class BkgTableVC: UITableViewController {
	
	let bkgView = TVBkgView()
	
	override func viewDidLoad() {
		super.viewDidLoad()
		
		view.backgroundColor = .white
		
		tableView.register(UITableViewCell.self, forCellReuseIdentifier: "c")
		
		tableView.contentInset = UIEdgeInsets(top: 200, left: 0, bottom: 0, right: 0)
		
		tableView.backgroundView = bkgView
	}
	
	override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
		return 30
	}
	override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
		let c = tableView.dequeueReusableCell(withIdentifier: "c", for: indexPath)
		c.textLabel?.text = "\(indexPath)"
		return c
	}
	
}

class TVBkgView: UIView, UICollectionViewDataSource, UICollectionViewDelegate {
	
	let titleLabel: UILabel = {
		let v = UILabel()
		v.backgroundColor = .brown
		v.textColor = .yellow
		v.textAlignment = .center
		return v
	}()
	
	let infoLabel: UILabel = {
		let v = UILabel()
		v.backgroundColor = .brown
		v.textColor = .yellow
		v.textAlignment = .center
		return v
	}()

	var cView: UICollectionView!
	
	override init(frame: CGRect) {
		super.init(frame: frame)
		commonInit()
	}
	required init?(coder: NSCoder) {
		super.init(coder: coder)
		commonInit()
	}
	func commonInit() -> Void {
		backgroundColor = .orange
		
		let fl = UICollectionViewFlowLayout()
		fl.scrollDirection = .horizontal
		fl.itemSize = CGSize(width: 160, height: 80)
		
		cView = UICollectionView(frame: .zero, collectionViewLayout: fl)
		
		titleLabel.translatesAutoresizingMaskIntoConstraints = false
		cView.translatesAutoresizingMaskIntoConstraints = false
		infoLabel.translatesAutoresizingMaskIntoConstraints = false
		
		addSubview(titleLabel)
		addSubview(cView)
		addSubview(infoLabel)

		NSLayoutConstraint.activate([
			
			titleLabel.topAnchor.constraint(equalTo: topAnchor, constant: 44.0),
			titleLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 20.0),
			titleLabel.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -20.0),
			titleLabel.heightAnchor.constraint(equalToConstant: 28.0),

			cView.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 8.0),
			cView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 0.0),
			cView.trailingAnchor.constraint(equalTo: trailingAnchor, constant: 0.0),
			cView.heightAnchor.constraint(equalToConstant: 88.0),
			
			infoLabel.topAnchor.constraint(equalTo: cView.bottomAnchor, constant: 8.0),
			infoLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 20.0),
			infoLabel.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -20.0),
			infoLabel.heightAnchor.constraint(equalTo: titleLabel.heightAnchor),
			
		])
		
		titleLabel.text = "Background View"
		infoLabel.text = "Info"
		
		cView.dataSource = self
		cView.delegate = self
		cView.register(TVBkgCell.self, forCellWithReuseIdentifier: "c")
	}
	
	func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
		return 30
	}
	
	func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
		let c = collectionView.dequeueReusableCell(withReuseIdentifier: "c", for: indexPath) as! TVBkgCell
		c.label.text = "\(indexPath.item)"
		c.button.setTitle("Button \(indexPath.item)", for: [])
		c.callBack = { [weak self] str in
			guard let self = self else { return }
			self.infoLabel.text = "Tapped: \(str)"
		}
		return c
	}

}

class TVBkgCell: UICollectionViewCell {
	
	var callBack: ((String) -> ())?
	
	let label: UILabel = {
		let v = UILabel()
		v.backgroundColor = .yellow
		v.textAlignment = .center
		return v
	}()
	
	let button: UIButton = {
		let v = UIButton()
		v.backgroundColor = .red
		v.setTitleColor(.white, for: .normal)
		v.setTitleColor(.lightGray, for: .highlighted)
		return v
	}()
	
	override init(frame: CGRect) {
		super.init(frame: frame)
		commonInit()
	}
	required init?(coder: NSCoder) {
		super.init(coder: coder)
		commonInit()
	}
	func commonInit() -> Void {
		contentView.backgroundColor = .systemBlue
		
		label.translatesAutoresizingMaskIntoConstraints = false
		button.translatesAutoresizingMaskIntoConstraints = false
		contentView.addSubview(label)
		contentView.addSubview(button)
		let g = contentView.layoutMarginsGuide
		NSLayoutConstraint.activate([
			
			label.topAnchor.constraint(equalTo: g.topAnchor),
			label.leadingAnchor.constraint(equalTo: g.leadingAnchor),
			label.trailingAnchor.constraint(equalTo: g.trailingAnchor),
			
			button.topAnchor.constraint(greaterThanOrEqualTo: label.bottomAnchor, constant: 8.0),
			button.leadingAnchor.constraint(equalTo: g.leadingAnchor),
			button.trailingAnchor.constraint(equalTo: g.trailingAnchor),
			button.bottomAnchor.constraint(equalTo: g.bottomAnchor),
			
		])
		
		button.addTarget(self, action: #selector(btnTap(_:)), for: .touchUpInside)
	}
	
	@objc func btnTap(_ sender: UIButton) {
		if let t = sender.currentTitle {
			callBack?(t)
		}
	}
	
}