From de68e746c815a537d42edab1f3eab080b0d7dd8c Mon Sep 17 00:00:00 2001
From: Blessy Louis <112788477+BlessyLouis@users.noreply.github.com>
Date: Tue, 30 Jun 2026 14:13:36 +0530
Subject: [PATCH] Enhance processCart to include cart discount logic

Refactor processCart to calculate cart subtotal and apply cart-level discounts based on rules.
---
 src/engine/discountEngine.js | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/engine/discountEngine.js b/src/engine/discountEngine.js
index 190f2a7..316ced9 100644
--- a/src/engine/discountEngine.js
+++ b/src/engine/discountEngine.js
@@ -163,7 +163,38 @@ export function applyDiscounts(item, rules) {
  * Returns an array of DiscountResult objects.
  */
 export function processCart(cartItems, rules) {
-  return cartItems.map((item) => applyDiscounts(item, rules))
+  const itemResults = cartItems.map((item) =>
+    applyDiscounts(item, rules)
+  )
+
+  const subtotal = cartTotal(itemResults)
+
+  const cartRule = rules.find(
+    (r) =>
+      r.scope === 'cart' &&
+      subtotal >= Number(r.minCartValue)
+  )
+
+  if (!cartRule) {
+    return {
+      items: itemResults,
+      subtotal,
+      cartDiscount: 0,
+      finalTotal: subtotal,
+      cartRule: null
+    }
+  }
+
+  const cartDiscount =
+    Math.round(subtotal * cartRule.value / 100)
+
+  return {
+    items: itemResults,
+    subtotal,
+    cartDiscount,
+    finalTotal: subtotal - cartDiscount,
+    cartRule
+  }
 }
 
 /**