//go:build !linux
// +build !linux

// ^ Linux isn't Unix anyway :P

package arp

import (
	"net"
	"os/exec"
	"strings"
)

func lookup() (map[string]net.HardwareAddr, error) {
	data, err := exec.Command("arp", "-an").Output()
	if err != nil {
		return nil, err
	}

	t := make(map[string]net.HardwareAddr)
	for _, line := range strings.Split(string(data), "\n") {
		fields := strings.Fields(line)
		if len(fields) < 3 {
			continue
		}

		// strip brackets around IP
		ip := strings.ReplaceAll(fields[1], "(", "")
		ip = strings.ReplaceAll(ip, ")", "")

		if mac, err := net.ParseMAC(fields[3]); err == nil {
			t[ip] = mac
		}
	}

	return t, nil
}