Untitled

import SwiftUI

final class Flow: UIHostingController<V> {

    init() {
        let viewModel = VM(router: self)
        let view = V(viewModel: viewModel)
        super.init(rootView: view)
    }

    @MainActor required dynamic init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

extension Flow: Routing {
    func routeToBlueBox() {
        navigationController?.pushViewController(BlueCoordinator(), animated: true)
    }

    func routeToRedBox() {
        navigationController?.present(RedCoordinator(), animated: true)
    }
}

protocol Routing: AnyObject {
    func routeToBlueBox()
    func routeToRedBox()
}

struct V: View {

    @StateObject var viewModel: VM

    var body: some View {
        VStack {
            Button(action: viewModel.handleActionA) {
                Text("Show red")
            },
            Button(action: viewModel.handleActionA) {
                Text("Show blue")
            }
        }
    }
}


final class VM: ObservableObject {

    weak var router: Routing?

    init(router: Routing?) {
        self.router = router
    }

    func handleActionA() {
        router?.routeToRedBox()
    }

    func handleActionB() {
        router?.routeToBlueBox()
    }
}