package com.common.aspect;

import com.common.annotation.RequestLimit;
import com.common.core.enums.ResultCodeEnum;
import com.common.core.exception.BizException;
import com.common.core.utils.DateUtils;
import com.common.redis.util.RedisUtil;
import com.common.security.utils.IpUtil;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;
import java.security.SecureRandom;
import java.util.Set;

@Aspect
@Component
@Order(1)
@Slf4j
public class RequestLimitAspect {

    @Autowired
    private RedisUtil redisUtil;

    private static final String REQ_LIMIT = "req_limit:%s:%s:";
    private static final String REQ_LIMIT_FREQUENCY = "req_limit_frequency_%s_%s";

    /**
     * 定义拦截规则：拦截com.springboot.bcode.api包下面的所有类中，有@RequestLimit Annotation注解的方法
     * 。
     */
    @Pointcut("@within(org.springframework.web.bind.annotation.RestController) ")
    public void pointcut() {
    }

    @Around("pointcut()")
    public Object method(ProceedingJoinPoint joinPoint) throws Throwable {
        Object[] args = joinPoint.getArgs();

        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod(); // 获取被拦截的方法
        RequestLimit limt = method.getAnnotation(RequestLimit.class);
        int time,count,size;
        if (limt == null) {
            time = RequestLimit.DEFAULT_TIME;
            count = RequestLimit.DEFAULT_COUNT;
            size = RequestLimit.DEFAULT_SIZE;
        }else{
            time = limt.time();
            count = limt.count();
            size = limt.size();
        }
        HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();


        String ip = IpUtil.getIpAddr(request);
        String url = request.getRequestURI();

        // judge condition
        //大小限制
        if(request.getContentLength() > size*1024*1024){
            throw new BizException(ResultCodeEnum.LARGE_REQUEST_ERROR);
        }
        //频次限制
        String key = String.format(REQ_LIMIT, url, ip);
        Set<String> valueList = redisUtil.getKeys(key + "*");
        //将有效的过滤出来，过期时间在当前时间后的
        if (!CollectionUtils.isEmpty(valueList) && count>-1 && valueList.size() >= count) {
            throw new BizException(ResultCodeEnum.BUSY_REQUEST_ERROR);
        }
        redisUtil.set(key+ new SecureRandom().nextLong(), DateUtils.now().getTime(),time);
        return joinPoint.proceed();
    }
}