import { Pattern, clamp } from '@strudel/core';

import { getDrawContext, getTheme } from '@strudel/draw';

import { analysers, getAnalyzerData } from 'superdough';

/**

 * Renders a spectrum analyzer for the incoming audio signal.

 * @name spectrum

 * @param {object} config optional config with options:

 * @param {integer} thickness line thickness in px (default 3)

 * @param {integer} speed scroll speed (default 1)

 * @param {integer} min min db (default -80)

 * @param {integer} max max db (default 0)

 * @example

 * n("<0 4 <2 3> 1>*3")

 * .off(1/8, add(n(5)))

 * .off(1/5, add(n(7)))

 * .scale("d3:minor:pentatonic")

 * .s('sine')

 * .dec(.3).room(.5)

 * ._spectrum()

 */

let latestColor = {};

Pattern.prototype.spectrum = function (config = {}) {

  let id = config.id ?? 1;

  return this.analyze(id).draw(

    (haps) => {

      config.color = haps[0]?.value?.color || latestColor[id] || getTheme().foreground;

      latestColor[id] = config.color;

      drawSpectrum(analysers[id], config);

    },

    { id },

  );

};

Pattern.prototype.scope = Pattern.prototype.tscope;

const lastFrames = new Map();

function drawSpectrum(

  analyser,

  { thickness = 3, speed = 1, min = -80, max = 0, ctx = getDrawContext(), id = 1, color } = {},

) {

  ctx.lineWidth = thickness;

  ctx.strokeStyle = color;

  if (!analyser) {

    // if analyser is undefined, draw straight line

    // it may be undefined when no sound has been played yet

    return;

  }

  const scrollSize = speed;

  const dataArray = getAnalyzerData('frequency', id);

  const canvas = ctx.canvas;

  ctx.fillStyle = color;

  const bufferSize = analyser.frequencyBinCount;

  let imageData = lastFrames.get(id) || ctx.getImageData(0, 0, canvas.width, canvas.height);

  lastFrames.set(id, imageData);

  ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);

  ctx.putImageData(imageData, -scrollSize, 0);

  let q = canvas.width - speed;

  for (let i = 0; i < bufferSize; i++) {

    const normalized = clamp((dataArray[i] - min) / (max - min), 0, 1);

    ctx.globalAlpha = normalized;

    const next = (Math.log(i + 1) / Math.log(bufferSize)) * canvas.height;

    const size = 2; //next - pos;

    ctx.fillRect(q, canvas.height - next, scrollSize, size);

  }

  lastFrames.set(id, ctx.getImageData(0, 0, canvas.width, canvas.height));

}