--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/calendar/lib/calendar_itip.php	Sat Jan 13 08:56:12 2018 -0500
@@ -0,0 +1,240 @@
+<?php
+
+require_once realpath(__DIR__ . '/../../libcalendaring/lib/libcalendaring_itip.php');
+
+/**
+ * iTIP functions for the Calendar plugin
+ *
+ * Class providing functionality to manage iTIP invitations
+ *
+ * @version @package_version@
+ * @author Thomas Bruederli <bruederli@kolabsys.com>
+ * @package @package_name@
+ *
+ * Copyright (C) 2011, 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_itip extends libcalendaring_itip
+{
+  /**
+   * Constructor to set text domain to calendar
+   */
+  function __construct($plugin, $domain = 'calendar')
+  {
+    parent::__construct($plugin, $domain);
+
+    $this->db_itipinvitations = $this->rc->db->table_name('itipinvitations', true);
+  }
+
+  /**
+   * Handler for calendar/itip-status requests
+   */
+  public function get_itip_status($event, $existing = null)
+  {
+    $status = parent::get_itip_status($event, $existing);
+
+    // don't ask for deleting events when declining
+    if ($this->rc->config->get('kolab_invitation_calendars'))
+      $status['saved'] = false;
+
+    return $status;
+  }
+
+  /**
+   * Find invitation record by token
+   *
+   * @param string Invitation token
+   * @return mixed Invitation record as hash array or False if not found
+   */
+  public function get_invitation($token)
+  {
+    if ($parts = $this->decode_token($token)) {
+      $result = $this->rc->db->query("SELECT * FROM $this->db_itipinvitations WHERE `token` = ?", $parts['base']);
+      if ($result && ($rec = $this->rc->db->fetch_assoc($result))) {
+        $rec['event'] = unserialize($rec['event']);
+        $rec['attendee'] = $parts['attendee'];
+        return $rec;
+      }
+    }
+    
+    return false;
+  }
+
+  /**
+   * Update the attendee status of the given invitation record
+   *
+   * @param array Invitation record as fetched with calendar_itip::get_invitation()
+   * @param string Attendee email address
+   * @param string New attendee status
+   */
+  public function update_invitation($invitation, $email, $newstatus)
+  {
+    if (is_string($invitation))
+      $invitation = $this->get_invitation($invitation);
+    
+    if ($invitation['token'] && $invitation['event']) {
+      // update attendee record in event data
+      foreach ($invitation['event']['attendees'] as $i => $attendee) {
+        if ($attendee['role'] == 'ORGANIZER') {
+          $organizer = $attendee;
+        }
+        else if ($attendee['email'] == $email) {
+          // nothing to be done here
+          if ($attendee['status'] == $newstatus)
+            return true;
+          
+          $invitation['event']['attendees'][$i]['status'] = $newstatus;
+          $this->sender = $attendee;
+        }
+      }
+      $invitation['event']['changed'] = new DateTime();
+      
+      // send iTIP REPLY message to organizer
+      if ($organizer) {
+        $status = strtolower($newstatus);
+        if ($this->send_itip_message($invitation['event'], 'REPLY', $organizer, 'itipsubject' . $status, 'itipmailbody' . $status))
+          $this->rc->output->command('display_message', $this->plugin->gettext(array('name' => 'sentresponseto', 'vars' => array('mailto' => $organizer['name'] ? $organizer['name'] : $organizer['email']))), 'confirmation');
+        else
+          $this->rc->output->command('display_message', $this->plugin->gettext('itipresponseerror'), 'error');
+      }
+      
+      // update record in DB
+      $query = $this->rc->db->query(
+        "UPDATE $this->db_itipinvitations
+         SET `event` = ?
+         WHERE `token` = ?",
+        self::serialize_event($invitation['event']),
+        $invitation['token']
+      );
+
+      if ($this->rc->db->affected_rows($query))
+        return true;
+    }
+    
+    return false;
+  }
+
+
+  /**
+   * Create iTIP invitation token for later replies via URL
+   *
+   * @param array Hash array with event properties
+   * @param string Attendee email address
+   * @return string Invitation token
+   */
+  public function store_invitation($event, $attendee)
+  {
+    static $stored = array();
+    
+    if (!$event['uid'] || !$attendee)
+      return false;
+      
+    // generate token for this invitation
+    $token = $this->generate_token($event, $attendee);
+    $base = substr($token, 0, 40);
+    
+    // already stored this
+    if ($stored[$base])
+      return $token;
+
+    // delete old entry
+    $this->rc->db->query("DELETE FROM $this->db_itipinvitations WHERE `token` = ?", $base);
+
+    $event_uid = $event['uid'] . ($event['_instance'] ? '-' . $event['_instance'] : '');
+
+    $query = $this->rc->db->query(
+      "INSERT INTO $this->db_itipinvitations
+       (`token`, `event_uid`, `user_id`, `event`, `expires`)
+       VALUES(?, ?, ?, ?, ?)",
+      $base,
+      $event_uid,
+      $this->rc->user->ID,
+      self::serialize_event($event),
+      date('Y-m-d H:i:s', $event['end']->format('U') + 86400 * 2)
+    );
+    
+    if ($this->rc->db->affected_rows($query)) {
+      $stored[$base] = 1;
+      return $token;
+    }
+    
+    return false;
+  }
+
+  /**
+   * Mark invitations for the given event as cancelled
+   *
+   * @param array Hash array with event properties
+   */
+  public function cancel_itip_invitation($event)
+  {
+    $event_uid = $event['uid'] . ($event['_instance'] ? '-' . $event['_instance'] : '');
+
+    // flag invitation record as cancelled
+    $this->rc->db->query(
+      "UPDATE $this->db_itipinvitations
+       SET `cancelled` = 1
+       WHERE `event_uid` = ? AND `user_id` = ?",
+       $event_uid,
+       $this->rc->user->ID
+    );
+  }
+
+  /**
+   * Generate an invitation request token for the given event and attendee
+   *
+   * @param array Event hash array
+   * @param string Attendee email address
+   */
+  public function generate_token($event, $attendee)
+  {
+    $event_uid = $event['uid'] . ($event['_instance'] ? '-' . $event['_instance'] : '');
+    $base = sha1($event_uid . ';' . $this->rc->user->ID);
+    $mail = base64_encode($attendee);
+    $hash = substr(md5($base . $mail . $this->rc->config->get('des_key')), 0, 6);
+    
+    return "$base.$mail.$hash";
+  }
+
+  /**
+   * Decode the given iTIP request token and return its parts
+   *
+   * @param string Request token to decode
+   * @return mixed Hash array with parts or False if invalid
+   */
+  public function decode_token($token)
+  {
+    list($base, $mail, $hash) = explode('.', $token);
+    
+    // validate and return parts
+    if ($mail && $hash && $hash == substr(md5($base . $mail . $this->rc->config->get('des_key')), 0, 6)) {
+      return array('base' => $base, 'attendee' => base64_decode($mail));
+    }
+    
+    return false;
+  }
+
+  /**
+   * Helper method to serialize the given event for storing in invitations table
+   */
+  private static function serialize_event($event)
+  {
+    $ev = $event;
+    $ev['description'] = abbreviate_string($ev['description'], 100);
+    unset($ev['attachments']);
+    return serialize($ev);
+  }
+
+}