Example Donuts MVP architecture

donutsMVP.swift

class DonutsViewController: UIViewController, DonutsView {
  lazy let presenter = { DonutsPresenter(view: self) }()

  override func showLoading() {
  
  }

  override func showNoBringers() {
  
  }

  override func showBringers(users: [User]) {
  
  }
}

class DonutsPresenter {
  let view: DonutsView
  let donutsRepo: DonutsRepo
  
  init(view: DonutsView, repo: DonutsRepo = DonutsRepo.shared) {
    self.view = view
  }

  func onBringingDonutsSelected() {
    view.showLoading(true)
    donutsRepo.postBringingDonuts()
      .subscribe(
        onNext: { users in
          self.updateView(users)
        },
        onError: { error in
          updateView([], error: error)
        }
      )
  }

  private func updateView(users: [User], error: Error? = nil) {
    view.showLoading(false)
    if users.isEmpty {
      view.showNoBringers()
    } else {
      view.showBringers(users)
      
    }
    if let error = error {
      view.showError(error)
    }
  }
}

protocol DonutsView {
  func showLoading(_ isLoading: Bool)
  func showBringers(bringers: [User])
  func showNoBringers()
}