package com.cloudroam.common.util;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;

/**
 * @author Gadfy
 * IP工具类
 */
@Slf4j
public class IPUtil {

    private IPUtil() {
        throw new IllegalStateException("Utility class");
    }

    private static final String[] IP_HEADER_CANDIDATES = {
            "X-Forwarded-For",
            "Proxy-Client-IP",
            "WL-Proxy-Client-IP",
            "HTTP_X_FORWARDED_FOR",
            "HTTP_X_FORWARDED",
            "HTTP_X_CLUSTER_CLIENT_IP",
            "HTTP_CLIENT_IP",
            "HTTP_FORWARDED_FOR",
            "HTTP_FORWARDED",
            "HTTP_VIA",
            "REMOTE_ADDR"
    };

    public static String getIPFromRequest(HttpServletRequest request) {
        if (request == null) {
            if (null == RequestContextHolder.getRequestAttributes()) {
                return null;
            }
            request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        }

        for (String header : IP_HEADER_CANDIDATES) {
            String ipList = request.getHeader(header);
            if (ipList != null && ipList.length() != 0 && !"unknown".equalsIgnoreCase(ipList)) {
                log.debug("ipList.split(\",\")[0]::{}", ipList.split(",")[0]);
                return ipList.split(",")[0];
            }
        }

        log.debug("request.getRemoteAddr()::{}", request.getRemoteAddr());
        return request.getRemoteAddr();
    }
}