/**
 * @ProjectName: cdkj-framework
 * @Package: com.cdkjframework.core.spring.filter
 * @ClassName: FilterHandlerInterceptor
 * @Description: 攔截過濾
 * @Author: xiaLin
 * @Date: 2022/6/22 13:36
 * @Version: 1.0
 */
public class FilterHandlerInterceptor implements HandlerInterceptor {

  /**
   * 日志
   */
  private LogUtils logUtils = LogUtils.getLogger(FilterHandlerInterceptor.class);

  /**
   * redis鎖
   */
  private final RedisLettuceLock redisLettuceLock;

  /**
   * IP頭部變量(可能通過Nginx代理后)
   */
  private static final String HEADER_IP = "X-Real-IP";

  /**
   * 鎖IP請求URL地址KEY
   */
  private static final String LOCK_IP_URL_KEY = "lock_ip_";

  /**
   * IP請求URL地址時間
   */
  private static final String IP_URL_REQ_TIME = "ip_url_times_";

  /**
   * 極限時間
   */
  private static final long LIMIT_TIMES = 5;

  /**
   * IP鎖定時間 秒
   */
  private static final int IP_LOCK_TIME = 60;

  /**
   * 構建函數
   */
  public FilterHandlerInterceptor(RedisLettuceLock redisLettuceLock) {
    this.redisLettuceLock = redisLettuceLock;
  }

  /**
   * 預處理
   *
   * @param request  請求
   * @param response 響應
   * @param o        參數
   * @return 返回結果
   * @throws Exception 異常信息
   */
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
    String ip = request.getHeader(HEADER_IP);
    if (StringUtils.isNullAndSpaceOrEmpty(ip)) {
      ip = request.getRemoteAddr();
    }
    logUtils.info("request 請求地址 Uri={}，ip={}", request.getRequestURI(), ip);
    if (ipIsLock(ip)) {
      logUtils.info("ip訪問被禁止={}", ip);
      ResponseBuilder builder = ResponseBuilder.failBuilder("ip訪問被禁止");
      returnJson(response, builder);
      return false;
    }
    if (!addRequest(ip, request.getRequestURI())) {
      ResponseBuilder builder = ResponseBuilder.failBuilder("ip訪問被禁止");
      returnJson(response, builder);
      return false;
    }
    return true;
  }

  @Override
  public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

  }

  @Override
  public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

  }

  /**
   * IP 是否已鎖
   *
   * @param ip IP 地址
   * @return 返回是否成功
   */
  private Boolean ipIsLock(String ip) {
    if (redisLettuceLock.lock(LOCK_IP_URL_KEY + ip)) {
      return true;
    }
    return false;
  }

  /**
   * 添加請求信息
   *
   * @param ip  IP 地址
   * @param uri 請求路徑
   * @return 返回是否成功
   */
  private Boolean addRequest(String ip, String uri) {
    String key = IP_URL_REQ_TIME + ip + uri;
    if (RedisUtils.syncExists(key)) {
      long time = RedisUtils.syncIncr(key, IntegerConsts.ONE);
      if (time >= LIMIT_TIMES) {
        redisLettuceLock.lock(LOCK_IP_URL_KEY + ip, IP_LOCK_TIME, ip);
        return false;
      }
    } else {
      redisLettuceLock.lock(key, (long) IntegerConsts.ONE, IntegerConsts.ONE);
    }
    return true;
  }

  /**
   * 返回結果
   *
   * @param response 響應
   * @param builder  返回結果
   * @throws Exception 異常信息
   */
  private void returnJson(HttpServletResponse response, ResponseBuilder builder) throws Exception {
    ResponseUtils.out(response, builder);
  }
}

/**
 * @ProjectName: cdkj-framework
 * @Package: com.cdkjframework.core.spring.filter
 * @ClassName: WebMvcFilterConfigurerAdapter
 * @Description: java類作用描述
 * @Author: xiaLin
 * @Date: 2022/6/22 13:37
 * @Version: 1.0
 */
@RequiredArgsConstructor
public class WebMvcFilterConfigurerAdapter implements WebMvcConfigurer {

    /**
     * redis鎖
     */
    private final RedisLettuceLock redisLettuceLock;

    /**
     * 過慮句柄攔截器
     *
     * @return 返回攔截器
     */
    @Bean
    private FilterHandlerInterceptor filterHandlerInterceptor() {
        return new FilterHandlerInterceptor(redisLettuceLock);
    }

    /**
     * 添加 攔截器
     *
     * @param registry 攔截器注冊
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(filterHandlerInterceptor()).addPathPatterns("/**");
    }
}