Move theme-related helper methods out of controller (#37807)

app/controllers/application_controller.rb

@@ -17,9 +17,6 @@ class ApplicationController < ActionController::Base
 
   helper_method :current_account
   helper_method :current_session
-  helper_method :current_theme
-  helper_method :color_scheme
-  helper_method :contrast
   helper_method :single_user_mode?
   helper_method :use_seamless_external_login?
   helper_method :sso_account_settings
@@ -173,20 +170,6 @@ class ApplicationController < ActionController::Base
     @current_session = SessionActivation.find_by(session_id: cookies.signed['_session_id']) if cookies.signed['_session_id'].present?
   end
 
-  def current_theme
-    return Setting.theme unless Themes.instance.names.include? current_user&.setting_theme
-
-    current_user.setting_theme
-  end
-
-  def color_scheme
-    current_user&.setting_color_scheme || 'auto'
-  end
-
-  def contrast
-    current_user&.setting_contrast || 'auto'
-  end
-
   def respond_with_error(code)
     respond_to do |format|
       format.any  { render "errors/#{code}", layout: 'error', status: code, formats: [:html] }

app/helpers/application_helper.rb

@@ -89,12 +89,6 @@ module ApplicationHelper
     Rails.env.production? ? site_title : "#{site_title} (Dev)"
   end
 
-  def page_color_scheme
-    return content_for(:force_color_scheme) if content_for(:force_color_scheme)
-
-    color_scheme
-  end
-
   def label_for_scope(scope)
     safe_join [
       tag.samp(scope, class: { 'scope-danger' => SessionActivation::DEFAULT_SCOPES.include?(scope.to_s) }),

app/helpers/theme_helper.rb

@@ -46,6 +46,24 @@ module ThemeHelper
     )
   end
 
+  def current_theme
+    return Setting.theme unless Themes.instance.names.include? current_user&.setting_theme
+
+    current_user.setting_theme
+  end
+
+  def color_scheme
+    current_user&.setting_color_scheme || 'auto'
+  end
+
+  def contrast
+    current_user&.setting_contrast || 'auto'
+  end
+
+  def page_color_scheme
+    content_for(:force_color_scheme).presence || color_scheme
+  end
+
   private
 
   def active_custom_stylesheet

spec/controllers/application_controller_spec.rb

@@ -85,20 +85,6 @@ RSpec.describe ApplicationController do
     end
   end
 
-  describe 'helper_method :current_theme' do
-    it 'returns "default" when theme wasn\'t changed in admin settings' do
-      allow(Setting).to receive(:default_settings).and_return({ 'theme' => 'default' })
-
-      expect(controller.view_context.current_theme).to eq 'default'
-    end
-
-    it 'returns instances\'s theme when user is not signed in' do
-      allow(Setting).to receive(:[]).with('theme').and_return 'contrast'
-
-      expect(controller.view_context.current_theme).to eq 'contrast'
-    end
-  end
-
   context 'with ActionController::RoutingError' do
     subject do
       routes.draw { get 'routing_error' => 'anonymous#routing_error' }

spec/helpers/theme_helper_spec.rb

@@ -100,6 +100,60 @@ RSpec.describe ThemeHelper do
     end
   end
 
+  describe '#current_theme' do
+    subject { helper.current_theme }
+
+    context 'when user is not signed in' do
+      context 'when theme was not changed in settings' do
+        it { is_expected.to eq('default') }
+      end
+
+      context 'when theme is changed in settings' do
+        before { Setting.theme = 'contrast' }
+
+        it { is_expected.to eq('contrast') }
+      end
+    end
+
+    context 'when user is signed in' do
+      before { allow(helper).to receive(:current_user).and_return(current_user) }
+
+      let(:current_user) { Fabricate :user }
+
+      context 'when user did not set theme' do
+        it { is_expected.to eq('default') }
+      end
+
+      context 'when user set theme' do
+        before { current_user.settings.update(theme: 'alternate', noindex: false) }
+
+        context 'when theme is valid' do
+          before { allow(Themes.instance).to receive(:names).and_return %w(default alternate good evil) }
+
+          it { is_expected.to eq('alternate') }
+        end
+
+        context 'when theme is not valid' do
+          it { is_expected.to eq('default') }
+        end
+      end
+    end
+  end
+
+  describe '#page_color_scheme' do
+    subject { helper.page_color_scheme }
+
+    context 'when force_color_scheme is present' do
+      before { helper.content_for(:force_color_scheme) { 'value' } }
+
+      it { is_expected.to eq('value') }
+    end
+
+    context 'when force_color_scheme is absent' do
+      it { is_expected.to eq('auto') }
+    end
+  end
+
   private
 
   def html_links