HexColor and NSColor byway value transformer

HexAndNSColorTransformer.swift

//
//  HexAndNSColorTransformer.swift
//  Charleston
//
//  Created by Чайка on 2018/08/08.
//  Copyright © 2018 Чайка. All rights reserved.
//

import Cocoa

class HexAndNSColorTransformer: ValueTransformer {
	override class func transformedValueClass() -> AnyClass {
		return NSString.self
	}// end class func transformedValueClass
	
	override class func allowsReverseTransformation() -> Bool {
		return true
	}// end class func allowsReverseTransformation
	
	override func transformedValue(_ value: Any?) -> Any? {
		guard let color: NSColor = value as? NSColor else { return "#ffffff" }
		var red: CGFloat = 0.0
		var green: CGFloat = 0.0
		var blue: CGFloat = 0.0
		var alpha: CGFloat = 0.0
		color.getRed(&red, green: &green, blue: &blue, alpha: &alpha)

		let hexColor: NSMutableString = NSMutableString(string: "#")
		[red, green, blue].forEach { (elem) in
			let element: String = String(format: "%02d", (elem * CGFloat(0xff)))
			hexColor.append(element)
		}// end foreach color element
		if alpha != 0.0 {
			let a: String = String(format: "%02d", (alpha * CGFloat(0xff)))
			hexColor.append(a)
		}// end if color have alpha element

		return hexColor
	}// end transformedValue

	override func reverseTransformedValue(_ value: Any?) -> Any? {
		guard let hexColor: NSString = value as? NSString else { return NSColor.white }
		guard hexColor.substring(with: NSMakeRange(0, 1)) == "#" else { return NSColor.white }
		let len: Int = hexColor.length
		if len == 7 || len == 9 {
			var red: CGFloat = 0.0, green: CGFloat = 0.0, blue: CGFloat = 0.0, alpha: CGFloat = 0.0
			let hexRed: String = hexColor.substring(with: NSMakeRange(1, 2))
			red = CGFloat(UInt(hexRed, radix: 16) ?? 0) / CGFloat(0xff)
			let hexGreen: String = hexColor.substring(with: NSMakeRange(3, 2))
			green = CGFloat(UInt(hexGreen, radix: 16) ?? 0) / CGFloat(0xff)
			let hexBlue: String = hexColor.substring(with: NSMakeRange(5, 2))
			blue = CGFloat(UInt(hexBlue, radix: 16) ?? 0) / CGFloat(0xff)
			if len == 9 {
				let hexAlpha: String = hexColor.substring(with: NSMakeRange(7, 2))
				alpha = CGFloat(UInt(hexAlpha, radix: 16) ?? 0) / CGFloat(0xff)
			}// end if string

			return NSColor(calibratedRed: red, green: green, blue: blue, alpha: alpha)
		} else {
			return NSColor.white
		}// end if much length
	}// end reverseTransformedValue
}// end class HexAndNSColorTransformer

extension NSValueTransformerName {
	static let HexAndNSColorTransformerName = NSValueTransformerName(rawValue: "HexAndNSColorTransformer")
}// end extension NSValueTransformerName