ThemeHelper.render_theme_with_context

app/controllers/user_controller.rb

@@ -1,4 +1,6 @@
 class UserController < ApplicationController
+  include ThemeHelper
+
   before_filter :authenticate_user!, only: %w(edit update edit_privacy update_privacy data)
 
   def show
@@ -92,15 +94,7 @@ class UserController < ApplicationController
   def data
   end
 
-  SCSS_STYLE = if Rails.env == 'production'
-    :compressed
-  else
-    :compact
-  end.freeze
-
   def theme
-    txt = render_to_string 'user/theme.css.scss', formats: [:erb]
-    sass = Sass::Engine.new txt, style: SCSS_STYLE, cache: false, load_paths: [], syntax: :scss
-    render body: sass.render.to_s, content_type: 'text/css'
+    render body: render_theme_with_context, content_type: 'text/css'
   end
 end

app/helpers/theme_helper.rb

@@ -0,0 +1,31 @@
+module ThemeHelper
+  def render_theme_with_context(context = {})
+    klass = Class.new do
+      def initialize(hash = {})
+        if hash.is_a? ActiveRecord::Base
+          hash = hash.serializable_hash
+        end
+
+        if hash.is_a? Hash
+          hash.each do |k, v|
+            self.instance_variable_set "@#{k}", v
+          end
+        end
+      end
+
+      def render
+        style = if Rails.env == 'production'
+          :compressed
+        else
+          :compact
+        end.freeze
+
+        erb = ERB.new File.read Rails.root.join 'app/views/user/theme.css.scss.erb'
+        sass = Sass::Engine.new erb.result(binding), style: style, cache: false, load_paths: [], syntax: :scss
+        return sass.render.to_s
+      end
+    end
+
+    return klass.new(context).render
+  end
+end

app/views/user/theme.css.scss.erb

@@ -1,3 +1,5 @@
+// TODO: Use canonical colours rather than this test midnight scheme.
+
 // PRIMARY COLOR
 $primary_color:  <%= @primary_color  || "#222222" %>;
 $primary_border: <%= @primary_border || "#151515" %>;
@@ -28,6 +30,7 @@ $color_color:  <%= @color_color  || "#222222" %>;
 $color_border: <%= @color_border || "#151515" %>;
 $color_text:   <%= @color_text   || "#eeeeee" %>;
 
+// PANEL COLORS
 
 // AUXILIARY COLOR
 $link_color:       <%= @link_color       || "#111111" %>;