feat(billing): add calculate_total_new_price utility for dynamic payment calculation ✨

billing/views.py

@@ -15,6 +15,7 @@ from api.tasks import add_new_devices_to_omada
 from apibase.env import BASE_DIR, env
 from django.db.models import Prefetch
 import logging
+from .utils import calculate_total_new_price
 
 from .models import Device, Payment, Topup, WalletTransaction
 from .serializers import (
@@ -103,8 +104,9 @@ class ListCreatePaymentView(StaffEditorPermissionMixin, generics.ListCreateAPIVi
                 {"message": "device_ids are required."},
                 status=status.HTTP_400_BAD_REQUEST,
             )
-        # Create payment
-        amount = 100
+        amount = calculate_total_new_price(
+            number_of_devices=number_of_devices, number_of_months=number_of_months
+        )
         payment = Payment.objects.create(
             amount=amount,
             number_of_months=number_of_months,