Introduce color provider to encapsulate check for iOS 13 availability

passKit/Helpers/Colors.swift

@@ -0,0 +1,51 @@
+//
+//  Colors.swift
+//  passKit
+//
+//  Created by Danny Moesch on 01.10.19.
+//  Copyright © 2019 Bob Sun. All rights reserved.
+//
+
+public struct Colors {
+    public static let label: UIColor = {
+        if #available(iOS 13.0, *) {
+            return .label
+        }
+        return .black
+    }()
+
+    public static let secondaryLabel: UIColor = {
+        if #available(iOS 13.0, *) {
+            return .secondaryLabel
+        }
+        return .init(red: 60.0, green: 60.0, blue: 67.0, alpha: 0.6)
+    }()
+
+    public static let systemBackground: UIColor = {
+        if #available(iOS 13.0, *) {
+            return .systemBackground
+        }
+        return .white
+    }()
+
+    public static let secondarySystemBackground: UIColor = {
+        if #available(iOS 13.0, *) {
+            return .secondarySystemBackground
+        }
+        return .init(red: 242.0, green: 242.0, blue: 247.0, alpha: 1.0)
+    }()
+
+    public static let systemRed: UIColor = {
+        if #available(iOS 13.0, *) {
+            return .systemRed
+        }
+        return .red
+    }()
+
+    public static let systemBlue: UIColor = {
+        if #available(iOS 13.0, *) {
+            return .systemBlue
+        }
+        return .blue
+    }()
+}

passKit/Helpers/Globals.swift

@@ -41,14 +41,6 @@ public class Globals {
     public static let passwordFont = UIFont(name: "Courier-Bold", size: UIFont.labelFontSize - 1)
 
     // UI related
-    public static let red = UIColor.systemRed
-    public static let blue = UIColor.systemBlue
-    public static let black: UIColor = {
-        if #available(iOSApplicationExtension 13.0, *) {
-            return UIColor.label
-        }
-        return UIColor.black
-    }()
     public static let tableCellButtonSize = CGFloat(20.0)
 
     private init() { }

passKit/Helpers/Utils.swift

@@ -22,11 +22,11 @@ public class Utils {
         for (index, element) in plainPassword.unicodeScalars.enumerated() {
             var charColor = UIColor.darkText
             if NSCharacterSet.decimalDigits.contains(element) {
-                charColor = Globals.red
+                charColor = Colors.systemRed
             } else if !NSCharacterSet.letters.contains(element) {
-                charColor = Globals.blue
+                charColor = Colors.systemBlue
             } else {
-                charColor = Globals.black
+                charColor = Colors.label
             }
             attributedPassword.addAttribute(NSAttributedString.Key.foregroundColor, value: charColor, range: NSRange(location: index, length: 1))
         }