package pnyx

import (
  "encoding/binary"
  "fmt"
)

type Packet struct {
  Channel ChannelID
  Mode ModeID
  Command byte
  Data []byte
}

func(packet Packet) String() string {
  return fmt.Sprintf("{Channel: %x, Mode: %x, Data: %x}", packet.Channel, packet.Mode, packet.Data)
}

func(packet Packet) MarshalBinary() ([]byte, error) {
  p := binary.BigEndian.AppendUint32(nil, uint32(packet.Channel))
  p = append(p, byte(packet.Mode))
  p = append(p, byte(packet.Command))
  return append(p, packet.Data...), nil 
}

func ParsePacket(data []byte) (*Packet, error) {
  if len(data) < 6 {
    return nil, fmt.Errorf("Not enough bytes to parse Packet(%d/%d)", len(data), 6)
  }

  return &Packet{
    Channel: ChannelID(binary.BigEndian.Uint32(data)),
    Mode: ModeID(data[4]),
    Command: data[5],
    Data: data[6:],
  }, nil
}