/*
sysex = f0 7f 70 02 01 01 31 2e 30 30 30 f7
univeral sysex = 127
device id = 112
msc = 2
command format = 1
command = 1
fader = 49
fader page = 46
fine value = 48
coarse value = 48

sysex = f0 7f 70 02 01 0a 30 2e 30 30 30 f7
univeral sysex = 127
device id = 112
msc = 2
command format = 1
command = 10
fader = 48
fader page = 46
fine value = 48
coarse value = 48

f0 7f usiversal sysex
70 device id
02 msc
01 command format (01 = general lighting)
0a command
30 2e 30 30 30 data
f7 end

=========== go 2.0 exec 2.1 ===========
0 f0 (240)
1 7f (127) universal sysex
2 7f (127) device id
3 02 (2) msc
4 01 (1) command format
5 01 (1) command
6 32 (50) ascii 2
7 2e (46) ascii .
8 30 (48) ascii 0
9 30 (48) ascii 0
10 30 (48) ascii 0
11 00 (0) ascii null
12 32 (50) ascii 2
13 2e (46) ascii .
14 31 (49) ascii 1
15 f7 (247)

=========== go 1.0 exec 2.1 ===========
0 f0 (240)
1 7f (127) universal sysex
2 7f (127) device id
3 02 (2) msc
4 01 (1) command format
5 01 (1) command (1 = goto)
6 31 (49) ascii 1
7 2e (46) ascii .
8 30 (48) ascii 0
9 30 (48) ascii 0
10 30 (48) ascii 0
11 00 (0) ascii null
12 32 (50) ascii 2
13 2e (46) ascii .
14 31 (49) ascii 1
15 f7 (247)

=========== goto 1.0 exec 2.1 ===========
0 f0 (240)
1 7f (127) universal sysex
2 7f (127) device id
3 02 (2) msc
4 01 (1) command format
5 01 (1) command (1 = goto)
6 31 (49) ascii 1
7 2e (46) .
8 30 (48) ascii 0
9 30 (48) ascii 0
10 30 (48) ascii 0
11 00 (0) ascii null
12 32 (50) ascii 2
13 2e (46) .
14 31 (49) ascii 1
15 f7 (247)

=========== off exec 2.1 ==============
0 f0 (240)
1 7f (127) universal sysex
2 7f (127) device id (127)
3 02 (2) msc
4 01 (1) command format (01 = general lighting)
5 0a (10) command (10)
6 30 (48) ascii 0
7 2e (46) .
8 30 (48) ascii 0
9 30 (48) ascii 0
10 30 (48) ascii 0
11 00 (0) ascii null
12 32 (50) ascii 2
13 2e (46) .
14 31 (49) ascii 1
15 f7 (247)

========= fader move ===============
0 f0
1 7f universal sysex
2 70 device id
3 02 msc
4 01 command format (01 = general lighting)
5 06 command (06 = set)
6 00 fader 1
7 01 page 1
8 7f 127 fine
9 7f 127 coarse
10 f7

fader value :
fader @45% =
45 * 1.28 = 57.6
coarse = 57
06 * 128 = 76.8
fine = 76
inverse =
Math.floor((new_fine_value + coarse_value) / 1.28)

osc address : /sysex
osc target : midi:gma_in
*/

INPUT_MIDI_DEVICE_NAME = 'gma_out';
OUTPUT_MIDI_DEVICE_NAME = 'gma_in';
DEBUG = true;

function faderToHex(fader_value) {
  var temp_coarse = fader_value * 1.28;
  var coarse = Math.floor(temp_coarse);
  var coarse_hex = coarse.toString(16);
  if (coarse < 16) coarse_hex = "0"+ coarse_hex;

  var coarse_decimals = (temp_coarse %1).toFixed(2);
  var temp_fine = coarse_decimals * 128;
  var fine = Math.floor(temp_fine);
  var fine_hex = fine.toString(16);
  if (fine < 16) fine_hex = "0"+ fine_hex;

  return {
    'coarse': coarse_hex,
    'fine': fine_hex
  }
}

function hexToFader(coarse, fine) {
  return Math.floor(((fine / 128) + coarse) / 1.28);
}

function moveOSCFader(host, port, address, args) {
  if (!(host === 'midi' && address === '/sysex' && port === INPUT_MIDI_DEVICE_NAME)) return;

  // hexadecimal string value
  
  var sysex_string = args[0].value
  if (DEBUG) console.log("sysex = " + sysex_string);

  // convert string to array of integers
  var ints = sysex_string.split(" ").map(x=>parseInt(x, 16))

  // parse items
  var [
    sysex_start,
    universal_sysex,
    device_id,
    msc,
    command_format,
    command,
    fader,
    fader_page,
    fine_value,
    coarse_value,
    sysex_end
  ] = ints;

  // if command = set
  if (command == 6) {
    var fader_percent = hexToFader(coarse_value, fine_value);
    if (DEBUG) console.log("fader percent = "+ fader_percent);
    receive("/fader_"+fader,fader_percent);
  }
  return true;
}

function moveMaFader(host, port, address, args) {
  if (host !== 'midi' || port !== OUTPUT_MIDI_DEVICE_NAME) return
  var fader_id = parseInt(address.substr(7)),
      fader_value = Math.ceil(args[0].value),
      outArgs = [];

  var fader_id_hex = fader_id.toString(16);
  if (fader_id < 16) fader_id_hex = "0"+ fader_id_hex;

  var hex_values = faderToHex(fader_value);
  var sysex = 'f0 7f 70 02 01 06 '+ fader_id_hex+ ' 01 '+ hex_values.fine+ ' '+ hex_values.coarse+ ' f7';

  send('midi', OUTPUT_MIDI_DEVICE_NAME, '/sysex', sysex);
  return true;
}

module.exports = {
    
  oscInFilter: (data)=>{
    if (DEBUG) console.log("in data : "+ JSON.stringify(data, null, 2));
    var {host, port, address, args} = data;
    if (moveOSCFader(host, port, address, args)) return;
    return data
  },

  oscOutFilter: (data)=>{
    var {host, port, address, args} = data;
    if (moveMaFader(host, port, address, args)) return;
    return data;
  }
  
}