import formatHex from '~/format-hex';
import { addAlpha, extractAlphaFromHex } from '~/modules/alpha';
import { MESSAGES } from '~/modules/constants';
import { invariant } from '~/modules/invariant';
import { isHex } from '~/modules/validators';

import { RGB } from '~/types';

/**
 * Convert HEX to RGB.
 *
 * @param input - The hex color string.
 * @returns The RGB color object.
 */
export default function hex2rgb(input: string): RGB {
  invariant(isHex(input), MESSAGES.inputHex);

  const hex = formatHex(input).slice(1);
  const alpha = extractAlphaFromHex(input);

  return addAlpha(
    {
      r: parseInt(hex.charAt(0) + hex.charAt(1), 16),
      g: parseInt(hex.charAt(2) + hex.charAt(3), 16),
      b: parseInt(hex.charAt(4) + hex.charAt(5), 16),
    },
    alpha,
  );
}