<?php
// $Id: prepopulate.module,v 1.10 2008-05-03 18:04:54 add1sun Exp $

/**
 * @file
 * Fill form elements with data from GET values.
 *
 * Originally written by ea. Farris <eafarris@gmail.com>
 * Based on an idea from chx, from the conversation at
 * http://www.drupal.org/node/27155.
 */

/**
 * Implementation of hook_help().
 */
function prepopulate_help($path, $arg) {
  switch ($path) {
    case 'admin/modules#description':
      return t('Prepopulates forms for allowed content types with HTTP GET data');
      break;
  }
}

/**
 * Implementation of hook_form_alter().
 */
function prepopulate_form_alter(&$form, $form_state, $form_id) {
  switch ($form_id) {
    // Add our checkbox to the content type edit forms
    // (admin/content/node-type/$type).
    case 'node_type_form':
      $type = $form['#node_type']->type;
      $form['workflow']['prepopulate_allowed'] = array(
        '#type' => 'checkbox',
        '#title' => 'Prepopulate form from URL?',
        '#default_value' => variable_get('prepopulate_allowed_'. $type, TRUE),
        '#description' => t('Allows fields to be prepopulated from the URL'),
      );
    return;
  }

  // Process the URL on a node add/edit form (node/add/$type).
  if (isset($form['#node'])) {
    $node = $form['#node'];
    // Make sure this node type allows prepopulate and
    // that we have a $_GET variable in the URL.
    if (variable_get('prepopulate_allowed_'. $node->type, TRUE) && isset($_GET['edit'])) {
      foreach (array_keys((array)$_GET['edit']) as $getvar) {
        if (element_child($getvar) && !is_null($form[$getvar])) {
          _prepopulate_get_walk($form[$getvar], $_GET['edit'][$getvar]);
        }
      }
    }
  }
}

/**
 * Internal helper to set element values from the $_GET variable.
 *
 * @param &$form
 *   Array. A form element.
 * @param &$getslice
 *   String or array. Value(s) to be applied to the element.
 */
function _prepopulate_get_walk(&$form, &$getslice) {
  if (!is_array($getslice)) {
    $form['#default_value'] = $getslice;
  }
  else {
    foreach (array_keys($getslice) as $getvar) {
      if (element_child($getvar) && is_array($form) && !is_null($form[$getvar])) {
        _prepopulate_get_walk($form[$getvar], $getslice[$getvar]);
      }
    }
  }
}