let stackView = StackFlowView() // StackFlowView(frame: ...)
stackView.delegate = self

view.addSubview(stackView)

/* — Optional constraints — */

([
	NSLayoutConstraint(item: stackView, attribute: .top, relatedBy: .equal, toItem: view, attribute: .top, multiplier: 1.0, constant: 0),
	NSLayoutConstraint(item: stackView, attribute: .bottom, relatedBy: .equal, toItem: view, attribute: .bottom, multiplier: 1.0, constant: 0),
	NSLayoutConstraint(item: stackView, attribute: .leading, relatedBy: .equal, toItem: view, attribute: .leading, multiplier: 1.0, constant: 0),
	NSLayoutConstraint(item: stackView, attribute: .trailing, relatedBy: .equal, toItem: view, attribute: .trailing, multiplier: 1.0, constant: 0)
]).forEach { $0.isActive = true }

view.setNeedsLayout()
view.layoutIfNeeded()

// How big should padding next to the stack's last item be?
stackView.headPadding = 0

// Which direction should new items be pushed in?
stackView.growthDirection = .down

// Separate by lines, padding or nothing at all?
stackView.separationStyle = .line(thikness: 2.0, color: .black)
						 // .padding(size: 20.0)
						 // .none

// If you want your stack gradually fade away, you can pick any of the styles, or combine them!
stackView.fadingStyle = .combined(styles:
	[
		.tint(color: .white, preLastAlpha: 0.9, alphaDecrement: 0.1),
		.gradientMask(effectDistance: stackView.bounds.height * 0.7)
	]
) // Or just .none

// You can swipe up-down or left-right to control your flow, and/or also tap inactive stack area to pop any number of items (depends on where you tap)
stackView.userNavigationOptions = [.swipe, .tap]

// Fast hops or sloooooow animation?
stackView.transitionDuration = 0.25

// Set to false if you don't need automatic safe area detection/adoption
stackView.isSeekingSafeArea = true

// Set to false to turn off stretch-out behaviour for your content items during autolayout updates
stackView.isAutoresizingItems = true

stackView.push(myCustomView)

stackView.push(myCustomView, title: "Step ♦️")

// Define custom top bar appearance

let topBarAppearance: StackItemAppearance.TopBar = {
	let popButtonAppearance: StackItemAppearance.TopBar.Button
	let pushButtonAppearance: StackItemAppearance.TopBar.Button

	// You can use images or attributed text for navigation buttons

	let preferIconsOverText = false

	if preferIconsOverText { // Use icons
		popButtonAppearance = StackItemAppearance.TopBar.Button(icon: UIImage(named: "back")!)
		pushButtonAppearance = StackItemAppearance.TopBar.Button(icon: UIImage(named: "forth")!)
	} else { // Use text
		let popButtonTitle = NSAttributedString(string: "♦️⬅️", attributes: [.foregroundColor : UIColor.blue])
		popButtonAppearance = StackItemAppearance.TopBar.Button(title: popButtonTitle)

		let pushButtonTitle = NSAttributedString(string: "➡️💎", attributes: [.foregroundColor : UIColor.blue])
		pushButtonAppearance = StackItemAppearance.TopBar.Button(title: pushButtonTitle)
	}

	let customBarAppearance = StackItemAppearance.TopBar(backgroundColor: Utils.randomPastelColor(), titleFont: .italicSystemFont(ofSize: 17.0), titleTextColor: .white, popButtonIdentity: popButtonAppearance, pushButtonIdentity: pushButtonAppearance)

	return customBarAppearance
}()

// Set appearence for the whole item, including previously created top bar appearance

let customAppearance = StackItemAppearance(backgroundColor: Utils.randomPastelColor(), topBarAppearance: topBarAppearance)

// Push it all to the stack!

stackView.push(myCustomView, title: "Step ♦️", customAppearance: customAppearance)

stackView.pop()

stackView.pop(numberOfItems)

func stackFlowViewDidRequestPop(_ stackView: StackFlowView, numberOfItems: Int) {
	log(message: "Requested to go \(numberOfItems) steps back", from: self)
	stackView.pop(numberOfItems)
}

func stackFlowViewDidRequestPush(_ stackView: StackFlowView) {
	log(message: "Requested next item", from: self)
	goToNextStep()
}

func stackFlowViewWillPop(_ stackView: StackFlowView) {
	log(message: "About to go one item back", from: self)
}

func stackFlowViewDidPop(_ stackView: StackFlowView) {
	log(message: "Went one item back", from: self)
}

func stackFlowView(_ stackView: StackFlowView, willPush view: UIView) {
	log(message: "About to to go to the next step", from: self)
}

func stackFlowView(_ stackView: StackFlowView, didPush view: UIView) {
	log(message: "Went to next step with view: \(view)", from: self)
}

class MyFlowController: UIViewController {
	// MARK: - Flow definition -

	enum MyFlowStep: Int {
		case none = -1
		case one = 0, two, three, four

		static var count: Int { return 4 }

		var title: String {
			switch self {
			default:
				return "Step \(shortSymbol)"
			}
		}

		var shortSymbol: String {
			switch self {
			case .one:
				return "♦️"

			case .two:
				return "♠️"

			case .three:
				return "💎"

			case .four:
				return "🔮"

			case .none:
				return "❌"
			}
		}

		var prevStep: FlowStep? {
			let prevValue = rawValue - 1
			return prevValue >= 0 ? FlowStep(rawValue: prevValue) : nil
		}

		var nextStep: FlowStep? {
			let nextValue = rawValue + 1
			return nextValue < FlowStep.count ? FlowStep(rawValue: nextValue) : nil
		}
	}

    // MARK: - Properties -

    private let stackView = StackFlowView()

    /* — Whenever this property is set, you can prepare the next view to push — */

    private var currentStep: MyFlowStep = .none {
		didSet {
			// Get identity of the current step

			let itemTitle = currentStep.title

			// You can optionall use bounding steps' identity for something like setting custom navigation buttons

			let prevItemSymbol = currentStep.prevStep?.shortSymbol
			let nextItemSymbol = currentStep.nextStep?.shortSymbol

			// Here you should construct your custom UIView considering purposes of this particular step

			let itemView = stepView(for: currentStep)

			// Now you can push your custom view using superclass `push()` method!

			stackView.push(itemView, title: itemTitle)
		}
	}

	// MARK: - View constructor -

	private func stepView(for step: MyFlowStep) -> UIView {
		let stepView: UIView

		// Note this `safeSize` property of StackFlowView. You should use it to get info about its available content area, not blocked by any views outside of safe area

		let safeStackFlowViewWidth = stackView.safeSize.width

		// Build custom view for any given step

		switch step {
		case .one:
			stepView = UIView(frame: CGRect(x: 0, y: 0, width: safeStackFlowViewWidth, height: 100.0))

		case .two:
			stepView = UIView(frame: CGRect(x: 0, y: 0, width: safeStackFlowViewWidth, height: 200.0))

		default:
			stepView = UIView(frame: CGRect(x: 0, y: 0, width: safeStackFlowViewWidth, height: 300.0))
		}

		return stepView
	}
}