Whole navigation implementation: Navigation + Navigator

whole_navigation.swift

import UIKit

enum Navigation {
    case section(Section)
    case modal(Screen)
    case push(Screen)
}

enum Section: Int {
    case home
    case messages
    case notifications
    case profile
}

struct Screen {
    let viewController: () -> UIViewController
}

extension Screen {
    static func offer(with id: String) -> Self {
        return .init() { OfferViewController(id: id) }
    }
}

extension Screen {
    static func job(with id: String) -> Self {
        return .init() { JobViewController(id: id) }
    }
}

extension Screen {
    static func document(with url: URL) -> Self {
        return .init() { DocumentViewController(url: url) }
    }
}

class Navigator {
    var tabBarController: UITabBarController!
    var navigationController: UINavigationController!

    func handle(navigation: Navigation, animated: Bool = true) {
        switch navigation {
        case .section(let section):
            tabBarController.selectedIndex = section.rawValue
        case .modal(let screen):
            tabBarController.present(screen.viewController(), animated: animated)
        case .push(let screen):
            navigationController.pushViewController(screen.viewController(), animated: animated)
        }
    }
}

let navigator = Navigator()

navigator.handle(navigation: .section(.home))
navigator.handle(navigation: .modal(.offer(with: "1")))
navigator.handle(navigation: .push(.job(with: "1")))

class OfferViewController: UIViewController {
    private let id: String

    init(id: String) {
        self.id = id
        super.init(nibName: nil, bundle: nil)
    }

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

class JobViewController: UIViewController {
    private let id: String

    init(id: String) {
        self.id = id
        super.init(nibName: nil, bundle: nil)
    }

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

class DocumentViewController: UIViewController {
    private let url: URL

    init(url: URL) {
        self.url = url
        super.init(nibName: nil, bundle: nil)
    }

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