package weigo

/*
函数都写在这儿
*/
import (
	"errors"
	"fmt"
	"net"
	"os"
)

/**
获取IP地址
*/
func GetIP() string {
	ip, err := externalIP()
	if err != nil {
		return GetIP2()
		fmt.Println(err)
	}

	return ip.String()
}

func GetIP2() string {
	var ip = ""
	address, err := net.InterfaceAddrs()

	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	for _, address := range address {

		// 检查ip地址判断是否回环地址
		if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
			if ipnet.IP.To4() != nil {
				ip = ipnet.IP.String()
			}

		}
	}

	return ip
}

func externalIP() (net.IP, error) {
	ifaces, err := net.Interfaces()
	if err != nil {
		return nil, err
	}
	for _, iface := range ifaces {
		if iface.Flags&net.FlagUp == 0 {
			continue // interface down
		}
		if iface.Flags&net.FlagLoopback != 0 {
			continue // loopback interface
		}
		addrs, err := iface.Addrs()
		if err != nil {
			return nil, err
		}
		for _, addr := range addrs {
			ip := getIpFromAddr(addr)
			if ip == nil {
				continue
			}
			return ip, nil
		}
	}
	return nil, errors.New("connected to the network?")
}

func getIpFromAddr(addr net.Addr) net.IP {
	var ip net.IP
	switch v := addr.(type) {
	case *net.IPNet:
		ip = v.IP
	case *net.IPAddr:
		ip = v.IP
	}
	if ip == nil || ip.IsLoopback() {
		return nil
	}
	ip = ip.To4()
	if ip == nil {
		return nil // not an ipv4 address
	}

	return ip
}