package server

import (
	"errors"
	"log"
	"net"
)

// github.com/insomniacslk/dhcp

type Config struct {
	Device string `yaml:"device"`
}

type Server struct {
	addrs []net.IP
	l     net.Listener
}

func addrsForDevice(dev string) ([]net.IP, error) {
	netInterface, err := net.InterfaceByName(dev)
	if err != nil {
		return nil, err
	}

	var addrs []net.IP
	devAddrs, err := netInterface.Addrs()
	if err != nil {
		return nil, err
	}

	for _, addr := range devAddrs {
		ip := net.ParseIP(addr.String())
		if ip == nil {
			continue // address isn't an IP address
		}

		// DHCP should only listen on private addresses.
		if !ip.IsPrivate() {
			continue
		}

		// only support IPv4 for now
		if len(ip) != 4 {
			continue
		}

		addrs = append(addrs, ip)
	}

	return addrs, nil
}

func NewServer(cfg *Config) (*Server, error) {
	addrs, err := addrsForDevice(cfg.Device)
	if err != nil {
		return nil, err
	}

	log.Println("server IP list: ", addrs)
	return nil, errors.New("not implemented")
}