HyperlinkLabel.swift

import UIKit

class HyperlinkLabel: UILabel {
    
    var stringAndUrl: [String: URL] = [:] {
        didSet {
            attributedText = attributedText()
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        commonInit()
    }
    
    func commonInit() {
        numberOfLines = 0
        isUserInteractionEnabled = true
        let tap = UITapGestureRecognizer(target: self, action: #selector(linkTapped(gesture:)))
        addGestureRecognizer(tap)
    }
}

fileprivate extension HyperlinkLabel {
    
    @objc func linkTapped(gesture: UITapGestureRecognizer) {
        
        guard let text = self.text as NSString? else {
            return
        }
        
        for (string, url) in stringAndUrl {
            let range = text.localizedStandardRange(of: string)

            let tapLocation = gesture.location(in: self)
            let index = self.indexOfAttributedTextCharacterAtPoint(point: tapLocation)

            if checkRange(range, containsIndex: index) {
                SafariManager.show(url)
                return
            }
        }
        
    }
    
    func attributedText() -> NSAttributedString {
        
        guard let text = self.text else {
            return NSAttributedString(string: "")
        }
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.alignment = textAlignment
        let attributedString =
            NSMutableAttributedString(string: text, attributes: [
                .paragraphStyle: paragraphStyle,
                .font: self.font as Any
            ])
        let boldFontAttribute = [
            NSAttributedString.Key.font: self.font.bold(),
            NSAttributedString.Key.foregroundColor: UIColor.tintColor
        ]
        for str in stringAndUrl.keys {
            attributedString.addAttributes(boldFontAttribute, range: (text as NSString).range(of: str))
        }
        return attributedString
    }
    
    func indexOfAttributedTextCharacterAtPoint(point: CGPoint) -> Int {
        guard let attributedText = attributedText else {
            preconditionFailure("This method is developed for attributed string")
        }
        let textStorage = NSTextStorage(attributedString: attributedText)
        let layoutManager = NSLayoutManager()
        textStorage.addLayoutManager(layoutManager)
        let textContainer = NSTextContainer(size: self.frame.size)
        textContainer.lineFragmentPadding = 0
        textContainer.maximumNumberOfLines = self.numberOfLines
        textContainer.lineBreakMode = self.lineBreakMode
        layoutManager.addTextContainer(textContainer)

        let index = layoutManager.characterIndex(for: point, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        return index
    }
    
    func checkRange(_ range: NSRange, containsIndex index: Int) -> Bool {
        return index > range.location && index < range.location + range.length
    }
}