class MyCell: UICollectionViewCell {
	static let reuseIdentifier: String = "c"
}

class FullScreenCollVC: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
	
	var pageCollectionView: UICollectionView!
	
	let colors: [UIColor] = [
		.cyan, .yellow, .systemGreen, .systemBlue,
	]
	
	override func viewDidLoad() {
		super.viewDidLoad()
		view.backgroundColor = .red
		setupPageCollectionView()
	}
	private func setupPageCollectionView() {
		
		let flowLayout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
		flowLayout.scrollDirection = .horizontal
		flowLayout.minimumInteritemSpacing = 0
		flowLayout.minimumLineSpacing = 0
		flowLayout.sectionInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
		
		self.view.backgroundColor = .red
		
		pageCollectionView = UICollectionView(frame: .zero, collectionViewLayout: flowLayout)
		pageCollectionView.register(MyCell.self, forCellWithReuseIdentifier: MyCell.reuseIdentifier)
		pageCollectionView.delegate = self
		pageCollectionView.dataSource = self
		pageCollectionView.decelerationRate = .fast
		pageCollectionView.translatesAutoresizingMaskIntoConstraints = false
		
		pageCollectionView.backgroundColor = .blue
		self.view.addSubview(pageCollectionView)
		NSLayoutConstraint.activate([
			pageCollectionView.topAnchor.constraint(equalTo: self.view.topAnchor),
			pageCollectionView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
			pageCollectionView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
			pageCollectionView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor)
		])
		
	}
	func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
		print(indexPath.item, collectionView.bounds.size)
		return collectionView.bounds.size
	}
	func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
		return 5
	}
	func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
		let c = collectionView.dequeueReusableCell(withReuseIdentifier: MyCell.reuseIdentifier, for: indexPath) as! MyCell
		c.contentView.backgroundColor = colors[indexPath.item % colors.count]
		return c
	}
	
}