@Service
public class CustomPersistentRememberMeServices extends
    AbstractRememberMeServices {

    private final Logger log = LoggerFactory.getLogger(CustomPersistentRememberMeServices.class);

    // Token is valid for one month
    private static final int TOKEN_VALIDITY_DAYS = 31;

    private static final int TOKEN_VALIDITY_SECONDS = 60 * 60 * 24 * TOKEN_VALIDITY_DAYS;

    private static final int DEFAULT_SERIES_LENGTH = 16;

    private static final int DEFAULT_TOKEN_LENGTH = 16;

    private SecureRandom random;

    @Inject
    private PersistentTokenRepository persistentTokenRepository;

    @Inject
    private UserRepository userRepository;

    @Inject
    public CustomPersistentRememberMeServices(Environment env, org.springframework.security.core.userdetails
        .UserDetailsService userDetailsService) {

        super(env.getProperty("jhipster.security.rememberme.key"), userDetailsService);
        random = new SecureRandom();
    }

    @Override
    @Transactional
    protected UserDetails processAutoLoginCookie(String[] cookieTokens, HttpServletRequest request,
        HttpServletResponse response) {

        PersistentToken token = getPersistentToken(cookieTokens);
        String login = token.getUser().getSteamId();

        // Token also matches, so login is valid. Update the token value, keeping the *same* series number.
        log.debug("Refreshing persistent login token for user '{}', series '{}'", login, token.getSeries());
        token.setTokenDate(LocalDate.now());
        token.setTokenValue(generateTokenData());
        token.setIpAddress(request.getRemoteAddr());
        token.setUserAgent(request.getHeader("User-Agent"));
        try {
            persistentTokenRepository.saveAndFlush(token);
            addCookie(token, request, response);
        } catch (DataAccessException e) {
            log.error("Failed to update token: ", e);
            throw new RememberMeAuthenticationException("Autologin failed due to data access problem", e);
        }
        return getUserDetailsService().loadUserByUsername(login);
    }

    @Override
    protected void onLoginSuccess(HttpServletRequest request, HttpServletResponse response, Authentication
        successfulAuthentication) {

        String steamId = Util.extractSteamId(successfulAuthentication.getName());

        log.debug("Creating new persistent login for user {}", steamId);
        PersistentToken token = userRepository.findOneBySteamId(steamId).map(u -> {
            PersistentToken t = new PersistentToken();
            t.setSeries(generateSeriesData());
            t.setUser(u);
            t.setTokenValue(generateTokenData());
            t.setTokenDate(LocalDate.now());
            t.setIpAddress(request.getRemoteAddr());
            t.setUserAgent(request.getHeader("User-Agent"));
            return t;
        }).orElseThrow(() -> new UsernameNotFoundException("User " + steamId + " was not found in the database"));
        try {
            persistentTokenRepository.saveAndFlush(token);
            addCookie(token, request, response);
        } catch (DataAccessException e) {
            log.error("Failed to save persistent token ", e);
        }
    }

    /**
     * When logout occurs, only invalidate the current token, and not all user sessions.
     * <p/>
     * The standard Spring Security implementations are too basic: they invalidate all tokens for the
     * current user, so when he logs out from one browser, all his other sessions are destroyed.
     */
    @Override
    @Transactional
    public void logout(HttpServletRequest request, HttpServletResponse response, Authentication authentication) {
        String rememberMeCookie = extractRememberMeCookie(request);
        if (rememberMeCookie != null && rememberMeCookie.length() != 0) {
            try {
                String[] cookieTokens = decodeCookie(rememberMeCookie);
                PersistentToken token = getPersistentToken(cookieTokens);
                persistentTokenRepository.delete(token);
            } catch (InvalidCookieException ice) {
                log.info("Invalid cookie, no persistent token could be deleted");
            } catch (RememberMeAuthenticationException rmae) {
                log.debug("No persistent token found, so no token could be deleted");
            }
        }
        super.logout(request, response, authentication);
    }

    /**
     * Validate the token and return it.
     */
    private PersistentToken getPersistentToken(String[] cookieTokens) {
        if (cookieTokens.length != 2) {
            throw new InvalidCookieException("Cookie token did not contain " + 2 +
                " tokens, but contained '" + Arrays.asList(cookieTokens) + "'");
        }
        String presentedSeries = cookieTokens[0];
        String presentedToken = cookieTokens[1];
        PersistentToken token = persistentTokenRepository.findOne(presentedSeries);

        if (token == null) {
            // No series match, so we can't authenticate using this cookie
            throw new RememberMeAuthenticationException("No persistent token found for series id: " + presentedSeries);
        }

        // We have a match for this user/series combination
        log.info("presentedToken={} / tokenValue={}", presentedToken, token.getTokenValue());
        if (!presentedToken.equals(token.getTokenValue())) {
            // Token doesn't match series value. Delete this session and throw an exception.
            persistentTokenRepository.delete(token);
            throw new CookieTheftException("Invalid remember-me token (Series/token) mismatch. Implies previous " +
                "cookie theft attack.");
        }

        if (token.getTokenDate().plusDays(TOKEN_VALIDITY_DAYS).isBefore(LocalDate.now())) {
            persistentTokenRepository.delete(token);
            throw new RememberMeAuthenticationException("Remember-me login has expired");
        }
        return token;
    }

    private String generateSeriesData() {
        byte[] newSeries = new byte[DEFAULT_SERIES_LENGTH];
        random.nextBytes(newSeries);
        return new String(Base64.encode(newSeries));
    }

    private String generateTokenData() {
        byte[] newToken = new byte[DEFAULT_TOKEN_LENGTH];
        random.nextBytes(newToken);
        return new String(Base64.encode(newToken));
    }

    private void addCookie(PersistentToken token, HttpServletRequest request, HttpServletResponse response) {
        setCookie(
            new String[]{token.getSeries(), token.getTokenValue()},
            TOKEN_VALIDITY_SECONDS, request, response);
    }
}