@function -zf-flex-justify($text-direction){
  $-zf-flex-justify: (
    'left': if($text-direction == rtl, flex-end, flex-start),
    'right': if($text-direction == rtl, flex-start, flex-end),
    'center': center,
    'justify': space-between,
    'spaced': space-around,
  );

  @return $-zf-flex-justify;
}


$-zf-flex-align: (
  'top': flex-start,
  'bottom': flex-end,
  'middle': center,
  'stretch': stretch,
);

$-zf-flex-direction: (
  'row': row,
  'row-reverse': row-reverse,
  'column': column,
  'column-reverse': column-reverse,
);

/// Enables flexbox by adding `display: flex` to the element.
@mixin flex {
  display: flex;
}

/// Horizontally or vertically aligns the items within a flex container.
///
/// @param {Keyword} $x [null] - Horizontal alignment to use. Can be `left`, `right`, `center`, `justify`, or `spaced`. Or, set it to `null` (the default) to not set horizontal alignment.
/// @param {Keyword} $y [null] - Vertical alignment to use. Can be `top`, `bottom`, `middle`, or `stretch`. Or, set it to `null` (the default) to not set vertical alignment.
@mixin flex-align($x: null, $y: null) {
  @if $x {
    @if map-has-key($-zf-flex-justify, $x) {
      $x: map-get($-zf-flex-justify, $x);
    }
    @else {
      @warn 'flex-grid-row-align(): #{$x} is not a valid value for horizontal alignment. Use left, right, center, justify, or spaced.';
    }
  }

  @if $y {
    @if map-has-key($-zf-flex-align, $y) {
      $y: map-get($-zf-flex-align, $y);
    }
    @else {
      @warn 'flex-grid-row-align(): #{$y} is not a valid value for vertical alignment. Use top, bottom, middle, or stretch.';
    }
  }

  justify-content: $x;
  align-items: $y;
}

/// Vertically align a single column within a flex row. Apply this mixin to a flex column.
///
/// @param {Keyword} $y [null] - Vertical alignment to use. Can be `top`, `bottom`, `middle`, or `stretch`. Or, set it to `null` (the default) to not set vertical alignment.
@mixin flex-align-self($y: null) {
  @if $y {
    @if map-has-key($-zf-flex-align, $y) {
      $y: map-get($-zf-flex-align, $y);
    }
    @else {
      @warn 'flex-grid-column-align(): #{$y} is not a valid value for alignment. Use top, bottom, middle, or stretch.';
    }
  }

  align-self: $y;
}

/// Changes the source order of a flex child. Children with lower numbers appear first in the layout.
/// @param {Number} $order [0] - Order number to apply.
@mixin flex-order($order: 0) {
  order: $order;
}

/// Change flex-direction
/// @param {Keyword} $direction [row] - Flex direction to use. Can be
///   - row (default): same as text direction
///   - row-reverse: opposite to text direction
///   - column: same as row but top to bottom
///   - column-reverse: same as row-reverse top to bottom
@mixin flex-direction($direction: row) {
  flex-direction: $direction;
}