before_validation :normalize_color_fields

  private

  # could use refactoring to reduce redundancy
  def normalize_color_fields
    (1..3).each do |number|
      normalize_field("color#{number}")
    end
  end

  def normalize_field(name)
    return unless if attribute_present?(name)
    content = send(name)
    content.gsub!(/[^0-9A-F]/i, "")
    send("#{name}=", content)
  end