class Addressable::URI

def join(uri)
  if !uri.respond_to?(:to_str)
    raise TypeError, "Can't convert #{uri.class} into String."
  end
  if !uri.kind_of?(URI)
    # Otherwise, convert to a String, then parse.
    uri = URI.parse(uri.to_str)
  end
  if uri.to_s.empty?
    return self.dup
  end
  joined_scheme = nil
  joined_user = nil
  joined_password = nil
  joined_host = nil
  joined_port = nil
  joined_path = nil
  joined_query = nil
  joined_fragment = nil
  # Section 5.2.2 of RFC 3986
  if uri.scheme != nil
    joined_scheme = uri.scheme
    joined_user = uri.user
    joined_password = uri.password
    joined_host = uri.host
    joined_port = uri.port
    joined_path = URI.normalize_path(uri.path)
    joined_query = uri.query
  else
    if uri.authority != nil
      joined_user = uri.user
      joined_password = uri.password
      joined_host = uri.host
      joined_port = uri.port
      joined_path = URI.normalize_path(uri.path)
      joined_query = uri.query
    else
      if uri.path == nil || uri.path.empty?
        joined_path = self.path
        if uri.query != nil
          joined_query = uri.query
        else
          joined_query = self.query
        end
      else
        if uri.path[0..0] == SLASH
          joined_path = URI.normalize_path(uri.path)
        else
          base_path = self.path.dup
          base_path = EMPTY_STR if base_path == nil
          base_path = URI.normalize_path(base_path)
          # Section 5.2.3 of RFC 3986
          #
          # Removes the right-most path segment from the base path.
          if base_path.include?(SLASH)
            base_path.sub!(/\/[^\/]+$/, SLASH)
          else
            base_path = EMPTY_STR
          end
          # If the base path is empty and an authority segment has been
          # defined, use a base path of SLASH
          if base_path.empty? && self.authority != nil
            base_path = SLASH
          end
          joined_path = URI.normalize_path(base_path + uri.path)
        end
        joined_query = uri.query
      end
      joined_user = self.user
      joined_password = self.password
      joined_host = self.host
      joined_port = self.port
    end
    joined_scheme = self.scheme
  end
  joined_fragment = uri.fragment
  return self.class.new(
    :scheme => joined_scheme,
    :user => joined_user,
    :password => joined_password,
    :host => joined_host,
    :port => joined_port,
    :path => joined_path,
    :query => joined_query,
    :fragment => joined_fragment
  )
end