Tidy up FormsController

app/controllers/forms_controller.rb

@@ -25,41 +25,33 @@ def go_back
 
   private
 
+  def set_transient_registration(reg_identifier)
+    @transient_registration = TransientRegistration.where(reg_identifier: reg_identifier).first ||
+                              TransientRegistration.new(reg_identifier: reg_identifier)
+  end
+
   # Expects a form class name (eg BusinessTypeForm), a snake_case name for the form (eg business_type_form),
   # and the reg_identifier param
   def set_up_form(form_class, form, reg_identifier)
     set_transient_registration(reg_identifier)
 
-    unless @transient_registration.valid?
-      redirect_to page_path("errors/invalid")
-      return false
-    end
-
-    unless user_has_permission?
-      redirect_to page_path("errors/permission")
-      return false
-    end
-
-    unless form_matches_state?
-      redirect_to_correct_form
-      return false
-    end
+    return false unless transient_registration_is_valid? &&
+                        user_has_permission? &&
+                        state_is_correct?
 
     # Set an instance variable for the form (eg. @business_type_form) using the provided class (eg. BusinessTypeForm)
     instance_variable_set("@#{form}", form_class.new(@transient_registration))
   end
 
-  def user_has_permission?
-    can? :update, @transient_registration
-  end
-
-  def set_transient_registration(reg_identifier)
-    @transient_registration = TransientRegistration.where(reg_identifier: reg_identifier).first ||
-                              TransientRegistration.new(reg_identifier: reg_identifier)
-  end
-
-  def form_matches_state?
-    controller_name == "#{@transient_registration.workflow_state}s"
+  def submit_form(form, params)
+    respond_to do |format|
+      if form.submit(params)
+        @transient_registration.next!
+        format.html { redirect_to_correct_form }
+      else
+        format.html { render :new }
+      end
+    end
   end
 
   def redirect_to_correct_form
@@ -72,14 +64,27 @@ def form_path
     send("new_#{@transient_registration.workflow_state}_path".to_sym, @transient_registration.reg_identifier)
   end
 
-  def submit_form(form, params)
-    respond_to do |format|
-      if form.submit(params)
-        @transient_registration.next!
-        format.html { redirect_to_correct_form }
-      else
-        format.html { render :new }
-      end
-    end
+  # Guards
+
+  def transient_registration_is_valid?
+    return true if @transient_registration.valid?
+    redirect_to page_path("errors/invalid")
+    false
+  end
+
+  def user_has_permission?
+    return true if can? :update, @transient_registration
+    redirect_to page_path("errors/permission")
+    false
+  end
+
+  def state_is_correct?
+    return true if form_matches_state?
+    redirect_to_correct_form
+    false
+  end
+
+  def form_matches_state?
+    controller_name == "#{@transient_registration.workflow_state}s"
   end
 end