AppTabBarController.swift

import UIKit

class AppTabBarController: UITabBarController, UITabBarControllerDelegate, WalkthroughViewControllerDelegate {
    var window: UIWindow?

    struct Constants {
        static let reuseIdentifier = String(describing: AppTabBarController.self)
        static let storyboardName = "Documents"
    }
    
    static func buildViewController() -> AppTabBarController {
        let controller = UIStoryboard(name: Constants.storyboardName,
                                      bundle: .main).instantiateViewController(withIdentifier: Constants.reuseIdentifier)
        return controller as! AppTabBarController
    }
    
    private var observation: NSKeyValueObservation?
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    deinit {
        observation = nil
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        window = UIWindow(frame: UIScreen.main.bounds)
        self.delegate = self
        
        observation = observe(\.tabBar.semanticContentAttribute) { value, change in
            self.reloadLocalization()
        }
        
        setupUI()
    }
    
    private func setupUI() {
        
        tabBar.items?[0].title = .fileManager.localized
        tabBar.items?[2].title = .studio.localized
        
        tabBar.items?[0].image = .folderOpen
        tabBar.items?[2].image = .gallery
    }
    
    private func reloadLocalization() {
        tabBar.items?[0].title = .fileManager.localized
        tabBar.items?[2].title = .studio.localized
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        if UserDefaults.standard.showWalktroughAtLaunch {
            perform(#selector(showWalkTrough), with: self, afterDelay: 0.88)
        }
    }
    
    let walkthroughs = [
        WalkthroughModel(title: "Quick Overview",
                         subtitle: "Quickly visualize important business metrics. The overview in the home tab shows the most important metrics to monitor how your business is doing in real time.",
                         icon: "analytics-icon"),
        WalkthroughModel(title: "Analytics",
                         subtitle: "Dive deep into charts to extract valuable insights and come up with data driven product initiatives, to boost the success of your business.",
                         icon: "bars-icon"),
        WalkthroughModel(title: "Dashboard Feeds",
                         subtitle: "View your sales feed, orders, customers, products and employees.",
                         icon: "activity-feed-icon"),
        WalkthroughModel(title: "Get Notified",