require 'rack/utils'
require 'uri'

module Vinz
  class Url
    def initialize(uri, crypto)
      @uri = uri.is_a?(String) ? URI.parse(uri) : uri
      @crypto = crypto
      @param_key = '_creq'
    end

    def pack(message)
      uri = @uri.clone
      query = Rack::Utils.parse_nested_query(uri.query)
      query[@param_key] = @crypto.encode(message)
      uri.query = Rack::Utils.build_nested_query(query)
      uri
    end

    def unpack
      query = Rack::Utils.parse_nested_query(@uri.query)
      @crypto.decode(query[@param_key])
    end
  end
end