Add Category Names to CatalogSearch

Helper_Search.php

<?php
class Custom_MyModule_Helper_Search
extends Mage_CatalogSearch_Helper_Data
{
    public function getSearchableDataFromCategory($productId, $storeId)
    {
        $result = array();
        
        $default = Mage::app()->getStore($storeId)->getRootCategoryId();
        $adapter = Mage::getSingleton('core/resource')->getConnection('core_read');
        $select = $adapter->select()
            ->from('catalog_category_product')
            ->where('product_id = ?', $productId)
            ;
        $query = $adapter->query($select);
        $categoryIds = array();
        while ($row = $query->fetch())
        {
            $categoryIds[] = $row['category_id'];
        }
        if(count($categoryIds) > 0)
        {
            $categories = Mage::getModel('catalog/category')->getCollection()
                ->addAttributeToSelect(array('path','name'))
                ->addAttributeToFilter('path', array('like' => '%/'.$default.'/%'))
                ->addAttributeToFilter('entity_id', array('in' => $categoryIds));
            foreach($categories as $_cat)
            {
                $result[] = $_cat->getName();
                $this->_cache[$_cat->getId()] = $_cat->getName();
                $path = $_cat->getPathIds();
                array_shift($path); // remove id "1"
                array_shift($path); // remove default store
                array_shift($path); // remove main category
                array_pop($path);   // remove current category
                foreach($path as $_id)
                {
                    if(!isset($this->_cache[$_id]))
                    {
                        $name = Mage::getModel('catalog/category')->getCollection()
                            ->addAttributeToSelect(array('name'))
                            ->addAttributeToFilter('entity_id', $_id)
                            ->getFirstItem()
                            ->getName();
                        $this->_cache[$_id] = $name;
                    }
                    $result[] = $this->_cache[$_id];
                }
            }
        }
        return array_unique($result);
    }
}

Simple.php

<?php

/*
also for the other Types, like "Configurable"
*/

class Custom_MyModule_Model_Catalog_Product_Type_Simple
extends Mage_Catalog_Model_Product_Type_Simple
{
    /**
     * Retrieve additional searchable data from type instance
     * Using based on product id and store_id data
     *
     * @param Mage_Catalog_Model_Product $product
     * @return array
     */
    public function getSearchableData($product = null)
    {
        $product    = $this->getProduct($product);
        $searchData = parent::getSearchableData($product);
        $categories = Mage::helper('mymodule/search')->getSearchableDataFromCategory($product->getId(), $product->getStoreId());
        return array_merge($searchData, $categories);
    }
}