@init

//* MATH *//

function round(num) local (int)
(
  int = floor(num);
  num - int < 0.5 ? floor(num) : ceil(num);
);

function coinToss()
(
  rand() < 0.5;
);

function randInt(num)
(
  round(rand() * num);
);

function clamp(num, min, max)
(
  max(min(num, max), min);
);

function isWithin(lo, hi, num)
(
  num >= lo && num <= hi;
);

function phase(elapsed, period) local(quotient, return) // phase(12, 8) = .5
(
  return = 0;
  period &&
  (
    elapsed < period ?
      (
        return = elapsed / period;
      ) :
      (
        quotient = elapsed / period;
        // decimal = quotient - quotient<<0
        return = (quotient - quotient<<0);
      );
  );
  return;
);

function mask(n)
(
  pow(2, n)-1;
);

// foo.readBits(6, 3) will read bits 7 thru 9 as if they were their own 3-bit integer
function readBits(offset, nBits)
(
  // foo = 1101111111
  // shifted right 6 bits = 1101
  // 1101 masked by 111 = 0101 = 5
  (this >> offset) & mask(nBits);
);

// foo.writeBits(6, 3, 2) will write the number 2 into bits 7 thru 9
// (num must fit in numBits else good luck using this as intended)
function writeBits(offset, nBits, num)
(
  // subtract whatever value is in those bits
  // 1XXX111111 -= (XXX << 6) = 1000111111
  this -= this.readBits(offset, nBits) << offset;
  // add num back into that n bit hole
  // 1000111111 + (2 << 6) = 1010111111
  this += num << offset;
  // -> foo.readBits(3, 6) = 010 = 2
);


// * ARRAYS *//

__nextArrayIdx = 0;

// tenSizeArray.arrayInit(10);
function arrayInit(size) local(index)
(
  this = __nextArrayIdx;
  __nextArrayIdx += size; // set up index for next call
  this.size = size;
  this.length = 0;
);

// tenSizeArray.default(-1)
function default(def) local(i)
(
  i = 0;
  while(i < this.size)
  (
    this[i] = def;
    i+= 1;
  );
  this.length = 0;
);

// tenSizeArray.push(foo)
function push(value)
(
  this.length < this.size && (
    this[this.length] = value;
    this.length += 1;
  );
);

// tenSizeArray.pop()
function pop() local (return)
(
  this.length > 0 ? (
    this.length -=1;
    return = this[this.length];
  ) : (
    // 😒 no way to indicate array was empty, 0 seems like "least spurious" value to return here
    return = 0;
  );
  return;
);

function find(value) local(return, i)
(
  return = -1;
  i = 0;
  while ((return == -1) && (i < this.length))
  (
    value == this[i] && return = i;
    i += 1;
  );
  return; // will return -1 or the first index containing the value
);

function random() local(i)
(
  i = randInt(this.length - 1);
  this[i];
);


//* MIDI *//

// wrap midirecv and interpret values
// usage: while(msg.recv()) (msg.send())
function recv() local(received)
(
  //capture return value of midirecv and scope its args
  received = midirecv(m0, m1, m2, m3);
  received &&
  (
    this.offset = m0;
    // m1 = status byte, some 8 bit number;
    // shift away lowest 4 bits: 1111???? -> 1111
    this.statusHi = m1 >> 4;
    // mask top 4 bits: ????1010 & 00001111 -> 00001010
    this.statusLo = m1 & $~4;
    this.data1 = m2;
    this.data2 = m3;
  );
  // return 1 or 0 for while() evaluation;
  received;
);


function send()
(
  midisend(
    this.offset,
    // reconstruct status by shifting high bits to the left
    // 1111 -> 11110000
    ((this.statusHi << 4) + this.statusLo),
    this.data1,
    this.data2
  );
);

function sendWithOffset(offset)
(
  midisend(
    offset,
    ((this.statusHi << 4) + this.statusLo),
    this.data1,
    this.data2
  )
);

function isNoteOn()
(
  this.statusHi == 9 && this.data2;
);


function isNoteOff()
(
  this.statusHi == 8 || (!this.data2 && this.statusHi == 9);
);

function isNote()
(
  this.isNoteOn() || this.isNoteOff();
);


function note()
(
  this.data1;
);

function channel()
(
  this.statusLo;
);


function isCC()
(
  this.statusHi == 11;
);

function isPitchBend()
(
  this.statusHi == 14;
);

// usage: msg.recv(),
// x = msg.toBits() -> now x is a number you can store in an array or whatever
function toBits()
(
  this.statusHi << 18 +
  this.statusLo << 14 +
  this.data1 << 7 +
  this.data2;
);
// x.parseBits() -> x is still a number but now has msg properties as well
// x.send();
function parseBits()
(
  this.statusHi = this.readBits(18, 4);
  this.statusLo = this.readBits(14, 4);
  this.data1 = this.readBits(7, 7);
  this.data2 = this.readBits(0, 7);
);
// ^^ nb. you can mutate x.foo then call x = x.toBits() again if need be

function sanitizeNoteOffs()
(
  this.statusHi == 9 && this.data2 == 0 && this.statusHi = 8;
);

function nrpn(offset, param, value)// local(status, paramMsb, valueMsb)
(
  status = 11<<4 + 1;
  paramMsb = param>>7;
  valueMsb = value>>7;
  midisend(offset, status, 99, paramMsb);
  midisend(offset, status, 98, param - paramMsb<<7);
  midisend(offset, status, 6, valueMsb);
  midisend(offset, status, 38, value - valueMsb<<7);
  midisend(offset, status, 101, 127);
  midisend(offset, status, 100, 127);

// 1011nnnn   01100011 ( 99)  0vvvvvvv         NRPN parameter number MSB CC
// 1011nnnn   01100010 ( 98)  0vvvvvvv         NRPN parameter number LSB CC
// 1011nnnn   00000110 (  6)  0vvvvvvv         NRPN parameter value MSB CC
// 1011nnnn   00100110 ( 38)  0vvvvvvv         NRPN parameter value LSB CC
// 1011nnnn   01100101 (101)  01111111 (127)   RPN parameter number Reset MSB CC
// 1011nnnn   01100100 (100)  01111111 (127)   RPN parameter number Reset LSB CC
);

function pitchBend(offset, channel, cents) local (cent, val, msb, lsb)
(
  cent = 2^14 / 2400;
  val = min((cents + 1200) * cent, $~14);
  msb = val>>7;
  lsb = val & $~7;
  midisend(offset, (14<<4 + channel), lsb, msb);
);

function allNotesOff() local(i)
(
  i = 0;
  while (i < 16)
  (
    midisend(0, (11<<4 + i), 123, 0);
    i += 1;
  );
);


//* STATE *//

_prevTempo = tempo;
_prevPlayState = play_state;

function playChanged() local(return)
(
  return = _prevPlayState !== play_state;
  return && _prevPlayState = play_state;
  return;
);

function tempoChanged() local(return)
(
  return = _prevTempo !== tempo;
  return && _prevTempo = tempo;
  return;
);


//* VALUES *//

function watch()
(
  this.prev = this;
  this.revert = this;
);

function changed()
(
  this !== this.prev &&
  (
    this.revert = this.prev;
    this.prev = this;
    1;
  );
);

function revert()
(
  this = this.revert;
  this.prev = this.revert;
);

function voidChange()
(
  this.prev = this;
);


//* CLOCK *//

function cInit()
(
  this.phase = 1; // ensure first tick
);

function tick() // call in @sample, will return 1 when phase rolls over
(
  this.phase < 1 ?
  (
    this.phase += this.sPhase;
    0;
  ) : (
    while (this.phase >= 1) (
      this.phase -= 1;
    );
    this.phase += this.sphase;
    1;
  );
);

function setPeriod(samples)
(
  this.sPhase = 1 / max(samples, 1); // disallow periods of less than 1 sample
  this.period = samples;
);

function setPeriodSeconds(seconds)
(
  this.setPeriod(seconds * srate); // 👀 may be non-integer
);

function setPeriodBars(bars) // 1/16, 1.5 etc
(
  // seconds per beat = 60 / tempo
  // seconds per bar = beats per measure * seconds per beat
  tempo && this.setPeriodSeconds(bars * ts_num * 60 / tempo);
);

function offset(phaseOffset)
(
  this.phase = phaseOffset - this.prevPhaseOffset;
  this.prevPhaseOffset = this.phase;
);