package simple.cloud.config.myInterceptor;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import net.sf.json.JSONArray;
import simple.cloud.components.common.params.ResponseParams;
import simple.cloud.components.common.utils.MyUtils;
@Component
@CrossOrigin("*")
public class MyInterceptor implements HandlerInterceptor {
	@Resource 
	private RedisTemplate<String, Object> redisTemplate;
	/**
	 * 1、過濾封禁IP 
     * 2、過濾惡意IP
	 */
	@Override
	@CrossOrigin("*")
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		if (handler.getClass().isAssignableFrom(HandlerMethod.class)) { // 判斷此class對象所表示的類或接口與指定的class參數(shù)所表示的類或接口是否相同
			//1、校驗IP合法
			String ip = MyUtils.getIpAddress(request);
			String limitKey = request.getServletPath() + MyUtils.getIpAddress(request);
			Object blackIp = redisTemplate.opsForValue().get(ip);
			if (MyUtils.isNotNull(blackIp)) {
				respouseOut(response, ResponseParams.error("禁止使用！"));
				return false;
			}
			//2、校驗重復(fù)點擊
//          HandlerMethod封裝方法定義相關(guān)的信息，如類、方法、參數(shù)等
			HandlerMethod handlerMethod = (HandlerMethod) handler;
			Method method = handlerMethod.getMethod();
//           獲取方法中是否包含注解
			MyLimit methodAnnotation = method.getAnnotation(MyLimit .class);
//           獲取類中是否包含注解
			MyLimit classAnnotation = method.getDeclaringClass().getAnnotation(MyLimit .class);
//           如果方法上有注解 就優(yōu)先選擇方法上的參數(shù)
			MyLimit myLimit = methodAnnotation != null ? methodAnnotation : classAnnotation;
			if (requestLimit != null) {
				if (checkLimit(limitKey, myLimit )) {
					respouseOut(response, ResponseParams.error("您點擊的太頻繁啦！"));
                    //將被封禁的IP加入緩存，下次訪問時不必校驗其點擊情況
					redisTemplate.opsForValue().set(ip  , 1, 30, TimeUnit.SECONDS);
					return false;
				}
			}
		}
		return true;
	}
	/**
	 * 回寫給客戶端
	 */
	private void respouseOut(HttpServletResponse response, ResponseParams resp) throws IOException {
		response.setCharacterEncoding("UTF-8");
		response.setContentType("application/json;charaset=utf-8");
		PrintWriter out = null;
		String json = com.alibaba.fastjson.JSONObject.toJSON(resp).toString();
		out = response.getWriter();
		out.append(json);
	}
	/**
	 * 判斷請求是否受限
	 */
	private boolean checkLimit(String limitKey, RequestLimit requestLimit) {
        //使用IP+請求地址作為key
        //從緩存中獲取，當(dāng)前這個請求訪問了幾次
		Integer redisCount = (Integer) redisTemplate.opsForValue().get(limitKey);
		if (redisCount == null) {
            //初始次數(shù)
			redisTemplate.opsForValue().set(limitKey, 1, requestLimit.second(), TimeUnit.SECONDS);
		} else {
            //若在指定時間內(nèi)超過了訪問次數(shù)限制，則返回true
			if (redisCount.intValue() >= requestLimit.maxCount()) {
			   //將其設(shè)置超過限制次數(shù)，并延遲30秒，30秒之后可以重新訪問
			   redisTemplate.opsForValue().set(limitKey, requestLimit.maxCount()+1, 30, TimeUnit.SECONDS);
				return true;
			}
            //次數(shù)自增
			redisTemplate.opsForValue().increment(limitKey, 1);
		}
		return false;
	}
}

@Documented
@Inherited
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyLimit {
    int second() default 1;
    int maxCount() default 15;
}

@Resource
    private MyInterceptor myInterceptor;
	/**
	 * 讓cors高于攔截器的權(quán)限
	 * 解決攔截器CROS問題
	 * @return
	 */
    @Bean
    public CorsFilter corsFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedOrigin("*");
        config.setAllowCredentials(true);
        config.addAllowedMethod("*");
        config.addAllowedHeader("*");
        UrlBasedCorsConfigurationSource configSource = new UrlBasedCorsConfigurationSource();
        configSource.registerCorsConfiguration("/**", config);
        return new CorsFilter(configSource);
    }
    /**
     * 添加我的默認(rèn)的攔截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor).addPathPatterns("/**");
    }