Fix multi product/discount handling

insalan/payment/views.py

@@ -424,15 +424,15 @@ def create(self, request):
                     {"err": _("Préconditions de paiement non remplies")},
                     status=status.HTTP_400_BAD_REQUEST,
                 )
-            
+
             amount = transaction_obj.amount
-            
+
             # If the user has a discount for some products, apply them
             for product in transaction_obj.products.all():
                 discounts = Discount.objects.filter(user=payer, product=product, used=False)
-                if discounts.exists():
-                    discount = discounts.first()
-                    amount = transaction_obj.amount - discount.discount
+                for discount in discounts:
+                    amount -= discount.discount
+
                     # Add the discount to the transaction object
                     transaction_obj.discounts.add(discount)