/** The Bitcrusher's samples (#322), as its worklet makes them. */
import { describe, expect, it } from 'vitest';
import { Crusher, crushSteps } from '../../src/core/soundfx/crusher';

const RATE = 48000;
const one = (value: number) => new Float32Array([value]);

function crush(input: number[], bits: number | number[], rate: number, mix = 1, crusher = new Crusher(RATE)) {
  const out = new Float32Array(input.length);
  const bitsAt = typeof bits === 'number' ? one(bits) : new Float32Array(bits);
  crusher.render([new Float32Array(input)], [out], bitsAt, one(rate), one(mix));
  return [...out];
}

describe('the Bitcrusher (#322)', () => {
  it('rounds to 2^(bits-1) steps either side of 0, between whole bits too', () => {
    expect(crush([0.3, 0.6, -0.4, -0.8, 1], 1, RATE)).toEqual([0, 1, 0, -1, 1]);
    expect(crush([0.3, 0.6, -0.4], 2, RATE)).toEqual([0.5, 0.5, -0.5]);
    expect(crushSteps(3.5)).toBeCloseTo(2 ** 2.5);
    expect(crushSteps(16)).toBe(32768);
    expect([crushSteps(0), crushSteps(99), crushSteps(Number.NaN)]).toEqual([1, 32768, 32768]);
  });

  it('holds a sample for as long as its rate says', () => {
    expect(crush([0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8], 16, RATE / 4).map((v) => +v.toFixed(3))).toEqual([
      0.1, 0.1, 0.1, 0.1, 0.5, 0.5, 0.5, 0.5,
    ]);
    // A third of the rate: every third sample, wherever it falls.
    expect(
      crush(
        [1, 2, 3, 4, 5, 6, 7].map((v) => v / 10),
        16,
        RATE / 3,
      ).map((v) => +v.toFixed(3)),
    ).toEqual([0.1, 0.1, 0.1, 0.4, 0.4, 0.4, 0.7]);
  });

  it('blends with the sound by its mix, and bits can change from sample to sample', () => {
    expect(crush([0.3], 1, RATE, 0)).toEqual([expect.closeTo(0.3)]);
    expect(crush([0.3], 1, RATE, 0.5)).toEqual([expect.closeTo(0.15)]);
    expect(crush([0.3, 0.3], [1, 2], RATE)).toEqual([0, 0.5]);
  });

  it('lets go of what it holds once nothing comes in, so no DC is left', () => {
    const crusher = new Crusher(RATE);
    crush([0.9, 0.9], 16, 100, 1, crusher);
    const out = new Float32Array(4).fill(7);
    crusher.render([], [out], one(16), one(100), one(1));
    expect([...out]).toEqual([0, 0, 0, 0]);
    expect(crush([0.25], 16, 100, 1, crusher)).toEqual([0.25]);
  });
});