package server

import (
	"net"

	log "git.wntrmute.dev/kyle/goutils/log"
	"git.wntrmute.dev/kyle/kdhcp/dhcp"
)

func (srv *Server) WriteDHCPResponse(req *dhcp.Packet, ip net.Addr) error {
	lease := srv.SelectLease(req, srv.clock.Now())
	if lease == nil {
		log.Errln("server: couldn't find available lease")
		return nil
	}

	log.Debugf("available lease: %s", lease)
	response, err := dhcp.NewOffer(req, srv.Config.Network.NetworkInfo(), lease)
	if err != nil {
		log.Errln(err.Error())
		return err
	}

	log.Debugf("building offer for address %s", lease.Addr)
	pkt, err := dhcp.WritePacket(response)
	if err != nil {
		log.Errln(err.Error())
		return err
	}

	ip, err = addrReply(ip)
	if err != nil {
		log.Errln(err.Error())
		return err
	}

	log.Debugf("writing offer to %s", ip)
	_, err = srv.Conn.WriteTo(pkt, ip)
	if err != nil {
		log.Errf("failed to write packet: %s", err)
		return err
	}

	log.Infof("sending offer for address %s to %s", lease.Addr, req.HardwareAddress)
	go func() {
		if err := srv.SaveLeases(); err != nil {
			log.Warningf("server: while saving leases: %s", err)
		}
	}()

	err = srv.AcceptLease(req, lease, srv.clock.Now())
	if err != nil {
		log.Errln(err.Error())
		return err
	}

	return nil
}