// Copyright (c) roydukkey. All rights reserved.
// Licensed under the MIT. See LICENSE file in the project root for full license information.

@use 'sass:color'
@use 'sass:list'
@use 'sass:math'
@use 'sass:meta'
@use '@sass-fairy/exception/src/parameter-type'


///
/// @throw `#{$color}` is not a color.
///
@function luminance($color)

	@if meta.type-of($color) != 'color'
		@error parameter-type.parameter-type('luminance', 'color', $color, 'color')

	$color: color.channel($color, 'red', $space: rgb), color.channel($color, 'green', $space: rgb), color.channel($color, 'blue', $space: rgb)

	@for $i from 1 through 3
		$channel: math.div(list.nth($color, $i), 255)
		$channel: if(sass($channel <= 0.03928): math.div($channel, 12.92); else: math.pow(math.div($channel + 0.055, 1.055), 2.4))
		$color: list.set-nth($color, $i, $channel)

	@return 0.2126 * list.nth($color, 1) + 0.7152 * list.nth($color, 2) + 0.0722 * list.nth($color, 3)