<?php
/**
 * Query By Form
 *
 * This module allows node modules to add a query by form tab for their node
 * types to the default search form
 *
 * @copyright 2008 Ouest Systemes Informatiques (OSInet)
 * @author Frederic G. MARAND
 * @version $Id: qbf.module,v 1.2 2008-08-25 15:03:33 marand Exp $
 * @license CeCILL 2.0
 * @package QBF
 */

define('QBF_LEVEL_REMOVE',           0);
define('QBF_LEVEL_OPTIONAL',         1);
define('QBF_LEVEL_REQUIRED',         2);

function _qbf_view($usNodeType = NULL)
  {
  $nodeType = filter_xss($usNodeType, array());

  $arNodeTypes = node_get_types();
  //dsm($arNodeTypes);
  $arFuncs1 = get_defined_functions();
  $arFuncs1 = $arFuncs1['user'];
  $node = new stdClass();
  $node->type = 'poll';
  $arFuncs1 = node_forms();
  //dsm($arFuncs1);
  $form = node_form($node, array('qbe-key' => 'qbe-value'));
  //dsm($form);
  return 'foo';
  }

function qbf_rewrite_form($form)
  {
  $hookName = 'qbf_rewrite_form';

  foreach (module_implements($hookName) as $module)
    {
    $function = "${module}_$hookName";
    $form = $function($form);
    }
  return drupal_get_form($form);
  }

/**
 * Transform a form array for QBF
 *
 * This function obtains the form array using Forms API, and transforms it by
 * modifying widgets to other types where needed.
 *
 * The $arHooks array contains hooks to be invoked, indexed by hook name, with
 * their arguments
 *
 * @param string $form_id
 * @param array $arHooks
 * @return array
 */
function qbf_transform_form($form_id, $arHooks = array())
  {
  // Fetch the basic form and rename it
  $form = drupal_retrieve_form($form_id, NULL);
  $newFormId = "qbf_$form_id";

  // Invoke the optional hooks extending it
  foreach ($arHooks as $hookName => $arHookArguments)
    {
    // dsm("Firing $hookName");

    foreach (module_implements($hookName) as $module)
      {
      $function = $module .'_'. $hookName;
      switch ($hookName)
        {
        case 'form':
          // @todo FIXME needs node with type property set
          // $formAdditions = node_invoke(new stdClass(), $hookName, $arHookArguments);
          break;
        default:
          $formAdditions = module_invoke_all($hookName, $arHookArguments);
          break;
        }
      // dsm(array($function => $formAdditions));
      }

  	if (is_array($formAdditions))
  	  {
  	  $form = array_merge_recursive($form, $formAdditions);
  	  }
    }

  // Only keep the children of the form
  $elements = array();
  $newForm = array();
  $form['mark'] = array('#type' => 'textarea', '#value' => 'goo');
  foreach (element_children($form) as $key)
    {
    // dsm("Transforming $key, type " . $form[$key]['#type']);
    $newElement = _qbf_transform_element($key, $form[$key]);
    if (!is_null($newElement))
      {
      $newForm[$key] = $newElement;
      }
    }

  $newForm['#id'] = $newFormId;
// dsm($newForm);
  return $newForm;
  }

/**
 * Transform a form element for QBF
 *
 * QBF-specific properties are:
 * - #qbf : array of properties
 * - #level: only within #qbf @see QBF_* constants
 *
 * @param array &$element
 * @return void
 */
function _qbf_transform_element($key, array $element)
  {
  // dsm(array('key' => $key, 'element' => $element));

  // Types without a default transformation are not transformed
  static $arDefaultTypeTransformations = array
    (
    'button'         => NULL,
    'file'           => NULL,
    'hidden'         => NULL,
    'markup'         => NULL,
    'password'       => NULL,
    'radio'          => NULL,
    'submit'         => NULL,
    'textarea'       => 'textfield',
    'value'          => NULL,
    );

  // Properties without a default transformation are not transformed
  static $arDefaultPropertyTransformations = array
    (
    // Standard properties
    '#action'        => NULL,
    '#after_build'   => NULL,
    '#base'          => NULL,
    '#button_type'   => NULL,
    '#built'         => NULL,
    '#description'   => NULL,
    '#method'        => NULL,
    '#parents'       => NULL,
    '#redirect'      => NULL,
    '#ref'           => NULL,
    '#required'      => NULL,
    '#rows'          => NULL,
    '#submit'        => NULL,
    '#tree'          => NULL,
    '#validate'      => NULL,
    '#value'         => NULL,
    );

  // Property values causing element removal
  static $arKillerProperties = array
    (
    '#disabled'      => TRUE,
    );

  // Transform type
  $sourceType = $element['#type'];
  $destType = array_key_exists($sourceType, $arDefaultTypeTransformations)
    ? $arDefaultTypeTransformations[$sourceType]
    : $sourceType;

  if (is_null($destType))
    {
    $ret = NULL;
    }
  else
    {
    $ret = $element;
    $ret['#type'] = $destType;
    if (!array_key_exists('#qbf', $element) || $element['#qbf']['#level'] == QBF_LEVEL_REMOVE)
      {
      $ret = NULL;
      }
    else
      {
      foreach (element_properties($element) as $propertyName)
        {
        // Apply killer properties first to avoid useless work
        if (array_key_exists($propertyName, $arKillerProperties) && ($element[$propertyName] = $arKillerProperties[$propertyName]))
          {
          $ret = NULL;
          break;
          }

        // Now transform or copy remaining properties
        if (array_key_exists($propertyName, $arDefaultPropertyTransformations))
          {
          $ret[$propertyName] = $arDefaultPropertyTransformations[$propertyName];
          }
        else
          {
          $ret[$propertyName] = $element[$propertyName];
          }

        // And apply form-defined overrides
        if ($propertyName == '#qbf')
          {
          foreach ($element[$propertyName] as $overrideName => $overrideValue)
            {
          	$ret[$overrideName] = $overrideValue;
            }
          }
        }

      foreach (element_children($element) as $childName)
        {
        $child = _qbf_transform_element($childName, $element[$childName]);
        if (is_null($child))
          {
          unset($ret[$childName]);
          }
        else
          {
          $ret[$childName] = $child;
          }
        }
      }
    }

  //dsm(array('key' => $key, 'transformed element' => $ret));
  return $ret;
  }