slapos_subscription_request: generate a discount on the first invoice

If the open order does not start the same day, do not ask user to pay for those missing days

master/bt5/slapos_subscription_request/SkinTemplateItem/portal_skins/slapos_subscription_request/SubscriptionRequest_createOpenSaleOrder.py

@@ -114,5 +114,33 @@ open_sale_order.OpenSaleOrder_updatePeriod()
 open_sale_order.plan()
 open_sale_order.validate()
 
+#######################################################
+# Discount
+unused_day_count = current_date - start_date
+if 0 < unused_day_count:
+  # If the open order starts before today,
+  # generate a discount to the user on his next invoice
+
+  sale_packing_list = portal.sale_packing_list_module.newContent(
+    portal_type="Sale Packing List",
+    title="first invoice discount for %s" % open_sale_order.getReference(),
+    # It should match the first open order invoice
+    stop_date=next_period_date,
+    **open_order_edit_kw
+  )
+  discount_service = portal.restrictedTraverse('service_module/slapos_discount')
+  sale_packing_list.newContent(
+    portal_type="Sale Packing List Line",
+    resource_value=discount_service,
+    quantity=unused_day_count / (next_period_date - start_date),
+    price=-subscription_request.getPrice(),
+    quantity_unit_value=discount_service.getQuantityUnitValue(),
+    base_contribution_list=discount_service.getBaseContributionList(),
+    use=discount_service.getUse(),
+    activate_kw=activate_kw
+  )
+  sale_packing_list.confirm()
+  sale_packing_list.stop()
+  sale_packing_list.deliver()
 
 return open_sale_order