export function opacify(amount: number, hexColor: string): string {
  if (!hexColor.startsWith('#')) {
    return hexColor
  }

  if (hexColor.length !== 7) {
    throw new Error(
      `opacify: provided color ${hexColor} was not in hexadecimal format (e.g. #000000)`
    )
  }

  if (amount < 0 || amount > 100) {
    throw new Error('opacify: provided amount should be between 0 and 100')
  }

  const opacityHex = Math.round((amount / 100) * 255).toString(16)
  const opacifySuffix = opacityHex.length < 2 ? `0${opacityHex}` : opacityHex

  return `${hexColor.slice(0, 7)}${opacifySuffix}`
}
