<?php
/**
 * StatusNet - the distributed open-source microblogging tool
 * Copyright (C) 2008, 2009, StatusNet, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.     If not, see <http://www.gnu.org/licenses/>.
 *
 * @category Notices
 * @package  StatusNet
 * @author   Brenda Wallace <shiny@cpan.org>
 * @author   Christopher Vollick <psycotica0@gmail.com>
 * @author   CiaranG <ciaran@ciarang.com>
 * @author   Craig Andrews <candrews@integralblue.com>
 * @author   Evan Prodromou <evan@controlezvous.ca>
 * @author   Gina Haeussge <osd@foosel.net>
 * @author   Jeffery To <jeffery.to@gmail.com>
 * @author   Mike Cochrane <mikec@mikenz.geek.nz>
 * @author   Robin Millette <millette@controlyourself.ca>
 * @author   Sarven Capadisli <csarven@controlyourself.ca>
 * @author   Tom Adams <tom@holizz.com>
 * @copyright 2009 Free Software Foundation, Inc http://www.fsf.org
 * @license  GNU Affero General Public License http://www.gnu.org/licenses/
 */

if (!defined('STATUSNET') && !defined('LACONICA')) {
    exit(1);
}

/**
 * Table Definition for notice
 */
require_once INSTALLDIR.'/classes/Memcached_DataObject.php';

/* We keep 200 notices, the max number of notices available per API request,
 * in the memcached cache. */

define('NOTICE_CACHE_WINDOW', CachingNoticeStream::CACHE_WINDOW);

define('MAX_BOXCARS', 128);

class Notice extends Memcached_DataObject
{
    ###START_AUTOCODE
    /* the code below is auto generated do not remove the above tag */

    public $__table = 'notice';                          // table name
    public $id;                              // int(4)  primary_key not_null
    public $profile_id;                      // int(4)  multiple_key not_null
    public $uri;                             // varchar(255)  unique_key
    public $content;                         // text
    public $rendered;                        // text
    public $url;                             // varchar(255)
    public $created;                         // datetime  multiple_key not_null default_0000-00-00%2000%3A00%3A00
    public $modified;                        // timestamp   not_null default_CURRENT_TIMESTAMP
    public $reply_to;                        // int(4)
    public $is_local;                        // int(4)
    public $source;                          // varchar(32)
    public $conversation;                    // int(4)
    public $lat;                             // decimal(10,7)
    public $lon;                             // decimal(10,7)
    public $location_id;                     // int(4)
    public $location_ns;                     // int(4)
    public $repeat_of;                       // int(4)
    public $object_type;                     // varchar(255)
    public $scope;                           // int(4)

    /* Static get */
    function staticGet($k,$v=NULL)
    {
        return Memcached_DataObject::staticGet('Notice',$k,$v);
    }

    /* the code above is auto generated do not remove the tag below */
    ###END_AUTOCODE

    /* Notice types */
    const LOCAL_PUBLIC    =  1;
    const REMOTE_OMB      =  0;
    const LOCAL_NONPUBLIC = -1;
    const GATEWAY         = -2;

    const PUBLIC_SCOPE    = 0; // Useful fake constant
    const SITE_SCOPE      = 1;
    const ADDRESSEE_SCOPE = 2;
    const GROUP_SCOPE     = 4;
    const FOLLOWER_SCOPE  = 8;

    protected $_profile = -1;

    function getProfile()
    {
        if ($this->_profile == -1) {
            $this->_profile = Profile::staticGet('id', $this->profile_id);

            if (empty($this->_profile)) {
                // TRANS: Server exception thrown when a user profile for a notice cannot be found.
                // TRANS: %1$d is a profile ID (number), %2$d is a notice ID (number).
                throw new ServerException(sprintf(_('No such profile (%1$d) for notice (%2$d).'), $this->profile_id, $this->id));
            }
        }

        return $this->_profile;
    }

    function delete()
    {
        // For auditing purposes, save a record that the notice
        // was deleted.

        // @fixme we have some cases where things get re-run and so the
        // insert fails.
        $deleted = Deleted_notice::staticGet('id', $this->id);

        if (!$deleted) {
            $deleted = Deleted_notice::staticGet('uri', $this->uri);
        }

        if (!$deleted) {
            $deleted = new Deleted_notice();

            $deleted->id         = $this->id;
            $deleted->profile_id = $this->profile_id;
            $deleted->uri        = $this->uri;
            $deleted->created    = $this->created;
            $deleted->deleted    = common_sql_now();

            $deleted->insert();
        }

        if (Event::handle('NoticeDeleteRelated', array($this))) {

            // Clear related records

            $this->clearReplies();
            $this->clearRepeats();
            $this->clearFaves();
            $this->clearTags();
            $this->clearGroupInboxes();
            $this->clearFiles();

            // NOTE: we don't clear inboxes
            // NOTE: we don't clear queue items
        }

        $result = parent::delete();

        $this->blowOnDelete();
        return $result;
    }

    /**
     * Extract #hashtags from this notice's content and save them to the database.
     */
    function saveTags()
    {
        /* extract all #hastags */
        $count = preg_match_all('/(?:^|\s)#([\pL\pN_\-\.]{1,64})/u', strtolower($this->content), $match);
        if (!$count) {
            return true;
        }

        /* Add them to the database */
        return $this->saveKnownTags($match[1]);
    }

    /**
     * Record the given set of hash tags in the db for this notice.
     * Given tag strings will be normalized and checked for dupes.
     */
    function saveKnownTags($hashtags)
    {
        //turn each into their canonical tag
        //this is needed to remove dupes before saving e.g. #hash.tag = #hashtag
        for($i=0; $i<count($hashtags); $i++) {
            /* elide characters we don't want in the tag */
            $hashtags[$i] = common_canonical_tag($hashtags[$i]);
        }

        foreach(array_unique($hashtags) as $hashtag) {
            $this->saveTag($hashtag);
            self::blow('profile:notice_ids_tagged:%d:%s', $this->profile_id, $hashtag);
        }
        return true;
    }

    /**
     * Record a single hash tag as associated with this notice.
     * Tag format and uniqueness must be validated by caller.
     */
    function saveTag($hashtag)
    {
        $tag = new Notice_tag();
        $tag->notice_id = $this->id;
        $tag->tag = $hashtag;
        $tag->created = $this->created;
        $id = $tag->insert();

        if (!$id) {
            // TRANS: Server exception. %s are the error details.
            throw new ServerException(sprintf(_('Database error inserting hashtag: %s'),
                                              $last_error->message));
            return;
        }

        // if it's saved, blow its cache
        $tag->blowCache(false);
    }

    /**
     * Save a new notice and push it out to subscribers' inboxes.
     * Poster's permissions are checked before sending.
     *
     * @param int $profile_id Profile ID of the poster
     * @param string $content source message text; links may be shortened
     *                        per current user's preference
     * @param string $source source key ('web', 'api', etc)
     * @param array $options Associative array of optional properties:
     *              string 'created' timestamp of notice; defaults to now
     *              int 'is_local' source/gateway ID, one of:
     *                  Notice::LOCAL_PUBLIC    - Local, ok to appear in public timeline
     *                  Notice::REMOTE_OMB      - Sent from a remote OMB service;
     *                                            hide from public timeline but show in
     *                                            local "and friends" timelines
     *                  Notice::LOCAL_NONPUBLIC - Local, but hide from public timeline
     *                  Notice::GATEWAY         - From another non-OMB service;
     *                                            will not appear in public views
     *              float 'lat' decimal latitude for geolocation
     *              float 'lon' decimal longitude for geolocation
     *              int 'location_id' geoname identifier
     *              int 'location_ns' geoname namespace to interpret location_id
     *              int 'reply_to'; notice ID this is a reply to
     *              int 'repeat_of'; notice ID this is a repeat of
     *              string 'uri' unique ID for notice; defaults to local notice URL
     *              string 'url' permalink to notice; defaults to local notice URL
     *              string 'rendered' rendered HTML version of content
     *              array 'replies' list of profile URIs for reply delivery in
     *                              place of extracting @-replies from content.
     *              array 'groups' list of group IDs to deliver to, in place of
     *                              extracting ! tags from content
     *              array 'tags' list of hashtag strings to save with the notice
     *                           in place of extracting # tags from content
     *              array 'urls' list of attached/referred URLs to save with the
     *                           notice in place of extracting links from content
     *              boolean 'distribute' whether to distribute the notice, default true
     *              string 'object_type' URL of the associated object type (default ActivityObject::NOTE)
     *              int 'scope' Scope bitmask; default to SITE_SCOPE on private sites, 0 otherwise
     *
     * @fixme tag override
     *
     * @return Notice
     * @throws ClientException
     */
    static function saveNew($profile_id, $content, $source, $options=null) {
        $defaults = array('uri' => null,
                          'url' => null,
                          'reply_to' => null,
                          'repeat_of' => null,
                          'scope' => null,
                          'distribute' => true);

        if (!empty($options)) {
            $options = $options + $defaults;
            extract($options);
        } else {
            extract($defaults);
        }

        if (!isset($is_local)) {
            $is_local = Notice::LOCAL_PUBLIC;
        }

        $profile = Profile::staticGet('id', $profile_id);
        $user = User::staticGet('id', $profile_id);
        if ($user) {
            // Use the local user's shortening preferences, if applicable.
            $final = $user->shortenLinks($content);
        } else {
            $final = common_shorten_links($content);
        }

        if (Notice::contentTooLong($final)) {
            // TRANS: Client exception thrown if a notice contains too many characters.
            throw new ClientException(_('Problem saving notice. Too long.'));
        }

        if (empty($profile)) {
            // TRANS: Client exception thrown when trying to save a notice for an unknown user.
            throw new ClientException(_('Problem saving notice. Unknown user.'));
        }

        if (common_config('throttle', 'enabled') && !Notice::checkEditThrottle($profile_id)) {
            common_log(LOG_WARNING, 'Excessive posting by profile #' . $profile_id . '; throttled.');
            // TRANS: Client exception thrown when a user tries to post too many notices in a given time frame.
            throw new ClientException(_('Too many notices too fast; take a breather '.
                                        'and post again in a few minutes.'));
        }

        if (common_config('site', 'dupelimit') > 0 && !Notice::checkDupes($profile_id, $final)) {
            common_log(LOG_WARNING, 'Dupe posting by profile #' . $profile_id . '; throttled.');
            // TRANS: Client exception thrown when a user tries to post too many duplicate notices in a given time frame.
            throw new ClientException(_('Too many duplicate messages too quickly;'.
                                        ' take a breather and post again in a few minutes.'));
        }

        if (!$profile->hasRight(Right::NEWNOTICE)) {
            common_log(LOG_WARNING, "Attempted post from user disallowed to post: " . $profile->nickname);

            // TRANS: Client exception thrown when a user tries to post while being banned.
            throw new ClientException(_('You are banned from posting notices on this site.'), 403);
        }

        $notice = new Notice();
        $notice->profile_id = $profile_id;

        $autosource = common_config('public', 'autosource');

        // Sandboxed are non-false, but not 1, either

        if (!$profile->hasRight(Right::PUBLICNOTICE) ||
            ($source && $autosource && in_array($source, $autosource))) {
            $notice->is_local = Notice::LOCAL_NONPUBLIC;
        } else {
            $notice->is_local = $is_local;
        }

        if (!empty($created)) {
            $notice->created = $created;
        } else {
            $notice->created = common_sql_now();
        }

        $notice->content = $final;

        $notice->source = $source;
        $notice->uri = $uri;
        $notice->url = $url;

        // Get the groups here so we can figure out replies and such

        if (!isset($groups)) {
            $groups = self::groupsFromText($notice->content, $profile);
        }

        $reply = null;

        // Handle repeat case

        if (isset($repeat_of)) {

            // Check for a private one

            $repeat = Notice::staticGet('id', $repeat_of);

            if (empty($repeat)) {
                // TRANS: Client exception thrown in notice when trying to repeat a missing or deleted notice.
                throw new ClientException(_('Cannot repeat; original notice is missing or deleted.'));
            }

            if ($profile->id == $repeat->profile_id) {
                // TRANS: Client error displayed when trying to repeat an own notice.
                throw new ClientException(_('You cannot repeat your own notice.'));
            }

            if ($repeat->scope != Notice::SITE_SCOPE &&
                $repeat->scope != Notice::PUBLIC_SCOPE) {
                // TRANS: Client error displayed when trying to repeat a non-public notice.
                throw new ClientException(_('Cannot repeat a private notice.'), 403);
            }

            if (!$repeat->inScope($profile)) {
                // The generic checks above should cover this, but let's be sure!
                // TRANS: Client error displayed when trying to repeat a notice you cannot access.
                throw new ClientException(_('Cannot repeat a notice you cannot read.'), 403);
            }

            if ($profile->hasRepeated($repeat->id)) {
                // TRANS: Client error displayed when trying to repeat an already repeated notice.
                throw new ClientException(_('You already repeated that notice.'));
            }

            $notice->repeat_of = $repeat_of;
        } else {
            $reply = self::getReplyTo($reply_to, $profile_id, $source, $final);

            if (!empty($reply)) {

                if (!$reply->inScope($profile)) {
                    // TRANS: Client error displayed when trying to reply to a notice a the target has no access to.
                    // TRANS: %1$s is a user nickname, %2$d is a notice ID (number).
                    throw new ClientException(sprintf(_('%1$s has no access to notice %2$d.'),
                                                      $profile->nickname, $reply->id), 403);
                }

                $notice->reply_to     = $reply->id;
                $notice->conversation = $reply->conversation;

                // If the original is private to a group, and notice has no group specified,
                // make it to the same group(s)

                if (empty($groups) && ($reply->scope | Notice::GROUP_SCOPE)) {
                    $groups = array();
                    $replyGroups = $reply->getGroups();
                    foreach ($replyGroups as $group) {
                        if ($profile->isMember($group)) {
                            $groups[] = $group->id;
                        }
                    }
                }

                // Scope set below
            }
        }

        if (!empty($lat) && !empty($lon)) {
            $notice->lat = $lat;
            $notice->lon = $lon;
        }

        if (!empty($location_ns) && !empty($location_id)) {
            $notice->location_id = $location_id;
            $notice->location_ns = $location_ns;
        }

        if (!empty($rendered)) {
            $notice->rendered = $rendered;
        } else {
            $notice->rendered = common_render_content($final, $notice);
        }

        if (empty($object_type)) {
            $notice->object_type = (empty($notice->reply_to)) ? ActivityObject::NOTE : ActivityObject::COMMENT;
        } else {
            $notice->object_type = $object_type;
        }

        if (is_null($scope)) { // 0 is a valid value
            if (!empty($reply)) {
                $notice->scope = $reply->scope;
            } else {
                $notice->scope = common_config('notice', 'defaultscope');
            }
        } else {
            $notice->scope = $scope;
        }

        // For private streams

        $user = $profile->getUser();

        if (!empty($user)) {
            if ($user->private_stream &&
                ($notice->scope == Notice::PUBLIC_SCOPE ||
                 $notice->scope == Notice::SITE_SCOPE)) {
                $notice->scope |= Notice::FOLLOWER_SCOPE;
            }
        }

        // Force the scope for private groups

        foreach ($groups as $groupId) {
            $group = User_group::staticGet('id', $groupId);
            if (!empty($group)) {
                if ($group->force_scope) {
                    $notice->scope |= Notice::GROUP_SCOPE;
                    break;
                }
            }
        }

        if (Event::handle('StartNoticeSave', array(&$notice))) {

            // XXX: some of these functions write to the DB

            $id = $notice->insert();

            if (!$id) {
                common_log_db_error($notice, 'INSERT', __FILE__);
                // TRANS: Server exception thrown when a notice cannot be saved.
                throw new ServerException(_('Problem saving notice.'));
            }

            // Update ID-dependent columns: URI, conversation

            $orig = clone($notice);

            $changed = false;

            if (empty($uri)) {
                $notice->uri = common_notice_uri($notice);
                $changed = true;
            }

            // If it's not part of a conversation, it's
            // the beginning of a new conversation.

            if (empty($notice->conversation)) {
                $conv = Conversation::create();
                $notice->conversation = $conv->id;
                $changed = true;
            }

            if ($changed) {
                if (!$notice->update($orig)) {
                    common_log_db_error($notice, 'UPDATE', __FILE__);
                    // TRANS: Server exception thrown when a notice cannot be updated.
                    throw new ServerException(_('Problem saving notice.'));
                }
            }

        }

        // Clear the cache for subscribed users, so they'll update at next request
        // XXX: someone clever could prepend instead of clearing the cache

        $notice->blowOnInsert();

        // Save per-notice metadata...

        if (isset($replies)) {
            $notice->saveKnownReplies($replies);
        } else {
            $notice->saveReplies();
        }

        if (isset($tags)) {
            $notice->saveKnownTags($tags);
        } else {
            $notice->saveTags();
        }

        // Note: groups may save tags, so must be run after tags are saved
        // to avoid errors on duplicates.
        // Note: groups should always be set.

        $notice->saveKnownGroups($groups);

        if (isset($peopletags)) {
            $notice->saveProfileTags($peopletags);
        } else {
            $notice->saveProfileTags();
        }

        if (isset($urls)) {
            $notice->saveKnownUrls($urls);
        } else {
            $notice->saveUrls();
        }

        if ($distribute) {
            // Prepare inbox delivery, may be queued to background.
            $notice->distribute();
        }

        return $notice;
    }

    function blowOnInsert($conversation = false)
    {
        self::blow('profile:notice_ids:%d', $this->profile_id);

        if ($this->isPublic()) {
            self::blow('public');
        }

        // XXX: Before we were blowing the casche only if the notice id
        // was not the root of the conversation.  What to do now?

        self::blow('notice:conversation_ids:%d', $this->conversation);
        self::blow('conversation::notice_count:%d', $this->conversation);

        if (!empty($this->repeat_of)) {
            self::blow('notice:repeats:%d', $this->repeat_of);
        }

        $original = Notice::staticGet('id', $this->repeat_of);

        if (!empty($original)) {
            $originalUser = User::staticGet('id', $original->profile_id);
            if (!empty($originalUser)) {
                self::blow('user:repeats_of_me:%d', $originalUser->id);
            }
        }

        $profile = Profile::staticGet($this->profile_id);
        if (!empty($profile)) {
            $profile->blowNoticeCount();
        }
    }

    /**
     * Clear cache entries related to this notice at delete time.
     * Necessary to avoid breaking paging on public, profile timelines.
     */
    function blowOnDelete()
    {
        $this->blowOnInsert();

        self::blow('profile:notice_ids:%d;last', $this->profile_id);

        if ($this->isPublic()) {
            self::blow('public;last');
        }

        self::blow('fave:by_notice', $this->id);

        if ($this->conversation) {
            // In case we're the first, will need to calc a new root.
            self::blow('notice:conversation_root:%d', $this->conversation);
        }
    }

    /** save all urls in the notice to the db
     *
     * follow redirects and save all available file information
     * (mimetype, date, size, oembed, etc.)
     *
     * @return void
     */
    function saveUrls() {
        if (common_config('attachments', 'process_links')) {
            common_replace_urls_callback($this->content, array($this, 'saveUrl'), $this->id);
        }
    }

    /**
     * Save the given URLs as related links/attachments to the db
     *
     * follow redirects and save all available file information
     * (mimetype, date, size, oembed, etc.)
     *
     * @return void
     */
    function saveKnownUrls($urls)
    {
        if (common_config('attachments', 'process_links')) {
            // @fixme validation?
            foreach (array_unique($urls) as $url) {
                File::processNew($url, $this->id);
            }
        }
    }

    /**
     * @private callback
     */
    function saveUrl($url, $notice_id) {
        File::processNew($url, $notice_id);
    }

    static function checkDupes($profile_id, $content) {
        $profile = Profile::staticGet($profile_id);
        if (empty($profile)) {
            return false;
        }
        $notice = $profile->getNotices(0, CachingNoticeStream::CACHE_WINDOW);
        if (!empty($notice)) {
            $last = 0;
            while ($notice->fetch()) {
                if (time() - strtotime($notice->created) >= common_config('site', 'dupelimit')) {
                    return true;
                } else if ($notice->content == $content) {
                    return false;
                }
            }
        }
        // If we get here, oldest item in cache window is not
        // old enough for dupe limit; do direct check against DB
        $notice = new Notice();
        $notice->profile_id = $profile_id;
        $notice->content = $content;
        $threshold = common_sql_date(time() - common_config('site', 'dupelimit'));
        $notice->whereAdd(sprintf("created > '%s'", $notice->escape($threshold)));

        $cnt = $notice->count();
        return ($cnt == 0);
    }

    static function checkEditThrottle($profile_id) {
        $profile = Profile::staticGet($profile_id);
        if (empty($profile)) {
            return false;
        }
        // Get the Nth notice
        $notice = $profile->getNotices(common_config('throttle', 'count') - 1, 1);
        if ($notice && $notice->fetch()) {
            // If the Nth notice was posted less than timespan seconds ago
            if (time() - strtotime($notice->created) <= common_config('throttle', 'timespan')) {
                // Then we throttle
                return false;
            }
        }
        // Either not N notices in the stream, OR the Nth was not posted within timespan seconds
        return true;
    }

    function getUploadedAttachment() {
        $post = clone $this;
        $query = 'select file.url as up, file.id as i from file join file_to_post on file.id = file_id where post_id=' . $post->escape($post->id) . ' and url like "%/notice/%/file"';
        $post->query($query);
        $post->fetch();
        if (empty($post->up) || empty($post->i)) {
            $ret = false;
        } else {
            $ret = array($post->up, $post->i);
        }
        $post->free();
        return $ret;
    }

    function hasAttachments() {
        $post = clone $this;
        $query = "select count(file_id) as n_attachments from file join file_to_post on (file_id = file.id) join notice on (post_id = notice.id) where post_id = " . $post->escape($post->id);
        $post->query($query);
        $post->fetch();
        $n_attachments = intval($post->n_attachments);
        $post->free();
        return $n_attachments;
    }

    function attachments() {

        $keypart = sprintf('notice:file_ids:%d', $this->id);

        $idstr = self::cacheGet($keypart);

        if ($idstr !== false) {
            $ids = explode(',', $idstr);
        } else {
            $ids = array();
            $f2p = new File_to_post;
            $f2p->post_id = $this->id;
            if ($f2p->find()) {
                while ($f2p->fetch()) {
                    $ids[] = $f2p->file_id;
                }
            }
            self::cacheSet($keypart, implode(',', $ids));
        }

        $att = array();

        foreach ($ids as $id) {
            $f = File::staticGet('id', $id);
            if (!empty($f)) {
                $att[] = clone($f);
            }
        }

        return $att;
    }


    function publicStream($offset=0, $limit=20, $since_id=0, $max_id=0)
    {
        $stream = new PublicNoticeStream();
        return $stream->getNotices($offset, $limit, $since_id, $max_id);
    }


    function conversationStream($id, $offset=0, $limit=20, $since_id=0, $max_id=0)
    {
        $stream = new ConversationNoticeStream($id);

        return $stream->getNotices($offset, $limit, $since_id, $max_id);
    }

    /**
     * Is this notice part of an active conversation?
     *
     * @return boolean true if other messages exist in the same
     *                 conversation, false if this is the only one
     */
    function hasConversation()
    {
        if (!empty($this->conversation)) {
            $conversation = Notice::conversationStream(
                $this->conversation,
                1,
                1
            );

            if ($conversation->N > 0) {
                return true;
            }
        }
        return false;
    }

    /**
     * Grab the earliest notice from this conversation.
     *
     * @return Notice or null
     */
    function conversationRoot()
    {
        if (!empty($this->conversation)) {
            $c = self::memcache();

            $key = Cache::key('notice:conversation_root:' . $this->conversation);
            $notice = $c->get($key);
            if ($notice) {
                return $notice;
            }

            $notice = new Notice();
            $notice->conversation = $this->conversation;
            $notice->orderBy('CREATED');
            $notice->limit(1);
            $notice->find(true);

            if ($notice->N) {
                $c->set($key, $notice);
                return $notice;
            }
        }
        return null;
    }
    /**
     * Pull up a full list of local recipients who will be getting
     * this notice in their inbox. Results will be cached, so don't
     * change the input data wily-nilly!
     *
     * @param array $groups optional list of Group objects;
     *              if left empty, will be loaded from group_inbox records
     * @param array $recipient optional list of reply profile ids
     *              if left empty, will be loaded from reply records
     * @return array associating recipient user IDs with an inbox source constant
     */
    function whoGets($groups=null, $recipients=null)
    {
        $c = self::memcache();

        if (!empty($c)) {
            $ni = $c->get(Cache::key('notice:who_gets:'.$this->id));
            if ($ni !== false) {
                return $ni;
            }
        }

        if (is_null($groups)) {
            $groups = $this->getGroups();
        }

        if (is_null($recipients)) {
            $recipients = $this->getReplies();
        }

        $users = $this->getSubscribedUsers();
        $ptags = $this->getProfileTags();

        // FIXME: kind of ignoring 'transitional'...
        // we'll probably stop supporting inboxless mode
        // in 0.9.x

        $ni = array();

        // Give plugins a chance to add folks in at start...
        if (Event::handle('StartNoticeWhoGets', array($this, &$ni))) {

            foreach ($users as $id) {
                $ni[$id] = NOTICE_INBOX_SOURCE_SUB;
            }

            foreach ($groups as $group) {
                $users = $group->getUserMembers();
                foreach ($users as $id) {
                    if (!array_key_exists($id, $ni)) {
                        $ni[$id] = NOTICE_INBOX_SOURCE_GROUP;
                    }
                }
            }

            foreach ($ptags as $ptag) {
                $users = $ptag->getUserSubscribers();
                foreach ($users as $id) {
                    if (!array_key_exists($id, $ni)) {
                        $user = User::staticGet('id', $id);
                        if (!$user->hasBlocked($profile)) {
                            $ni[$id] = NOTICE_INBOX_SOURCE_PROFILE_TAG;
                        }
                    }
                }
            }

            foreach ($recipients as $recipient) {
                if (!array_key_exists($recipient, $ni)) {
                    $ni[$recipient] = NOTICE_INBOX_SOURCE_REPLY;
                }

                // Exclude any deleted, non-local, or blocking recipients.
                $profile = $this->getProfile();
                $originalProfile = null;
                if ($this->repeat_of) {
                    // Check blocks against the original notice's poster as well.
                    $original = Notice::staticGet('id', $this->repeat_of);
                    if ($original) {
                        $originalProfile = $original->getProfile();
                    }
                }
                foreach ($ni as $id => $source) {
                    $user = User::staticGet('id', $id);
                    if (empty($user) || $user->hasBlocked($profile) ||
                        ($originalProfile && $user->hasBlocked($originalProfile))) {
                        unset($ni[$id]);
                    }
                }
            }

            // Give plugins a chance to filter out...
            Event::handle('EndNoticeWhoGets', array($this, &$ni));
        }

        if (!empty($c)) {
            // XXX: pack this data better
            $c->set(Cache::key('notice:who_gets:'.$this->id), $ni);
        }

        return $ni;
    }

    /**
     * Adds this notice to the inboxes of each local user who should receive
     * it, based on author subscriptions, group memberships, and @-replies.
     *
     * Warning: running a second time currently will make items appear
     * multiple times in users' inboxes.
     *
     * @fixme make more robust against errors
     * @fixme break up massive deliveries to smaller background tasks
     *
     * @param array $groups optional list of Group objects;
     *              if left empty, will be loaded from group_inbox records
     * @param array $recipient optional list of reply profile ids
     *              if left empty, will be loaded from reply records
     */
    function addToInboxes($groups=null, $recipients=null)
    {
        $ni = $this->whoGets($groups, $recipients);

        $ids = array_keys($ni);

        // We remove the author (if they're a local user),
        // since we'll have already done this in distribute()

        $i = array_search($this->profile_id, $ids);

        if ($i !== false) {
            unset($ids[$i]);
        }

        // Bulk insert

        Inbox::bulkInsert($this->id, $ids);

        return;
    }

    function getSubscribedUsers()
    {
        $user = new User();

        if(common_config('db','quote_identifiers'))
          $user_table = '"user"';
        else $user_table = 'user';

        $qry =
          'SELECT id ' .
          'FROM '. $user_table .' JOIN subscription '.
          'ON '. $user_table .'.id = subscription.subscriber ' .
          'WHERE subscription.subscribed = %d ';

        $user->query(sprintf($qry, $this->profile_id));

        $ids = array();

        while ($user->fetch()) {
            $ids[] = $user->id;
        }

        $user->free();

        return $ids;
    }

    function getProfileTags()
    {
        // Don't save ptags for repeats, for now.

        if (!empty($this->repeat_of)) {
            return array();
        }

        // XXX: cache me

        $ptags = array();

        $ptagi = new Profile_tag_inbox();

        $ptagi->selectAdd();
        $ptagi->selectAdd('profile_tag_id');

        $ptagi->notice_id = $this->id;

        if ($ptagi->find()) {
            while ($ptagi->fetch()) {
                $profile_list = Profile_list::staticGet('id', $ptagi->profile_tag_id);
                if ($profile_list) {
                    $ptags[] = $profile_list;
                }
            }
        }

        $ptagi->free();

        return $ptags;
    }

    /**
     * Record this notice to the given group inboxes for delivery.
     * Overrides the regular parsing of !group markup.
     *
     * @param string $group_ids
     * @fixme might prefer URIs as identifiers, as for replies?
     *        best with generalizations on user_group to support
     *        remote groups better.
     */
    function saveKnownGroups($group_ids)
    {
        if (!is_array($group_ids)) {
            // TRANS: Server exception thrown when no array is provided to the method saveKnownGroups().
            throw new ServerException(_('Bad type provided to saveKnownGroups.'));
        }

        $groups = array();
        foreach (array_unique($group_ids) as $id) {
            $group = User_group::staticGet('id', $id);
            if ($group) {
                common_log(LOG_ERR, "Local delivery to group id $id, $group->nickname");
                $result = $this->addToGroupInbox($group);
                if (!$result) {
                    common_log_db_error($gi, 'INSERT', __FILE__);
                }

                // we automatically add a tag for every group name, too

                $tag = Notice_tag::pkeyGet(array('tag' => common_canonical_tag($group->nickname),
                                                 'notice_id' => $this->id));

                if (is_null($tag)) {
                    $this->saveTag($group->nickname);
                }

                $groups[] = clone($group);
            } else {
                common_log(LOG_ERR, "Local delivery to group id $id skipped, doesn't exist");
            }
        }

        return $groups;
    }

    /**
     * Parse !group delivery and record targets into group_inbox.
     * @return array of Group objects
     */
    function saveGroups()
    {
        // Don't save groups for repeats

        if (!empty($this->repeat_of)) {
            return array();
        }

        $profile = $this->getProfile();

        $groups = self::groupsFromText($this->content, $profile);

        /* Add them to the database */

        foreach ($groups as $group) {
            /* XXX: remote groups. */

            if (empty($group)) {
                continue;
            }


            if ($profile->isMember($group)) {

                $result = $this->addToGroupInbox($group);

                if (!$result) {
                    common_log_db_error($gi, 'INSERT', __FILE__);
                }

                $groups[] = clone($group);
            }
        }

        return $groups;
    }

    function addToGroupInbox($group)
    {
        $gi = Group_inbox::pkeyGet(array('group_id' => $group->id,
                                         'notice_id' => $this->id));

        if (empty($gi)) {

            $gi = new Group_inbox();

            $gi->group_id  = $group->id;
            $gi->notice_id = $this->id;
            $gi->created   = $this->created;

            $result = $gi->insert();

            if (!$result) {
                common_log_db_error($gi, 'INSERT', __FILE__);
                // TRANS: Server exception thrown when an update for a group inbox fails.
                throw new ServerException(_('Problem saving group inbox.'));
            }

            self::blow('user_group:notice_ids:%d', $gi->group_id);
        }

        return true;
    }

    /**
     * record targets into profile_tag_inbox.
     * @return array of Profile_list objects
     */
    function saveProfileTags($known=array())
    {
        // Don't save ptags for repeats, for now

        if (!empty($this->repeat_of)) {
            return array();
        }

        if (is_array($known)) {
            $ptags = $known;
        } else {
            $ptags = array();
        }

        $ptag = new Profile_tag();
        $ptag->tagged = $this->profile_id;

        if($ptag->find()) {
            while($ptag->fetch()) {
                $plist = Profile_list::getByTaggerAndTag($ptag->tagger, $ptag->tag);
                $ptags[] = clone($plist);
            }
        }

        foreach ($ptags as $target) {
            $this->addToProfileTagInbox($target);
        }

        return $ptags;
    }

    function addToProfileTagInbox($plist)
    {
        $ptagi = Profile_tag_inbox::pkeyGet(array('profile_tag_id' => $plist->id,
                                         'notice_id' => $this->id));

        if (empty($ptagi)) {

            $ptagi = new Profile_tag_inbox();

            $ptagi->query('BEGIN');
            $ptagi->profile_tag_id  = $plist->id;
            $ptagi->notice_id = $this->id;
            $ptagi->created   = $this->created;

            $result = $ptagi->insert();
            if (!$result) {
                common_log_db_error($ptagi, 'INSERT', __FILE__);
                throw new ServerException(_('Problem saving profile_tag inbox.'));
            }

            $ptagi->query('COMMIT');

            self::blow('profile_tag:notice_ids:%d', $ptagi->profile_tag_id);
        }

        return true;
    }

    /**
     * Save reply records indicating that this notice needs to be
     * delivered to the local users with the given URIs.
     *
     * Since this is expected to be used when saving foreign-sourced
     * messages, we won't deliver to any remote targets as that's the
     * source service's responsibility.
     *
     * Mail notifications etc will be handled later.
     *
     * @param array of unique identifier URIs for recipients
     */
    function saveKnownReplies($uris)
    {
        if (empty($uris)) {
            return;
        }

        $sender = Profile::staticGet($this->profile_id);

        foreach (array_unique($uris) as $uri) {

            $profile = Profile::fromURI($uri);

            if (empty($profile)) {
                common_log(LOG_WARNING, "Unable to determine profile for URI '$uri'");
                continue;
            }

            if ($profile->hasBlocked($sender)) {
                common_log(LOG_INFO, "Not saving reply to profile {$profile->id} ($uri) from sender {$sender->id} because of a block.");
                continue;
            }

            $reply = new Reply();

            $reply->notice_id  = $this->id;
            $reply->profile_id = $profile->id;
            $reply->modified   = $this->created;

            common_log(LOG_INFO, __METHOD__ . ": saving reply: notice $this->id to profile $profile->id");

            $id = $reply->insert();
        }

        return;
    }

    /**
     * Pull @-replies from this message's content in StatusNet markup format
     * and save reply records indicating that this message needs to be
     * delivered to those users.
     *
     * Mail notifications to local profiles will be sent later.
     *
     * @return array of integer profile IDs
     */

    function saveReplies()
    {
        // Don't save reply data for repeats

        if (!empty($this->repeat_of)) {
            return array();
        }

        $sender = Profile::staticGet($this->profile_id);

        // @todo ideally this parser information would only
        // be calculated once.

        $mentions = common_find_mentions($this->content, $this);

        $replied = array();

        // store replied only for first @ (what user/notice what the reply directed,
        // we assume first @ is it)

        foreach ($mentions as $mention) {

            foreach ($mention['mentioned'] as $mentioned) {

                // skip if they're already covered

                if (!empty($replied[$mentioned->id])) {
                    continue;
                }

                // Don't save replies from blocked profile to local user

                $mentioned_user = User::staticGet('id', $mentioned->id);
                if (!empty($mentioned_user) && $mentioned_user->hasBlocked($sender)) {
                    continue;
                }

                $reply = new Reply();

                $reply->notice_id  = $this->id;
                $reply->profile_id = $mentioned->id;
                $reply->modified   = $this->created;

                $id = $reply->insert();

                if (!$id) {
                    common_log_db_error($reply, 'INSERT', __FILE__);
                    // TRANS: Server exception thrown when a reply cannot be saved.
                    // TRANS: %1$d is a notice ID, %2$d is the ID of the mentioned user.
                    throw new ServerException(sprintf(_('Could not save reply for %1$d, %2$d.'), $this->id, $mentioned->id));
                } else {
                    $replied[$mentioned->id] = 1;
                    self::blow('reply:stream:%d', $mentioned->id);
                }
            }
        }

        $recipientIds = array_keys($replied);

        return $recipientIds;
    }

    /**
     * Pull the complete list of @-reply targets for this notice.
     *
     * @return array of integer profile ids
     */
    function getReplies()
    {
        $keypart = sprintf('notice:reply_ids:%d', $this->id);

        $idstr = self::cacheGet($keypart);

        if ($idstr !== false) {
            $ids = explode(',', $idstr);
        } else {
            $ids = array();

            $reply = new Reply();
            $reply->selectAdd();
            $reply->selectAdd('profile_id');
            $reply->notice_id = $this->id;

            if ($reply->find()) {
                while($reply->fetch()) {
                    $ids[] = $reply->profile_id;
                }
            }
            self::cacheSet($keypart, implode(',', $ids));
        }

        return $ids;
    }

    /**
     * Send e-mail notifications to local @-reply targets.
     *
     * Replies must already have been saved; this is expected to be run
     * from the distrib queue handler.
     */
    function sendReplyNotifications()
    {
        // Don't send reply notifications for repeats

        if (!empty($this->repeat_of)) {
            return array();
        }

        $recipientIds = $this->getReplies();

        foreach ($recipientIds as $recipientId) {
            $user = User::staticGet('id', $recipientId);
            if (!empty($user)) {
                mail_notify_attn($user, $this);
            }
        }
    }

    /**
     * Pull list of groups this notice needs to be delivered to,
     * as previously recorded by saveGroups() or saveKnownGroups().
     *
     * @return array of Group objects
     */
    function getGroups()
    {
        // Don't save groups for repeats

        if (!empty($this->repeat_of)) {
            return array();
        }

        $ids = array();

        $keypart = sprintf('notice:groups:%d', $this->id);

        $idstr = self::cacheGet($keypart);

        if ($idstr !== false) {
            $ids = explode(',', $idstr);
        } else {
            $gi = new Group_inbox();

            $gi->selectAdd();
            $gi->selectAdd('group_id');

            $gi->notice_id = $this->id;

            if ($gi->find()) {
                while ($gi->fetch()) {
                    $ids[] = $gi->group_id;
                }
            }

            self::cacheSet($keypart, implode(',', $ids));
        }

        $groups = array();

        foreach ($ids as $id) {
            $group = User_group::staticGet('id', $id);
            if ($group) {
                $groups[] = $group;
            }
        }

        return $groups;
    }

    /**
     * Convert a notice into an activity for export.
     *
     * @param User $cur Current user
     *
     * @return Activity activity object representing this Notice.
     */

    function asActivity($cur)
    {
        $act = self::cacheGet(Cache::codeKey('notice:as-activity:'.$this->id));

        if (!empty($act)) {
            return $act;
        }
        $act = new Activity();

        if (Event::handle('StartNoticeAsActivity', array($this, &$act))) {

            $profile = $this->getProfile();

            $act->actor            = ActivityObject::fromProfile($profile);
            $act->actor->extra[]   = $profile->profileInfo($cur);
            $act->verb             = ActivityVerb::POST;
            $act->objects[]        = ActivityObject::fromNotice($this);

            // XXX: should this be handled by default processing for object entry?

            $act->time    = strtotime($this->created);
            $act->link    = $this->bestUrl();

            $act->content = common_xml_safe_str($this->rendered);
            $act->id      = $this->uri;
            $act->title   = common_xml_safe_str($this->content);

            // Categories

            $tags = $this->getTags();

            foreach ($tags as $tag) {
                $cat       = new AtomCategory();
                $cat->term = $tag;

                $act->categories[] = $cat;
            }

            // Enclosures
            // XXX: use Atom Media and/or File activity objects instead

            $attachments = $this->attachments();

            foreach ($attachments as $attachment) {
                $enclosure = $attachment->getEnclosure();
                if ($enclosure) {
                    $act->enclosures[] = $enclosure;
                }
            }

            $ctx = new ActivityContext();

            if (!empty($this->reply_to)) {
                $reply = Notice::staticGet('id', $this->reply_to);
                if (!empty($reply)) {
                    $ctx->replyToID  = $reply->uri;
                    $ctx->replyToUrl = $reply->bestUrl();
                }
            }

            $ctx->location = $this->getLocation();

            $conv = null;

            if (!empty($this->conversation)) {
                $conv = Conversation::staticGet('id', $this->conversation);
                if (!empty($conv)) {
                    $ctx->conversation = $conv->uri;
                }
            }

            $reply_ids = $this->getReplies();

            foreach ($reply_ids as $id) {
                $rprofile = Profile::staticGet('id', $id);
                if (!empty($rprofile)) {
                    $ctx->attention[] = $rprofile->getUri();
                }
            }

            $groups = $this->getGroups();

            foreach ($groups as $group) {
                $ctx->attention[] = $group->getUri();
            }

            // XXX: deprecated; use ActivityVerb::SHARE instead

            $repeat = null;

            if (!empty($this->repeat_of)) {
                $repeat = Notice::staticGet('id', $this->repeat_of);
                $ctx->forwardID  = $repeat->uri;
                $ctx->forwardUrl = $repeat->bestUrl();
            }

            $act->context = $ctx;

            // Source

            $atom_feed = $profile->getAtomFeed();

            if (!empty($atom_feed)) {

                $act->source = new ActivitySource();

                // XXX: we should store the actual feed ID

                $act->source->id = $atom_feed;

                // XXX: we should store the actual feed title

                $act->source->title = $profile->getBestName();

                $act->source->links['alternate'] = $profile->profileurl;
                $act->source->links['self']      = $atom_feed;

                $act->source->icon = $profile->avatarUrl(AVATAR_PROFILE_SIZE);

                $notice = $profile->getCurrentNotice();

                if (!empty($notice)) {
                    $act->source->updated = self::utcDate($notice->created);
                }

                $user = User::staticGet('id', $profile->id);

                if (!empty($user)) {
                    $act->source->links['license'] = common_config('license', 'url');
                }
            }

            if ($this->isLocal()) {
                $act->selfLink = common_local_url('ApiStatusesShow', array('id' => $this->id,
                                                                           'format' => 'atom'));
                $act->editLink = $act->selfLink;
            }

            Event::handle('EndNoticeAsActivity', array($this, &$act));
        }

        self::cacheSet(Cache::codeKey('notice:as-activity:'.$this->id), $act);

        return $act;
    }

    // This has gotten way too long. Needs to be sliced up into functional bits
    // or ideally exported to a utility class.

    function asAtomEntry($namespace=false,
                         $source=false,
                         $author=true,
                         $cur=null)
    {
        $act = $this->asActivity($cur);
        $act->extra[] = $this->noticeInfo($cur);
        return $act->asString($namespace, $author, $source);
    }

    /**
     * Extra notice info for atom entries
     *
     * Clients use some extra notice info in the atom stream.
     * This gives it to them.
     *
     * @param User $cur Current user
     *
     * @return array representation of <statusnet:notice_info> element
     */

    function noticeInfo($cur)
    {
        // local notice ID (useful to clients for ordering)

        $noticeInfoAttr = array('local_id' => $this->id);

        // notice source

        $ns = $this->getSource();

        if (!empty($ns)) {
            $noticeInfoAttr['source'] =  $ns->code;
            if (!empty($ns->url)) {
                $noticeInfoAttr['source_link'] = $ns->url;
                if (!empty($ns->name)) {
                    $noticeInfoAttr['source'] =  '<a href="'
                        . htmlspecialchars($ns->url)
                        . '" rel="nofollow">'
                        . htmlspecialchars($ns->name)
                        . '</a>';
                }
            }
        }

        // favorite and repeated

        if (!empty($cur)) {
            $noticeInfoAttr['favorite'] = ($cur->hasFave($this)) ? "true" : "false";
            $cp = $cur->getProfile();
            $noticeInfoAttr['repeated'] = ($cp->hasRepeated($this->id)) ? "true" : "false";
        }

        if (!empty($this->repeat_of)) {
            $noticeInfoAttr['repeat_of'] = $this->repeat_of;
        }

        return array('statusnet:notice_info', $noticeInfoAttr, null);
    }

    /**
     * Returns an XML string fragment with a reference to a notice as an
     * Activity Streams noun object with the given element type.
     *
     * Assumes that 'activity' namespace has been previously defined.
     *
     * @param string $element one of 'subject', 'object', 'target'
     * @return string
     */

    function asActivityNoun($element)
    {
        $noun = ActivityObject::fromNotice($this);
        return $noun->asString('activity:' . $element);
    }

    function bestUrl()
    {
        if (!empty($this->url)) {
            return $this->url;
        } else if (!empty($this->uri) && preg_match('/^https?:/', $this->uri)) {
            return $this->uri;
        } else {
            return common_local_url('shownotice',
                                    array('notice' => $this->id));
        }
    }


    /**
     * Determine which notice, if any, a new notice is in reply to.
     *
     * For conversation tracking, we try to see where this notice fits
     * in the tree. Rough algorithm is:
     *
     * if (reply_to is set and valid) {
     *     return reply_to;
     * } else if ((source not API or Web) and (content starts with "T NAME" or "@name ")) {
     *     return ID of last notice by initial @name in content;
     * }
     *
     * Note that all @nickname instances will still be used to save "reply" records,
     * so the notice shows up in the mentioned users' "replies" tab.
     *
     * @param integer $reply_to   ID passed in by Web or API
     * @param integer $profile_id ID of author
     * @param string  $source     Source tag, like 'web' or 'gwibber'
     * @param string  $content    Final notice content
     *
     * @return integer ID of replied-to notice, or null for not a reply.
     */

    static function getReplyTo($reply_to, $profile_id, $source, $content)
    {
        static $lb = array('xmpp', 'mail', 'sms', 'omb');

        // If $reply_to is specified, we check that it exists, and then
        // return it if it does

        if (!empty($reply_to)) {
            $reply_notice = Notice::staticGet('id', $reply_to);
            if (!empty($reply_notice)) {
                return $reply_notice;
            }
        }

        // If it's not a "low bandwidth" source (one where you can't set
        // a reply_to argument), we return. This is mostly web and API
        // clients.

        if (!in_array($source, $lb)) {
            return null;
        }

        // Is there an initial @ or T?

        if (preg_match('/^T ([A-Z0-9]{1,64}) /', $content, $match) ||
            preg_match('/^@([a-z0-9]{1,64})\s+/', $content, $match)) {
            $nickname = common_canonical_nickname($match[1]);
        } else {
            return null;
        }

        // Figure out who that is.

        $sender = Profile::staticGet('id', $profile_id);
        if (empty($sender)) {
            return null;
        }

        $recipient = common_relative_profile($sender, $nickname, common_sql_now());

        if (empty($recipient)) {
            return null;
        }

        // Get their last notice

        $last = $recipient->getCurrentNotice();

        if (!empty($last)) {
            return $last;
        }

        return null;
    }

    static function maxContent()
    {
        $contentlimit = common_config('notice', 'contentlimit');
        // null => use global limit (distinct from 0!)
        if (is_null($contentlimit)) {
            $contentlimit = common_config('site', 'textlimit');
        }
        return $contentlimit;
    }

    static function contentTooLong($content)
    {
        $contentlimit = self::maxContent();
        return ($contentlimit > 0 && !empty($content) && (mb_strlen($content) > $contentlimit));
    }

    function getLocation()
    {
        $location = null;

        if (!empty($this->location_id) && !empty($this->location_ns)) {
            $location = Location::fromId($this->location_id, $this->location_ns);
        }

        if (is_null($location)) { // no ID, or Location::fromId() failed
            if (!empty($this->lat) && !empty($this->lon)) {
                $location = Location::fromLatLon($this->lat, $this->lon);
            }
        }

        return $location;
    }

    /**
     * Convenience function for posting a repeat of an existing message.
     *
     * @param int $repeater_id: profile ID of user doing the repeat
     * @param string $source: posting source key, eg 'web', 'api', etc
     * @return Notice
     *
     * @throws Exception on failure or permission problems
     */
    function repeat($repeater_id, $source)
    {
        $author = Profile::staticGet('id', $this->profile_id);

        // TRANS: Message used to repeat a notice. RT is the abbreviation of 'retweet'.
        // TRANS: %1$s is the repeated user's name, %2$s is the repeated notice.
        $content = sprintf(_('RT @%1$s %2$s'),
                           $author->nickname,
                           $this->content);

        $maxlen = common_config('site', 'textlimit');
        if ($maxlen > 0 && mb_strlen($content) > $maxlen) {
            // Web interface and current Twitter API clients will
            // pull the original notice's text, but some older
            // clients and RSS/Atom feeds will see this trimmed text.
            //
            // Unfortunately this is likely to lose tags or URLs
            // at the end of long notices.
            $content = mb_substr($content, 0, $maxlen - 4) . ' ...';
        }

        // Scope is same as this one's

        return self::saveNew($repeater_id,
                             $content,
                             $source,
                             array('repeat_of' => $this->id,
                                   'scope' => $this->scope));
    }

    // These are supposed to be in chron order!

    function repeatStream($limit=100)
    {
        $cache = Cache::instance();

        if (empty($cache)) {
            $ids = $this->_repeatStreamDirect($limit);
        } else {
            $idstr = $cache->get(Cache::key('notice:repeats:'.$this->id));
            if ($idstr !== false) {
                $ids = explode(',', $idstr);
            } else {
                $ids = $this->_repeatStreamDirect(100);
                $cache->set(Cache::key('notice:repeats:'.$this->id), implode(',', $ids));
            }
            if ($limit < 100) {
                // We do a max of 100, so slice down to limit
                $ids = array_slice($ids, 0, $limit);
            }
        }

        return NoticeStream::getStreamByIds($ids);
    }

    function _repeatStreamDirect($limit)
    {
        $notice = new Notice();

        $notice->selectAdd(); // clears it
        $notice->selectAdd('id');

        $notice->repeat_of = $this->id;

        $notice->orderBy('created, id'); // NB: asc!

        if (!is_null($limit)) {
            $notice->limit(0, $limit);
        }

        $ids = array();

        if ($notice->find()) {
            while ($notice->fetch()) {
                $ids[] = $notice->id;
            }
        }

        $notice->free();
        $notice = NULL;

        return $ids;
    }

    function locationOptions($lat, $lon, $location_id, $location_ns, $profile = null)
    {
        $options = array();

        if (!empty($location_id) && !empty($location_ns)) {
            $options['location_id'] = $location_id;
            $options['location_ns'] = $location_ns;

            $location = Location::fromId($location_id, $location_ns);

            if (!empty($location)) {
                $options['lat'] = $location->lat;
                $options['lon'] = $location->lon;
            }

        } else if (!empty($lat) && !empty($lon)) {
            $options['lat'] = $lat;
            $options['lon'] = $lon;

            $location = Location::fromLatLon($lat, $lon);

            if (!empty($location)) {
                $options['location_id'] = $location->location_id;
                $options['location_ns'] = $location->location_ns;
            }
        } else if (!empty($profile)) {
            if (isset($profile->lat) && isset($profile->lon)) {
                $options['lat'] = $profile->lat;
                $options['lon'] = $profile->lon;
            }

            if (isset($profile->location_id) && isset($profile->location_ns)) {
                $options['location_id'] = $profile->location_id;
                $options['location_ns'] = $profile->location_ns;
            }
        }

        return $options;
    }

    function clearReplies()
    {
        $replyNotice = new Notice();
        $replyNotice->reply_to = $this->id;

        //Null any notices that are replies to this notice

        if ($replyNotice->find()) {
            while ($replyNotice->fetch()) {
                $orig = clone($replyNotice);
                $replyNotice->reply_to = null;
                $replyNotice->update($orig);
            }
        }

        // Reply records

        $reply = new Reply();
        $reply->notice_id = $this->id;

        if ($reply->find()) {
            while($reply->fetch()) {
                self::blow('reply:stream:%d', $reply->profile_id);
                $reply->delete();
            }
        }

        $reply->free();
    }

    function clearFiles()
    {
        $f2p = new File_to_post();

        $f2p->post_id = $this->id;

        if ($f2p->find()) {
            while ($f2p->fetch()) {
                $f2p->delete();
            }
        }
        // FIXME: decide whether to delete File objects
        // ...and related (actual) files
    }

    function clearRepeats()
    {
        $repeatNotice = new Notice();
        $repeatNotice->repeat_of = $this->id;

        //Null any notices that are repeats of this notice

        if ($repeatNotice->find()) {
            while ($repeatNotice->fetch()) {
                $orig = clone($repeatNotice);
                $repeatNotice->repeat_of = null;
                $repeatNotice->update($orig);
            }
        }
    }

    function clearFaves()
    {
        $fave = new Fave();
        $fave->notice_id = $this->id;

        if ($fave->find()) {
            while ($fave->fetch()) {
                self::blow('fave:ids_by_user_own:%d', $fave->user_id);
                self::blow('fave:ids_by_user_own:%d;last', $fave->user_id);
                self::blow('fave:ids_by_user:%d', $fave->user_id);
                self::blow('fave:ids_by_user:%d;last', $fave->user_id);
                $fave->delete();
            }
        }

        $fave->free();
    }

    function clearTags()
    {
        $tag = new Notice_tag();
        $tag->notice_id = $this->id;

        if ($tag->find()) {
            while ($tag->fetch()) {
                self::blow('profile:notice_ids_tagged:%d:%s', $this->profile_id, Cache::keyize($tag->tag));
                self::blow('profile:notice_ids_tagged:%d:%s;last', $this->profile_id, Cache::keyize($tag->tag));
                self::blow('notice_tag:notice_ids:%s', Cache::keyize($tag->tag));
                self::blow('notice_tag:notice_ids:%s;last', Cache::keyize($tag->tag));
                $tag->delete();
            }
        }

        $tag->free();
    }

    function clearGroupInboxes()
    {
        $gi = new Group_inbox();

        $gi->notice_id = $this->id;

        if ($gi->find()) {
            while ($gi->fetch()) {
                self::blow('user_group:notice_ids:%d', $gi->group_id);
                $gi->delete();
            }
        }

        $gi->free();
    }

    function distribute()
    {
        // We always insert for the author so they don't
        // have to wait
        Event::handle('StartNoticeDistribute', array($this));

        $user = User::staticGet('id', $this->profile_id);
        if (!empty($user)) {
            Inbox::insertNotice($user->id, $this->id);
        }

        if (common_config('queue', 'inboxes')) {
            // If there's a failure, we want to _force_
            // distribution at this point.
            try {
                $qm = QueueManager::get();
                $qm->enqueue($this, 'distrib');
            } catch (Exception $e) {
                // If the exception isn't transient, this
                // may throw more exceptions as DQH does
                // its own enqueueing. So, we ignore them!
                try {
                    $handler = new DistribQueueHandler();
                    $handler->handle($this);
                } catch (Exception $e) {
                    common_log(LOG_ERR, "emergency redistribution resulted in " . $e->getMessage());
                }
                // Re-throw so somebody smarter can handle it.
                throw $e;
            }
        } else {
            $handler = new DistribQueueHandler();
            $handler->handle($this);
        }
    }

    function insert()
    {
        $result = parent::insert();

        if ($result) {
            // Profile::hasRepeated() abuses pkeyGet(), so we
            // have to clear manually
            if (!empty($this->repeat_of)) {
                $c = self::memcache();
                if (!empty($c)) {
                    $ck = self::multicacheKey('Notice',
                                              array('profile_id' => $this->profile_id,
                                                    'repeat_of' => $this->repeat_of));
                    $c->delete($ck);
                }
            }
        }

        return $result;
    }

    /**
     * Get the source of the notice
     *
     * @return Notice_source $ns A notice source object. 'code' is the only attribute
     *                           guaranteed to be populated.
     */
    function getSource()
    {
        $ns = new Notice_source();
        if (!empty($this->source)) {
            switch ($this->source) {
            case 'web':
            case 'xmpp':
            case 'mail':
            case 'omb':
            case 'system':
            case 'api':
                $ns->code = $this->source;
                break;
            default:
                $ns = Notice_source::staticGet($this->source);
                if (!$ns) {
                    $ns = new Notice_source();
                    $ns->code = $this->source;
                    $app = Oauth_application::staticGet('name', $this->source);
                    if ($app) {
                        $ns->name = $app->name;
                        $ns->url  = $app->source_url;
                    }
                }
                break;
            }
        }
        return $ns;
    }

    /**
     * Determine whether the notice was locally created
     *
     * @return boolean locality
     */

    public function isLocal()
    {
        return ($this->is_local == Notice::LOCAL_PUBLIC ||
                $this->is_local == Notice::LOCAL_NONPUBLIC);
    }

    /**
     * Get the list of hash tags saved with this notice.
     *
     * @return array of strings
     */
    public function getTags()
    {
        $tags = array();

        $keypart = sprintf('notice:tags:%d', $this->id);

        $tagstr = self::cacheGet($keypart);

        if ($tagstr !== false) {
            $tags = explode(',', $tagstr);
        } else {
            $tag = new Notice_tag();
            $tag->notice_id = $this->id;
            if ($tag->find()) {
                while ($tag->fetch()) {
                    $tags[] = $tag->tag;
                }
            }
            self::cacheSet($keypart, implode(',', $tags));
        }

        return $tags;
    }

    static private function utcDate($dt)
    {
        $dateStr = date('d F Y H:i:s', strtotime($dt));
        $d = new DateTime($dateStr, new DateTimeZone('UTC'));
        return $d->format(DATE_W3C);
    }

    /**
     * Look up the creation timestamp for a given notice ID, even
     * if it's been deleted.
     *
     * @param int $id
     * @return mixed string recorded creation timestamp, or false if can't be found
     */
    public static function getAsTimestamp($id)
    {
        if (!$id) {
            return false;
        }

        $notice = Notice::staticGet('id', $id);
        if ($notice) {
            return $notice->created;
        }

        $deleted = Deleted_notice::staticGet('id', $id);
        if ($deleted) {
            return $deleted->created;
        }

        return false;
    }

    /**
     * Build an SQL 'where' fragment for timestamp-based sorting from a since_id
     * parameter, matching notices posted after the given one (exclusive).
     *
     * If the referenced notice can't be found, will return false.
     *
     * @param int $id
     * @param string $idField
     * @param string $createdField
     * @return mixed string or false if no match
     */
    public static function whereSinceId($id, $idField='id', $createdField='created')
    {
        $since = Notice::getAsTimestamp($id);
        if ($since) {
            return sprintf("($createdField = '%s' and $idField > %d) or ($createdField > '%s')", $since, $id, $since);
        }
        return false;
    }

    /**
     * Build an SQL 'where' fragment for timestamp-based sorting from a since_id
     * parameter, matching notices posted after the given one (exclusive), and
     * if necessary add it to the data object's query.
     *
     * @param DB_DataObject $obj
     * @param int $id
     * @param string $idField
     * @param string $createdField
     * @return mixed string or false if no match
     */
    public static function addWhereSinceId(DB_DataObject $obj, $id, $idField='id', $createdField='created')
    {
        $since = self::whereSinceId($id, $idField, $createdField);
        if ($since) {
            $obj->whereAdd($since);
        }
    }

    /**
     * Build an SQL 'where' fragment for timestamp-based sorting from a max_id
     * parameter, matching notices posted before the given one (inclusive).
     *
     * If the referenced notice can't be found, will return false.
     *
     * @param int $id
     * @param string $idField
     * @param string $createdField
     * @return mixed string or false if no match
     */
    public static function whereMaxId($id, $idField='id', $createdField='created')
    {
        $max = Notice::getAsTimestamp($id);
        if ($max) {
            return sprintf("($createdField < '%s') or ($createdField = '%s' and $idField <= %d)", $max, $max, $id);
        }
        return false;
    }

    /**
     * Build an SQL 'where' fragment for timestamp-based sorting from a max_id
     * parameter, matching notices posted before the given one (inclusive), and
     * if necessary add it to the data object's query.
     *
     * @param DB_DataObject $obj
     * @param int $id
     * @param string $idField
     * @param string $createdField
     * @return mixed string or false if no match
     */
    public static function addWhereMaxId(DB_DataObject $obj, $id, $idField='id', $createdField='created')
    {
        $max = self::whereMaxId($id, $idField, $createdField);
        if ($max) {
            $obj->whereAdd($max);
        }
    }

    function isPublic()
    {
        if (common_config('public', 'localonly')) {
            return ($this->is_local == Notice::LOCAL_PUBLIC);
        } else {
            return (($this->is_local != Notice::LOCAL_NONPUBLIC) &&
                    ($this->is_local != Notice::GATEWAY));
        }
    }

    /**
     * Check that the given profile is allowed to read, respond to, or otherwise
     * act on this notice.
     * 
     * The $scope member is a bitmask of scopes, representing a logical AND of the
     * scope requirement. So, 0x03 (Notice::ADDRESSEE_SCOPE | Notice::SITE_SCOPE) means
     * "only visible to people who are mentioned in the notice AND are users on this site."
     * Users on the site who are not mentioned in the notice will not be able to see the
     * notice.
     *
     * @param Profile $profile The profile to check; pass null to check for public/unauthenticated users.
     *
     * @return boolean whether the profile is in the notice's scope
     */
    function inScope($profile)
    {
        $keypart = sprintf('notice:in-scope-for:%d:%d', $this->id, $profile->id);

        $result = self::cacheGet($keypart);

        if ($result === false) {
            $bResult = $this->_inScope($profile);
            $result = ($bResult) ? 1 : 0;
            self::cacheSet($keypart, $result, 0, 300);
        }

        return ($result == 1) ? true : false;
    }

    protected function _inScope($profile)
    {
        // If there's no scope, anyone (even anon) is in scope.

        if ($this->scope == 0) {
            return true;
        }

        // If there's scope, anon cannot be in scope

        if (empty($profile)) {
            return false;
        }

        // Author is always in scope

        if ($this->profile_id == $profile->id) {
            return true;
        }

        // Only for users on this site

        if ($this->scope & Notice::SITE_SCOPE) {
            $user = $profile->getUser();
            if (empty($user)) {
                return false;
            }
        }

        // Only for users mentioned in the notice

        if ($this->scope & Notice::ADDRESSEE_SCOPE) {

            // XXX: just query for the single reply

            $replies = $this->getReplies();

            if (!in_array($profile->id, $replies)) {
                return false;
            }
        }

        // Only for members of the given group

        if ($this->scope & Notice::GROUP_SCOPE) {

            // XXX: just query for the single membership

            $groups = $this->getGroups();

            $foundOne = false;

            foreach ($groups as $group) {
                if ($profile->isMember($group)) {
                    $foundOne = true;
                    break;
                }
            }

            if (!$foundOne) {
                return false;
            }
        }

        // Only for followers of the author

        if ($this->scope & Notice::FOLLOWER_SCOPE) {
            $author = $this->getProfile();
            if (!Subscription::exists($profile, $author)) {
                return false;
            }
        }

        return true;
    }

    static function groupsFromText($text, $profile)
    {
        $groups = array();

        /* extract all !group */
        $count = preg_match_all('/(?:^|\s)!(' . Nickname::DISPLAY_FMT . ')/',
                                strtolower($text),
                                $match);

        if (!$count) {
            return $groups;
        }

        foreach (array_unique($match[1]) as $nickname) {
            $group = User_group::getForNickname($nickname, $profile);
            if (!empty($group) && $profile->isMember($group)) {
                $groups[] = $group->id;
            }
        }

        return $groups;
    }
}