change product price in order(After changing the quanity)

Question

I have created a module to edit the products. Everything is working fine except the percentage discount rule. When a customer changed the item quantity from 5 to 1, the discount amount was not changed in the order.

Guys could you help me in this.

Answer 1

You gotta resort to the Rewrite:

1. /app/code/local/YourCompany/YourModule/etc/config.xml

   <global>
       <models>
           <salesrule>
               <rewrite>                    
                   <quote_discount>YourCompany_YourModule_Model_SalesRule_Quote_Discount</quote_discount>
               </rewrite>
            </salesrule>
        </models>
   </global>
   

2. /app/code/local/YourCompany/YourModule/Model/SalesRule/Quote/Discount.php

   class YourCompany_YourModule_Model_SalesRule_Quote_Discount extends Mage_SalesRule_Model_Quote_Discount
   {
      /**
       * @param Mage_Sales_Model_Quote_Item_Abstract $item
       * @return Mage_SalesRule_Model_Quote_Discount
       */
      protected function _aggregateItemDiscount($item) {
          $this->transferOldItemDiscount($item); //transfer old discount
          return parent::_aggregateItemDiscount($item);
      }
   
      /**
       * @param $item
       * @return $this
       */
      protected function transferOldItemDiscount($item) {
          if (!Mage::helper('mageworx_ordersedit')->isEnabled()) {
              return $this;
          }
          $orderId = Mage::getSingleton('adminhtml/session_quote')->getOrderId();
          if (!$orderId) {
              return $this;
          }
   
          /** @var Mage_Sales_Model_Order $order */
          $order = Mage::getModel('sales/order')->load($orderId);
          if (!$order->getId()) {
              return $this;
          }
   
          $data = Mage::app()->getRequest()->getPost('order');
          if (isset($data['coupon']['code']) && empty($data['coupon']['code'])) {
              Mage::getSingleton('adminhtml/session_quote')->setCouponCodeIsDeleted(true);
          }
   
          /** @var Mage_Sales_Model_Quote $quote */
          $quote = $item->getQuote();
          // if new coupon or deleted - discount do not touch
          if (Mage::getSingleton('adminhtml/session_quote')->getCouponCodeIsDeleted() || ($quote->getCouponCode() && $quote->getCouponCode()!=$order->getCouponCode())) {
              return $this;
          }
   
          $quote->setAppliedRuleIds($order->getAppliedRuleIds());
   
          $orderItems = $order->getAllItems();
          /** @var Mage_Sales_Model_Order_Item $orderItem */
          foreach ($orderItems as $orderItem) {
              if ($orderItem->getProductId()==$item->getProductId()) {
                  if ($orderItem->getAppliedRuleIds() && $orderItem->getBaseDiscountAmount()>0) {
                      $baseDiscount = ($orderItem->getBaseDiscountAmount() / $orderItem->getQtyOrdered()) * $item->getQty();
                      $discount = ($orderItem->getDiscountAmount() / $orderItem->getQtyOrdered()) * $item->getQty();
                      $item->setBaseDiscountAmount($baseDiscount)->setDiscountAmount($discount)->setAppliedRuleIds($orderItem->getAppliedRuleIds());
                  } else {
                      $item->setBaseDiscountAmount(0)->setDiscountAmount(0)->setAppliedRuleIds(null);
                  }
                  return $this;
              }
          }
      }
   }