/**
 * functions
 *
 *
 *
 *
 * @author Björn Hase
 * @license http://opensource.org/licenses/MIT The MIT License
 * @link https://gitlab.tentakelfabrik.de/tentakelfabrik/crispy
 *
 */

 /**
  * px to em, wrapper of toRelatives
  *
  * @param  {mixed} $values
  * @param  {mixed} $base
  * @return {rem}
  */
@function toEm($values, $base: $crispy__font-size) {
    @return toRelatives($values, 1em, $base);
}

/**
 * px to rem, wrapper of toRelatives
 *
 * @param  {mixed} $values
 * @param  {mixed} $base
 * @return {rem}
 */
@function toRem($values, $base: $crispy__font-size) {
    @return toRelatives($values, 1rem, $base);
}

/**
 * values to relative
 *
 * @param  {mixed} $values
 * @param  {mixed} $unit
 * @param  {mixed} $base
 * @return {number}
 */
@function toRelatives($values, $unit, $base: $crispy__font-size) {
    $results: 0;

    @if type-of($values) == 'number' {
		$results: toRelative($values, $base) * $unit;
    } @else {
        $results: ();

        @each $value in $values {
			@if $value == 0 {
				$results: append($results, $value);
			}
			@else {
				$results: append($results, toRelative($value, $base) * $unit);
			}
        }
    }

    @return $results;
}

/**
 * to relative
 *
 * @param  {mixed} $value
 * @param  {mixed} $base
 * @return {number}
 */
@function toRelative($value, $base: $crispy__font-size) {
    @return stripUnit($value) / stripUnit($base);
}

/**
 * strip unit from value
 *
 * @param  {mixed} $value
 * @return {number}
 */
@function stripUnit($value) {
    @return $value / ($value * 0 + 1);
}

/**
 * function: z-index
 *
 * uses map $crispy__z-index to get value by key
 *
 * @author Björn Hase
 *
 */

@function zIndex($name) {
    @if map-has-key($crispy__z-index, $name) {
        @return map-get($crispy__z-index, $name);
    } @else {
        @warn 'There is no item "#{$name}" in this list; choose one of: #{$crispy__z-index}';
        @return null;
    }
}

/**
 *
 *
 *
 * @param  {[type]} $directions [description]
 * @return {[type]}             [description]
 * 
 */
@function opposite-direction($directions) {
  $opposite-directions: ();
  $direction-map: (
    'top':    'bottom',
    'right':  'left',
    'bottom': 'top',
    'left':   'right',
    'center': 'center',
    'ltr':    'rtl',
    'rtl':    'ltr'
  );

  @each $direction in $directions {
    $direction: to-lower-case($direction);

    @if map-has-key($direction-map, $direction) {
      $opposite-directions: append($opposite-directions, unquote(map-get($direction-map, $direction)));
    } @else {
      @warn "No opposite direction can be found for `#{$direction}`. Direction omitted.";
    }
  }

  @return $opposite-directions;
}