export function getThemeCluster(theme) {
  const tintColor = (color, tint) => {
    let red = parseInt(color.slice(0, 2), 16)
    let green = parseInt(color.slice(2, 4), 16)
    let blue = parseInt(color.slice(4, 6), 16)

    if (tint === 0) { // when primary color is in its rgb space
      return [red, green, blue].join(',')
    } else {
      red += Math.round(tint * (255 - red))
      green += Math.round(tint * (255 - green))
      blue += Math.round(tint * (255 - blue))

      red = red.toString(16)
      green = green.toString(16)
      blue = blue.toString(16)

      return `#${red}${green}${blue}`
    }
  }

  const shadeColor = (color, shade) => {
    let red = parseInt(color.slice(0, 2), 16)
    let green = parseInt(color.slice(2, 4), 16)
    let blue = parseInt(color.slice(4, 6), 16)

    red = Math.round((1 - shade) * red)
    green = Math.round((1 - shade) * green)
    blue = Math.round((1 - shade) * blue)

    red = red.toString(16)
    green = green.toString(16)
    blue = blue.toString(16)

    return `#${red}${green}${blue}`
  }

  const clusters = [theme]
  for (let i = 0; i <= 9; i++) {
    clusters.push(tintColor(theme, Number((i / 10).toFixed(2))))
  }
  clusters.push(shadeColor(theme, 0.1))
  return clusters
}