module BitmaskAttrAccessor
  def bitmask_attr_accessor(accessor_name, bitmask_name, options)

    define_method("#{accessor_name}=") do |values|
      values = [*values].map { |value| value.to_sym }
      bitmask_value = (values & options)
        .map { |value| 2**options.index(value) }
        .inject(0, :+)
      send("#{bitmask_name}=", bitmask_value)
    end

    define_method(accessor_name) do
      bitmask_value = send(bitmask_name).to_i || 0
      options.reject do |option|
        (bitmask_value & 2**options.index(option)).zero?
      end
    end

  end
end