package com.adc.da.util;

import org.apache.commons.lang3.StringUtils;

import javax.servlet.http.HttpServletRequest;

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

    private static boolean checkIp(String ip) {
        return ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip);
    }

    public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("X-Forwarded-For");
        if (checkIp(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
            if (checkIp(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }

            if (checkIp(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }

            if (checkIp(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }

            if (checkIp(ip)) {
                ip = request.getRemoteAddr();
            }
        } else if (ip.length() > 15) {
            String[] ips = ip.split(",");

            for(int index = 0; index < ips.length; ++index) {
                String strIp = ips[index];
                if (!"unknown".equalsIgnoreCase(strIp)) {
                    ip = strIp;
                    break;
                }
            }
        }

        return StringUtils.trim(ip);
    }
}