/**
  * converts an iTIP event to a tine20 event
  * 
  * @param Calendar_Model_Event $_event
  * @param Calendar_Model_Event $_currentEvent (not iTIP!)
  */
 protected function _fromiTIP($_event, $_currentEvent)
 {
     if (!$_event->rrule) {
         $_event->exdate = NULL;
     }
     if ($_event->exdate instanceof Tinebase_Record_RecordSet) {
         try {
             $currExdates = $this->_eventController->getRecurExceptions($_event, TRUE);
             $this->getAlarms($currExdates);
             $currClientExdates = $this->_eventController->getRecurExceptions($_event, TRUE, $this->getEventFilter());
             $this->getAlarms($currClientExdates);
         } catch (Tinebase_Exception_NotFound $e) {
             $currExdates = NULL;
             $currClientExdates = NULL;
         }
         foreach ($_event->exdate as $idx => $exdate) {
             try {
                 $this->_prepareException($_event, $exdate);
             } catch (Exception $e) {
             }
             $currExdate = $currExdates instanceof Tinebase_Record_RecordSet ? $currExdates->filter('recurid', $exdate->recurid)->getFirstRecord() : NULL;
             if ($exdate->is_deleted) {
                 // reset implicit filter fallouts and mark as don't touch (seq = -1)
                 $currClientExdate = $currClientExdates instanceof Tinebase_Record_RecordSet ? $currClientExdates->filter('recurid', $exdate->recurid)->getFirstRecord() : NULL;
                 if ($currClientExdate && $currClientExdate->is_deleted) {
                     $_event->exdate[$idx] = $currExdate;
                     $currExdate->seq = -1;
                     continue;
                 }
             }
             $this->_fromiTIP($exdate, $currExdate ? $currExdate : clone $_currentEvent);
         }
     }
     // assert organizer
     $_event->organizer = $_event->organizer ?: ($_currentEvent->organizer ?: $this->_calendarUser->user_id);
     $this->_addAttendeeWithoutEmail($_event, $_currentEvent);
     $CUAttendee = Calendar_Model_Attender::getAttendee($_event->attendee, $this->_calendarUser);
     $currentCUAttendee = Calendar_Model_Attender::getAttendee($_currentEvent->attendee, $this->_calendarUser);
     $isOrganizer = $_event->isOrganizer($this->_calendarUser);
     // remove perspective
     if ($CUAttendee && !$isOrganizer) {
         $CUAttendee->transp = $_event->transp;
         $_event->transp = $_currentEvent->transp ? $_currentEvent->transp : $_event->transp;
     }
     // apply changes to original alarms
     $_currentEvent->alarms = $_currentEvent->alarms instanceof Tinebase_Record_RecordSet ? $_currentEvent->alarms : new Tinebase_Record_RecordSet('Tinebase_Model_Alarm');
     $_event->alarms = $_event->alarms instanceof Tinebase_Record_RecordSet ? $_event->alarms : new Tinebase_Record_RecordSet('Tinebase_Model_Alarm');
     foreach ($_currentEvent->alarms as $currentAlarm) {
         if (Calendar_Model_Attender::isAlarmForAttendee($this->_calendarUser, $currentAlarm)) {
             $alarmUpdate = Calendar_Controller_Alarm::getMatchingAlarm($_event->alarms, $currentAlarm);
             if ($alarmUpdate) {
                 // we could map the alarm => save ack & snooze options
                 if ($dtAck = Calendar_Controller_Alarm::getAcknowledgeTime($alarmUpdate)) {
                     Calendar_Controller_Alarm::setAcknowledgeTime($currentAlarm, $dtAck, $this->getCalendarUser()->user_id);
                 }
                 if ($dtSnooze = Calendar_Controller_Alarm::getSnoozeTime($alarmUpdate)) {
                     Calendar_Controller_Alarm::setSnoozeTime($currentAlarm, $dtSnooze, $this->getCalendarUser()->user_id);
                 }
                 $_event->alarms->removeRecord($alarmUpdate);
             } else {
                 // alarm is to be skiped/deleted
                 if (!$currentAlarm->getOption('attendee')) {
                     Calendar_Controller_Alarm::skipAlarm($currentAlarm, $this->_calendarUser);
                 } else {
                     $_currentEvent->alarms->removeRecord($currentAlarm);
                 }
             }
         }
     }
     if (!$isOrganizer) {
         $_event->alarms->setOption('attendee', Calendar_Controller_Alarm::attendeeToOption($this->_calendarUser));
     }
     $_event->alarms->merge($_currentEvent->alarms);
     // assert organizer for personal calendars to be calendar owner
     if ($this->_currentEventFacadeContainer && $this->_currentEventFacadeContainer->getId() == $_event->container_id && $this->_currentEventFacadeContainer->type == Tinebase_Model_Container::TYPE_PERSONAL && !$_event->hasExternalOrganizer()) {
         $_event->organizer = $this->_calendarUser->user_id;
     }
     // in MS world only cal_user can do status updates
     if ($CUAttendee) {
         $CUAttendee->status_authkey = $currentCUAttendee ? $currentCUAttendee->status_authkey : NULL;
     }
 }