Add tags interactor

app/controllers/tags_controller.rb

@@ -11,18 +11,8 @@ def edit
   end
 
   def update
-    Edition.find_and_lock_current(document: params[:document]) do |edition|
-      updater = Versioning::RevisionUpdater.new(edition.revision, current_user)
-      updater.assign(tags: update_params(edition))
-
-      if updater.changed?
-        edition.assign_revision(updater.next_revision, current_user).save!
-        TimelineEntry.create_for_revision(entry_type: :updated_tags, edition: edition)
-        PreviewService.new(edition).try_create_preview
-      end
-
-      redirect_to edition.document
-    end
+    Tags::UpdateInteractor.call(params: params, user: current_user)
+    redirect_to document_path(params[:document])
   end
 
 private

app/interactors/tags/update_interactor.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+class Tags::UpdateInteractor
+  include Interactor
+
+  delegate :params,
+           :user,
+           :edition,
+           :unchanged,
+           to: :context
+
+  def call
+    Edition.transaction do
+      find_and_lock_edition
+      update_edition
+
+      create_timeline_entry
+      update_preview
+    end
+  end
+
+private
+
+  def find_and_lock_edition
+    context.edition = Edition.lock.find_current(document: params[:document])
+  end
+
+  def update_edition
+    updater = Versioning::RevisionUpdater.new(edition.revision, user)
+    updater.assign(tags: update_params(edition))
+
+    if updater.changed?
+      edition.assign_revision(updater.next_revision, user).save!
+    else
+      context.fail!(unchanged: true)
+    end
+  end
+
+  def create_timeline_entry
+    TimelineEntry.create_for_revision(entry_type: :updated_tags, edition: edition)
+  end
+
+  def update_preview
+    PreviewService.new(edition).try_create_preview
+  end
+
+  def update_params(edition)
+    permits = edition.document_type.tags.map do |tag_field|
+      [tag_field.id, []]
+    end
+
+    params.fetch(:tags, {}).permit(Hash[permits])
+  end
+end