export function hexToRgb(hex: string) {
  const shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  const hexTmp = hex.replace(shorthandRegex, (m, r, g, b) => (
    r + r + g + g + b + b
  ));

  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hexTmp);
  return result ? {
    r: parseInt(result[1], 16),
    g: parseInt(result[2], 16),
    b: parseInt(result[3], 16),
  } : null;
}

export const getOpaqueHexColor = (hex: string, opacity: number) => {
  const rgb = hexToRgb(hex);
  if (!rgb) return hex;

  return `rgba(${rgb.r}, ${rgb.g}, ${rgb.b}, ${opacity})`;
};

export function luminance(r: number, g: number, b: number) {
  const a = [r, g, b].map((v) => {
    const tmp = v / 255;
    return tmp <= 0.03928
      ? v / 12.92
      : ((v + 0.055) / 1.055) ** 2.4;
  });
  return a[0] * 0.2126 + a[1] * 0.7152 + a[2] * 0.0722;
}

export function contrast(luminance1: number, luminance2: number) {
  return luminance1 > luminance2
    ? ((luminance2 + 0.05) / (luminance1 + 0.05))
    : ((luminance1 + 0.05) / (luminance2 + 0.05));
}