String accessToken = resolveAccessToken(response, accessTokenHeader);

String role = tokenProvider.getRole(accessToken);
UserDetails userDetails;

if (String.valueOf(Role.GUEST).equals(role)) {
    Long guestId = tokenProvider.getUserId(accessToken);
    GuestUser guestUser = guestUserService.getGuestUser(guestId);
    userDetails = new GuestUserDetails(guestUser);
} else {
    String username = tokenProvider.getUsername(accessToken);
    userDetails = userDetailsService.loadUserByUsername(username);
}

    @GetMapping("/info")
    public Object info(@AuthenticationPrincipal UserDetails userDetails) {

        if(userDetails instanceof GuestUserDetails)
            return GuestUser.builder()
                .guestId(((GuestUserDetails) userDetails).getGuestId())
                .guestNickname(userDetails.getUsername())
                .build();
        else if(userDetails instanceof SecurityUserDetails)
            return User.builder()
                .userId(((SecurityUserDetails) userDetails).getUserId())
                .email(userDetails.getUsername())
                .build();