sequencer.js

'use strict';
var midiConnector = require('midi-launchpad').connect(1) // change this to your midi port n

var file = require('fs')
var midi = require('midi')
var output = new midi.output()
output.getPortCount()
output.getPortName(0)
output.openVirtualPort('Path Sequencer') // this is only for linux & mac

// on app close
// output.closePort();


var lp = null;
var Seq = null;
var btnconf = null;

var time = function()
{
   return new Date().getTime()
}

// todo add the colors to the btnconf.json as well
var loadButtonConfig = function()
{
   try   {
      var conf = file.readFileSync('btnconf.json').toString();
      btnconf = JSON.parse(conf)
   } catch(e)
   {
      // file not present or bad format, exit
      console.log('configuration file btnconf.json file is missing or is badly formatted, exiting')
      console.log(e)
      process.exit(1)
   }
}


// main app call
var main = function(launchpad)
{
   loadButtonConfig()
   lp = launchpad
   Seq = new Sequencer();
   Seq.main()
}


// one Sequencer
// the Sequencer hasMany Sequences
// Sequence hasMany Notes
// Notes have duration, end time and a Button
// Button has Functions
class Sequencer
{
   constructor()
   {
      this.sequences = []
      console.log(['this.sequences', this.sequences])
      this.recording = false
   }
   main()
   {
      // boot the buttons
      this.buttons = [];
      for (var i = 0; i < 9; i++) {
         for (var j = 0; j < 9; j++)   {
            var id = ('' + i + '' + j + '')
            this.buttons[id] = new Button(id, lp.getButton(i,j));
         }
      }
   }
   play(){}
   lastSequence()
   {
      return this.sequences[this.sequences.length-1]
   }
   playLastSequence()
   {
      this.lastSequence().play()
   }
   stop()
   {
      debug('stopping last sequence')
      this.lastSequence().stop = true
      this.sequences.pop()
      // console.log(this.lastSequence())
      // this.lastSequence().stop()
   }
   tapTempo(){}
   record()
   {
      this.sequences.push(new Sequence())
      if (!this.recording) {
         this.recording = true
      } else {
         this.recording = false
      }
   }
   press(btn)
   {
      if (!this.recording) {
         return
      }

      if (this.lastSequence().isFirstNote(btn)) {
         this.playLastSequence()
      }

      this.lastSequence().addBegin(btn)
   }
   release(btn)
   {
      if (!this.recording) {
         return
      }
      this.lastSequence().addEnd(btn)
   }
}

class Sequence
{
   constructor()
   {
      this.stop = false
      this.notes = []
      this.recordingNote = null
      this.currentNote = 0
   }
   addBegin(btn)
   {
      if (this.recordingNote !== null) {
         this.recordingNote.len = (time() - this.recordingNote.len);
         this.notes.push(this.recordingNote)
      }
      this.recordingNote = new Note(btn)
      this.recordingNote.len = this.recordingNote.stime = time()
   }
   addEnd(btn)
   {
      this.recordingNote.etime = (time() - this.recordingNote.stime)
   }
   isFirstNote(btn)
   {
      if (!this.notes.length) {
         return false
      }
      if (btn.id === this.notes[0].btn.id) {
         return true
      }
      return false
   }
   clear(){}
   mute(){}
   redouble(){}
   stop()
   {
      this.stop = true
   }
   play()
   {
      if (this.stop) {
         return
      }

      if (this.currentNote >= this.notes.length) {
         this.currentNote = 0
      }

      var curNote = this.notes[this.currentNote]
      var curButton = curNote.btn

      curButton.actionFromSeq(true)

      setTimeout(function(btn){
         btn.actionFromSeq(false)
      }, curNote.etime, curButton)

      setTimeout(function(parent){
         parent.play()
      }, curNote.len, this)

      this.currentNote++
   }
}

class Note
{
   constructor(btn)
   {
      this.btn = btn
      this.len = 0   // total note len
      this.stime = 0
      this.etime = 0 // pressed duration
   }
}

class Button
{
   constructor(id, btn)
   {
      // construct
      this.id = id

      this.specialColor = lp.colors.red.low

      this.specialColorOn = false

      var parent = this

      this.btn = btn

      this.btn.on('press', function(){
         parent.action(true);
      });

      this.btn.on('release', function(){
         parent.action(false);
      });

   }

   action(por)
   {

      if (!this.btn.special) {
         if (por) {
            this.btn.light(lp.colors.red.high)
         } else {
            this.btn.light(lp.colors.off)
         }
         return this.actionToNote(por, this.btn.toNote());
      }

      if (this.btn.special == 'up,page') {
         return this.actionRecord(por)
      }

      if (this.btn.special == 'down,page') {
         return this.actionPlay(por)
      }

      if (this.btn.special == 'left,page') {
         return this.actionStop(por)
      }
   }

   actionFromSeq(por)
   {
      if (por) {
         output.sendMessage([144, this.btn.toNote(), 127]);
         this.btn.light(lp.colors.red.high)
      } else {
         output.sendMessage([128, this.btn.toNote(), 40]);
         this.btn.light(lp.colors.off)
      }
      // console.log(this.btn.toNote())
   }

   actionToNote(por, note)
   {
      if (por) {
         Seq.press(this)
      } else {
         Seq.release(this)
      }
      //
      // todo send midi signal here
      // console.log(note)
   }

   actionPlay(por)
   {
      Seq.play(por)
   }

   actionStop(por)
   {
      Seq.stop(por)
   }

   actionRecord(por)
   {
      if (!por) {
         return; // this button ignores release
      }
      if (this.specialColorOn) {
         this.specialColorOn = false
         this.btn.light(lp.colors.off)
      } else {
         debug('recording')
         this.specialColorOn = true
         this.btn.light(this.specialColor)
      }
      Seq.record()
   }

}

midiConnector.on("ready", function(launchpad) {
   console.log("the hardware is ready")
   main(launchpad)
});

var debugLevel = 1
var debug = function(w)
{
   if (!debugLevel) {
      return
   }
   console.log(w)
}
var debugButton = function(btn)
{
   if (!debugLevel) {
      return
   }
   console.log(
      "Pressed: "+
      "x:"        +btn.x          +", "+
      "y:"        +btn.y          +", "+
      "state:"    +btn.getState() +", "+
      "special:"  +btn.special
   );
}

/*
   Pressed: x:0, y:0, state:1, special:false
   Released: x:0, y:0, state:0, special:false
   Pressed: x:7, y:7, state:1, special:false
   Pressed: x:7, y:7, state:0, special:false

   Pressed: x:0, y:8, state:1, special:up,page
   Pressed: x:1, y:8, state:1, special:down,page
   Pressed: x:2, y:8, state:1, special:left,page
   Pressed: x:3, y:8, state:1, special:right,page
   Pressed: x:4, y:8, state:1, special:session,inst
   Pressed: x:5, y:8, state:1, special:user 1,fx
   Pressed: x:6, y:8, state:1, special:user 2,user
   Pressed: x:7, y:8, state:1, special:mixer,mixer

   Pressed: x:8, y:0, state:1, special:right,vol
   Pressed: x:8, y:1, state:1, special:right,pan
   Pressed: x:8, y:2, state:1, special:right,snd A
   Pressed: x:8, y:3, state:1, special:right,snd B
   Pressed: x:8, y:4, state:1, special:right,stop
   Pressed: x:8, y:5, state:1, special:right,trk on
   Pressed: x:8, y:6, state:1, special:right,solo
   Pressed: x:8, y:7, state:1, special:right,arm
 */

/*

   basic layout per btnconf.json:
   8 sequences + {arm the sequence, deselect any sequence}
x  * * * * * * * *  y
   n 2 3 4 5 6 7 8  * {fn-play-stop: fn+x play/stop x}
   1 n 3 4 5 6 7 8  * {fn-mute: fn+x = mute sequence, fn+n = mute n }    // mute color yellow
   1 2 n 4 5 6 7 8  * {fn-clear: fn+x = clear sequence, fn+n = clear n}
   1 2 3 n 5 6 7 8  *
   1 2 3 4 n 6 7 8  *
   1 2 3 4 5 n 7 8  *
   1 2 3 4 5 6 n 8  * {fn-redoubles: fn+n = select, }
   1 2 3 4 5 6 7 n  * {tempo blink tappable}
 */