module ActionView
  # Prefer controller-specific templates and partials if they exist.
  # Otherwise, use files in the layouts folder.
  class Base
    private
      def full_template_path(template_path, extension)
        # Prefer shared partial first (Rails default)
        shared_path = "#{@base_path}/#{template_path}.#{extension}"
        # Prefer the controller-specific (regular) partial second
        private_path = "#{@base_path}/#{template_path}.#{extension}"
        # Check to see if the partial exists in our "default" folder last
        default_path = ("#{@base_path}/default/#{template_path.split("/")[1]}.#{extension}" rescue private_path)

        if File.exist?(shared_path)
          shared_path
        elsif File.exist?(private_path)
          private_path
        elsif File.exist?(default_path)
          default_path
        else
          # Even though the preferred file doesn't exist, return it
          # so a reasonable error message can be given
          private_path
        end
      end
  end
end