Redirect Simple Products to Configurable Parents with Options Preselected in Magento 1

config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <DaanvandenBergh_RedirectSimpleProducts>
            <version>1.0.0</version>
        </DaanvandenBergh_RedirectSimpleProducts>
    </modules>
    <global>
        <models>
            <daanvandenbergh_redirectsimpleproducts>
                <class>DaanvandenBergh_RedirectSimpleProducts_Model</class>
            </daanvandenbergh_redirectsimpleproducts>
        </models>
    </global>
    <frontend>
        <events>
            <controller_action_predispatch_catalog_product_view>
                <observers>
                    <daanvandenbergh_redirectsimpleproducts>
                        <class>daanvandenbergh_redirectsimpleproducts/observer</class>
                        <method>redirectToConfigurable</method>
                    </daanvandenbergh_redirectsimpleproducts>
                </observers>
            </controller_action_predispatch_catalog_product_view>
        </events>
    </frontend>
</config>

DaanvandenBergh_RedirectSimpleProducts.xml

<?xml version="1.0"?>
<config>
    <modules>
        <DaanvandenBergh_RedirectSimpleProducts>
            <codePool>local</codePool>
            <active>true</active>
            <depends>
                <Mage_Catalog />
            </depends>
        </DaanvandenBergh_RedirectSimpleProducts>
    </modules>
</config>

Observer.php

<?php

class DaanvandenBergh_RedirectSimpleProducts_Model_Observer {

	public function redirectToConfigurable( $observer ) {
		$id                    = Mage::app()->getRequest()->getParam( 'id' );
		$configurableParentIds = Mage::getResourceSingleton( 'catalog/product_type_configurable' )->getParentIdsByChild( $id );

		if ( isset( $configurableParentIds[0] ) ) {
			$mainProduct = Mage::getModel( 'catalog/product' )
			                   ->setStoreId( Mage::app()->getStore()->getId() )
			                   ->load( $configurableParentIds[0] );

			$productAttributeOptions = $mainProduct->getTypeInstance( true )->getConfigurableAttributesAsArray( $mainProduct );

			$attributeOptions = array();
			foreach ( $productAttributeOptions as $productAttribute ) {
				$simpleProduct = Mage::getModel( 'catalog/product' )->getCollection()
				                     ->addAttributeToFilter( 'entity_id', array( 'eq' => $id ) )
				                     ->addAttributeToSelect( $productAttribute['attribute_code'] )
				                     ->setPageSize( 1 )
				                     ->getFirstItem();

				$attributeOptions[ $productAttribute['attribute_id'] ] = $simpleProduct->getData( $productAttribute['attribute_code'] );
			}
			Mage::getSingleton( 'core/session' )->setSuperAttributes( $attributeOptions );

			Mage::app()->getResponse()->setRedirect( $mainProduct->getProductUrl(), 301 );
			Mage::app()->getResponse()->sendResponse();
			exit;
		}

		return $this;
	}
}