@use "sass:color";
@use "sass:list";
@use "sass:map";
@use "sass:meta";
@use "sass:string";

@function is-upper-case($char) {
  @return string.to-lower-case($char) != $char;
}

@function is-lower-case($char) {
  @return string.to-upper-case($char) != $char;
}

@function camel-to-kebab($string) {
  $length: string.length($string);
  $property: "--";

  @for $i from 1 through $length {
    $char: string.slice($string, $i, $i);
    $property: "#{$property}#{if(is-upper-case($char), "-#{string.to-lower-case(
        $char
      )}",$char)}";
  }

  @return $property;
}

@function color-is-legal($value) {
  // single color
  @if meta.type-of($value) == color {
    @return true;
  }

  // it’s a valid map color config
  @if (
    (meta.type-of($value) == map) and
      (meta.type-of(map.get($value, "light")) == color) and
      (meta.type-of(map.get($value, "dark")) == color)
  ) {
    @return true;
  }

  @warn "Unexpected variable value: getting #{$value}";
  @return false;
}

@function get-color($color, $is-dark: false) {
  @if meta.type-of($color) == color {
    @return $color;
  }

  $light-color: map.get($color, "light");
  $dark-color: map.get($color, "dark");

  @if $light-color and $dark-color {
    @return if($is-dark, $dark-color, $light-color);
  }

  @warn "Unexpected color: getting #{$color}";
  @return transparent;
}

@function get-dark-color($color) {
  @return get-color($color, $is-dark: true);
}

@function get-variables($variables, $dark-selector: "") {
  $root-variables: ();
  $dark-variables: ();

  @each $name, $value in $variables {
    $key: camel-to-kebab($name);

    @if meta.type-of($value) == number or meta.type-of($value) == string {
      $root-variables: map.set($root-variables, $key, $value);
    } @else if color-is-legal($value) {
      $light-color: get-color($value, false);
      $root-variables: map.set($root-variables, $key, $light-color);

      @if $dark-selector {
        $dark-color: get-color($value, true);

        @if $light-color != $dark-color {
          $dark-variables: map.set(
            $dark-variables,
            $key,
            get-color($value, true)
          );
        }
      }
    }
  }

  @return ("root": $root-variables, "dark": $dark-variables);
}

@mixin inject-color($key, $config, $dark-selector: "") {
  @if meta.type-of($config) == color {
    :root {
      #{$key}: #{$config};
    }
  } @else {
    $light-color: map.get($config, "light");
    $dark-color: map.get($config, "dark");

    @if $light-color and $dark-color {
      :root {
        #{$key}: #{$light-color};
      }

      @if $light-color != $dark-color and $dark-selector {
        #{$dark-selector} {
          #{$key}: #{$dark-color};
        }
      }
    }
  }
}

@mixin inject($variables, $dark-selector: "") {
  $result: get-variables($variables, $dark-selector);
  $root-variables: map.get($result, "root");
  $dark-variables: map.get($result, "dark");

  @if $dark-selector {
    #{$dark-selector} {
      @each $key, $value in $dark-variables {
        #{$key}: #{$value};
      }
    }
  }

  :root {
    @each $key, $value in $root-variables {
      #{$key}: #{$value};
    }
  }
}