Show default code if admin attribute field is blank

Question

I have old code that displays a pdf from the media folder. It shows if there is a file named for it. But now for the customer to enter a NEW pdf I created an attribute called pdf_download where they can paste in the file path in the admin and it appears on the page. Currently both pdfs show when a new one is entered. I wrote a small snippet at the bottom creating $specsheet. Ultimately I would like for the script to hide the old code if the admin field is populated. When I impliment the small part at the bottom it kills my attribute from rendering. What am I missing?

<?php 
        $_helper = Mage::helper('productattachments');
        $attachments = $_helper->getAttachmentsForProduct($this->getParentBlock()->getProduct()->getId());
    ?>


    <?php if (!empty($attachments)): ?>
    <div class="ac-attachments">
        <?php  $header_attachment = Mage::getStoreConfig('attachments_module_configuration/settings_group/show_attachment_label'); ?>
        <?php if ($header_attachment != ''): ?>    
            <h2><?php echo $header_attachment; ?></h2>
        <?php endif; ?>
        <ul>
            <?php foreach($attachments as $attachment): ?>
                <li>                
                    <?php if ($_helper->isIconEnabled($attachment->getFilename()) && $_helper->getFileTypeIcon($attachment->getFilename()) !== NULL): ?>
                        <img src="<?php echo $_helper->getFileTypeIcon($attachment->getFilename()); ?>" />                
                    <?php endif; ?>
                    <a href="<?php echo Mage::getUrl('productattachments/index/downloadfile', array('name' => $attachment->getFilename(), 'att_id' => $attachment->getProductattachments_id())); ?>">
                        <?php echo $attachment->getTitle(); ?>

                        <?php if ($_helper->isShowSizeEnabled()): ?>
                            <?php $file_size = $_helper->getFileSize($attachment->getFilename()); ?>
                            <?php if ($file_size != ''): ?>
                                (<?php echo $file_size; ?>)
                            <?php endif;   ?>                        
                        <?php endif; ?>
                    </a>
                </li>
            <?php endforeach; ?>
        </ul>    
    </div>
    <?php endif; ?>


    <?php $specsheet = trim($_product->getPdfDownload());
      if (empty($specsheet)) {
        echo $attachment 
    }
    ?>

Answer 1

Try

<?php 
    $_product = $this->getParentBlock()->getProduct();
    $_helper = Mage::helper('productattachments');
    $attachments = $_helper->getAttachmentsForProduct($_product->getId());
?>

<?php $specsheet = trim($_product->getPdfDownload()); ?>

<?php if (!empty($specsheet)): ?>
   display attribute 
<?php elseif (!empty($attachments)): ?>
   display old code
<?php endif; ?>

Answer 2

please this

   <?php 
    if(Mage::registry('current_product')):
    $Product=Mage::registry('current_product')
    else:
   $Product= Mage::getModel('catalog/product')->load($this->getParentBlock()->getProduct());
   endif;
    $specsheet = trim($Product->getPdfDownload());
      if (empty($specsheet)) {
        echo $attachment 
    }
    ?>

registry will work if it is product page

Mage::registry('current_product'):

else load product by product id