package proto

import "github.com/pion/stun"

// ReservationToken represents RESERVATION-TOKEN attribute.
//
// The RESERVATION-TOKEN attribute contains a token that uniquely
// identifies a relayed transport address being held in reserve by the
// server. The server includes this attribute in a success response to
// tell the client about the token, and the client includes this
// attribute in a subsequent Allocate request to request the server use
// that relayed transport address for the allocation.
//
// RFC 5766 Section 14.9
type ReservationToken []byte

const reservationTokenSize = 8 // 8 bytes

// AddTo adds RESERVATION-TOKEN to message.
func (t ReservationToken) AddTo(m *stun.Message) error {
	if err := stun.CheckSize(stun.AttrReservationToken, len(t), reservationTokenSize); err != nil {
		return err
	}
	m.Add(stun.AttrReservationToken, t)
	return nil
}

// GetFrom decodes RESERVATION-TOKEN from message.
func (t *ReservationToken) GetFrom(m *stun.Message) error {
	v, err := m.Get(stun.AttrReservationToken)
	if err != nil {
		return err
	}
	if err = stun.CheckSize(stun.AttrReservationToken, len(v), reservationTokenSize); err != nil {
		return err
	}
	*t = v
	return nil
}