package q5

import (
	"fmt"
	"net"
)

func GetLocalIP() (string, error) {
	interfaces, err := net.Interfaces()
	if err != nil {
		return "", err
	}
	for _, iface := range interfaces {
		if iface.Flags&net.FlagUp == 0 || iface.Flags&net.FlagLoopback != 0 {
			continue
		}
		addrs, err := iface.Addrs()
		if err != nil {
			return "", err
		}
		for _, addr := range addrs {
			ipnet, ok := addr.(*net.IPNet)
			if !ok || ipnet.IP.IsLoopback() {
				continue
			}
			if ipnet.IP.To4() != nil {
				return ipnet.IP.String(), nil
			}
		}
	}

	return "", fmt.Errorf("无法获取本机有效的IP地址")
}