<?php
/*
 * Nucleus: PHP/MySQL Weblog CMS (http://nucleuscms.org/)
 * Copyright (C) 2002-2013 The Nucleus Group
 *
 * 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.
 * (see nucleus/documentation/index.html#license for more info)
 *
 * This class makes sure each item/weblog/comment object gets requested from
 * the database only once, by keeping them in a cache. The class also acts as
 * a dynamic classloader, loading classes _only_ when they are first needed,
 * hoping to diminish execution time
 *
 * The class is a singleton, meaning that there will be only one object of it
 * active at all times. The object can be requested using MANAGER::instance()
 */
class MANAGER {

    /**
     * Cached ITEM, BLOG, PLUGIN, KARMA and MEMBER objects. When these objects are requested
     * through the global $manager object (getItem, getBlog, ...), only the first call
     * will create an object. Subsequent calls will return the same object.
     *
     * The $items, $blogs, ... arrays map an id to an object (for plugins, the name is used
     * rather than an ID)
     */
    var $items;
    var $blogs;
    var $plugins;
    var $karma;
    var $templates;
    var $members;

    /**
     * cachedInfo to avoid repeated SQL queries (see pidInstalled/pluginInstalled/getPidFromName)
     * e.g. which plugins exists?
     *
     * $cachedInfo['installedPlugins'] = array($pid -> $name)
     */
    var $cachedInfo;

    /**
      * The plugin subscriptionlist
      *
      * The subcription array has the following structure
      *     $subscriptions[$EventName] = array containing names of plugin classes to be
      *                                  notified when that event happens
      */
    var $subscriptions;

    /**
      * Returns the only instance of this class. Creates the instance if it
      * does not yet exists. Users should use this function as
      * $manager =& MANAGER::instance(); to get a reference to the object
      * instead of a copy
      */
    function &instance() {
        static $instance = array();
        if (empty($instance)) {
            $instance[0] = new MANAGER();
        }
        return $instance[0];
    }

    /**
      * The constructor of this class initializes the object caches
      */
    function MANAGER() {
        $this->items = array();
        $this->blogs = array();
        $this->plugins = array();
        $this->karma = array();
        $this->parserPrefs = array();
        $this->cachedInfo = array();
    }

    /**
      * Returns the requested item object. If it is not in the cache, it will
      * first be loaded and then placed in the cache.
      * Intended use: $item =& $manager->getItem(1234)
      */
    function &getItem($itemid, $allowdraft, $allowfuture) {
        $item =& $this->items[$itemid];

        // check the draft and future rules if the item was already cached
        if ($item) {
            if ((!$allowdraft) && ($item['draft']))
                return 0;

            $blog =& $this->getBlog(getBlogIDFromItemID($itemid));
            if ((!$allowfuture) && ($item['timestamp'] > $blog->getCorrectTime()))
                return 0;
        }
        if (!$item) {
            // load class if needed
            $this->loadClass('ITEM');
            // load item object
            $item = ITEM::getitem($itemid, $allowdraft, $allowfuture);
            $this->items[$itemid] = $item;
        }
        return $item;
    }

    /**
      * Loads a class if it has not yet been loaded
      */
    function loadClass($name) {
        $this->_loadClass($name, $name . '.php');
    }

    /**
      * Checks if an item exists
      */
    function existsItem($id,$future,$draft) {
        $this->_loadClass('ITEM','ITEM.php');
        return ITEM::exists($id,$future,$draft);
    }

    /**
      * Checks if a category exists
      */
    function existsCategory($id) {
        return (quickQuery('SELECT COUNT(*) as result FROM '.sql_table('category').' WHERE catid='.intval($id)) > 0);
    }

    /**
      * Returns the blog object for a given blogid
      */
    function &getBlog($blogid) {
        $blog =& $this->blogs[$blogid];

        if (!$blog) {
            // load class if needed
            $this->_loadClass('BLOG','BLOG.php');
            // load blog object
            $blog = new BLOG($blogid);
            $this->blogs[$blogid] =& $blog;
        }
        return $blog;
    }

    /**
      * Checks if a blog exists
      */
    function existsBlog($name) {
        $this->_loadClass('BLOG','BLOG.php');
        return BLOG::exists($name);
    }

    /**
      * Checks if a blog id exists
      */
    function existsBlogID($id) {
        $this->_loadClass('BLOG','BLOG.php');
        return BLOG::existsID($id);
    }

    /**
     * Returns a previously read template
     */
    function &getTemplate($templateName) {
        $template =& $this->templates[$templateName];

        if (!$template) {
            $template = TEMPLATE::read($templateName);
            $this->templates[$templateName] =& $template;
        }
        return $template;
    }

    /**
     * Returns a KARMA object (karma votes)
     */
    function &getKarma($itemid) {
        $karma =& $this->karma[$itemid];

        if (!$karma) {
            // load class if needed
            $this->_loadClass('KARMA','KARMA.php');
            // create KARMA object
            $karma = new KARMA($itemid);
            $this->karma[$itemid] =& $karma;
        }
        return $karma;
    }

    /**
     * Returns a MEMBER object
     */
    function &getMember($memberid) {
        $mem =& $this->members[$memberid];

        if (!$mem) {
            // load class if needed
            $this->_loadClass('MEMBER','MEMBER.php');
            // create MEMBER object
            $mem =& MEMBER::createFromID($memberid);
            $this->members[$memberid] =& $mem;
        }
        return $mem;
    }

    /**
     * Set the global parser preferences
     */
    function setParserProperty($name, $value) {
        $this->parserPrefs[$name] = $value;
    }

    /**
     * Get the global parser preferences
     */
    function getParserProperty($name) {
        return $this->parserPrefs[$name];
    }

    /**
      * A helper function to load a class
      * 
      * private
      */
    function _loadClass($name, $filename) {
        if (!class_exists($name)) {
                global $DIR_LIBS;
                include($DIR_LIBS . $filename);
        }
    }

    /**
      * A helper function to load a plugin
      * 
      * private
      */
    function _loadPlugin($name) {
        if (!class_exists($name)) {
                global $DIR_PLUGINS;

                $fileName = $DIR_PLUGINS . $name . '.php';

                if (!file_exists($fileName))
                {
                    if (!defined('_MANAGER_PLUGINFILE_NOTFOUND')) {
                        define('_MANAGER_PLUGINFILE_NOTFOUND', 'Plugin %s was not loaded (File not found)');
                    }
                    ACTIONLOG::add(WARNING, sprintf(_MANAGER_PLUGINFILE_NOTFOUND, $name));
                    return 0;
                }

                // load plugin
                include($fileName);

                // check if class exists (avoid errors in eval'd code)
                if (!class_exists($name))
                {
                    if (!defined('_MANAGER_PLUGINFILE_NOCLASS')) {
                        define('_MANAGER_PLUGINFILE_NOCLASS', "Plugin %s was not loaded (Class not found in file, possible parse error)");
                    }
                    ACTIONLOG::add(WARNING, sprintf(_MANAGER_PLUGINFILE_NOCLASS, $name));
                    return 0;
                }

                // add to plugin array
                eval('$this->plugins[$name] = new ' . $name . '();');

                // get plugid
                $this->plugins[$name]->plugid = $this->getPidFromName($name);

                // unload plugin if a prefix is used and the plugin cannot handle this^
                global $MYSQL_PREFIX;
                if (($MYSQL_PREFIX != '') && !$this->plugins[$name]->supportsFeature('SqlTablePrefix'))
                {
                    unset($this->plugins[$name]);
                    ACTIONLOG::add(WARNING, sprintf(_MANAGER_PLUGINTABLEPREFIX_NOTSUPPORT, $name));
                    return 0;
                }

                // unload plugin if using non-mysql handler and plugin does not support it 
                global $MYSQL_HANDLER;
                if ((!in_array('mysql',$MYSQL_HANDLER)) && !$this->plugins[$name]->supportsFeature('SqlApi'))
                {
                    unset($this->plugins[$name]);
                    ACTIONLOG::add(WARNING, sprintf(_MANAGER_PLUGINSQLAPI_NOTSUPPORT, $name));
                    return 0;
                }

                // call init method
                $this->plugins[$name]->init();

        }
    }

    /**
     * Returns a PLUGIN object
     */
    function &getPlugin($name) {
        // retrieve the name of the plugin in the right capitalisation
        $name = $this->getUpperCaseName ($name);
        // get the plugin   
        $plugin =& $this->plugins[$name];

        if (!$plugin) {
            // load class if needed
            $this->_loadPlugin($name);
            $plugin =& $this->plugins[$name];
        }
        return $plugin;
    }

    /**
      * Checks if the given plugin IS loaded or not
      */
    function &pluginLoaded($name) {
        $plugin =& $this->plugins[$name];
        return $plugin;
    }

    function &pidLoaded($pid) {
        $plugin=false;
        reset($this->plugins);
        while (list($name) = each($this->plugins)) {
            if ($pid!=$this->plugins[$name]->getId()) continue;
            $plugin= & $this->plugins[$name];
            break;
        }
        return $plugin;
    }

    /**
      * checks if the given plugin IS installed or not
      */
    function pluginInstalled($name) {
        $this->_initCacheInfo('installedPlugins');
        return ($this->getPidFromName($name) != -1);
    }

    function pidInstalled($pid) {
        $this->_initCacheInfo('installedPlugins');
        return ($this->cachedInfo['installedPlugins'][$pid] != '');
    }

    function getPidFromName($name) {
        $this->_initCacheInfo('installedPlugins');
        foreach ($this->cachedInfo['installedPlugins'] as $pid => $pfile)
        {
            if (strtolower($pfile) == strtolower($name))
                return $pid;
        }
        return -1;
    }

    /**
      * Retrieve the name of a plugin in the right capitalisation
      */
    function getUpperCaseName ($name) {
        $this->_initCacheInfo('installedPlugins');
        foreach ($this->cachedInfo['installedPlugins'] as $pid => $pfile)
        {
            if (strtolower($pfile) == strtolower($name))
                return $pfile;
        }
        return -1;
    }

    function clearCachedInfo($what) {
        unset($this->cachedInfo[$what]);
    }

    /**
     * Loads some info on the first call only
     */
    function _initCacheInfo($what)
    {
        if (isset($this->cachedInfo[$what]) && is_array($this->cachedInfo[$what]))
            return;
        switch ($what)
        {
            // 'installedPlugins' = array ($pid => $name)
            case 'installedPlugins':
                $this->cachedInfo['installedPlugins'] = array();
                $res = sql_query('SELECT pid, pfile FROM ' . sql_table('plugin'));
                while ($o = sql_fetch_object($res))
                {
                    $this->cachedInfo['installedPlugins'][$o->pid] = $o->pfile;
                }
                break;
        }
    }

    /**
      * A function to notify plugins that something has happened. Only the plugins
      * that are subscribed to the event will get notified.
      * Upon the first call, the list of subscriptions will be fetched from the
      * database. The plugins itsself will only get loaded when they are first needed
      *
      * @param $eventName
      *     Name of the event (method to be called on plugins)
      * @param $data
      *     Can contain any type of data, depending on the event type. Usually this is
      *     an itemid, blogid, ... but it can also be an array containing multiple values
      */
    function notify($eventName, &$data) {
        // load subscription list if needed
        if (!is_array($this->subscriptions))
            $this->_loadSubscriptions();


        // get listening objects
        $listeners = false;
        if (isset($this->subscriptions[$eventName])) {
            $listeners = $this->subscriptions[$eventName];
        }

        // notify all of them
        if (is_array($listeners)) {
            foreach($listeners as $listener) {
                // load class if needed
                $this->_loadPlugin($listener);
                // do notify (if method exists)
                if (isset($this->plugins[$listener]) && method_exists($this->plugins[$listener], 'event_' . $eventName))
                    call_user_func(array($this->plugins[$listener], 'event_' . $eventName), $data);
            }
        }

    }

    /**
      * Loads plugin subscriptions
      */
    function _loadSubscriptions() {
        // initialize as array
        $this->subscriptions = array();

        $res = sql_query('SELECT p.pfile as pfile, e.event as event FROM '.sql_table('plugin_event').' as e, '.sql_table('plugin').' as p WHERE e.pid=p.pid ORDER BY p.porder ASC');
        while ($o = sql_fetch_object($res)) {
            $pluginName = $o->pfile;
            $eventName = $o->event;
            $this->subscriptions[$eventName][] = $pluginName;
        }

    }

    /*
        Ticket functions. These are uses by the admin area to make it impossible to simulate certain GET/POST
        requests. tickets are user specific
    */

    var $currentRequestTicket = '';

    /**
     * GET requests: Adds ticket to URL (URL should NOT be html-encoded!, ticket is added at the end)
     */
    function addTicketToUrl($url)
    {
        $ticketCode = 'ticket=' . $this->_generateTicket();
        if (strstr($url, '?'))
            return $url . '&' . $ticketCode;
        else
            return $url . '?' . $ticketCode;
    }

    /**
     * POST requests: Adds ticket as hidden formvar
     */
    function addTicketHidden()
    {
        $ticket = $this->_generateTicket();

        echo '<input type="hidden" name="ticket" value="', htmlspecialchars($ticket), '" />';
    }

    /**
     * Get a new ticket
     * (xmlHTTPRequest AutoSaveDraft uses this to refresh the ticket)
     */
    function getNewTicket()
    {
        $this->currentRequestTicket = '';
        return $this->_generateTicket();
    }

    /**
     * Checks the ticket that was passed along with the current request
     */
    function checkTicket()
    {
        global $member;

        // get ticket from request
        $ticket = requestVar('ticket');

        // no ticket -> don't allow
        if ($ticket == '')
            return false;

        // remove expired tickets first
        $this->_cleanUpExpiredTickets();

        // get member id
        if (!$member->isLoggedIn())
            $memberId = -1;
        else
            $memberId = $member->getID();

        // check if ticket is a valid one
        $query = 'SELECT COUNT(*) as result FROM ' . sql_table('tickets') . ' WHERE member=' . intval($memberId). ' and ticket=\''.sql_real_escape_string($ticket).'\'';
        if (quickQuery($query) == 1)
        {
            // [in the original implementation, the checked ticket was deleted. This would lead to invalid
            //  tickets when using the browsers back button and clicking another link/form
            //  leaving the keys in the database is not a real problem, since they're member-specific and
            //  only valid for a period of one hour
            // ]
            // sql_query('DELETE FROM '.sql_table('tickets').' WHERE member=' . intval($memberId). ' and ticket=\''.addslashes($ticket).'\'');
            return true;
        } else {
            // not a valid ticket
            return false;
        }

    }

    /**
     * (internal method) Removes the expired tickets
     */
    function _cleanUpExpiredTickets()
    {
        // remove tickets older than 1 hour
        $oldTime = time() - 60 * 60;
        $query = 'DELETE FROM ' . sql_table('tickets'). ' WHERE ctime < \'' . date('Y-m-d H:i:s',$oldTime) .'\'';
        sql_query($query);
    }

    /**
     * (internal method) Generates/returns a ticket (one ticket per page request)
     */
    function _generateTicket()
    {
        if ($this->currentRequestTicket == '')
        {
            // generate new ticket (only one ticket will be generated per page request)
            // and store in database
            global $member;
            // get member id
            if (!$member->isLoggedIn())
                $memberId = -1;
            else
                $memberId = $member->getID();

            $ok = false;
            while (!$ok)
            {
                // generate a random token
                srand((double)microtime()*1000000);
                $ticket = md5(uniqid(rand(), true));

                // add in database as non-active
                $query = 'INSERT INTO ' . sql_table('tickets') . ' (ticket, member, ctime) ';
                $query .= 'VALUES (\'' . sql_real_escape_string($ticket). '\', \'' . intval($memberId). '\', \'' . date('Y-m-d H:i:s',time()) . '\')';
                if (sql_query($query))
                    $ok = true;
            }

            $this->currentRequestTicket = $ticket;
        }
        return $this->currentRequestTicket;
    }

}

?>