@function mergeColorMaps($bulma-colors, $custom-colors)

// we return at least bulma hardcoded colors
$merged-colors: $bulma-colors

// we want a map as input
@if type-of($custom-colors) == 'map'
  @each $name, $components in $custom-colors
    // color name should be a string and colors pair a list with at least one element
    @if type-of($name) == 'string' and (type-of($components) == 'list' or type-of($components) == 'color') and length($components) >= 1
      $color-base: null

      // the param can either be a single color
      // or a list of 2 colors
      @if type-of($components) == 'color'
        $color-base: $components
      @else if type-of($components) == 'list'
        $color-base: nth($components, 1)

      $color-invert: null
      // is an inverted color provided in the list
      @if length($components) > 1
        $color-invert: nth($components, 2)

      // we only want a color as base color
      @if type-of($color-base) == 'color'
        // if inverted color is not provided or is not a color we compute it
        @if type-of($color-invert) != 'color'
          $color-invert: findColorInvert($color-base)

        // we merge this colors elements as map with bulma colors (we can override them this way, no multiple definition for the same name)
        $merged-colors: map_merge($merged-colors, ($name: ($color-base, $color-invert)))

@return $merged-colors

@function powerNumber($number, $exp)

$value: 1
@if $exp > 0
  @for $i from 1 through $exp
    $value: $value * $number
@else if $exp < 0
  @for $i from 1 through -$exp
    $value: $value / $number
@return $value

@function colorLuminance($color)

$color-rgb: ('red': red($color),'green': green($color),'blue': blue($color))
@each $name, $value in $color-rgb
  $adjusted: 0
  $value: $value / 255
  @if $value < 0.03928
    $value: $value / 12.92
  @else
    $value: ($value + .055) / 1.055
    $value: powerNumber($value, 2)
  $color-rgb: map-merge($color-rgb, ($name: $value))
@return (map-get($color-rgb, 'red') * .2126) + (map-get($color-rgb, 'green') * .7152) + (map-get($color-rgb, 'blue') * .0722)

@function findColorInvert($color)

@if (colorLuminance($color) > 0.55)
  @return rgba(#000, 0.7)
@else
  @return #fff