<?php
// $Id: notification.php,v 1.3 2006/05/01 02:37:28 onokazu Exp $
//  ------------------------------------------------------------------------ //
//                XOOPS - PHP Content Management System                      //
//                    Copyright (c) 2000 XOOPS.org                           //
//                       <http://www.xoops.org/>                             //
//  ------------------------------------------------------------------------ //
//  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.                                      //
//                                                                           //
//  You may not change or alter any portion of this comment or credits       //
//  of supporting developers from this source code or any supporting         //
//  source code which is considered copyrighted (c) material of the          //
//  original comment or credit authors.                                      //
//                                                                           //
//  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 //
//  ------------------------------------------------------------------------ //
// Author: Kazumi Ono (AKA onokazu)                                          //
// URL: http://www.xoops.org/ http://jp.xoops.org/  http://www.myweb.ne.jp/  //
// Project: The XOOPS Project (http://www.xoops.org/)                        //
// ------------------------------------------------------------------------- //

if (!defined('XOOPS_ROOT_PATH')) {
    exit();
}
// RMV-NOTIFY
include_once XOOPS_ROOT_PATH . '/include/notification_constants.php';
include_once XOOPS_ROOT_PATH . '/include/notification_functions.php';

/**
 *
 *
 * @package     kernel
 * @subpackage  notification
 *
 * @author      Michael van Dam <mvandam@caltech.edu>
 * @copyright   copyright (c) 2000-2003 XOOPS.org
 */

/**
 * A Notification
 *
 * @package     kernel
 * @subpackage  notification
 *
 * @author      Michael van Dam <mvandam@caltech.edu>
 * @copyright   copyright (c) 2000-2003 XOOPS.org
 */
class XoopsNotification extends XoopsObject
{
    /**
     * Constructor
     **/
    function XoopsNotification()
    {
        $this->XoopsObject();
        $this->initVar('not_id', XOBJ_DTYPE_INT, NULL, false);
        $this->initVar('not_modid', XOBJ_DTYPE_INT, NULL, false);
        $this->initVar('not_category', XOBJ_DTYPE_TXTBOX, null, false, 30);
        $this->initVar('not_itemid', XOBJ_DTYPE_INT, 0, false);
        $this->initVar('not_event', XOBJ_DTYPE_TXTBOX, null, false, 30);
        $this->initVar('not_uid', XOBJ_DTYPE_INT, 0, true);
        $this->initVar('not_mode', XOBJ_DTYPE_INT, 0, false);
    }

// FIXME:???
// To send email to multiple users simultaneously, we would need to move
// the notify functionality to the handler class.  BUT, some of the tags
// are user-dependent, so every email msg will be unique.  (Unless maybe use
// smarty for email templates in the future.)  Also we would have to keep
// track if each user wanted email or PM.

    /**
     * Send a notification message to the user
     *
     * @param  string  $template_dir  Template directory
     * @param  string  $template      Template name
     * @param  string  $subject       Subject line for notification message
     * @param  array   $tags Array of substitutions for template variables
     *
     * @return  bool    true if success, false if error
     **/
    function notifyUser($template_dir, $template, $subject, $tags)
    {
        // Check the user's notification preference.
        $member_handler =& xoops_gethandler('member');
        $user =& $member_handler->getUser($this->getVar('not_uid'));
        if (!is_object($user)) {
            return true;
        }
        $method = $user->getVar('notify_method');
        $xoopsMailer =& getMailer();
        include_once XOOPS_ROOT_PATH . '/include/notification_constants.php';
        switch($method) {
        case XOOPS_NOTIFICATION_METHOD_PM:
            $xoopsMailer->usePM();
            $config_handler =& xoops_gethandler('config');
            $xoopsMailerConfig =& $config_handler->getConfigsByCat(XOOPS_CONF_MAILER);
            $xoopsMailer->setFromUser($member_handler->getUser($xoopsMailerConfig['fromuid']));
            foreach ($tags as $k=>$v) {
                $xoopsMailer->assign($k, $v);
            }
            break;
        case XOOPS_NOTIFICATION_METHOD_EMAIL:
            $xoopsMailer->useMail();
            foreach ($tags as $k=>$v) {
                $xoopsMailer->assign($k, preg_replace("/&amp;/i", '&', $v));
            }
            break;
        default:
            return true; // report error in user's profile??
            break;
        }
        // Set up the mailer
        $xoopsMailer->setTemplateDir($template_dir);
        $xoopsMailer->setTemplate($template);
        $xoopsMailer->setToUsers($user);
        //global $xoopsConfig;
        //$xoopsMailer->setFromEmail($xoopsConfig['adminmail']);
        //$xoopsMailer->setFromName($xoopsConfig['sitename']);
        $xoopsMailer->setSubject($subject);
        $success = $xoopsMailer->send();
        // If send-once-then-delete, delete notification
        // If send-once-then-wait, disable notification
        include_once XOOPS_ROOT_PATH . '/include/notification_constants.php';
        $notification_handler =& xoops_gethandler('notification');
        if ($this->getVar('not_mode') == XOOPS_NOTIFICATION_MODE_SENDONCETHENDELETE) {
            $notification_handler->delete($this);
            return $success;
        }
        if ($this->getVar('not_mode') == XOOPS_NOTIFICATION_MODE_SENDONCETHENWAIT) {
            $this->setVar('not_mode', XOOPS_NOTIFICATION_MODE_WAITFORLOGIN);
            $notification_handler->insert($this);
        }
        return $success;
    }
}

/**
 * XOOPS notification handler class.
 *
 * This class is responsible for providing data access mechanisms to the data source
 * of XOOPS notification class objects.
 *
 *
 * @package     kernel
 * @subpackage  notification
 *
 * @author      Michael van Dam <mvandam@caltech.edu>
 * @copyright   copyright (c) 2000-2003 XOOPS.org
 */
class XoopsNotificationHandler extends XoopsObjectHandler
{

    /**
     * Create a {@link XoopsNotification}
     *
     * @param   bool    $isNew  Flag the object as "new"?
     *
     * @return  object
     */
    function &create($isNew = true)
    {
        $notification =& new XoopsNotification();
        if ($isNew) {
            $notification->setNew();
        }
        return $notification;
    }

    /**
     * Retrieve a {@link XoopsNotification}
     *
     * @param   int $id ID
     *
     * @return  object  {@link XoopsNotification}, FALSE on fail
     **/
    function &get($id)
    {
        $id = intval($id);
        $ret = false;
        if ($id > 0) {
            $sql = 'SELECT * FROM '.$this->db->prefix('xoopsnotifications').' WHERE not_id='.$id;
            if ($result = $this->db->query($sql)) {
                $numrows = $this->db->getRowsNum($result);
                if ($numrows == 1) {
                    $notification =& new XoopsNotification();
                    $notification->assignVars($this->db->fetchArray($result));
                    $ret =& $notification;
                }
            }
        }
        return $ret;
    }

    /**
     * Write a notification(subscription) to database
     *
     * @param   object  &$notification
     *
     * @return  bool
     **/
    function insert(&$notification)
    {
        if (strtolower(get_class($notification)) != 'xoopsnotification') {
            return false;
        }
        if (!$notification->isDirty()) {
            return true;
        }
        if (!$notification->cleanVars()) {
            return false;
        }
        foreach ($notification->cleanVars as $k => $v) {
            ${$k} = $v;
        }
        if ($notification->isNew()) {
            $not_id = $this->db->genId('xoopsnotifications_not_id_seq');
        $sql = sprintf("INSERT INTO %s (not_id, not_modid, not_itemid, not_category, not_uid, not_event, not_mode) VALUES (%u, %u, %u, %s, %u, %s, %u)", $this->db->prefix('xoopsnotifications'), $not_id, $not_modid, $not_itemid, $this->db->quoteString($not_category), $not_uid, $this->db->quoteString($not_event), $not_mode);
        } else {
        $sql = sprintf("UPDATE %s SET not_modid = %u, not_itemid = %u, not_category = %s, not_uid = %u, not_event = %s, not_mode = %u WHERE not_id = %u", $this->db->prefix('xoopsnotifications'), $not_modid, $not_itemid, $this->db->quoteString($not_category), $not_uid, $this->db->quoteString($not_event), $not_mode, $not_id);
        }
        if (!$result = $this->db->query($sql)) {
            return false;
        }
        if (empty($not_id)) {
            $not_id = $this->db->getInsertId();
        }
        $notification->assignVar('not_id', $not_id);
        return true;
    }

    /**
     * Delete a {@link XoopsNotification} from the database
     *
     * @param   object  &$notification
     *
     * @return  bool
     **/
    function delete(&$notification)
    {
        if (strtolower(get_class($notification)) != 'xoopsnotification') {
            return false;
        }
        $sql = sprintf("DELETE FROM %s WHERE not_id = %u", $this->db->prefix('xoopsnotifications'), $notification->getVar('not_id'));
        if (!$result = $this->db->query($sql)) {
            return false;
        }
        return true;
    }

    /**
     * Get some {@link XoopsNotification}s
     *
     * @param   object  $criteria
     * @param   bool    $id_as_key  Use IDs as keys into the array?
     *
     * @return  array   Array of {@link XoopsNotification} objects
     **/
    function &getObjects($criteria = null, $id_as_key = false)
    {
        $ret = array();
        $limit = $start = 0;
        $sql = 'SELECT * FROM '.$this->db->prefix('xoopsnotifications');
        if (isset($criteria) && is_subclass_of($criteria, 'criteriaelement')) {
            $sql .= ' '.$criteria->renderWhere();
            $sort = ($criteria->getSort() != '') ? $criteria->getSort() : 'not_id';
            $sql .= ' ORDER BY '.$sort.' '.$criteria->getOrder();
            $limit = $criteria->getLimit();
            $start = $criteria->getStart();
        }
        $result = $this->db->query($sql, $limit, $start);
        if (!$result) {
            return $ret;
        }
        while ($myrow = $this->db->fetchArray($result)) {
            $notification =& new XoopsNotification();
            $notification->assignVars($myrow);
            if (!$id_as_key) {
                $ret[] =& $notification;
            } else {
                $ret[$myrow['not_id']] =& $notification;
            }
            unset($notification);
        }
        return $ret;
    }

// TODO: Need this??
    /**
     * Count Notifications
     *
     * @param   object  $criteria   {@link CriteriaElement}
     *
     * @return  int     Count
     **/
    function getCount($criteria = null)
    {
        $sql = 'SELECT COUNT(*) FROM '.$this->db->prefix('xoopsnotifications');
        if (isset($criteria) && is_subclass_of($criteria, 'criteriaelement')) {
            $sql .= ' '.$criteria->renderWhere();
        }
        if (!$result =& $this->db->query($sql)) {
            return 0;
        }
        list($count) = $this->db->fetchRow($result);
        return $count;
    }

    /**
     * Delete multiple notifications
     *
     * @param   object  $criteria   {@link CriteriaElement}
     *
     * @return  bool
     **/
    function deleteAll($criteria = null)
    {
        $sql = 'DELETE FROM '.$this->db->prefix('xoopsnotifications');
        if (isset($criteria) && is_subclass_of($criteria, 'criteriaelement')) {
            $sql .= ' '.$criteria->renderWhere();
        }
        if (!$result = $this->db->query($sql)) {
            return false;
        }
        return true;
    }

// Need this??
    /**
     * Change a value in multiple notifications
     *
     * @param   string  $fieldname  Name of the field
     * @param   string  $fieldvalue Value to write
     * @param   object  $criteria   {@link CriteriaElement}
     *
     * @return  bool
     **/
/*
    function updateAll($fieldname, $fieldvalue, $criteria = null)
    {
        $set_clause = is_numeric($fieldvalue) ? $filedname.' = '.$fieldvalue : $filedname." = '".$fieldvalue."'";
        $sql = 'UPDATE '.$this->db->prefix('xoopsnotifications').' SET '.$set_clause;
        if (isset($criteria) && is_subclass_of($criteria, 'criteriaelement')) {
            $sql .= ' '.$criteria->renderWhere();
        }
        if (!$result = $this->db->query($sql)) {
            return false;
        }
        return true;
    }
*/

    // TODO: rename this...
    // Also, should we have get by module, get by category, etc...??

    function &getNotification ($module_id, $category, $item_id, $event, $user_id)
    {
        $ret = false;
        $criteria = new CriteriaCompo();
        $criteria->add(new Criteria('not_modid', intval($module_id)));
        $criteria->add(new Criteria('not_category', $category));
        $criteria->add(new Criteria('not_itemid', intval($item_id)));
        $criteria->add(new Criteria('not_event', $event));
        $criteria->add(new Criteria('not_uid', intval($user_id)));
        $objects = $this->getObjects($criteria);
        if (count($objects) == 1) {
            $ret =& $objects[0];
        }
        return $ret;
    }

    /**
     * Determine if a user is subscribed to a particular event in
     * a particular module.
     *
     * @param  string  $category  Category of notification event
     * @param  int     $item_id   Item ID of notification event
     * @param  string  $event     Event
     * @param  int     $module_id ID of module (default current module)
     * @param  int     $user_id   ID of user (default current user)
     * return int  0 if not subscribe; non-zero if subscribed
     */

    function isSubscribed ($category, $item_id, $event, $module_id, $user_id)
    {
        $criteria = new CriteriaCompo();
        $criteria->add(new Criteria('not_modid', intval($module_id)));
        $criteria->add(new Criteria('not_category', $category));
        $criteria->add(new Criteria('not_itemid', intval($item_id)));
        $criteria->add(new Criteria('not_event', $event));
        $criteria->add(new Criteria('not_uid', intval($user_id)));
        return $this->getCount($criteria);
    }

    // TODO: how about a function to subscribe a whole group of users???
    // e.g. if we want to add all moderators to be notified of subscription
    // of new threads...

    /**
     * Subscribe for notification for an event(s)
     *
     * @param  string $category    category of notification
     * @param  int    $item_id     ID of the item
     * @param  mixed  $events      event string or array of events
     * @param  int    $mode        force a particular notification mode
     *                             (e.g. once_only) (default to current user preference)
     * @param  int    $module_id   ID of the module (default to current module)
     * @param  int    $user_id     ID of the user (default to current user)
     **/
    function subscribe ($category, $item_id, $events, $mode=null, $module_id=null, $user_id=null)
    {
        if (!isset($user_id)) {
            global $xoopsUser;
            if (empty($xoopsUser)) {
                return false;  // anonymous cannot subscribe
            } else {
                $user_id = $xoopsUser->getVar('uid');
            }
        }
        if (!isset($module_id)) {
            global $xoopsModule;
            $module_id = $xoopsModule->getVar('mid');
        }
        if (!isset($mode)) {
            $user = new XoopsUser($user_id);
            $mode = $user->getVar('notify_mode');
        }
        if (!is_array($events)) $events = array($events);
        foreach ($events as $event) {
            if ($notification =& $this->getNotification($module_id, $category, $item_id, $event, $user_id)) {
                if ($notification->getVar('not_mode') != $mode) {
                    $this->updateByField($notification, 'not_mode', $mode);
                }
            } else {
                $notification =& $this->create();
                $notification->setVar('not_modid', $module_id);
                $notification->setVar('not_category', $category);
                $notification->setVar('not_itemid', $item_id);
                $notification->setVar('not_uid', $user_id);
                $notification->setVar('not_event', $event);
                $notification->setVar('not_mode', $mode);
                $this->insert($notification);
            }
        }
    }

// TODO: this will be to provide a list of everything a particular
// user has subscribed to... e.g. for on the 'Profile' page, similar
// to how we see the various posts etc. that the user has made.
// We may also want to have a function where we can specify module id
    /**
     * Get a list of notifications by user ID
     *
     * @param  int  $user_id  ID of the user
     *
     * @return array  Array of {@link XoopsNotification} objects
     **/
    function &getByUser ($user_id)
    {
        $criteria = new Criteria ('not_uid', $user_id);
        $ret =& $this->getObjects($criteria, true);
        return $ret;
    }

    // TODO: rename this??
    /**
     * Get a list of notification events for the current item/mod/user
     *
     **/
    function &getSubscribedEvents ($category, $item_id, $module_id, $user_id)
    {
        $criteria = new CriteriaCompo();
        $criteria->add (new Criteria('not_modid', $module_id));
        $criteria->add (new Criteria('not_category', $category));
        if ($item_id) {
            $criteria->add (new Criteria('not_itemid', $item_id));
        }
        $criteria->add (new Criteria('not_uid', $user_id));
        $results = $this->getObjects($criteria, true);
        $ret = array();
        foreach (array_keys($results) as $i) {
            $ret[] = $results[$i]->getVar('not_event');
        }
        return $ret;
    }

// TODO: is this a useful function?? (Copied from comment_handler)
    /**
     * Retrieve items by their ID
     *
     * @param   int     $module_id  Module ID
     * @param   int     $item_id    Item ID
     * @param   string  $order      Sort order
     *
     * @return  array   Array of {@link XoopsNotification} objects
     **/
    function &getByItemId($module_id, $item_id, $order = null, $status = null)
    {
        $criteria = new CriteriaCompo(new Criteria('com_modid', intval($module_id)));
        $criteria->add(new Criteria('com_itemid', intval($item_id)));
        if (isset($status)) {
            $criteria->add(new Criteria('com_status', intval($status)));
        }
        if (isset($order)) {
            $criteria->setOrder($order);
        }
        $ret =& $this->getObjects($criteria);
        return $ret;
    }

    /**
     * Send notifications to users
     *
     * @param  string $category   notification category
     * @param  int $item_id    ID of the item
     * @param  string  $event  notification event
     * @param  array  $extra_tags array of substitutions for template to be
     *                             merged with the one from function..
     * @param  array  $user_list  only notify the selected users
     * @param  int $module_id  ID of the module
     * @param  int $omit_user_id    ID of the user to omit from notifications. (default to current user).  set to 0 for all users to receive notification.
     **/
    // TODO:(?) - pass in an event LIST.  This will help to avoid
    // problem of sending people multiple emails for similar events.
    // BUT, then we need an array of mail templates, etc...  Unless
    // mail templates can include logic in the future, then we can
    // tailor the mail so it makes sense for any of the possible
    // (or combination of) events.

    function triggerEvents ($category, $item_id, $events, $extra_tags=array(), $user_list=array(), $module_id=null, $omit_user_id=null)
    {
        if (!is_array($events)) {
            $events = array($events);
        }
        foreach ($events as $event) {
            $this->triggerEvent($category, $item_id, $event, $extra_tags, $user_list, $module_id, $omit_user_id);
        }
    }

    function triggerEvent ($category, $item_id, $event, $extra_tags=array(), $user_list=array(), $module_id=null, $omit_user_id=null)
    {
        if (!isset($module_id)) {
            global $xoopsModule;
            $module =& $xoopsModule;
            $module_id = !empty($xoopsModule) ? $xoopsModule->getVar('mid') : 0;
        } else {
            $module_handler =& xoops_gethandler('module');
            $module =& $module_handler->get($module_id);
        }

        // Check if event is enabled
        $config_handler =& xoops_gethandler('config');
        $mod_config =& $config_handler->getConfigsByCat(0,$module->getVar('mid'));
        if (empty($mod_config['notification_enabled'])) {
            return false;
        }
        $category_info =& notificationCategoryInfo ($category, $module_id);
        $event_info =& notificationEventInfo ($category, $event, $module_id);
        if (!in_array(notificationGenerateConfig($category_info,$event_info,'option_name'),$mod_config['notification_events']) && empty($event_info['invisible'])) {
            return false;
        }

        if (!isset($omit_user_id)) {
            global $xoopsUser;
            if (!empty($xoopsUser)) {
                $omit_user_id = $xoopsUser->getVar('uid');
            } else {
                $omit_user_id = 0;
            }
        }
        $criteria = new CriteriaCompo();
        $criteria->add(new Criteria('not_modid', intval($module_id)));
        $criteria->add(new Criteria('not_category', $category));
        $criteria->add(new Criteria('not_itemid', intval($item_id)));
        $criteria->add(new Criteria('not_event', $event));
        $mode_criteria = new CriteriaCompo();
        $mode_criteria->add (new Criteria('not_mode', XOOPS_NOTIFICATION_MODE_SENDALWAYS), 'OR');
        $mode_criteria->add (new Criteria('not_mode', XOOPS_NOTIFICATION_MODE_SENDONCETHENDELETE), 'OR');
        $mode_criteria->add (new Criteria('not_mode', XOOPS_NOTIFICATION_MODE_SENDONCETHENWAIT), 'OR');
        $criteria->add($mode_criteria);
        if (!empty($user_list)) {
            $user_criteria = new CriteriaCompo();
            foreach ($user_list as $user) {
                $user_criteria->add (new Criteria('not_uid', $user), 'OR');
            }
            $criteria->add($user_criteria);
        }
        $notifications =& $this->getObjects($criteria);
        if (empty($notifications)) {
            return;
        }

        // Add some tag substitutions here

        $not_config = $module->getInfo('notification');
        $tags = array();
        if (!empty($not_config)) {
            if (!empty($not_config['tags_file'])) {
                $tags_file = XOOPS_ROOT_PATH . '/modules/' . $module->getVar('dirname') . '/' . $not_config['tags_file'];
                if (file_exists($tags_file)) {
                    include_once $tags_file;
                    if (!empty($not_config['tags_func'])) {
                        $tags_func = $not_config['tags_func'];
                        if (function_exists($tags_func)) {
                            $tags = $tags_func($category, intval($item_id), $event);
                        }
                    }
                }
            }
            // RMV-NEW
            if (!empty($not_config['lookup_file'])) {
                $lookup_file = XOOPS_ROOT_PATH . '/modules/' . $module->getVar('dirname') . '/' . $not_config['lookup_file'];
                if (file_exists($lookup_file)) {
                    include_once $lookup_file;
                    if (!empty($not_config['lookup_func'])) {
                        $lookup_func = $not_config['lookup_func'];
                        if (function_exists($lookup_func)) {
                            $item_info = $lookup_func($category, intval($item_id));
                        }
                    }
                }
            }
        }
        $tags['X_ITEM_NAME'] = !empty($item_info['name']) ? $item_info['name'] : '[' . _NOT_ITEMNAMENOTAVAILABLE . ']';
        $tags['X_ITEM_URL']  = !empty($item_info['url']) ? $item_info['url'] : '[' . _NOT_ITEMURLNOTAVAILABLE . ']';
        $tags['X_ITEM_TYPE'] = !empty($category_info['item_name']) ? $category_info['title'] : '[' . _NOT_ITEMTYPENOTAVAILABLE . ']';
        $tags['X_MODULE'] = $module->getVar('name');
        $tags['X_MODULE_URL'] = XOOPS_URL . '/modules/' . $module->getVar('dirname') . '/';
        $tags['X_NOTIFY_CATEGORY'] = $category;
        $tags['X_NOTIFY_EVENT'] = $event;

        $template_dir = $event_info['mail_template_dir'];
        $template = $event_info['mail_template'] . '.tpl';
        $subject = $event_info['mail_subject'];

        foreach ($notifications as $notification) {
            if (empty($omit_user_id) || $notification->getVar('not_uid') != $omit_user_id) {
                // user-specific tags
                //$tags['X_UNSUBSCRIBE_URL'] = 'TODO';
                // TODO: don't show unsubscribe link if it is 'one-time' ??
                $tags['X_UNSUBSCRIBE_URL'] = XOOPS_URL . '/notifications.php';
                $tags = array_merge ($tags, $extra_tags);

                $notification->notifyUser($template_dir, $template, $subject, $tags);
            }
        }
    }

    /**
     * Delete all notifications for one user
     *
     * @param   int $user_id  ID of the user
     * @return  bool
     **/
    function unsubscribeByUser ($user_id)
    {
        $criteria = new Criteria('not_uid', intval($user_id));
        return $this->deleteAll($criteria);
    }

// TODO: allow these to use current module, etc...

    /**
     * Unsubscribe notifications for an event(s).
     *
     * @param  string  $category    category of the events
     * @param  int     $item_id     ID of the item
     * @param  mixed   $events      event string or array of events
     * @param  int     $module_id   ID of the module (default current module)
     * @param  int     $user_id     UID of the user (default current user)
     *
     * @return bool
     **/

    function unsubscribe ($category, $item_id, $events, $module_id=null, $user_id=null)
    {
        if (!isset($user_id)) {
            global $xoopsUser;
            if (empty($xoopsUser)) {
                return false;  // anonymous cannot subscribe
            } else {
                $user_id = $xoopsUser->getVar('uid');
            }
        }

        if (!isset($module_id)) {
            global $xoopsModule;
            $module_id = $xoopsModule->getVar('mid');
        }

        $criteria = new CriteriaCompo();
        $criteria->add (new Criteria('not_modid', intval($module_id)));
        $criteria->add (new Criteria('not_category', $category));
        $criteria->add (new Criteria('not_itemid', intval($item_id)));
        $criteria->add (new Criteria('not_uid', intval($user_id)));
        if (!is_array($events)) {
            $events = array($events);
        }
        $event_criteria = new CriteriaCompo();
        foreach ($events as $event) {
            $event_criteria->add (new Criteria('not_event', $event), 'OR');
        }
        $criteria->add($event_criteria);
        return $this->deleteAll($criteria);
    }

    // TODO: When 'update' a module, may need to switch around some
    //  notification classes/IDs...  or delete the ones that no longer
    //  exist.

    /**
     * Delete all notifications for a particular module
     *
     * @param   int $module_id  ID of the module
     * @return  bool
     **/
    function unsubscribeByModule ($module_id)
    {
        $criteria = new Criteria('not_modid', intval($module_id));
        return $this->deleteAll($criteria);
    }

    /**
     * Delete all subscriptions for a particular item.
     *
     * @param  int    $module_id  ID of the module to which item belongs
     * @param  string $category   Notification category of the item
     * @param  int    $item_id    ID of the item
     *
     * @return bool
     **/
    function unsubscribeByItem ($module_id, $category, $item_id)
    {
        $criteria = new CriteriaCompo();
        $criteria->add (new Criteria('not_modid', intval($module_id)));
        $criteria->add (new Criteria('not_category', $category));
        $criteria->add (new Criteria('not_itemid', intval($item_id)));
        return $this->deleteAll($criteria);
    }

    /**
     * Perform notification maintenance activites at login time.
     * In particular, any notifications for the newly logged-in
     * user with mode XOOPS_NOTIFICATION_MODE_WAITFORLOGIN are
     * switched to mode XOOPS_NOTIFICATION_MODE_SENDONCETHENWAIT.
     *
     * @param  int  $user_id  ID of the user being logged in
     **/
    function doLoginMaintenance ($user_id)
    {
        $criteria = new CriteriaCompo();
        $criteria->add (new Criteria('not_uid', intval($user_id)));
        $criteria->add (new Criteria('not_mode', XOOPS_NOTIFICATION_MODE_WAITFORLOGIN));

        $notifications = $this->getObjects($criteria, true);
        foreach ($notifications as $n) {
            $n->setVar('not_mode', XOOPS_NOTIFICATION_MODE_SENDONCETHENWAIT);
            $this->insert($n);
        }
    }

    /**
     * Update
     *
     * @param   object  &$notification  {@link XoopsNotification} object
     * @param   string  $field_name     Name of the field
     * @param   mixed   $field_value    Value to write
     *
     * @return  bool
     **/
    function updateByField(&$notification, $field_name, $field_value)
    {
        $notification->unsetNew();
        $notification->setVar($field_name, $field_value);
        return $this->insert($notification);
    }
}
?>