Preview interactors

app/controllers/preview_controller.rb

@@ -2,22 +2,16 @@
 
 class PreviewController < ApplicationController
   def create
-    Edition.find_and_lock_current(document: params[:document]) do |edition|
-      begin
-        if Requirements::EditionChecker.new(edition).pre_preview_issues.any?
-          redirect_to document_path(edition.document), tried_to_preview: true
-          next
-        end
+    result = Preview::CreateInteractor.call(params: params, user: current_user)
+    issues, preview_failed = result.to_h.values_at(:issues, :preview_failed)
 
-        PreviewService.new(edition).create_preview
-      rescue GdsApi::BaseError => e
-        GovukError.notify(e)
-        redirect_to document_path(edition.document),
-                    alert_with_description: t("documents.show.flashes.preview_error")
-        next
-      end
-
-      redirect_to preview_document_path(edition.document)
+    if issues
+      redirect_to document_path(params[:document]), tried_to_preview: true
+    elsif preview_failed
+      redirect_to document_path(params[:document]),
+                  alert_with_description: t("documents.show.flashes.preview_error")
+    else
+      redirect_to preview_document_path(params[:document])
     end
   end
 

app/interactors/preview/create_interactor.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class Preview::CreateInteractor
+  include Interactor
+
+  delegate :params,
+           :user,
+           :edition,
+           :issues,
+           :preview_failed,
+           to: :context
+
+  def call
+    Edition.transaction do
+      find_and_lock_edition
+      check_for_issues
+      create_preview
+    end
+  end
+
+private
+
+  def find_and_lock_edition
+    context.edition = Edition.lock.find_current(document: params[:document])
+  end
+
+  def check_for_issues
+    issues = Requirements::EditionChecker.new(edition).pre_preview_issues
+    context.fail!(issues: issues) if issues.any?
+  end
+
+  def create_preview
+    PreviewService.new(edition).create_preview
+  rescue GdsApi::BaseError => e
+    GovukError.notify(e)
+    context.fail!(preview_failed: true)
+  end
+end