// Bootstrap functions
//
// Utility mixins and functions for evaluating source code across our variables, maps, and mixins.

// Ascending
// Used to evaluate Sass maps like our grid breakpoints.
@mixin _assert-ascending($map, $map-name) {
  $prev-key: null;
  $prev-num: null;

  @each $key, $num in $map {
    @if $prev-num == null or unit($num) == "%" or unit($prev-num) == "%" {
      // Do nothing
    } @else if not comparable($prev-num, $num) {
      @warn "Potentially invalid value for #{$map-name}: This map must be in ascending order, but key '#{$key}' has value #{$num} whose unit makes it incomparable to #{$prev-num}, the value of the previous key '#{$prev-key}' !";
    } @else if $prev-num >= $num {
      @warn "Invalid value for #{$map-name}: This map must be in ascending order, but key '#{$key}' has value #{$num} which isn't greater than #{$prev-num}, the value of the previous key '#{$prev-key}' !";
    }
    $prev-key: $key;
    $prev-num: $num;
  }
}

@function negativify-map($map) {
  $result: ();

  @each $key, $value in $map {
    @if $key != 0 {
      $result: map-merge($result, ("n" + $key: (-$value)));
    }
  }

  @return $result;
}

// Replace `$search` with `$replace` in `$string`
// Used on our SVG icon backgrounds for custom forms.
//
// @author Hugo Giraudel
// @param {String} $string - Initial string
// @param {String} $search - Substring to replace
// @param {String} $replace ('') - New value
// @return {String} - Updated string
@function str-replace($string, $search, $replace: "") {
  $index: str-index($string, $search);

  @if $index {
    @return str-slice($string, 1, $index - 1) + $replace + str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
  }

  @return $string;
}

// Color contrast
// See https://github.com/twbs/bootstrap/pull/30168

// A list of pre-calculated numbers of pow(divide((divide($value, 255) + .055), 1.055), 2.4). (from 0 to 255)
// stylelint-disable-next-line scss/dollar-variable-default, scss/dollar-variable-pattern
$_luminance-list: .0008 .001 .0011 .0013 .0015 .0017 .002 .0022 .0025 .0027 .003 .0033 .0037 .004 .0044 .0048 .0052 .0056 .006 .0065 .007 .0075 .008 .0086 .0091 .0097 .0103 .011 .0116 .0123 .013 .0137 .0144 .0152 .016 .0168 .0176 .0185 .0194 .0203 .0212 .0222 .0232 .0242 .0252 .0262 .0273 .0284 .0296 .0307 .0319 .0331 .0343 .0356 .0369 .0382 .0395 .0409 .0423 .0437 .0452 .0467 .0482 .0497 .0513 .0529 .0545 .0561 .0578 .0595 .0612 .063 .0648 .0666 .0685 .0704 .0723 .0742 .0762 .0782 .0802 .0823 .0844 .0865 .0887 .0908 .0931 .0953 .0976 .0999 .1022 .1046 .107 .1095 .1119 .1144 .117 .1195 .1221 .1248 .1274 .1301 .1329 .1356 .1384 .1413 .1441 .147 .15 .1529 .1559 .159 .162 .1651 .1683 .1714 .1746 .1779 .1812 .1845 .1878 .1912 .1946 .1981 .2016 .2051 .2086 .2122 .2159 .2195 .2232 .227 .2307 .2346 .2384 .2423 .2462 .2502 .2542 .2582 .2623 .2664 .2705 .2747 .2789 .2831 .2874 .2918 .2961 .3005 .305 .3095 .314 .3185 .3231 .3278 .3325 .3372 .3419 .3467 .3515 .3564 .3613 .3663 .3712 .3763 .3813 .3864 .3916 .3968 .402 .4072 .4125 .4179 .4233 .4287 .4342 .4397 .4452 .4508 .4564 .4621 .4678 .4735 .4793 .4851 .491 .4969 .5029 .5089 .5149 .521 .5271 .5333 .5395 .5457 .552 .5583 .5647 .5711 .5776 .5841 .5906 .5972 .6038 .6105 .6172 .624 .6308 .6376 .6445 .6514 .6584 .6654 .6724 .6795 .6867 .6939 .7011 .7084 .7157 .7231 .7305 .7379 .7454 .7529 .7605 .7682 .7758 .7835 .7913 .7991 .807 .8148 .8228 .8308 .8388 .8469 .855 .8632 .8714 .8796 .8879 .8963 .9047 .9131 .9216 .9301 .9387 .9473 .956 .9647 .9734 .9823 .9911 1;

@function contrast-ratio($background, $foreground: $color-contrast-light) {
  $la: luminance($background);
  $lb: luminance(opaque($background, $foreground));

  @return if($la > $lb, divide($la + .05, $lb + .05), divide($lb + .05, $la + .05));
}

// Return WCAG2.0 relative luminance
// See https://www.w3.org/WAI/GL/wiki/Relative_luminance
// See https://www.w3.org/TR/WCAG20-TECHS/G17.html#G17-tests
@function luminance($color) {
  $rgb: (
          "r": red($color),
          "g": green($color),
          "b": blue($color)
  );

  @each $name, $value in $rgb {
    $value: if(divide($value, 255) < .03928, divide(divide($value, 255), 12.92), nth($_luminance-list, $value + 1));
    $rgb: map-merge($rgb, ($name: $value));
  }

  @return (map-get($rgb, "r") * .2126) + (map-get($rgb, "g") * .7152) + (map-get($rgb, "b") * .0722);
}

// Return opaque color
// opaque(#fff, rgba(0, 0, 0, .5)) => #808080
@function opaque($background, $foreground) {
  @return mix(rgba($foreground, 1), $background, opacity($foreground) * 100);
}

@function divide($dividend, $divisor, $precision: 10) {
  $sign: if($dividend > 0 and $divisor > 0 or $dividend < 0 and $divisor < 0, 1, -1);
  $dividend: abs($dividend);
  $divisor: abs($divisor);

  @if $dividend == 0 {
    @return 0;
  }

  @if $divisor == 0 {
    @error "Cannot divide by 0";
  }
  $remainder: $dividend;
  $result: 0;
  $factor: 10;

  @while ($remainder > 0 and $precision >= 0) {
    $quotient: 0;

    @while ($remainder >= $divisor) {
      $remainder: $remainder - $divisor;
      $quotient: $quotient + 1;
    }
    $result: $result * 10 + $quotient;
    $factor: $factor * .1;
    $remainder: $remainder * 10;
    $precision: $precision - 1;

    @if ($precision < 0 and $remainder >= $divisor * 5) {
      $result: $result + 1;
    }
  }
  $result: $result * $factor * $sign;
  $dividend-unit: unit($dividend);
  $divisor-unit: unit($divisor);
  $unit-map: (
          "px": 1px,
          "rem": 1rem,
          "em": 1em,
          "%": 1%
  );

  @if ($dividend-unit != $divisor-unit and map-has-key($unit-map, $dividend-unit)) {
    $result: $result * map-get($unit-map, $dividend-unit);
  }

  @return $result;
}