using System.Globalization;
using System.Text.RegularExpressions;

namespace Hua.DotNet.Code.Helper.Html;

public class ResolveLinksHelper
{
	private static readonly Regex regex = new Regex("((http://|https://|www\\.)([A-Z0-9.\\-]{1,})\\.[0-9A-Z?;~&\\(\\)#,=\\-_\\./\\+]{2,})", RegexOptions.IgnoreCase | RegexOptions.Compiled);

	private const string link = "<a href=\"{0}{1}\" rel=\"nofollow\">{2}</a>";

	private const int MAX_LENGTH = 50;

	private static string ShortenUrl(string url, int max)
	{
		if (url.Length <= max)
		{
			return url;
		}
		int num = url.IndexOf("://");
		if (num > -1)
		{
			url = url.Substring(num + 3);
		}
		if (url.Length <= max)
		{
			return url;
		}
		int num2 = url.IndexOf("/") + 1;
		int num3 = url.LastIndexOf("/");
		if (num2 < num3)
		{
			url = url.Remove(num2, num3 - num2);
			url = url.Insert(num2, "...");
		}
		if (url.Length <= max)
		{
			return url;
		}
		int num4 = url.IndexOf("?");
		if (num4 > -1)
		{
			url = url.Substring(0, num4);
		}
		if (url.Length <= max)
		{
			return url;
		}
		int num5 = url.IndexOf("#");
		if (num5 > -1)
		{
			url = url.Substring(0, num5);
		}
		if (url.Length <= max)
		{
			return url;
		}
		num2 = url.LastIndexOf("/") + 1;
		num3 = url.LastIndexOf(".");
		if (num3 - num2 > 10)
		{
			string text = url.Substring(num2, num3 - num2);
			int num6 = url.Length - max + 3;
			if (text.Length > num6)
			{
				url = url.Replace(text, "..." + text.Substring(num6));
			}
		}
		return url;
	}

	public static string FormatText(string text)
	{
		if (string.IsNullOrEmpty(text))
		{
			return string.Empty;
		}
		CultureInfo invariantCulture = CultureInfo.InvariantCulture;
		foreach (Match item in regex.Matches(text))
		{
			text = (item.Value.Contains("://") ? text.Replace(item.Value, string.Format(invariantCulture, "<a href=\"{0}{1}\" rel=\"nofollow\">{2}</a>", string.Empty, item.Value, ShortenUrl(item.Value, 50))) : text.Replace(item.Value, string.Format(invariantCulture, "<a href=\"{0}{1}\" rel=\"nofollow\">{2}</a>", "http://", item.Value, ShortenUrl(item.Value, 50))));
		}
		return text;
	}
}