Move shipping method id setting code to OrderWorkflow service

app/controllers/checkout_controller.rb

@@ -175,9 +175,7 @@ class CheckoutController < Spree::StoreController
         return if redirect_to_payment_gateway
       end
 
-      @order.select_shipping_method(shipping_method_id) if @order.state == "delivery"
-
-      next if OrderWorkflow.new(@order).next
+      next if OrderWorkflow.new(@order).next({ shipping_method_id: shipping_method_id })
 
       return update_failed
     end

app/services/order_workflow.rb

@@ -13,9 +13,13 @@ class OrderWorkflow
     advance_order!(advance_order_options)
   end
 
-  def next
+  def next(options = {})
     tries ||= 3
-    order.next
+    result = order.next
+
+    after_transition_hook(options)
+
+    result
   rescue ActiveRecord::StaleObjectError
     retry unless (tries -= 1).zero?
     false