How can I override the core sales order model class ?

[vitts]

I want edit  sendNewOrderEmail()  function from  Mage_Sales_Model_Order class . I want achieve following task as,

1. Need to set different template for new order email on the basis of product type.

EX . If product type is  downloadable need to send downloadbale template.

If product is simple need to send simple email template for logged in users.

How Do I achieve?

Any Help... Thanks in advance....

[OST Agency · Accepted solution]

To send different order confirmation email depending on specific criteria you would either have to :

1. Rewrite sendNewOrderEmail() in Mage_Sales_Model_Order and add logic to check the template
2. Disable magento "order confirmation email" in system config, then create a custom module to send your email by coping logic from sendNewOrderEmail() using event/observer
3. For simple text changes, you could use template logic {{if order.customer_group_id}} or {{depend order.customer_group_id}} but they seem to only evaluate true/false condition, therefore for more advance logic you could include a block

{{block type='core/template' area='frontend' template='sales/custom_logic.phtml' order=$order}}

In custom_logic.phtml

<?php $order = $this->getOrder() if($order->getCustomerGroupId() == 1){ ///do ....