/**
 * Implementation of hook_form().
 */
function panels_node_form(&$node, &$param) {
  $form['panels_node']['#tree'] = TRUE;
  if (empty($node->nid)) {
    // Grab our selected layout from the $node, If it doesn't exist, try arg(3)
    // and if that doesn't work present them with a list to pick from.
    $panel_layout = isset($node->panel_layout) ? $node->panel_layout : arg(3);
    if (!isset($node->panel_layout) && arg(3)) {
      $node->panel_layout = arg(3);
    }
    if (empty($panel_layout)) {
      $opts = $_GET;
      unset($opts['q']);
      return drupal_goto('node/add/panel/choose-layout', $opts);
    }


    panels_load_include('plugins');
    $layout = panels_get_layout($panel_layout);
    if (empty($layout)) {
      return drupal_not_found();
    }
    $form['panels_node']['layout'] = array(
      '#type' => 'value',
      '#value' => $panel_layout,
    );
  }