[Features] Adds @Feature property wrapper

Simplifies defining feature flags that can enabled + disabled via UserDefaults.

Delta.xcodeproj/project.pbxproj

@@ -186,6 +186,7 @@
 		D5D797E9298DCC7300738869 /* cheatbase.zip in Resources */ = {isa = PBXBuildFile; fileRef = D5D797E7298DC9E200738869 /* cheatbase.zip */; };
 		D5D7C1FA29E60EDE00663793 /* libDeltaFeatures.a in Frameworks */ = {isa = PBXBuildFile; fileRef = D5D7C1F129E60DFF00663793 /* libDeltaFeatures.a */; };
 		D5D7C20429E60F2000663793 /* Feature.swift in Sources */ = {isa = PBXBuildFile; fileRef = D5A9BFFD29DDECF100A8D610 /* Feature.swift */; };
+		D5D7C20829E616CF00663793 /* FeatureContainer.swift in Sources */ = {isa = PBXBuildFile; fileRef = D5D7C20729E616CF00663793 /* FeatureContainer.swift */; };
 		D5F82FB82981D3AC00B229AF /* LegacySearchBar.swift in Sources */ = {isa = PBXBuildFile; fileRef = D5F82FB72981D3AC00B229AF /* LegacySearchBar.swift */; };
 /* End PBXBuildFile section */
 
@@ -419,6 +420,7 @@
 		D5D797E5298D946200738869 /* Contributor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Contributor.swift; sourceTree = "<group>"; };
 		D5D797E7298DC9E200738869 /* cheatbase.zip */ = {isa = PBXFileReference; lastKnownFileType = archive.zip; path = cheatbase.zip; sourceTree = "<group>"; };
 		D5D7C1F129E60DFF00663793 /* libDeltaFeatures.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libDeltaFeatures.a; sourceTree = BUILT_PRODUCTS_DIR; };
+		D5D7C20729E616CF00663793 /* FeatureContainer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeatureContainer.swift; sourceTree = "<group>"; };
 		D5F82FB72981D3AC00B229AF /* LegacySearchBar.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LegacySearchBar.swift; sourceTree = "<group>"; };
 		DC866E433B3BA9AE18ABA1EC /* libPods-Delta.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = "libPods-Delta.a"; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
@@ -1013,6 +1015,7 @@
 			children = (
 				D5A9BFFD29DDECF100A8D610 /* Feature.swift */,
 				D517F6BB29E737F5000D14D0 /* Types */,
+				D5D7C1FE29E60EF700663793 /* Protocols */,
 				D5D7C1F829E60E8600663793 /* Extensions */,
 			);
 			path = DeltaFeatures;
@@ -1026,6 +1029,14 @@
 			path = Extensions;
 			sourceTree = "<group>";
 		};
+		D5D7C1FE29E60EF700663793 /* Protocols */ = {
+			isa = PBXGroup;
+			children = (
+				D5D7C20729E616CF00663793 /* FeatureContainer.swift */,
+			);
+			path = Protocols;
+			sourceTree = "<group>";
+		};
 		FD1E8AE87FA2DB8793F7B937 /* Pods */ = {
 			isa = PBXGroup;
 			children = (
@@ -1504,6 +1515,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D5D7C20829E616CF00663793 /* FeatureContainer.swift in Sources */,
 				D517F6BA29E730DA000D14D0 /* SettingsName.swift in Sources */,
 				D5D7C20429E60F2000663793 /* Feature.swift in Sources */,
 				D54F710429E89DFC009C069A /* NotificationName+Settings.swift in Sources */,

DeltaFeatures/Feature.swift

@@ -6,5 +6,43 @@
 //  Copyright © 2023 Riley Testut. All rights reserved.
 //
 
-import Foundation
+import SwiftUI
+import Combine
 
+@propertyWrapper @dynamicMemberLookup
+public final class Feature
+{
+    public let name: LocalizedStringKey
+    public let description: LocalizedStringKey?
+    
+    // Assigned to property name.
+    public internal(set) var key: String = ""
+    
+    // Used for `SettingsUserInfoKey.name` value in .settingsDidChange notification.
+    public var settingsKey: SettingsName {
+        return SettingsName(rawValue: self.key)
+    }
+    
+    public var isEnabled: Bool {
+        get {
+            let isEnabled = UserDefaults.standard.bool(forKey: self.key)
+            return isEnabled
+        }
+        set {
+            self.objectWillChange.send()
+            UserDefaults.standard.set(newValue, forKey: self.key)
+            
+            NotificationCenter.default.post(name: .settingsDidChange, object: nil, userInfo: [SettingsUserInfoKey.name: self.settingsKey, SettingsUserInfoKey.value: newValue])
+        }
+    }
+    
+    public var wrappedValue: Feature {
+        return self
+    }
+    
+    public init(name: LocalizedStringKey, description: LocalizedStringKey? = nil)
+    {
+        self.name = name
+        self.description = description
+    }
+}

DeltaFeatures/Protocols/FeatureContainer.swift

@@ -0,0 +1,36 @@
+//
+//  FeatureContainer.swift
+//  DeltaFeatures
+//
+//  Created by Riley Testut on 4/11/23.
+//  Copyright © 2023 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+public protocol FeatureContainer
+{
+    static var shared: Self { get }
+}
+
+public extension FeatureContainer
+{    
+    var allFeatures: [Feature] {
+        let features = Mirror(reflecting: self).children.compactMap { (child) -> Feature? in
+            let feature = child.value as? Feature
+            return feature
+        }
+        return features
+    }
+    
+    func prepareFeatures()
+    {
+        // Assign keys to property names.
+        for case (let key?, let feature as Feature) in Mirror(reflecting: self).children
+        {
+            // Remove leading underscore.
+            let sanitizedKey = key.dropFirst()
+            feature.key = String(sanitizedKey)
+        }
+    }
+}