package server

import (
	"fmt"
	"net"

	"git.wntrmute.dev/kyle/kdhcp/bazel-kdhcp/external/com_github_davecgh_go_spew/spew"
	"git.wntrmute.dev/kyle/kdhcp/log"
)

type addr struct {
	ifi *net.Interface
	IP  net.IP
	ipn *net.IPNet
}

func addrsForDevice(dev string) ([]addr, error) {
	netInterface, err := net.InterfaceByName(dev)
	if err != nil {
		return nil, fmt.Errorf("while selecting interface %s: %w", dev, err)
	}

	spew.Dump(netInterface)

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

	for _, devAddr := range devAddrs {
		log.Debugf("consider %s", devAddr.String())
		ip, ipn, err := net.ParseCIDR(devAddr.String())
		if err != nil {
			continue
		}

		if ip == nil {
			continue // address isn't an IP address
		}

		log.Debugf("found IP: %s", ip)
		ip = ip.To4()

		// DHCP should only listen on private addresses.
		if !ip.IsPrivate() {
			log.Debugln("skipping non-private")
			continue
		}

		// only support IPv4 for now
		if len(ip) != 4 {
			log.Debugf("%d IP, only supporting v4 right now", len(ip))
			continue
		}

		addrs = append(addrs, addr{netInterface, ip, ipn})
	}

	return addrs, nil
}