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node_modules/react-native-screens/ios/gamma/split-view/RNSSplitViewScreenController.swift

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+import Foundation
+import UIKit
+
+/// @class RNSSplitViewScreenController
+/// @brief A UIViewController subclass that manages a SplitView column in a UISplitViewController.
+///
+/// Associated with a RNSSplitViewScreenComponentView, it handles layout synchronization with the
+/// Shadow Tree, emits React lifecycle events, and interacts with the SplitViewHost hierarchy.
+@objc
+public class RNSSplitViewScreenController: UIViewController {
+  let splitViewScreenComponentView: RNSSplitViewScreenComponentView
+
+  private var shadowStateProxy: RNSSplitViewScreenShadowStateProxy {
+    return splitViewScreenComponentView.shadowStateProxy()
+  }
+
+  private var reactEventEmitter: RNSSplitViewScreenComponentEventEmitter {
+    return splitViewScreenComponentView.reactEventEmitter()
+  }
+
+  @objc public required init(splitViewScreenComponentView: RNSSplitViewScreenComponentView) {
+    self.splitViewScreenComponentView = splitViewScreenComponentView
+    super.init(nibName: nil, bundle: nil)
+  }
+
+  required init?(coder aDecoder: NSCoder) {
+    return nil
+  }
+
+  ///
+  /// @brief Searching for the SplitViewHost controller
+  ///
+  /// It checks whether the parent controller is our host controller.
+  /// If we're outside the structure, e. g. for inspector represented as a modal,
+  /// we're searching for that controller using a reference that Screen keeps for Host component view.
+  ///
+  /// @return If found - a RNSSplitViewHostController instance, otherwise nil.
+  ///
+  func findSplitViewHostController() -> RNSSplitViewHostController? {
+    if let splitViewHostController = self.splitViewController as? RNSSplitViewHostController {
+      return splitViewHostController
+    }
+
+    if let splitViewHost = self.splitViewScreenComponentView.splitViewHost {
+      return splitViewHost.splitViewHostController
+    }
+
+    return nil
+  }
+
+  ///
+  /// @brief Determines if this controller is nested inside a SplitViewHost hierarchy.
+  ///
+  /// Used to differentiate between screens embedded in the native host and modal presentations.
+  ///
+  /// @return true if inside RNSSplitViewHostController, false otherwise.
+  ///
+  @objc
+  public func isInSplitViewHostSubtree() -> Bool {
+    return self.splitViewController is RNSSplitViewHostController
+  }
+
+  // MARK: Signals
+
+  @objc
+  public func setNeedsLifecycleStateUpdate() {
+    findSplitViewHostController()?.setNeedsUpdateOfChildViewControllers()
+  }
+
+  // MARK: Layout
+
+  @objc
+  public override func viewDidLayoutSubviews() {
+    super.viewDidLayoutSubviews()
+
+    updateShadowTreeState()
+  }
+
+  ///
+  /// @brief Handles frame layout changes and updates Shadow Tree accordingly.
+  ///
+  /// Requests for the ShadowNode updates through the shadow state proxy.
+  /// Differentiates cases when we're in the Host hierarchy to calculate frame relatively
+  /// to the Host view from the modal case where we're passing absolute layout metrics to the ShadowNode.
+  ///
+  private func updateShadowTreeState() {
+    // For modals, which are presented outside the SplitViewHost subtree (and RN hierarchy),
+    // we're attaching our touch handler and we don't need to apply any offset corrections,
+    // because it's positioned relatively to our RNSSplitViewScreenComponentView
+    if !isInSplitViewHostSubtree() {
+      shadowStateProxy.updateShadowState(ofComponent: splitViewScreenComponentView)
+      return
+    }
+
+    let ancestorView = findSplitViewHostController()?.view
+    assert(
+      ancestorView != nil,
+      "[RNScreens] Expected to find RNSSplitViewHost component for RNSSplitViewScreen component"
+    )
+
+    shadowStateProxy.updateShadowState(
+      ofComponent: splitViewScreenComponentView, inContextOfAncestorView: ancestorView)
+  }
+
+  ///
+  /// @brief Request ShadowNode state update when the SplitView screen frame origin has changed.
+  ///
+  /// @param splitViewController The UISplitViewController whose layout positioning changed, represented by RNSSplitViewHostController.
+  ///
+  func columnPositioningDidChangeIn(splitViewController: UISplitViewController) {
+    shadowStateProxy.updateShadowState(
+      ofComponent: splitViewScreenComponentView, inContextOfAncestorView: splitViewController.view
+    )
+  }
+
+  // MARK: Events
+
+  public override func viewWillAppear(_ animated: Bool) {
+    reactEventEmitter.emitOnWillAppear()
+  }
+
+  public override func viewDidAppear(_ animated: Bool) {
+    reactEventEmitter.emitOnDidAppear()
+  }
+
+  public override func viewWillDisappear(_ animated: Bool) {
+    reactEventEmitter.emitOnWillDisappear()
+  }
+
+  public override func viewDidDisappear(_ animated: Bool) {
+    reactEventEmitter.emitOnDidDisappear()
+  }
+}