highlighting.swift

class HighlightTextViewController: UIViewController {

    var textView = UITextView()

    let theme: Theme = MaterialLightTheme()
    
    lazy var highlighter: TextViewHighlighter = {
        let abcLanguage = Language(language: tree_sitter_abc())

        let url = Bundle.main.url(forResource: "highlights", withExtension: "scm")
        let query = try! abcLanguage.query(contentsOf: url!)

        let attrProvider: TextViewSystemInterface.AttributeProvider = { token in
            // print(token)
            // TODO extract and add fonts etc
            var attrs: [NSAttributedString.Key: Any] = [:]
            
            if let foregroundColor = self.theme.textColor(for: token.name) {
                attrs[.foregroundColor] = foregroundColor
            }

            return attrs
        }

        return try! TextViewHighlighter(textView: textView,
                                        language: abcLanguage,
                                        highlightQuery: query,
                                        attributeProvider: attrProvider)
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        _ = highlighter.textView

        textView.isEditable = true
        textView.font = UIFont.systemFont(ofSize: 20)
        textView.backgroundColor = theme.backgroundColor
        view.addSubview(textView)
        textView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            textView.topAnchor.constraint(equalTo: view.topAnchor),
            textView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            textView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            textView.trailingAnchor.constraint(equalTo: view.trailingAnchor)
        ])
    }
    
    func invalidateHighlighter() {
        DispatchQueue.main.async {
            print(self.textView.text)
            self.highlighter.invalidate()

        }
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
            let text = self.textView.text
            self.textView.text = "jsk"
            DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
                
                self.textView.text = text
                self.highlighter.invalidate()
            }
        }
    }

}

struct HighlightingTextView: UIViewControllerRepresentable {

    @Binding var text: String

    func makeUIViewController(context: Context) -> HighlightTextViewController {
        let viewController = HighlightTextViewController()
        viewController.textView.text = text
        viewController.invalidateHighlighter()
        return viewController
    }

    func updateUIViewController(_ uiViewController: HighlightTextViewController, context: Context) {
        uiViewController.textView.text = text
    }

}