import { GumHexToRgb } from '../models';

/**
 * Removes hash from hex value
 * @param hex HEX color value
 */
const removeHash = (hex: string) => {
  const arr = hex.split('');
  arr.shift();
  return arr.join('');
};

/**
 * Expands shorthand HEX value (#FFF -> #FFFFFF)
 * @param hex HEX color value
 */
const expand = (hex: string) =>
  hex
    .split('')
    .reduce(
      (accum: string[], value: string) => accum.concat([value, value]),
      [],
    )
    .join('');
/**
 * Converts HEX color value to RGB
 * @param hex HEX color value
 */
export const hexToRgb: GumHexToRgb = (hex) => {
  if (hex.charAt && hex.charAt(0) === '#') {
    hex = removeHash(hex);
  }

  if (hex.length === 3) {
    hex = expand(hex);
  }

  const bigint = parseInt(hex, 16);
  const r = (bigint >> 16) & 255;
  const g = (bigint >> 8) & 255;
  const b = bigint & 255;

  return [r, g, b] as [number, number, number];
};