// Bootstrap functions
//
// Utility mixins and functions for evalutating 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 $prev-num == null {
            // Do nothing
        } @else if not comparable($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;
    }
}

// Starts at zero
// Another grid mixin that ensures the min-width of the lowest breakpoint starts at 0.
@mixin _assert-starts-at-zero($map) {
    $values: map-values($map);
    $first-value: nth($values, 1);
    @if $first-value != 0 {
        @warn "First breakpoint in `$grid-breakpoints` must start at 0, but starts at #{$first-value}.";
    }
}

// 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
@function color-yiq($color) {
    $r: red($color);
    $g: green($color);
    $b: blue($color);

    $yiq: (($r * 299) + ($g * 587) + ($b * 114)) * 0.001;

    @if ($yiq >= $yiq-contrasted-threshold) {
        @return $yiq-text-dark;
    } @else {
        @return $yiq-text-light;
    }
}

// Retrieve color Sass maps
@function color($key: 'blue') {
    @return map-get($colors, $key);
}

@function theme-color($key: 'primary') {
    @return map-get($theme-colors, $key);
}

@function gray($key: '100') {
    @return map-get($grays, $key);
}

// Request a theme color level
@function theme-color-level($color-name: 'primary', $level: 0) {
    $color: theme-color($color-name);
    $color-base: if($level > 0, $black, $white);
    $level: abs($level);

    @return mix($color-base, $color, $level * $theme-color-interval);
}