@use 'sass:color';
@use 'sass:list';
@use 'sass:math';
@use 'sass:map';

@function color-contrast($bg, $fg) {
  $luminance1: luminance($fg) + 0.05;
  $luminance2: luminance($bg) + 0.05;
  $ratio: calc($luminance1 / $luminance2);

  @if $luminance2 > $luminance1 {
    $ratio: 1 / $ratio;
  }

  $ratio: calc(math.round($ratio * 100) / 100);

  @return $ratio;
}

@function luminance($color) {
  $red: list.nth(linear-rgb($color), 1);
  $green: list.nth(linear-rgb($color), 2);
  $blue: list.nth(linear-rgb($color), 3);

  @return 0.2126 * $red + 0.7152 * $green + 0.0722 * $blue;
}

@function linear-rgb($color) {
  $r: calc(color.channel($color, 'red', $space: rgb) / 255);
  $g: calc(color.channel($color, 'green', $space: rgb) / 255);
  $b: calc(color.channel($color, 'blue', $space: rgb) / 255);

  $r: if($r <= 0.03928, calc($r / 12.92), pow(($r + 0.055) / 1.055, 2.4));
  $g: if($g <= 0.03928, calc($g / 12.92), pow(($g + 0.055) / 1.055, 2.4));
  $b: if($b <= 0.03928, calc($b / 12.92), pow(($b + 0.055) / 1.055, 2.4));

  @return ($r, $g, $b);
}