package pdu

import "encoding/binary"

type (
	PDU interface {
		EncodeInto(*[]uint8)
		Encode() []uint8
		Decode([]uint8)
		Size() uint32
	}

	PDU_HEADER struct {
		command_length  uint32
		command_id      uint32
		command_status  uint32
		sequence_number uint32
	}

	GENERIC_NACK struct {
		PDU_HEADER
	}
)

func (p *PDU_HEADER) Encode() []uint8 {
	buf := make([]uint8, 16)
	binary.BigEndian.PutUint32(buf[0:4], p.command_length)
	binary.BigEndian.PutUint32(buf[4:8], p.command_id)
	binary.BigEndian.PutUint32(buf[8:12], p.command_status)
	binary.BigEndian.PutUint32(buf[12:16], p.sequence_number)
	return buf
}
func (p *PDU_HEADER) EncodeInto(buf *[]uint8) {
	bufVal := *buf
	binary.BigEndian.PutUint32(bufVal[0:4], p.command_length)
	binary.BigEndian.PutUint32(bufVal[4:8], p.command_id)
	binary.BigEndian.PutUint32(bufVal[8:12], p.command_status)
	binary.BigEndian.PutUint32(bufVal[12:16], p.sequence_number)
}
func (p *PDU_HEADER) Decode(data []uint8) {
	p.command_length = binary.BigEndian.Uint32(data[0:4])
	p.command_id = binary.BigEndian.Uint32(data[4:8])
	p.command_status = binary.BigEndian.Uint32(data[8:12])
	p.sequence_number = binary.BigEndian.Uint32(data[12:16])
}