package host

import (
	"fmt"
	"lux/proto"
	"net"
)

type LuxOptionType uint

const (
	LuxOptionTypeWAN  = 0
	LuxOptionTypeWAN6 = 1
)

type LuxOption interface {
	Read(rd *proto.LuxBuffer) error
	Write(wd *proto.LuxBuffer)

	Type() LuxOptionType
}

type LuxOptionWAN struct {
	Addr4 net.IP
}

func (opt *LuxOptionWAN) Read(rd *proto.LuxBuffer) error {
	octets, err := rd.ReadNext(4)
	if err != nil {
		return err
	}

	opt.Addr4 = net.IP(octets)
	return nil
}

func (opt *LuxOptionWAN) Write(wd *proto.LuxBuffer) {
	wd.WriteBytes(opt.Addr4.To4())
}

func (*LuxOptionWAN) Type() LuxOptionType {
	return LuxOptionTypeWAN
}

type LuxOptionWAN6 struct {
	Addr6 net.IP
}

func (opt *LuxOptionWAN6) Read(rd *proto.LuxBuffer) error {
	octets, err := rd.ReadNext(16)
	if err != nil {
		return err
	}

	opt.Addr6 = net.IP(octets)
	return nil
}

func (opt *LuxOptionWAN6) Write(wd *proto.LuxBuffer) {
	wd.WriteBytes(opt.Addr6.To16())
}

func (*LuxOptionWAN6) Type() LuxOptionType {
	return LuxOptionTypeWAN6
}

func ReadLuxOption(rd *proto.LuxBuffer) (LuxOption, error) {
	var err error
	optVal, err := rd.ReadUint16()
	if err != nil {
		return nil, err
	}

	switch LuxOptionType(optVal) {
	case LuxOptionTypeWAN:
		opt := &LuxOptionWAN{}
		err = opt.Read(rd)
		return opt, err
	case LuxOptionTypeWAN6:
		opt := &LuxOptionWAN6{}
		err = opt.Read(rd)
		return opt, err
	default:
		return nil, fmt.Errorf("unknown option %d", optVal)
	}
}

func WriteLuxOption(wd *proto.LuxBuffer, opt LuxOption) {
	wd.WriteUint16(uint16(opt.Type()))
	opt.Write(wd)
}