⭐️ Impl: ModalSheetPresentationStateMachine

ios/Temp/ModalSheetPresentationStateMachine.swift

@@ -0,0 +1,110 @@
+//
+//  ModalSheetPresentationStateMachine.swift
+//  react-native-ios-modal
+//
+//  Created by Dominic Go on 9/27/24.
+//
+
+import UIKit
+import DGSwiftUtilities
+
+
+public class ModalSheetPresentationStateMachine {
+
+  public var prevState: ModalSheetState?;
+  public var currentState: ModalSheetState = .dismissed;
+
+  public var didPresent = false;
+  public var didDismissAfterPresented = false;
+
+  public var eventDelegates:
+    MulticastDelegate<ModalSheetStateEventNotifiable> = .init();
+
+  public func setStateExplicit(nextState: ModalSheetState){
+    let prevState = self.prevState;
+    let currentState = self.currentState;
+
+    self.prevState = self.currentState;
+    self.currentState = nextState;
+
+    switch (prevState, currentState, nextState) {
+      case (_, let currentState, let nextState)
+        where !currentState.isPresented && nextState.isPresented:
+
+        self.didPresent = true;
+
+      case (_, let currentState, let nextState) where
+        !currentState.isPresented && nextState.isPresented:
+
+        self.didDismissAfterPresented = true;
+
+      default:
+        break;
+    };
+  };
+
+  public func setState(nextState: ModalSheetState){
+    switch (self.prevState, self.currentState, nextState) {
+
+      default:
+        break;
+    };
+
+    self.setStateExplicit(nextState: nextState);
+  };
+
+  public func reset(){
+    self.prevState = nil;
+    self.currentState = .dismissed;
+
+    self.didPresent = false;
+    self.didDismissAfterPresented = false;
+  };
+};
+
+extension ModalSheetPresentationStateMachine: ViewControllerLifecycleNotifiable {
+
+  public func notifyOnViewDidLoad(sender: UIViewController) {
+    // no-op
+  };
+
+  public func notifyOnViewWillAppear(
+    sender: UIViewController,
+    isAnimated: Bool
+  ) {
+
+    self.setState(nextState: .presenting);
+  };
+
+  public func notifyOnViewIsAppearing(
+    sender: UIViewController,
+    isAnimated: Bool
+  ) {
+
+    self.setState(nextState: .presenting);
+  };
+
+  public func notifyOnViewDidAppear(
+    sender: UIViewController,
+    isAnimated: Bool
+  ) {
+
+    self.setState(nextState: .presented);
+  };
+
+  public func notifyOnViewWillDisappear(
+    sender: UIViewController,
+    isAnimated: Bool
+  ) {
+
+    self.setState(nextState: .dismissing);
+  };
+
+  public func notifyOnViewDidDisappear(
+    sender: UIViewController,
+    isAnimated: Bool
+  ) {
+
+    self.setState(nextState: .dismissed);
+  };
+};

ios/Temp/ModalSheetViewControllerLifecycleNotifier.swift

@@ -28,6 +28,9 @@ open class ModalSheetViewControllerLifecycleNotifier: ViewControllerLifecycleNot
 
   public weak var sheetGesture: UIPanGestureRecognizer?;
   public weak var sheetDropShadowView: UIView?;
+
+  public var sheetPresentationStateMachine:
+    ModalSheetPresentationStateMachine = .init();
 
   // MARK: - View Controller Lifecycle
   // ---------------------------------
@@ -56,6 +59,8 @@ open class ModalSheetViewControllerLifecycleNotifier: ViewControllerLifecycleNot
       self.presentationControllerDelegateProxy = self;
     };
 
+    self.lifecycleEventDelegates.add(self.sheetPresentationStateMachine);
+
     presentationController.delegate = self;
     self._didSetup = true;
   };