package device

import (
	"net"
	"os"
	"strings"
)

// GetDeviceID 返回本机原始唯一ID（Linux /etc/machine-id 或 hostname+MAC）
func GetDeviceID() string {
	// 尝试读取 Linux /etc/machine-id
	if data, err := os.ReadFile("/etc/machine-id"); err == nil {
		s := strings.TrimSpace(string(data))
		if s != "" {
			return s
		}
	}

	// fallback: hostname + first non零MAC
	hn, _ := os.Hostname()
	mac := getFirstMac()
	return hn + "|" + mac
}

func getFirstMac() string {
	ifaces, err := net.Interfaces()
	if err != nil {
		return ""
	}
	for _, it := range ifaces {
		if len(it.HardwareAddr) == 0 {
			continue
		}
		mac := it.HardwareAddr.String()
		if mac != "" && mac != "00:00:00:00:00:00" {
			return mac
		}
	}
	return ""
}