Added multilevel window support for stacked presentation

Source/Infra/EKWindow.swift

@@ -12,7 +12,7 @@ class EKWindow: UIWindow {
 
     var isAbleToReceiveTouches = false
 
-    init(with rootVC: UIViewController) {
+    init(with rootVC: UIViewController, level: UIWindow.Level) {
         if #available(iOS 13.0, *) {
             // TODO: Patched to support SwiftUI out of the box but should require attendance
             if let scene = UIApplication.shared.connectedScenes.filter({$0.activationState == .foregroundActive}).first as? UIWindowScene {
@@ -23,6 +23,7 @@ class EKWindow: UIWindow {
         } else {
             super.init(frame: UIScreen.main.bounds)
         }
+        windowLevel = level
         backgroundColor = .clear
         rootViewController = rootVC
         accessibilityViewIsModal = true
@@ -37,7 +38,7 @@ class EKWindow: UIWindow {
             return super.hitTest(point, with: event)
         }
 
-        guard let rootVC = EKWindowProvider.shared.rootVC else {
+        guard let rootVC = EKWindowProvider.provider(for: windowLevel).rootVC else {
             return nil
         }
 

Source/Infra/EKWindowProvider.swift

@@ -13,15 +13,68 @@ final class EKWindowProvider: EntryPresenterDelegate {
     /** The artificial safe area insets */
     static var safeAreaInsets: UIEdgeInsets {
         if #available(iOS 11.0, *) {
-            return EKWindowProvider.shared.entryWindow?.rootViewController?.view?.safeAreaInsets ?? UIApplication.shared.keyWindow?.rootViewController?.view.safeAreaInsets ?? .zero
+            return EKWindowProvider.provider(for: .normal).entryWindow?.rootViewController?.view?.safeAreaInsets ?? UIApplication.shared.keyWindow?.rootViewController?.view.safeAreaInsets ?? .zero
         } else {
             let statusBarMaxY = UIApplication.shared.statusBarFrame.maxY
             return UIEdgeInsets(top: statusBarMaxY, left: 0, bottom: 10, right: 0)
         }
     }
 
+    private static var providers: [UIWindow.Level: EKWindowProvider] = [:]
     /** Single access point */
-    static let shared = EKWindowProvider()
+    static func provider(for level: UIWindow.Level) -> EKWindowProvider {
+        if let provider = providers[level] {
+            return provider
+        } else {
+            let provider = EKWindowProvider(level: level)
+            providers[level] = provider
+            return provider
+        }
+    }
+
+    static var topMostProvider: EKWindowProvider? {
+        if let topMostLevel = providers.keys.sorted(by: { $0 > $1 }).first {
+            return provider(for: topMostLevel)
+        }
+        return nil
+    }
+
+    static func isCurrentlyDisplaying(entryNamed name: String? = nil) -> Bool {
+        for provider in providers.values
+        where provider.isCurrentlyDisplaying(entryNamed: name) {
+            return true
+        }
+        return false
+    }
+
+    static func queueContains(entryNamed name: String? = nil) -> Bool {
+        for provider in providers.values
+        where provider.queueContains(entryNamed: name) {
+            return true
+        }
+        return false
+    }
+
+    static func dismiss(_ descriptor: SwiftEntryKit.EntryDismissalDescriptor, with completion: SwiftEntryKit.DismissCompletionHandler? = nil) {
+
+        switch descriptor {
+        case .displayed:
+            topMostProvider?.rootVC?.animateOutLastEntry(completionHandler: completion)
+        default:
+            let dispatchGroup = DispatchGroup()
+            for provider in providers.values {
+                dispatchGroup.enter()
+                provider.dismiss(descriptor) {
+                    dispatchGroup.leave()
+                }
+            }
+            dispatchGroup.notify(queue: .main, execute: completion ?? {})
+        }
+    }
+
+    static func layoutIfNeeded() {
+        providers.values.forEach { $0.layoutIfNeeded() }
+    }
 
     /** Current entry window */
     var entryWindow: EKWindow!
@@ -41,9 +94,13 @@ final class EKWindowProvider: EntryPresenterDelegate {
     private let entryQueue = EKAttributes.Precedence.QueueingHeuristic.value.heuristic
 
     private weak var entryView: EKEntryView!
+
+    private let windowLevel: UIWindow.Level
 
     /** Cannot be instantiated, customized, inherited */
-    private init() {}
+    private init(level: UIWindow.Level) {
+        windowLevel = level
+    }
 
     var isResponsiveToTouches: Bool {
         set {
@@ -64,7 +121,6 @@ final class EKWindowProvider: EntryPresenterDelegate {
         }
         entryVC.setStatusBarStyle(for: attributes)
 
-        entryWindow.windowLevel = attributes.windowLevel.value
         if presentInsideKeyWindow {
             entryWindow.makeKeyAndVisible()
         } else {
@@ -79,7 +135,7 @@ final class EKWindowProvider: EntryPresenterDelegate {
         let entryVC: EKRootViewController
         if entryWindow == nil {
             entryVC = EKRootViewController(with: self)
-            entryWindow = EKWindow(with: entryVC)
+            entryWindow = EKWindow(with: entryVC, level: windowLevel)
             mainRollbackWindow = UIApplication.shared.keyWindow
         } else {
             entryVC = rootVC!
@@ -151,6 +207,9 @@ final class EKWindowProvider: EntryPresenterDelegate {
 
     /** Clear all entries immediately and display to the rollback window */
     func displayRollbackWindow() {
+        defer {
+            EKWindowProvider.providers.removeValue(forKey: windowLevel)
+        }
         if #available(iOS 13.0, *) {
             entryWindow.windowScene = nil
         }

Source/SwiftEntryKit.swift

@@ -53,8 +53,8 @@ public final class SwiftEntryKit {
      no entry is currently displayed.
      This can be used
      */
-    public class var window: UIWindow? {
-        return EKWindowProvider.shared.entryWindow
+    public class func window(for level: UIWindow.Level) -> UIWindow? {
+        return EKWindowProvider.provider(for: level).entryWindow
     }
 
     /**
@@ -74,7 +74,7 @@ public final class SwiftEntryKit {
      - parameter name: The name of the entry. Its default value is *nil*.
      */
     public class func isCurrentlyDisplaying(entryNamed name: String? = nil) -> Bool {
-        return EKWindowProvider.shared.isCurrentlyDisplaying(entryNamed: name)
+        return EKWindowProvider.isCurrentlyDisplaying(entryNamed: name)
     }
 
     /**
@@ -93,7 +93,7 @@ public final class SwiftEntryKit {
      - parameter name: The name of the entry. Its default value is *nil*.
      */
     public class func queueContains(entryNamed name: String? = nil) -> Bool {
-        return EKWindowProvider.shared.queueContains(entryNamed: name)
+        return EKWindowProvider.queueContains(entryNamed: name)
     }
 
     /**
@@ -107,7 +107,8 @@ public final class SwiftEntryKit {
      */
     public class func display(entry view: UIView, using attributes: EKAttributes, presentInsideKeyWindow: Bool = false, rollbackWindow: RollbackWindow = .main) {
         DispatchQueue.main.async {
-            EKWindowProvider.shared.display(view: view, using: attributes, presentInsideKeyWindow: presentInsideKeyWindow, rollbackWindow: rollbackWindow)
+            EKWindowProvider.provider(for: attributes.windowLevel.value)
+                .display(view: view, using: attributes, presentInsideKeyWindow: presentInsideKeyWindow, rollbackWindow: rollbackWindow)
         }
     }
 
@@ -122,7 +123,8 @@ public final class SwiftEntryKit {
      */
     public class func display(entry viewController: UIViewController, using attributes: EKAttributes, presentInsideKeyWindow: Bool = false, rollbackWindow: RollbackWindow = .main) {
         DispatchQueue.main.async {
-            EKWindowProvider.shared.display(viewController: viewController, using: attributes, presentInsideKeyWindow: presentInsideKeyWindow, rollbackWindow: rollbackWindow)
+            EKWindowProvider.provider(for: attributes.windowLevel.value)
+                .display(viewController: viewController, using: attributes, presentInsideKeyWindow: presentInsideKeyWindow, rollbackWindow: rollbackWindow)
         }
     }
 
@@ -135,7 +137,7 @@ public final class SwiftEntryKit {
      */
     public class func transform(to view: UIView) {
         DispatchQueue.main.async {
-            EKWindowProvider.shared.transform(to: view)
+            EKWindowProvider.topMostProvider?.transform(to: view)
         }
     }
 
@@ -148,7 +150,7 @@ public final class SwiftEntryKit {
      */
     public class func dismiss(_ descriptor: EntryDismissalDescriptor = .displayed, with completion: DismissCompletionHandler? = nil) {
         DispatchQueue.main.async {
-            EKWindowProvider.shared.dismiss(descriptor, with: completion)
+            EKWindowProvider.dismiss(descriptor, with: completion)
         }
     }
 
@@ -160,10 +162,10 @@ public final class SwiftEntryKit {
      */
     public class func layoutIfNeeded() {
         if Thread.isMainThread {
-            EKWindowProvider.shared.layoutIfNeeded()
+            EKWindowProvider.layoutIfNeeded()
         } else {
             DispatchQueue.main.async {
-                EKWindowProvider.shared.layoutIfNeeded()
+                EKWindowProvider.layoutIfNeeded()
             }
         }
     }