var toRgb = require('hsl-to-rgb-for-reals')

// Typically all dependencies should be declared at the top of the file.

// Now let's define an API for our module, we're taking hue, saturation and luminosity values and outputting a CSS compatible hex string.
// Hue is in degrees, between 0 and 359. Since degrees a cyclical in nature, we'll support numbers greater than 359 or less than 0 by "spinning" them around until they fall within the 0 to 359 range.
// Saturation and luminosity are both percentages, we'll represent these percentages with whole numbers between 0 and 100. For these numbers we'll need to enforce a maximum and a minimum, anything below 0 will become 0, anything above 100 will become 100.
// Let's write some utility functions to handle this logic:

function max (val, n) {
  return (val > n) ? n : val
}

function min (val, n) {
  return (val < n) ? n : val
}

function cycle (val) {
  // for safety:
  val = max(val, 1e7)
  val = min(val, -1e7)
  // cycle value:
  while (val < 0) { val += 360 }
  while (val > 359) { val -= 360 }
  return val
}

// Now for the main piece, the `hsl` function:

function hsl (hue, saturation, luminosity) {
  // resolve degrees to 0 - 359 range
  hue = cycle(hue)

  // enforce constraints
  saturation = min(max(saturation, 100), 0)
  luminosity = min(max(luminosity, 100), 0)

  // convert to 0 to 1 range used by hsl-to-rgb-for-reals
  saturation /= 100
  luminosity /= 100

  // let hsl-to-rgb-for-reals do the hard work
  var rgb = toRgb(hue, saturation, luminosity)

  // convert each value in the returned RGB array
  // to a 2 character hex value, join the array into
  // a string, prefixed with a hash
  return '#' + rgb
    .map(function (n) {
      return (256 + n).toString(16).substr(-2)
    })
    .join('')
}

// In order to make our code into a bona fide module we have to export it:

module.exports = hsl
