////
/// @author Giana Blantin
////

/// Scales lightness by .1% while checking contrast ratio.
/// @link https://www.w3.org/TR/2016/NOTE-WCAG20-TECHS-20161007/G18#G18-procedure
/// @since 1.12.0 - The Sith
/// @param {Color} $color - Color to be modified
/// @param {Color} $color - Color to be tested against
/// @param {String | Number} $min-ratio - minimum ratio to test against. Accepted values for this ratio argument are AA and AAALG (4.5:1), AALG (3:1) and AAA (7:1) or a number between 1 and 21.
/// @param {Function} $operation - darken() or lighten()
/// @param {Number} $iterations - Number of iterations to perform specified operation
/// @return {Color} - modified color
@function scale-light($color1, $color2, $min-ratio, $operation, $iterations) {
	// Loop this function for however many iterations are passed
	@for $n from 1 through $iterations {
		// Return color unchanged if it passes contrast check
		@if (check-contrast($color1, $color2, $min-ratio)) {
			@return $color1;
		} @else {
			// Otherwise use the built-in lighten() and darken() functions, which change the lightness channel (ie, the L in HSL)
			// Our previous scale-luminance() function changes both saturation and lightness
			$color1: if($operation == lighten, lighten($color1, .1%), darken($color1, .1%));
		}
	}

	// Return the best color we've got
	@return $color1;
}