ViewControllerLifecycleBehavior

import UIKit

protocol ViewControllerLifecycleBehavior {
    func afterLoading(_ viewController: UIViewController)

    func beforeAppearing(_ viewController: UIViewController)

    func afterAppearing(_ viewController: UIViewController)

    func beforeDisappearing(_ viewController: UIViewController)

    func afterDisappearing(_ viewController: UIViewController)

    func beforeLayingOutSubviews(_ viewController: UIViewController)

    func afterLayingOutSubviews(_ viewController: UIViewController)
}

extension ViewControllerLifecycleBehavior {
    func afterLoading(_ viewController: UIViewController) {}

    func beforeAppearing(_ viewController: UIViewController) {}

    func afterAppearing(_ viewController: UIViewController) {}

    func beforeDisappearing(_ viewController: UIViewController) {}

    func afterDisappearing(_ viewController: UIViewController) {}

    func beforeLayingOutSubviews(_ viewController: UIViewController) {}

    func afterLayingOutSubviews(_ viewController: UIViewController) {}
}

extension UIViewController {
    /*
     Add behaviors to be hooked into this view controller’s lifecycle.

     This method requires the view controller’s view to be loaded, so it’s best to call
     in `viewDidLoad` to avoid it being loaded prematurely.

     - parameter behaviors: Behaviors to be added.
     */
    func addBehaviors(behaviors: [ViewControllerLifecycleBehavior]) {
        let behaviorViewController = LifecycleBehaviorViewController(behaviors: behaviors)

        addChild(behaviorViewController)
        view.addSubview(behaviorViewController.view)
        behaviorViewController.didMove(toParent: self)
    }

    private final class LifecycleBehaviorViewController: UIViewController {
        private let behaviors: [ViewControllerLifecycleBehavior]

        // MARK: - Initialization

        init(behaviors: [ViewControllerLifecycleBehavior]) {
            self.behaviors = behaviors

            super.init(nibName: nil, bundle: nil)
        }

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

        // MARK: - UIViewController

        override func viewDidLoad() {
            super.viewDidLoad()

            view.isHidden = true

            applyBehaviors { behavior, viewController in
                behavior.afterLoading(viewController)
            }
        }

        override func viewWillAppear(_ animated: Bool) {
            super.viewWillAppear(animated)

            applyBehaviors { behavior, viewController in
                behavior.beforeAppearing(viewController)
            }
        }

        override func viewDidAppear(_ animated: Bool) {
            super.viewDidAppear(animated)

            applyBehaviors { behavior, viewController in
                behavior.afterAppearing(viewController)
            }
        }

        override func viewWillDisappear(_ animated: Bool) {
            super.viewWillDisappear(animated)

            applyBehaviors { behavior, viewController in
                behavior.beforeDisappearing(viewController)
            }
        }

        override func viewDidDisappear(_ animated: Bool) {
            super.viewDidDisappear(animated)

            applyBehaviors { behavior, viewController in
                behavior.afterDisappearing(viewController)
            }
        }

        override func viewWillLayoutSubviews() {
            super.viewWillLayoutSubviews()

            applyBehaviors { behavior, viewController in
                behavior.beforeLayingOutSubviews(viewController)
            }
        }

        override func viewDidLayoutSubviews() {
            super.viewDidLayoutSubviews()

            applyBehaviors { behavior, viewController in
                behavior.afterLayingOutSubviews(viewController)
            }
        }

        // MARK: - Private

        private func applyBehaviors(body: (_ behavior: ViewControllerLifecycleBehavior, _ viewController: UIViewController) -> ()) {
            guard let parentViewController = parent else { return }

            for behavior in behaviors {
                body(behavior, parentViewController)
            }
        }
    }
}

typealias BehaviorClosure = (_ viewController: UIViewController) -> ()

// MARK: - ViewControllerLifecycle

enum ViewControllerLifecycle : CaseIterable {
    typealias AllCases = [ViewControllerLifecycle]
    
    case afterLoading(BehaviorClosure?)
    case afterAppearing(BehaviorClosure?)
    case beforeAppearing(BehaviorClosure?)
    case beforeDisappearing(BehaviorClosure?)
    case afterDisappearing(BehaviorClosure?)
    case beforeLayingOutSubviews(BehaviorClosure?)
    case afterLayingOutSubviews(BehaviorClosure?)
    
    static var allCases: [ViewControllerLifecycle] {
        return [afterLoading(nil),
                beforeAppearing(nil),
                beforeDisappearing(nil),
                beforeLayingOutSubviews(nil),
                afterLayingOutSubviews(nil)]
    }
}

// MARK: - createAnonimousBehavior

func createAnonimousBehavior(with lifecycle: [ViewControllerLifecycle]) -> ViewControllerLifecycleBehavior {

    class AnonimousBehavior: ViewControllerLifecycleBehavior {
        private var lifeCycle: [ViewControllerLifecycle]

        init(lifeCycle:[ViewControllerLifecycle]) {
            self.lifeCycle = lifeCycle
        }

        func afterLoading(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .afterLoading(let closure) = $0 else { return }
                closure?(viewController)
            }
        }

        func afterAppearing(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .afterAppearing(let closure) = $0 else { return }
                closure?(viewController)
            }
        }
        
        func beforeAppearing(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .beforeAppearing(let closure) = $0 else { return }
                closure?(viewController)
            }
        }

        func beforeDisappearing(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .beforeDisappearing(let closure) = $0 else { return }
                closure?(viewController)
            }
        }

        func afterDisappearing(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .afterDisappearing(let closure) = $0 else { return }
                closure?(viewController)
            }
        }

        func beforeLayingOutSubviews(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .beforeLayingOutSubviews(let closure) = $0 else { return }
                closure?(viewController)
            }
        }

        func afterLayingOutSubviews(_ viewController: UIViewController) {
            lifeCycle.forEach {
                guard case .afterLayingOutSubviews(let closure) = $0 else { return }
                closure?(viewController)
            }
        }
    }

    let behavior = AnonimousBehavior(lifeCycle: ViewControllerLifecycle.allCases)
    return behavior
}