svoop/aixm

using AIXM::Refinements

module AIXM

  # Rectangle shape composed of two lengths
  #
  # @examples
  #   AIXM.r(AIXM.d(25, :m), AIXM.d(20, :m))   # rectangle
  #   AIXM.r(AIXM.d(25, :m))                   # square
  class R
    include AIXM::Concerns::HashEquality

    # Rectangle length
    #
    # @overload length
    #   @return [AIXM::D]
    # @overload length=(value)
    #   @param value [AIXM::D]
    attr_reader :length

    # Rectangle width
    #
    # @overload width
    #   @return [AIXM::D]
    # @overload width=(value)
    #   @param value [AIXM::D]
    attr_reader :width

    # See the {overview}[AIXM::R] for examples.
    def initialize(length, width=nil)
      self.length, self.width = length, (width || length)
    end

    # @return [String]
    def inspect
      %Q(#<#{self.class} #{to_s}>)
    end

    # @return [String] human readable representation (e.g. "25.0 m x 20.0 m")
    def to_s
      [length, width].join(' x ')
    end

    %i(length width).each do |dimension|
      define_method("#{dimension}=") do |value|
        fail(ArgumentError, "invalid dimension") unless value.is_a? AIXM::D
        instance_variable_set(:"@#{dimension}", value)
        @length, @width = @width, @length if @length && @width && @length < @width
      end
    end

    # Calculate the surface in square meters.
    #
    # @return [Float]
    def surface
      length.to_m.dim * width.to_m.dim
    end

    # @see Object#==
    def ==(other)
      self.class === other && length == other.length && width == other.width
    end

  end
end