import Tone from 'tone'

import output from './output'

const signalWindows = require('signal-windows').windows
const FFTJS = require('fft.js')

const fft_size = 2 << 10
const fft_overlap = fft_size / 4
const half_fft_size = fft_size / 2

const fft = new FFTJS(fft_size)

function toSpectrum(pcm, sr){
  sr = sr || 44100
  const ham = signalWindows.construct('ham', fft_size)
  const pcm_in = new Array(fft_size)
  const pcm_length = pcm.length
  const pcm_q_length = Math.ceil(pcm_length / fft_size) * fft_size
  let i, j, fft_out, data = [];
  for (i = -fft_size; i < pcm_q_length; i += fft_overlap) {
    for (j = 0; j < fft_size; j++) {
      pcm_in[j] = pcm[i+j] * ham[j] || 0
    }
    fft_out = fft.createComplexArray()
    fft.realTransform(fft_out, pcm_in)
    fft.completeSpectrum(fft_out)
    data.push(fft_out)
  }
  return {
    data,
    sr,
    fft_size,
    fft_overlap,
  }
}

function fromSpectrum(spec){
  const data = spec.data
  const sr = spec.sr
  const fft_size = spec.fft_size
  const fft_overlap = spec.fft_overlap
  const spec_len = data.length

  const ham = signalWindows.construct('ham', fft_size)
  const out = fft.createComplexArray()
  const pcm_length = fft_overlap * spec_len

  const audioBuffer = Tone.context.createBuffer(1, pcm_length, sr)
  const pcm = audioBuffer.getChannelData(0);

  let i, j, u, v, _r, _i, col

  for (i = 0; i < spec_len; i++) {
    col = data[i]
    fft.inverseTransform(out, col)
    u = i * (fft_overlap)
    // for (j = fft_size * 1/4; j < fft_size * 3/4; j++) {
    //   pcm[u+j] = out[j*2] / ham[j] || 0
    // }
    for (j = 0; j < fft_size; j++) {
      pcm[u+j] += out[j*2] * ham[j] || 0
    }
  }

  fadeInOut(pcm, fft_size)

  return audioBuffer
}

function fadeInOut(pcm, fade_size){
  const pcm_length = pcm.length
  let fade = 0, i
  for (i = 0; i < fade_size; i++) {
    fade = i / (fade_size)
    fade *= fade
    pcm[i] *= fade
    pcm[pcm_length - i] *= fade
  }
}
function fadeOut(pcm){
  
}

export default {
  toSpectrum,
  fromSpectrum
}