// 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.
=_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.
=_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) / 1000

  @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)