ClosureSet

ClosureSet.swift

import Foundation
import PlaygroundSupport

PlaygroundPage.current.needsIndefiniteExecution = true

final class ClosureSet<T> {
    private var closure: ((T) -> Void)?
    
    init () { }
    
    func set(_ closure: @escaping (T) -> Void) {
        self.closure = closure
    }
    
    func notify(_ value: T? = nil) {
        guard let closure = closure else {
            return
        }
        switch value {
            case .some(let value): closure(value)
            case .none: closure(() as! T)
        }
    }
}

final class Controller {
    
    private var viewModel: ViewModel
    
    init(viewModel: ViewModel) {
        self.viewModel = viewModel
    }
}

final class ViewModel {
    
    private var interactor: InteractorProtocol
    
    init(interactor: InteractorProtocol) {
        self.interactor = interactor
        
        interactor.didFire.set { [weak self] in
            print("didFire")
        }
        interactor.valueChanged.set { [weak self] value in
            print("value Changed \(value)")
        }
    }
}

protocol InteractorProtocol {
    var didFire: ClosureSet<Void> { get }
    var valueChanged: ClosureSet<Int> { get }
}


final class Interactor: InteractorProtocol {
    
    let didFire = ClosureSet<Void>()
    let valueChanged = ClosureSet<Int>()
    
    private var counter = 0
    
    init() {
        setupTimer()
    }
    func setupTimer() {
        Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(fireaway), userInfo: nil, repeats: true)
    }
    
    @objc func fireaway() {
        counter += 1
        didFire.notify()
        valueChanged.notify(counter)
    }
    
}

var interactor = Interactor()
let viewModel = ViewModel(interactor: interactor)
let controller = Controller(viewModel: viewModel)