if ((Tools::getValue('id_product') || Tools::getValue('id_category')) && isset($this->context->cookie->last_visited_category) && $this->context->cookie->last_visited_category)
{
    $category = new Category($this->context->cookie->last_visited_category, $this->context->language->id);
    if (Validate::isLoadedObject($category))
        $this->smarty->assign(array('currentCategory' => $category, 'currentCategoryId' => $category->id));
}

$currentCategoryId = 0;
if(Tools::getValue('id_product'))
    $currentCategoryId = Db::getInstance()->getValue('SELECT product_shop.`id_category_default` FROM `'._DB_PREFIX_.'product` p '.Shop::addSqlAssociation('product', 'p').' WHERE p.`id_product` = '.(int)Tools::getValue('id_product'));
elseif(Tools::getValue('id_category'))
    $currentCategoryId = Tools::getValue('id_category');

$category = new Category($this->context->cookie->last_visited_category, $this->context->language->id);
if (Validate::isLoadedObject($category))
    $this->smarty->assign(array('currentCategory' => $category, 'currentCategoryId' => $currentCategoryId));

$cacheId = $this->getCacheId($category ? $category->id : null);

$cacheId = $this->getCacheId(Tools::getValue('id_category', 0) . '|' . Tools::getValue('id_product', 0) );