import UIKit

class ShowTransparentViewController: UIViewController {
	
	override func viewDidLoad() {
		super.viewDidLoad()
		
		view.backgroundColor = .white
		
		var cfg = UIButton.Configuration.filled()
		cfg.title = "Show Transparent VC"
		
		let btn = UIButton(configuration: cfg, primaryAction: UIAction() { _ in
			self.presentTransparentVC()
		})

		btn.translatesAutoresizingMaskIntoConstraints = false
		view.addSubview(btn)
		
		let g = view.safeAreaLayoutGuide
		
		NSLayoutConstraint.activate([
			btn.topAnchor.constraint(equalTo: g.topAnchor, constant: 60.0),
			btn.centerXAnchor.constraint(equalTo: view.centerXAnchor),
		])
	}
	
	func presentTransparentVC() {
		let vc = TransparentViewController()
		vc.modalPresentationStyle = .overFullScreen
		
		// personal choice... I find .crossDissolve nicer for full-screen modals
		vc.modalTransitionStyle = .crossDissolve
		
		present(vc, animated: true, completion: nil)
	}
}

class TransparentViewController: UIViewController {
	
	override func viewDidLoad() {
		super.viewDidLoad()
		
		// Set background color to black with 50% alpa
		view.backgroundColor = UIColor.black.withAlphaComponent(0.5)

		// "bottom" view with rounded corners
		let bottomView = UIView()
		bottomView.backgroundColor = .init(red: 0.95, green: 0.95, blue: 0.975, alpha: 1.0)
		bottomView.layer.cornerRadius = 32.0
		
		// "X" close button
		var cfg = UIButton.Configuration.plain()
		cfg.title = "X"

		let btn = UIButton(configuration: cfg, primaryAction: UIAction() { _ in
			self.dismiss(animated: true)
		})
		
		btn.translatesAutoresizingMaskIntoConstraints = false
		bottomView.addSubview(btn)

		bottomView.translatesAutoresizingMaskIntoConstraints = false
		view.addSubview(bottomView)
		
		let g = view.safeAreaLayoutGuide

		NSLayoutConstraint.activate([
			
			bottomView.bottomAnchor.constraint(equalTo: g.bottomAnchor, constant: 40.0),
			bottomView.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 0.0),
			bottomView.trailingAnchor.constraint(equalTo: g.trailingAnchor, constant: 0.0),
			bottomView.heightAnchor.constraint(equalToConstant: 280.0),
			
			btn.topAnchor.constraint(equalTo: bottomView.topAnchor, constant: 20.0),
			btn.trailingAnchor.constraint(equalTo: bottomView.trailingAnchor, constant: -20.0),
			
		])
		
		
	}

}