add code to create darker custom colors

Shared/Models/MoodTintable.swift

@@ -123,15 +123,15 @@ final class CustomMoodTint: MoodTintable  {
     static func secondary(forMood mood: Mood) -> Color {
         switch mood {
         case .horrible:
-            return UserDefaultsStore.getCustomMoodTint().colorFive
+            return UserDefaultsStore.getCustomMoodTint().colorFive.darker(by: 40)
         case .bad:
-            return UserDefaultsStore.getCustomMoodTint().colorFour
+            return UserDefaultsStore.getCustomMoodTint().colorFour.darker(by: 40)
         case .average:
-            return  UserDefaultsStore.getCustomMoodTint().colorThree
+            return  UserDefaultsStore.getCustomMoodTint().colorThree.darker(by: 40)
         case .good:
-            return UserDefaultsStore.getCustomMoodTint().colorTwo
+            return UserDefaultsStore.getCustomMoodTint().colorTwo.darker(by: 40)
         case .great:
-            return UserDefaultsStore.getCustomMoodTint().colorOne
+            return UserDefaultsStore.getCustomMoodTint().colorOne.darker(by: 40)
         case .missing:
             return Color(uiColor: UIColor.lightGray)
         case .placeholder:

Shared/Random.swift

@@ -132,6 +132,9 @@ extension Color {
             blue: .random(in: 0...1)
         )
     }
+    
+    public func lighter(by amount: CGFloat = 0.2) -> Self { Self(UIColor(self).lighter(by: amount)) }
+    public func darker(by amount: CGFloat = 0.2) -> Self { Self(UIColor(self).darker(by: amount)) }
 }
 
 extension String {
@@ -151,3 +154,38 @@ extension String {
         return image ?? UIImage()
     }
 }
+
+extension UIColor {
+    
+    func lighter(by percentage: CGFloat = 10.0) -> UIColor {
+        return self.adjust(by: abs(percentage))
+    }
+    
+    func darker(by percentage: CGFloat = 10.0) -> UIColor {
+        return self.adjust(by: -abs(percentage))
+    }
+    
+    func adjust(by percentage: CGFloat) -> UIColor {
+        var alpha, hue, saturation, brightness, red, green, blue, white : CGFloat
+        (alpha, hue, saturation, brightness, red, green, blue, white) = (0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0)
+        
+        let multiplier = percentage / 100.0
+        
+        if self.getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: &alpha) {
+            let newBrightness: CGFloat = max(min(brightness + multiplier*brightness, 1.0), 0.0)
+            return UIColor(hue: hue, saturation: saturation, brightness: newBrightness, alpha: alpha)
+        }
+        else if self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) {
+            let newRed: CGFloat = min(max(red + multiplier*red, 0.0), 1.0)
+            let newGreen: CGFloat = min(max(green + multiplier*green, 0.0), 1.0)
+            let newBlue: CGFloat = min(max(blue + multiplier*blue, 0.0), 1.0)
+            return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: alpha)
+        }
+        else if self.getWhite(&white, alpha: &alpha) {
+            let newWhite: CGFloat = (white + multiplier*white)
+            return UIColor(white: newWhite, alpha: alpha)
+        }
+        
+        return self
+    }
+}