Hi,

What we’ll be trying to accomplish: Show a PreOrder button instead of the default Order button
on Magento 1.4.1.1 whenever:

1. The product’s stock quantity is zero.
2. Backordering is enabled and the “Allow Qty Below 0 and Notify Customerâ€‌ option is selected.
3. The Stock Availability is set to “In Stockâ€‌

Step A: the addtocart.phtml

We’ll start with the addtocart.phtml template located in
/app/design/frontend/default/default/catalog/product/view/addtocart.phtml,
where the defaults are your interface and template names respectively.

We’ll basically replace the default button markup with the following code:

		<?php define(CUSTOM_BACKORDERS_YES_NOTIFY , 2) ;
			  define(CUSTOM_STOCK_INSTOCK, 1);
			  $rquantity = (int)Mage::getModel('cataloginventory/stock_item')->loadByProduct($_product)->getQty();  
			  $rbackorder = $_product->getStockItem()->getBackorders(); 
			  $rstockavailability = $_product->getStockItem()->getIsInStock();  ?>
		<?php if (($rquantity == 0) && ($rbackorder == CUSTOM_BACKORDERS_YES_NOTIFY) && ($rstockavailability == CUSTOM_STOCK_INSTOCK) ) { ?>
		     <button type="button" title="<?php echo $this->__('Preorder') ?>" class="button btn-cart" onclick="productAddToCartForm.submit()"><span><span><?php echo $this->__('Preorder') ?></span></span></button>
		<?php } else { ?>
		     <button type="button" title="<?php echo $this->__('Add to Cart') ?>" class="button btn-cart" onclick="productAddToCartForm.submit()"><span><span><?php echo $this->__('Add to Cart') ?></span></span></button>
		<?php } ?>

Note that we are retrieving the Preorder string using Magento localiztion feature, we need to add this line
“Preorder”,”Preorder”
to
/app/design/frontend/default/default/locale/en_US/translate.csv

I actually tried to add a new file Mage_Catalog.csv in the above location which would make more sense but Magento didn’t pick it up.

Step B: the list.phtml

We’ll use the same code in list.phtml in two different places, the list mode listing and grid mode listing

<?php define(CUSTOM_BACKORDERS_YES_NOTIFY , 2) ;
			  define(CUSTOM_STOCK_INSTOCK, 1);
			  $rquantity = (int)Mage::getModel('cataloginventory/stock_item')->loadByProduct($_product)->getQty();  
			  $rbackorder = Mage::getModel('catalog/product')->load($_product->getId())->getStockItem()->getBackorders();
			  $rstockavailability = $_product->getStockItem()->getIsInStock(); ?>
			  <?php if (($rquantity == 0) && ($rbackorder == CUSTOM_BACKORDERS_YES_NOTIFY) && ($rstockavailability == CUSTOM_STOCK_INSTOCK) ) { ?>
					<button type="button" title="<?php echo $this->__('Preorder') ?>" class="button btn-cart" onclick="setLocation('<?php echo $this->getAddToCartUrl($_product) ?>')"><span><span><?php echo $this->__('Preorder') ?></span></span></button>
			  <?php } else { ?>
					<button type="button" title="<?php echo $this->__('Add to Cart') ?>" class="button btn-cart" onclick="setLocation('<?php echo $this->getAddToCartUrl($_product) ?>')"><span><span><?php echo $this->__('Add to Cart') ?></span></span></button>
<?php } ?>

As you can see the only change is using

<?php $rbackorder = Mage::getModel('catalog/product')->load($_product->getId())->getStockItem()->getBackorders(); ?>

instead of

<?php $rbackorder = $_product->getStockItem()->getBackorders(); ?>

This is probably because Magento didn’t load the full product model on the list view (the only difference I could think of is
the getProduct() ?> line inthe addtocart.phtml).

That’s about it, any suggestions or better best practices are greatly appreciated.