookupValue('frma', 'forum_overview');
                        if($forum_overview_setting == ilForumProperties::FORUM_OVERVIEW_WITH_NEW_POSTS)
                        {
                                $news_types = array('integer', 'integer', 'integer', 'timestamp', 'integer');
                                $news_values = array($ilUser->getId(), $ilUser->getId(), $forumId,  $new_deadline, $ilUser->getId());
 
                                $query .= " 
                                UNION ALL
                                
                                (SELECT COUNT(frm_posts.pos_pk) cnt
                                FROM frm_posts
                                LEFT JOIN frm_user_read ON (post_id = frm_posts.pos_pk AND frm_user_read.usr_id = %s)
                                LEFT JOIN frm_thread_access ON (frm_thread_access.thread_id = frm_posts.pos_thr_fk AND frm_thread_access.usr_id = %s)
                                WHERE frm_posts.pos_top_fk = %s
                                AND ( (frm_posts.pos_update > frm_thread_access.access_old_ts)
                                                OR (frm_thread_access.access_old IS NULL AND frm_posts.pos_update > %s)
                                        )
                                AND frm_posts.pos_author_id != %s 
                                AND frm_user_read.usr_id IS NULL $act_clause)";
                                
                                $types  = array_merge($types, $news_types);
                                $values = array_merge($values, $news_values);  
                        }       
                        
                        $mapping = array_keys($statistics);
                        $res     = $ilDB->queryF(
                                $query,
                                $types,
                                $values
                        );
                        for($i = 0; $i <= 2; $i++)
                        {
                                $row = $ilDB->fetchAssoc($res);
 
                                $statistics[$mapping[$i]] = (int)$row['cnt'];
 
                                if($i == 1)
                                {
                                        // unread = all - read
                                        $statistics[$mapping[$i]] = $statistics[$mapping[$i - 1]] - $statistics[$mapping[$i]];
                                }
                        }
                }
                else
                {
                        $query = "
                                SELECT COUNT(frm_posts.pos_pk) cnt
                                FROM frm_posts
                                INNER JOIN frm_threads ON frm_posts.pos_thr_fk = frm_threads.thr_pk 
                                WHERE frm_threads.thr_top_fk = %s $act_clause
                        ";
                        $types  = array('integer');
                        $values = array($forumId);
                        $res     = $ilDB->queryF(
                                $query,
                                $types,
                                $values
                        );
                        $row = $ilDB->fetchAssoc($res);
 
                        $statistics = array(
                                'num_posts'        => $row['cnt'],
                                'num_unread_posts' => $row['cnt'],
                                'num_new_posts'    => $row['cnt']
                        );
                }
 
                self::$forum_statistics_cache[$ref_id] = $statistics;
 
                return self::$forum_statistics_cache[$ref_id];
        }
 
        public static function lookupLastPostByRefId($ref_id)
        {
                global $ilAccess, $ilUser, $ilDB;
 
                if(isset(self::$forum_last_post_cache[$ref_id]))
                {
                        return self::$forum_last_post_cache[$ref_id];
                }
 
                $forumId = self::lookupForumIdByRefId($ref_id);
                if(!$forumId)
                {
                        self::$forum_last_post_cache[$ref_id] = array();
                        return self::$forum_last_post_cache[$ref_id];
                }
 
                $act_clause = '';
                if(!$ilAccess->checkAccess('moderate_frm', '', $ref_id))
                {
                        $act_clause .= " AND (frm_posts.pos_status = " . $ilDB->quote(1, "integer") . " OR frm_posts.pos_author_id = " . $ilDB->quote($ilUser->getId(), "integer") . ") ";
                }
 
                $ilDB->setLimit(1, 0);
                $query = "
                        SELECT *
                        FROM frm_posts 
                        WHERE pos_top_fk = %s $act_clause
                        ORDER BY pos_date DESC
                ";
                $res   = $ilDB->queryF(
                        $query,
                        array('integer'),
                        array($forumId)
                );
 
                $data = $ilDB->fetchAssoc($res);
 
                self::$forum_last_post_cache[$ref_id] = is_array($data) ? $data : array();
 
                return self::$forum_last_post_cache[$ref_id];
        }
 
        public static function getUserIdsOfLastPostsByRefIdAndThreadIds($ref_id, array $thread_ids)
        {
                global $ilUser, $ilAccess, $ilDB;
 
                $act_clause       = '';
                $act_inner_clause = '';
                if(!$ilAccess->checkAccess('moderate_frm', '', $ref_id))
                {
                        $act_clause .= " AND (t1.pos_status = " . $ilDB->quote(1, "integer") . " OR t1.pos_author_id = " . $ilDB->quote($ilUser->getId(), "integer") . ") ";
                        $act_inner_clause .= " AND (t3.pos_status = " . $ilDB->quote(1, "integer") . " OR t3.pos_author_id = " . $ilDB->quote($ilUser->getId(), "integer") . ") ";
                }
 
                $in       = $ilDB->in("t1.pos_thr_fk", $thread_ids, false, 'integer');
                $inner_in = $ilDB->in("t3.pos_thr_fk", $thread_ids, false, 'integer');
//@todo fix this query 'group by ... ' 
                $query = "
                        SELECT t1.pos_display_user_id, t1.update_user
                        FROM frm_posts t1
                        INNER JOIN (
                                SELECT t3.pos_thr_fk, MAX(t3.pos_date) pos_date
                                FROM frm_posts t3
                                WHERE $inner_in $act_inner_clause
                                GROUP BY t3.pos_thr_fk
                        ) t2 ON t2.pos_thr_fk = t1.pos_thr_fk AND t2.pos_date = t1.pos_date
                        WHERE $in $act_clause
                        GROUP BY t1.pos_thr_fk, t1.pos_display_user_id, t1.update_user
                ";
                $usr_ids = array();
 
                $res = $ilDB->query($query);
                while($row = $ilDB->fetchAssoc($res))
                {
                        if((int)$row['pos_display_user_id'])
                        {
                                $usr_ids[] = (int)$row['pos_display_user_id'];
                        }
                        if((int)$row['update_user'])
                        {
                                $usr_ids[] = (int)$row['update_user'];
                        }
                }
 
                return array_unique($usr_ids);
        }
        
        public static function mergeForumUserRead($merge_source_thread_id, $merge_target_thread_id)
        {
                global $ilDB;
                
                $ilDB->update('frm_user_read',
                        array('thread_id' => array('integer', $merge_target_thread_id)),
                        array('thread_id' => array('integer',$merge_source_thread_id)));
        }
}