@charset "UTF-8";

@mixin text-shadow($params...) {
  $value: ();

  @for $i from 1 through length($params) {
    // Takes each items come from $params.
    $item: nth($params, $i);

    // The first value comes from the $item is direction.
    // This will be used in the @if, @else statements with $size to control the offset of the shadows.
    $direction: nth($item, 1);

    // Second value is the color.
    $color: nth($item, 2);

    // The third value is the actual offset value of the shadows.
    $size: nth($item, 3);

    // Takes the unit of the $size value to use it later to increment the amount of shadow based on the unit.
    $sizeUnit: unit($size);

    // The $blur argument is optional. It controls the size of the blur.
    $blur: null;

    // The $fill argument is optional. This makes shadow fill the gap between the actual text and shadow's end-point. The default value is set to false.
    $fill: null;

    // Assigns the optional sub-arguments to the actual argument.
    @if length($item) == 4 and type-of(nth($item, 4)) == number {
      $blur: nth($item, length($item));
    } @else if length($item) == 4 and type-of(nth($item, 4)) == bool {
      $fill: nth($item, length($item));
    } @else if length($item) == 5 {
      $blur: nth($item, 4);
      $fill: nth($item, length($item));
    }

    // The code below changes the angle of $direction of the shadow based on the predefined values.
    @if $direction == "top" {
      @if $fill == true {
        // The __clearUnit(); function is used here due to it is not possible to count $size with a unit. First, it clears the unit from the $size argument and then adds it back again in the @for loop.
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: 0 -#{$increase} $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: 0 -#{$size} $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "top-left" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: -#{$increase} -#{$increase} $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: -#{$size} -#{$size} $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "top-right" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: #{$increase} -#{$increase} $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: #{$size} -#{$size} $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "bottom" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: 0 #{$increase} $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: 0 #{$size} $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "bottom-left" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: -#{$increase} #{$increase} $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: -#{$size} #{$size} $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "bottom-right" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: #{$increase} #{$increase} $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: #{$size} #{$size} $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "left" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: -#{$increase} 0 $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: -#{$size} 0 $blur $color;
        $value: append($value, $shadow, comma);
      }
    } @else if $direction == "right" {
      @if $fill == true {
        @for $i from 1 through __clearUnit($size) {
          $increase: $i * 1 + $sizeUnit;
          $shadow: #{$increase} 0 $blur $color;
          $value: append($value, $shadow, comma);
        }
      } @else {
        $shadow: #{$size} 0 $blur $color;
        $value: append($value, $shadow, comma);
      }
    }
  }
  text-shadow: $value;
}