How to tap into the NSWindowDelegate

NSWindowDelegateAdaptor.swift

import AppKit
import SwiftUI

//         .onCloseButton(self.$object.delegate, { _ in
//           self.object.presentConfirmCloseAlert = true
//           return false
//         })

class NSWindowDelegateAdaptor: NSObject, NSWindowDelegate {
  internal init(onWindowShouldClose: ((NSWindow) -> Bool)?) {
    self.onWindowShouldClose = onWindowShouldClose
  }

  let onWindowShouldClose: ((NSWindow) -> Bool)?

  func windowShouldClose(_ sender: NSWindow) -> Bool {
    onWindowShouldClose?(sender) ?? true
  }
}

private struct NSWindowDelegateAdaptorModifier: ViewModifier {
  @Binding var binding: NSWindowDelegate?
  // swiftlint:disable:next weak_delegate
  let delegate: NSWindowDelegate

  internal init(binding: Binding<NSWindowDelegate?>, delegate: @autoclosure () -> NSWindowDelegate) {
    self._binding = binding
    self.delegate = binding.wrappedValue ?? delegate()
    DispatchQueue.main.async { [self] in
      self.binding = self.delegate
    }
  }

  func body(content: Content) -> some View {
    content.nsWindowAdaptor { window in
      assert(!self.delegate.isEqual(window?.delegate))
      window?.delegate = delegate
    }
  }
}

extension View {
  func nsWindowDelegateAdaptor(_ binding: Binding<NSWindowDelegate?>, _ delegate: @autoclosure () -> NSWindowDelegate) -> some View {
    self.modifier(NSWindowDelegateAdaptorModifier(binding: binding, delegate: delegate()))
  }

  public func onCloseButton(_ delegate: Binding<NSWindowDelegate?>, _ closure: @escaping (NSWindow) -> Bool) -> some View {
    self.nsWindowDelegateAdaptor(delegate, NSWindowDelegateAdaptor(onWindowShouldClose: closure))
  }
}