class Rails::MailersController

def preview
  if params[:path] == @preview.preview_name
    @page_title = "Mailer Previews for #{@preview.preview_name}"
    render action: "mailer"
  else
    @email_action = File.basename(params[:path])
    if @preview.email_exists?(@email_action)
      @page_title = "Mailer Preview for #{@preview.preview_name}##{@email_action}"
      @email = @preview.call(@email_action, params)
      if params[:part]
        part_type = Mime::Type.lookup(params[:part])
        if part = find_part(part_type)
          response.content_type = part_type
          render plain: part.respond_to?(:decoded) ? part.decoded : part
        else
          raise AbstractController::ActionNotFound, "Email part '#{part_type}' not found in #{@preview.name}##{@email_action}"
        end
      else
        @part = find_preferred_part(request.format, Mime[:html], Mime[:text])
        render action: "email", layout: false, formats: [:html]
      end
    else
      raise AbstractController::ActionNotFound, "Email '#{@email_action}' not found in #{@preview.name}"
    end
  end
end