fix(types,utils,promotion): Move from total to original_total to resolve edge case for adjustments calculation (#13106)

* Move from total to original_total to resolve edge case in adjustment calculation

* Added changeset

* Added test case for correction

---------

Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/core/types/src/promotion/common/compute-actions.ts

@@ -188,7 +188,7 @@ export interface ComputeActionItemLine extends Record<string, unknown> {
   /**
    * The total of the line item.
    */
-  total: BigNumberInput
+  original_total: BigNumberInput
 
   /**
    * Whether the line item is discountable.
@@ -218,7 +218,7 @@ export interface ComputeActionShippingLine extends Record<string, unknown> {
   /**
    * The total of the shipping method.
    */
-  total: BigNumberInput
+  original_total: BigNumberInput
 
   /**
    * The adjustments applied before on the shipping method.

packages/core/utils/src/totals/promotion/index.ts

@@ -53,8 +53,8 @@ function getLineItemSubtotal(lineItem) {
   return MathBN.div(lineItem.subtotal, lineItem.quantity)
 }
 
-function getLineItemTotal(lineItem) {
-  return MathBN.div(lineItem.total, lineItem.quantity)
+function getLineItemOriginalTotal(lineItem) {
+  return MathBN.div(lineItem.original_total, lineItem.quantity)
 }
 
 export function calculateAdjustmentAmountFromPromotion(
@@ -95,7 +95,7 @@ export function calculateAdjustmentAmountFromPromotion(
 
     const lineItemAmount = MathBN.mult(
       promotion.is_tax_inclusive
-        ? getLineItemTotal(lineItem)
+        ? getLineItemOriginalTotal(lineItem)
         : getLineItemSubtotal(lineItem),
       quantity
     )
@@ -134,11 +134,11 @@ export function calculateAdjustmentAmountFromPromotion(
   */
 
   const remainingItemAmount = MathBN.sub(
-    promotion.is_tax_inclusive ? lineItem.total : lineItem.subtotal,
+    promotion.is_tax_inclusive ? lineItem.original_total : lineItem.subtotal,
     promotion.applied_value
   )
   const itemAmount = MathBN.div(
-    promotion.is_tax_inclusive ? lineItem.total : lineItem.subtotal,
+    promotion.is_tax_inclusive ? lineItem.original_total : lineItem.subtotal,
     lineItem.quantity
   )
   const maximumPromotionAmount = MathBN.mult(

packages/modules/promotion/src/utils/compute-actions/line-items.ts

@@ -110,7 +110,7 @@ function applyPromotionToItems(
         MathBN.sub(
           MathBN.add(
             acc,
-            promotion.is_tax_inclusive ? item.total : item.subtotal
+            promotion.is_tax_inclusive ? item.original_total : item.subtotal
           ),
           appliedPromotionsMap.get(item.id) ?? 0
         ),
@@ -124,7 +124,10 @@ function applyPromotionToItems(
 
   for (const item of applicableItems) {
     if (
-      MathBN.lte(promotion.is_tax_inclusive ? item.total : item.subtotal, 0)
+      MathBN.lte(
+        promotion.is_tax_inclusive ? item.original_total : item.subtotal,
+        0
+      )
     ) {
       continue
     }