Unwithdraw interactor

app/controllers/unwithdraw_controller.rb

@@ -12,13 +12,13 @@ def confirm
   end
 
   def unwithdraw
-    Edition.find_and_lock_current(document: params[:document]) do |edition|
-      UnwithdrawService.new.call(edition, current_user)
-      redirect_to edition.document
+    result = Unwithdraw::UnwithdrawInteractor.call(params: params, user: current_user)
+
+    if result.api_error
+      redirect_to document_path(params[:document]),
+        alert_with_description: t("documents.show.flashes.unwithdraw_error")
+    else
+      redirect_to document_path(params[:document])
     end
-  rescue GdsApi::BaseError => e
-    GovukError.notify(e)
-    redirect_to document_path(params[:document]),
-      alert_with_description: t("documents.show.flashes.unwithdraw_error")
   end
 end

app/interactors/unwithdraw/unwithdraw_interactor.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class Unwithdraw::UnwithdrawInteractor
+  include Interactor
+
+  delegate :params, :user, :edition, :api_error, to: :context
+
+  def call
+    Edition.transaction do
+      find_and_lock_edition
+      unwithdraw
+    end
+  end
+
+private
+
+  def find_and_lock_edition
+    context.edition = Edition.lock.find_current(document: params[:document])
+  end
+
+  def unwithdraw
+    UnwithdrawService.new.call(edition, user)
+  rescue GdsApi::BaseError => e
+    GovukError.notify(e)
+    context.fail!(api_error: true)
+  end
+end