awesome-uiwidgets/AwesomeUIWidgets/Assets/Scripts/AdditionalWidgets/LinkPreview/url_linkifier.cs

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using ChatComponents;
using JetBrains.Annotations;
using Unity.UIWidgets.animation;
using Unity.UIWidgets.async;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.painting;
using Unity.UIWidgets.rendering;
using Unity.UIWidgets.ui;
using Unity.UIWidgets.widgets;
using UnityEngine.UIElements;
using Image = Unity.UIWidgets.widgets.Image;
using TextStyle = Unity.UIWidgets.painting.TextStyle;

namespace UIWidgetsSample
{
  public static class urlLinkifierUtils
  {
    public static Regex _urlRegex = new Regex(
      @"^(.*?)((?:https?:\/\/|www\.)[^\s/$.?#].[^\s]*)"
     
    );

    public static Regex  _looseUrlRegex =new Regex(
      @"^(.*?)((https?:\/\/)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,4}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*))"
     
    );

    public static Regex  _protocolIdentifierRegex =new Regex(
      @"^(https?:\/\/)"
    
    );

  }
  // Utility class that implements [Linkifier.parse] method.
/// Used to find links in the text.
/*public class UrlLinkifier : Linkifier {
  /// Default constructor
  UrlLinkifier();

  /// Parses text to find all links inside it
  @override
  List<LinkifyElement> parse(elements, options) {
    final list = <LinkifyElement>[];

    elements.forEach((element) {
      if (element is TextElement) {
        var loose = false;
        var match = _urlRegex.firstMatch(element.text);

        if (match?.group(1)?.isNotEmpty == true) {
          final looseMatch = _looseUrlRegex.firstMatch(match!.group(1)!);
          if (looseMatch != null) {
            match = looseMatch;
            loose = true;
          }
        }

        if (match == null && options.looseUrl) {
          match = _looseUrlRegex.firstMatch(element.text);
          loose = true;
        }

        if (match == null) {
          list.add(element);
        } else {
          final text = element.text.replaceFirst(match.group(0)!, "");

          if (match.group(1)?.isNotEmpty == true) {
            list.add(TextElement(match.group(1)!));
          }

          if (match.group(2)?.isNotEmpty == true) {
            var originalUrl = match.group(2)!;
            String? end;

            if (options.excludeLastPeriod &&
                originalUrl[originalUrl.length - 1] == ".") {
              end = ".";
              originalUrl = originalUrl.substring(0, originalUrl.length - 1);
            }

            final url = originalUrl;

            if (loose || !originalUrl.startsWith(_protocolIdentifierRegex)) {
              originalUrl = (options.defaultToHttps ? "https://" : "http://") +
                  originalUrl;
            }

            list.add(
              UrlElement(
                originalUrl,
                url,
              ),
            );

            if (end != null) {
              list.add(TextElement(end));
            }
          }

          if (text.isNotEmpty) {
            list.addAll(parse([TextElement(text)], options));
          }
        }
      } else {
        list.add(element);
      }
    });

    return list;
  }
}

/// Represents an element containing a link

class UrlElement : LinkableElement {
  /// Creates [UrlElement]
  UrlElement(String url, [String? text]) : super(text, url);

  @override
  String toString() {
    return "LinkElement: "$url" ($text)";
  }

  @override
  bool operator ==(other) => equals(other);

  @override
  bool equals(other) => other is UrlElement && super.equals(other);

  @override
  // ignore: unnecessary_overrides
  int get hashCode => super.hashCode;
}*/

    //}  
}