module RCAP
  module CAP_1_2
    # A Circle object is valid if
    # * it has a valid lattitude and longitude
    # * it has a radius with a value greater than zero
    class Circle < Point
      include Validation

      # Expresed in kilometers
      attr_accessor( :radius )

      validates_presence_of( :radius )
      validates_numericality_of( :radius , greater_than_or_equal: 0 )

      XML_ELEMENT_NAME = 'circle' # :nodoc:

      XPATH = 'cap:circle' # :nodoc:

      def initialize( attributes = {} )
        super( attributes )
        @radius = attributes[ :radius ]
      end

      # Returns a string representation of the circle of the form
      #  lattitude,longitude,radius
      def to_s  # :nodoc:
        "#{ self.lattitude },#{ self.longitude } #{ self.radius }"
      end

      def inspect # :nodoc:
        "(#{ self.to_s })"
      end

      def to_xml_element # :nodoc:
        xml_element = REXML::Element.new( XML_ELEMENT_NAME )
        xml_element.add_text( self.to_s )
        xml_element
      end

      def to_xml # :nodoc:
        self.to_xml_element.to_s
      end

      def self.parse_circle_string( circle_string ) # :nodoc:
        coordinates, radius = circle_string.split( ' ' )
        lattitude, longitude = coordinates.split( ',' )
        [ lattitude, longitude, radius ].map{ |e| e.to_f }
      end

      def self.from_xml_element( circle_xml_element ) # :nodoc:
        lattitude, longitude, radius = self.parse_circle_string( circle_xml_element.text )
        circle = self.new( :lattitude => lattitude,
                          :longitude => longitude,
                          :radius => radius )
      end

      # Two circles are equivalent if their lattitude, longitude and radius are equal.
      def ==( other )
        [ self.lattitude, self.longitude, self.radius ] == [ other.lattitude, other.longitude, other.radius ]
      end

      def self.from_yaml_data( circle_yaml_data ) # :nodoc:
        lattitude, longitude,radius = circle_yaml_data
        self.new( :lattitude => lattitude, :longitude => longitude, :radius => radius )
      end

      RADIUS_KEY    = 'radius' # :nodoc:
      LATTITUDE_KEY = 'lattitude' # :nodoc:
      LONGITUDE_KEY = 'longitude' # :nodoc:
      def to_h # :nodoc:
        RCAP.attribute_values_to_hash( [ RADIUS_KEY, self.radius ],
                                      [ LATTITUDE_KEY, self.lattitude ],
                                      [ LONGITUDE_KEY, self.longitude ])
      end

      def self.from_h( circle_hash ) # :nodoc:
        self.new( :radius => circle_hash[ RADIUS_KEY ], :lattitude => circle_hash[ LATTITUDE_KEY ], :longitude => circle_hash[ LONGITUDE_KEY ])
      end
    end
  end
end