@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface RateLimit {

    //默認最大訪問次數
    int value() default 3;

    //默認時間窗口(秒)
    long duration() default 60;
}

@Slf4j
public class RateLimitInterceptor implements HandlerInterceptor {

    private ConcurrentHashMap<String,Long> requestCountMap = new ConcurrentHashMap<>();

    @Override
    public boolean preHandle(@NotNull HttpServletRequest request, @NotNull HttpServletResponse response, @NotNull Object handler) throws Exception {
        if (handler instanceof HandlerMethod){
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            RateLimit rateLimitAnnotation = handlerMethod.getMethod().getAnnotation(RateLimit.class);
            if (rateLimitAnnotation != null){
                long duration = rateLimitAnnotation.duration();
                int maxRequest = rateLimitAnnotation.value();
                String ipAddress = getClientIpAddress(request);
                String key = ipAddress + ":" + request.getRequestURI();

                //獲取上一次請求的時間戳
                Long lastAccessTime = requestCountMap.getOrDefault(key, 0L);
                //獲取當前請求的時間戳
                long currentAccessTime = System.currentTimeMillis();
                //計算時間間隔
                long timeInterval = TimeUnit.MILLISECONDS.toSeconds(currentAccessTime - lastAccessTime);
                //是否超過時間間隔
                if (timeInterval < duration){
                    //檢查訪問次數是否超過限制
                    if (requestCountMap.getOrDefault(key + "_count",0L) > maxRequest){
                        response.getWriter().write("訪問頻率超過限制");
                        response.setStatus(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
                        return false;
                    }
                }else {
                    //重置訪問時間和訪問次數
                    requestCountMap.put(key,currentAccessTime);
                    requestCountMap.put(key + "_count",0L);
                }
                //訪問次數 + 1
                requestCountMap.put(key + "_count",requestCountMap.getOrDefault(key + "_count",0L) + 1);
            }
        }
        return true;
    }

    private String getClientIpAddress(HttpServletRequest request) {
        // 獲取客戶端IP地址的方法實現，可以根據具體的需求自行實現
        // 例如，可以通過HttpServletRequest對象獲取IP地址
        // return request.getRemoteAddr();
        return "127.0.0.1"; // 這里僅作示例，假設IP地址為本地地址
    }
}

@Configuration
public class MyConfig  implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new RateLimitInterceptor());
    }
}

    /**
     * 通過id查詢項目任務書
     * @param id id
     * @return R
     */
    @Operation(summary = "通過id查詢", description = "通過id查詢")
    @GetMapping("/{id}" )
    @RateLimit
    public R getById(@PathVariable("id" ) String id) {
        return R.ok(prjAssignService.getByIdAssign(id));
    }