import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;

/**
 * @version v1.0
 * @Description: TODO
 * @Author: cnb
 * @Date: 2020/1/18 23:08
 */
public class IpUtils {

    private static final String[] HEADERS = {
            "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",
            "X-Real-IP"
    };

    /**
     * 判断ip是否为空，空返回true
     * @param ip
     * @return
     */
    public static boolean isEmptyIp(final String ip){
        return (ip == null || ip.length() == 0 || ip.trim().equals("") || "unknown".equalsIgnoreCase(ip));
    }


    /**
     * 判断ip是否不为空，不为空返回true
     * @param ip
     * @return
     */
    public static boolean isNotEmptyIp(final String ip){
        return !isEmptyIp(ip);
    }

    /***
     * 获取客户端ip地址(可以穿透代理)
     * @param request HttpServletRequest
     * @return
     */
    public static String getIpAddress(HttpServletRequest request) {
        String ip = "";
        for (String header : HEADERS) {
            ip = request.getHeader(header);
            if(isNotEmptyIp(ip)) {
                break;
            }
        }
        if(isEmptyIp(ip)){
            ip = request.getRemoteAddr();
        }
        if(isNotEmptyIp(ip) && ip.contains(",")){
            ip = ip.split(",")[0];
        }
        if("0:0:0:0:0:0:0:1".equals(ip)){
            ip = "127.0.0.1";
        }
        return ip;
    }


    /**
     * 获取本机的局域网ip地址，兼容Linux
     * @return String
     * @throws Exception
     */
    public String getLocalHostIP() throws Exception{
        Enumeration<NetworkInterface> allNetInterfaces = NetworkInterface.getNetworkInterfaces();
        String localHostAddress = "";
        while(allNetInterfaces.hasMoreElements()){
            NetworkInterface networkInterface = allNetInterfaces.nextElement();
            Enumeration<InetAddress> address = networkInterface.getInetAddresses();
            while(address.hasMoreElements()){
                InetAddress inetAddress = address.nextElement();
                if(inetAddress != null && inetAddress instanceof Inet4Address){
                    localHostAddress = inetAddress.getHostAddress();
                }
            }
        }
        return localHostAddress;
    }
    
}