UrlValidator

namespace _02_ValidateURL_Regex
{
    using System;
    using System.Net;
    using System.Text.RegularExpressions;

    class Startup
    {
        static void Main()
        {
            string urlPattern = @"^(?<protocol>(?<http>http)|https):\/\/(?<host>[\w-]+\.[a-z]{2,4})(?::(?<port>(?(http)(80|8080)|(443))))?(?<path>(\/[\w\d]*)*)?((?<!\/).[a-z]+)?(?:\?(?<query>(?:\b\w+=\w+&?)*))?(?:#(?<fragment>\w+)*)?$";

            Regex regex = new Regex(urlPattern);

            string url = WebUtility.UrlDecode(Console.ReadLine());

            Match match = regex.Match(url);

            if (!match.Success)
            {
                Console.WriteLine("Invalid URL!");
                return;
            }

            string protocol = match.Groups["protocol"].ToString();
            string host = match.Groups["host"].ToString();
            string port = match.Groups["port"].ToString();
            string path = match.Groups["path"].ToString();
            string query = match.Groups["query"].ToString();
            string fragment = match.Groups["fragment"].ToString();

            if (string.IsNullOrEmpty(port))
            {
                if (protocol == "http")
                {
                    port = "80";
                }
                else
                {
                    port = "443";
                }
            }

            if (string.IsNullOrEmpty(path))
            {
                path = "/";
            }

            Console.WriteLine("Protocol: {0}", protocol);
            Console.WriteLine("Host: {0}", host);
            Console.WriteLine("Port: {0}", port);
            Console.WriteLine("Path: {0}", path);

            if (!string.IsNullOrEmpty(query))
            {
                Console.WriteLine("Query: {0}", query);
            }

            if (!string.IsNullOrEmpty(fragment))
            {
                Console.WriteLine("Fragment: {0}", fragment);
            }
        }
    }
}