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+)*)?$";

            while (true)
            {
                Regex regex = new Regex(urlPattern);

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

                Match match = regex.Match(url);

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

                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);
                }
            }

        }
    }
}