From 13b5ea2a559588ce5599fe9cb014f6e196839176 Mon Sep 17 00:00:00 2001
From: Matt Bruce <matt.bruce@verizon.com>
Date: Fri, 29 Jul 2022 16:06:32 -0500
Subject: [PATCH] forwarding proxy propertywrapper

Signed-off-by: Matt Bruce <matt.bruce@verizon.com>
---
 VDS.xcodeproj/project.pbxproj         |  4 +++
 VDS/Classes/ProxPropertyWrapper.swift | 47 +++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 VDS/Classes/ProxPropertyWrapper.swift

diff --git a/VDS.xcodeproj/project.pbxproj b/VDS.xcodeproj/project.pbxproj
index 326e6999..46e33dda 100644
--- a/VDS.xcodeproj/project.pbxproj
+++ b/VDS.xcodeproj/project.pbxproj
@@ -40,6 +40,7 @@
 		EA3362432892EFF20071C351 /* VDSLabelModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA3362422892EFF20071C351 /* VDSLabelModel.swift */; };
 		EA3362452892F9130071C351 /* Labelable.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA3362442892F9130071C351 /* Labelable.swift */; };
 		EA33624728931B050071C351 /* Initable.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA33624628931B050071C351 /* Initable.swift */; };
+		EA3C3B4C2894823E000CA526 /* ProxPropertyWrapper.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA3C3B4B2894823E000CA526 /* ProxPropertyWrapper.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -87,6 +88,7 @@
 		EA3362422892EFF20071C351 /* VDSLabelModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VDSLabelModel.swift; sourceTree = "<group>"; };
 		EA3362442892F9130071C351 /* Labelable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Labelable.swift; sourceTree = "<group>"; };
 		EA33624628931B050071C351 /* Initable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Initable.swift; sourceTree = "<group>"; };
+		EA3C3B4B2894823E000CA526 /* ProxPropertyWrapper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProxPropertyWrapper.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -213,6 +215,7 @@
 			isa = PBXGroup;
 			children = (
 				EA3361B5288B2A410071C351 /* VDSControl.swift */,
+				EA3C3B4B2894823E000CA526 /* ProxPropertyWrapper.swift */,
 			);
 			path = Classes;
 			sourceTree = "<group>";
@@ -387,6 +390,7 @@
 				EA3362432892EFF20071C351 /* VDSLabelModel.swift in Sources */,
 				EA33624728931B050071C351 /* Initable.swift in Sources */,
 				EA3361BD288B2C760071C351 /* TypeAlias.swift in Sources */,
+				EA3C3B4C2894823E000CA526 /* ProxPropertyWrapper.swift in Sources */,
 				EA3361AF288B26310071C351 /* FormFieldable.swift in Sources */,
 				EA3361B3288B265D0071C351 /* Changable.swift in Sources */,
 				EA336171288B19200071C351 /* VDS.docc in Sources */,
diff --git a/VDS/Classes/ProxPropertyWrapper.swift b/VDS/Classes/ProxPropertyWrapper.swift
new file mode 100644
index 00000000..17784723
--- /dev/null
+++ b/VDS/Classes/ProxPropertyWrapper.swift
@@ -0,0 +1,47 @@
+//
+//  ProxPropertyWrapper.swift
+//  VDS
+//
+//  Created by Matt Bruce on 7/29/22.
+//
+
+import Foundation
+
+//https://gist.github.com/jegnux/4a9871220ef93016d92194ecf7ae8919#file-proxypropertywrapper-swift
+@propertyWrapper
+public struct AnyProxy<EnclosingSelf, Value> {
+    private let keyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>
+
+    public init(_ keyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>) {
+        self.keyPath = keyPath
+    }
+
+    @available(*, unavailable, message: "The wrapped value must be accessed from the enclosing instance property.")
+    public var wrappedValue: Value {
+        get { fatalError() }
+        set { fatalError() }
+    }
+
+    public static subscript(
+        _enclosingInstance observed: EnclosingSelf,
+        wrapped wrappedKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>,
+        storage storageKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Self>
+    ) -> Value {
+        get {
+            let storageValue = observed[keyPath: storageKeyPath]
+            let value = observed[keyPath: storageValue.keyPath]
+            return value
+        }
+        set {
+            let storageValue = observed[keyPath: storageKeyPath]
+            observed[keyPath: storageValue.keyPath] = newValue
+        }
+    }
+}
+
+// Kudos @johnsundell for this trick
+// https://swiftbysundell.com/articles/accessing-a-swift-property-wrappers-enclosing-instance/
+extension NSObject: ProxyContainer {}
+public protocol ProxyContainer {
+    typealias Proxy<T> = AnyProxy<Self, T>
+}