/*
    iPod Serial Decoder
    
    Smarts by:
    Scott Lawrence
    yorgle@gmail.com
    http://umlautllama.com
    
    Bastard Hackery by:
    Steve Vigneau
    c0nsumer@nuxx.net
    http://www.nuxx.net 
*/

import processing.serial.*;

Serial rxPort;
Serial txPort;

int baudRate = 9600;  /* 9600 for Honda Music Link */

void setup()
{
  size( 200, 200 );

  
  println( "Available serial ports: (pick one of these for serialPort)" );
  println( Serial.list() );

  // rxPort is the serial port connected to the RX line of the HML
  // txPort is connected to the TX line of the HML
  this.txPort = new Serial( this, "COM1", baudRate );
  this.rxPort = new Serial( this, "COM15", baudRate );
}

void draw()
{
  pollTXSerial();
  pollRXSerial();
}

static final int RX_STATE_NONE       = 0;
static final int RX_STATE_A_FF       = 1;
static final int RX_STATE_B_55       = 2;
static final int RX_STATE_C_SIZE     = 3;
static final int RX_STATE_D_PACKET   = 4;
static final int RX_STATE_E_CHECKSUM = 5;

static final int TX_STATE_NONE       = 0;
static final int TX_STATE_A_FF       = 1;
static final int TX_STATE_B_55       = 2;
static final int TX_STATE_C_SIZE     = 3;
static final int TX_STATE_D_PACKET   = 4;
static final int TX_STATE_E_CHECKSUM = 5;

int rxCurrentState = RX_STATE_A_FF; /* this holds the current state; what we're looking for */
int rx_acc[]; /* accumulator */
int rx_ac;    /* position while reading strings */

int txCurrentState = TX_STATE_A_FF; /* this holds the current state; what we're looking for */
int tx_acc[]; /* accumulator */
int tx_ac;    /* position while reading strings */

void pollRXSerial()
{
  /* poll the serial port - read in data */
  while( this.rxPort.available() > 0) {
    int rxValue = this.rxPort.read();

    /* the state machine... */
    switch( rxCurrentState ) {
      case( RX_STATE_A_FF ):
        if( rxValue == 0xff ) {
          rxCurrentState = RX_STATE_A_FF;
        }
        break;
        
      case( RX_STATE_B_55 ):
        if( rxValue == 0x55 ) {
          rxCurrentState = RX_STATE_B_55;
        }
        break;
        
      case( RX_STATE_C_SIZE ):
        rx_acc = new int[ rxValue ]; /* allocate our buffer space for the message */
        rx_ac = 0;
        rxCurrentState = RX_STATE_D_PACKET;
        break;
        
      case( RX_STATE_D_PACKET ): /* read packet bytes until done */
        rx_acc[ rx_ac++ ] = rxValue;
        if( rx_ac >= (rx_acc.length-1)) {
          rxCurrentState = RX_STATE_E_CHECKSUM;
        }
        break;
        
      case( RX_STATE_E_CHECKSUM ):
        int rx_acc_csum = computeChecksum( rx_acc );
        if( rx_acc_csum != rxValue )
        {
          println( "RX: Received a packet, but the checksum didn't match! eep!" );
        }
        handleCommand( rx_acc );
        break;
    }

    /* print out the value received in hex and decimal*/
    /* do some extra work if the value is "0x03", since java wants to display that as "0x3" */
    String hexVersion = "0x";
    if( Integer.toHexString( rxValue ).length() == 1 ) {
      hexVersion += "0"; /* 0-pad single digits for readability */
    }
    hexVersion += Integer.toHexString( rxValue );
    println( "RX: " + hexVersion + "  " );
  }
}

void pollTXSerial()
{
  /* poll the serial port - read in data */
  while( this.txPort.available() > 0) {
    int txValue = this.txPort.read();

    /* the state machine... */
    switch( txCurrentState ) {
      case( TX_STATE_A_FF ):
        if( txValue == 0xff ) {
          txCurrentState = TX_STATE_A_FF;
        }
        break;
        
      case( TX_STATE_B_55 ):
        if( txValue == 0x55 ) {
          txCurrentState = TX_STATE_B_55;
        }
        break;
        
      case( TX_STATE_C_SIZE ):
        tx_acc = new int[ txValue ]; /* allocate our buffer space for the message */
        tx_ac = 0;
        txCurrentState = TX_STATE_D_PACKET;
        break;
        
      case( TX_STATE_D_PACKET ): /* read packet bytes until done */
        tx_acc[ tx_ac++ ] = txValue;
        if( tx_ac >= (tx_acc.length-1)) {
          txCurrentState = TX_STATE_E_CHECKSUM;
        }
        break;
        
      case( TX_STATE_E_CHECKSUM ):
        int tx_acc_csum = computeChecksum( tx_acc );
        if( tx_acc_csum != txValue )
        {
          println( "TX: Received a packet, but the checksum didn't match! eep!" );
        }
        handleCommand( tx_acc );
        break;
    }

    /* print out the value received in hex and decimal*/
    /* do some extra work if the value is "0x03", since java wants to display that as "0x3" */
    String hexVersion = "0x";
    if( Integer.toHexString( txValue ).length() == 1 ) {
      hexVersion += "0"; /* 0-pad single digits for readability */
    }
    hexVersion += Integer.toHexString( txValue );
    println( "TX: " + hexVersion + "  " );
  }
}

/* the passed around buf[] array is allocated as such:
   buf[0] = length (mode + command + parameter)
   buf[1] = mode command
   buf[2] = byte 1 of command
   buf[3] = byte 2 of command
   buf[4...] = parameters
*/

int computeChecksum( int buf[] )
{
  int csum = 0;
  for( int i=0 ; i< buf.length ; i++ )
  {
    csum += (buf[i] & 0x00ff);
  }
  csum &= 0x00ff;
  return 0x0100 - csum;
}

void handleCommand( int packet[] )
{
  if( packet == null || packet.length < 7 ) {
    println( "bad command" );
    return;
  }
  switch( packet[1] ) /* mode */
  {
    case( 0x00 ):  /* mode switching */
      if( packet[2] == 0x01 ) {
        switch( packet[3] )
          {
            case( 0x01 ): println( "Switch to Voice Memo Mode (Mode 1)" ); break;
            case( 0x02 ): println( "Switch to iPod Remote Mode (Mode 2)"); break;
            case( 0x04 ): println( "Switch to AiR Mode (Mode 4)"); break;
          }
      }
      if( packet[2] == 0x03 ) {
        println( "Get Current Mode Status" ); break;
      }
      if( packet[2] == 0x04 ) {
        println( "Mode Status Response" ); break;
      }
      if( packet[2] == 0x05 ) {
        println( "Switch to AiR Mode (Mode 4)"); break;
      }
      if( packet [2] == 0x06 ) {
        println( "Switch to iPod Remote Mode (Mode 2)"); break;
      }
      break;
      
    case( 0x01 ):  /* voice recorder */
      if( packet[2] == 0x01 ) {
        if( packet[3] == 0x00 ) {
          println( "Recording has started" ); break;
        }
        if( packet[3] == 0x01 ) {
          println( "Recording has stopped or paused" ); break;
        }
      }
      break;
      
    case( 0x02 ):  /* simple remote */
      /* since these are mostly 0x00-packed, we can cheat a little... */
      if( packet.length == 4 ) /* two-byte command */
      {
        /* packet[0] should be the same as packet.length (4)*/
        /* packet[1] should contain the mode (0x02) */
        /* packet[2] should be 0x00 here */
        /* packet[3] should be the command to look at */
        switch( packet[3] )
        {
          case( 0x00 ):  println( "Button Released" ); break;
          case( 0x01 ):  println( "Play/Pause" ); break;
          case( 0x02 ):  println( "Vol +" ); break;
          case( 0x04 ):  println( "Vol -" ); break;
          case( 0x08 ):  println( "Skip >" ); break;
          case( 0x10 ):  println( "Skip <" ); break;
          case( 0x20 ):  println( "Next Album" ); break;
          case( 0x40 ):  println( "Previous Album" ); break;
          case( 0x80 ):  println( "Stop" ); break;
        }
      }
      if( packet.length == 5 ) /* three-byte command */
      {
        /* as above, but: */
        /* packet[2]  0x00 */
        /* packet[3]  0x00 */
        /* packet[4]  command */
        switch( packet[4] ) /* just look at the last byte of the command */
        {
          case( 0x01 ):  println( "Play (Just Pause, No Flip Play Mode)" ); break;
          case( 0x02 ):  println( "Pause (Just Pause, No Flip Play Mode)" ); break;
          case( 0x04 ):  println( "Mute Toggle" ); break;
          case( 0x20 ):  println( "Next Playlist" ); break;
          case( 0x40 ):  println( "Previous Playlist" ); break;
          case( 0x80 ):  println( "Shuffle Toggle" ); break;
        }
      }
      if( packet.length == 6 ) /* four-byte command */
      {
        switch( packet[5] ) /* just look at the last byte of the command */
        {
          case( 0x01 ):  println( "Toggle Repeat" ); break;
          case( 0x04 ):  println( "iPod Off" ); break;
          case( 0x08 ):  println( "iPod On" ); break;
          case( 0x40 ):  println( "Menu Button" ); break;
          case( 0x80 ):  println( "OK/Select" ); break;
        }
      }
      if( packet.length == 7 ) /* five-byte command */
      {
        switch( packet[6] ) /* just look at the last byte of the command */
        {
          case( 0x01 ):  println( "Scroll Up" ); break;
          case( 0x02 ):  println( "Scroll Down" ); break;
        }
      }
      break;
      
    case( 0x03 ):  /* request mode status */
      break;
      
    case( 0x04 ):  /* AiR Mode */
      switch( packet[3] ) /* seems to only be a set length used for the commands in AiR */
      {
        case( 0x00 ): println( "Unknown 0x00 0x00" ); break;
        case( 0x01 ): println( "Command Feedback: " + packet[4] + " " + packet[5] ); break;
        case( 0x02 ): println( "Ping Request? (Uncertain) " ); break;
        case( 0x03 ): println( "Ping Reply? (Uncertain) " ); break;
        case( 0x09 ): println( "Unknown 0x00 0x09" ); break;
        case( 0x0a ): println( "Unknown 0x00 0x0a: " + packet[4] ); break;
        case( 0x0b ): println( "Unknown 0x00 0x0b: " + packet[4] ); break;
        case( 0x0c ): println( "Unknown 0x00 0x0c" ); break;
        case( 0x0d ): println( "Unknown 0x00 0x0d" ); break;
        case( 0x12 ): println( "Get iPod Type / Size (Uncertain)" ); break;
        case( 0x13 ): println( "iPod Type Reply: " + packet[4] ); break;
        case( 0x14 ): println( "Get iPod Name" ); break;
        case( 0x15 ): println( "iPod Name Reply" ); break;
        case( 0x16 ): println( "Switch to Main Library Playlist" ); break;
        case( 0x17 ): println( "Switch to Item Defined By Number and Type: " + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] + " " + packet[8] ); break;
        case( 0x18 ): println( "Get Count of Type: " + packet[4] ); break;
        case( 0x19 ): println( "Count of Type Reply: " + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] ); break;
        case( 0x1a ): println( "Get Names for Range of Items" ); break;
        case( 0x1b ): println( "Name of Range of Items Reply" ); break;
        case( 0x1c ): println( "Get Time and Status" ); break;
        case( 0x1d ): println( "Time and Status Reply: " + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] + " " + packet[8] + " " + packet[9] + " " + packet[10] + " " + packet[11] + " " + packet[12] ); break;
        case( 0x1e ): println( "Get Current Position in Playlist" ); break;
        case( 0x1f ): println( "Current Position in Playlist: " + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] ); break;
        case( 0x20 ): println( "Get Title of Song Number" ); break;
        case( 0x21 ): println( "Title Return as Null Terminated String" ); break;
        case( 0x22 ): println( "Get Artist of Song Number" ); break;
        case( 0x23 ): println( "Artist Return as Null Terminated String" ); break;
        case( 0x24 ): println( "Get Album of Song Number" ); break;
        case( 0x25 ): println( "Album Return as Null Terminated String" ); break;
        case( 0x26 ): println( "Enable Polling Mode: " + packet[4] ); break;
        case( 0x27 ): println( "Polling Mode Reply (Elapsed Time on Current Song): " + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] ); break;
        case( 0x28 ): println( "Execute Playlist switch specified in command 0x00 0x17, and jump to specified songnumber in the playlist." ); break;
        case( 0x29 ): /* AiR Playback Control */
          switch( packet[4] )
          {
            case( 0x01 ): println( "AiR Playback Control: Play/Pause" ); break;
            case( 0x02 ): println( "AiR Playback Control: Stop" ); break;
            case( 0x03 ): println( "AiR Playback Control: Skip++" ); break;
            case( 0x04 ): println( "AiR Playback Control: Skip--" ); break;
            case( 0x05 ): println( "AiR Playback Control: FFwd" ); break;
            case( 0x06 ): println( "AiR Playback Control: FRwd" ); break;
            case( 0x07 ): println( "AiR Playback Control: StopFF/RW" ); break;
          }
        break;
        case( 0x2c ): println( "Get Shuffle Mode" ); break;
        case( 0x2d ): /* Shuffle Mode Replies */
          switch( packet[4] )
          {
            case( 0x00 ): println( "Shuffle Mode Is: Off" ); break;
            case( 0x01 ): println( "Shuffle Mode Is: Songs" ); break;
            case( 0x02 ): println( "Shuffle Mode Is: Albums" ); break;
          }
        break;
        case( 0x2e ): /* Set Shuffle Mode */
          switch( packet[4] )
          {
            case( 0x00 ): println( "Set Shuffle Mode: Off" ); break;
            case( 0x01 ): println( "Set Shuffle Mode: Songs" ); break;
            case( 0x02 ): println( "Set Shuffle Mode: Albums" ); break;
          }
        break;
        case( 0x2f ): println( "Get Repeat Mode" ); break;
        case( 0x30 ): /* Repeat Mode Replies */
          switch( packet[4] )
          {
            case( 0x00 ): println( "Repeat Mode Is: Off" ); break;
            case( 0x01 ): println( "Repeat Mode Is: One Song" ); break;
            case( 0x02 ): println( "Repeat Mode Is: All Songs" ); break;
          }
        break;
        case( 0x31 ): /* Set Repeat Mode */
          switch( packet[4] )
          {
            case( 0x00 ): println( "Set Repeat Mode: Off" ); break;
            case( 0x01 ): println( "Set Repeat Mode: One Song" ); break;
            case( 0x02 ): println( "Set Repeat Mode: All Songs" ); break;
          }
        break;
        case( 0x32 ): println( "Upload AiR Mode Picture" ); break;
        case( 0x33 ): println( "Get Max Screen Size For Picture (Uncertain)" ); break;
        case( 0x34 ): println( "Resolution for Picture (Uncertain)" ); break;
        case( 0x35 ): println( "Get Number of Songs In Current Playlist" ); break;
        case( 0x36 ): println( "Number of Songs in Current Playlist: " + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] ); break;
        case( 0x37 ): println( "Jump to Specified Song in Current Playlist"  + packet[4] + " " + packet[5] + " " + packet[6] + " " + packet[7] ); break;
        case( 0x38 ): println( "Unknown" ); break;
        case( 0x39 ): println( "Unknown (Perhaps colordepth?)" ); break;
      }
      break;
  }
}

/*  I don't think we need this for now...
void keyPressed() {
  exit();
} */