m_state = boost::lexical_cast<std::string>(uuid);

	url += "&state=" + Util::urlencode(m_state);

	return url;

}

std::string OAuth2::requestToken(const std::string &code, std::string &token, std::string &bot_token) {

	std::string url = m_tokenURL + "?";

	url += "client_id=" + Util::urlencode(m_clientId);

	url += "&client_secret=" + Util::urlencode(m_clientSecret);

	url += "&code=" + Util::urlencode(code);

	if (!m_redirectURL.empty()) {

		url += "&redirect_uri=" + Util::urlencode(m_redirectURL);

	}

	rapidjson::Document resp;

	HTTPRequest req(HTTPRequest::Get, url);

	if (!req.execute(resp)) {

		LOG4CXX_ERROR(logger, url);

		LOG4CXX_ERROR(logger, req.getError());

		return req.getError();

	}

	rapidjson::Value& access_token = resp["access_token"];

	if (!access_token.IsString()) {

		LOG4CXX_ERROR(logger, "No 'access_token' object in the reply.");

		LOG4CXX_ERROR(logger, url);

		LOG4CXX_ERROR(logger, req.getRawData());

		return "No 'access_token' object in the reply.";

	}

	token = access_token.GetString();

	if (token.empty()) {

		LOG4CXX_ERROR(logger, "Empty 'access_token' object in the reply.");

		LOG4CXX_ERROR(logger, url);

		LOG4CXX_ERROR(logger, req.getRawData());

		return "Empty 'access_token' object in the reply.";

	}

	rapidjson::Value& bot = resp["bot"];

	if (bot.IsObject()) {

			bot_token = bot_access_token.GetString();

		}

	}

	return "";

}

}