module AIXM

  ##
  # Geographical coordinates
  #
  # The following notations for longitude and latitude are recognized:
  # * DD - examples: 12.12345678 (north or east), -12.12345678 (south or west)
  # * DMS - examples: 11°22'33.44"N, 1112233.44W
  class XY

    using AIXM::Refinements

    def initialize(lat:, long:)
      @lat, @long = float_for(lat), float_for(long)
      fail(ArgumentError, "illegal latitude") unless (-90..90).include? @lat
      fail(ArgumentError, "illegal longitude") unless (-180..180).include? @long
    end

    def lat(format=nil)
      case format
        when :OFM then ("%.8f" % @lat.abs.round(8)) + (@lat.negative? ? 'S' : 'N')
        when :AIXM then @lat.to_dms(2).gsub(/[^\d.]/, '') + (@lat.negative? ? 'S' : 'N')
        else @lat.round(8)
      end
    end

    def long(format=nil)
      case format
        when :OFM then ("%.8f" % @long.abs.round(8)) + (@long.negative? ? 'W' : 'E')
        when :AIXM then @long.to_dms(3).gsub(/[^\d.]/, '') + (@long.negative? ? 'W' : 'E')
        else @long.round(8)
      end
    end

    def ==(other)
      other.is_a?(XY) && lat == other.lat && long == other.long
    end

    private

    def float_for(value)
      case value
        when Numeric then value.to_f
        when String then value[0..-2].to_dd * (value =~ /[SW]$/ ? -1 : 1)
        else fail(ArgumentError, "illegal value class `#{value.class}'")
      end
    rescue
      fail(ArgumentError, "illegal value `#{value}'")
    end

  end
end