Expandable label uikit

import UIKit

class ExpandableLabel: UIView {
    // MARK: - UI Components
    private let label: UILabel = {
        let lbl = UILabel()
        lbl.numberOfLines = 2
        lbl.lineBreakMode = .byTruncatingTail
        lbl.font = UIFont.systemFont(ofSize: UIFont.labelFontSize)
        return lbl
    }()

    private let button: UIButton = {
        let btn = UIButton(type: .system)
        btn.setTitle("Show More", for: .normal)
        btn.isHidden = true
        return btn
    }()

    private let stackView: UIStackView = {
        let sv = UIStackView()
        sv.axis = .vertical
        sv.spacing = 4
        return sv
    }()

    // MARK: - Properties
    var text: String? {
        didSet {
            label.text = text
            resetState()
        }
    }

    private var isExpanded = false

    // MARK: - Initialization
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }

    private func commonInit() {
        setupLayout()
        button.addTarget(self, action: #selector(handleButtonTap), for: .touchUpInside)
    }

    // MARK: - Layout
    private func setupLayout() {
        addSubview(stackView)
        stackView.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            stackView.leadingAnchor.constraint(equalTo: leadingAnchor),
            stackView.trailingAnchor.constraint(equalTo: trailingAnchor),
            stackView.topAnchor.constraint(equalTo: topAnchor),
            stackView.bottomAnchor.constraint(equalTo: bottomAnchor)
        ])

        stackView.addArrangedSubview(label)
        stackView.addArrangedSubview(button)
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        updateButtonVisibility()
    }

    // MARK: - State Management
    private func resetState() {
        isExpanded = false
        label.numberOfLines = 2
        setNeedsLayout()
    }

    private func updateButtonVisibility() {
        guard !isExpanded else {
            button.isHidden = true
            return
        }

        button.isHidden = !isTextTruncated()
    }

    private func isTextTruncated() -> Bool {
        guard let text = label.text, !text.isEmpty else { return false }

        let layoutManager = NSLayoutManager()
        let textContainer = NSTextContainer(size: CGSize(
            width: label.bounds.width,
            height: .greatestFiniteMagnitude
        ))
        let textStorage = NSTextStorage(
            string: text,
            attributes: [.font: label.font!]
        )

        layoutManager.addTextContainer(textContainer)
        textStorage.addLayoutManager(layoutManager)

        textContainer.lineFragmentPadding = 0
        textContainer.lineBreakMode = label.lineBreakMode
        textContainer.maximumNumberOfLines = label.numberOfLines

        let numberOfGlyphs = layoutManager.numberOfGlyphs
        var numberOfLines = 0
        var index = 0
        var lineRange = NSRange(location: 0, length: 0)

        while index < numberOfGlyphs {
            layoutManager.lineFragmentRect(forGlyphAt: index, effectiveRange: &lineRange)
            index = NSMaxRange(lineRange)
            numberOfLines += 1
            if numberOfLines > label.numberOfLines {
                return true
            }
        }

        return false
    }

    // MARK: - Action Handling
    @objc private func handleButtonTap() {
        isExpanded = true
        label.numberOfLines = 0
        button.isHidden = true
    }
}


// usage

let expandableLabel = ExpandableLabel()
expandableLabel.text = "Your long text goes here..."
expandableLabel.translatesAutoresizingMaskIntoConstraints = false

// Add to view and set constraints
view.addSubview(expandableLabel)

NSLayoutConstraint.activate([
    expandableLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16),
    expandableLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16),
    expandableLabel.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor)
])