// Foundation for Sites by ZURB // foundation.zurb.com // Licensed under MIT Open Source

@import 'math';

$contrast-warnings: true !default;

//// /// @group functions ////

/// Checks the luminance of `$color`. /// /// @param {Color} $color - Color to check the luminance of. /// /// @returns {Number} The luminance of `$color`. @function color-luminance($color) {

// Adapted from: https://github.com/LeaVerou/contrast-ratio/blob/gh-pages/color.js
// Formula: http://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
$rgba: red($color), green($color), blue($color);
$rgba2: ();

@for $i from 1 through 3 {
  $rgb: nth($rgba, $i);
  $rgb: $rgb / 255;

  $rgb: if($rgb < 0.03928, $rgb / 12.92, pow(($rgb + 0.055) / 1.055, 2.4));

  $rgba2: append($rgba2, $rgb);
}

@return 0.2126 * nth($rgba2, 1) + 0.7152 * nth($rgba2, 2) + 0.0722 * nth($rgba2, 3);

}

/// Checks the contrast ratio of two colors. /// /// @param {Color} $color1 - First color to compare. /// @param {Color} $color2 - Second color to compare. /// /// @returns {Number} The contrast ratio of the compared colors. @function color-contrast($color1, $color2) {

// Adapted from: https://github.com/LeaVerou/contrast-ratio/blob/gh-pages/color.js
// Formula: http://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef
$luminance1: color-luminance($color1) + 0.05;
$luminance2: color-luminance($color2) + 0.05;
$ratio: $luminance1 / $luminance2;

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

$ratio: round($ratio * 10) / 10;

@return $ratio;

}

/// Checks the luminance of `$base`, and returns the color from `$colors` (list of colors) that has the most contrast. /// /// @param {Color} $base - Color to check luminance. /// @param {List} $colors [($white, $black)] - Colors to compare. /// @param {Number} $tolerance [$global-color-pick-contrast-tolerance] - Contrast tolerance. /// /// @returns {Color} the color from `$colors` (list of colors) that has the most contrast. @function color-pick-contrast($base, $colors: ($white, $black), $tolerance: $global-color-pick-contrast-tolerance) {

$contrast: color-contrast($base, nth($colors, 1));
$best: nth($colors, 1);

@for $i from 2 through length($colors) {
  $current-contrast: color-contrast($base, nth($colors, $i));
  @if ($current-contrast - $contrast > $tolerance) {
    $contrast: color-contrast($base, nth($colors, $i));
    $best: nth($colors, $i);
  }
}

@if ($contrast-warnings and $contrast < 3) {
  @warn "Contrast ratio of #{$best} on #{$base} is pretty bad, just #{$contrast}";
}

@return $best;

}

/// Scales a color to be darker if it's light, or lighter if it's dark. Use this function to tint a color appropriate to its lightness. /// /// @param {Color} $color - Color to scale. /// @param {Percentage} $scale [5%] - Amount to scale up or down. /// @param {Percentage} $threshold [40%] - Threshold of lightness to check against. /// /// @returns {Color} A scaled color. @function smart-scale($color, $scale: 5%, $threshold: 40%) {

@if lightness($color) > $threshold {
  $scale: -$scale;
}
@return scale-color($color, $lightness: $scale);

}

/// Get color from foundation-palette /// /// @param {key} color key from foundation-palette /// /// @returns {Color} color from foundation-palette @function get-color($key) {

@if map-has-key($foundation-palette, $key) {
  @return map-get($foundation-palette, $key);
}
@else {
  @error 'given $key is not available in $foundation-palette';
}

}

/// Transfers the colors in the `$foundation-palette`map into variables, such as `$primary-color` and `$secondary-color`. Call this mixin below the Global section of your settings file to properly migrate your codebase. @mixin add-foundation-colors() {

@if map-has-key($foundation-palette, primary) {
  $primary-color: map-get($foundation-palette, primary) !global;
}
@if map-has-key($foundation-palette, secondary) {
  $secondary-color: map-get($foundation-palette, secondary) !global;
}
@if map-has-key($foundation-palette, success) {
  $success-color: map-get($foundation-palette, success) !global;
}
@if map-has-key($foundation-palette, warning) {
  $warning-color: map-get($foundation-palette, warning) !global;
}
@if map-has-key($foundation-palette, alert) {
  $alert-color: map-get($foundation-palette, alert) !global;
}

}