let w, h, a, b, notes, assign
function init(z, fn){
  // really bad
  notes = z
  assign = fn
  build()
  setTempo(50)
}
function build(){
  w = notes.length
  h = notes[0].length
  a = a || new Array(w)
  b = b || new Array(w)
  for (var i = 0; i < w; i++) {
    a[i] = a[i] || new Array(h)
    b[i] = b[i] || new Array(h)
    for (var j = 0; j < h; j++) {
      a[i][j] = b[i][j] = (notes[i][j] && notes[i][j].playing) ? 1 : 0
    }
  }
}
let timeout, delay = 1200 // ~120 bpm
function toggle(){
  build()
  if (timeout) {
    clearTimeout(timeout)
    timeout = null
  }
  else {
    step()
  }
}
function assign_item(freq,state){
  b[freq.i][freq.j] = state ? 1 : 0
}
function setTempo(bpm){
  console.log('bpm:', bpm)
  delay = 60000/bpm
}
function swap () {
  var tmp = a
  a = b
  b = tmp
}
function step() {
  clearTimeout(timeout)
  timeout = setTimeout(step, delay)
  swap()
  let i, j, ni, pi, nj, pj, score, state
  for (i = 0; i < w; i++) {
    for (j = 0; j < h; j++) {
      ni = i === 0 ? w-1 : i-1
      pi = i === w-1 ? 0 : i+1
      nj = j === 0 ? h-1 : j-1
      pj = j === h-1 ? 0 : j+1
      score = a[ni][nj] + a[ni][j] + a[ni][pj] + a[i][nj] + a[i][pj] + a[pi][nj] + a[pi][j] + a[pi][pj]
      state = fitness(a[i][j], score)
      b[i][j] = state
      if (a[i][j] !== state) {
        assign(notes[i][j], state)
      }
    }
  }
}
function fitness (old, score) {
  if (old === 1) {
    if (score === 2 || score === 3) return 1
  } else {
    if (score === 3) return 1
  }
  return 0
}

export default { init, step, assign_item, toggle, setTempo }