Simple UILabel subclass with clickable text

InteractiveLabel.swift

public class InteractiveLabel: UILabel {
    private struct InteractiveText: Equatable {
        let range: Range<String.Index>
        let defaultColor: UIColor
        let highlightedColor: UIColor
        let action: () -> Void

        static func == (lhs: InteractiveText, rhs: InteractiveText) -> Bool {
            return lhs.range == rhs.range
        }
    }

    private var manager: NSLayoutManager!
    private var storage: NSTextStorage!
    private var container: NSTextContainer!
    private var interactiveList: [InteractiveText] = []

    private var lastSelection: InteractiveText?

    public override var attributedText: NSAttributedString? {
        didSet {
            updateTouchDetector()
        }
    }

    public func addInteractiveText(_ interactiveText: String, defaultColor: UIColor? = nil,
                                   highlightedColor: UIColor? = nil, action: @escaping () -> Void) {
        guard let text = self.text, let range = text.range(of: interactiveText) else {
            return
        }
        addInteractiveText(range: range, defaultColor: defaultColor, highlightedColor: highlightedColor, action: action)
    }

    public func addInteractiveText(range: Range<String.Index>, defaultColor: UIColor? = nil,
                                   highlightedColor: UIColor? = nil, action: @escaping () -> Void) {
        interactiveList.removeAll(where: {$0.range.overlaps(range)})
        let interactiveText = InteractiveText(range: range, defaultColor: defaultColor ?? textColor,
                highlightedColor: highlightedColor ?? textColor, action: action)
        interactiveList.append(interactiveText)
        highlightInteractiveText(false, text: interactiveText)
    }

    private func updateTouchDetector() {
        guard let attributedText = attributedText else {
            return
        }

        storage = NSTextStorage(attributedString: attributedText)
        manager = NSLayoutManager()
        storage.addLayoutManager(manager)

        container = NSTextContainer(size: frame.size) //this frame will be invalid during init
        container.lineFragmentPadding = 0.0
        container.lineBreakMode = lineBreakMode
        container.maximumNumberOfLines = numberOfLines

        manager.addTextContainer(container)
    }

    private func highlightInteractiveText(_ highlight: Bool, text: InteractiveText) {
        let attributedText = self.attributedText ?? NSAttributedString(string: self.text ?? "")
        let modifiedText = NSMutableAttributedString(attributedString: attributedText)
        let nsRange = NSRange(text.range, in: attributedText.string)
        let color = highlight ? text.highlightedColor : text.defaultColor
        modifiedText.addAttribute(.foregroundColor, value: color, range: nsRange)
        self.attributedText = modifiedText
    }

    public override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesBegan(touches, with: event)
        guard interactiveList.count > 0, let touchLocation = touches.first?.location(in: self) else {
            return
        }

        let indexOfCharacter = manager.characterIndex(for: touchLocation, in: container, fractionOfDistanceBetweenInsertionPoints: nil)
        guard indexOfCharacter != NSNotFound, let text = self.text,
              let selection = interactiveList.first(where: {$0.range ~= text.index(text.startIndex, offsetBy: indexOfCharacter) }) else {
            return
        }

        highlightInteractiveText(true, text: selection)
        lastSelection = selection
    }

    public override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesMoved(touches, with: event)
        guard let last = lastSelection, let touchLocation = touches.first?.location(in: self) else {
            return
        }

        let indexOfCharacter = manager.characterIndex(for: touchLocation, in: container, fractionOfDistanceBetweenInsertionPoints: nil)

        if indexOfCharacter != NSNotFound, let text = self.text,
                last.range.contains(text.index(text.startIndex, offsetBy: indexOfCharacter)) {
            highlightInteractiveText(true, text: last)
        } else {
            highlightInteractiveText(false, text: last)
        }
    }

    public override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesEnded(touches, with: event)
        guard let last = lastSelection, let touchLocation = touches.first?.location(in: self) else {
            return
        }

        let indexOfCharacter = manager.characterIndex(for: touchLocation, in: container, fractionOfDistanceBetweenInsertionPoints: nil)
        if indexOfCharacter != NSNotFound, let text = self.text,
           last.range.contains(text.index(text.startIndex, offsetBy: indexOfCharacter)) {
            last.action()
        }

        highlightInteractiveText(false, text: last)
        lastSelection = nil
    }

    public override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesCancelled(touches, with: event)
        guard let last = lastSelection else {
            return
        }
        highlightInteractiveText(false, text: last)
        lastSelection = nil
    }
}