FEATURE: support user local switching to RTL correctly

FEATURE: support RTL in multisite

app/assets/stylesheets/desktop_rtl.scss

@@ -0,0 +1,2 @@
+// stub file used to clean up asset precompilation process
+@import "desktop";

app/assets/stylesheets/mobile_rtl.scss

@@ -0,0 +1,2 @@
+// stub file used to clean up asset precompilation process
+@import "mobile";

app/helpers/application_helper.rb

@@ -106,6 +106,16 @@ module ApplicationHelper
     current_user.try(:staff?)
   end
 
+  def rtl?
+    ["ar", "fa_IR", "he"].include?(user_locale)
+  end
+
+  def user_locale
+    locale = current_user.locale if current_user && SiteSetting.allow_user_locale
+    # changing back to default shoves a blank string there
+    locale.present? ? locale : SiteSetting.default_locale
+  end
+
   # Creates open graph and twitter card meta data
   def crawlable_meta_data(opts=nil)
 

app/views/common/_discourse_stylesheet.html.erb

@@ -1,4 +1,8 @@
-<%= DiscourseStylesheets.stylesheet_link_tag(mobile_view? ? :mobile : :desktop) %>
+<%- if rtl? %>
+  <%= DiscourseStylesheets.stylesheet_link_tag(mobile_view? ? :mobile_rtl : :desktop_rtl) %>
+<%- else %>
+  <%= DiscourseStylesheets.stylesheet_link_tag(mobile_view? ? :mobile : :desktop) %>
+<%- end %>
 
 <%- if staff? %>
   <%= stylesheet_link_tag "admin"%>

lib/sass/discourse_sass_compiler.rb

@@ -63,10 +63,8 @@ class DiscourseSassCompiler
       }
     }.merge(debug_opts)).render
 
-    # Check if CSS needs to be RTLed after compilation
-    # and run R2 gem on compiled CSS if true and R2 gem is available
     css_output = css
-    if !SiteSetting.allow_user_locale && SiteSetting.default_locale.in?(%w(he ar fa_IR))
+    if opts[:rtl]
       begin
         require 'r2'
         css_output = R2.r2(css) if defined?(R2)

lib/sass/discourse_stylesheets.rb

@@ -91,8 +91,9 @@ class DiscourseStylesheets
     end
 
     scss = File.read("#{Rails.root}/app/assets/stylesheets/#{@target}.scss")
+    rtl = @target.to_s =~ /_rtl$/
     css = begin
-      DiscourseSassCompiler.compile(scss, @target)
+      DiscourseSassCompiler.compile(scss, @target, rtl: rtl)
     rescue Sass::SyntaxError => e
       Rails.logger.error "Stylesheet failed to compile for '#{@target}'! Recompiling without plugins and theming."
       Rails.logger.error e.sass_backtrace_str("#{@target} stylesheet")

lib/tasks/assets.rake

@@ -78,7 +78,7 @@ task 'assets:precompile:css' => 'environment' do
     # css will get precompiled during first request instead in that case.
     if ActiveRecord::Base.connection.table_exists?(ColorScheme.table_name)
       puts "Compiling css for #{db}"
-      [:desktop, :mobile].each do |target|
+      [:desktop, :mobile, :desktop_rtl, :mobile_rtl].each do |target|
         puts DiscourseStylesheets.compile(target)
       end
     end