Plugin for setup template by parent resource

autoTemplate.php

<?php
if ( $modx->event->name == 'OnDocFormRender' && $mode == modSystemEvent::MODE_NEW ) {
  $template = $modx->runSnippet( 'pdoField', array(
    "id" => $_REQUEST['parent']
  , "field" => "template"
  , "top" => 0
  ) );
  switch ( $template ) {
    case 1:
      $template = 2;
      break;
    default:
      $template = 1;
      break;
  }
  $modx->controller->setProperty( 'template', $template );
}