<?php
  /**
   * PHP OpenCloud library.
   * 
   * @copyright 2014 Rackspace Hosting, Inc. See LICENSE for information.
   * @license   https://www.apache.org/licenses/LICENSE-2.0
   * @author    Glen Campbell <glen.campbell@rackspace.com>
   * @author    Jamie Hannaford <jamie.hannaford@rackspace.com>
   */
  
  namespace OpenCloud\Compute\Resource;
  
  use OpenCloud\Common\Lang;
  use OpenCloud\Common\Exceptions;
  use OpenCloud\Common\PersistentObject;
  
  /**
   * The VolumeAttachment class represents a volume that is attached to a server.
   */
  class VolumeAttachment extends PersistentObject 
  {
  
      public $id;
      public $device;
      public $serverId;
      public $volumeId;
  
      public static $json_name = 'volumeAttachment';
      public static $url_resource = 'os-volume_attachments';
  
      private $createKeys = array('volumeId', 'device');
  
      /**
       * updates are not permitted
       *
       * @throws OpenCloud\UpdateError always
       */
      public function update($params = array()) 
      {
          throw new Exceptions\UpdateError(Lang::translate('Updates are not permitted'));
      }
  
      /**
       * returns a readable name for the attachment
       *
       * Since there is no 'name' attribute, we'll hardcode something
       *
       * @api
       * @return string
       */
      public function name() 
      {
          return sprintf('Attachment [%s]', $this->volumeId ?: 'N/A');
      }
  
      /**
       * returns the JSON object for Create()
       *
       * @return stdClass
       */
      protected function createJson() 
      {
          $object = new \stdClass;
          
          foreach($this->createKeys as $key) {
              if (isset($this->$key)) {
                  $object->$key = $this->$key;
              }
          }
  
          return (object) array(
              $this->jsonName() => $object
          );
      }
  
  }