// Ported from http://ariya.blogspot.com/2008/07/converting-between-hsl-and-hsv.html

@function ch-hsv-to-hsl($h, $s: 0, $v: 0) {
  @if type_of($h) == 'list' {
    $v: nth($h, 3);
    $s: nth($h, 2);
    $h: nth($h, 1);
  }

  @if unit($h) == 'deg' {
    $h: 3.1415 * 2 * ($h / 360deg);
  }

  @if unit($s) == '%' {
    $s: 0 + (round($s) / 100%);
  }

  @else {
    $s: $s / 100;
  }

  @if unit($v) == '%' {
    $v: if($v >= 100, 1, $v / 100%);
  }

  $ss: $s * $v;
  $ll: (2 - $s) * $v;

  @if ($ll == 2 or $ll == 0) {
    $ss: 0;
  }

  @else if $ll <= 1 {
    $ss: $ss / $ll;
  }

  @else {
    $ss: $ss / (2 - $ll);
  }

  $ll: $ll / 2;

  @return 360deg * $h / (3.1415 * 2), percentage(max(0, min(1, $ss))), percentage(max(0, min(1, $ll)));
}

@function ch-hsl-to-hsv($h, $ss: 0, $ll: 0) {
  @if type_of($h) == 'list' {
    $ll: nth($h, 3);
    $ss: nth($h, 2);
    $h: nth($h, 1);
  }

  @else if type_of($h) == 'color' {
    $ll: lightness($h);
    $ss: saturation($h);
    $h: hue($h);
  }

  @if unit($h) == 'deg' {
    $h: 3.1415 * 2 * ($h / 360deg);
  }

  @if unit($ss) == '%' {
    $ss: 0 + ($ss / 100%);
  }

  @if unit($ll) == '%' {
    $ll: 0 + ($ll / 100%);
  }

  $ll: $ll * 2;

  @if $ll <= 1 {
    $ss: $ss * $ll;
  }

  @else {
    $ss: $ss * (2 - $ll);
  }

  $v: ($ll + $ss) / 2;

  $s: 0;

  @if $ll + $ss != 0 {
    $s: (2 * $ss) / ($ll + $ss);
  }

  @return 360deg * $h / (3.1415 * 2), percentage(max(0, min(1, $s))), percentage(max(0, min(1, $v)));
}

@function ch-color-to-hsv($color) {
  @return ch-hsl-to-hsv($color);
}

@function ch-hsv-to-color($h, $s: 0, $v: 0) {
  $hsl: ch-hsv-to-hsl($h, $s, $v);

  @return hsla(nth($hsl, 1), nth($hsl, 2), nth($hsl, 3), 1);
}

@function ch-brightness($h, $s: 0, $v: 0, $adjustment: 0) {
  @if type_of($h) == 'color' {
    $h: ch-color-to-hsv($h);
  }

  @if type_of($h) == 'list' {
    $adjustment: $s;
    $v: nth($h, 3);
    $s: nth($h, 2);
    $h: nth($h, 1);
  }

  $v: ch-max(0%, ch-min(100%, $v + $adjustment));

  @return ch-hsv-to-color($h, $s, $v);
}