feat(MED-97): update cart flow for using benefits

packages/features/medusa-storefront/src/lib/data/cart.ts

@@ -253,6 +253,37 @@ export async function setShippingMethod({
     .catch(medusaError);
 }
 
+export async function initiateMultiPaymentSession(
+  cart: HttpTypes.StoreCart,
+  benefitsAmount: number,
+) {
+  const headers = {
+    ...(await getAuthHeaders()),
+  };
+
+  return sdk.client.fetch<unknown>(`/store/multi-payment`, {
+    method: 'POST',
+    body: { cartId: cart.id, benefitsAmount },
+    headers,
+  })
+    .then(async (response) => {
+      console.info('Payment session initiated:', response);
+      const cartCacheTag = await getCacheTag('carts');
+      revalidateTag(cartCacheTag);
+      return response as {
+        montonioPaymentSessionId: string | null;
+        companyBenefitsPaymentSessionId: string | null;
+        totalByBenefits: number;
+        totalByMontonio: number;
+        isFullyPaidByBenefits: boolean;
+      };
+    })
+    .catch((e) => {
+      console.error('Error initiating payment session:', e, JSON.stringify(Object.keys(e)));
+      return medusaError(e);
+    });
+}
+
 export async function initiatePaymentSession(
   cart: HttpTypes.StoreCart,
   data: HttpTypes.StoreInitializePaymentSession,