MVVM+Coordinator Architecture

mvvmc.swift

import UIKit

struct FrontScreenViewmodel {
    var hello = "there"
}

// Builds the ViewControllers, and injects the ViewModels
class Factory {
    
    let viewModelFactory = ViewModelFactory()
    let mainStack: UINavigationController
    
    func createFrontScreen(withStack: UINavigationController? = nil) -> UIViewController {
        // create a new Coordinator, pass in our factory
        let coor = FrontScreenCoordinator(withStack: withStack ?? mainStack, factory: self)
        let viewmodel = viewModelFactory.FrontScreenViewmodel()
        return FrontScreenViewController(withViewModel: viewmodel, coordinator: coor)
    }
    
    init(withStack: UINavigationController) {
        mainStack = withStack
    }
}

// Handles Core Data, Networing, etc assembly of documentModel into ViewModel
class ViewModelFactory {
    func FrontScreenViewmodel() -> FrontScreenViewmodel {
        // pass in other things like interactors, etc.
        return FrontScreenViewmodel()
    }
}

class FrontScreenCoordinator {
    
    // encapsulates the Routes this VC can trigger. Each VC has unique coordinator.
    func gotoNext() {}
    func goBack() {}
    func showStore(withId: Int) {
        let vc = factory.createFrontScreen()
        stack.pushViewController(vc, animated: true)
    }
    
    private let factory: Factory
    private let stack: UINavigationController
    
    init(withStack: UINavigationController, factory: Factory) {
        self.stack = withStack
        self.factory = factory
    }
}

class FrontScreenViewController: UIViewController {
    
    private let coordinator: FrontScreenCoordinator
    private let viewModel: FrontScreenViewmodel
    
    init(withViewModel: FrontScreenViewmodel, coordinator: FrontScreenCoordinator) {
        
        self.coordinator = coordinator
        self.viewModel = withViewModel
        super.init()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}