AnonimousBehavior

import UIKit

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

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) {}
}

func createAnonimousBehavior(afterLoading: BehaviorClosure? = nil,
                           beforeAppearing: BehaviorClosure? = nil,
                           afterAppearing: BehaviorClosure? = nil,
                           beforeDisappearing: BehaviorClosure? = nil,
                           afterDisappearing: BehaviorClosure? = nil,
                           beforeLayingOutSubviews: BehaviorClosure? = nil,
                           afterLayingOutSubviews: BehaviorClosure? = nil) -> ViewControllerLifecycleBehavior {

    class AnonimousBehavior: ViewControllerLifecycleBehavior {
        private var afterLoadingClosure: BehaviorClosure?
        private var beforeAppearingClosure: BehaviorClosure?
        private var afterAppearingClosure: BehaviorClosure?
        private var beforeDisappearingClosure: BehaviorClosure?
        private var afterDisappearingClosure: BehaviorClosure?
        private var beforeLayingOutSubviewsClosure: BehaviorClosure?
        private var afterLayingOutSubviewsClosure: BehaviorClosure?

        init(afterLoading: BehaviorClosure? = nil,
             beforeAppearing: BehaviorClosure? = nil,
             afterAppearing: BehaviorClosure? = nil,
             beforeDisappearing: BehaviorClosure? = nil,
             afterDisappearing: BehaviorClosure? = nil,
             beforeLayingOutSubviews: BehaviorClosure? = nil,
             afterLayingOutSubviews: BehaviorClosure? = nil) {

            self.afterLoadingClosure = afterLoading
            self.beforeAppearingClosure = beforeAppearing
            self.afterAppearingClosure = afterAppearing
            self.beforeDisappearingClosure = beforeDisappearing
            self.afterDisappearingClosure = afterDisappearing
            self.beforeLayingOutSubviewsClosure = beforeLayingOutSubviews
            self.afterLayingOutSubviewsClosure = afterLayingOutSubviews
        }

        func afterLoading(_ viewController: UIViewController) {
            afterLoadingClosure?(viewController)
        }

        func beforeAppearing(_ viewController: UIViewController) {
            beforeAppearingClosure?(viewController)
        }

        func afterAppearing(_ viewController: UIViewController) {
            afterAppearingClosure?(viewController)
        }

        func beforeDisappearing(_ viewController: UIViewController) {
            beforeDisappearingClosure?(viewController)
        }

        func afterDisappearing(_ viewController: UIViewController) {
            afterDisappearingClosure?(viewController)
        }

        func beforeLayingOutSubviews(_ viewController: UIViewController) {
            beforeLayingOutSubviewsClosure?(viewController)
        }

        func afterLayingOutSubviews(_ viewController: UIViewController) {
            afterLayingOutSubviewsClosure?(viewController)
        }

    }

    let behavior = AnonimousBehavior(afterLoading: afterLoading,
                                     beforeAppearing: beforeAppearing,
                                     afterAppearing: afterAppearing,
                                     beforeDisappearing: beforeDisappearing,
                                     afterDisappearing: afterDisappearing,
                                     beforeLayingOutSubviews: beforeLayingOutSubviews,
                                     afterLayingOutSubviews: afterLayingOutSubviews)
    return behavior
}

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)
            }
        }
    }
}