teableio/teable

/* eslint-disable @typescript-eslint/naming-convention */
const COLORS_NB: number = 9;
const DEFAULT_SATURATION: number = 95;
const DEFAULT_LIGHTNESS: number = 45;

const MAGIC_NUMBER: number = 5;

function simpleHash(str: string): number {
  return (
    str
      .split('')
      .reduce((hash, char) => (hash ^ char.charCodeAt(0)) * -MAGIC_NUMBER, MAGIC_NUMBER) >>> 2
  );
}

interface MinidenticonFunction {
  (
    seed?: string,
    saturation?: number,
    lightness?: number,
    hashFn?: (str: string) => number
  ): string;
}

const minidenticon: MinidenticonFunction = function (
  seed: string = '',
  saturation: number = DEFAULT_SATURATION,
  lightness: number = DEFAULT_LIGHTNESS,
  hashFn: (str: string) => number = simpleHash
): string {
  const hash = hashFn(seed);
  const hue = (hash % COLORS_NB) * (360 / COLORS_NB);
  return (
    [...Array(seed ? 25 : 0)].reduce(
      (acc, _, i) =>
        hash & (1 << i % 15)
          ? acc +
            `<rect x="${i > 14 ? 7 - ~~(i / 5) : ~~(i / 5)}" y="${i % 5}" width="1" height="1"/>`
          : acc,
      `<svg viewBox="-1.5 -1.5 8 8" xmlns="http://www.w3.org/2000/svg" fill="hsl(${hue} ${saturation}% ${lightness}%)">`
    ) + '</svg>'
  );
};

export { minidenticon };