package pdu

type (
	PDU interface {
		Encode() []byte
		Decode([]byte)
	}

	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() []byte {
    // Encode PDU_HEADER fields to byte slice
    // (For simplicity, we assume little-endian encoding)
    buf := make([]byte, 16)
    encodeUint32(buf[0:4], p.command_length)
    encodeUint32(buf[4:8], p.command_id)
    encodeUint32(buf[8:12], p.command_status)
    encodeUint32(buf[12:16], p.sequence_number)
    return buf
}