nofxx/georuby

module GeoRuby
  module SimpleFeatures
    # Creates a new geometry according to constructions
    # received from a parser, for example EWKBParser.
    class GeometryFactory
      # the built geometry
      attr_reader :geometry

      def initialize
        @geometry = nil
        @geometry_stack = []
      end

      # resets the factory
      def reset
        @geometry = nil
        @geometry_stack = []
      end

      # add a 2D point to the current geometry
      def add_point_x_y(x, y)
        @geometry_stack.last.set_x_y(x, y)
      end

      # add 2D points to the current geometry
      def add_points_x_y(xy)
        xy.each_slice(2) { |slice| add_point_x_y(*slice) }
      end

      # add a 3D point to the current geometry
      def add_point_x_y_z(x, y, z)
        @geometry_stack.last.set_x_y_z(x, y, z)
      end

      # add 3D points to the current geometry
      def add_points_x_y_z(xyz)
        xyz.each_slice(3) { |slice| add_point_x_y_z(*slice) }
      end

      # add a 2D point with M to the current geometry
      def add_point_x_y_m(x, y, m)
        @geometry_stack.last.set_x_y(x, y)
        @geometry_stack.last.m = m
      end

      # add 2D points with M to the current geometry
      def add_points_x_y_m(xym)
        xym.each_slice(3) { |slice| add_point_x_y_m(*slice) }
      end

      # add a 3D point with M to the current geometry
      def add_point_x_y_z_m(x, y, z, m)
        @geometry_stack.last.set_x_y_z(x, y, z)
        @geometry_stack.last.m = m
      end

      # add 3D points with M to the current geometry
      def add_points_x_y_z_m(xyzm)
        xyzm.each_slice(4) { |slice| add_point_x_y_z_m(*slice) }
      end

      # begin a geometry of type +geometry_type+
      def begin_geometry(geometry_type, srid = DEFAULT_SRID)
        geometry = geometry_type.new(srid)
        @geometry = geometry if @geometry.nil?
        @geometry_stack << geometry
      end

      # terminates the current geometry
      def end_geometry(with_z = false, with_m = false)
        @geometry = @geometry_stack.pop
        @geometry.with_z = with_z
        @geometry.with_m = with_m
        # add the newly defined geometry to its parent if there is one
        @geometry_stack.last << geometry unless @geometry_stack.empty?
      end

      # abort a geometry
      def abort_geometry
        reset
      end
    end
  end
end