Services/News/classes/class.ilNewsItem.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2006 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("NEWS_NOTICE", 0);
define("NEWS_MESSAGE", 1);
define("NEWS_WARNING", 2);

include_once("./Services/News/classes/class.ilNewsItemGen.php");

class ilNewsItem extends ilNewsItemGen
{
        private $limitation;
        
        public function __construct($a_id = 0)
        {
                parent::__construct($a_id);
                $this->limitation = true;
        }

        
        function setLimitation($a_limitation)
        {
                $this->limitation = $a_limitation;
        }

        function getLimitation()
        {
                return $this->limitation;
        }

        function create()
        {
                global $ilDB;
                
                parent::create();
                
                $news_set = new ilSetting("news");
                $max_items = $news_set->get("max_items");
                if ($max_items <= 0)
                {
                        $max_items = 50;
                }
                
                // limit number of news
                if ($this->getLimitation())
                {
                        // Determine how many rows should be deleted
                        $query = "SELECT count(*) AS cnt ".
                                "FROM il_news_item ".
                                "WHERE ".
                                        "context_obj_id = ".$ilDB->quote($this->getContextObjId()).
                                        " AND context_obj_type = ".$ilDB->quote($this->getContextObjType()).
                                        " AND context_sub_obj_id = ".$ilDB->quote($this->getContextSubObjId()).
                                        " AND context_sub_obj_type = ".$ilDB->quote($this->getContextSubObjType());
        
                        $set = $ilDB->query($query);
                        $rec = $set->fetchRow(DB_FETCHMODE_ASSOC);
                                        
                        // if we have more records than allowed, delete them
                        if (($rec["cnt"] > $max_items) && $this->getContextObjId() > 0)
                        {
                                $query = "SELECT * ".
                                        "FROM il_news_item ".
                                        "WHERE ".
                                                "context_obj_id = ".$ilDB->quote($this->getContextObjId()).
                                                " AND context_obj_type = ".$ilDB->quote($this->getContextObjType()).
                                                " AND context_sub_obj_id = ".$ilDB->quote($this->getContextSubObjId()).
                                                " AND context_sub_obj_type = ".$ilDB->quote($this->getContextSubObjType()).
                                                " ORDER BY creation_date ASC".
                                                " LIMIT ".($rec["cnt"] - $max_items);
        
                                $del_set = $ilDB->query($query);
                                while ($del_item = $del_set->fetchRow(DB_FETCHMODE_ASSOC))
                                {
                                        $del_news = new ilNewsItem($del_item["id"]);
                                        $del_news->delete();
                                }
                        }
                }
        }

        static function _getNewsItemsOfUser($a_user_id, $a_only_public = false,
                $a_prevent_aggregation = false, $a_per = 0, &$a_cnt = NULL)
        {
                global $ilAccess, $ilUser, $ilBench;
                
                $ilBench->start("News", "getNewsItemsOfUser");
                
                $news_item = new ilNewsItem();
                $news_set = new ilSetting("news");
                
                $per = $a_per;

                include_once("./Services/News/classes/class.ilNewsSubscription.php");
                include_once("./Services/Block/classes/class.ilBlockSetting.php");
                
                // this is currently not used
                $ilBench->start("News", "getNewsItemsOfUser_getRefIds");
                $ref_ids = ilNewsSubscription::_getSubscriptionsOfUser($a_user_id);
                
                if (ilObjUser::_lookupPref($a_user_id, "pd_items_news") != "n")
                {
                        // this should be the case for all users
                        $pd_items = ilObjUser::_lookupDesktopItems($a_user_id);
                        foreach($pd_items as $item)
                        {
                                if (!in_array($item["ref_id"], $ref_ids))
                                {
                                        $ref_ids[] = $item["ref_id"];
                                }
                        }
                }
                $ilBench->stop("News", "getNewsItemsOfUser_getRefIds");
                
                $data = array();

                foreach($ref_ids as $ref_id)
                {
                        $ilBench->start("News", "getNewsForRefId");
                        if (!$a_only_public)
                        {
                                // this loop should not cost too much performance
                                $ilBench->start("News", "getAggregatedNewsData_getContexts_checkAccess");
                                $acc = $ilAccess->checkAccess("read", "", $ref_id);
                                $ilBench->stop("News", "getAggregatedNewsData_getContexts_checkAccess");
                                
                                if (!$acc)
                                {
                                        continue;
                                }
                        }

                        $ilBench->start("News", "getNewsForRefId_getNews");
                        $obj_id = ilObject::_lookupObjId($ref_id);
                        $obj_type = ilObject::_lookupType($obj_id);
                        $news = $news_item->getNewsForRefId($ref_id, $a_only_public, false,
                                $per, $a_prevent_aggregation);
                        $ilBench->stop("News", "getNewsForRefId_getNews");
                        
                        // counter
                        if (!is_null($a_cnt))
                        {
                                $a_cnt[$ref_id] = count($news);
                        }

                        $ilBench->start("News", "getNewsForRefId_mergeNews");
                        $data = ilNewsItem::mergeNews($data, $news);
                        $ilBench->stop("News", "getNewsForRefId_mergeNews");
                        
                        $ilBench->stop("News", "getNewsForRefId");
                }

                $data = ilUtil::sortArray($data, "creation_date", "desc", false, true);

                $ilBench->stop("News", "getNewsItemsOfUser");
                
//var_dump($data);
                return $data;
        }
        
        function getNewsForRefId($a_ref_id, $a_only_public = false, $a_stopnesting = false,
                $a_time_period = 0, $a_prevent_aggregation = true, $a_forum_group_sequences = false)
        {
                $obj_id = ilObject::_lookupObjId($a_ref_id);
                $obj_type = ilObject::_lookupType($obj_id);
                
                // get starting date
                $starting_date = "";
                if ($obj_type == "grp" || $obj_type == "crs" || $obj_type == "cat")
                {
                        include_once("./Services/Block/classes/class.ilBlockSetting.php");
                        $hide_news_per_date = ilBlockSetting::_lookup("news", "hide_news_per_date",
                                0, $obj_id);
                        if ($hide_news_per_date)
                        {
                                $starting_date = ilBlockSetting::_lookup("news", "hide_news_date",
                                        0, $obj_id);
                        }
                }
                
                if ($obj_type == "cat" && !$a_stopnesting)
                {
                        $news = $this->getAggregatedChildNewsData($a_ref_id, $a_only_public, $a_time_period,
                                $a_prevent_aggregation, $starting_date);
                }
                else if (($obj_type == "grp" || $obj_type == "crs") &&
                        !$a_stopnesting)
                {
                        $news = $this->getAggregatedNewsData($a_ref_id, $a_only_public, $a_time_period,
                                $a_prevent_aggregation, $starting_date);
                }
                else
                {
                        $news_item = new ilNewsItem();
                        $news_item->setContextObjId($obj_id);
                        $news_item->setContextObjType($obj_type);
                        $news = $news_item->queryNewsForContext($a_only_public, $a_time_period,
                                $starting_date);
                        $unset = array();
                        foreach ($news as $k => $v)
                        {
                                if (!$a_only_public || $v["visibility"] == NEWS_PUBLIC ||
                                        ($v["priority"] == 0 &&
                                                ilBlockSetting::_lookup("news", "public_notifications",
                                                0, $obj_id)))
                                {
                                        $news[$k]["ref_id"] = $a_ref_id;
                                }
                                else
                                {
                                        $unset[] = $k;
                                }
                        }
                        foreach ($unset as $un)
                        {
                                unset($news[$un]);
                        }
                }
                
                if (!$a_prevent_aggregation)
                {
                        $news = $this->aggregateForums($news);
                }
                else if ($a_forum_group_sequences)
                {
                        $news = $this->aggregateForums($news, true);
                }
                
                return $news;
        }
        
        function getAggregatedNewsData($a_ref_id, $a_only_public = false, $a_time_period = 0,
                $a_prevent_aggregation = false, $a_starting_date = "")
        {
                global $tree, $ilAccess, $ilBench, $ilObjDataCache;
                
                $ilBench->start("News", "getAggregatedNewsData");
                
                // get news of parent object
                
                $data = array();
                
                // get subtree
                $ilBench->start("News", "getAggregatedNewsData_getSubTree");
                $cur_node = $tree->getNodeData($a_ref_id);

                if ($cur_node["lft"] != "")             // should never be empty
                {
                        $nodes = $tree->getSubTree($cur_node, true);
                }
                else
                {
                        $nodes = array();
                }
                
                // preload object data cache
                $ref_ids = array();
                $obj_ids = array();
                foreach($nodes as $node)
                {
                        $ref_ids[] = $node["child"];
                        $obj_ids[] = $node["obj_id"];
                }
                
                $ilObjDataCache->preloadReferenceCache($ref_ids);
                if (!$a_only_public)
                {
                        $ilAccess->preloadActivationTimes($ref_ids);
                }
                $ilBench->stop("News", "getAggregatedNewsData_getSubTree");
                
                // no check, for which of the objects any news are available
                $news_obj_ids = ilNewsItem::filterObjIdsPerNews($obj_ids, $a_time_period);
                //$news_obj_ids = $obj_ids;
                
                // get news for all subtree nodes
                $ilBench->start("News", "getAggregatedNewsData_getContexts");
                $contexts = array();
                foreach($nodes as $node)
                {
                        // only go on, if news are available
                        if (!in_array($node["obj_id"], $news_obj_ids))
                        {
                                continue;
                        }
                        
                        if (!$a_only_public)
                        {
                                $ilBench->start("News", "getAggregatedNewsData_getContexts_checkAccess");
                                $acc = $ilAccess->checkAccess("read", "", $node["child"]);
                                $ilBench->stop("News", "getAggregatedNewsData_getContexts_checkAccess");
                                
                                if (!$acc)
                                {
                                        continue;
                                }
                        }
                        
                        $ref_id[$node["obj_id"]] = $node["child"];
                        $contexts[] = array("obj_id" => $node["obj_id"],
                                "obj_type" => $node["type"]);
                }
                $ilBench->stop("News", "getAggregatedNewsData_getContexts");
                
                // sort and return
                $news = $this->queryNewsForMultipleContexts($contexts, $a_only_public, $a_time_period,
                        $a_starting_date);
                
                $ilBench->start("News", "getAggregatedNewsData_mergeAndSort");
                
                $to_del = array();
                foreach ($news as $k => $v)
                {
                        $news[$k]["ref_id"] = $ref_id[$v["context_obj_id"]];
                }
                
                $data = ilNewsItem::mergeNews($data, $news);
                $data = ilUtil::sortArray($data, "creation_date", "desc", false, true);
                
                if (!$a_prevent_aggregation)
                {
                        $data = $this->aggregateFiles($data, $a_ref_id);
                }
                
//var_dump($data);
                
                $ilBench->stop("News", "getAggregatedNewsData_mergeAndSort");
                $ilBench->stop("News", "getAggregatedNewsData");
                
                return $data;
        }
        
        function aggregateForums($news, $a_group_posting_sequence = false)
        {
                $to_del = array();
                $forums = array();
                
                // aggregate
                foreach ($news as $k => $v)
                {
                        if ($a_group_posting_sequence && $last_aggregation_forum > 0 &&
                                $last_aggregation_forum != $news[$k]["context_obj_id"])
                        {
                                $forums[$last_aggregation_forum] = "";
                        }

                        if ($news[$k]["context_obj_type"] == "frm")
                        {
                                if ($forums[$news[$k]["context_obj_id"]] == "")
                                {
                                        // $forums[forum_id] = news_id;
                                        $forums[$news[$k]["context_obj_id"]] = $k;
                                        $last_aggregation_forum = $news[$k]["context_obj_id"];
                                }
                                else
                                {
                                        $to_del[] = $k;
                                }
                                
                                $news[$k]["no_context_title"] = true;
                                
                                // aggregate every forum into it's "k" news
                                $news[$forums[$news[$k]["context_obj_id"]]]["aggregation"][$k]
                                        = $news[$k];
                                $news[$k]["agg_ref_id"]
                                        = $news[$k]["ref_id"];
                                $news[$k]["content"] = "";
                                $news[$k]["content_long"] = "";
                        }
                }
                
                // delete double entries
                foreach($to_del as $k)
                {
                        unset($news[$k]);
                }
//var_dump($news[14]["aggregation"]);

                
                return $news;
        }
        
        function aggregateFiles($news, $a_ref_id)
        {
                $first_file = "";
                $to_del = array();
                foreach ($news as $k => $v)
                {
                        // aggregate file related news
                        if ($news[$k]["context_obj_type"] == "file")
                        {
                                if ($first_file == "")
                                {
                                        $first_file = $k;
                                }
                                else
                                {
                                        $to_del[] = $k;
                                }
                                $news[$first_file]["aggregation"][$k] = $news[$k];
                                $news[$first_file]["agg_ref_id"] = $a_ref_id;
                                $news[$first_file]["ref_id"] = $a_ref_id;
                        }
                }
                
                foreach($to_del as $v)
                {
                        unset($news[$v]);
                }
                
                return $news;
        }

        
        function getAggregatedChildNewsData($a_ref_id, $a_only_public = false,
                $a_time_period = 0, $a_prevent_aggregation = false, $a_starting_date = "")
        {
                global $tree, $ilAccess, $ilBench;
                
                $ilBench->start("News", "getAggregatedChildNewsData");
                
                // get news of parent object
                $data = $this->getNewsForRefId($a_ref_id, $a_only_public, true, $a_time_period);
                foreach ($data as $k => $v)
                {
                        $data[$k]["ref_id"] = $a_ref_id;
                }

                // get childs
                $nodes = $tree->getChilds($a_ref_id);
                
                // no check, for which of the objects any news are available
                $obj_ids = array();
                foreach($nodes as $node)
                {
                        $obj_ids[] = $node["obj_id"];
                }
                $news_obj_ids = ilNewsItem::filterObjIdsPerNews($obj_ids, $a_time_period);
                //$news_obj_ids = $obj_ids;

                // get news for all subtree nodes
                $contexts = array();
                foreach($nodes as $node)
                {
                        // only go on, if news are available
                        if (!in_array($node["obj_id"], $news_obj_ids))
                        {
                                continue;
                        }

                        if (!$a_only_public && !$ilAccess->checkAccess("read", "", $node["child"]))
                        {
                                continue;
                        }
                        $ref_id[$node["obj_id"]] = $node["child"];
                        $contexts[] = array("obj_id" => $node["obj_id"],
                                "obj_type" => $node["type"]);
                }
                
                $news = $this->queryNewsForMultipleContexts($contexts, $a_only_public, $a_time_period,
                        $a_starting_date);
                foreach ($news as $k => $v)
                {
                        $news[$k]["ref_id"] = $ref_id[$v["context_obj_id"]];
                }
                $data = ilNewsItem::mergeNews($data, $news);
                
                // sort and return
                $data = ilUtil::sortArray($data, "creation_date", "desc", false, true);
                
                if (!$a_prevent_aggregation)
                {
                        $data = $this->aggregateFiles($data, $a_ref_id);
                }
                
                $ilBench->stop("News", "getAggregatedChildNewsData");
                
                return $data;
        }

        function setContext($a_obj_id, $a_obj_type, $a_sub_obj_id = 0, $a_sub_obj_type = "")
        {
                $this->setContextObjId($a_obj_id);
                $this->setContextObjType($a_obj_type);
                $this->setContextSubObjId($a_sub_obj_id);
                $this->setContextSubObjType($a_sub_obj_type);
        }

        public function queryNewsForContext($a_for_rss_use = false, $a_time_period = 0,
                $a_starting_date = "")
        {
                global $ilDB, $ilUser;
                
                $and = ($a_time_period > 0)
                        ? " AND (TO_DAYS(now()) - TO_DAYS(creation_date)) <= ".((int)$a_time_period)
                        : "";
                
                if ($a_starting_date != "")
                {
                        $and.= " AND creation_date > ".$ilDB->quote($a_starting_date)." ";
                }

                if ($a_for_rss_use)
                {
                        $query = "SELECT * ".
                                "FROM il_news_item ".
                                " WHERE ".
                                        "context_obj_id = ".$ilDB->quote($this->getContextObjId()).
                                        " AND context_obj_type = ".$ilDB->quote($this->getContextObjType()).
                                        $and.
                                        " ORDER BY creation_date DESC ";
                }
                else
                {
                        $query = "SELECT il_news_item.* ".
                                ", il_news_read.user_id as user_read ".
                                "FROM il_news_item LEFT JOIN il_news_read ".
                                "ON il_news_item.id = il_news_read.news_id AND ".
                                " il_news_read.user_id = ".$ilDB->quote($ilUser->getId()).
                                " WHERE ".
                                        "context_obj_id = ".$ilDB->quote($this->getContextObjId()).
                                        " AND context_obj_type = ".$ilDB->quote($this->getContextObjType()).
                                        $and.
                                        " ORDER BY creation_date DESC ";
                }
                                
                $set = $ilDB->query($query);
                $result = array();
                while($rec = $set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        if (!$a_for_rss_use || ($rec["visibility"] == NEWS_PUBLIC ||
                                ($rec["priority"] == 0 &&
                                ilBlockSetting::_lookup("news", "public_notifications",
                                0, $rec["context_obj_id"]))))
                        {
                                $result[$rec["id"]] = $rec;
                        }
                }

                return $result;

        }
        
        public function queryNewsForMultipleContexts($a_contexts, $a_for_rss_use = false,
                $a_time_period = 0, $a_starting_date = "")
        {
                global $ilDB, $ilUser, $ilBench;
                
                $ilBench->start("News", "queryNewsForMultipleContexts");
                
                $and = ($a_time_period > 0)
                        ? " AND (TO_DAYS(now()) - TO_DAYS(creation_date)) <= ".((int)$a_time_period)
                        : "";
                        
                if ($a_starting_date != "")
                {
                        $and.= " AND creation_date > ".$ilDB->quote($a_starting_date)." ";
                }
                
                $ids = array();
                $type = array();
                foreach($a_contexts as $cont)
                {
                        $ids[] = $cont["obj_id"];
                        $type[$cont["obj_id"]] = $cont["obj_type"];
                }
                
                if ($a_for_rss_use)
                {
                        $query = "SELECT * ".
                                "FROM il_news_item ".
                                " WHERE ".
                                        "context_obj_id IN (".implode(",",ilUtil::quoteArray($ids)).") ".
                                        $and.
                                        " ORDER BY creation_date DESC ";
                }
                else
                {
                        $query = "SELECT il_news_item.* ".
                                ", il_news_read.user_id as user_read ".
                                "FROM il_news_item LEFT JOIN il_news_read ".
                                "ON il_news_item.id = il_news_read.news_id AND ".
                                " il_news_read.user_id = ".$ilDB->quote($ilUser->getId()).
                                " WHERE ".
                                        "context_obj_id IN (".implode(",",ilUtil::quoteArray($ids)).") ".
                                        $and.
                                        " ORDER BY creation_date DESC ";
                }

                $set = $ilDB->query($query);
                $result = array();
                while($rec = $set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        if ($type[$rec["context_obj_id"]] == $rec["context_obj_type"])
                        {
                                if (!$a_for_rss_use || ($rec["visibility"] == NEWS_PUBLIC ||
                                        ($rec["priority"] == 0 &&
                                        ilBlockSetting::_lookup("news", "public_notifications",
                                        0, $rec["context_obj_id"]))))
                                {
                                        $result[$rec["id"]] = $rec;
                                }
                        }
                }

                $ilBench->stop("News", "queryNewsForMultipleContexts");
                
                return $result;

        }


        function _setRead($a_user_id, $a_news_id)
        {
                global $ilDB, $ilAppEventHandler;
                
                $q = "REPLACE INTO il_news_read (user_id, news_id) VALUES (".
                        $ilDB->quote($a_user_id).",".$ilDB->quote($a_news_id).")";
                $ilDB->query($q);

                $ilAppEventHandler->raise("Services/News", "readNews",
                        array("user_id" => $a_user_id, "news_ids" => array($a_news_id)));
        }
        
        function _setUnread($a_user_id, $a_news_id)
        {
                global $ilDB, $ilAppEventHandler;
                
                $q = "DELETE FROM il_news_read (user_id, news_id) VALUES (".
                        " WHERE user_id = ".$ilDB->quote($a_user_id).
                        " AND news_id = ".$ilDB->quote($a_news_id);
                $ilDB->query($q);

                $ilAppEventHandler->raise("Services/News", "unreadNews",
                        array("user_id" => $a_user_id, "news_ids" => array($a_news_id)));
        }
        
        function mergeNews($n1, $n2)
        {
                foreach($n2 as $id => $news)
                {
                        $n1[$id] = $news;
                }
                
                return $n1;
        }
        
        static function _getDefaultVisibilityForRefId($a_ref_id)
        {
                global $tree, $ilSetting;

                include_once("./Services/Block/classes/class.ilBlockSetting.php");

                $news_set = new ilSetting("news");
                $default_visibility = ($news_set->get("default_visibility") != "")
                                ? $news_set->get("default_visibility")
                                : "users";

                if ($tree->isInTree($a_ref_id))
                {
                        $path = $tree->getPathFull($a_ref_id);
                        
                        foreach ($path as $key => $row)
                        {
                                if (!in_array($row["type"], array("root", "cat","crs", "fold", "grp", "icrs")))
                                {
                                        continue;
                                }

                                $visibility = ilBlockSetting::_lookup("news", "default_visibility",
                                        0, $row["obj_id"]);
                                        
                                if ($visibility != "")
                                {
                                        $default_visibility = $visibility;
                                }
                        }
                }
                
                return $default_visibility;
        }
        
        
        public function delete()
        {
                global $ilDB;
                
                // delete il_news_read entries
                $query = "DELETE FROM il_news_read ".
                        " WHERE news_id = ".$ilDB->quote($this->getId());
                $ilDB->query($query);
                
                // delete multimedia object
                $mob = $this->getMobId();
                
                // delete 
                parent::delete();
                
                // delete mob after news, to have a "mob usage" of 0
                if ($mob > 0 and ilObject::_exists($mob))
                {
                        include_once("./Services/MediaObjects/classes/class.ilObjMediaObject.php");
                        $mob = new ilObjMediaObject($mob);
                        $mob->delete();
                }
        }
        
        public function deleteNewsOfContext($a_context_obj_id,
                $a_context_obj_type)
        {
                global $ilDB;
                
                if ($a_context_obj_id == 0 || $a_context_obj_type == "")
                {
                        return;
                }
                
                // get news records
                $query = "SELECT * FROM il_news_item".
                        " WHERE context_obj_id = ".$ilDB->quote($a_context_obj_id).
                        " AND context_obj_type = ".$ilDB->quote($a_context_obj_type);
                        
                $news_set = $ilDB->query($query);
                
                while ($news = $news_set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $news_obj = new ilNewsItem($news["id"]);
                        $news_obj->delete();
                }
        }

        static function _lookupTitle($a_news_id)
        {
                global $ilDB;
                
                $query = "SELECT title FROM il_news_item WHERE id = ".
                        $ilDB->quote($a_news_id);
                $set = $ilDB->query($query);
                $rec = $set->fetchRow(DB_FETCHMODE_ASSOC);
                return $rec["title"];
        }

        static function _lookupVisibility($a_news_id)
        {
                global $ilDB;
                
                $query = "SELECT visibility FROM il_news_item WHERE id = ".
                        $ilDB->quote($a_news_id);
                $set = $ilDB->query($query);
                $rec = $set->fetchRow(DB_FETCHMODE_ASSOC);

                return $rec["visibility"];
        }
        
        static function filterObjIdsPerNews($a_obj_ids, $a_time_period = 0)
        {
                global $ilDB;
                
                $and = ($a_time_period > 0)
                        ? " AND (TO_DAYS(now()) - TO_DAYS(creation_date)) <= ".((int)$a_time_period)
                        : "";
                
                $query = "SELECT DISTINCT(context_obj_id) AS obj_id FROM il_news_item".
                        " WHERE context_obj_id IN (".implode(ilUtil::quoteArray($a_obj_ids),",").")".$and;

                $set = $ilDB->query($query);
                $objs = array();
                while($rec = $set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $objs[] = $rec["obj_id"];
                }
                return $objs;
        }
        
        static function determineNewsTitle($a_context_obj_type, $a_title, $a_content_is_lang_var,
                $a_agg_ref_id = 0, $a_aggregation = "")
        {
                global $lng;

                if ($a_agg_ref_id > 0)
                {
                        $cnt = count($a_aggregation);
                        
                        // forums
                        if ($a_context_obj_type == "frm")
                        {
                                if ($cnt > 1)
                                {
                                        return sprintf($lng->txt("news_x_postings"), $cnt);
                                }
                                else
                                {
                                        return $lng->txt("news_1_postings");
                                }
                        }
                        else    // files
                        {
                                $up_cnt = $cr_cnt = 0;
                                foreach($a_aggregation as $item)
                                {
                                        if ($item["title"] == "file_updated")
                                        {
                                                $up_cnt++;
                                        }
                                        else
                                        {
                                                $cr_cnt++;
                                        }
                                }
                                $sep = "";
                                if ($cr_cnt == 1)
                                {
                                        $tit = $lng->txt("news_1_file_created");
                                        $sep = "<br />";
                                }
                                else if ($cr_cnt > 1)
                                {
                                        $tit = sprintf($lng->txt("news_x_files_created"), $cr_cnt);
                                        $sep = "<br />";
                                }
                                if ($up_cnt == 1)
                                {
                                        $tit .= $sep.$lng->txt("news_1_file_updated");
                                }
                                else if ($up_cnt > 1)
                                {
                                        $tit .= $sep.sprintf($lng->txt("news_x_files_updated"), $up_cnt);
                                }
                                return $tit;
                        }
                }
                else
                {
                        if ($a_content_is_lang_var)
                        {
                                return $lng->txt($a_title);
                        }
                        else
                        {
                                return $a_title;
                        }
                }
                
                return "";
        }
        
        
        static function getFirstNewsIdForContext($a_context_obj_id,
                $a_context_obj_type, $a_context_sub_obj_id = "", $a_context_sub_obj_type = "")
        {
                global $ilDB;
                
                // Determine how many rows should be deleted
                $query = "SELECT * ".
                        "FROM il_news_item ".
                        "WHERE ".
                                "context_obj_id = ".$ilDB->quote($a_context_obj_id).
                                " AND context_obj_type = ".$ilDB->quote($a_context_obj_type).
                                " AND context_sub_obj_id = ".$ilDB->quote($a_context_sub_obj_id).
                                " AND context_sub_obj_type = ".$ilDB->quote($a_context_sub_obj_type);
                                
                $set = $ilDB->query($query);
                $rec = $set->fetchRow(DB_FETCHMODE_ASSOC);
                
                return $rec["id"];
        }
        
        static function _lookupMediaObjectUsages($a_mob_id)
        {
                global $ilDB;
                
                $query = "SELECT * ".
                        "FROM il_news_item ".
                        "WHERE ".
                                " mob_id = ".$ilDB->quote($a_mob_id);
                                
                $usages = array();
                $set = $ilDB->query($query);
                while ($rec = $set->fetchRow(DB_FETCHMODE_ASSOC))
                {
                        $usages[$rec["id"]] = array("type" => "news", "id" => $rec["id"]);
                }
                
                return $usages;
        }

        static function _lookupContextObjId($a_news_id)
        {
                global $ilDB;
                
                $query = "SELECT * ".
                        "FROM il_news_item ".
                        "WHERE ".
                                " id = ".$ilDB->quote($a_news_id);
                $set = $ilDB->query($query);
                $rec = $set->fetchRow(DB_FETCHMODE_ASSOC);
                
                return $rec["context_obj_id"];
        }

        function _lookupDefaultPDPeriod()
        {
                $news_set = new ilSetting("news");
                $per = $news_set->get("pd_period");
                if ($per == 0)
                {
                        $per = 30;
                }
                
                return $per;
        }
        
        function _lookupUserPDPeriod($a_user_id)
        {
                global $ilSetting;
                
                $news_set = new ilSetting("news");
                $allow_shorter_periods = $news_set->get("allow_shorter_periods");
                $allow_longer_periods = $news_set->get("allow_longer_periods");
                $default_per = ilNewsItem::_lookupDefaultPDPeriod();
                
                include_once("./Services/Block/classes/class.ilBlockSetting.php");
                $per = ilBlockSetting::_lookup("pdnews", "news_pd_period",
                        $a_user_id, 0);

                // news period information
                if ($per <= 0 ||
                        (!$allow_shorter_periods && ($per < $default_per)) ||
                        (!$allow_longer_periods && ($per > $default_per))
                        )
                {
                        $per = $default_per;
                }
                
                return $per;
        }
        
        function _lookupRSSPeriod()
        {
                $news_set = new ilSetting("news");
                $rss_period = $news_set->get("rss_period");
                if ($rss_period == 0)           // default to two weeks
                {
                        $rss_period = 14;
                }
                return $rss_period;
        }
}
?>