<?php
/**
* This module demonstrates a way to create Google Gadgets from within Drupal.
*
* It is expected that users will actually evolve it to a generalized gadget
* creation class, from which actual gadgets will be derived without having to
* create a module for each gadget.
*
* It requires PHP5 and the DOM extension.
*
* Licensed under the CeCILL 2.0.
* Also licenced under the General Public License 2.0 and later, for compatibility
* with Drupal itself.
*
* @copyright  2007-2009 Frederic G. MARAND fgm@riff.org
* @license    http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
*/

/*
 * Base class for gadget creation
 */
class GoogleGadget
  {
  /**
   * Content type attribute
   *
   * @var string
   */
  public $contentType;

  /**
   * Raw content. Data should be in the format described by $this->contentType
   * @var string
   */
  public $content = '';

  /**
   * Hold elements (#-prefixed) and attributes below ModulePrefs
   *
   * @var array
   */
  public $modulePrefs;

  /**
   * Hold attributes for UserPref elements
   *
   * @var array
   */
  public $userPrefs;

  /**
   * Constructor builds an empty HTML element by default
   *
   * @param mixed $body
   */
  public function __construct($body = '', $type = 'html')
    {
    $this->contentType = $type;
      $this->content = $body;
      $this->modulePrefs = array();
      $this->userPrefs = array();
    }

  /**
   * Shortcut to set up module preferences
   *
   * @param string $section
   * @param string $name
   * @param string $value
   * @return void
   */
  public function setModulePref($section, $name, $value)
    {
    $this->modulePrefs["#$section"][$name] = $value;
    }

  /**
   * Add user-defined preferences
   *
   * $attributes is an associative array of optional name/value attribute pairs
   *
   * @param string $name
   * @param string $displayName
   * @param array $attributes
   */
  public function addUserPref($name, $displayName, $attributes = array())
    {
    $this->userPrefs[$name] = $attributes;
    $this->userPrefs[$name]['name'] = $name;
    $this->userPrefs[$name]['display_name'] = $displayName;
    }

  /**
   * Return the rendered module and die() to avoid drupal theming on XML content
   *
   * @return void
   */
  public function render()
    {
    /**
     * We don't use drupal_set_header because we're not letting drupal do the
     * rendering
     */
    header('Content-type: text/xml; charset=utf-8');

    $doc = new DOMDocument();
    $module = $doc->createElement('Module');
    $module = $doc->appendChild($module);

    /**
     * module preferences
     */
    if (count($this->modulePrefs) > 0)
      {
      $prefsNode = $doc->createElement('ModulePrefs');
      $prefsNode = $module->appendChild($prefsNode);
      $sections = array();

      foreach ($this->modulePrefs as $prefName => $prefValue)
        {
        if ($prefName[0] == '#')
          {
          $prefName = substr($prefName, 1);
          if (!in_array($prefName, $sections)) // must create it
            {
              ${$prefName} = $doc->createElement($prefName);
              ${$prefName} = $prefsNode->appendChild(${$prefName});
              $sections[] = $prefName;
            }
          foreach ($prefValue as $attrName => $attrValue)
            {
              ${$prefName}->setAttribute($attrName, $attrValue);
            }
          }
        else
          {
          $prefsNode->setAttribute($prefName, $prefValue);
          }
        }
      } // module preferences

    /**
     * user preferences
     */
    if (count($this->userPrefs > 0))
      {
      foreach ($this->userPrefs as $prefArray)
        {
          $prefNode = $doc->createElement('UserPref');
          $prefNode = $module->appendChild($prefNode);
          foreach ($prefArray as $prefName => $prefValue)
            {
            $prefNode->setAttribute($prefName, $prefValue);
            }
        }
      }

    /**
     * module contents
     */
    $content = $doc->createElement('Content');
    $content = $module->appendChild($content);
    $content->setAttribute('type', $this->contentType);
    $data = $doc->createCDATASection($this->content);
    $data = $content->appendChild($data);

    /**
     * clean up
     */
      echo $doc->saveXML();
      die();
    }
  } // end of class

/**
 * Implement hook_menu
 *
 * @param boolean $may_cache
 * @return array
 */
function gadgets_menu()
  {
  $items = array();
  $items['gadgets/api'] = array(
    'title'            => 'Google Gadget sample',
    'description'      => 'Display a Drupal API search box',
    'access arguments' => array('access content'),
    'page callback'    => 'gadgets_main',
    );

  return $items;
  }

/**
 * Main entry point for gadget creation
 *
 * @return void
 */
function gadgets_main()
  {
  $g = new GoogleGadget(
<<<EOT
      <div style="padding: 0 0.5em; margin: 0">
        <script type="text/javascript">
      function drupalapisearch(q)
        {
        destination = "http://api.drupal.org/api/__UP_apiversion__/function/" + q;
          top.location.href = destination;
        }
          </script>
      <form name="drupalapiform" onsubmit="drupalapisearch(drupalapiform.q.value)">
        <input type="text" maxlength="128" name="q" size="40" value="" />
        <input type="submit" value="Lookup Drupal function" />
        </form>
      <script>_IG_AdjustIFrameHeight();</script>
      </div>
EOT
  );

  $g->contentType = 'html'; // default value, just added here to show it exists
  $g->modulePrefs['title'] = 'Drupal API reference';
  $g->modulePrefs['author'] = 'Frederic G. MARAND';
  $g->modulePrefs['description'] = 'A simple module to demonstrate how to build google gadgets within Drupal';
  $g->modulePrefs['author_email'] = 'http://blog.riff.org/contact';
  $g->modulePrefs['author_link'] = 'http://blog.riff.org/';
  $g->setModulePref('Require', 'feature', 'dynamic-height');
  $g->addUserPref('apiversion', 'Drupal API version', array
    (
    'default_value' => '6'
    ));
  $g->render(); // includes die() to avoid drupal themeing
  }