TabBarController.swift

final class TabBarController: UITabBarController {
	
	override func viewDidLoad() {
		super.viewDidLoad()
		
		self.viewControllers = [
			TabBarItems.home.tabController,
			TabBarItems.search.tabController,
			TabBarItems.cart.tabController,
			TabBarItems.account.tabController
		]
		
		self.tabBar.isTranslucent = false
	}
}

extension TabBarController {
	enum TabBarItems {
		case home
		case search
		case cart
		case account
		
		var title: String {
			switch self {
				
			case .home:
				return "Home"
			case .search:
				return "Search"
			case .cart:
				return "Bag"
			case .account:
				return "Account"
			}
		}
		
		var tabController: UINavigationController {
			switch self {
			case .home:
				return createNavController(viewController: HomeController(), title: self.title, imageName: "home") //Assets.home.rawValue)
			case .search:
				return createNavController(viewController: UIViewController(), title: self.title, imageName: "search") //Assets.search.rawValue)
			case .cart:
				return createNavController(viewController: BagController(), title: self.title, imageName: "shoppingBag") //Assets.shoppingBag.rawValue)
			case .account:
				return createNavController(viewController: AccountController(), title: self.title, imageName: "account") //Assets.account.rawValue)
			}
		}
		
		private func createNavController(viewController: UIViewController, title: String, imageName: String) -> UINavigationController {
			let navController = UINavigationController(rootViewController: viewController)
			viewController.view.backgroundColor = .white
			navController.tabBarItem.title = title
			navController.tabBarItem.image = UIImage(named: imageName) // imageName.image
			return navController
			
		}
		
	}
}

class MyBaseViewController: UIViewController {
	
	let pushButton: UIButton = {
		let b = UIButton()
		b.translatesAutoresizingMaskIntoConstraints = false
		b.backgroundColor = .systemRed
		b.setTitle("Push", for: .normal)
		return b
	}()
	
	override func viewDidLoad() {
		super.viewDidLoad()
		print("load:", String(describing: self))
		
		let v = UILabel()
		v.translatesAutoresizingMaskIntoConstraints = false
		v.text = String(describing: self)
		v.backgroundColor = .cyan
		view.addSubview(v)
		NSLayoutConstraint.activate([
			v.centerXAnchor.constraint(equalTo: view.centerXAnchor),
			v.centerYAnchor.constraint(equalTo: view.centerYAnchor),
		])
		
		view.addSubview(pushButton)
		NSLayoutConstraint.activate([
			pushButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),
			pushButton.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20.0),
		])
		pushButton.addTarget(self, action: #selector(testPush), for: .touchUpInside)

	}
	
	override func viewWillAppear(_ animated: Bool) {
		super.viewWillAppear(animated)
		print("will:", String(describing: self))
	}
	
	override func viewDidAppear(_ animated: Bool) {
		super.viewDidAppear(animated)
		print("did:", String(describing: self))
	}
	
	@objc func testPush() -> Void {
		let vc = PushedController()
		self.navigationController?.pushViewController(vc, animated: true)
	}
	
}

class HomeController: MyBaseViewController {
	
}

class BagController: MyBaseViewController {
	
}

class AccountController: MyBaseViewController {
	
}

class PushedController: MyBaseViewController {
	
	override func viewDidLoad() {
		super.viewDidLoad()
		view.backgroundColor = .systemYellow
		pushButton.isHidden = true
	}
	
}