module Redlander
  # @api private
  # Uri (for internal use)
  class Uri
    # @api private
    attr_reader :rdf_uri

    # Create Redlander::Uri
    #
    # @param [URI, String] source String or URI object to wrap into Uri.
    # @raise [NotImplementedError] if cannot create a Uri from the given source.
    # @raise [RedlandError] if it fails to create a Uri.
    def initialize(source)
      @rdf_uri = case source
                 when FFI::Pointer
                   wrap(source)
                 when URI, String
                   Redland.librdf_new_uri(Redlander.rdf_world, source.to_s)
                 else
                   raise NotImplementedError, "Cannot create Uri from '#{source.inspect}'"
                 end
      raise RedlandError, "Failed to create Uri from '#{source.inspect}'" if @rdf_uri.null?
      ObjectSpace.define_finalizer(self, proc { Redland.librdf_free_uri(@rdf_uri) })
    end

    def to_s
      Redland.librdf_uri_to_string(@rdf_uri)
    end

    def eql?(other_uri)
      other_uri.is_a?(Uri) && (Redland.librdf_uri_equals(@rdf_uri, other_uri.rdf_uri) != 0)
    end
    alias_method :==, :eql?


    private

    # @api private
    def wrap(u)
      if u.null?
        raise RedlandError, "Failed to create Uri"
      else
        Redland.librdf_new_uri_from_uri(u)
      end
    end
  end
end