--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/libcalendaring/lib/libcalendaring_itip.php	Sat Jan 13 08:57:56 2018 -0500
@@ -0,0 +1,867 @@
+<?php
+
+/**
+ * iTIP functions for the calendar-based Roudncube plugins
+ *
+ * Class providing functionality to manage iTIP invitations
+ *
+ * @author Thomas Bruederli <bruederli@kolabsys.com>
+ *
+ * Copyright (C) 2011-2014, 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 libcalendaring_itip
+{
+    protected $rc;
+    protected $lib;
+    protected $plugin;
+    protected $sender;
+    protected $domain;
+    protected $itip_send = false;
+    protected $rsvp_actions = array('accepted','tentative','declined','delegated');
+    protected $rsvp_status  = array('accepted','tentative','declined','delegated');
+
+    function __construct($plugin, $domain = 'libcalendaring')
+    {
+        $this->plugin = $plugin;
+        $this->rc = rcube::get_instance();
+        $this->lib = libcalendaring::get_instance();
+        $this->domain = $domain;
+
+        $hook = $this->rc->plugins->exec_hook('calendar_load_itip',
+            array('identity' => $this->rc->user->list_emails(true)));
+        $this->sender = $hook['identity'];
+
+        $this->plugin->add_hook('message_before_send', array($this, 'before_send_hook'));
+        $this->plugin->add_hook('smtp_connect', array($this, 'smtp_connect_hook'));
+    }
+
+    public function set_sender_email($email)
+    {
+        if (!empty($email))
+            $this->sender['email'] = $email;
+    }
+
+    public function set_rsvp_actions($actions)
+    {
+        $this->rsvp_actions = (array)$actions;
+        $this->rsvp_status = array_merge($this->rsvp_actions, array('delegated'));
+    }
+
+    public function set_rsvp_status($status)
+    {
+        $this->rsvp_status = $status;
+    }
+
+    /**
+     * Wrapper for rcube_plugin::gettext()
+     * Checking for a label in different domains
+     *
+     * @see rcube::gettext()
+     */
+    public function gettext($p)
+    {
+        $label = is_array($p) ? $p['name'] : $p;
+        $domain = $this->domain;
+        if (!$this->rc->text_exists($label, $domain)) {
+            $domain = 'libcalendaring';
+        }
+        return $this->rc->gettext($p, $domain);
+    }
+
+    /**
+     * Send an iTip mail message
+     *
+     * @param array   Event object to send
+     * @param string  iTip method (REQUEST|REPLY|CANCEL)
+     * @param array   Hash array with recipient data (name, email)
+     * @param string  Mail subject
+     * @param string  Mail body text label
+     * @param object  Mail_mime object with message data
+     * @param boolean Request RSVP
+     * @return boolean True on success, false on failure
+     */
+    public function send_itip_message($event, $method, $recipient, $subject, $bodytext, $message = null, $rsvp = true)
+    {
+        if (!$this->sender['name'])
+            $this->sender['name'] = $this->sender['email'];
+
+        if (!$message) {
+            libcalendaring::identify_recurrence_instance($event);
+            $message = $this->compose_itip_message($event, $method, $rsvp);
+        }
+
+        $mailto = rcube_utils::idn_to_ascii($recipient['email']);
+
+        $headers = $message->headers();
+        $headers['To'] = format_email_recipient($mailto, $recipient['name']);
+        $headers['Subject'] = $this->gettext(array(
+            'name' => $subject,
+            'vars' => array(
+                'title' => $event['title'],
+                'name' => $this->sender['name']
+            )
+        ));
+
+        // compose a list of all event attendees
+        $attendees_list = array();
+        foreach ((array)$event['attendees'] as $attendee) {
+            $attendees_list[] = ($attendee['name'] && $attendee['email']) ?
+                $attendee['name'] . ' <' . $attendee['email'] . '>' :
+                ($attendee['name'] ? $attendee['name'] : $attendee['email']);
+        }
+
+        $recurrence_info = '';
+        if (!empty($event['recurrence_id'])) {
+            $recurrence_info = "\n\n** " . $this->gettext($event['thisandfuture'] ? 'itipmessagefutureoccurrence' : 'itipmessagesingleoccurrence') . ' **';
+        }
+        else if (!empty($event['recurrence'])) {
+            $recurrence_info = sprintf("\n%s: %s", $this->gettext('recurring'), $this->lib->recurrence_text($event['recurrence']));
+        }
+
+        $mailbody = $this->gettext(array(
+            'name' => $bodytext,
+            'vars' => array(
+                'title' => $event['title'],
+                'date' => $this->lib->event_date_text($event, true) . $recurrence_info,
+                'attendees' => join(",\n ", $attendees_list),
+                'sender' => $this->sender['name'],
+                'organizer' => $this->sender['name'],
+            )
+        ));
+
+        // if (!empty($event['comment'])) {
+        //     $mailbody .= "\n\n" . $this->gettext('itipsendercomment') . $event['comment'];
+        // }
+
+        // append links for direct invitation replies
+        if ($method == 'REQUEST' && $rsvp && ($token = $this->store_invitation($event, $recipient['email']))) {
+            $mailbody .= "\n\n" . $this->gettext(array(
+                'name' => 'invitationattendlinks',
+                'vars' => array('url' => $this->plugin->get_url(array('action' => 'attend', 't' => $token))),
+            ));
+        }
+        else if ($method == 'CANCEL' && $event['cancelled']) {
+            $this->cancel_itip_invitation($event);
+        }
+
+        $message->headers($headers, true);
+        $message->setTXTBody(rcube_mime::format_flowed($mailbody, 79));
+
+        if ($this->rc->config->get('libcalendaring_itip_debug', false)) {
+            rcube::console('iTip ' . $method, $message->txtHeaders() . "\r\n" . $message->get());
+        }
+
+        // finally send the message
+        $this->itip_send = true;
+        $sent = $this->rc->deliver_message($message, $headers['X-Sender'], $mailto, $smtp_error);
+        $this->itip_send = false;
+
+        return $sent;
+    }
+
+    /**
+     * Plugin hook triggered by rcube::deliver_message() before delivering a message.
+     * Here we can set the 'smtp_server' config option to '' in order to use
+     * PHP's mail() function for unauthenticated email sending.
+     */
+    public function before_send_hook($p)
+    {
+        if ($this->itip_send && !$this->rc->user->ID && $this->rc->config->get('calendar_itip_smtp_server', null) === '') {
+            $this->rc->config->set('smtp_server', '');
+        }
+
+        return $p;
+    }
+
+    /**
+     * Plugin hook to alter SMTP authentication.
+     * This is used if iTip messages are to be sent from an unauthenticated session
+     */
+    public function smtp_connect_hook($p)
+    {
+        // replace smtp auth settings if we're not in an authenticated session
+        if ($this->itip_send && !$this->rc->user->ID) {
+            foreach (array('smtp_server', 'smtp_user', 'smtp_pass') as $prop) {
+                $p[$prop] = $this->rc->config->get("calendar_itip_$prop", $p[$prop]);
+            }
+        }
+
+      return $p;
+    }
+
+    /**
+     * Helper function to build a Mail_mime object to send an iTip message
+     *
+     * @param array   Event object to send
+     * @param string  iTip method (REQUEST|REPLY|CANCEL)
+     * @param boolean Request RSVP
+     * @return object Mail_mime object with message data
+     */
+    public function compose_itip_message($event, $method, $rsvp = true)
+    {
+        $from     = rcube_utils::idn_to_ascii($this->sender['email']);
+        $from_utf = rcube_utils::idn_to_utf8($from);
+        $sender   = format_email_recipient($from, $this->sender['name']);
+
+        // truncate list attendees down to the recipient of the iTip Reply.
+        // constraints for a METHOD:REPLY according to RFC 5546
+        if ($method == 'REPLY') {
+            $replying_attendee = null;
+            $reply_attendees = array();
+            foreach ($event['attendees'] as $attendee) {
+                if ($attendee['role'] == 'ORGANIZER') {
+                    $reply_attendees[] = $attendee;
+                }
+                else if (strcasecmp($attendee['email'], $from) == 0 || strcasecmp($attendee['email'], $from_utf) == 0) {
+                    $replying_attendee = $attendee;
+                    if ($attendee['status'] != 'DELEGATED') {
+                        unset($replying_attendee['rsvp']);  // unset the RSVP attribute
+                    }
+                }
+                // include attendees relevant for delegation (RFC 5546, Section 4.2.5)
+                else if ((!empty($attendee['delegated-to']) &&
+                            (strcasecmp($attendee['delegated-to'], $from) == 0 || strcasecmp($attendee['delegated-to'], $from_utf) == 0)) ||
+                         (!empty($attendee['delegated-from']) &&
+                            (strcasecmp($attendee['delegated-from'], $from) == 0 || strcasecmp($attendee['delegated-from'], $from_utf) == 0))) {
+                    $reply_attendees[] = $attendee;
+                }
+            }
+            if ($replying_attendee) {
+                array_unshift($reply_attendees, $replying_attendee);
+                $event['attendees'] = $reply_attendees;
+            }
+            if ($event['recurrence']) {
+                unset($event['recurrence']['EXCEPTIONS']);
+            }
+        }
+        // set RSVP for every attendee
+        else if ($method == 'REQUEST') {
+            foreach ($event['attendees'] as $i => $attendee) {
+                if (($rsvp || !isset($attendee['rsvp'])) && ($attendee['status'] != 'DELEGATED' && $attendee['role'] != 'NON-PARTICIPANT')) {
+                    $event['attendees'][$i]['rsvp']= (bool)$rsvp;
+                }
+            }
+        }
+        else if ($method == 'CANCEL') {
+            if ($event['recurrence']) {
+                unset($event['recurrence']['EXCEPTIONS']);
+            }
+        }
+
+        // Set SENT-BY property if the sender is not the organizer
+        if ($method == 'CANCEL' || $method == 'REQUEST') {
+            foreach ((array)$event['attendees'] as $idx => $attendee) {
+                if ($attendee['role'] == 'ORGANIZER'
+                    && $attendee['email']
+                    && strcasecmp($attendee['email'], $from) != 0
+                    && strcasecmp($attendee['email'], $from_utf) != 0
+                ) {
+                    $attendee['sent-by'] = 'mailto:' . $from_utf;
+                    $event['organizer'] = $event['attendees'][$idx] = $attendee;
+                    break;
+                }
+            }
+        }
+
+        // compose multipart message using PEAR:Mail_Mime
+        $message = new Mail_mime("\r\n");
+        $message->setParam('text_encoding', 'quoted-printable');
+        $message->setParam('head_encoding', 'quoted-printable');
+        $message->setParam('head_charset', RCUBE_CHARSET);
+        $message->setParam('text_charset', RCUBE_CHARSET . ";\r\n format=flowed");
+        $message->setContentType('multipart/alternative');
+
+        // compose common headers array
+        $headers = array(
+            'From' => $sender,
+            'Date' => $this->rc->user_date(),
+            'Message-ID' => $this->rc->gen_message_id(),
+            'X-Sender' => $from,
+        );
+        if ($agent = $this->rc->config->get('useragent')) {
+            $headers['User-Agent'] = $agent;
+        }
+
+        $message->headers($headers);
+
+        // attach ics file for this event
+        $ical = libcalendaring::get_ical();
+        $ics = $ical->export(array($event), $method, false, $method == 'REQUEST' && $this->plugin->driver ? array($this->plugin->driver, 'get_attachment_body') : false);
+        $filename = $event['_type'] == 'task' ? 'todo.ics' : 'event.ics';
+        $message->addAttachment($ics, 'text/calendar', $filename, false, '8bit', '', RCUBE_CHARSET . "; method=" . $method);
+
+        return $message;
+    }
+
+    /**
+     * Forward the given iTip event as delegation to another person
+     *
+     * @param array Event object to delegate
+     * @param mixed Delegatee as string or hash array with keys 'name' and 'mailto'
+     * @param boolean The delegator's RSVP flag
+     * @param array List with indexes of new/updated attendees
+     * @return boolean True on success, False on failure
+     */
+    public function delegate_to(&$event, $delegate, $rsvp = false, &$attendees = array())
+    {
+        if (is_string($delegate)) {
+            $delegates = rcube_mime::decode_address_list($delegate, 1, false);
+            if (count($delegates) > 0) {
+                $delegate = reset($delegates);
+            }
+        }
+
+        $emails = $this->lib->get_user_emails();
+        $me     = $this->rc->user->list_emails(true);
+
+        // find/create the delegate attendee
+        $delegate_attendee = array(
+            'email' => $delegate['mailto'],
+            'name'  => $delegate['name'],
+            'role'  => 'REQ-PARTICIPANT',
+        );
+        $delegate_index = count($event['attendees']);
+
+        foreach ($event['attendees'] as $i => $attendee) {
+          // set myself the DELEGATED-TO parameter
+          if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
+              $event['attendees'][$i]['delegated-to'] = $delegate['mailto'];
+              $event['attendees'][$i]['status'] = 'DELEGATED';
+              $event['attendees'][$i]['role'] = 'NON-PARTICIPANT';
+              $event['attendees'][$i]['rsvp'] = $rsvp;
+
+              $me['email'] = $attendee['email'];
+              $delegate_attendee['role'] = $attendee['role'];
+          }
+          // the disired delegatee is already listed as an attendee
+          else if (stripos($delegate['mailto'], $attendee['email']) !== false && $attendee['role'] != 'ORGANIZER') {
+              $delegate_attendee = $attendee;
+              $delegate_index = $i;
+              break;
+          }
+          // TODO: remove previous delegatee (i.e. attendee that has DELEGATED-FROM == $me)
+        }
+
+        // set/add delegate attendee with RSVP=TRUE and DELEGATED-FROM parameter
+        $delegate_attendee['rsvp'] = true;
+        $delegate_attendee['status'] = 'NEEDS-ACTION';
+        $delegate_attendee['delegated-from'] = $me['email'];
+        $event['attendees'][$delegate_index] = $delegate_attendee;
+
+        $attendees[] = $delegate_index;
+
+        $this->set_sender_email($me['email']);
+        return $this->send_itip_message($event, 'REQUEST', $delegate_attendee, 'itipsubjectdelegatedto', 'itipmailbodydelegatedto');
+    }
+
+    /**
+     * Handler for calendar/itip-status requests
+     */
+    public function get_itip_status($event, $existing = null)
+    {
+      $action = $event['rsvp'] ? 'rsvp' : '';
+      $status = $event['fallback'];
+      $latest = $resheduled = false;
+      $html   = '';
+
+      if (is_numeric($event['changed']))
+        $event['changed'] = new DateTime('@'.$event['changed']);
+
+      // check if the given itip object matches the last state
+      if ($existing) {
+        $latest = (isset($event['sequence']) && intval($existing['sequence']) == intval($event['sequence'])) ||
+                  (!isset($event['sequence']) && $existing['changed'] && $existing['changed'] >= $event['changed']);
+      }
+
+      // determine action for REQUEST
+      if ($event['method'] == 'REQUEST') {
+        $html = html::div('rsvp-status', $this->gettext('acceptinvitation'));
+
+        if ($existing) {
+          $rsvp = $event['rsvp'];
+          $emails = $this->lib->get_user_emails();
+          foreach ($existing['attendees'] as $attendee) {
+            if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
+              $status = strtoupper($attendee['status']);
+              break;
+            }
+          }
+
+          // Detect re-sheduling
+          if (!$latest) {
+            // FIXME: This is probably to simplistic, or maybe we should just check
+            //        attendee's RSVP flag in the new event?
+            $resheduled = $existing['start'] != $event['start'] || $existing['end'] > $event['end'];
+          }
+        }
+        else {
+          $rsvp = $event['rsvp'] && $this->rc->config->get('calendar_allow_itip_uninvited', true);
+        }
+
+        $status_lc = strtolower($status);
+
+        if ($status_lc == 'unknown' && !$this->rc->config->get('calendar_allow_itip_uninvited', true)) {
+          $html = html::div('rsvp-status', $this->gettext('notanattendee'));
+          $action = 'import';
+        }
+        else if (in_array($status_lc, $this->rsvp_status)) {
+          $status_text = $this->gettext(($latest ? 'youhave' : 'youhavepreviously') . $status_lc);
+
+          if ($existing && ($existing['sequence'] > $event['sequence'] || (!isset($event['sequence']) && $existing['changed'] && $existing['changed'] > $event['changed']))) {
+            $action = '';  // nothing to do here, outdated invitation
+            if ($status_lc == 'needs-action')
+              $status_text = $this->gettext('outdatedinvitation');
+          }
+          else if (!$existing && !$rsvp) {
+            $action = 'import';
+          }
+          else if ($resheduled) {
+            $action = 'rsvp';
+          }
+          else if ($status_lc != 'needs-action') {
+            $action = !$latest ? 'update' : '';
+          }
+
+          $html = html::div('rsvp-status ' . $status_lc, $status_text);
+        }
+      }
+      // determine action for REPLY
+      else if ($event['method'] == 'REPLY') {
+        // check whether the sender already is an attendee
+        if ($existing) {
+          $action = $this->rc->config->get('calendar_allow_itip_uninvited', true) ? 'accept' : '';
+          $listed = false;
+          foreach ($existing['attendees'] as $attendee) {
+            if ($attendee['role'] != 'ORGANIZER' && strcasecmp($attendee['email'], $event['attendee']) == 0) {
+              $status_lc = strtolower($status);
+              if (in_array($status_lc, $this->rsvp_status)) {
+                $html = html::div('rsvp-status ' . $status_lc, $this->gettext(array(
+                    'name' => 'attendee' . $status_lc,
+                    'vars' => array(
+                        'delegatedto' => rcube::Q($event['delegated-to'] ?: ($attendee['delegated-to'] ?: '?')),
+                    )
+                )));
+              }
+              $action = $attendee['status'] == $status || !$latest ? '' : 'update';
+              $listed = true;
+              break;
+            }
+          }
+
+          if (!$listed) {
+            $html = html::div('rsvp-status', $this->gettext('itipnewattendee'));
+          }
+        }
+        else {
+          $html = html::div('rsvp-status hint', $this->gettext('itipobjectnotfound'));
+          $action = '';
+        }
+      }
+      else if ($event['method'] == 'CANCEL') {
+        if (!$existing) {
+          $html = html::div('rsvp-status hint', $this->gettext('itipobjectnotfound'));
+          $action = '';
+        }
+      }
+
+      return array(
+          'uid'        => $event['uid'],
+          'id'         => asciiwords($event['uid'], true),
+          'existing'   => $existing ? true : false,
+          'saved'      => $existing ? true : false,
+          'latest'     => $latest,
+          'status'     => $status,
+          'action'     => $action,
+          'resheduled' => $resheduled,
+          'html'       => $html,
+      );
+    }
+
+    /**
+     * Build inline UI elements for iTip messages
+     */
+    public function mail_itip_inline_ui($event, $method, $mime_id, $task, $message_date = null, $preview_url = null)
+    {
+        $buttons = array();
+        $dom_id = asciiwords($event['uid'], true);
+        $rsvp_status = 'unknown';
+
+        // pass some metadata about the event and trigger the asynchronous status check
+        $changed = is_object($event['changed']) ? $event['changed'] : $message_date;
+        $metadata = array(
+            'uid'      => $event['uid'],
+            '_instance' => $event['_instance'],
+            'changed'  => $changed ? $changed->format('U') : 0,
+            'sequence' => intval($event['sequence']),
+            'method'   => $method,
+            'task'     => $task,
+        );
+
+        // create buttons to be activated from async request checking existence of this event in local calendars
+        $buttons[] = html::div(array('id' => 'loading-'.$dom_id, 'class' => 'rsvp-status loading'), $this->gettext('loading'));
+
+        // on iTip REPLY we have two options:
+        if ($method == 'REPLY') {
+            $title = $this->gettext('itipreply');
+
+            foreach ($event['attendees'] as $attendee) {
+                if (!empty($attendee['email']) && $attendee['role'] != 'ORGANIZER') {
+                    if (empty($event['_sender']) || self::compare_email($attendee['email'], $event['_sender'], $event['_sender_utf'])) {
+                        $metadata['attendee'] = $attendee['email'];
+                        $rsvp_status = strtoupper($attendee['status']);
+                        if ($attendee['delegated-to']) {
+                            $metadata['delegated-to'] = $attendee['delegated-to'];
+                        }
+                        break;
+                    }
+                }
+            }
+
+            // 1. update the attendee status on our copy
+            $update_button = html::tag('input', array(
+                'type' => 'button',
+                'class' => 'button',
+                'onclick' => "rcube_libcalendaring.add_from_itip_mail('" . rcube::JQ($mime_id) . "', '$task')",
+                'value' => $this->gettext('updateattendeestatus'),
+            ));
+
+            // 2. accept or decline a new or delegate attendee
+            $accept_buttons = html::tag('input', array(
+                'type' => 'button',
+                'class' => "button accept",
+                'onclick' => "rcube_libcalendaring.add_from_itip_mail('" . rcube::JQ($mime_id) . "', '$task')",
+                'value' => $this->gettext('acceptattendee'),
+            ));
+            $accept_buttons .= html::tag('input', array(
+                'type' => 'button',
+                'class' => "button decline",
+                'onclick' => "rcube_libcalendaring.decline_attendee_reply('" . rcube::JQ($mime_id) . "', '$task')",
+                'value' => $this->gettext('declineattendee'),
+            ));
+
+            $buttons[] = html::div(array('id' => 'update-'.$dom_id, 'style' => 'display:none'), $update_button);
+            $buttons[] = html::div(array('id' => 'accept-'.$dom_id, 'style' => 'display:none'), $accept_buttons);
+        }
+        // when receiving iTip REQUEST messages:
+        else if ($method == 'REQUEST') {
+            $emails = $this->lib->get_user_emails();
+            $title = $event['sequence'] > 0 ? $this->gettext('itipupdate') : $this->gettext('itipinvitation');
+            $metadata['rsvp'] = true;
+            $metadata['sensitivity'] = $event['sensitivity'];
+
+            if (is_object($event['start'])) {
+                $metadata['date'] = $event['start']->format('U');
+            }
+
+            // check for X-KOLAB-INVITATIONTYPE property and only show accept/decline buttons
+            if (self::get_custom_property($event, 'X-KOLAB-INVITATIONTYPE') == 'CONFIRMATION') {
+                $this->rsvp_actions = array('accepted','declined');
+                $metadata['nosave'] = true;
+            }
+
+            // 1. display RSVP buttons (if the user was invited)
+            foreach ($this->rsvp_actions as $method) {
+                $rsvp_buttons .= html::tag('input', array(
+                    'type' => 'button',
+                    'class' => "button $method",
+                    'onclick' => "rcube_libcalendaring.add_from_itip_mail('" . rcube::JQ($mime_id) . "', '$task', '$method', '$dom_id')",
+                    'value' => $this->gettext('itip' . $method),
+                ));
+            }
+
+            // add button to open calendar/preview
+            if (!empty($preview_url)) {
+              $msgref = $this->lib->ical_message->folder . '/' . $this->lib->ical_message->uid . '#' . $mime_id;
+              $rsvp_buttons .= html::tag('input', array(
+                  'type' => 'button',
+                  'class' => "button preview",
+                  'onclick' => "rcube_libcalendaring.open_itip_preview('" . rcube::JQ($preview_url) . "', '" . rcube::JQ($msgref) . "')",
+                  'value' => $this->gettext('openpreview'),
+              ));
+            }
+
+            // 2. update the local copy with minor changes
+            $update_button = html::tag('input', array(
+                'type' => 'button',
+                'class' => 'button',
+                'onclick' => "rcube_libcalendaring.add_from_itip_mail('" . rcube::JQ($mime_id) . "', '$task')",
+                'value' => $this->gettext('updatemycopy'),
+            ));
+
+            // 3. Simply import the event without replying
+            $import_button = html::tag('input', array(
+                'type' => 'button',
+                'class' => 'button',
+                'onclick' => "rcube_libcalendaring.add_from_itip_mail('" . rcube::JQ($mime_id) . "', '$task')",
+                'value' => $this->gettext('importtocalendar'),
+            ));
+
+            // check my status
+            foreach ($event['attendees'] as $attendee) {
+                if ($attendee['email'] && in_array(strtolower($attendee['email']), $emails)) {
+                    $metadata['attendee'] = $attendee['email'];
+                    $metadata['rsvp'] = $attendee['rsvp'] || $attendee['role'] != 'NON-PARTICIPANT';
+                    $rsvp_status = !empty($attendee['status']) ? strtoupper($attendee['status']) : 'NEEDS-ACTION';
+                    break;
+                }
+            }
+
+            // add itip reply message controls
+            $rsvp_buttons .= html::div('itip-reply-controls', $this->itip_rsvp_options_ui($dom_id, $metadata['nosave']));
+
+            $buttons[] = html::div(array('id' => 'rsvp-'.$dom_id, 'class' => 'rsvp-buttons', 'style' => 'display:none'), $rsvp_buttons);
+            $buttons[] = html::div(array('id' => 'update-'.$dom_id, 'style' => 'display:none'), $update_button);
+
+            // prepare autocompletion for delegation dialog
+            if (in_array('delegated', $this->rsvp_actions)) {
+                $this->rc->autocomplete_init();
+            }
+        }
+        // for CANCEL messages, we can:
+        else if ($method == 'CANCEL') {
+            $title = $this->gettext('itipcancellation');
+            $event_prop = array_filter(array(
+              'uid' => $event['uid'],
+              '_instance' => $event['_instance'],
+              '_savemode' => $event['_savemode'],
+            ));
+
+            // 1. remove the event from our calendar
+            $button_remove = html::tag('input', array(
+                'type' => 'button',
+                'class' => 'button',
+                'onclick' => "rcube_libcalendaring.remove_from_itip(" . rcube_output::json_serialize($event_prop) . ", '$task', '" . rcube::JQ($event['title']) . "')",
+                'value' => $this->gettext('removefromcalendar'),
+            ));
+
+            // 2. update our copy with status=cancelled
+            $button_update = html::tag('input', array(
+              'type' => 'button',
+              'class' => 'button',
+              'onclick' => "rcube_libcalendaring.add_from_itip_mail('" . rcube::JQ($mime_id) . "', '$task')",
+              'value' => $this->gettext('updatemycopy'),
+            ));
+
+            $buttons[] = html::div(array('id' => 'rsvp-'.$dom_id, 'style' => 'display:none'), $button_remove . $button_update);
+
+            $rsvp_status = 'CANCELLED';
+            $metadata['rsvp'] = true;
+        }
+
+        // append generic import button
+        if ($import_button) {
+            $buttons[] = html::div(array('id' => 'import-'.$dom_id, 'style' => 'display:none'), $import_button);
+        }
+
+        // pass some metadata about the event and trigger the asynchronous status check
+        $metadata['fallback'] = $rsvp_status;
+        $metadata['rsvp'] = intval($metadata['rsvp']);
+
+        $this->rc->output->add_script("rcube_libcalendaring.fetch_itip_object_status(" . rcube_output::json_serialize($metadata) . ")", 'docready');
+
+        // get localized texts from the right domain
+        foreach (array('savingdata','deleteobjectconfirm','declinedeleteconfirm','declineattendee',
+            'cancel','itipdelegated','declineattendeeconfirm','itipcomment','delegateinvitation',
+            'delegateto','delegatersvpme','delegateinvalidaddress') as $label) {
+          $this->rc->output->command('add_label', "itip.$label", $this->gettext($label));
+        }
+
+        // show event details with buttons
+        return $this->itip_object_details_table($event, $title) .
+            html::div(array('class' => 'itip-buttons', 'id' => 'itip-buttons-' . asciiwords($metadata['uid'], true)), join('', $buttons));
+    }
+
+    /**
+     * Render an RSVP UI widget with buttons to respond on iTip invitations
+     */
+    function itip_rsvp_buttons($attrib = array(), $actions = null)
+    {
+        $attrib += array('type' => 'button');
+
+        if (!$actions)
+            $actions = $this->rsvp_actions;
+
+        foreach ($actions as $method) {
+            $buttons .= html::tag('input', array(
+                'type'  => $attrib['type'],
+                'name'  => $attrib['iname'],
+                'class' => 'button',
+                'rel'   => $method,
+                'value' => $this->gettext('itip' . $method),
+            ));
+        }
+
+        // add localized texts for the delegation dialog
+        if (in_array('delegated', $actions)) {
+            foreach (array('itipdelegated','itipcomment','delegateinvitation',
+                  'delegateto','delegatersvpme','delegateinvalidaddress','cancel') as $label) {
+                $this->rc->output->command('add_label', "itip.$label", $this->gettext($label));
+            }
+        }
+
+        foreach (array('all','current','future') as $mode) {
+            $this->rc->output->command('add_label', "rsvpmode$mode", $this->gettext("rsvpmode$mode"));
+        }
+
+        $savemode_radio = new html_radiobutton(array('name' => '_rsvpmode', 'class' => 'rsvp-replymode'));
+
+        return html::div($attrib,
+            html::div('label', $this->gettext('acceptinvitation')) .
+            html::div('rsvp-buttons',
+                $buttons .
+                html::div('itip-reply-controls', $this->itip_rsvp_options_ui($attrib['id']))
+            )
+        );
+    }
+
+    /**
+     * Render UI elements to control iTip reply message sending
+     */
+    public function itip_rsvp_options_ui($dom_id, $disable = false)
+    {
+        $itip_sending = $this->rc->config->get('calendar_itip_send_option', 3);
+
+        // itip sending is entirely disabled
+        if ($itip_sending === 0) {
+            return '';
+        }
+        // add checkbox to suppress itip reply message
+        else if ($itip_sending >= 2) {
+            $rsvp_additions = html::label(array('class' => 'noreply-toggle'),
+                html::tag('input', array('type' => 'checkbox', 'id' => 'noreply-'.$dom_id, 'value' => 1, 'disabled' => $disable, 'checked' => ($itip_sending & 1) == 0))
+                . ' ' . $this->gettext('itipsuppressreply')
+            );
+        }
+
+        // add input field for reply comment
+        $toggle_attrib = array(
+            'href'    => '#toggle',
+            'class'   => 'reply-comment-toggle',
+            'onclick' => '$(this).hide().parent().find(\'textarea\').show().focus()'
+        );
+        $textarea_attrib = array(
+            'id'    => 'reply-comment-' . $dom_id,
+            'name'  => '_comment',
+            'cols'  => 40,
+            'rows'  => 6,
+            'style' => 'display:none',
+            'placeholder' => $this->gettext('itipcomment')
+        );
+
+        $rsvp_additions .= html::a($toggle_attrib, $this->gettext('itipeditresponse'))
+            . html::div('itip-reply-comment', html::tag('textarea', $textarea_attrib, ''));
+
+        return $rsvp_additions;
+    }
+
+    /**
+     * Render event/task details in a table
+     */
+    function itip_object_details_table($event, $title)
+    {
+        $table = new html_table(array('cols' => 2, 'border' => 0, 'class' => 'calendar-eventdetails'));
+        $table->add('ititle', $title);
+        $table->add('title', rcube::Q($event['title']));
+        if ($event['start'] && $event['end']) {
+            $table->add('label', $this->gettext('date'));
+            $table->add('date', rcube::Q($this->lib->event_date_text($event)));
+        }
+        else if ($event['due'] && $event['_type'] == 'task') {
+            $table->add('label', $this->gettext('date'));
+            $table->add('date', rcube::Q($this->lib->event_date_text($event)));
+        }
+        if (!empty($event['recurrence_date'])) {
+            $table->add('label', '');
+            $table->add('recurrence-id', $this->gettext($event['thisandfuture'] ? 'itipfutureoccurrence' : 'itipsingleoccurrence'));
+        }
+        else if (!empty($event['recurrence'])) {
+            $table->add('label', $this->gettext('recurring'));
+            $table->add('recurrence', $this->lib->recurrence_text($event['recurrence']));
+        }
+        if ($event['location']) {
+            $table->add('label', $this->gettext('location'));
+            $table->add('location', rcube::Q($event['location']));
+        }
+        if ($event['sensitivity'] && $event['sensitivity'] != 'public') {
+            $table->add('label', $this->gettext('sensitivity'));
+            $table->add('sensitivity', ucfirst($this->gettext($event['sensitivity'])) . '!');
+        }
+        if ($event['status'] == 'COMPLETED' || $event['status'] == 'CANCELLED') {
+            $table->add('label', $this->gettext('status'));
+            $table->add('status', $this->gettext('status-' . strtolower($event['status'])));
+        }
+        if ($event['comment']) {
+            $table->add('label', $this->gettext('comment'));
+            $table->add('location', rcube::Q($event['comment']));
+        }
+
+        return $table->show();
+    }
+
+
+    /**
+     * Create iTIP invitation token for later replies via URL
+     *
+     * @param array Hash array with event properties
+     * @param string Attendee email address
+     * @return string Invitation token
+     */
+    public function store_invitation($event, $attendee)
+    {
+        // empty stub
+        return false;
+    }
+
+    /**
+     * Mark invitations for the given event as cancelled
+     *
+     * @param array Hash array with event properties
+     */
+    public function cancel_itip_invitation($event)
+    {
+        // empty stub
+        return false;
+    }
+
+    /**
+     * Utility function to get the value of a custom property
+     */
+    public static function get_custom_property($event, $name)
+    {
+      $ret = false;
+
+      if (is_array($event['x-custom'])) {
+          array_walk($event['x-custom'], function($prop, $i) use ($name, &$ret) {
+              if (strcasecmp($prop[0], $name) === 0) {
+                  $ret = $prop[1];
+              }
+          });
+      }
+
+      return $ret;
+    }
+
+    /**
+     * Compare email address
+     */
+    public static function compare_email($value, $email, $email_utf = null)
+    {
+        $v1 = !empty($email) && strcasecmp($value, $email) === 0;
+        $v2 = !empty($email_utf) && strcasecmp($value, $email_utf) === 0;
+
+        return $v1 || $v2;
+    }
+}