module WhiteListHelper

  def self.mattr_accessor_with_default(name, value = nil)
    mattr_accessor name
    self.send("#{name}=", value) if value
  end

  mattr_accessor_with_default :settings, {
      :elements => %w[ a blockquote del ins strong em b i p sub sup small hr br div span h1 h2 h3 h4 h5 h6 ul ol li img u strike object param embed iframe ],
      :attributes => {
        'a'          => %w[href],
        'img'        => %w[src width height alt title],
        'blockquote' => %w[cite],
        'del'        => %w[cite datetime],
        'ins'        => %w[cite datetime],
        :all         => %w[id class style align]
      },
      :protocols  => {
        'a' => {'href' => ['http', 'https', 'mailto', :relative]},
        'img' => {'src'  => ['http', 'https', :relative]}
      }
    }

  def white_list(html)
    Sanitize.clean(html, WhiteListHelper.settings)
  end

end