function parseHex (hex: string) {
  let result = hex

  // remove hash symbol
  if (result.startsWith('#')) {
    result = result.slice(1)
  }

  // resolve hex shortcuts
  if (result.length === 3) {
    result = result[0].repeat(2) + result[1].repeat(2) + result[2].repeat(2)
  }

  return result
}

export function hexToTriplet (dirtyHex: string, alpha?: number) {
  const cleanHex = parseHex(dirtyHex)

  const r = parseInt(cleanHex.slice(0, 2), 16)
  const g = parseInt(cleanHex.slice(2, 4), 16)
  const b = parseInt(cleanHex.slice(4, 6), 16)

  return [r, g, b]
}

// values taken from contrast algorithms from w3
// https://www.w3.org/TR/AERT/#color-contrast
export function hexToRgb (dirtyHex: string, alpha?: number) {
  const [r, g, b] = hexToTriplet(dirtyHex)
  const value = `${r}, ${g}, ${b}`

  if (alpha) {
    return `rgba(${value}, ${alpha})`
  }

  return `rgb(${value})`
}