UILabel extension with ReadMore/ ReadLess action

UILabel+Extensions.swift

import UIKit

enum TrailingContent {
    case readmore
    case readless

    var text: String {
        switch self {
        case .readmore: return "...Read More"
        case .readless: return " Read Less"
        }
    }
}

extension UILabel {

    private var minimumLines: Int { return 4 }
    private var highlightColor: UIColor { return .red }

    private var attributes: [NSAttributedString.Key: Any] {
        return [.font: self.font ?? .systemFont(ofSize: 18)]
    }
    
    public func requiredHeight(for text: String) -> CGFloat {
        let label = UILabel(frame: CGRect(x: 0, y: 0, width: frame.width, height: CGFloat.greatestFiniteMagnitude))
        label.numberOfLines = minimumLines
        label.lineBreakMode = NSLineBreakMode.byTruncatingTail
        label.font = font
        label.text = text
        label.sizeToFit()
        return label.frame.height
      }

    func highlight(_ text: String, color: UIColor) {
        guard let labelText = self.text else { return }
        let range = (labelText as NSString).range(of: text)

        let mutableAttributedString = NSMutableAttributedString.init(string: labelText)
        mutableAttributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: color, range: range)
        self.attributedText = mutableAttributedString
    }

    func appendReadmore(after text: String, trailingContent: TrailingContent) {
        self.numberOfLines = minimumLines
        let fourLineText = "\n\n\n"
        let fourlineHeight = requiredHeight(for: fourLineText)
        let sentenceText = NSString(string: text)
        let sentenceRange = NSRange(location: 0, length: sentenceText.length)
        var truncatedSentence: NSString = sentenceText
        var endIndex: Int = sentenceRange.upperBound
        let size: CGSize = CGSize(width: self.bounds.width, height: CGFloat.greatestFiniteMagnitude)
        while truncatedSentence.boundingRect(with: size, options: .usesLineFragmentOrigin, attributes: attributes, context: nil).size.height >= fourlineHeight {
            if endIndex == 0 {
                break
            }
            endIndex -= 1

            truncatedSentence = NSString(string: sentenceText.substring(with: NSRange(location: 0, length: endIndex)))
            truncatedSentence = (String(truncatedSentence) + trailingContent.text) as NSString

        }
        self.text = truncatedSentence as String
        self.highlight(trailingContent.text, color: highlightColor)
    }

    func appendReadLess(after text: String, trailingContent: TrailingContent) {
        self.numberOfLines = 0
        self.text = text + trailingContent.text
        self.highlight(trailingContent.text, color: highlightColor)
    }
}

guard let text = descLbl.text else { return }

    let readmore = (text as NSString).range(of: TrailingContent.readmore.text)
    let readless = (text as NSString).range(of: TrailingContent.readless.text)
    
    print("check Sender CLick" ,sender.didTap(label: descLbl, inRange: readmore))
    
    if sender.didTap(label: descLbl, inRange: readmore) {
        descLbl.appendReadLess(after: textDescription, trailingContent: .readless)
    } else if sender.didTap(label: descLbl, inRange: readless) {
        descLbl.appendReadmore(after: textDescription, trailingContent: .readmore)
    } else { return }
    
    
    its not working for me , please alaborated in storyboard and other configuration