class.thread.php

            $json[$att->file->getKey()] = array(
                'download_url' => $att->file->getDownloadUrl(),
                'filename' => $att->getFilename(),
            );
        }

        return $json;
    }

    function getAttachmentsLinks($file='attachment.php', $target='_blank', $separator=' ') {
        // TODO: Move this to the respective UI templates

        $str='';
        foreach ($this->attachments as $att ) {
            if ($att->inline) continue;
            $size = '';
            if ($att->file->size)
                $size=sprintf('<em>(%s)</em>', Format::file_size($att->file->size));

            $str .= sprintf(
                '<a class="Icon file no-pjax" href="%s" target="%s">%s</a>%s&nbsp;%s',
                $att->file->getDownloadUrl(), $target,
                Format::htmlchars($att->file->name), $size, $separator);
        }

        return $str;
    }

    /* save email info
     * TODO: Refactor it to include outgoing emails on responses.
     */

    function saveEmailInfo($vars) {

        // Don't save empty message ID
        if (!$vars || !$vars['mid'])
            return 0;

        $this->ht['email_mid'] = $vars['mid'];

        $header = false;
        if (isset($vars['header']))
            $header = $vars['header'];
        self::logEmailHeaders($this->getId(), $vars['mid'], $header);
    }

    /* static */
    function logEmailHeaders($id, $mid, $header=false) {

        if (!$id || !$mid)
            return false;

        $this->email_info = new ThreadEntryEmailInfo(array(
            'thread_entry_id' => $id,
            'mid' => $mid,
        ));

        if ($header)
            $this->email_info->headers = trim($header);

        return $this->email_info->save();
    }

    function getActivity() {
        return new ThreadActivity('', '');
    }

    /* variables */

    function __toString() {
        return (string) $this->getBody();
    }

    // TemplateVariable interface
    function asVar() {
        return (string) $this->getBody()->display('email');
    }

    function getVar($tag) {
        switch(strtolower($tag)) {
            case 'create_date':
                return new FormattedDate($this->getCreateDate());
            case 'update_date':
                return new FormattedDate($this->getUpdateDate());
            case 'files':
                throw new OOBContent(OOBContent::FILES, $this->attachments->all());
        }
    }

    static function getVarScope() {
        return array(
          'files' => __('Attached files'),
          'body' => __('Message body'),
          'create_date' => array(
              'class' => 'FormattedDate', 'desc' => __('Date created'),
          ),
          'ip_address' => __('IP address of remote user, for web submissions'),
          'poster' => __('Submitter of the thread item'),
          'staff' => array(
            'class' => 'Staff', 'desc' => __('Agent posting the note or response'),
          ),
          'title' => __('Subject, if any'),
          'user' => array(
            'class' => 'User', 'desc' => __('User posting the message'),
          ),
        );
    }

    /**
     * Parameters:
     * mailinfo (hash<String>) email header information. Must include keys
     *  - "mid" => Message-Id header of incoming mail
     *  - "in-reply-to" => Message-Id the email is a direct response to
     *  - "references" => List of Message-Id's the email is in response
     *  - "subject" => Find external ticket number in the subject line
     *
     *  seen (by-ref:bool) a flag that will be set if the message-id was
     *      positively found, indicating that the message-id has been
     *      previously seen. This is useful if no thread-id is associated
     *      with the email (if it was rejected for instance).
     */
    function lookupByEmailHeaders(&$mailinfo, &$seen=false) {
        // Search for messages using the References header, then the
        // in-reply-to header
        if ($mailinfo['mid'] &&
                ($entry = ThreadEntry::objects()
                 ->filter(array('email_info__mid' => $mailinfo['mid']))
                 ->order_by(false)
                 ->first()
                 )
         ) {
            $seen = true;
            return $entry;
        }

        $possibles = array();
        foreach (array('mid', 'in-reply-to', 'references') as $header) {
            $matches = array();
            if (!isset($mailinfo[$header]) || !$mailinfo[$header])
                continue;
            // Header may have multiple entries (usually separated by
            // spaces ( )
            elseif (!preg_match_all('/<([^>@]+@[^>]+)>/', $mailinfo[$header],
                        $matches))
                continue;

            // The References header will have the most recent message-id
            // (parent) on the far right.
            // @see rfc 1036, section 2.2.5
            // @see http://www.jwz.org/doc/threading.html
            $possibles = array_merge($possibles, array_reverse($matches[1]));
        }

        // Add the message id if it is embedded in the body
        $match = array();
        if (preg_match('`(?:class="mid-|Ref-Mid: )([^"\s]*)(?:$|")`',
                (string) $mailinfo['message'], $match)
            && !in_array($match[1], $possibles)
        ) {
            $possibles[] = $match[1];
        }

        $thread = null;
        foreach ($possibles as $mid) {
            // Attempt to detect the ticket and user ids from the
            // message-id header. If the message originated from
            // osTicket, the Mailer class can break it apart. If it came
            // from this help desk, the 'loopback' property will be set
            // to true.
            $mid_info = Mailer::decodeMessageId($mid);
            if (!$mid_info || !$mid_info['loopback'])
                continue;
            if (isset($mid_info['uid'])
                && @$mid_info['entryId']
                && ($t = ThreadEntry::lookup($mid_info['entryId']))
                && ($t->thread_id == $mid_info['threadId'])
            ) {
                if (@$mid_info['userId']) {
                    $mailinfo['userId'] = $mid_info['userId'];
                }
                elseif (@$mid_info['staffId']) {
                    $mailinfo['staffId'] = $mid_info['staffId'];
                }

                // Capture the user type
                if (@$mid_info['userClass'])
                    $mailinfo['userClass'] = $mid_info['userClass'];


                // ThreadEntry was positively identified
                return $t;
            }
        }
        // Passive threading - listen mode
        if (count($possibles)
                && ($entry = ThreadEntry::objects()
                    ->filter(array('email_info__mid__in' => array_map(
                        function ($a) { return "<$a>"; },
                    $possibles)))
                    ->first()
                )
         ) {
            $mailinfo['passive'] = true;
            return $entry;
        }

        // Search for ticket by the [#123456] in the subject line
        // This is the last resort -  emails must match to avoid message
        // injection by third-party.
        $subject = $mailinfo['subject'];
        $match = array();
        if ($subject
                && $mailinfo['email']
                // Required `#` followed by one or more of
                //      punctuation (-) then letters, numbers, and symbols
                // (Try not to match closing punctuation (`]`) in [#12345])
                && preg_match("/#((\p{P}*[^\p{C}\p{Z}\p{P}]+)+)/u", $subject, $match)
                //Lookup by ticket number
                && ($ticket = Ticket::lookupByNumber($match[1]))
                //Lookup the user using the email address
                && ($user = User::lookup(array('emails__address' => $mailinfo['email'])))) {
            //We have a valid ticket and user
            if ($ticket->getUserId() == $user->getId() //owner
                    ||  ($c = Collaborator::lookup( // check if collaborator
                            array('user_id' => $user->getId(),
                                  'thread_id' => $ticket->getThreadId())))) {

                $mailinfo['userId'] = $user->getId();
                return $ticket->getLastMessage();
            }
        }

        return null;
    }

    /**
     * Find a thread entry from a message-id created from the
     * ::asMessageId() method.
     *
     * *DEPRECATED* use Mailer::decodeMessageId() instead
     */
    function lookupByRefMessageId($mid, $from) {
        global $ost;

        $mid = trim($mid, '<>');
        list($ver, $ids, $mails) = explode('$', $mid, 3);

        // Current version is <null>
        if ($ver !== '')
            return false;

        $ids = @unpack('Vthread', base64_decode($ids));
        if (!$ids || !$ids['thread'])
            return false;

        $entry = ThreadEntry::lookup($ids['thread']);
        if (!$entry)
            return false;

        // Compute the value to be compared from $mails (which used to be in
        // ThreadEntry::asMessageId() (#nolint)
        $domain = md5($ost->getConfig()->getURL());
        $ticket = $entry->getThread()->getObject();
        if (!$ticket instanceof Ticket)
            return false;

        $check = sprintf('%s@%s',
            substr(md5($from . $ticket->getNumber() . $ticket->getId()), -10),
            substr($domain, -10)
        );

        if ($check != $mails)
            return false;

        return $entry;
    }

    //new entry ... we're trusting the caller to check validity of the data.
    static function create($vars=false) {
        global $cfg;

        assert(is_array($vars));

        //Must have...
        if (!$vars['threadId'] || !$vars['type'])
            return false;


        if (!$vars['body'] instanceof ThreadEntryBody) {
            if ($cfg->isRichTextEnabled())
                $vars['body'] = new HtmlThreadEntryBody($vars['body']);
            else
                $vars['body'] = new TextThreadEntryBody($vars['body']);
        }

        if (!($body = $vars['body']->getClean()))
            $body = '-'; //Special tag used to signify empty message as stored.

        $poster = $vars['poster'];
        if ($poster && is_object($poster))
            $poster = (string) $poster;

        $entry = new static(array(
            'created' => SqlFunction::NOW(),
            'type' => $vars['type'],
            'thread_id' => $vars['threadId'],
            'title' => Format::sanitize($vars['title'], true),
            'format' => $vars['body']->getType(),
            'staff_id' => $vars['staffId'],
            'user_id' => $vars['userId'],
            'poster' => $poster,
            'source' => $vars['source'],
            'flags' => $vars['flags'] ?: 0,
        ));

        if ($entry->format == 'html')
            // The current codebase properly balances html
            $entry->flags |= self::FLAG_BALANCED;

        // Flag system messages
        if (!($vars['staffId'] || $vars['userId']))
            $entry->flags |= self::FLAG_SYSTEM;

        if (isset($vars['pid']))
            $entry->pid = $vars['pid'];
        // Check if 'reply_to' is in the $vars as the previous ThreadEntry
        // instance. If the body of the previous message is found in the new
        // body, strip it out.
        elseif (isset($vars['reply_to'])
                && $vars['reply_to'] instanceof ThreadEntry)
            $entry->pid = $vars['reply_to']->getId();

        if ($vars['ip_address'])
            $entry->ip_address = $vars['ip_address'];

        /************* ATTACHMENTS *****************/
        // Drop stripped email inline images
        if ($vars['attachments']) {
            foreach ($vars['body']->getStrippedImages() as $cid) {
                foreach ($vars['attachments'] as $i=>$a) {
                    if (@$a['cid'] && $a['cid'] == $cid) {
                        // Inline referenced attachment was stripped
                        unset($vars['attachments'][$i]);
                    }
                }
            }
        }

        // Handle extracted embedded images (<img src="data:base64,..." />).
        // The extraction has already been performed in the ThreadEntryBody
        // class. Here they should simply be added to the attachments list
        if ($atts = $vars['body']->getEmbeddedHtmlImages()) {
            if (!is_array($vars['attachments']))
                $vars['attachments'] = array();
            foreach ($atts as $info) {
                $vars['attachments'][] = $info;
            }
        }

        $attached_files = array();
        foreach (array(
            // Web uploads and canned attachments
            $vars['files'], $vars['cannedattachments'],
            // Emailed or API attachments
            $vars['attachments'],
            // Inline images (attached to the draft)
            Draft::getAttachmentIds($body),
        ) as $files
        ) {
            if (is_array($files)) {
                // Detect *inline* email attachments
                foreach ($files as $i=>$a) {
                    if (isset($a['cid']) && $a['cid']
                            && strpos($body, 'cid:'.$a['cid']) !== false)
                        $files[$i]['inline'] = true;
                }
                foreach ($entry->normalizeFileInfo($files) as $F) {
                    // Deduplicate on the `key` attribute. The key is
                    // necessary for the CID rewrite below
                    $attached_files[$F['key']] = $F;
                }
            }
        }

        // Change <img src="cid:"> inside the message to point to a unique
        // hash-code for the attachment. Since the content-id will be
        // discarded, only the unique hash-code (key) will be available to
        // retrieve the image later
        foreach ($attached_files as $key => $a) {
            if (isset($a['cid']) && $a['cid']) {
                $body = preg_replace('/src=("|\'|\b)(?:cid:)?'
                    . preg_quote($a['cid'], '/').'\1/i',
                    'src="cid:'.$key.'"', $body);
            }
        }

        // Set body here after it was rewritten to capture the stored file
        // keys (above)
        $entry->body = $body;

        if (!$entry->save())
            return false;

        // Associate the attached files with this new entry
        $entry->createAttachments($attached_files);

        // Save mail message id, if available
        $entry->saveEmailInfo($vars);

        Signal::send('threadentry.created', $entry);

        return $entry;
    }

    static function add($vars, &$errors=array()) {
        return self::create($vars);
    }

    // Extensible thread entry actions ------------------------
    /**
     * getActions
     *
     * Retrieve a list of possible actions. This list is shown to the agent
     * via drop-down list at the top-right of the thread entry when rendered
     * in the UI.
     */
    function getActions() {
        if (!isset($this->_actions)) {
            $this->_actions = array();

            foreach (self::$action_registry as $group=>$list) {
                $T = array();
                $this->_actions[__($group)] = &$T;
                foreach ($list as $id=>$action) {
                    $A = new $action($this);
                    if ($A->isVisible()) {
                        $T[$id] = $A;
                    }
                }
                unset($T);
            }
        }
        return $this->_actions;
    }

    function hasActions() {
        foreach ($this->getActions() as $group => $list) {
            if (count($list))
                return true;
        }
        return false;
    }

    function triggerAction($name) {
        foreach ($this->getActions() as $group=>$list) {
            foreach ($list as $id=>$action) {
                if (0 === strcasecmp($id, $name)) {
                    if (!$action->isEnabled())
                        return false;

                    $action->trigger();
                    return true;
                }
            }
        }
        return false;
    }

    static $action_registry = array();

    static function registerAction($group, $action) {
        if (!isset(self::$action_registry[$group]))
            self::$action_registry[$group] = array();

        self::$action_registry[$group][$action::getId()] = $action;
    }

    static function getPermissions() {
        return self::$perms;
    }
}

RolePermission::register(/* @trans */ 'Tickets', ThreadEntry::getPermissions());

class ThreadEvent extends VerySimpleModel {
    static $meta = array(
        'table' => THREAD_EVENT_TABLE,
        'pk' => array('id'),
        'joins' => array(
            // Originator of activity
            'agent' => array(
                'constraint' => array(
                    'uid' => 'Staff.staff_id',
                ),
                'null' => true,
            ),
            // Agent assignee
            'staff' => array(
                'constraint' => array(
                    'staff_id' => 'Staff.staff_id',
                ),
                'null' => true,
            ),
            'team' => array(
                'constraint' => array(
                    'team_id' => 'Team.team_id',
                ),
                'null' => true,
            ),
            'thread' => array(
                'constraint' => array('thread_id' => 'Thread.id'),
            ),
            'user' => array(
                'constraint' => array(
                    'uid' => 'User.id',
                ),
                'null' => true,
            ),
            'dept' => array(
                'constraint' => array(
                    'dept_id' => 'Dept.id',
                ),
                'null' => true,
            ),
        ),
    );

    // Valid events for database storage
    const ASSIGNED  = 'assigned';
    const CLOSED    = 'closed';
    const CREATED   = 'created';
    const COLLAB    = 'collab';
    const EDITED    = 'edited';
    const ERROR     = 'error';
    const OVERDUE   = 'overdue';
    const REOPENED  = 'reopened';
    const STATUS    = 'status';
    const TRANSFERRED = 'transferred';
    const VIEWED    = 'viewed';

    const MODE_STAFF = 1;
    const MODE_CLIENT = 2;

    var $_data;

    function getAvatar($size=null) {
        if ($this->uid && $this->uid_type == 'S')
            return $this->agent ? $this->agent->getAvatar($size) : '';
        if ($this->uid && $this->uid_type == 'U')
            return $this->user ? $this->user->getAvatar($size) : '';
    }

    function getUserName() {
        if ($this->uid && $this->uid_type == 'S')
            return $this->agent ? $this->agent->getName() : $this->username;
        if ($this->uid && $this->uid_type == 'U')
            return $this->user ? $this->user->getName() : $this->username;
        return $this->username;
    }

    function getIcon() {
        $icons = array(
            'assigned'  => 'hand-right',
            'collab'    => 'group',
            'created'   => 'magic',
            'overdue'   => 'time',
            'transferred' => 'share-alt',
            'edited'    => 'pencil',
            'closed'    => 'thumbs-up-alt',
            'reopened'  => 'rotate-right',
            'resent'    => 'reply-all icon-flip-horizontal',
        );
        return @$icons[$this->state] ?: 'chevron-sign-right';
    }

    function getDescription($mode=self::MODE_STAFF) {
        // Abstract description
        return $this->template(sprintf(
            __('%s by {somebody} {timestamp}'),
            $this->state
        ));
    }

    function template($description) {
        global $thisstaff, $cfg;

        $self = $this;
        return preg_replace_callback('/\{(<(?P<type>([^>]+))>)?(?P<key>[^}.]+)(\.(?P<data>[^}]+))?\}/',
            function ($m) use ($self, $thisstaff, $cfg) {
                switch ($m['key']) {
                case 'assignees':
                    $assignees = array();
                    if ($S = $self->staff) {
                        $avatar = '';
                        if ($cfg->isAvatarsEnabled())
                            $avatar = $S->getAvatar();
                        $assignees[] =
                            $avatar.$S->getName();
                    }
                    if ($T = $self->team) {
                        $assignees[] = $T->getLocalName();
                    }
                    return implode('/', $assignees);
                case 'somebody':
                    $name = $self->getUserName();
                    if ($cfg->isAvatarsEnabled()
                            && ($avatar = $self->getAvatar()))
                        $name = $avatar.$name;
                    return $name;
                case 'timestamp':
                    $timeFormat = null;
                    if ($thisstaff
                            && !strcasecmp($thisstaff->datetime_format,
                                'relative')) {
                        $timeFormat = function ($timestamp) {
                            return Format::relativeTime(Misc::db2gmtime($timestamp));
                        };
                    }

                    return sprintf('<time %s datetime="%s"
                            data-toggle="tooltip" title="%s">%s</time>',
                        $timeFormat ? 'class="relative"' : '',
                        date(DateTime::W3C, Misc::db2gmtime($self->timestamp)),
                        Format::daydatetime($self->timestamp),
                        $timeFormat ? $timeFormat($self->timestamp) :
                        Format::datetime($self->timestamp)
                    );
                case 'agent':
                    $name = $self->agent->getName();
                    if ($cfg->isAvatarsEnabled()
                            && ($avatar = $self->getAvatar()))
                        $name = $avatar.$name;
                    return $name;
                case 'dept':
                    if ($dept = $self->getDept())
                        return $dept->getLocalName();
                    return __('None');
                case 'data':
                    $val = $self->getData($m['data']);
                    if (is_array($val))
                        list($val, $fallback) = $val;
                    if ($m['type'] && class_exists($m['type']))
                        $val = $m['type']::lookup($val);
                    if (!$val && $fallback)
                        $val = $fallback;
                    return Format::htmlchars((string) $val);
                }
                return $m[0];
            },
            $description
        );
    }

    function getDept() {
        return $this->dept;
    }

    function getData($key=false) {
        if (!isset($this->_data))
            $this->_data = JsonDataParser::decode($this->data);
        return ($key) ? @$this->_data[$key] : $this->_data;
    }

    function render($mode) {
        $inc = ($mode == self::MODE_STAFF) ? STAFFINC_DIR : CLIENTINC_DIR;
        $event = $this->getTypedEvent();
        include $inc . 'templates/thread-event.tmpl.php';
    }

    static function create($ht=false, $user=false) {
        $inst = new static($ht);
        $inst->timestamp = SqlFunction::NOW();

        global $thisstaff, $thisclient;
        $user = is_object($user) ? $user : $thisstaff ?: $thisclient;
        if ($user instanceof Staff) {
            $inst->uid_type = 'S';
            $inst->uid = $user->getId();
        }
        elseif ($user instanceof User) {
            $inst->uid_type = 'U';
            $inst->uid = $user->getId();
        }

        return $inst;
    }

    static function forTicket($ticket, $state, $user=false) {
        $inst = self::create(array(
            'staff_id' => $ticket->getStaffId(),
            'team_id' => $ticket->getTeamId(),
            'dept_id' => $ticket->getDeptId(),
            'topic_id' => $ticket->getTopicId(),
        ), $user);
        return $inst;
    }

    function getTypedEvent() {
        static $subclasses;

        if (!isset($subclasses)) {
            $parent = get_class($this);
            $subclasses = array();
            foreach (get_declared_classes() as $class) {
                if (is_subclass_of($class, $parent))
                    $subclasses[$class::$state] = $class;
            }
        }
        if (!($class = $subclasses[$this->state]))
            return $this;
        return new $class($this->ht);
    }
}

class ThreadEvents extends InstrumentedList {
    function annul($event) {
        $this->queryset
            ->filter(array('state' => $event))
            ->update(array('annulled' => 1));
    }

    /**
     * Add an event to the thread activity log.
     *
     * Parameters:
     * $object - Object to log activity for
     * $state - State name of the activity (one of 'created', 'edited',
     *      'deleted', 'closed', 'reopened', 'error', 'collab', 'resent',
     *      'assigned', 'transferred')
     * $data - (array?) Details about the state change
     * $user - (string|User|Staff) user triggering the state change
     * $annul - (state) a corresponding state change that is annulled by
     *      this event
     */
    function log($object, $state, $data=null, $user=null, $annul=null) {
        global $thisstaff, $thisclient;

        if ($object instanceof Ticket)
            // TODO: Use $object->createEvent() (nolint)
            $event = ThreadEvent::forTicket($object, $state, $user);
        else
            $event = ThreadEvent::create(false, $user);

        # Annul previous entries if requested (for instance, reopening a
        # ticket will annul an 'closed' entry). This will be useful to
        # easily prevent repeated statistics.
        if ($annul) {
            $this->annul($annul);
        }

        $username = $user;
        $user = is_object($user) ? $user : $thisclient ?: $thisstaff;
        if (!is_string($username)) {
            if ($user instanceof Staff) {
                $username = $user->getUserName();
            }
            // XXX: Use $user here
            elseif ($thisclient) {
                if ($thisclient->hasAccount)
                    $username = $thisclient->getAccount()->getUserName();
                if (!$username)
                    $username = $thisclient->getEmail();
            }
            else {
                # XXX: Security Violation ?
                $username = 'SYSTEM';
            }
        }
        $event->username = $username;
        $event->state = $state;

        if ($data) {
            if (is_array($data))
                $data = JsonDataEncoder::encode($data);
            if (!is_string($data))
                throw new InvalidArgumentException('Data must be string or array');
            $event->data = $data;
        }

        $this->add($event);

        // Save event immediately
        return $event->save();
    }
}

class AssignmentEvent extends ThreadEvent {
    static $icon = 'hand-right';
    static $state = 'assigned';

    function getDescription($mode=self::MODE_STAFF) {
        $data = $this->getData();
        switch (true) {
        case !is_array($data):
        default:
            $desc = __('Assignee changed by <b>{somebody}</b> to <strong>{assignees}</strong> {timestamp}');
            break;
        case isset($data['staff']):
            $desc = __('<b>{somebody}</b> assigned this to <strong>{<Staff>data.staff}</strong> {timestamp}');
            break;
        case isset($data['team']):
            $desc = __('<b>{somebody}</b> assigned this to <strong>{<Team>data.team}</strong> {timestamp}');
            break;
        case isset($data['claim']):
            $desc = __('<b>{somebody}</b> claimed this {timestamp}');
            break;
        }
        return $this->template($desc);
    }
}

class CloseEvent extends ThreadEvent {
    static $icon = 'thumbs-up-alt';
    static $state = 'closed';

    function getDescription($mode=self::MODE_STAFF) {
        if ($this->getData('status'))
            return $this->template(__('Closed by <b>{somebody}</b> with status of {<TicketStatus>data.status} {timestamp}'));
        else
            return $this->template(__('Closed by <b>{somebody}</b> {timestamp}'));
    }
}

class CollaboratorEvent extends ThreadEvent {
    static $icon = 'group';
    static $state = 'collab';

    function getDescription($mode=self::MODE_STAFF) {
        $data = $this->getData();
        switch (true) {
        case isset($data['org']):
            $desc = __('Collaborators for {<Organization>data.org} organization added');
            break;
        case isset($data['del']):
            $base = __('<b>{somebody}</b> removed <strong>%s</strong> from the collaborators {timestamp}');
            $collabs = array();
            $users = User::objects()->filter(array('id__in' => array_keys($data['del'])));
            foreach ($data['del'] as $id=>$c) {
                $U = false;
                foreach ($users as $user) {
                    if ($user->id == $id) {
                        $U = $user;
                        break;
                    }
                }
                $collabs[] = Format::htmlchars($U ? $U->getName() : @$c['name'] ?: $c);
            }
            $desc = sprintf($base, implode(', ', $collabs));
            break;
        case isset($data['add']):
            $base = __('<b>{somebody}</b> added <strong>%s</strong> as collaborators {timestamp}');
            $collabs = array();
            if ($data['add']) {
                $users = User::objects()->filter(array('id__in' => array_keys($data['add'])));
                foreach ($data['add'] as $id=>$c) {
                    $U = false;
                    foreach ($users as $user) {
                        if ($user->id == $id) {
                            $U = $user;
                            break;
                        }
                    }
                    $c = sprintf("%s %s",
                        Format::htmlchars($U ? $U->getName() : @$c['name'] ?: $c),
                        $c['src'] ? sprintf(__('via %s'
                            /* e.g. "Added collab "Me <me@company.me>" via Email (to)" */
                            ), $c['src']) : ''
                    );
                    $collabs[] = $c;
                }
            }
            $desc = $collabs
                ? sprintf($base, implode(', ', $collabs))
                : 'somebody';
            break;
        }
        return $this->template($desc);
    }
}

class CreationEvent extends ThreadEvent {
    static $icon = 'magic';
    static $state = 'created';

    function getDescription($mode=self::MODE_STAFF) {
        return $this->template(__('Created by <b>{somebody}</b> {timestamp}'));
    }
}

class EditEvent extends ThreadEvent {
    static $icon = 'pencil';
    static $state = 'edited';

    function getDescription($mode=self::MODE_STAFF) {
        $data = $this->getData();
        switch (true) {
        case isset($data['owner']):
            $desc = __('<b>{somebody}</b> changed ownership to {<User>data.owner} {timestamp}');
            break;
        case isset($data['status']):
            $desc = __('<b>{somebody}</b> changed the status to <strong>{<TicketStatus>data.status}</strong> {timestamp}');
            break;
        case isset($data['fields']):
            $fields = $changes = array();
            foreach (DynamicFormField::objects()->filter(array(
                'id__in' => array_keys($data['fields'])
            )) as $F) {
                $fields[$F->id] = $F;
            }
            foreach ($data['fields'] as $id=>$f) {
                $field = $fields[$id];
                if ($mode == self::MODE_CLIENT && !$field->isVisibleToUsers())
                    continue;
                list($old, $new) = $f;
                $impl = $field->getImpl($field);
                $before = $impl->to_php($old);
                $after = $impl->to_php($new);
                $changes[] = sprintf('<strong>%s</strong> %s',
                    $field->getLocal('label'), $impl->whatChanged($before, $after));
            }
            // Fallthrough to other editable fields
        case isset($data['topic_id']):
        case isset($data['sla_id']):
        case isset($data['source']):
        case isset($data['user_id']):
        case isset($data['duedate']):
            $base = __('Updated by <b>{somebody}</b> {timestamp} — %s');
            foreach (array(
                'topic_id' => array(__('Help Topic'), array('Topic', 'getTopicName')),
                'sla_id' => array(__('SLA'), array('SLA', 'getSLAName')),
                'duedate' => array(__('Due Date'), array('Format', 'date')),
                'user_id' => array(__('Ticket Owner'), array('User', 'getNameById')),
                'source' => array(__('Source'), null)
            ) as $f => $info) {
                if (isset($data[$f])) {
                    list($name, $desc) = $info;
                    list($old, $new) = $data[$f];
                    if ($desc && is_callable($desc)) {
                        $new = call_user_func($desc, $new);
                        if ($old)
                            $old = call_user_func($desc, $old);
                    }
                    if ($old and $new) {
                        $changes[] = sprintf(
                            __('<strong>%1$s</strong> changed from <strong>%2$s</strong> to <strong>%3$s</strong>'),
                            Format::htmlchars($name), Format::htmlchars($old), Format::htmlchars($new)
                        );
                    }
                    elseif ($new) {
                        $changes[] = sprintf(
                            __('<strong>%1$s</strong> set to <strong>%2$s</strong>'),
                            Format::htmlchars($name), Format::htmlchars($new)
                        );
                    }
                    else {
                        $changes[] = sprintf(
                            __('unset <strong>%1$s</strong>'),
                            Format::htmlchars($name)
                        );
                    }
                }
            }
            $desc = $changes
                ? sprintf($base, implode(', ', $changes)) : '';
            break;
        }

        return $this->template($desc);
    }
}

class OverdueEvent extends ThreadEvent {
    static $icon = 'time';
    static $state = 'overdue';

    function getDescription($mode=self::MODE_STAFF) {
        return $this->template(__('Flagged as overdue by the system {timestamp}'));
    }
}

class ReopenEvent extends ThreadEvent {
    static $icon = 'rotate-right';
    static $state = 'reopened';

    function getDescription($mode=self::MODE_STAFF) {
        return $this->template(__('Reopened by <b>{somebody}</b> {timestamp}'));
    }
}

class ResendEvent extends ThreadEvent {
    static $icon = 'reply-all icon-flip-horizontal';
    static $state = 'resent';

    function getDescription($mode=self::MODE_STAFF) {
        return $this->template(__('<b>{somebody}</b> resent <strong><a href="#thread-entry-{data.entry}">a previous response</a></strong> {timestamp}'));
    }
}

class TransferEvent extends ThreadEvent {
    static $icon = 'share-alt';