DEV: Use Discourse Events instead of topic model

config/locales/server.en.yml

@@ -56,7 +56,7 @@ en:
       subscription: "%{type} %{property} usage is not supported on your subscription"
       not_permitted_for_guests: "%{object_id} is not permitted when guests can access the wizard"
     error_messages:
-      wizard_replacing_composer: "A wizard is set to replace the composer in this category. You cannot create a topic here."
+      wizard_replacing_composer: "Category not allowed for topic creation."
 
   site_settings:
     custom_wizard_enabled: "Enable custom wizards."

lib/custom_wizard/extensions/topic_extension.rb

@@ -1,23 +1,8 @@
-# frozen_string_literal: true
-
-module CustomWizardTopicExtension
-  extend ActiveSupport::Concern
-
-  included { before_validation :check_wizard_replacement, on: :create }
-
-  def check_wizard_replacement
-    if wizard_replacing_composer?(self.category_id)
-      self.errors.add(
-        :base,
-        I18n.t('wizard.error_messages.wizard_replacing_composer')
-      )
-    end
-  end
-
-  def wizard_replacing_composer?(category_id)
-    return false unless category_id
-
-    category = Category.find(category_id)
-    category.custom_fields['create_topic_wizard'].present?
+DiscourseEvent.on(:before_create_topic) do |topic_params, user|
+  category = topic_params.category
+  if category&.custom_fields&.[]('create_topic_wizard').present?
+    raise Discourse::InvalidParameters.new(
+            I18n.t('wizard.error_messages.wizard_replacing_composer')
+          )
   end
 end

plugin.rb

@@ -202,7 +202,6 @@ after_initialize do
   ::InvitesController.prepend InvitesControllerCustomWizard
   ::UsersController.prepend CustomWizardUsersController
   ::Guardian.prepend CustomWizardGuardian
-  ::Topic.include CustomWizardTopicExtension
   
   full_path = "#{Rails.root}/plugins/discourse-custom-wizard/assets/stylesheets/wizard/wizard_custom.scss"
   if Stylesheet::Importer.respond_to?(:plugin_assets)

spec/extensions/topic_extension_spec.rb

@@ -1,37 +1,45 @@
 # frozen_string_literal: true
 
-class DummyTopic < Topic
-  include CustomWizardTopicExtension
-end
-
-describe DummyTopic, type: :model do
+describe Topic, type: :model do
   fab!(:category_with_wizard) do
     Fabricate(:category, custom_fields: { create_topic_wizard: 'true' })
   end
   fab!(:category_without_wizard) { Fabricate(:category) }
   fab!(:user) { Fabricate(:user) }
+  let(:valid_attrs) { Fabricate.attributes_for(:topic) }
 
-  context 'when the category has a create_topic_wizard custom field' do
-    it 'does not allow creating a topic directly' do
-      topic = DummyTopic.new(user: user, category: category_with_wizard)
-      topic.valid?
-      expect(topic.errors[:base]).to include(
-        I18n.t('wizard.error_messages.wizard_replacing_composer')
+  context 'with a create_topic_wizard custom field in the category' do
+    it 'will not allow creating a topic directly' do
+      expect do
+        TopicCreator.create(
+          user,
+          Guardian.new(user),
+          valid_attrs.merge(
+            title: 'A valid and sufficiently long title for testing',
+            category: category_with_wizard.id,
+            raw: 'hello this is a test topic with category with custom fields'
+          )
+        )
+      end.to raise_error(
+        Discourse::InvalidParameters,
+        'Category not allowed for topic creation.'
       )
     end
   end
 
-  context 'when the category does not have a create_topic_wizard custom field' do
-    it 'allows creating a topic directly' do
-      topic =
-        DummyTopic.new(
-          user: user,
-          category: category_without_wizard,
-          title: 'A valid topic title'
+  context 'without a create_topic_wizard custom field in the category' do
+    it 'will allow creating a topic directly' do
+      expect do
+        TopicCreator.create(
+          user,
+          Guardian.new(user),
+          valid_attrs.merge(
+            category: category_without_wizard.id,
+            title: 'Another valid and sufficiently long title for testing',
+            raw: 'This is the body of a valid topic'
+          )
         )
-      is_valid = topic.valid?
-      puts topic.errors.full_messages unless is_valid
-      expect(is_valid).to be_truthy
+      end.not_to raise_error
     end
   end
 end