diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index e4bf8903..e00805e9 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -1,3620 +1,3614 @@
 <?php
 
 /**
  * Calendar plugin for Roundcube webmail
  *
  * @author Lazlo Westerhof <hello@lazlo.me>
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2010, Lazlo Westerhof <hello@lazlo.me>
  * Copyright (C) 2014-2015, Kolab Systems AG <contact@kolabsys.com>
  *
  * 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/>.
  */
 
 class calendar extends rcube_plugin
 {
   const FREEBUSY_UNKNOWN = 0;
   const FREEBUSY_FREE = 1;
   const FREEBUSY_BUSY = 2;
   const FREEBUSY_TENTATIVE = 3;
   const FREEBUSY_OOF = 4;
 
   const SESSION_KEY = 'calendar_temp';
 
   public $task = '?(?!logout).*';
   public $rc;
   public $lib;
   public $resources_dir;
   public $home;  // declare public to be used in other classes
   public $urlbase;
   public $timezone;
   public $timezone_offset;
   public $gmt_offset;
   public $ui;
 
   public $defaults = array(
     'calendar_default_view' => "agendaWeek",
     'calendar_timeslots'    => 2,
     'calendar_work_start'   => 6,
     'calendar_work_end'     => 18,
     'calendar_agenda_range' => 60,
     'calendar_agenda_sections' => 'smart',
     'calendar_event_coloring'  => 0,
     'calendar_time_indicator'  => true,
     'calendar_allow_invite_shared' => false,
     'calendar_itip_send_option'    => 3,
     'calendar_itip_after_action'   => 0,
   );
 
 // These are implemented with __get()
 //  private $ical;
 //  private $itip;
 //  private $driver;
 
 
   /**
    * Plugin initialization.
    */
   function init()
   {
     $this->rc = rcube::get_instance();
 
     $this->register_task('calendar', 'calendar');
 
     // load calendar configuration
     $this->load_config();
 
     // catch iTIP confirmation requests that don're require a valid session
     if ($this->rc->action == 'attend' && !empty($_REQUEST['_t'])) {
       $this->add_hook('startup', array($this, 'itip_attend_response'));
     }
     else if ($this->rc->action == 'feed' && !empty($_REQUEST['_cal'])) {
       $this->add_hook('startup', array($this, 'ical_feed_export'));
     }
     else if ($this->rc->task != 'login') {
       // default startup routine
       $this->add_hook('startup', array($this, 'startup'));
     }
 
     $this->add_hook('user_delete', array($this, 'user_delete'));
   }
 
   /**
    * Setup basic plugin environment and UI
    */
   protected function setup()
   {
     $this->require_plugin('libcalendaring');
     $this->require_plugin('libkolab');
 
     $this->lib             = libcalendaring::get_instance();
     $this->timezone        = $this->lib->timezone;
     $this->gmt_offset      = $this->lib->gmt_offset;
     $this->dst_active      = $this->lib->dst_active;
     $this->timezone_offset = $this->gmt_offset / 3600 - $this->dst_active;
 
     // load localizations
     $this->add_texts('localization/', $this->rc->task == 'calendar' && (!$this->rc->action || $this->rc->action == 'print'));
 
     require($this->home . '/lib/calendar_ui.php');
     $this->ui = new calendar_ui($this);
   }
 
   /**
    * Startup hook
    */
   public function startup($args)
   {
     // the calendar module can be enabled/disabled by the kolab_auth plugin
     if ($this->rc->config->get('calendar_disabled', false) || !$this->rc->config->get('calendar_enabled', true))
         return;
 
     $this->setup();
 
     // load Calendar user interface
     if (!$this->rc->output->ajax_call && (!$this->rc->output->env['framed'] || $args['action'] == 'preview')) {
       $this->ui->init();
 
       // settings are required in (almost) every GUI step
       if ($args['action'] != 'attend')
         $this->rc->output->set_env('calendar_settings', $this->load_settings());
     }
 
     if ($args['task'] == 'calendar' && $args['action'] != 'save-pref') {
       if ($args['action'] != 'upload') {
         $this->load_driver();
       }
 
       // register calendar actions
       $this->register_action('index', array($this, 'calendar_view'));
       $this->register_action('event', array($this, 'event_action'));
       $this->register_action('calendar', array($this, 'calendar_action'));
       $this->register_action('count', array($this, 'count_events'));
       $this->register_action('load_events', array($this, 'load_events'));
       $this->register_action('export_events', array($this, 'export_events'));
       $this->register_action('import_events', array($this, 'import_events'));
       $this->register_action('upload', array($this, 'attachment_upload'));
       $this->register_action('get-attachment', array($this, 'attachment_get'));
       $this->register_action('freebusy-status', array($this, 'freebusy_status'));
       $this->register_action('freebusy-times', array($this, 'freebusy_times'));
       $this->register_action('randomdata', array($this, 'generate_randomdata'));
       $this->register_action('print', array($this,'print_view'));
       $this->register_action('mailimportitip', array($this, 'mail_import_itip'));
       $this->register_action('mailimportattach', array($this, 'mail_import_attachment'));
       $this->register_action('dialog-ui', array($this, 'mail_message2event'));
       $this->register_action('check-recent', array($this, 'check_recent'));
       $this->register_action('itip-status', array($this, 'event_itip_status'));
       $this->register_action('itip-remove', array($this, 'event_itip_remove'));
       $this->register_action('itip-decline-reply', array($this, 'mail_itip_decline_reply'));
       $this->register_action('itip-delegate', array($this, 'mail_itip_delegate'));
       $this->register_action('resources-list', array($this, 'resources_list'));
       $this->register_action('resources-owner', array($this, 'resources_owner'));
       $this->register_action('resources-calendar', array($this, 'resources_calendar'));
       $this->register_action('resources-autocomplete', array($this, 'resources_autocomplete'));
       $this->add_hook('refresh', array($this, 'refresh'));
 
       // remove undo information...
       if ($undo = $_SESSION['calendar_event_undo']) {
         // ...after timeout
         $undo_time = $this->rc->config->get('undo_timeout', 0);
         if ($undo['ts'] < time() - $undo_time) {
           $this->rc->session->remove('calendar_event_undo');
           // @TODO: do EXPUNGE on kolab objects?
         }
       }
     }
     else if ($args['task'] == 'settings') {
       // add hooks for Calendar settings
       $this->add_hook('preferences_sections_list', array($this, 'preferences_sections_list'));
       $this->add_hook('preferences_list', array($this, 'preferences_list'));
       $this->add_hook('preferences_save', array($this, 'preferences_save')); 
     }
     else if ($args['task'] == 'mail') {
       // hooks to catch event invitations on incoming mails
       if ($args['action'] == 'show' || $args['action'] == 'preview') {
         $this->add_hook('template_object_messagebody', array($this, 'mail_messagebody_html'));
       }
 
       // add 'Create event' item to message menu
       if ($this->api->output->type == 'html' && $_GET['_rel'] != 'event') {
         $this->api->add_content(html::tag('li', null, 
           $this->api->output->button(array(
             'command'  => 'calendar-create-from-mail',
             'label'    => 'calendar.createfrommail',
             'type'     => 'link',
             'classact' => 'icon calendarlink active',
             'class'    => 'icon calendarlink',
             'innerclass' => 'icon calendar',
           ))),
           'messagemenu');
 
         $this->api->output->add_label('calendar.createfrommail');
       }
 
       $this->add_hook('messages_list', array($this, 'mail_messages_list'));
       $this->add_hook('message_compose', array($this, 'mail_message_compose'));
     }
     else if ($args['task'] == 'addressbook') {
       if ($this->rc->config->get('calendar_contact_birthdays')) {
         $this->add_hook('contact_update', array($this, 'contact_update'));
         $this->add_hook('contact_create', array($this, 'contact_update'));
       }
     }
 
     // add hooks to display alarms
     $this->add_hook('pending_alarms', array($this, 'pending_alarms'));
     $this->add_hook('dismiss_alarms', array($this, 'dismiss_alarms'));
   }
 
   /**
    * Helper method to load the backend driver according to local config
    */
   private function load_driver()
   {
     if (is_object($this->driver))
       return;
 
     $driver_name = $this->rc->config->get('calendar_driver', 'database');
     $driver_class = $driver_name . '_driver';
 
     require_once($this->home . '/drivers/calendar_driver.php');
     require_once($this->home . '/drivers/' . $driver_name . '/' . $driver_class . '.php');
 
     $this->driver = new $driver_class($this);
 
     if ($this->driver->undelete)
       $this->driver->undelete = $this->rc->config->get('undo_timeout', 0) > 0;
   }
 
   /**
    * Load iTIP functions
    */
   private function load_itip()
   {
     if (!$this->itip) {
       require_once($this->home . '/lib/calendar_itip.php');
       $this->itip = new calendar_itip($this);
       
       if ($this->rc->config->get('kolab_invitation_calendars'))
         $this->itip->set_rsvp_actions(array('accepted','tentative','declined','delegated','needs-action'));
     }
 
     return $this->itip;
   }
 
   /**
    * Load iCalendar functions
    */
   public function get_ical()
   {
     if (!$this->ical) {
       $this->ical = libcalendaring::get_ical();
     }
     
     return $this->ical;
   }
 
   /**
    * Get properties of the calendar this user has specified as default
    */
   public function get_default_calendar($sensitivity = null, $calendars = null)
   {
     if ($calendars === null) {
       $calendars = $this->driver->list_calendars(calendar_driver::FILTER_PERSONAL | calendar_driver::FILTER_WRITEABLE);
     }
 
     $default_id = $this->rc->config->get('calendar_default_calendar');
     $calendar   = $calendars[$default_id] ?: null;
 
     if (!$calendar || $sensitivity) {
       foreach ($calendars as $cal) {
         if ($sensitivity && $cal['subtype'] == $sensitivity) {
           $calendar = $cal;
           break;
         }
         if ($cal['default'] && $cal['editable']) {
           $calendar = $cal;
         }
         if ($cal['editable']) {
           $first = $cal;
         }
       }
     }
 
     return $calendar ?: $first;
   }
 
 
   /**
    * Render the main calendar view from skin template
    */
   function calendar_view()
   {
     $this->rc->output->set_pagetitle($this->gettext('calendar'));
 
     // Add CSS stylesheets to the page header
     $this->ui->addCSS();
 
     // Add JS files to the page header
     $this->ui->addJS();
 
     $this->ui->init_templates();
     $this->rc->output->add_label('lowest','low','normal','high','highest','delete','cancel','uploading','noemailwarning','close');
 
     // initialize attendees autocompletion
     $this->rc->autocomplete_init();
 
     $this->rc->output->set_env('timezone', $this->timezone->getName());
     $this->rc->output->set_env('calendar_driver', $this->rc->config->get('calendar_driver'), false);
     $this->rc->output->set_env('calendar_resources', (bool)$this->rc->config->get('calendar_resources_driver'));
     $this->rc->output->set_env('identities-selector', $this->ui->identity_select(array(
         'id'         => 'edit-identities-list',
         'aria-label' => $this->gettext('roleorganizer'),
         'class'      => 'form-control custom-select',
     )));
 
     $view = rcube_utils::get_input_value('view', rcube_utils::INPUT_GPC);
     if (in_array($view, array('agendaWeek', 'agendaDay', 'month', 'table')))
       $this->rc->output->set_env('view', $view);
 
     if ($date = rcube_utils::get_input_value('date', rcube_utils::INPUT_GPC))
       $this->rc->output->set_env('date', $date);
 
     if ($msgref = rcube_utils::get_input_value('itip', rcube_utils::INPUT_GPC))
       $this->rc->output->set_env('itip_events', $this->itip_events($msgref));
 
     $this->rc->output->send("calendar.calendar");
   }
 
   /**
    * Handler for preferences_sections_list hook.
    * Adds Calendar settings sections into preferences sections list.
    *
    * @param array Original parameters
    * @return array Modified parameters
    */
   function preferences_sections_list($p)
   {
     $p['list']['calendar'] = array(
       'id' => 'calendar', 'section' => $this->gettext('calendar'),
     );
 
     return $p;
   }
 
   /**
    * Handler for preferences_list hook.
    * Adds options blocks into Calendar settings sections in Preferences.
    *
    * @param array Original parameters
    * @return array Modified parameters
    */
   function preferences_list($p)
   {
     if ($p['section'] != 'calendar') {
       return $p;
     }
 
     $no_override = array_flip((array)$this->rc->config->get('dont_override'));
 
     $p['blocks']['view']['name'] = $this->gettext('mainoptions');
 
     if (!isset($no_override['calendar_default_view'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $field_id = 'rcmfd_default_view';
       $select = new html_select(array('name' => '_default_view', 'id' => $field_id));
       $select->add($this->gettext('day'), "agendaDay");
       $select->add($this->gettext('week'), "agendaWeek");
       $select->add($this->gettext('month'), "month");
       $select->add($this->gettext('agenda'), "table");
       $p['blocks']['view']['options']['default_view'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('default_view'))),
         'content' => $select->show($this->rc->config->get('calendar_default_view', $this->defaults['calendar_default_view'])),
       );
     }
 
     if (!isset($no_override['calendar_timeslots'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $field_id = 'rcmfd_timeslot';
       $choices = array('1', '2', '3', '4', '6');
       $select = new html_select(array('name' => '_timeslots', 'id' => $field_id));
       $select->add($choices);
       $p['blocks']['view']['options']['timeslots'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('timeslots'))),
         'content' => $select->show(strval($this->rc->config->get('calendar_timeslots', $this->defaults['calendar_timeslots']))),
       );
     }
 
     if (!isset($no_override['calendar_first_day'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $field_id = 'rcmfd_firstday';
       $select = new html_select(array('name' => '_first_day', 'id' => $field_id));
       $select->add($this->gettext('sunday'), '0');
       $select->add($this->gettext('monday'), '1');
       $select->add($this->gettext('tuesday'), '2');
       $select->add($this->gettext('wednesday'), '3');
       $select->add($this->gettext('thursday'), '4');
       $select->add($this->gettext('friday'), '5');
       $select->add($this->gettext('saturday'), '6');
       $p['blocks']['view']['options']['first_day'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('first_day'))),
         'content' => $select->show(strval($this->rc->config->get('calendar_first_day', $this->defaults['calendar_first_day']))),
       );
     }
 
     if (!isset($no_override['calendar_first_hour'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $time_format = $this->rc->config->get('time_format', libcalendaring::to_php_date_format($this->rc->config->get('calendar_time_format', $this->defaults['calendar_time_format'])));
       $select_hours = new html_select();
       for ($h = 0; $h < 24; $h++)
         $select_hours->add(date($time_format, mktime($h, 0, 0)), $h);
 
       $field_id = 'rcmfd_firsthour';
       $p['blocks']['view']['options']['first_hour'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('first_hour'))),
         'content' => $select_hours->show($this->rc->config->get('calendar_first_hour', $this->defaults['calendar_first_hour']), array('name' => '_first_hour', 'id' => $field_id)),
       );
     }
 
     if (!isset($no_override['calendar_work_start'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $field_id   = 'rcmfd_workstart';
       $work_start = $this->rc->config->get('calendar_work_start', $this->defaults['calendar_work_start']);
       $work_end   = $this->rc->config->get('calendar_work_end', $this->defaults['calendar_work_end']);
       $p['blocks']['view']['options']['workinghours'] = array(
         'title'   => html::label($field_id, rcube::Q($this->gettext('workinghours'))),
         'content' => html::div('input-group',
           $select_hours->show($work_start, array('name' => '_work_start', 'id' => $field_id))
           . html::span('input-group-append input-group-prepend', html::span('input-group-text',' &mdash; '))
           . $select_hours->show($work_end, array('name' => '_work_end', 'id' => $field_id))
         )
       );
     }
 
     if (!isset($no_override['calendar_event_coloring'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $field_id = 'rcmfd_coloring';
       $select_colors = new html_select(array('name' => '_event_coloring', 'id' => $field_id));
       $select_colors->add($this->gettext('coloringmode0'), 0);
       $select_colors->add($this->gettext('coloringmode1'), 1);
       $select_colors->add($this->gettext('coloringmode2'), 2);
       $select_colors->add($this->gettext('coloringmode3'), 3);
 
       $p['blocks']['view']['options']['eventcolors'] = array(
         'title'   => html::label($field_id, rcube::Q($this->gettext('eventcoloring'))),
         'content' => $select_colors->show($this->rc->config->get('calendar_event_coloring', $this->defaults['calendar_event_coloring'])),
       );
     }
 
     // loading driver is expensive, don't do it if not needed
     $this->load_driver();
 
     if (!isset($no_override['calendar_default_alarm_type']) || !isset($no_override['calendar_default_alarm_offset'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $alarm_type = $alarm_offset = '';
 
       if (!isset($no_override['calendar_default_alarm_type'])) {
         $field_id    = 'rcmfd_alarm';
         $select_type = new html_select(array('name' => '_alarm_type', 'id' => $field_id));
         $select_type->add($this->gettext('none'), '');
 
         foreach ($this->driver->alarm_types as $type) {
           $select_type->add($this->rc->gettext(strtolower("alarm{$type}option"), 'libcalendaring'), $type);
         }
 
         $alarm_type = $select_type->show($this->rc->config->get('calendar_default_alarm_type', ''));
       }
 
       if (!isset($no_override['calendar_default_alarm_offset'])) {
         $field_id      = 'rcmfd_alarm';
         $input_value   = new html_inputfield(array('name' => '_alarm_value', 'id' => $field_id . 'value', 'size' => 3));
         $select_offset = new html_select(array('name' => '_alarm_offset', 'id' => $field_id . 'offset'));
 
         foreach (array('-M','-H','-D','+M','+H','+D') as $trigger) {
           $select_offset->add($this->rc->gettext('trigger' . $trigger, 'libcalendaring'), $trigger);
         }
 
         $preset = libcalendaring::parse_alarm_value($this->rc->config->get('calendar_default_alarm_offset', '-15M'));
         $alarm_offset = $input_value->show($preset[0]) . ' ' . $select_offset->show($preset[1]);
       }
 
       $p['blocks']['view']['options']['alarmtype'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('defaultalarmtype'))),
         'content' => html::div('input-group', $alarm_type . ' ' . $alarm_offset),
       );
     }
 
     if (!isset($no_override['calendar_default_calendar'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
       // default calendar selection
       $field_id   = 'rcmfd_default_calendar';
       $filter     = calendar_driver::FILTER_PERSONAL | calendar_driver::FILTER_ACTIVE | calendar_driver::FILTER_INSERTABLE;
       $select_cal = new html_select(array('name' => '_default_calendar', 'id' => $field_id, 'is_escaped' => true));
       foreach ((array)$this->driver->list_calendars($filter) as $id => $prop) {
         $select_cal->add($prop['name'], strval($id));
         if ($prop['default'])
           $default_calendar = $id;
       }
       $p['blocks']['view']['options']['defaultcalendar'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('defaultcalendar'))),
         'content' => $select_cal->show($this->rc->config->get('calendar_default_calendar', $default_calendar)),
       );
     }
 
     if (!isset($no_override['calendar_show_weekno'])) {
       if (!$p['current']) {
         $p['blocks']['view']['content'] = true;
         return $p;
       }
 
       $field_id   = 'rcmfd_show_weekno';
       $select = new html_select(array('name' => '_show_weekno', 'id' => $field_id));
       $select->add($this->gettext('weeknonone'), -1);
       $select->add($this->gettext('weeknodatepicker'), 0);
       $select->add($this->gettext('weeknoall'), 1);
 
       $p['blocks']['view']['options']['show_weekno'] = array(
         'title' => html::label($field_id, rcube::Q($this->gettext('showweekno'))),
         'content' => $select->show(intval($this->rc->config->get('calendar_show_weekno'))),
       );
     }
 
     $p['blocks']['itip']['name'] = $this->gettext('itipoptions');
 
     // Invitations handling
     if (!isset($no_override['calendar_itip_after_action'])) {
       if (!$p['current']) {
         $p['blocks']['itip']['content'] = true;
         return $p;
       }
 
       $field_id = 'rcmfd_after_action';
       $select   = new html_select(array('name' => '_after_action', 'id' => $field_id,
         'onchange' => "\$('#{$field_id}_select')[this.value == 4 ? 'show' : 'hide']()"));
 
       $select->add($this->gettext('afternothing'), '');
       $select->add($this->gettext('aftertrash'), 1);
       $select->add($this->gettext('afterdelete'), 2);
       $select->add($this->gettext('afterflagdeleted'), 3);
       $select->add($this->gettext('aftermoveto'), 4);
 
       $val = $this->rc->config->get('calendar_itip_after_action', $this->defaults['calendar_itip_after_action']);
       if ($val !== null && $val !== '' && !is_int($val)) {
         $folder = $val;
         $val    = 4;
       }
 
       $folders = $this->rc->folder_selector(array(
           'id'            => $field_id . '_select',
           'name'          => '_after_action_folder',
           'maxlength'     => 30,
           'folder_filter' => 'mail',
           'folder_rights' => 'w',
           'style'         => $val !== 4 ? 'display:none' : '',
       ));
 
       $p['blocks']['itip']['options']['after_action'] = array(
         'title'   => html::label($field_id, rcube::Q($this->gettext('afteraction'))),
         'content' => html::div('input-group input-group-combo', $select->show($val) . $folders->show($folder)),
       );
     }
 
     // category definitions
     if (!$this->driver->nocategories && !isset($no_override['calendar_categories'])) {
         $p['blocks']['categories']['name'] = $this->gettext('categories');
 
         if (!$p['current']) {
           $p['blocks']['categories']['content'] = true;
           return $p;
         }
 
         $categories = (array) $this->driver->list_categories();
         $categories_list = '';
         foreach ($categories as $name => $color) {
           $key = md5($name);
           $field_class = 'rcmfd_category_' . str_replace(' ', '_', $name);
           $category_remove = html::span('input-group-append', html::a(array(
               'class'   => 'button icon delete input-group-text',
               'onclick' => '$(this).parent().parent().remove()',
               'title'   => $this->gettext('remove_category'),
               'href'    => '#rcmfd_new_category',
             ), html::span('inner', $this->gettext('delete'))
           ));
           $category_name  = new html_inputfield(array('name' => "_categories[$key]", 'class' => $field_class, 'size' => 30, 'disabled' => $this->driver->categoriesimmutable));
           $category_color = new html_inputfield(array('name' => "_colors[$key]", 'class' => "$field_class colors", 'size' => 6));
           $hidden = $this->driver->categoriesimmutable ? html::tag('input', array('type' => 'hidden', 'name' => "_categories[$key]", 'value' => $name)) : '';
           $categories_list .= $hidden . html::div('input-group', $category_name->show($name) . $category_color->show($color) . $category_remove);
         }
 
         $p['blocks']['categories']['options']['category_' . $name] = array(
           'content' => html::div(array('id' => 'calendarcategories'), $categories_list),
         );
 
         $field_id = 'rcmfd_new_category';
         $new_category = new html_inputfield(array('name' => '_new_category', 'id' => $field_id, 'size' => 30));
         $add_category = html::span('input-group-append', html::a(array(
             'type'    => 'button',
             'class'   => 'button create input-group-text',
             'title'   => $this->gettext('add_category'),
             'onclick' => 'rcube_calendar_add_category()',
             'href'    => '#rcmfd_new_category',
           ), html::span('inner', $this->gettext('add_category'))
         ));
         $p['blocks']['categories']['options']['categories'] = array(
           'content' => html::div('input-group', $new_category->show('') . $add_category),
         );
 
         $this->rc->output->add_label('delete', 'calendar.remove_category');
         $this->rc->output->add_script('function rcube_calendar_add_category() {
           var name = $("#rcmfd_new_category").val();
           if (name.length) {
             var button_label = rcmail.gettext("calendar.remove_category");
             var input = $("<input>").attr({type: "text", name: "_categories[]", size: 30, "class": "form-control"}).val(name);
             var color = $("<input>").attr({type: "text", name: "_colors[]", size: 6, "class": "colors form-control"}).val("000000");
             var button = $("<a>").attr({"class": "button icon delete input-group-text", title: button_label, href: "#rcmfd_new_category"})
               .click(function() { $(this).parent().parent().remove(); })
               .append($("<span>").addClass("inner").text(rcmail.gettext("delete")));
 
             $("<div>").addClass("input-group").append(input).append(color).append($("<span class=\'input-group-append\'>").append(button))
               .appendTo("#calendarcategories");
             color.minicolors(rcmail.env.minicolors_config || {});
             $("#rcmfd_new_category").val("");
           }
         }', 'foot');
 
         $this->rc->output->add_script('$("#rcmfd_new_category").keypress(function(event) {
           if (event.which == 13) {
             rcube_calendar_add_category();
             event.preventDefault();
           }
         });
         ', 'docready');
 
         // load miniColors js/css files
         jqueryui::miniColors();
     }
 
     // virtual birthdays calendar
     if (!isset($no_override['calendar_contact_birthdays'])) {
       $p['blocks']['birthdays']['name'] = $this->gettext('birthdayscalendar');
 
       if (!$p['current']) {
         $p['blocks']['birthdays']['content'] = true;
         return $p;
       }
 
       $field_id = 'rcmfd_contact_birthdays';
       $input    = new html_checkbox(array('name' => '_contact_birthdays', 'id' => $field_id, 'value' => 1, 'onclick' => '$(".calendar_birthday_props").prop("disabled",!this.checked)'));
 
       $p['blocks']['birthdays']['options']['contact_birthdays'] = array(
         'title'   => html::label($field_id, $this->gettext('displaybirthdayscalendar')),
         'content' => $input->show($this->rc->config->get('calendar_contact_birthdays')?1:0),
       );
 
       $input_attrib = array(
         'class' => 'calendar_birthday_props',
         'disabled' => !$this->rc->config->get('calendar_contact_birthdays'),
       );
 
       $sources = array();
       $checkbox = new html_checkbox(array('name' => '_birthday_adressbooks[]') + $input_attrib);
       foreach ($this->rc->get_address_sources(false, true) as $source) {
         $active = in_array($source['id'], (array)$this->rc->config->get('calendar_birthday_adressbooks', array())) ? $source['id'] : '';
         $sources[] = html::tag('li', null, html::label(null, $checkbox->show($active, array('value' => $source['id'])) . rcube::Q($source['realname'] ?: $source['name'])));
       }
 
       $p['blocks']['birthdays']['options']['birthday_adressbooks'] = array(
         'title'   => rcube::Q($this->gettext('birthdayscalendarsources')),
         'content' => html::tag('ul', 'proplist', implode("\n", $sources)),
       );
 
       $field_id = 'rcmfd_birthdays_alarm';
       $select_type = new html_select(array('name' => '_birthdays_alarm_type', 'id' => $field_id) + $input_attrib);
       $select_type->add($this->gettext('none'), '');
       foreach ($this->driver->alarm_types as $type) {
         $select_type->add($this->rc->gettext(strtolower("alarm{$type}option"), 'libcalendaring'), $type);
       }
 
       $input_value = new html_inputfield(array('name' => '_birthdays_alarm_value', 'id' => $field_id . 'value', 'size' => 3) + $input_attrib);
       $select_offset = new html_select(array('name' => '_birthdays_alarm_offset', 'id' => $field_id . 'offset') + $input_attrib);
       foreach (array('-M','-H','-D') as $trigger)
         $select_offset->add($this->rc->gettext('trigger' . $trigger, 'libcalendaring'), $trigger);
 
       $preset      = libcalendaring::parse_alarm_value($this->rc->config->get('calendar_birthdays_alarm_offset', '-1D'));
       $preset_type = $this->rc->config->get('calendar_birthdays_alarm_type', '');
 
       $p['blocks']['birthdays']['options']['birthdays_alarmoffset'] = array(
         'title'   => html::label($field_id, rcube::Q($this->gettext('showalarms'))),
         'content' => html::div('input-group', $select_type->show($preset_type) . $input_value->show($preset[0]) . ' ' . $select_offset->show($preset[1])),
       );
     }
 
     return $p;
   }
 
   /**
    * Handler for preferences_save hook.
    * Executed on Calendar settings form submit.
    *
    * @param array Original parameters
    * @return array Modified parameters
    */
   function preferences_save($p)
   {
     if ($p['section'] == 'calendar') {
       $this->load_driver();
 
       // compose default alarm preset value
       $alarm_offset  = rcube_utils::get_input_value('_alarm_offset', rcube_utils::INPUT_POST);
       $alarm_value   = rcube_utils::get_input_value('_alarm_value', rcube_utils::INPUT_POST);
       $default_alarm = $alarm_offset[0] . intval($alarm_value) . $alarm_offset[1];
 
       $birthdays_alarm_offset = rcube_utils::get_input_value('_birthdays_alarm_offset', rcube_utils::INPUT_POST);
       $birthdays_alarm_value  = rcube_utils::get_input_value('_birthdays_alarm_value', rcube_utils::INPUT_POST);
       $birthdays_alarm_value  = $birthdays_alarm_offset[0] . intval($birthdays_alarm_value) . $birthdays_alarm_offset[1];
 
       $p['prefs'] = array(
         'calendar_default_view' => rcube_utils::get_input_value('_default_view', rcube_utils::INPUT_POST),
         'calendar_timeslots'    => intval(rcube_utils::get_input_value('_timeslots', rcube_utils::INPUT_POST)),
         'calendar_first_day'    => intval(rcube_utils::get_input_value('_first_day', rcube_utils::INPUT_POST)),
         'calendar_first_hour'   => intval(rcube_utils::get_input_value('_first_hour', rcube_utils::INPUT_POST)),
         'calendar_work_start'   => intval(rcube_utils::get_input_value('_work_start', rcube_utils::INPUT_POST)),
         'calendar_work_end'     => intval(rcube_utils::get_input_value('_work_end', rcube_utils::INPUT_POST)),
         'calendar_show_weekno'  => intval(rcube_utils::get_input_value('_show_weekno', rcube_utils::INPUT_POST)),
         'calendar_event_coloring'       => intval(rcube_utils::get_input_value('_event_coloring', rcube_utils::INPUT_POST)),
         'calendar_default_alarm_type'   => rcube_utils::get_input_value('_alarm_type', rcube_utils::INPUT_POST),
         'calendar_default_alarm_offset' => $default_alarm,
         'calendar_default_calendar'     => rcube_utils::get_input_value('_default_calendar', rcube_utils::INPUT_POST),
         'calendar_date_format' => null,  // clear previously saved values
         'calendar_time_format' => null,
         'calendar_contact_birthdays'    => rcube_utils::get_input_value('_contact_birthdays', rcube_utils::INPUT_POST) ? true : false,
         'calendar_birthday_adressbooks' => (array) rcube_utils::get_input_value('_birthday_adressbooks', rcube_utils::INPUT_POST),
         'calendar_birthdays_alarm_type'   => rcube_utils::get_input_value('_birthdays_alarm_type', rcube_utils::INPUT_POST),
         'calendar_birthdays_alarm_offset' => $birthdays_alarm_value ?: null,
         'calendar_itip_after_action'      => intval(rcube_utils::get_input_value('_after_action', rcube_utils::INPUT_POST)),
       );
 
       if ($p['prefs']['calendar_itip_after_action'] == 4) {
         $p['prefs']['calendar_itip_after_action'] = rcube_utils::get_input_value('_after_action_folder', rcube_utils::INPUT_POST, true);
       }
 
       // categories
       if (!$this->driver->nocategories) {
         $old_categories = $new_categories = array();
         foreach ($this->driver->list_categories() as $name => $color) {
           $old_categories[md5($name)] = $name;
         }
 
         $categories = (array) rcube_utils::get_input_value('_categories', rcube_utils::INPUT_POST);
         $colors     = (array) rcube_utils::get_input_value('_colors', rcube_utils::INPUT_POST);
 
         foreach ($categories as $key => $name) {
           if (!isset($colors[$key])) {
             continue;
           }
 
           $color = preg_replace('/^#/', '', strval($colors[$key]));
 
           // rename categories in existing events -> driver's job
           if ($oldname = $old_categories[$key]) {
             $this->driver->replace_category($oldname, $name, $color);
             unset($old_categories[$key]);
           }
           else
             $this->driver->add_category($name, $color);
 
           $new_categories[$name] = $color;
         }
 
         // these old categories have been removed, alter events accordingly -> driver's job
         foreach ((array)$old_categories[$key] as $key => $name) {
           $this->driver->remove_category($name);
         }
 
         $p['prefs']['calendar_categories'] = $new_categories;
       }
     }
 
     return $p;
   }
 
   /**
    * Dispatcher for calendar actions initiated by the client
    */
   function calendar_action()
   {
     $action = rcube_utils::get_input_value('action', rcube_utils::INPUT_GPC);
     $cal    = rcube_utils::get_input_value('c', rcube_utils::INPUT_GPC);
     $success = $reload = false;
 
     if (isset($cal['showalarms']))
       $cal['showalarms'] = intval($cal['showalarms']);
 
     switch ($action) {
       case "form-new":
       case "form-edit":
         echo $this->ui->calendar_editform($action, $cal);
         exit;
       case "new":
         $success = $this->driver->create_calendar($cal);
         $reload = true;
         break;
       case "edit":
         $success = $this->driver->edit_calendar($cal);
         $reload = true;
         break;
       case "delete":
         if ($success = $this->driver->delete_calendar($cal))
           $this->rc->output->command('plugin.destroy_source', array('id' => $cal['id']));
         break;
       case "subscribe":
         if (!$this->driver->subscribe_calendar($cal))
           $this->rc->output->show_message($this->gettext('errorsaving'), 'error');
         else {
           $calendars = $this->driver->list_calendars();
           $calendar  = $calendars[$cal['id']];
 
           // find parent folder and check if it's a "user calendar"
           // if it's also activated we need to refresh it (#5340)
           while ($calendar['parent']) {
             if (isset($calendars[$calendar['parent']]))
               $calendar = $calendars[$calendar['parent']];
             else
               break;
           }
 
           if ($calendar['id'] != $cal['id'] && $calendar['active'] && $calendar['group'] == "other user")
             $this->rc->output->command('plugin.refresh_source', $calendar['id']);
         }
         return;
       case "search":
         $results    = array();
         $color_mode = $this->rc->config->get('calendar_event_coloring', $this->defaults['calendar_event_coloring']);
         $query      = rcube_utils::get_input_value('q', rcube_utils::INPUT_GPC);
         $source     = rcube_utils::get_input_value('source', rcube_utils::INPUT_GPC);
 
         foreach ((array) $this->driver->search_calendars($query, $source) as $id => $prop) {
           $editname = $prop['editname'];
           unset($prop['editname']);  // force full name to be displayed
           $prop['active'] = false;
 
           // let the UI generate HTML and CSS representation for this calendar
           $html = $this->ui->calendar_list_item($id, $prop, $jsenv);
           $cal = $jsenv[$id];
           $cal['editname'] = $editname;
           $cal['html'] = $html;
           if (!empty($prop['color']))
             $cal['css'] = $this->ui->calendar_css_classes($id, $prop, $color_mode);
 
           $results[] = $cal;
         }
         // report more results available
         if ($this->driver->search_more_results)
           $this->rc->output->show_message('autocompletemore', 'notice');
 
         $this->rc->output->command('multi_thread_http_response', $results, rcube_utils::get_input_value('_reqid', rcube_utils::INPUT_GPC));
         return;
     }
 
     if ($success)
       $this->rc->output->show_message('successfullysaved', 'confirmation');
     else {
       $error_msg = $this->gettext('errorsaving') . ($this->driver->last_error ? ': ' . $this->driver->last_error :'');
       $this->rc->output->show_message($error_msg, 'error');
     }
 
     $this->rc->output->command('plugin.unlock_saving');
 
     if ($success && $reload)
       $this->rc->output->command('plugin.reload_view');
   }
 
 
   /**
    * Dispatcher for event actions initiated by the client
    */
   function event_action()
   {
     $action = rcube_utils::get_input_value('action', rcube_utils::INPUT_GPC);
     $event  = rcube_utils::get_input_value('e', rcube_utils::INPUT_POST, true);
     $success = $reload = $got_msg = false;
 
     // force notify if hidden + active
     if ((int)$this->rc->config->get('calendar_itip_send_option', $this->defaults['calendar_itip_send_option']) === 1)
       $event['_notify'] = 1;
 
     // read old event data in order to find changes
     if (($event['_notify'] || $event['_decline']) && $action != 'new') {
       $old = $this->driver->get_event($event);
 
       // load main event if savemode is 'all' or if deleting 'future' events
       if (($event['_savemode'] == 'all' || ($event['_savemode'] == 'future' && $action == 'remove' && !$event['_decline'])) && $old['recurrence_id']) {
         $old['id'] = $old['recurrence_id'];
         $old = $this->driver->get_event($old);
       }
     }
 
     switch ($action) {
       case "new":
         // create UID for new event
         $event['uid'] = $this->generate_uid();
         if (!$this->write_preprocess($event, $action)) {
           $got_msg = true;
         }
         else if ($success = $this->driver->new_event($event)) {
           $event['id'] = $event['uid'];
           $event['_savemode'] = 'all';
           $this->cleanup_event($event);
           $this->event_save_success($event, null, $action, true);
         }
         $reload = $success && $event['recurrence'] ? 2 : 1;
         break;
         
       case "edit":
         if (!$this->write_preprocess($event, $action)) {
           $got_msg = true;
         }
         else if ($success = $this->driver->edit_event($event)) {
           $this->cleanup_event($event);
           $this->event_save_success($event, $old, $action, $success);
         }
         $reload = $success && ($event['recurrence'] || $event['_savemode'] || $event['_fromcalendar']) ? 2 : 1;
         break;
       
       case "resize":
         if (!$this->write_preprocess($event, $action)) {
           $got_msg = true;
         }
         else if ($success = $this->driver->resize_event($event)) {
           $this->event_save_success($event, $old, $action, $success);
         }
         $reload = $event['_savemode'] ? 2 : 1;
         break;
       
       case "move":
         if (!$this->write_preprocess($event, $action)) {
           $got_msg = true;
         }
         else if ($success = $this->driver->move_event($event)) {
           $this->event_save_success($event, $old, $action, $success);
         }
         $reload = $success && $event['_savemode'] ? 2 : 1;
         break;
       
       case "remove":
         // remove previous deletes
         $undo_time = $this->driver->undelete ? $this->rc->config->get('undo_timeout', 0) : 0;
         $this->rc->session->remove('calendar_event_undo');
         
         // search for event if only UID is given
         if (!isset($event['calendar']) && $event['uid']) {
           if (!($event = $this->driver->get_event($event, calendar_driver::FILTER_WRITEABLE))) {
             break;
           }
           $undo_time = 0;
         }
 
         $success = $this->driver->remove_event($event, $undo_time < 1);
         $reload = (!$success || $event['_savemode']) ? 2 : 1;
 
         if ($undo_time > 0 && $success) {
           $_SESSION['calendar_event_undo'] = array('ts' => time(), 'data' => $event);
           // display message with Undo link.
           $msg = html::span(null, $this->gettext('successremoval'))
             . ' ' . html::a(array('onclick' => sprintf("%s.http_request('event', 'action=undo', %s.display_message('', 'loading'))",
               rcmail_output::JS_OBJECT_NAME, rcmail_output::JS_OBJECT_NAME)), $this->gettext('undo'));
           $this->rc->output->show_message($msg, 'confirmation', null, true, $undo_time);
           $got_msg = true;
         }
         else if ($success) {
           $this->rc->output->show_message('calendar.successremoval', 'confirmation');
           $got_msg = true;
         }
 
         // send cancellation for the main event
         if ($event['_savemode'] == 'all') {
           unset($old['_instance'], $old['recurrence_date'], $old['recurrence_id']);
         }
         // send an update for the main event's recurrence rule instead of a cancellation message
         else if ($event['_savemode'] == 'future' && $success !== false && $success !== true) {
           $event['_savemode'] = 'all';  // force event_save_success() to load master event
           $action = 'edit';
           $success = true;
         }
 
         // send iTIP reply that participant has declined the event
         if ($success && $event['_decline']) {
           $emails = $this->get_user_emails();
           foreach ($old['attendees'] as $i => $attendee) {
             if ($attendee['role'] == 'ORGANIZER')
               $organizer = $attendee;
             else if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
               $old['attendees'][$i]['status'] = 'DECLINED';
               $reply_sender = $attendee['email'];
             }
           }
 
           if ($event['_savemode'] == 'future' && $event['id'] != $old['id']) {
             $old['thisandfuture'] = true;
           }
 
           $itip = $this->load_itip();
           $itip->set_sender_email($reply_sender);
           if ($organizer && $itip->send_itip_message($old, 'REPLY', $organizer, 'itipsubjectdeclined', 'itipmailbodydeclined'))
             $this->rc->output->command('display_message', $this->gettext(array('name' => 'sentresponseto', 'vars' => array('mailto' => $organizer['name'] ? $organizer['name'] : $organizer['email']))), 'confirmation');
           else
             $this->rc->output->command('display_message', $this->gettext('itipresponseerror'), 'error');
         }
         else if ($success) {
           $this->event_save_success($event, $old, $action, $success);
         }
         break;
 
       case "undo":
         // Restore deleted event
         $event  = $_SESSION['calendar_event_undo']['data'];
 
         if ($event)
           $success = $this->driver->restore_event($event);
 
         if ($success) {
           $this->rc->session->remove('calendar_event_undo');
           $this->rc->output->show_message('calendar.successrestore', 'confirmation');
           $got_msg = true;
           $reload = 2;
         }
 
         break;
 
       case "rsvp":
         $itip_sending  = $this->rc->config->get('calendar_itip_send_option', $this->defaults['calendar_itip_send_option']);
         $status        = rcube_utils::get_input_value('status', rcube_utils::INPUT_POST);
         $attendees     = rcube_utils::get_input_value('attendees', rcube_utils::INPUT_POST);
         $reply_comment = $event['comment'];
 
         $this->write_preprocess($event, 'edit');
         $ev = $this->driver->get_event($event);
         $ev['attendees'] = $event['attendees'];
         $ev['free_busy'] = $event['free_busy'];
         $ev['_savemode'] = $event['_savemode'];
         $ev['comment']   = $reply_comment;
 
         // send invitation to delegatee + add it as attendee
         if ($status == 'delegated' && $event['to']) {
           $itip = $this->load_itip();
           if ($itip->delegate_to($ev, $event['to'], (bool)$event['rsvp'], $attendees)) {
             $this->rc->output->show_message('calendar.itipsendsuccess', 'confirmation');
             $noreply = false;
           }
         }
 
         $event = $ev;
 
         // compose a list of attendees affected by this change
         $updated_attendees = array_filter(array_map(function($j) use ($event) {
           return $event['attendees'][$j];
         }, $attendees));
 
         if ($success = $this->driver->edit_rsvp($event, $status, $updated_attendees)) {
           $noreply = rcube_utils::get_input_value('noreply', rcube_utils::INPUT_GPC);
           $noreply = intval($noreply) || $status == 'needs-action' || $itip_sending === 0;
           $reload  = $event['calendar'] != $ev['calendar'] || $event['recurrence'] ? 2 : 1;
           $organizer = null;
           $emails = $this->get_user_emails();
 
           foreach ($event['attendees'] as $i => $attendee) {
             if ($attendee['role'] == 'ORGANIZER') {
               $organizer = $attendee;
             }
             else if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
               $reply_sender = $attendee['email'];
             }
           }
 
           if (!$noreply) {
             $itip = $this->load_itip();
             $itip->set_sender_email($reply_sender);
             $event['thisandfuture'] = $event['_savemode'] == 'future';
             if ($organizer && $itip->send_itip_message($event, 'REPLY', $organizer, 'itipsubject' . $status, 'itipmailbody' . $status))
               $this->rc->output->command('display_message', $this->gettext(array('name' => 'sentresponseto', 'vars' => array('mailto' => $organizer['name'] ? $organizer['name'] : $organizer['email']))), 'confirmation');
             else
               $this->rc->output->command('display_message', $this->gettext('itipresponseerror'), 'error');
           }
 
           // refresh all calendars
           if ($event['calendar'] != $ev['calendar']) {
             $this->rc->output->command('plugin.refresh_calendar', array('source' => null, 'refetch' => true));
             $reload = 0;
           }
         }
         break;
 
       case "dismiss":
         $event['ids'] = explode(',', $event['id']);
         $plugin = $this->rc->plugins->exec_hook('dismiss_alarms', $event);
         $success = $plugin['success'];
         foreach ($event['ids'] as $id) {
             if (strpos($id, 'cal:') === 0)
                 $success |= $this->driver->dismiss_alarm(substr($id, 4), $event['snooze']);
         }
         break;
 
       case "changelog":
         $data = $this->driver->get_event_changelog($event);
         if (is_array($data) && !empty($data)) {
           $lib = $this->lib;
           $dtformat = $this->rc->config->get('date_format') . ' ' . $this->rc->config->get('time_format');
           array_walk($data, function(&$change) use ($lib, $dtformat) {
             if ($change['date']) {
               $dt = $lib->adjust_timezone($change['date']);
               if ($dt instanceof DateTime)
                 $change['date'] = $this->rc->format_date($dt, $dtformat, false);
             }
           });
           $this->rc->output->command('plugin.render_event_changelog', $data);
         }
         else {
           $this->rc->output->command('plugin.render_event_changelog', false);
         }
         $got_msg = true;
         $reload = false;
         break;
 
       case "diff":
         $data = $this->driver->get_event_diff($event, $event['rev1'], $event['rev2']);
         if (is_array($data)) {
           // convert some properties, similar to self::_client_event()
           $lib = $this->lib;
           array_walk($data['changes'], function(&$change, $i) use ($event, $lib) {
             // convert date cols
             foreach (array('start','end','created','changed') as $col) {
               if ($change['property'] == $col) {
                 $change['old'] = $lib->adjust_timezone($change['old'], strlen($change['old']) == 10)->format('c');
                 $change['new'] = $lib->adjust_timezone($change['new'], strlen($change['new']) == 10)->format('c');
               }
             }
             // create textual representation for alarms and recurrence
             if ($change['property'] == 'alarms') {
               if (is_array($change['old']))
                 $change['old_'] = libcalendaring::alarm_text($change['old']);
               if (is_array($change['new']))
                 $change['new_'] = libcalendaring::alarm_text(array_merge((array)$change['old'], $change['new']));
             }
             if ($change['property'] == 'recurrence') {
               if (is_array($change['old']))
                 $change['old_'] = $lib->recurrence_text($change['old']);
               if (is_array($change['new']))
                 $change['new_'] = $lib->recurrence_text(array_merge((array)$change['old'], $change['new']));
             }
             if ($change['property'] == 'attachments') {
               if (is_array($change['old']))
                 $change['old']['classname'] = rcube_utils::file2class($change['old']['mimetype'], $change['old']['name']);
               if (is_array($change['new']))
                 $change['new']['classname'] = rcube_utils::file2class($change['new']['mimetype'], $change['new']['name']);
             }
             // compute a nice diff of description texts
             if ($change['property'] == 'description') {
               $change['diff_'] = libkolab::html_diff($change['old'], $change['new']);
             }
           });
           $this->rc->output->command('plugin.event_show_diff', $data);
         }
         else {
           $this->rc->output->command('display_message', $this->gettext('objectdiffnotavailable'), 'error');
         }
         $got_msg = true;
         $reload = false;
         break;
 
       case "show":
         if ($event = $this->driver->get_event_revison($event, $event['rev'])) {
           $this->rc->output->command('plugin.event_show_revision', $this->_client_event($event));
         }
         else {
           $this->rc->output->command('display_message', $this->gettext('objectnotfound'), 'error');
         }
         $got_msg = true;
         $reload = false;
         break;
 
       case "restore":
         if ($success = $this->driver->restore_event_revision($event, $event['rev'])) {
           $_event = $this->driver->get_event($event);
           $reload = $_event['recurrence'] ? 2 : 1;
           $this->rc->output->command('display_message', $this->gettext(array('name' => 'objectrestoresuccess', 'vars' => array('rev' => $event['rev']))), 'confirmation');
           $this->rc->output->command('plugin.close_history_dialog');
         }
         else {
           $this->rc->output->command('display_message', $this->gettext('objectrestoreerror'), 'error');
           $reload = 0;
         }
         $got_msg = true;
         break;
     }
 
     // show confirmation/error message
     if (!$got_msg) {
       if ($success)
         $this->rc->output->show_message('successfullysaved', 'confirmation');
       else
         $this->rc->output->show_message('calendar.errorsaving', 'error');
     }
 
     // unlock client
     $this->rc->output->command('plugin.unlock_saving', $success);
 
     // update event object on the client or trigger a complete refresh if too complicated
     if ($reload && empty($_REQUEST['_framed'])) {
       $args = array('source' => $event['calendar']);
       if ($reload > 1)
         $args['refetch'] = true;
       else if ($success && $action != 'remove')
         $args['update'] = $this->_client_event($this->driver->get_event($event), true);
       $this->rc->output->command('plugin.refresh_calendar', $args);
     }
   }
 
   /**
    * Helper method sending iTip notifications after successful event updates
    */
   private function event_save_success(&$event, $old, $action, $success)
   {
     // $success is a new event ID
     if ($success !== true) {
       // send update notification on the main event
       if ($event['_savemode'] == 'future' && $event['_notify'] && $old['attendees'] && $old['recurrence_id']) {
         $master = $this->driver->get_event(array('id' => $old['recurrence_id'], 'calendar' => $old['calendar']), 0, true);
         unset($master['_instance'], $master['recurrence_date']);
 
         $sent = $this->notify_attendees($master, null, $action, $event['_comment'], false);
         if ($sent < 0)
           $this->rc->output->show_message('calendar.errornotifying', 'error');
 
         $event['attendees'] = $master['attendees'];  // this tricks us into the next if clause
       }
 
       // delete old reference if saved as new
       if ($event['_savemode'] == 'future' || $event['_savemode'] == 'new') {
         $old = null;
       }
 
       $event['id'] = $success;
       $event['_savemode'] = 'all';
     }
 
     // send out notifications
     if ($event['_notify'] && ($event['attendees'] || $old['attendees'])) {
       $_savemode = $event['_savemode'];
 
       // send notification for the main event when savemode is 'all'
       if ($action != 'remove' && $_savemode == 'all' && ($event['recurrence_id'] || $old['recurrence_id'] || ($old && $old['id'] != $event['id']))) {
         $event['id'] = $event['recurrence_id'] ?: ($old['recurrence_id'] ?: $old['id']);
         $event = $this->driver->get_event($event, 0, true);
         unset($event['_instance'], $event['recurrence_date']);
       }
       else {
         // make sure we have the complete record
         $event = $action == 'remove' ? $old : $this->driver->get_event($event, 0, true);
       }
 
       $event['_savemode'] = $_savemode;
 
       if ($old) {
         $old['thisandfuture'] = $_savemode == 'future';
       }
 
       // only notify if data really changed (TODO: do diff check on client already)
       if (!$old || $action == 'remove' || self::event_diff($event, $old)) {
         $sent = $this->notify_attendees($event, $old, $action, $event['_comment']);
         if ($sent > 0)
           $this->rc->output->show_message('calendar.itipsendsuccess', 'confirmation');
         else if ($sent < 0)
           $this->rc->output->show_message('calendar.errornotifying', 'error');
       }
     }
   }
 
   /**
    * Handler for load-requests from fullcalendar
    * This will return pure JSON formatted output
    */
   function load_events()
   {
     $start = rcube_utils::get_input_value('start', rcube_utils::INPUT_GET);
     $end   = rcube_utils::get_input_value('end', rcube_utils::INPUT_GET);
     $query = rcube_utils::get_input_value('q', rcube_utils::INPUT_GET);
     $sorce = rcube_utils::get_input_value('source', rcube_utils::INPUT_GET);
 
     if (!is_numeric($start) || strpos($start, 'T')) {
       $start = new DateTime($start, $this->timezone);
       $start = $start->getTimestamp();
     }
     if (!is_numeric($end) || strpos($end, 'T')) {
       $end = new DateTime($end, $this->timezone);
       $end = $end->getTimestamp();
     }
 
     $events = $this->driver->load_events($start, $end, $query, $source);
     echo $this->encode($events, !empty($query));
     exit;
   }
 
   /**
    * Handler for requests fetching event counts for calendars
    */
   public function count_events()
   {
     // don't update session on these requests (avoiding race conditions)
     $this->rc->session->nowrite = true;
 
     $start = rcube_utils::get_input_value('start', rcube_utils::INPUT_GET);
     if (!$start) {
       $start = new DateTime('today 00:00:00', $this->timezone);
       $start = $start->format('U');
     }
 
     $counts = $this->driver->count_events(
       rcube_utils::get_input_value('source', rcube_utils::INPUT_GET),
       $start,
       rcube_utils::get_input_value('end', rcube_utils::INPUT_GET)
     );
 
     $this->rc->output->command('plugin.update_counts', array('counts' => $counts));
   }
 
   /**
    * Load event data from an iTip message attachment
    */
   public function itip_events($msgref)
   {
     $path = explode('/', $msgref);
     $msg = array_pop($path);
     $mbox = join('/', $path);
     list($uid, $mime_id) = explode('#', $msg);
     $events = array();
 
     if ($event = $this->lib->mail_get_itip_object($mbox, $uid, $mime_id, 'event')) {
       $partstat = 'NEEDS-ACTION';
 /*
       $user_emails = $this->lib->get_user_emails();
       foreach ($event['attendees'] as $attendee) {
         if (in_array($attendee['email'], $user_emails)) {
           $partstat = $attendee['status'];
           break;
         }
       }
 */
       $event['id'] = $event['uid'];
       $event['temporary'] = true;
       $event['readonly'] = true;
       $event['calendar'] = '--invitation--itip';
       $event['className'] = 'fc-invitation-' . strtolower($partstat);
       $event['_mbox'] = $mbox;
       $event['_uid']  = $uid;
       $event['_part'] = $mime_id;
 
       $events[] = $this->_client_event($event, true);
 
       // add recurring instances
       if (!empty($event['recurrence'])) {
         foreach ($this->driver->get_recurring_events($event, $event['start']) as $recurring) {
           $recurring['temporary'] = true;
           $recurring['readonly'] = true;
           $recurring['calendar'] = '--invitation--itip';
           $events[] = $this->_client_event($recurring, true);
         }
       }
     }
 
     return $events;
   }
 
   /**
    * Handler for keep-alive requests
    * This will check for updated data in active calendars and sync them to the client
    */
   public function refresh($attr)
   {
      // refresh the entire calendar every 10th time to also sync deleted events
     if (rand(0,10) == 10) {
         $this->rc->output->command('plugin.refresh_calendar', array('refetch' => true));
         return;
     }
 
     $counts = array();
 
     foreach ($this->driver->list_calendars(calendar_driver::FILTER_ACTIVE) as $cal) {
       $events = $this->driver->load_events(
         rcube_utils::get_input_value('start', rcube_utils::INPUT_GPC),
         rcube_utils::get_input_value('end', rcube_utils::INPUT_GPC),
         rcube_utils::get_input_value('q', rcube_utils::INPUT_GPC),
         $cal['id'],
         1,
         $attr['last']
       );
 
       foreach ($events as $event) {
         $this->rc->output->command('plugin.refresh_calendar',
           array('source' => $cal['id'], 'update' => $this->_client_event($event)));
       }
 
       // refresh count for this calendar
       if ($cal['counts']) {
         $today = new DateTime('today 00:00:00', $this->timezone);
         $counts += $this->driver->count_events($cal['id'], $today->format('U'));
       }
     }
 
     if (!empty($counts)) {
       $this->rc->output->command('plugin.update_counts', array('counts' => $counts));
     }
   }
 
   /**
    * Handler for pending_alarms plugin hook triggered by the calendar module on keep-alive requests.
    * This will check for pending notifications and pass them to the client
    */
   public function pending_alarms($p)
   {
     $this->load_driver();
     $time = $p['time'] ?: time();
     if ($alarms = $this->driver->pending_alarms($time)) {
       foreach ($alarms as $alarm) {
         $alarm['id'] = 'cal:' . $alarm['id'];  // prefix ID with cal:
         $p['alarms'][] = $alarm;
       }
     }
 
     // get alarms for birthdays calendar
     if ($this->rc->config->get('calendar_contact_birthdays') && $this->rc->config->get('calendar_birthdays_alarm_type') == 'DISPLAY') {
       $cache = $this->rc->get_cache('calendar.birthdayalarms', 'db');
 
       foreach ($this->driver->load_birthday_events($time, $time + 86400 * 60) as $e) {
         $alarm = libcalendaring::get_next_alarm($e);
 
         // overwrite alarm time with snooze value (or null if dismissed)
         if ($dismissed = $cache->get($e['id']))
           $alarm['time'] = $dismissed['notifyat'];
 
         // add to list if alarm is set
         if ($alarm && $alarm['time'] && $alarm['time'] <= $time) {
           $e['id'] = 'cal:bday:' . $e['id'];
           $e['notifyat'] = $alarm['time'];
           $p['alarms'][] = $e;
         }
       }
     }
 
     return $p;
   }
 
   /**
    * Handler for alarm dismiss hook triggered by libcalendaring
    */
   public function dismiss_alarms($p)
   {
       $this->load_driver();
       foreach ((array)$p['ids'] as $id) {
           if (strpos($id, 'cal:bday:') === 0) {
               $p['success'] |= $this->driver->dismiss_birthday_alarm(substr($id, 9), $p['snooze']);
           }
           else if (strpos($id, 'cal:') === 0) {
               $p['success'] |= $this->driver->dismiss_alarm(substr($id, 4), $p['snooze']);
           }
       }
 
       return $p;
   }
 
   /**
    * Handler for check-recent requests which are accidentally sent to calendar
    */
   function check_recent()
   {
     // NOP
     $this->rc->output->send();
   }
 
   /**
    * Hook triggered when a contact is saved
    */
   function contact_update($p)
   {
     // clear birthdays calendar cache
     if (!empty($p['record']['birthday'])) {
       $cache = $this->rc->get_cache('calendar.birthdays', 'db');
       $cache->remove();
     }
   }
 
   /**
    *
    */
   function import_events()
   {
     // Upload progress update
     if (!empty($_GET['_progress'])) {
       $this->rc->upload_progress();
     }
 
     @set_time_limit(0);
 
     // process uploaded file if there is no error
     $err = $_FILES['_data']['error'];
 
     if (!$err && $_FILES['_data']['tmp_name']) {
       $calendar   = rcube_utils::get_input_value('calendar', rcube_utils::INPUT_GPC);
       $rangestart = $_REQUEST['_range'] ? date_create("now -" . intval($_REQUEST['_range']) . " months") : 0;
 
       // extract zip file
       if ($_FILES['_data']['type'] == 'application/zip') {
         $count = 0;
         if (class_exists('ZipArchive', false)) {
           $zip = new ZipArchive();
           if ($zip->open($_FILES['_data']['tmp_name'])) {
             $randname = uniqid('zip-' . session_id(), true);
             $tmpdir = slashify($this->rc->config->get('temp_dir', sys_get_temp_dir())) . $randname;
             mkdir($tmpdir, 0700);
 
             // extract each ical file from the archive and import it
             for ($i = 0; $i < $zip->numFiles; $i++) { 
               $filename = $zip->getNameIndex($i);
               if (preg_match('/\.ics$/i', $filename)) {
                 $tmpfile = $tmpdir . '/' . basename($filename);
                 if (copy('zip://' . $_FILES['_data']['tmp_name'] . '#'.$filename, $tmpfile)) {
                   $count += $this->import_from_file($tmpfile, $calendar, $rangestart, $errors);
                   unlink($tmpfile);
                 }
               }
             }
 
             rmdir($tmpdir);
             $zip->close();
           }
           else {
             $errors = 1;
             $msg = 'Failed to open zip file.';
           }
         }
         else {
           $errors = 1;
           $msg = 'Zip files are not supported for import.';
         }
       }
       else {
         // attempt to import teh uploaded file directly
         $count = $this->import_from_file($_FILES['_data']['tmp_name'], $calendar, $rangestart, $errors);
       }
 
       if ($count) {
         $this->rc->output->command('display_message', $this->gettext(array('name' => 'importsuccess', 'vars' => array('nr' => $count))), 'confirmation');
         $this->rc->output->command('plugin.import_success', array('source' => $calendar, 'refetch' => true));
       }
       else if (!$errors) {
         $this->rc->output->command('display_message', $this->gettext('importnone'), 'notice');
         $this->rc->output->command('plugin.import_success', array('source' => $calendar));
       }
       else {
         $this->rc->output->command('plugin.import_error', array('message' => $this->gettext('importerror') . ($msg ? ': ' . $msg : '')));
       }
     }
     else {
       if ($err == UPLOAD_ERR_INI_SIZE || $err == UPLOAD_ERR_FORM_SIZE) {
         $msg = $this->rc->gettext(array('name' => 'filesizeerror', 'vars' => array(
             'size' => $this->rc->show_bytes(parse_bytes(ini_get('upload_max_filesize'))))));
       }
       else {
         $msg = $this->rc->gettext('fileuploaderror');
       }
 
       $this->rc->output->command('plugin.import_error', array('message' => $msg));
     }
 
     $this->rc->output->send('iframe');
   }
 
   /**
    * Helper function to parse and import a single .ics file
    */
   private function import_from_file($filepath, $calendar, $rangestart, &$errors)
   {
     $user_email = $this->rc->user->get_username();
 
     $ical = $this->get_ical();
     $errors = !$ical->fopen($filepath);
     $count = $i = 0;
     foreach ($ical as $event) {
       // keep the browser connection alive on long import jobs
       if (++$i > 100 && $i % 100 == 0) {
           echo "<!-- -->";
           ob_flush();
       }
 
       // TODO: correctly handle recurring events which start before $rangestart
       if ($event['end'] < $rangestart && (!$event['recurrence'] || ($event['recurrence']['until'] && $event['recurrence']['until'] < $rangestart)))
         continue;
 
       $event['_owner'] = $user_email;
       $event['calendar'] = $calendar;
       if ($this->driver->new_event($event)) {
         $count++;
       }
       else {
         $errors++;
       }
     }
 
     return $count;
   }
 
 
   /**
    * Construct the ics file for exporting events to iCalendar format;
    */
   function export_events($terminate = true)
   {
     $start = rcube_utils::get_input_value('start', rcube_utils::INPUT_GET);
     $end   = rcube_utils::get_input_value('end', rcube_utils::INPUT_GET);
 
     if (!isset($start))
       $start = 'today -1 year';
     if (!is_numeric($start))
       $start = strtotime($start . ' 00:00:00');
     if (!$end)
       $end = 'today +10 years';
     if (!is_numeric($end))
       $end = strtotime($end . ' 23:59:59');
 
     $event_id    = rcube_utils::get_input_value('id', rcube_utils::INPUT_GET);
     $attachments = rcube_utils::get_input_value('attachments', rcube_utils::INPUT_GET);
     $calid = $filename = rcube_utils::get_input_value('source', rcube_utils::INPUT_GET);
 
     $calendars = $this->driver->list_calendars();
     $events = array();
 
     if ($calendars[$calid]) {
       $filename = $calendars[$calid]['name'] ? $calendars[$calid]['name'] : $calid;
       $filename = asciiwords(html_entity_decode($filename));  // to 7bit ascii
       if (!empty($event_id)) {
         if ($event = $this->driver->get_event(array('calendar' => $calid, 'id' => $event_id), 0, true)) {
           if ($event['recurrence_id']) {
             $event = $this->driver->get_event(array('calendar' => $calid, 'id' => $event['recurrence_id']), 0, true);
           }
           $events = array($event);
           $filename = asciiwords($event['title']);
           if (empty($filename))
             $filename = 'event';
         }
       }
       else {
          $events = $this->driver->load_events($start, $end, null, $calid, 0);
          if (empty($filename))
            $filename = $calid;
       }
     }
 
     header("Content-Type: text/calendar");
     header("Content-Disposition: inline; filename=".$filename.'.ics');
 
     $this->get_ical()->export($events, '', true, $attachments ? array($this->driver, 'get_attachment_body') : null);
 
     if ($terminate)
       exit;
   }
 
 
   /**
    * Handler for iCal feed requests
    */
   function ical_feed_export()
   {
     $session_exists = !empty($_SESSION['user_id']);
 
     // process HTTP auth info
     if (!empty($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
       $_POST['_user'] = $_SERVER['PHP_AUTH_USER']; // used for rcmail::autoselect_host()
       $auth = $this->rc->plugins->exec_hook('authenticate', array(
         'host' => $this->rc->autoselect_host(),
         'user' => trim($_SERVER['PHP_AUTH_USER']),
         'pass' => $_SERVER['PHP_AUTH_PW'],
         'cookiecheck' => true,
         'valid' => true,
       ));
       if ($auth['valid'] && !$auth['abort'])
         $this->rc->login($auth['user'], $auth['pass'], $auth['host']);
     }
 
     // require HTTP auth
     if (empty($_SESSION['user_id'])) {
       header('WWW-Authenticate: Basic realm="Roundcube Calendar"');
       header('HTTP/1.0 401 Unauthorized');
       exit;
     }
 
     // decode calendar feed hash
     $format = 'ics';
     $calhash = rcube_utils::get_input_value('_cal', rcube_utils::INPUT_GET);
     if (preg_match(($suff_regex = '/\.([a-z0-9]{3,5})$/i'), $calhash, $m)) {
       $format = strtolower($m[1]);
       $calhash = preg_replace($suff_regex, '', $calhash);
     }
 
     if (!strpos($calhash, ':'))
       $calhash = base64_decode($calhash);
 
     list($user, $_GET['source']) = explode(':', $calhash, 2);
 
     // sanity check user
     if ($this->rc->user->get_username() == $user) {
       $this->setup();
       $this->load_driver();
       $this->export_events(false);
     }
     else {
       header('HTTP/1.0 404 Not Found');
     }
 
     // don't save session data
     if (!$session_exists)
       session_destroy();
     exit;
   }
 
   /**
    *
    */
   function load_settings()
   {
     $this->lib->load_settings();
     $this->defaults += $this->lib->defaults;
 
     $settings = array();
 
     // configuration
     $settings['default_calendar'] = $this->rc->config->get('calendar_default_calendar');
     $settings['default_view'] = (string)$this->rc->config->get('calendar_default_view', $this->defaults['calendar_default_view']);
     $settings['timeslots'] = (int)$this->rc->config->get('calendar_timeslots', $this->defaults['calendar_timeslots']);
     $settings['first_day'] = (int)$this->rc->config->get('calendar_first_day', $this->defaults['calendar_first_day']);
     $settings['first_hour'] = (int)$this->rc->config->get('calendar_first_hour', $this->defaults['calendar_first_hour']);
     $settings['work_start'] = (int)$this->rc->config->get('calendar_work_start', $this->defaults['calendar_work_start']);
     $settings['work_end'] = (int)$this->rc->config->get('calendar_work_end', $this->defaults['calendar_work_end']);
     $settings['agenda_range'] = (int)$this->rc->config->get('calendar_agenda_range', $this->defaults['calendar_agenda_range']);
     $settings['agenda_sections'] = $this->rc->config->get('calendar_agenda_sections', $this->defaults['calendar_agenda_sections']);
     $settings['event_coloring'] = (int)$this->rc->config->get('calendar_event_coloring', $this->defaults['calendar_event_coloring']);
     $settings['time_indicator'] = (int)$this->rc->config->get('calendar_time_indicator', $this->defaults['calendar_time_indicator']);
     $settings['invite_shared'] = (int)$this->rc->config->get('calendar_allow_invite_shared', $this->defaults['calendar_allow_invite_shared']);
     $settings['invitation_calendars'] = (bool)$this->rc->config->get('kolab_invitation_calendars', false);
     $settings['itip_notify'] = (int)$this->rc->config->get('calendar_itip_send_option', $this->defaults['calendar_itip_send_option']);
     $settings['show_weekno'] = (int)$this->rc->config->get('calendar_show_weekno', $this->defaults['calendar_show_weekno']);
 
     // get user identity to create default attendee
     if ($this->ui->screen == 'calendar') {
       foreach ($this->rc->user->list_emails() as $rec) {
         if (!$identity)
           $identity = $rec;
         $identity['emails'][] = $rec['email'];
         $settings['identities'][$rec['identity_id']] = $rec['email'];
       }
       $identity['emails'][] = $this->rc->user->get_username();
       $settings['identity'] = array('name' => $identity['name'], 'email' => strtolower($identity['email']), 'emails' => ';' . strtolower(join(';', $identity['emails'])));
     }
 
     // freebusy token authentication URL
     if (($url = $this->rc->config->get('calendar_freebusy_session_auth_url'))
       && ($uniqueid = $this->rc->config->get('kolab_uniqueid'))
     ) {
       if ($url === true) $url = '/freebusy';
       $url = rtrim(rcube_utils::resolve_url($url), '/ ');
       $url .= '/' . urlencode($this->rc->get_user_name());
       $url .= '/' . urlencode($uniqueid);
 
       $settings['freebusy_url'] = $url;
     }
 
     return $settings;
   }
 
   /**
    * Encode events as JSON
    *
    * @param  array  Events as array
    * @param  boolean Add CSS class names according to calendar and categories
    * @return string JSON encoded events
    */
   function encode($events, $addcss = false)
   {
     $json = array();
     foreach ($events as $event) {
       $json[] = $this->_client_event($event, $addcss);
     }
     return rcube_output::json_serialize($json);
   }
 
   /**
    * Convert an event object to be used on the client
    */
   private function _client_event($event, $addcss = false)
   {
     // compose a human readable strings for alarms_text and recurrence_text
     if ($event['valarms']) {
       $event['alarms_text'] = libcalendaring::alarms_text($event['valarms']);
       $event['valarms'] = libcalendaring::to_client_alarms($event['valarms']);
     }
     if ($event['recurrence']) {
       $event['recurrence_text'] = $this->lib->recurrence_text($event['recurrence']);
       $event['recurrence'] = $this->lib->to_client_recurrence($event['recurrence'], $event['allday']);
       unset($event['recurrence_date']);
     }
 
     foreach ((array)$event['attachments'] as $k => $attachment) {
       $event['attachments'][$k]['classname'] = rcube_utils::file2class($attachment['mimetype'], $attachment['name']);
 
       unset($event['attachments'][$k]['data'], $event['attachments'][$k]['content']);
 
       if (!$attachment['id']) {
         $event['attachments'][$k]['id'] = $k;
       }
     }
 
     // convert link URIs references into structs
     if (array_key_exists('links', $event)) {
         foreach ((array) $event['links'] as $i => $link) {
             if (strpos($link, 'imap://') === 0 && ($msgref = $this->driver->get_message_reference($link))) {
                 $event['links'][$i] = $msgref;
             }
         }
     }
 
     // check for organizer in attendees list
     $organizer = null;
     foreach ((array)$event['attendees'] as $i => $attendee) {
       if ($attendee['role'] == 'ORGANIZER') {
         $organizer = $attendee;
       }
       if ($attendee['status'] == 'DELEGATED' && $attendee['rsvp'] == false) {
         $event['attendees'][$i]['noreply'] = true;
       }
       else {
         unset($event['attendees'][$i]['noreply']);
       }
     }
 
     if ($organizer === null && !empty($event['organizer'])) {
       $organizer = $event['organizer'];
       $organizer['role'] = 'ORGANIZER';
       if (!is_array($event['attendees']))
         $event['attendees'] = array();
       array_unshift($event['attendees'], $organizer);
     }
 
     // Convert HTML description into plain text
     if ($this->is_html($event)) {
       $h2t = new rcube_html2text($event['description'], false, true, 0);
       $event['description'] = trim($h2t->get_text());
     }
 
     // mapping url => vurl, allday => allDay because of the fullcalendar client script
     $event['vurl'] = $event['url'];
     $event['allDay'] = !empty($event['allday']);
     unset($event['url']);
     unset($event['allday']);
 
     $event['className'] = $event['className'] ? explode(' ', $event['className']) : array();
     if ($addcss) {
         $event['className'][] = 'fc-event-cal-' . asciiwords($event['calendar'], true);
     }
 
     if ($event['allDay']) {
         $event['end'] = $event['end']->add(new DateInterval('P1D'));
     }
 
     return array(
       '_id'   => $event['calendar'] . ':' . $event['id'],  // unique identifier for fullcalendar
       'start' => $this->lib->adjust_timezone($event['start'], $event['allDay'])->format('c'),
       'end'   => $this->lib->adjust_timezone($event['end'], $event['allDay'])->format('c'),
       // 'changed' might be empty for event recurrences (Bug #2185)
       'changed' => $event['changed'] ? $this->lib->adjust_timezone($event['changed'])->format('c') : null,
       'created' => $event['created'] ? $this->lib->adjust_timezone($event['created'])->format('c') : null,
       'title'       => strval($event['title']),
       'description' => strval($event['description']),
       'location'    => strval($event['location']),
     ) + $event;
   }
 
 
   /**
    * Generate a unique identifier for an event
    */
   public function generate_uid()
   {
     return strtoupper(md5(time() . uniqid(rand())) . '-' . substr(md5($this->rc->user->get_username()), 0, 16));
   }
 
 
   /**
    * TEMPORARY: generate random event data for testing
    * Create events by opening http://<roundcubeurl>/?_task=calendar&_action=randomdata&_num=500&_date=2014-08-01&_dev=120
    */
   public function generate_randomdata()
   {
     @set_time_limit(0);
 
     $num   = $_REQUEST['_num'] ? intval($_REQUEST['_num']) : 100;
     $date  = $_REQUEST['_date'] ?: 'now';
     $dev   = $_REQUEST['_dev'] ?: 30;
     $cats  = array_keys($this->driver->list_categories());
     $cals  = $this->driver->list_calendars(calendar_driver::FILTER_ACTIVE);
     $count = 0;
 
     while ($count++ < $num) {
       $spread = intval($dev) * 86400; // days
       $refdate = strtotime($date);
       $start = round(($refdate + rand(-$spread, $spread)) / 600) * 600;
       $duration = round(rand(30, 360) / 30) * 30 * 60;
       $allday = rand(0,20) > 18;
       $alarm = rand(-30,12) * 5;
       $fb = rand(0,2);
       
       if (date('G', $start) > 23)
         $start -= 3600;
       
       if ($allday) {
         $start = strtotime(date('Y-m-d 00:00:00', $start));
         $duration = 86399;
       }
       
       $title = '';
       $len = rand(2, 12);
       $words = explode(" ", "The Hough transform is named after Paul Hough who patented the method in 1962. It is a technique which can be used to isolate features of a particular shape within an image. Because it requires that the desired features be specified in some parametric form, the classical Hough transform is most commonly used for the de- tection of regular curves such as lines, circles, ellipses, etc. A generalized Hough transform can be employed in applications where a simple analytic description of a feature(s) is not possible. Due to the computational complexity of the generalized Hough algorithm, we restrict the main focus of this discussion to the classical Hough transform. Despite its domain restrictions, the classical Hough transform (hereafter referred to without the classical prefix ) retains many applications, as most manufac- tured parts (and many anatomical parts investigated in medical imagery) contain feature boundaries which can be described by regular curves. The main advantage of the Hough transform technique is that it is tolerant of gaps in feature boundary descriptions and is relatively unaffected by image noise.");
 //      $chars = "!# abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890";
       for ($i = 0; $i < $len; $i++)
         $title .= $words[rand(0,count($words)-1)] . " ";
       
       $this->driver->new_event(array(
         'uid' => $this->generate_uid(),
         'start' => new DateTime('@'.$start),
         'end' => new DateTime('@'.($start + $duration)),
         'allday' => $allday,
         'title' => rtrim($title),
         'free_busy' => $fb == 2 ? 'outofoffice' : ($fb ? 'busy' : 'free'),
         'categories' => $cats[array_rand($cats)],
         'calendar' => array_rand($cals),
         'alarms' => $alarm > 0 ? "-{$alarm}M:DISPLAY" : '',
         'priority' => rand(0,9),
       ));
     }
     
     $this->rc->output->redirect('');
   }
 
   /**
    * Handler for attachments upload
    */
   public function attachment_upload()
   {
     $handler = new kolab_attachments_handler();
     $handler->attachment_upload(self::SESSION_KEY, 'cal-');
   }
 
   /**
    * Handler for attachments download/displaying
    */
   public function attachment_get()
   {
     $handler = new kolab_attachments_handler();
 
     // show loading page
     if (!empty($_GET['_preload'])) {
         return $handler->attachment_loading_page();
     }
 
     $event_id = rcube_utils::get_input_value('_event', rcube_utils::INPUT_GPC);
     $calendar = rcube_utils::get_input_value('_cal', rcube_utils::INPUT_GPC);
     $id       = rcube_utils::get_input_value('_id', rcube_utils::INPUT_GPC);
     $rev      = rcube_utils::get_input_value('_rev', rcube_utils::INPUT_GPC);
 
     $event = array('id' => $event_id, 'calendar' => $calendar, 'rev' => $rev);
 
     if ($calendar == '--invitation--itip') {
         $uid  = rcube_utils::get_input_value('_uid', rcube_utils::INPUT_GPC);
         $part = rcube_utils::get_input_value('_part', rcube_utils::INPUT_GPC);
         $mbox = rcube_utils::get_input_value('_mbox', rcube_utils::INPUT_GPC);
 
         $event      = $this->lib->mail_get_itip_object($mbox, $uid, $part, 'event');
         $attachment = $event['attachments'][$id];
         $attachment['body'] = &$attachment['data'];
     }
     else {
         $attachment = $this->driver->get_attachment($id, $event);
     }
 
     // show part page
     if (!empty($_GET['_frame'])) {
         $handler->attachment_page($attachment);
     }
     // deliver attachment content
     else if ($attachment) {
         if ($calendar != '--invitation--itip') {
             $attachment['body'] = $this->driver->get_attachment_body($id, $event);
         }
 
         $handler->attachment_get($attachment);
     }
 
     // if we arrive here, the requested part was not found
     header('HTTP/1.1 404 Not Found');
     exit;
   }
 
   /**
    * Determine whether the given event description is HTML formatted
    */
   private function is_html($event)
   {
       // check for opening and closing <html> or <body> tags
       return (preg_match('/<(html|body)(\s+[a-z]|>)/', $event['description'], $m) && strpos($event['description'], '</'.$m[1].'>') > 0);
   }
 
   /**
    * Prepares new/edited event properties before save
    */
   private function write_preprocess(&$event, $action)
   {
     // Remove double timezone specification (T2313)
     $event['start'] = preg_replace('/\s*\(.*\)/', '', $event['start']);
     $event['end']   = preg_replace('/\s*\(.*\)/', '', $event['end']);
 
     // convert dates into DateTime objects in user's current timezone
     $event['start']  = new DateTime($event['start'], $this->timezone);
     $event['end']    = new DateTime($event['end'], $this->timezone);
     $event['allday'] = (bool) (isset($event['allDay']) ? $event['allDay'] : $event['allday']);
 
     if ($event['allday']) {
     
     }
 
     // start/end is all we need for 'move' action (#1480)
     if ($action == 'move') {
       return true;
     }
 
     // convert the submitted recurrence settings
     if (is_array($event['recurrence'])) {
       $event['recurrence'] = $this->lib->from_client_recurrence($event['recurrence'], $event['start']);
 
       // align start date with the first occurrence
       if (!empty($event['recurrence']) && !empty($event['syncstart'])
         && (empty($event['_savemode']) || $event['_savemode'] == 'all')
       ) {
         $next = $this->find_first_occurrence($event);
 
         if (!$next) {
           $this->rc->output->show_message('calendar.recurrenceerror', 'error');
           return false;
         }
         else if ($event['start'] != $next) {
           $diff = $event['start']->diff($event['end'], true);
 
           $event['start'] = $next;
           $event['end']   = clone $next;
           $event['end']->add($diff);
         }
       }
     }
 
     // convert the submitted alarm values
     if ($event['valarms']) {
       $event['valarms'] = libcalendaring::from_client_alarms($event['valarms']);
     }
 
     $attachments = array();
     $eventid     = 'cal-'.$event['id'];
 
     if (is_array($_SESSION[self::SESSION_KEY]) && $_SESSION[self::SESSION_KEY]['id'] == $eventid) {
       if (!empty($_SESSION[self::SESSION_KEY]['attachments'])) {
         foreach ($_SESSION[self::SESSION_KEY]['attachments'] as $id => $attachment) {
           if (is_array($event['attachments']) && in_array($id, $event['attachments'])) {
             $attachments[$id] = $this->rc->plugins->exec_hook('attachment_get', $attachment);
           }
         }
       }
     }
 
     $event['attachments'] = $attachments;
 
     // convert link references into simple URIs
     if (array_key_exists('links', $event)) {
       $event['links'] = array_map(function($link) {
           return is_array($link) ? $link['uri'] : strval($link);
         }, (array)$event['links']);
     }
 
     // check for organizer in attendees
     if ($action == 'new' || $action == 'edit') {
       if (!$event['attendees'])
         $event['attendees'] = array();
 
       $emails = $this->get_user_emails();
       $organizer = $owner = false;
       foreach ((array)$event['attendees'] as $i => $attendee) {
         if ($attendee['role'] == 'ORGANIZER')
           $organizer = $i;
         if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails))
           $owner = $i;
         if (!isset($attendee['rsvp']))
           $event['attendees'][$i]['rsvp'] = true;
         else if (is_string($attendee['rsvp']))
           $event['attendees'][$i]['rsvp'] = $attendee['rsvp'] == 'true' || $attendee['rsvp'] == '1';
       }
 
       if (!empty($event['_identity'])) {
         $identity = $this->rc->user->get_identity($event['_identity']);
       }
 
       // set new organizer identity
       if ($organizer !== false && $identity) {
         $event['attendees'][$organizer]['name'] = $identity['name'];
         $event['attendees'][$organizer]['email'] = $identity['email'];
       }
       // set owner as organizer if yet missing
       else if ($organizer === false && $owner !== false) {
         $event['attendees'][$owner]['role'] = 'ORGANIZER';
         unset($event['attendees'][$owner]['rsvp']);
       }
       // fallback to the selected identity
       else if ($organizer === false && $identity) {
         $event['attendees'][] = array(
           'role'  => 'ORGANIZER',
           'name'  => $identity['name'],
           'email' => $identity['email'],
         );
       }
     }
 
     // mapping url => vurl because of the fullcalendar client script
     if (array_key_exists('vurl', $event)) {
       $event['url'] = $event['vurl'];
       unset($event['vurl']);
     }
 
     return true;
   }
 
   /**
    * Releases some resources after successful event save
    */
   private function cleanup_event(&$event)
   {
     // remove temp. attachment files
     if (!empty($_SESSION[self::SESSION_KEY]) && ($eventid = $_SESSION[self::SESSION_KEY]['id'])) {
       $this->rc->plugins->exec_hook('attachments_cleanup', array('group' => $eventid));
       $this->rc->session->remove(self::SESSION_KEY);
     }
   }
 
   /**
    * Send out an invitation/notification to all event attendees
    */
   private function notify_attendees($event, $old, $action = 'edit', $comment = null, $rsvp = null)
   {
     if ($action == 'remove' || ($event['status'] == 'CANCELLED' && $old['status'] != $event['status'])) {
       $event['cancelled'] = true;
       $is_cancelled = true;
     }
 
     if ($rsvp === null)
       $rsvp = !$old || $event['sequence'] > $old['sequence'];
 
     $itip = $this->load_itip();
     $emails = $this->get_user_emails();
     $itip_notify = (int)$this->rc->config->get('calendar_itip_send_option', $this->defaults['calendar_itip_send_option']);
 
     // add comment to the iTip attachment
     $event['comment'] = $comment;
 
     // set a valid recurrence-id if this is a recurrence instance
     libcalendaring::identify_recurrence_instance($event);
 
     // compose multipart message using PEAR:Mail_Mime
     $method = $action == 'remove' ? 'CANCEL' : 'REQUEST';
     $message = $itip->compose_itip_message($event, $method, $rsvp);
 
     // list existing attendees from $old event
     $old_attendees = array();
     foreach ((array)$old['attendees'] as $attendee) {
       $old_attendees[] = $attendee['email'];
     }
 
     // send to every attendee
     $sent = 0; $current = array();
     foreach ((array)$event['attendees'] as $attendee) {
       $current[] = strtolower($attendee['email']);
       
       // skip myself for obvious reasons
       if (!$attendee['email'] || in_array(strtolower($attendee['email']), $emails))
         continue;
 
       // skip if notification is disabled for this attendee
       if ($attendee['noreply'] && $itip_notify & 2)
         continue;
 
       // skip if this attendee has delegated and set RSVP=FALSE
       if ($attendee['status'] == 'DELEGATED' && $attendee['rsvp'] === false)
         continue;
 
       // which template to use for mail text
       $is_new = !in_array($attendee['email'], $old_attendees);
       $is_rsvp = $is_new || $event['sequence'] > $old['sequence'];
       $bodytext = $is_cancelled ? 'eventcancelmailbody' : ($is_new ? 'invitationmailbody' : 'eventupdatemailbody');
       $subject  = $is_cancelled ? 'eventcancelsubject'  : ($is_new ? 'invitationsubject' : ($event['title'] ? 'eventupdatesubject':'eventupdatesubjectempty'));
 
       $event['comment'] = $comment;
 
       // finally send the message
       if ($itip->send_itip_message($event, $method, $attendee, $subject, $bodytext, $message, $is_rsvp))
         $sent++;
       else
         $sent = -100;
     }
 
     // TODO: on change of a recurring (main) event, also send updates to differing attendess of recurrence exceptions
 
     // send CANCEL message to removed attendees
     foreach ((array)$old['attendees'] as $attendee) {
       if ($attendee['role'] == 'ORGANIZER' || !$attendee['email'] || in_array(strtolower($attendee['email']), $current))
         continue;
 
       $vevent = $old;
       $vevent['cancelled'] = $is_cancelled;
       $vevent['attendees'] = array($attendee);
       $vevent['comment']   = $comment;
       if ($itip->send_itip_message($vevent, 'CANCEL', $attendee, 'eventcancelsubject', 'eventcancelmailbody'))
         $sent++;
       else
         $sent = -100;
     }
 
     return $sent;
   }
 
   /**
    * Echo simple free/busy status text for the given user and time range
    */
   public function freebusy_status()
   {
     $email = rcube_utils::get_input_value('email', rcube_utils::INPUT_GPC);
     $start = rcube_utils::get_input_value('start', rcube_utils::INPUT_GPC);
     $end   = rcube_utils::get_input_value('end', rcube_utils::INPUT_GPC);
 
     // convert dates into unix timestamps
     if (!empty($start) && !is_numeric($start)) {
       $dts = new DateTime($start, $this->timezone);
       $start = $dts->format('U');
     }
     if (!empty($end) && !is_numeric($end)) {
       $dte = new DateTime($end, $this->timezone);
       $end = $dte->format('U');
     }
     
     if (!$start) $start = time();
     if (!$end) $end = $start + 3600;
     
     $fbtypemap = array(calendar::FREEBUSY_UNKNOWN => 'UNKNOWN', calendar::FREEBUSY_FREE => 'FREE', calendar::FREEBUSY_BUSY => 'BUSY', calendar::FREEBUSY_TENTATIVE => 'TENTATIVE', calendar::FREEBUSY_OOF => 'OUT-OF-OFFICE');
     $status = 'UNKNOWN';
     
     // if the backend has free-busy information
     $fblist = $this->driver->get_freebusy_list($email, $start, $end);
 
     if (is_array($fblist)) {
       $status = 'FREE';
       
       foreach ($fblist as $slot) {
         list($from, $to, $type) = $slot;
         if ($from < $end && $to > $start) {
           $status = isset($type) && $fbtypemap[$type] ? $fbtypemap[$type] : 'BUSY';
           break;
         }
       }
     }
     
     // let this information be cached for 5min
     $this->rc->output->future_expire_header(300);
     
     echo $status;
     exit;
   }
   
   /**
    * Return a list of free/busy time slots within the given period
    * Echo data in JSON encoding
    */
   public function freebusy_times()
   {
     $email = rcube_utils::get_input_value('email', rcube_utils::INPUT_GPC);
     $start = rcube_utils::get_input_value('start', rcube_utils::INPUT_GPC);
     $end   = rcube_utils::get_input_value('end', rcube_utils::INPUT_GPC);
     $interval  = intval(rcube_utils::get_input_value('interval', rcube_utils::INPUT_GPC));
     $strformat = $interval > 60 ? 'Ymd' : 'YmdHis';
 
     // convert dates into unix timestamps
     if (!empty($start) && !is_numeric($start)) {
       $dts = rcube_utils::anytodatetime($start, $this->timezone);
       $start = $dts ? $dts->format('U') : null;
     }
     if (!empty($end) && !is_numeric($end)) {
       $dte = rcube_utils::anytodatetime($end, $this->timezone);
       $end = $dte ? $dte->format('U') : null;
     }
 
     if (!$start) $start = time();
     if (!$end)   $end = $start + 86400 * 30;
     if (!$interval) $interval = 60;  // 1 hour
     
     if (!$dte) {
       $dts = new DateTime('@'.$start);
       $dts->setTimezone($this->timezone);
     }
 
     $fblist = $this->driver->get_freebusy_list($email, $start, $end);
     $slots  = '';
 
     // prepare freebusy list before use (for better performance)
     if (is_array($fblist)) {
       foreach ($fblist as $idx => $slot) {
         list($from, $to, ) = $slot;
 
         // check for possible all-day times
         if (gmdate('His', $from) == '000000' && gmdate('His', $to) == '235959') {
           // shift into the user's timezone for sane matching
           $fblist[$idx][0] -= $this->gmt_offset;
           $fblist[$idx][1] -= $this->gmt_offset;
         }
       }
     }
 
     // build a list from $start till $end with blocks representing the fb-status
     for ($s = 0, $t = $start; $t <= $end; $s++) {
       $t_end = $t + $interval * 60;
       $dt = new DateTime('@'.$t);
       $dt->setTimezone($this->timezone);
 
       // determine attendee's status
       if (is_array($fblist)) {
         $status = self::FREEBUSY_FREE;
 
         foreach ($fblist as $slot) {
           list($from, $to, $type) = $slot;
 
           if ($from < $t_end && $to > $t) {
             $status = isset($type) ? $type : self::FREEBUSY_BUSY;
             if ($status == self::FREEBUSY_BUSY)  // can't get any worse :-)
               break;
           }
         }
       }
       else {
         $status = self::FREEBUSY_UNKNOWN;
       }
 
       // use most compact format, assume $status is one digit/character
       $slots .= $status;
       $t = $t_end;
     }
     
     $dte = new DateTime('@'.$t_end);
     $dte->setTimezone($this->timezone);
     
     // let this information be cached for 5min
     $this->rc->output->future_expire_header(300);
     
     echo rcube_output::json_serialize(array(
       'email' => $email,
       'start' => $dts->format('c'),
       'end'   => $dte->format('c'),
       'interval' => $interval,
       'slots' => $slots,
     ));
     exit;
   }
 
   /**
    * Handler for printing calendars
    */
   public function print_view()
   {
     $title = $this->gettext('print');
 
     $view = rcube_utils::get_input_value('view', rcube_utils::INPUT_GPC);
     if (!in_array($view, array('agendaWeek', 'agendaDay', 'month', 'table')))
       $view = 'agendaDay';
 
     $this->rc->output->set_env('view',$view);
 
     if ($date = rcube_utils::get_input_value('date', rcube_utils::INPUT_GPC))
       $this->rc->output->set_env('date', $date);
 
     if ($range = rcube_utils::get_input_value('range', rcube_utils::INPUT_GPC))
       $this->rc->output->set_env('listRange', intval($range));
 
     if (isset($_REQUEST['sections']))
       $this->rc->output->set_env('listSections', rcube_utils::get_input_value('sections', rcube_utils::INPUT_GPC));
 
     if ($search = rcube_utils::get_input_value('search', rcube_utils::INPUT_GPC)) {
       $this->rc->output->set_env('search', $search);
       $title .= ' "' . $search . '"';
     }
 
-    // Add CSS stylesheets to the page header
-    $skin_path = $this->local_skin_path();
-    $this->include_stylesheet($skin_path . '/fullcalendar.css');
-    $this->include_stylesheet($skin_path . '/print.css');
-
-    // Add JS files to the page header
-    $this->include_script('print.js');
-    $this->include_script('lib/js/moment.js');
-    $this->include_script('lib/js/fullcalendar.js');
+    // Add CSS and JS to the page
+    $this->ui->addCSS();
+    $this->ui->addJS();
 
     $this->register_handler('plugin.calendar_css', array($this->ui, 'calendar_css'));
     $this->register_handler('plugin.calendar_list', array($this->ui, 'calendar_list'));
 
     $this->rc->output->set_pagetitle($title);
-    $this->rc->output->send("calendar.print");
+    $this->rc->output->send('calendar.print');
   }
 
   /**
    * Compare two event objects and return differing properties
    *
    * @param array Event A
    * @param array Event B
    * @return array List of differing event properties
    */
   public static function event_diff($a, $b)
   {
     $diff = array();
     $ignore = array('changed' => 1, 'attachments' => 1);
     foreach (array_unique(array_merge(array_keys($a), array_keys($b))) as $key) {
       if (!$ignore[$key] && $key[0] != '_' && $a[$key] != $b[$key])
         $diff[] = $key;
     }
     
     // only compare number of attachments
     if (count($a['attachments']) != count($b['attachments']))
       $diff[] = 'attachments';
     
     return $diff;
   }
 
   /**
    * Update attendee properties on the given event object
    *
    * @param array The event object to be altered
    * @param array List of hash arrays each represeting an updated/added attendee
    */
   public static function merge_attendee_data(&$event, $attendees, $removed = null)
   {
     if (!empty($attendees) && !is_array($attendees[0])) {
       $attendees = array($attendees);
     }
 
     foreach ($attendees as $attendee) {
       $found = false;
 
       foreach ($event['attendees'] as $i => $candidate) {
         if ($candidate['email'] == $attendee['email']) {
           $event['attendees'][$i] = $attendee;
           $found = true;
           break;
         }
       }
 
       if (!$found) {
         $event['attendees'][] = $attendee;
       }
     }
 
     // filter out removed attendees
     if (!empty($removed)) {
       $event['attendees'] = array_filter($event['attendees'], function($attendee) use ($removed) {
         return !in_array($attendee['email'], $removed);
       });
     }
   }
 
 
   /****  Resource management functions  ****/
 
   /**
    * Getter for the configured implementation of the resource directory interface
    */
   private function resources_directory()
   {
     if (is_object($this->resources_dir)) {
       return $this->resources_dir;
     }
 
     if ($driver_name = $this->rc->config->get('calendar_resources_driver')) {
       $driver_class = 'resources_driver_' . $driver_name;
 
       require_once($this->home . '/drivers/resources_driver.php');
       require_once($this->home . '/drivers/' . $driver_name . '/' . $driver_class . '.php');
 
       $this->resources_dir = new $driver_class($this);
     }
 
     return $this->resources_dir;
   }
 
   /**
    * Handler for resoruce autocompletion requests
    */
   public function resources_autocomplete()
   {
     $search = rcube_utils::get_input_value('_search', rcube_utils::INPUT_GPC, true);
     $sid    = rcube_utils::get_input_value('_reqid', rcube_utils::INPUT_GPC);
     $maxnum = (int)$this->rc->config->get('autocomplete_max', 15);
     $results = array();
 
     if ($directory = $this->resources_directory()) {
       foreach ($directory->load_resources($search, $maxnum) as $rec) {
         $results[]  = array(
             'name'  => $rec['name'],
             'email' => $rec['email'],
             'type'  => $rec['_type'],
         );
       }
     }
 
     $this->rc->output->command('ksearch_query_results', $results, $search, $sid);
     $this->rc->output->send();
   }
 
   /**
    * Handler for load-requests for resource data
    */
   function resources_list()
   {
     $data = array();
 
     if ($directory = $this->resources_directory()) {
       foreach ($directory->load_resources() as $rec) {
         $data[] = $rec;
       }
     }
 
     $this->rc->output->command('plugin.resource_data', $data);
     $this->rc->output->send();
   }
 
   /**
    * Handler for requests loading resource owner information
    */
   function resources_owner()
   {
     if ($directory = $this->resources_directory()) {
       $id = rcube_utils::get_input_value('_id', rcube_utils::INPUT_GPC);
       $data = $directory->get_resource_owner($id);
     }
 
     $this->rc->output->command('plugin.resource_owner', $data);
     $this->rc->output->send();
   }
 
   /**
    * Deliver event data for a resource's calendar
    */
   function resources_calendar()
   {
     $events = array();
 
     if ($directory = $this->resources_directory()) {
       $events = $directory->get_resource_calendar(
         rcube_utils::get_input_value('_id', rcube_utils::INPUT_GPC),
         rcube_utils::get_input_value('start', rcube_utils::INPUT_GET),
         rcube_utils::get_input_value('end', rcube_utils::INPUT_GET));
     }
 
     echo $this->encode($events);
     exit;
   }
 
 
   /****  Event invitation plugin hooks ****/
 
   /**
    * Find an event in user calendars
    */
   protected function find_event($event, &$mode)
   {
     $this->load_driver();
 
     // We search for writeable calendars in personal namespace by default
     $mode   = calendar_driver::FILTER_WRITEABLE | calendar_driver::FILTER_PERSONAL;
     $result = $this->driver->get_event($event, $mode);
     // ... now check shared folders if not found
     if (!$result) {
       $result = $this->driver->get_event($event, calendar_driver::FILTER_WRITEABLE | calendar_driver::FILTER_SHARED);
       if ($result) {
         $mode |= calendar_driver::FILTER_SHARED;
       }
     }
 
     return $result;
   }
 
   /**
    * Handler for calendar/itip-status requests
    */
   function event_itip_status()
   {
     $data = rcube_utils::get_input_value('data', rcube_utils::INPUT_POST, true);
 
     $this->load_driver();
 
     // find local copy of the referenced event (in personal namespace)
     $existing  = $this->find_event($data, $mode);
     $is_shared = $mode & calendar_driver::FILTER_SHARED;
     $itip      = $this->load_itip();
     $response  = $itip->get_itip_status($data, $existing);
 
     // get a list of writeable calendars to save new events to
     if ((!$existing || $is_shared)
       && !$data['nosave']
       && ($response['action'] == 'rsvp' || $response['action'] == 'import')
     ) {
       $calendars       = $this->driver->list_calendars($mode);
       $calendar_select = new html_select(array(
           'name'       => 'calendar',
           'id'         => 'itip-saveto',
           'is_escaped' => true,
           'class'      => 'form-control custom-select'
       ));
       $calendar_select->add('--', '');
       $numcals = 0;
       foreach ($calendars as $calendar) {
         if ($calendar['editable']) {
           $calendar_select->add($calendar['name'], $calendar['id']);
           $numcals++;
         }
       }
       if ($numcals < 1)
         $calendar_select = null;
     }
 
     if ($calendar_select) {
       $default_calendar = $this->get_default_calendar($data['sensitivity'], $calendars);
       $response['select'] = html::span('folder-select', $this->gettext('saveincalendar') . '&nbsp;' .
         $calendar_select->show($is_shared ? $existing['calendar'] : $default_calendar['id']));
     }
     else if ($data['nosave']) {
       $response['select'] = html::tag('input', array('type' => 'hidden', 'name' => 'calendar', 'id' => 'itip-saveto', 'value' => ''));
     }
 
     // render small agenda view for the respective day
     if ($data['method'] == 'REQUEST' && !empty($data['date']) && $response['action'] == 'rsvp') {
       $event_start = rcube_utils::anytodatetime($data['date']);
       $day_start   = new Datetime(gmdate('Y-m-d 00:00', $data['date']), $this->lib->timezone);
       $day_end     = new Datetime(gmdate('Y-m-d 23:59', $data['date']), $this->lib->timezone);
 
       // get events on that day from the user's personal calendars
       $calendars = $this->driver->list_calendars(calendar_driver::FILTER_PERSONAL);
       $events = $this->driver->load_events($day_start->format('U'), $day_end->format('U'), null, array_keys($calendars));
       usort($events, function($a, $b) { return $a['start'] > $b['start'] ? 1 : -1; });
 
       $before = $after = array();
       foreach ($events as $event) {
         // TODO: skip events with free_busy == 'free' ?
         if ($event['uid'] == $data['uid']
             || $event['end'] < $day_start || $event['start'] > $day_end
             || $event['status'] == 'CANCELLED'
             || (!empty($event['className']) && strpos($event['className'], 'declined') !== false)
         ) {
           continue;
         }
 
         if ($event['start'] < $event_start)
           $before[] = $this->mail_agenda_event_row($event);
         else
           $after[] = $this->mail_agenda_event_row($event);
       }
 
       $response['append'] = array(
         'selector' => '.calendar-agenda-preview',
         'replacements' => array(
           '%before%' => !empty($before) ? join("\n", array_slice($before,  -3)) : html::div('event-row no-event', $this->gettext('noearlierevents')),
           '%after%'  => !empty($after)  ? join("\n", array_slice($after, 0, 3)) : html::div('event-row no-event', $this->gettext('nolaterevents')),
         ),
       );
     }
 
     $this->rc->output->command('plugin.update_itip_object_status', $response);
   }
 
   /**
    * Handler for calendar/itip-remove requests
    */
   function event_itip_remove()
   {
     $success  = false;
     $uid      = rcube_utils::get_input_value('uid', rcube_utils::INPUT_POST);
     $instance = rcube_utils::get_input_value('_instance', rcube_utils::INPUT_POST);
     $savemode = rcube_utils::get_input_value('_savemode', rcube_utils::INPUT_POST);
     $listmode = calendar_driver::FILTER_WRITEABLE | calendar_driver::FILTER_PERSONAL;
 
     // search for event if only UID is given
     if ($event = $this->driver->get_event(array('uid' => $uid, '_instance' => $instance), $listmode)) {
       $event['_savemode'] = $savemode;
       $success = $this->driver->remove_event($event, true);
     }
 
     if ($success) {
       $this->rc->output->show_message('calendar.successremoval', 'confirmation');
     }
     else {
       $this->rc->output->show_message('calendar.errorsaving', 'error');
     }
   }
 
   /**
    * Handler for URLs that allow an invitee to respond on his invitation mail
    */
   public function itip_attend_response($p)
   {
     $this->setup();
 
     if ($p['action'] == 'attend') {
       $this->ui->init();
 
       $this->rc->output->set_env('task', 'calendar');  // override some env vars
       $this->rc->output->set_env('refresh_interval', 0);
       $this->rc->output->set_pagetitle($this->gettext('calendar'));
 
       $itip  = $this->load_itip();
       $token = rcube_utils::get_input_value('_t', rcube_utils::INPUT_GPC);
 
       // read event info stored under the given token
       if ($invitation = $itip->get_invitation($token)) {
         $this->token = $token;
         $this->event = $invitation['event'];
 
         // show message about cancellation
         if ($invitation['cancelled']) {
           $this->invitestatus = html::div('rsvp-status declined', $itip->gettext('eventcancelled'));
         }
         // save submitted RSVP status
         else if (!empty($_POST['rsvp'])) {
           $status = null;
           foreach (array('accepted','tentative','declined') as $method) {
             if ($_POST['rsvp'] == $itip->gettext('itip' . $method)) {
               $status = $method;
               break;
             }
           }
 
           // send itip reply to organizer
           $invitation['event']['comment'] = rcube_utils::get_input_value('_comment', rcube_utils::INPUT_POST);
           if ($status && $itip->update_invitation($invitation, $invitation['attendee'], strtoupper($status))) {
             $this->invitestatus = html::div('rsvp-status ' . strtolower($status), $itip->gettext('youhave'.strtolower($status)));
           }
           else
             $this->rc->output->command('display_message', $this->gettext('errorsaving'), 'error', -1);
 
           // if user is logged in...
           // FIXME: we should really consider removing this functionality
           //        it's confusing that it creates/updates an event only for logged-in user
           //        what if the logged-in user is not the same as the attendee?
           if ($this->rc->user->ID) {
             $this->load_driver();
 
             $invitation = $itip->get_invitation($token);
             $existing   = $this->driver->get_event($this->event);
 
             // save the event to his/her default calendar if not yet present
             if (!$existing && ($calendar = $this->get_default_calendar($invitation['event']['sensitivity']))) {
               $invitation['event']['calendar'] = $calendar['id'];
               if ($this->driver->new_event($invitation['event']))
                 $this->rc->output->command('display_message', $this->gettext(array('name' => 'importedsuccessfully', 'vars' => array('calendar' => $calendar['name']))), 'confirmation');
               else
                 $this->rc->output->command('display_message', $this->gettext('errorimportingevent'), 'error');
             }
             else if ($existing
               && ($this->event['sequence'] >= $existing['sequence'] || $this->event['changed'] >= $existing['changed'])
               && ($calendar = $this->driver->get_calendar($existing['calendar']))
             ) {
               $this->event       = $invitation['event'];
               $this->event['id'] = $existing['id'];
 
               unset($this->event['comment']);
 
               // merge attendees status
               // e.g. preserve my participant status for regular updates
               $this->lib->merge_attendees($this->event, $existing, $status);
 
               // update attachments list
               $event['deleted_attachments'] = true;
 
               // show me as free when declined (#1670)
               if ($status == 'declined')
                 $this->event['free_busy'] = 'free';
 
               if ($this->driver->edit_event($this->event))
                 $this->rc->output->command('display_message', $this->gettext(array('name' => 'updatedsuccessfully', 'vars' => array('calendar' => $calendar->get_name()))), 'confirmation');
               else
                 $this->rc->output->command('display_message', $this->gettext('errorimportingevent'), 'error');
             }
           }
         }
         
         $this->register_handler('plugin.event_inviteform', array($this, 'itip_event_inviteform'));
         $this->register_handler('plugin.event_invitebox', array($this->ui, 'event_invitebox'));
         
         if (!$this->invitestatus) {
           $this->itip->set_rsvp_actions(array('accepted','tentative','declined'));
           $this->register_handler('plugin.event_rsvp_buttons', array($this->ui, 'event_rsvp_buttons'));
         }
         
         $this->rc->output->set_pagetitle($itip->gettext('itipinvitation') . ' ' . $this->event['title']);
       }
       else
         $this->rc->output->command('display_message', $this->gettext('itipinvalidrequest'), 'error', -1);
       
       $this->rc->output->send('calendar.itipattend');
     }
   }
   
   /**
    *
    */
   public function itip_event_inviteform($attrib)
   {
     $hidden = new html_hiddenfield(array('name' => "_t", 'value' => $this->token));
     return html::tag('form', array('action' => $this->rc->url(array('task' => 'calendar', 'action' => 'attend')), 'method' => 'post', 'noclose' => true) + $attrib) . $hidden->show();
   }
 
   /**
    * 
    */
   private function mail_agenda_event_row($event, $class = '')
   {
     $time = $event['allday'] ? $this->gettext('all-day') :
       $this->rc->format_date($event['start'], $this->rc->config->get('time_format')) . ' - ' .
         $this->rc->format_date($event['end'], $this->rc->config->get('time_format'));
 
     return html::div(rtrim('event-row ' . ($class ?: $event['className'])),
       html::span('event-date', $time) .
       html::span('event-title', rcube::Q($event['title']))
     );
   }
   
   /**
    * 
    */
   public function mail_messages_list($p)
   {
     if (in_array('attachment', (array)$p['cols']) && !empty($p['messages'])) {
       foreach ($p['messages'] as $header) {
         $part = new StdClass;
         $part->mimetype = $header->ctype;
         if (libcalendaring::part_is_vcalendar($part)) {
           $header->list_flags['attachmentClass'] = 'ical';
         }
         else if (in_array($header->ctype, array('multipart/alternative', 'multipart/mixed'))) {
           // TODO: fetch bodystructure and search for ical parts. Maybe too expensive?
           if (!empty($header->structure) && is_array($header->structure->parts)) {
             foreach ($header->structure->parts as $part) {
               if (libcalendaring::part_is_vcalendar($part) && !empty($part->ctype_parameters['method'])) {
                 $header->list_flags['attachmentClass'] = 'ical';
                 break;
               }
             }
           }
         }
       }
     }
   }
 
   /**
    * Add UI element to copy event invitations or updates to the calendar
    */
   public function mail_messagebody_html($p)
   {
     // load iCalendar functions (if necessary)
     if (!empty($this->lib->ical_parts)) {
       $this->get_ical();
       $this->load_itip();
     }
 
     $html = '';
     $has_events = false;
     $ical_objects = $this->lib->get_mail_ical_objects();
 
     // show a box for every event in the file
     foreach ($ical_objects as $idx => $event) {
       if ($event['_type'] != 'event')  // skip non-event objects (#2928)
         continue;
 
       $has_events = true;
 
       // get prepared inline UI for this event object
       if ($ical_objects->method) {
         $append = '';
 
         // prepare a small agenda preview to be filled with actual event data on async request
         if ($ical_objects->method == 'REQUEST') {
           $append = html::div('calendar-agenda-preview',
             html::tag('h3', 'preview-title', $this->gettext('agenda') . ' ' .
               html::span('date', $this->rc->format_date($event['start'], $this->rc->config->get('date_format')))
             ) . '%before%' . $this->mail_agenda_event_row($event, 'current') . '%after%');
         }
 
         $html .= html::div('calendar-invitebox invitebox boxinformation',
           $this->itip->mail_itip_inline_ui(
             $event,
             $ical_objects->method,
             $ical_objects->mime_id . ':' . $idx,
             'calendar',
             rcube_utils::anytodatetime($ical_objects->message_date),
             $this->rc->url(array('task' => 'calendar')) . '&view=agendaDay&date=' . $event['start']->format('U')
           ) . $append
         );
       }
 
       // limit listing
       if ($idx >= 3)
         break;
     }
 
     // prepend event boxes to message body
     if ($html) {
       $this->ui->init();
       $p['content'] = $html . $p['content'];
       $this->rc->output->add_label('calendar.savingdata','calendar.deleteventconfirm','calendar.declinedeleteconfirm');
     }
 
     // add "Save to calendar" button into attachment menu
     if ($has_events) {
       $this->add_button(array(
         'id'         => 'attachmentsavecal',
         'name'       => 'attachmentsavecal',
         'type'       => 'link',
         'wrapper'    => 'li',
         'command'    => 'attachment-save-calendar',
         'class'      => 'icon calendarlink',
         'classact'   => 'icon calendarlink active',
         'innerclass' => 'icon calendar',
         'label'      => 'calendar.savetocalendar',
         ), 'attachmentmenu');
     }
 
     return $p;
   }
 
 
   /**
    * Handler for POST request to import an event attached to a mail message
    */
   public function mail_import_itip()
   {
     $itip_sending = $this->rc->config->get('calendar_itip_send_option', $this->defaults['calendar_itip_send_option']);
 
     $uid     = rcube_utils::get_input_value('_uid', rcube_utils::INPUT_POST);
     $mbox    = rcube_utils::get_input_value('_mbox', rcube_utils::INPUT_POST);
     $mime_id = rcube_utils::get_input_value('_part', rcube_utils::INPUT_POST);
     $status  = rcube_utils::get_input_value('_status', rcube_utils::INPUT_POST);
     $delete  = intval(rcube_utils::get_input_value('_del', rcube_utils::INPUT_POST));
     $noreply = intval(rcube_utils::get_input_value('_noreply', rcube_utils::INPUT_POST));
     $noreply = $noreply || $status == 'needs-action' || $itip_sending === 0;
     $instance = rcube_utils::get_input_value('_instance', rcube_utils::INPUT_POST);
     $savemode = rcube_utils::get_input_value('_savemode', rcube_utils::INPUT_POST);
     $comment  = rcube_utils::get_input_value('_comment', rcube_utils::INPUT_POST);
 
     $error_msg = $this->gettext('errorimportingevent');
     $success   = false;
 
     if ($status == 'delegated') {
       $delegates = rcube_mime::decode_address_list(rcube_utils::get_input_value('_to', rcube_utils::INPUT_POST, true), 1, false);
       $delegate  = reset($delegates);
 
       if (empty($delegate) || empty($delegate['mailto'])) {
         $this->rc->output->command('display_message', $this->rc->gettext('libcalendaring.delegateinvalidaddress'), 'error');
         return;
       }
     }
 
     // successfully parsed events?
     if ($event = $this->lib->mail_get_itip_object($mbox, $uid, $mime_id, 'event')) {
       // forward iTip request to delegatee
       if ($delegate) {
         $rsvpme = rcube_utils::get_input_value('_rsvp', rcube_utils::INPUT_POST);
         $itip   = $this->load_itip();
 
         $event['comment'] = $comment;
 
         if ($itip->delegate_to($event, $delegate, !empty($rsvpme))) {
           $this->rc->output->show_message('calendar.itipsendsuccess', 'confirmation');
         }
         else {
           $this->rc->output->command('display_message', $this->gettext('itipresponseerror'), 'error');
         }
 
         unset($event['comment']);
 
         // the delegator is set to non-participant, thus save as non-blocking
         $event['free_busy'] = 'free';
       }
 
       $mode = calendar_driver::FILTER_PERSONAL
         | calendar_driver::FILTER_SHARED
         | calendar_driver::FILTER_WRITEABLE;
 
       // find writeable calendar to store event
       $cal_id    = rcube_utils::get_input_value('_folder', rcube_utils::INPUT_POST);
       $dontsave  = $cal_id === '' && $event['_method'] == 'REQUEST';
       $calendars = $this->driver->list_calendars($mode);
       $calendar  = $calendars[$cal_id];
 
       // select default calendar except user explicitly selected 'none'
       if (!$calendar && !$dontsave)
          $calendar = $this->get_default_calendar($event['sensitivity'], $calendars);
 
       $metadata = array(
         'uid'       => $event['uid'],
         '_instance' => $event['_instance'],
         'changed'   => is_object($event['changed']) ? $event['changed']->format('U') : 0,
         'sequence'  => intval($event['sequence']),
         'fallback'  => strtoupper($status),
         'method'    => $event['_method'],
         'task'      => 'calendar',
       );
 
       // update my attendee status according to submitted method
       if (!empty($status)) {
         $organizer = null;
         $emails = $this->get_user_emails();
         foreach ($event['attendees'] as $i => $attendee) {
           if ($attendee['role'] == 'ORGANIZER') {
             $organizer = $attendee;
           }
           else if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
             $event['attendees'][$i]['status'] = strtoupper($status);
             if (!in_array($event['attendees'][$i]['status'], array('NEEDS-ACTION','DELEGATED')))
               $event['attendees'][$i]['rsvp'] = false;  // unset RSVP attribute
 
             $metadata['attendee'] = $attendee['email'];
             $metadata['rsvp'] = $attendee['role'] != 'NON-PARTICIPANT';
             $reply_sender = $attendee['email'];
             $event_attendee = $attendee;
           }
         }
 
         // add attendee with this user's default identity if not listed
         if (!$reply_sender) {
           $sender_identity = $this->rc->user->list_emails(true);
           $event['attendees'][] = array(
             'name'   => $sender_identity['name'],
             'email'  => $sender_identity['email'],
             'role'   => 'OPT-PARTICIPANT',
             'status' => strtoupper($status),
           );
           $metadata['attendee'] = $sender_identity['email'];
         }
       }
       
       // save to calendar
       if ($calendar && $calendar['editable']) {
         // check for existing event with the same UID
         $existing = $this->find_event($event, $mode);
 
         // we'll create a new copy if user decided to change the calendar
         if ($existing && $cal_id && $calendar && $calendar['id'] != $existing['calendar']) {
           $existing = null;
         }
 
         if ($existing) {
           $calendar = $calendars[$existing['calendar']];
 
           // forward savemode for correct updates of recurring events
           $existing['_savemode'] = $savemode ?: $event['_savemode'];
 
           // only update attendee status
           if ($event['_method'] == 'REPLY') {
             // try to identify the attendee using the email sender address
             $existing_attendee        = -1;
             $existing_attendee_emails = array();
 
             foreach ($existing['attendees'] as $i => $attendee) {
               $existing_attendee_emails[] = $attendee['email'];
               if ($this->itip->compare_email($attendee['email'], $event['_sender'], $event['_sender_utf'])) {
                 $existing_attendee = $i;
               }
             }
 
             $event_attendee   = null;
             $update_attendees = array();
 
             foreach ($event['attendees'] as $attendee) {
               if ($this->itip->compare_email($attendee['email'], $event['_sender'], $event['_sender_utf'])) {
                 $event_attendee       = $attendee;
                 $update_attendees[]   = $attendee;
                 $metadata['fallback'] = $attendee['status'];
                 $metadata['attendee'] = $attendee['email'];
                 $metadata['rsvp']     = $attendee['rsvp'] || $attendee['role'] != 'NON-PARTICIPANT';
 
                 if ($attendee['status'] != 'DELEGATED') {
                   break;
                 }
               }
               // also copy delegate attendee
               else if (!empty($attendee['delegated-from'])
                 && $this->itip->compare_email($attendee['delegated-from'], $event['_sender'], $event['_sender_utf'])
               ) {
                 $update_attendees[] = $attendee;
                 if (!in_array_nocase($attendee['email'], $existing_attendee_emails)) {
                   $existing['attendees'][] = $attendee;
                 }
               }
             }
 
             // if delegatee has declined, set delegator's RSVP=True
             if ($event_attendee && $event_attendee['status'] == 'DECLINED' && $event_attendee['delegated-from']) {
               foreach ($existing['attendees'] as $i => $attendee) {
                 if ($attendee['email'] == $event_attendee['delegated-from']) {
                   $existing['attendees'][$i]['rsvp'] = true;
                   break;
                 }
               }
             }
 
             // Accept sender as a new participant (different email in From: and the iTip)
             // Use ATTENDEE entry from the iTip with replaced email address
             if (!$event_attendee) {
               // remove the organizer
               $itip_attendees = array_filter($event['attendees'], function($item) { return $item['role'] != 'ORGANIZER'; });
 
               // there must be only one attendee
               if (is_array($itip_attendees) && count($itip_attendees) == 1) {
                 $event_attendee          = $itip_attendees[key($itip_attendees)];
                 $event_attendee['email'] = $event['_sender'];
                 $update_attendees[]      = $event_attendee;
                 $metadata['fallback']    = $event_attendee['status'];
                 $metadata['attendee']    = $event_attendee['email'];
                 $metadata['rsvp']        = $event_attendee['rsvp'] || $event_attendee['role'] != 'NON-PARTICIPANT';
               }
             }
 
             // found matching attendee entry in both existing and new events
             if ($existing_attendee >= 0 && $event_attendee) {
               $existing['attendees'][$existing_attendee] = $event_attendee;
               $success = $this->driver->update_attendees($existing, $update_attendees);
             }
             // update the entire attendees block
             else if (($event['sequence'] >= $existing['sequence'] || $event['changed'] >= $existing['changed']) && $event_attendee) {
               $existing['attendees'][] = $event_attendee;
               $success = $this->driver->update_attendees($existing, $update_attendees);
             }
             else if (!$event_attendee) {
               $error_msg = $this->gettext('errorunknownattendee');
             }
             else {
               $error_msg = $this->gettext('newerversionexists');
             }
           }
           // delete the event when declined (#1670)
           else if ($status == 'declined' && $delete) {
              $deleted = $this->driver->remove_event($existing, true);
              $success = true;
           }
           // import the (newer) event
           else if ($event['sequence'] >= $existing['sequence'] || $event['changed'] >= $existing['changed']) {
             $event['id'] = $existing['id'];
             $event['calendar'] = $existing['calendar'];
 
             // merge attendees status
             // e.g. preserve my participant status for regular updates
             $this->lib->merge_attendees($event, $existing, $status);
 
             // set status=CANCELLED on CANCEL messages
             if ($event['_method'] == 'CANCEL')
               $event['status'] = 'CANCELLED';
 
             // update attachments list, allow attachments update only on REQUEST (#5342)
             if ($event['_method'] == 'REQUEST')
               $event['deleted_attachments'] = true;
             else
               unset($event['attachments']);
 
             // show me as free when declined (#1670)
             if ($status == 'declined' || $event['status'] == 'CANCELLED' || $event_attendee['role'] == 'NON-PARTICIPANT')
               $event['free_busy'] = 'free';
 
             $success = $this->driver->edit_event($event);
           }
           else if (!empty($status)) {
             $existing['attendees'] = $event['attendees'];
             if ($status == 'declined' || $event_attendee['role'] == 'NON-PARTICIPANT')  // show me as free when declined (#1670)
               $existing['free_busy'] = 'free';
             $success = $this->driver->edit_event($existing);
           }
           else
             $error_msg = $this->gettext('newerversionexists');
         }
         else if (!$existing && ($status != 'declined' || $this->rc->config->get('kolab_invitation_calendars'))) {
           if ($status == 'declined' || $event['status'] == 'CANCELLED' || $event_attendee['role'] == 'NON-PARTICIPANT') {
             $event['free_busy'] = 'free';
           }
 
           // if the RSVP reply only refers to a single instance:
           // store unmodified master event with current instance as exception
           if (!empty($instance) && !empty($savemode) && $savemode != 'all') {
             $master = $this->lib->mail_get_itip_object($mbox, $uid, $mime_id, 'event');
             if ($master['recurrence'] && !$master['_instance']) {
               // compute recurring events until this instance's date
               if ($recurrence_date = rcube_utils::anytodatetime($instance, $master['start']->getTimezone())) {
                 $recurrence_date->setTime(23,59,59);
 
                 foreach ($this->driver->get_recurring_events($master, $master['start'], $recurrence_date) as $recurring) {
                   if ($recurring['_instance'] == $instance) {
                     // copy attendees block with my partstat to exception
                     $recurring['attendees'] = $event['attendees'];
                     $master['recurrence']['EXCEPTIONS'][] = $recurring;
                     $event = $recurring;  // set reference for iTip reply
                     break;
                   }
                 }
 
                 $master['calendar'] = $event['calendar'] = $calendar['id'];
                 $success = $this->driver->new_event($master);
               }
               else {
                 $master = null;
               }
             }
             else {
               $master = null;
             }
           }
 
           // save to the selected/default calendar
           if (!$master) {
             $event['calendar'] = $calendar['id'];
             $success = $this->driver->new_event($event);
           }
         }
         else if ($status == 'declined')
           $error_msg = null;
       }
       else if ($status == 'declined' || $dontsave)
         $error_msg = null;
       else
         $error_msg = $this->gettext('nowritecalendarfound');
     }
 
     if ($success) {
       $message = $event['_method'] == 'REPLY' ? 'attendeupdateesuccess' : ($deleted ? 'successremoval' : ($existing ? 'updatedsuccessfully' : 'importedsuccessfully'));
       $this->rc->output->command('display_message', $this->gettext(array('name' => $message, 'vars' => array('calendar' => $calendar['name']))), 'confirmation');
     }
 
     if ($success || $dontsave) {
       $metadata['calendar'] = $event['calendar'];
       $metadata['nosave'] = $dontsave;
       $metadata['rsvp'] = intval($metadata['rsvp']);
       $metadata['after_action'] = $this->rc->config->get('calendar_itip_after_action', $this->defaults['calendar_itip_after_action']);
       $this->rc->output->command('plugin.itip_message_processed', $metadata);
       $error_msg = null;
     }
     else if ($error_msg) {
       $this->rc->output->command('display_message', $error_msg, 'error');
     }
 
     // send iTip reply
     if ($event['_method'] == 'REQUEST' && $organizer && !$noreply && !in_array(strtolower($organizer['email']), $emails) && !$error_msg) {
       $event['comment'] = $comment;
       $itip = $this->load_itip();
       $itip->set_sender_email($reply_sender);
       if ($itip->send_itip_message($event, 'REPLY', $organizer, 'itipsubject' . $status, 'itipmailbody' . $status))
         $this->rc->output->command('display_message', $this->gettext(array('name' => 'sentresponseto', 'vars' => array('mailto' => $organizer['name'] ? $organizer['name'] : $organizer['email']))), 'confirmation');
       else
         $this->rc->output->command('display_message', $this->gettext('itipresponseerror'), 'error');
     }
 
     $this->rc->output->send();
   }
 
   /**
    * Handler for calendar/itip-remove requests
    */
   function mail_itip_decline_reply()
   {
     $uid     = rcube_utils::get_input_value('_uid', rcube_utils::INPUT_POST);
     $mbox    = rcube_utils::get_input_value('_mbox', rcube_utils::INPUT_POST);
     $mime_id = rcube_utils::get_input_value('_part', rcube_utils::INPUT_POST);
 
     if (($event = $this->lib->mail_get_itip_object($mbox, $uid, $mime_id, 'event')) && $event['_method'] == 'REPLY') {
       $event['comment'] = rcube_utils::get_input_value('_comment', rcube_utils::INPUT_POST);
 
       foreach ($event['attendees'] as $_attendee) {
         if ($_attendee['role'] != 'ORGANIZER') {
           $attendee = $_attendee;
           break;
         }
       }
 
       $itip = $this->load_itip();
       if ($itip->send_itip_message($event, 'CANCEL', $attendee, 'itipsubjectcancel', 'itipmailbodycancel'))
         $this->rc->output->command('display_message', $this->gettext(array('name' => 'sentresponseto', 'vars' => array('mailto' => $attendee['name'] ? $attendee['name'] : $attendee['email']))), 'confirmation');
       else
         $this->rc->output->command('display_message', $this->gettext('itipresponseerror'), 'error');
     }
     else {
       $this->rc->output->command('display_message', $this->gettext('itipresponseerror'), 'error');
     }
   }
 
   /**
    * Handler for calendar/itip-delegate requests
    */
   function mail_itip_delegate()
   {
     // forward request to mail_import_itip() with the right status
     $_POST['_status'] = $_REQUEST['_status'] = 'delegated';
     $this->mail_import_itip();
   }
 
   /**
    * Import the full payload from a mail message attachment
    */
   public function mail_import_attachment()
   {
     $uid     = rcube_utils::get_input_value('_uid', rcube_utils::INPUT_POST);
     $mbox    = rcube_utils::get_input_value('_mbox', rcube_utils::INPUT_POST);
     $mime_id = rcube_utils::get_input_value('_part', rcube_utils::INPUT_POST);
     $charset = RCUBE_CHARSET;
 
     // establish imap connection
     $imap = $this->rc->get_storage();
     $imap->set_folder($mbox);
 
     if ($uid && $mime_id) {
       $part = $imap->get_message_part($uid, $mime_id);
       if ($part->ctype_parameters['charset'])
         $charset = $part->ctype_parameters['charset'];
 //      $headers = $imap->get_message_headers($uid);
 
       if ($part) {
         $events = $this->get_ical()->import($part, $charset);
       }
     }
 
     $success = $existing = 0;
     if (!empty($events)) {
       // find writeable calendar to store event
       $cal_id = !empty($_REQUEST['_calendar']) ? rcube_utils::get_input_value('_calendar', rcube_utils::INPUT_POST) : null;
       $calendars = $this->driver->list_calendars(calendar_driver::FILTER_PERSONAL);
 
       foreach ($events as $event) {
         // save to calendar
         $calendar = $calendars[$cal_id] ?: $this->get_default_calendar($event['sensitivity']);
         if ($calendar && $calendar['editable'] && $event['_type'] == 'event') {
           $event['calendar'] = $calendar['id'];
 
           if (!$this->driver->get_event($event['uid'], calendar_driver::FILTER_WRITEABLE)) {
             $success += (bool)$this->driver->new_event($event);
           }
           else {
             $existing++;
           }
         }
       }
     }
 
     if ($success) {
       $this->rc->output->command('display_message', $this->gettext(array(
         'name' => 'importsuccess',
         'vars' => array('nr' => $success),
       )), 'confirmation');
     }
     else if ($existing) {
       $this->rc->output->command('display_message', $this->gettext('importwarningexists'), 'warning');
     }
     else {
       $this->rc->output->command('display_message', $this->gettext('errorimportingevent'), 'error');
     }
   }
 
   /**
    * Read email message and return contents for a new event based on that message
    */
   public function mail_message2event()
   {
     $this->ui->init();
     $this->ui->addJS();
     $this->ui->init_templates();
     $this->ui->calendar_list(array(), true); // set env['calendars']
 
     $uid   = rcube_utils::get_input_value('_uid', rcube_utils::INPUT_GET);
     $mbox  = rcube_utils::get_input_value('_mbox', rcube_utils::INPUT_GET);
     $event = array();
 
     // establish imap connection
     $imap    = $this->rc->get_storage();
     $message = new rcube_message($uid, $mbox);
 
     if ($message->headers) {
       $event['title']       = trim($message->subject);
       $event['description'] = trim($message->first_text_part());
 
       $this->load_driver();
 
       // add a reference to the email message
       if ($msgref = $this->driver->get_message_reference($message->headers, $mbox)) {
         $event['links'] = array($msgref);
       }
       // copy mail attachments to event
       else if ($message->attachments) {
         $eventid = 'cal-';
         if (!is_array($_SESSION[self::SESSION_KEY]) || $_SESSION[self::SESSION_KEY]['id'] != $eventid) {
           $_SESSION[self::SESSION_KEY] = array();
           $_SESSION[self::SESSION_KEY]['id'] = $eventid;
           $_SESSION[self::SESSION_KEY]['attachments'] = array();
         }
 
         foreach ((array)$message->attachments as $part) {
           $attachment = array(
             'data' => $imap->get_message_part($uid, $part->mime_id, $part),
             'size' => $part->size,
             'name' => $part->filename,
             'mimetype' => $part->mimetype,
             'group' => $eventid,
           );
 
           $attachment = $this->rc->plugins->exec_hook('attachment_save', $attachment);
 
           if ($attachment['status'] && !$attachment['abort']) {
             $id = $attachment['id'];
             $attachment['classname'] = rcube_utils::file2class($attachment['mimetype'], $attachment['name']);
 
             // store new attachment in session
             unset($attachment['status'], $attachment['abort'], $attachment['data']);
             $_SESSION[self::SESSION_KEY]['attachments'][$id] = $attachment;
 
             $attachment['id'] = 'rcmfile' . $attachment['id'];  // add prefix to consider it 'new'
             $event['attachments'][] = $attachment;
           }
         }
       }
 
       $this->rc->output->set_env('event_prop', $event);
     }
     else {
       $this->rc->output->command('display_message', $this->gettext('messageopenerror'), 'error');
     }
 
     $this->rc->output->send('calendar.dialog');
   }
 
   /**
    * Handler for the 'message_compose' plugin hook. This will check for
    * a compose parameter 'calendar_event' and create an attachment with the
    * referenced event in iCal format
    */
   public function mail_message_compose($args)
   {
     // set the submitted event ID as attachment
     if (!empty($args['param']['calendar_event'])) {
       $this->load_driver();
 
       list($cal, $id) = explode(':', $args['param']['calendar_event'], 2);
       if ($event = $this->driver->get_event(array('id' => $id, 'calendar' => $cal))) {
         $filename = asciiwords($event['title']);
         if (empty($filename))
           $filename = 'event';
 
         // save ics to a temp file and register as attachment
         $tmp_path = tempnam($this->rc->config->get('temp_dir'), 'rcmAttmntCal');
         file_put_contents($tmp_path, $this->get_ical()->export(array($event), '', false, array($this->driver, 'get_attachment_body')));
 
         $args['attachments'][] = array(
           'path'     => $tmp_path,
           'name'     => $filename . '.ics',
           'mimetype' => 'text/calendar',
           'size'     => filesize($tmp_path),
         );
         $args['param']['subject'] = $event['title'];
       }
     }
 
     return $args;
   }
 
 
   /**
    * Get a list of email addresses of the current user (from login and identities)
    */
   public function get_user_emails()
   {
     return $this->lib->get_user_emails();
   }
 
 
   /**
    * Build an absolute URL with the given parameters
    */
   public function get_url($param = array())
   {
     $param += array('task' => 'calendar');
     return $this->rc->url($param, true, true);
   }
 
 
   public function ical_feed_hash($source)
   {
     return base64_encode($this->rc->user->get_username() . ':' . $source);
   }
 
   /**
    * Handler for user_delete plugin hook
    */
   public function user_delete($args)
   {
      // delete itipinvitations entries related to this user
      $db = $this->rc->get_dbh();
      $table_itipinvitations = $db->table_name('itipinvitations', true);
      $db->query("DELETE FROM $table_itipinvitations WHERE `user_id` = ?", $args['user']->ID);
 
      $this->setup();
      $this->load_driver();
      return $this->driver->user_delete($args);
   }
 
   /**
    * Find first occurrence of a recurring event excluding start date
    *
    * @param array $event Event data (with 'start' and 'recurrence')
    *
    * @return DateTime Date of the first occurrence
    */
   public function find_first_occurrence($event)
   {
     // Make sure libkolab plugin is loaded in case of Kolab driver
     $this->load_driver();
 
     // Use libkolab to compute recurring events (and libkolab plugin)
     // Horde-based fallback has many bugs
     if (class_exists('kolabformat') && class_exists('kolabcalendaring') && class_exists('kolab_date_recurrence')) {
       $object = kolab_format::factory('event', 3.0);
       $object->set($event);
 
       $recurrence = new kolab_date_recurrence($object);
     }
     else {
       // fallback to libcalendaring (Horde-based) recurrence implementation
       require_once(__DIR__ . '/lib/calendar_recurrence.php');
       $recurrence = new calendar_recurrence($this, $event);
     }
 
     return $recurrence->first_occurrence();
   }
 
   /**
    * Magic getter for public access to protected members
    */
   public function __get($name)
   {
     switch ($name) {
       case 'ical':
         return $this->get_ical();
 
       case 'itip':
         return $this->load_itip();
 
       case 'driver':
         $this->load_driver();
         return $this->driver;
     }
 
     return null;
   }
 
 }
diff --git a/plugins/calendar/lib/calendar_ui.php b/plugins/calendar/lib/calendar_ui.php
index 3e3d77ad..13c71b52 100644
--- a/plugins/calendar/lib/calendar_ui.php
+++ b/plugins/calendar/lib/calendar_ui.php
@@ -1,866 +1,876 @@
 <?php
 /**
  * User Interface class for the Calendar plugin
  *
  * @author Lazlo Westerhof <hello@lazlo.me>
  * @author Thomas Bruederli <bruederli@kolabsys.com>
  *
  * Copyright (C) 2010, Lazlo Westerhof <hello@lazlo.me>
  * Copyright (C) 2014, Kolab Systems AG <contact@kolabsys.com>
  *
  * 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/>.
  */
 
 
 class calendar_ui
 {
   private $rc;
   private $cal;
   private $ready = false;
   public $screen;
 
   function __construct($cal)
   {
     $this->cal = $cal;
     $this->rc = $cal->rc;
     $this->screen = $this->rc->task == 'calendar' ? ($this->rc->action ? $this->rc->action: 'calendar') : 'other';
   }
 
   /**
    * Calendar UI initialization and requests handlers
    */
   public function init()
   {
     if ($this->ready)  // already done
       return;
 
     // add taskbar button
     $this->cal->add_button(array(
       'command'    => 'calendar',
       'class'      => 'button-calendar',
       'classsel'   => 'button-calendar button-selected',
       'innerclass' => 'button-inner',
       'label'      => 'calendar.calendar',
       'type'       => 'link'
       ), 'taskbar');
     
     // load basic client script
     if ($this->rc->action != 'print') {
       $this->cal->include_script('calendar_base.js');
     }
 
     $skin_path = $this->cal->local_skin_path();
     $this->cal->include_stylesheet($skin_path . '/calendar.css');
     
     $this->ready = true;
   }
 
   /**
    * Register handler methods for the template engine
    */
   public function init_templates()
   {
     $this->cal->register_handler('plugin.calendar_css', array($this, 'calendar_css'));
     $this->cal->register_handler('plugin.calendar_list', array($this, 'calendar_list'));
     $this->cal->register_handler('plugin.calendar_select', array($this, 'calendar_select'));
     $this->cal->register_handler('plugin.identity_select', array($this, 'identity_select'));
     $this->cal->register_handler('plugin.category_select', array($this, 'category_select'));
     $this->cal->register_handler('plugin.status_select', array($this, 'status_select'));
     $this->cal->register_handler('plugin.freebusy_select', array($this, 'freebusy_select'));
     $this->cal->register_handler('plugin.priority_select', array($this, 'priority_select'));
     $this->cal->register_handler('plugin.sensitivity_select', array($this, 'sensitivity_select'));
     $this->cal->register_handler('plugin.alarm_select', array($this, 'alarm_select'));
     $this->cal->register_handler('plugin.recurrence_form', array($this->cal->lib, 'recurrence_form'));
     $this->cal->register_handler('plugin.attendees_list', array($this, 'attendees_list'));
     $this->cal->register_handler('plugin.attendees_form', array($this, 'attendees_form'));
     $this->cal->register_handler('plugin.resources_form', array($this, 'resources_form'));
     $this->cal->register_handler('plugin.resources_list', array($this, 'resources_list'));
     $this->cal->register_handler('plugin.resources_searchform', array($this, 'resources_search_form'));
     $this->cal->register_handler('plugin.resource_info', array($this, 'resource_info'));
     $this->cal->register_handler('plugin.resource_calendar', array($this, 'resource_calendar'));
     $this->cal->register_handler('plugin.attendees_freebusy_table', array($this, 'attendees_freebusy_table'));
     $this->cal->register_handler('plugin.edit_attendees_notify', array($this, 'edit_attendees_notify'));
     $this->cal->register_handler('plugin.edit_recurrence_sync', array($this, 'edit_recurrence_sync'));
     $this->cal->register_handler('plugin.edit_recurring_warning', array($this, 'recurring_event_warning'));
     $this->cal->register_handler('plugin.event_rsvp_buttons', array($this, 'event_rsvp_buttons'));
     $this->cal->register_handler('plugin.agenda_options', array($this, 'agenda_options'));
     $this->cal->register_handler('plugin.events_import_form', array($this, 'events_import_form'));
     $this->cal->register_handler('plugin.events_export_form', array($this, 'events_export_form'));
     $this->cal->register_handler('plugin.object_changelog_table', array('libkolab', 'object_changelog_table'));
     $this->cal->register_handler('plugin.searchform', array($this->rc->output, 'search_form'));  // use generic method from rcube_template
 
     kolab_attachments_handler::ui();
   }
 
   /**
    * Adds CSS stylesheets to the page header
    */
   public function addCSS()
   {
     $skin_path = $this->cal->local_skin_path();
     $this->cal->include_stylesheet($skin_path . '/fullcalendar.css');
+
+    if ($this->rc->task == 'calendar' && $this->rc->action == 'print') {
+      $this->cal->include_stylesheet($skin_path . '/print.css');
+    }
   }
 
   /**
    * Adds JS files to the page header
    */
   public function addJS()
   {
-    $this->cal->include_script('calendar_ui.js');
+    $this->cal->include_script('lib/js/moment.js');
     $this->cal->include_script('lib/js/fullcalendar.js');
-    $this->rc->output->include_script('treelist.js');
-    $this->cal->api->include_script('libkolab/libkolab.js');
 
-    jqueryui::miniColors();
+    if ($this->rc->task == 'calendar' && $this->rc->action == 'print') {
+      $this->cal->include_script('print.js');
+    }
+    else {
+      $this->rc->output->include_script('treelist.js');
+      $this->cal->api->include_script('libkolab/libkolab.js');
+      $this->cal->include_script('calendar_ui.js');
+      jqueryui::miniColors();
+    }
   }
 
   /**
    *
    */
   function calendar_css($attrib = array())
   {
     $mode = $this->rc->config->get('calendar_event_coloring', $this->cal->defaults['calendar_event_coloring']);
     $categories = $this->cal->driver->list_categories();
     $css = "\n";
     
     foreach ((array)$categories as $class => $color) {
       if (empty($color))
         continue;
       
       $class = 'cat-' . asciiwords(strtolower($class), true);
       $css  .= ".$class { color: #$color }\n";
       if ($mode > 0) {
         if ($mode == 2) {
           $css .= ".fc-event-$class .fc-event-bg {";
           $css .= " opacity: 0.9;";
           $css .= " filter: alpha(opacity=90);";
         }
         else {
           $css .= ".fc-event-$class.fc-event-skin, ";
           $css .= ".fc-event-$class .fc-event-skin, ";
           $css .= ".fc-event-$class .fc-event-inner {";
         }
         $css .= " background-color: #" . $color . ";";
         if ($mode % 2)
           $css .= " border-color: #$color;";
         $css .= "}\n";
       }
     }
     
     $calendars = $this->cal->driver->list_calendars();
     foreach ((array)$calendars as $id => $prop) {
       if (!$prop['color'])
         continue;
       $css .= $this->calendar_css_classes($id, $prop, $mode, $attrib);
     }
     
     return html::tag('style', array('type' => 'text/css'), $css);
   }
 
   /**
    *
    */
   public function calendar_css_classes($id, $prop, $mode, $attrib = array())
   {
     $color = $folder_color = $prop['color'];
 
     // replace white with skin-defined color
     if (!empty($attrib['folder-fallback-color']) && preg_match('/^f+$/i', $folder_color)) {
         $folder_color = $attrib['folder-fallback-color'];
     }
 
     $class = 'cal-' . asciiwords($id, true);
     $css   = str_replace('$class', $class, $attrib['folder-class']) ?: "li .$class";
     $css  .= ", #eventshow .$class { color: #$folder_color; }\n";
 
     if ($mode != 1) {
       if ($mode == 3) {
         $css .= ".fc-event-$class .fc-event-bg {";
         $css .= " opacity: 0.9;";
         $css .= " filter: alpha(opacity=90);";
       }
       else {
         $css .= ".fc-event-$class, ";
         $css .= ".fc-event-$class .fc-event-inner {";
       }
       if (!$prop['printmode'])
         $css .= " background-color: #$color;";
       if ($mode % 2 == 0)
       $css .= " border-color: #$color;";
       $css .= "}\n";
     }
 
     return $css . ".$class .handle { background-color: #$color; }\n";
   }
 
   /**
    *
    */
   function calendar_list($attrib = array(), $js_only = false)
   {
     $html      = '';
     $jsenv     = array();
     $tree      = true;
     $calendars = $this->cal->driver->list_calendars(0, $tree);
 
     // walk folder tree
     if (is_object($tree)) {
       $html = $this->list_tree_html($tree, $calendars, $jsenv, $attrib);
 
       // append birthdays calendar which isn't part of $tree
       if ($bdaycal = $calendars[calendar_driver::BIRTHDAY_CALENDAR_ID]) {
         $calendars = array(calendar_driver::BIRTHDAY_CALENDAR_ID => $bdaycal);
       }
       else {
         $calendars = array();  // clear array for flat listing
       }
     }
     else {
       // fall-back to flat folder listing
       $attrib['class'] .= ' flat';
     }
 
     foreach ((array)$calendars as $id => $prop) {
       if ($attrib['activeonly'] && !$prop['active'])
         continue;
 
       $html .= html::tag('li', array('id' => 'rcmlical' . $id, 'class' => $prop['group']),
         $content = $this->calendar_list_item($id, $prop, $jsenv, $attrib['activeonly'])
       );
     }
 
     $this->rc->output->set_env('calendars', $jsenv);
 
     if ($js_only) {
       return;
     }
 
     $this->rc->output->set_env('source', rcube_utils::get_input_value('source', rcube_utils::INPUT_GET));
     $this->rc->output->add_gui_object('calendarslist', $attrib['id'] ?: 'unknown');
 
     return html::tag('ul', $attrib, $html, html::$common_attrib);
   }
 
   /**
    * Return html for a structured list <ul> for the folder tree
    */
   public function list_tree_html($node, $data, &$jsenv, $attrib)
   {
     $out = '';
     foreach ($node->children as $folder) {
       $id = $folder->id;
       $prop = $data[$id];
       $is_collapsed = false; // TODO: determine this somehow?
 
       $content = $this->calendar_list_item($id, $prop, $jsenv, $attrib['activeonly']);
 
       if (!empty($folder->children)) {
         $content .= html::tag('ul', array('style' => ($is_collapsed ? "display:none;" : null)),
           $this->list_tree_html($folder, $data, $jsenv, $attrib));
       }
 
       if (strlen($content)) {
         $out .= html::tag('li', array(
             'id' => 'rcmlical' . rcube_utils::html_identifier($id),
             'class' => $prop['group'] . ($prop['virtual'] ? ' virtual' : ''),
           ),
           $content);
       }
     }
 
     return $out;
   }
 
   /**
    * Helper method to build a calendar list item (HTML content and js data)
    */
   public function calendar_list_item($id, $prop, &$jsenv, $activeonly = false)
   {
     // enrich calendar properties with settings from the driver
     if (!$prop['virtual']) {
       unset($prop['user_id']);
       $prop['alarms']      = $this->cal->driver->alarms;
       $prop['attendees']   = $this->cal->driver->attendees;
       $prop['freebusy']    = $this->cal->driver->freebusy;
       $prop['attachments'] = $this->cal->driver->attachments;
       $prop['undelete']    = $this->cal->driver->undelete;
       $prop['feedurl']     = $this->cal->get_url(array('_cal' => $this->cal->ical_feed_hash($id) . '.ics', 'action' => 'feed'));
 
       $jsenv[$id] = $prop;
     }
 
     $classes = array('calendar', 'cal-'  . asciiwords($id, true));
     $title = $prop['title'] ?: ($prop['name'] != $prop['listname'] || strlen($prop['name']) > 25 ?
       html_entity_decode($prop['name'], ENT_COMPAT, RCUBE_CHARSET) : '');
 
     if ($prop['virtual'])
       $classes[] = 'virtual';
     else if (!$prop['editable'])
       $classes[] = 'readonly';
     if ($prop['subscribed'])
       $classes[] = 'subscribed';
     if ($prop['subscribed'] === 2)
       $classes[] = 'partial';
     if ($prop['class'])
       $classes[] = $prop['class'];
 
     $content = '';
     if (!$activeonly || $prop['active']) {
       $label_id = 'cl:' . $id;
       $content = html::div(join(' ', $classes),
         html::a(array('class' => 'calname', 'id' => $label_id, 'title' => $title, 'href' => '#'), rcube::Q($prop['editname'] ?: $prop['listname']))
         . ($prop['virtual'] ? '' :
           html::tag('input', array('type' => 'checkbox', 'name' => '_cal[]', 'value' => $id, 'checked' => $prop['active'], 'aria-labelledby' => $label_id), '') .
           html::span('actions', 
             ($prop['removable'] ? html::a(array('href' => '#', 'class' => 'remove', 'title' => $this->cal->gettext('removelist')), ' ') : '') .
             html::a(array('href' => '#', 'class' => 'quickview', 'title' => $this->cal->gettext('quickview'), 'role' => 'checkbox', 'aria-checked' => 'false'), '') .
             (isset($prop['subscribed']) ? html::a(array('href' => '#', 'class' => 'subscribed', 'title' => $this->cal->gettext('calendarsubscribe'), 'role' => 'checkbox', 'aria-checked' => $prop['subscribed'] ? 'true' : 'false'), ' ') : '')
           ) .
           html::span(array('class' => 'handle', 'style' => "background-color: #" . ($prop['color'] ?: 'f00')), '&nbsp;')
         )
       );
     }
 
     return $content;
   }
 
   /**
    * Render a HTML for agenda options form
    */
   function agenda_options($attrib = array())
   {
     $attrib += array('id' => 'agendaoptions');
     $attrib['style'] .= 'display:none';
 
     $select_range = new html_select(array('name' => 'listrange', 'id' => 'agenda-listrange', 'class' => 'form-control custom-select'));
     $select_range->add(1 . ' ' . preg_replace('/\(.+\)/', '', $this->cal->lib->gettext('days')), $days);
     foreach (array(2,5,7,14,30,60,90,180,365) as $days)
       $select_range->add($days . ' ' . preg_replace('/\(|\)/', '', $this->cal->lib->gettext('days')), $days);
 
     $html = html::span('input-group',
         html::label(array('for' => 'agenda-listrange', 'class' => 'input-group-prepend'),
             html::span('input-group-text', $this->cal->gettext('listrange')))
         . $select_range->show($this->rc->config->get('calendar_agenda_range', $this->cal->defaults['calendar_agenda_range']))
     );
 
     $select_sections = new html_select(array('name' => 'listsections', 'id' => 'agenda-listsections', 'class' => 'form-control custom-select'));
     $select_sections->add('---', '');
     foreach (array('day' => 'libcalendaring.days', 'week' => 'libcalendaring.weeks', 'month' => 'libcalendaring.months', 'smart' => 'calendar.smartsections') as $val => $label)
       $select_sections->add(preg_replace('/\(|\)/', '', ucfirst($this->rc->gettext($label))), $val);
 
     $html .= html::span('input-group',
         html::label(array('for' => 'agenda-listsections', 'class' => 'input-group-prepend'),
             html::span('input-group-text', $this->cal->gettext('listsections')))
         . $select_sections->show($this->rc->config->get('calendar_agenda_sections', $this->cal->defaults['calendar_agenda_sections']))
     );
 
     return html::div($attrib, $html);
   }
 
   /**
    * Render a HTML select box for calendar selection
    */
   function calendar_select($attrib = array())
   {
     $attrib['name']       = 'calendar';
     $attrib['is_escaped'] = true;
     $select = new html_select($attrib);
 
     foreach ((array)$this->cal->driver->list_calendars() as $id => $prop) {
       if ($prop['editable'] || strpos($prop['rights'], 'i') !== false)
         $select->add($prop['name'], $id);
     }
 
     return $select->show(null);
   }
 
   /**
    * Render a HTML select box for user identity selection
    */
   function identity_select($attrib = array())
   {
     $attrib['name'] = 'identity';
     $select         = new html_select($attrib);
     $identities     = $this->rc->user->list_emails();
 
     foreach ($identities as $ident) {
         $select->add(format_email_recipient($ident['email'], $ident['name']), $ident['identity_id']);
     }
 
     return $select->show(null);
   }
 
   /**
    * Render a HTML select box to select an event category
    */
   function category_select($attrib = array())
   {
     $attrib['name'] = 'categories';
     $select = new html_select($attrib);
     $select->add('---', '');
     foreach (array_keys((array)$this->cal->driver->list_categories()) as $cat) {
       $select->add($cat, $cat);
     }
 
     return $select->show(null);
   }
 
   /**
    * Render a HTML select box for status property
    */
   function status_select($attrib = array())
   {
     $attrib['name'] = 'status';
     $select = new html_select($attrib);
     $select->add('---', '');
     $select->add($this->cal->gettext('status-confirmed'), 'CONFIRMED');
     $select->add($this->cal->gettext('status-cancelled'), 'CANCELLED');
     $select->add($this->cal->gettext('status-tentative'), 'TENTATIVE');
     return $select->show(null);
   }
 
   /**
    * Render a HTML select box for free/busy/out-of-office property
    */
   function freebusy_select($attrib = array())
   {
     $attrib['name'] = 'freebusy';
     $select = new html_select($attrib);
     $select->add($this->cal->gettext('free'), 'free');
     $select->add($this->cal->gettext('busy'), 'busy');
     // out-of-office is not supported by libkolabxml (#3220)
     // $select->add($this->cal->gettext('outofoffice'), 'outofoffice');
     $select->add($this->cal->gettext('tentative'), 'tentative');
     return $select->show(null);
   }
 
   /**
    * Render a HTML select for event priorities
    */
   function priority_select($attrib = array())
   {
     $attrib['name'] = 'priority';
     $select = new html_select($attrib);
     $select->add('---', '0');
     $select->add('1 '.$this->cal->gettext('highest'), '1');
     $select->add('2 '.$this->cal->gettext('high'),    '2');
     $select->add('3 ',                                '3');
     $select->add('4 ',                                '4');
     $select->add('5 '.$this->cal->gettext('normal'),  '5');
     $select->add('6 ',                                '6');
     $select->add('7 ',                                '7');
     $select->add('8 '.$this->cal->gettext('low'),     '8');
     $select->add('9 '.$this->cal->gettext('lowest'),  '9');
     return $select->show(null);
   }
   
   /**
    * Render HTML input for sensitivity selection
    */
   function sensitivity_select($attrib = array())
   {
     $attrib['name'] = 'sensitivity';
     $select = new html_select($attrib);
     $select->add($this->cal->gettext('public'), 'public');
     $select->add($this->cal->gettext('private'), 'private');
     $select->add($this->cal->gettext('confidential'), 'confidential');
     return $select->show(null);
   }
   
   /**
    * Render HTML form for alarm configuration
    */
   function alarm_select($attrib = array())
   {
     return $this->cal->lib->alarm_select($attrib, $this->cal->driver->alarm_types, $this->cal->driver->alarm_absolute);
   }
 
   /**
    * Render HTML for attendee notification warning
    */
   function edit_attendees_notify($attrib = array())
   {
     $checkbox = new html_checkbox(array('name' => '_notify', 'id' => 'edit-attendees-donotify', 'value' => 1, 'class' => 'pretty-checkbox'));
     return html::div($attrib, html::label(null, $checkbox->show(1) . ' ' . $this->cal->gettext('sendnotifications')));
   }
 
   /**
    * Render HTML for recurrence option to align start date with the recurrence rule
    */
   function edit_recurrence_sync($attrib = array())
   {
     $checkbox = new html_checkbox(array('name' => '_start_sync', 'value' => 1, 'class' => 'pretty-checkbox'));
     return html::div($attrib, html::label(null, $checkbox->show(1) . ' ' . $this->cal->gettext('eventstartsync')));
   }
 
   /**
    * Generate the form for recurrence settings
    */
   function recurring_event_warning($attrib = array())
   {
     $attrib['id'] = 'edit-recurring-warning';
 
     $radio = new html_radiobutton(array('name' => '_savemode', 'class' => 'edit-recurring-savemode'));
     $form = html::label(null, $radio->show('', array('value' => 'current')) . $this->cal->gettext('currentevent')) . ' ' .
        html::label(null, $radio->show('', array('value' => 'future')) . $this->cal->gettext('futurevents')) . ' ' .
        html::label(null, $radio->show('all', array('value' => 'all')) . $this->cal->gettext('allevents')) . ' ' .
        html::label(null, $radio->show('', array('value' => 'new')) . $this->cal->gettext('saveasnew'));
 
     return html::div($attrib, html::div('message', $this->cal->gettext('changerecurringeventwarning')) . html::div('savemode', $form));
   }
 
   /**
    * Form for uploading and importing events
    */
   function events_import_form($attrib = array())
   {
     if (!$attrib['id'])
       $attrib['id'] = 'rcmImportForm';
 
     // Get max filesize, enable upload progress bar
     $max_filesize = $this->rc->upload_init();
 
     $accept = '.ics, text/calendar, text/x-vcalendar, application/ics';
     if (class_exists('ZipArchive', false)) {
       $accept .= ', .zip, application/zip';
     }
 
     $input = new html_inputfield(array(
         'type'   => 'file',
         'name'   => '_data',
         'size'   => $attrib['uploadfieldsize'],
         'accept' => $accept
     ));
 
     $select = new html_select(array('name' => '_range', 'id' => 'event-import-range'));
     $select->add(array(
         $this->cal->gettext('onemonthback'),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>2))),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>3))),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>6))),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>12))),
         $this->cal->gettext('all'),
       ),
       array('1','2','3','6','12',0));
 
     $html = html::div('form-section form-group row',
       html::label(array('class' => 'col-sm-4 col-form-label', 'for' => 'importfile'), rcube::Q($this->rc->gettext('importfromfile')))
       . html::div('col-sm-8', $input->show()
         . html::div('hint', $this->rc->gettext(array('id' => 'importfile', 'name' => 'maxuploadsize', 'vars' => array('size' => $max_filesize)))))
     );
 
     $html .= html::div('form-section form-group row',
       html::label(array('for' => 'event-import-calendar', 'class' => 'col-form-label col-sm-4'), $this->cal->gettext('calendar'))
       . html::div('col-sm-8', $this->calendar_select(array('name' => 'calendar', 'id' => 'event-import-calendar')))
     );
 
     $html .= html::div('form-section form-group row',
       html::label(array('for' => 'event-import-range', 'class' => 'col-form-label col-sm-4'), $this->cal->gettext('importrange'))
       . html::div('col-sm-8', $select->show(1))
     );
 
     $this->rc->output->add_gui_object('importform', $attrib['id']);
     $this->rc->output->add_label('import');
 
     return html::tag('p', null, $this->cal->gettext('importtext'))
       . html::tag('form', array(
           'action'  => $this->rc->url(array('task' => 'calendar', 'action' => 'import_events')),
           'method'  => 'post',
           'enctype' => 'multipart/form-data',
           'id'      => $attrib['id']
         ), $html);
   }
 
   /**
    * Form to select options for exporting events
    */
   function events_export_form($attrib = array())
   {
     if (!$attrib['id'])
       $attrib['id'] = 'rcmExportForm';
 
     $html = html::div('form-section form-group row',
       html::label(array('for' => 'event-export-calendar', 'class' => 'col-sm-4 col-form-label'), $this->cal->gettext('calendar'))
         . html::div('col-sm-8', $this->calendar_select(array('name' => 'calendar', 'id' => 'event-export-calendar', 'class' => 'form-control custom-select'))));
 
     $select = new html_select(array('name' => 'range', 'id' => 'event-export-range', 'class' => 'form-control custom-select'));
     $select->add(array(
         $this->cal->gettext('all'),
         $this->cal->gettext('onemonthback'),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>2))),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>3))),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>6))),
         $this->cal->gettext(array('name' => 'nmonthsback', 'vars' => array('nr'=>12))),
         $this->cal->gettext('customdate'),
       ),
       array(0,'1','2','3','6','12','custom'));
 
     $startdate = new html_inputfield(array('name' => 'start', 'size' => 11, 'id' => 'event-export-startdate'));
 
     $html .= html::div('form-section form-group row',
       html::label(array('for' => 'event-export-range', 'class' => 'col-sm-4 col-form-label'), $this->cal->gettext('exportrange'))
         . html::div('col-sm-8', $select->show(0) . html::span(array('style'=>'display:none'), $startdate->show())));
 
     $checkbox = new html_checkbox(array('name' => 'attachments', 'id' => 'event-export-attachments', 'value' => 1, 'class' => 'form-check-input pretty-checkbox'));
     $html .= html::div('form-section form-check row',
       html::label(array('for' => 'event-export-attachments', 'class' => 'col-sm-4 col-form-label'), $this->cal->gettext('exportattachments'))
         . html::div('col-sm-8', $checkbox->show(1)));
 
     $this->rc->output->add_gui_object('exportform', $attrib['id']);
 
     return html::tag('form', $attrib + array(
         'action' => $this->rc->url(array('task' => 'calendar', 'action' => 'export_events')),
         'method' => "post",
         'id' => $attrib['id']
       ),
       $html
     );
   }
 
   /**
    * Handler for calendar form template.
    * The form content could be overriden by the driver
    */
   function calendar_editform($action, $calendar = array())
   {
     $this->action   = $action;
     $this->calendar = $calendar;
 
     // load miniColors js/css files
     jqueryui::miniColors();
 
     $this->rc->output->set_env('pagetitle', $this->cal->gettext('calendarprops'));
     $this->rc->output->add_handler('folderform', array($this, 'calendarform'));
     $this->rc->output->send('libkolab.folderform');
   }
 
   /**
    * Handler for calendar form template.
    * The form content could be overriden by the driver
    */
   function calendarform($attrib)
   {
     // compose default calendar form fields
     $input_name  = new html_inputfield(array('name' => 'name', 'id' => 'calendar-name', 'size' => 20));
     $input_color = new html_inputfield(array('name' => 'color', 'id' => 'calendar-color', 'size' => 7, 'class' => 'colors'));
 
     $formfields = array(
       'name' => array(
         'label' => $this->cal->gettext('name'),
         'value' => $input_name->show($calendar['name']),
         'id'    => 'calendar-name',
       ),
       'color' => array(
         'label' => $this->cal->gettext('color'),
         'value' => $input_color->show($calendar['color']),
         'id'    => 'calendar-color',
       ),
     );
 
     if ($this->cal->driver->alarms) {
       $checkbox = new html_checkbox(array('name' => 'showalarms', 'id' => 'calendar-showalarms', 'value' => 1));
       $formfields['showalarms'] = array(
         'label' => $this->cal->gettext('showalarms'),
         'value' => $checkbox->show($this->calendar['showalarms'] ? 1 :0),
         'id'    => 'calendar-showalarms',
       );
     }
 
     // allow driver to extend or replace the form content
     return html::tag('form', $attrib + array('action' => "#", 'method' => "get", 'id' => 'calendarpropform'),
       $this->cal->driver->calendar_form($this->action, $this->calendar, $formfields)
     );
   }
 
   /**
    *
    */
   function attendees_list($attrib = array())
   {
     // add "noreply" checkbox to attendees table only
     $invitations = strpos($attrib['id'], 'attend') !== false;
 
     $invite = new html_checkbox(array('value' => 1, 'id' => 'edit-attendees-invite'));
     $table  = new html_table(array('cols' => 5 + intval($invitations), 'border' => 0, 'cellpadding' => 0, 'class' => 'rectable'));
 
     $table->add_header('role', $this->cal->gettext('role'));
     $table->add_header('name', $this->cal->gettext($attrib['coltitle'] ?: 'attendee'));
     $table->add_header('availability', $this->cal->gettext('availability'));
     $table->add_header('confirmstate', $this->cal->gettext('confirmstate'));
     if ($invitations) {
       $table->add_header(array('class' => 'invite', 'title' => $this->cal->gettext('sendinvitations')),
         $invite->show(1) . html::label('edit-attendees-invite', html::span('inner', $this->cal->gettext('sendinvitations'))));
     }
     $table->add_header('options', '');
 
     // hide invite column if disabled by config
     $itip_notify = (int)$this->rc->config->get('calendar_itip_send_option', $this->cal->defaults['calendar_itip_send_option']);
     if ($invitations && !($itip_notify & 2)) {
         $css = sprintf('#%s td.invite, #%s th.invite { display:none !important }', $attrib['id'], $attrib['id']);
         $this->rc->output->add_footer(html::tag('style', array('type' => 'text/css'), $css));
     }
 
     return $table->show($attrib);
   }
 
   /**
    *
    */
   function attendees_form($attrib = array())
   {
     $input    = new html_inputfield(array('name' => 'participant', 'id' => 'edit-attendee-name', 'class' => 'form-control'));
     $textarea = new html_textarea(array('name' => 'comment', 'id' => 'edit-attendees-comment', 'class' => 'form-control',
         'rows' => 4, 'cols' => 55, 'title' => $this->cal->gettext('itipcommenttitle')));
 
     return html::div($attrib,
       html::div('form-searchbar', $input->show() . " " .
         html::tag('input', array('type' => 'button', 'class' => 'button', 'id' => 'edit-attendee-add', 'value' => $this->cal->gettext('addattendee'))) . " " .
         html::tag('input', array('type' => 'button', 'class' => 'button', 'id' => 'edit-attendee-schedule', 'value' => $this->cal->gettext('scheduletime').'...'))) .
       html::p('attendees-commentbox', html::label('edit-attendees-comment', $this->cal->gettext('itipcomment')) . $textarea->show())
     );
   }
 
   /**
    *
    */
   function resources_form($attrib = array())
   {
     $input = new html_inputfield(array('name' => 'resource', 'id' => 'edit-resource-name', 'class' => 'form-control'));
 
     return html::div($attrib,
       html::div('form-searchbar', $input->show() . " " .
         html::tag('input', array('type' => 'button', 'class' => 'button', 'id' => 'edit-resource-add', 'value' => $this->cal->gettext('addresource'))) . " " .
         html::tag('input', array('type' => 'button', 'class' => 'button', 'id' => 'edit-resource-find', 'value' => $this->cal->gettext('findresources').'...')))
       );
   }
 
   /**
    *
    */
   function resources_list($attrib = array())
   {
     $attrib += array('id' => 'calendar-resources-list');
 
     $this->rc->output->add_gui_object('resourceslist', $attrib['id']);
 
     return html::tag('ul', $attrib, '', html::$common_attrib);
   }
 
   /**
    *
    */
   public function resource_info($attrib = array())
   {
     $attrib += array('id' => 'calendar-resources-info');
 
     $this->rc->output->add_gui_object('resourceinfo', $attrib['id']);
     $this->rc->output->add_gui_object('resourceownerinfo', $attrib['id'] . '-owner');
 
     // copy address book labels for owner details to client
     $this->rc->output->add_label('name','firstname','surname','department','jobtitle','email','phone','address');
 
     $table_attrib = array('id','class','style','width','summary','cellpadding','cellspacing','border');
 
     return html::tag('table', $attrib,
         html::tag('tbody', null, ''), $table_attrib) .
 
       html::tag('table', array('id' => $attrib['id'] . '-owner', 'style' => 'display:none') + $attrib,
         html::tag('thead', null,
           html::tag('tr', null,
             html::tag('td', array('colspan' => 2), rcube::Q($this->cal->gettext('resourceowner')))
           )
         ) .
         html::tag('tbody', null, ''),
         $table_attrib);
   }
 
   /**
    *
    */
   public function resource_calendar($attrib = array())
   {
     $attrib += array('id' => 'calendar-resources-calendar');
 
     $this->rc->output->add_gui_object('resourceinfocalendar', $attrib['id']);
 
     return html::div($attrib, '');
   }
 
   /**
    * GUI object 'searchform' for the resource finder dialog
    *
    * @param array Named parameters
    * @return string HTML code for the gui object
    */
   function resources_search_form($attrib)
   {
     $attrib += array(
         'command'       => 'search-resource',
         'reset-command' => 'reset-resource-search',
         'id'            => 'rcmcalresqsearchbox',
         'autocomplete'  => 'off',
         'form-name'     => 'rcmcalresoursqsearchform',
         'gui-object'    => 'resourcesearchform',
     );
 
     // add form tag around text field
     return $this->rc->output->search_form($attrib);
   }
 
   /**
    *
    */
   function attendees_freebusy_table($attrib = array())
   {
     $table = new html_table(array('cols' => 2, 'border' => 0, 'cellspacing' => 0));
     $table->add('attendees',
       html::tag('h3', 'boxtitle', $this->cal->gettext('tabattendees')) .
       html::div('timesheader', '&nbsp;') .
       html::div(array('id' => 'schedule-attendees-list', 'class' => 'attendees-list'), '')
     );
     $table->add('times',
       html::div('scroll',
         html::tag('table', array('id' => 'schedule-freebusy-times', 'border' => 0, 'cellspacing' => 0), html::tag('thead') . html::tag('tbody')) .
         html::div(array('id' => 'schedule-event-time', 'style' => 'display:none'), '&nbsp;')
       )
     );
     
     return $table->show($attrib);
   }
 
   /**
    *
    */
   function event_invitebox($attrib = array())
   {
     if ($this->cal->event) {
       return html::div($attrib,
         $this->cal->itip->itip_object_details_table($this->cal->event, $this->cal->itip->gettext('itipinvitation')) .
         $this->cal->invitestatus
       );
     }
     
     return '';
   }
 
   function event_rsvp_buttons($attrib = array())
   {
     $actions = array('accepted','tentative','declined');
     if ($attrib['delegate'] !== 'false')
       $actions[] = 'delegated';
 
     return $this->cal->itip->itip_rsvp_buttons($attrib, $actions);
   }
 
 }