// Checks if a number is even
@function is-even($int) {
	@if $int%2 == 0 {
		@return true;
	}

	@return false;
}

// Checks if an element belongs to a list
@function belongs-to($tested-item, $list) {
	@each $item in $list {
		@if $item == $tested-item {
			@return true;
		}
	}

	@return false;
}

// Contains display value
@function contains-display-value($query) {
	@if belongs-to(table, $query) or belongs-to(block, $query) or belongs-to(inline-block, $query) or belongs-to(inline, $query) {
		@return true;
	}

	@return false;
}

// Parses the first argument of span-columns()
@function container-span($span: $span) {
	@if length($span) == 3 {
		$container-columns: nth($span, 3);
		@return $container-columns;
	} @else if length($span) == 2 {
		$container-columns: nth($span, 2);
		@return $container-columns;
	} @else {
		@return $grid-columns;
	}
}

@function container-shift($shift: $shift) {
	$parent-columns: $grid-columns !global !default;

	@if length($shift) == 3 {
		$container-columns: nth($shift, 3);
		@return $container-columns;
	} @else if length($shift) == 2 {
		$container-columns: nth($shift, 2);
		@return $container-columns;
	} @else {
		@return $parent-columns;
	}
}

// Generates a striped background
@function gradient-stops($grid-columns, $color: $visual-grid-color) {
	$transparent: rgba(0, 0, 0, 0);

	$column-width: flex-grid(1, $grid-columns);
	$gutter-width: flex-gutter($grid-columns);
	$column-offset: $column-width;

	$values: ($transparent 0, $color 0);

	@for $i from 1 to $grid-columns*2 {
		@if is-even($i) {
			$values: append($values, $transparent $column-offset, comma);
			$values: append($values, $color $column-offset, comma);
			$column-offset: $column-offset + $column-width;
		} @else {
			$values: append($values, $color $column-offset, comma);
			$values: append($values, $transparent $column-offset, comma);
			$column-offset: $column-offset + $gutter-width;
		}
	}

	@return $values;
}

// Layout direction
@function get-direction($layout, $default) {
	$direction: nil;

	@if $layout == LTR or $layout == RTL {
		$direction: direction-from-layout($layout);
	} @else {
		$direction: direction-from-layout($default);
	}

	@return $direction;
}

@function direction-from-layout($layout) {
	$direction: nil;

	@if $layout == LTR {
		$direction: right;
	} @else {
		$direction: left;
	}

	@return $direction;
}

@function get-opposite-direction($direction) {
	$opposite-direction: left;

	@if $direction == left {
		$opposite-direction: right;
	}

	@return $opposite-direction;
}
