AndreyPanov

var headerLabel: (UILabel) -> () = { control in
  control.font = .systemFont(ofSize: 20)
  control.textColor = .red
}
var bodyLabel: (UILabel) -> () = { control in
  control.font = .systemFont(ofSize: 15)
  control.textColor = .darkGray
}
var loginTextField: (UITextField) -> () = { control in
  control.font = .systemFont(ofSize: 15)

AndreyPanov

enum Guide {
  case headerLabel((UILabel) -> ())
  case bodyLabel((UILabel) -> ())
  case loginTextField((UITextField) -> ())
  
  func identifier() -> String {
    switch self {
    case .headerLabel: return "header"
    case .bodyLabel: return "body"
    case .loginTextField: return "login"

AndreyPanov

func guide() -> [Guide] {
  return [
    .headerLabel(headerLabel),
    .bodyLabel(bodyLabel),
    .loginTextField(loginTextField)
  ]
}

AndreyPanov

func perform<T>(with identifier: String, closure: (T) -> Void) {
  Mirror(reflecting: self).children.forEach { property in
    guard
      property.label?.contain(identifier) == true,
      let value = property.value as? T
      else { return }
    //run closure
    closure(value)
  }
}

AndreyPanov

func applyStyle() {
  StyleBuilder()
    .guide()
    .forEach { setStyle(with: $0) }
}

private func setStyle(with guide: Guide) {
  switch guide {
    case .headerLabel(let closure),
         .bodyLabel(let closure):

AndreyPanov

final class Repository {
  private let dataProdider: DataProvider
  init(dataProdider: DataProvider = .init()) {
    self.dataProdider = dataProdider
  }
  
  func getItem(onSuccess: @escaping (Item)->(), onError: @escaping (Error)->()) {
    //background async request
    dataProvider.request.items { [weak self] data, error in
      if let item = ItemBuilder(with: data) {

AndreyPanov

func onViewLoaded() {
  view?.showLoadingIndicator()
  repository.getItem(
    onSuccess: { [weak self] item in
      self?.view?.hideLoadingIndicator()
      print(item.description)
    },
    onError: { [weak self] error in
      self?.view?.hideLoadingIndicator()
      print(error.localizedDescription)

AndreyPanov

func onViewLoaded() {
  view?.showLoadingIndicator()
  repository
    .before({ [weak self] in self?.view?.hideLoadingIndicator() })
    .getItem(
      onSuccess: { [weak self] item in
        print(item.description)
      },
      onError: { [weak self] error in
        print(error.localizedDescription)

AndreyPanov

protocol Chainable: class {
  var before: (()->())? { get set }
  
  func before(_ callback: @escaping ()->()) -> Self
  func invoke()
}

extension Chainable {
  
  @discardableResult

AndreyPanov

final class Repository: Chainable {
  var before: (()->())?
  
  private let dataProdider: DataProvider
  init(dataProdider: DataProvider = .init()) {
    self.dataProdider = dataProdider
  }
  
  func getItem(onSuccess: @escaping (Item)->(), onError: @escaping (Error)->()) {
    //background async request