using System;

using System.Collections.Generic;

using System.Security.Cryptography;

​

public class RegistrationSystem

{

    private static bool _enableLinkInvitation;

    private static bool _requireConfirmation;

    private static Dictionary<string, User> _userConfirmations = new Dictionary<string, User>();

​

    public static Uri SetLinkInvitationSetting(bool enableLinkInvitation, bool requireConfirmation)

    {

        _enableLinkInvitation = enableLinkInvitation;

        _requireConfirmation = requireConfirmation;

​

        if (enableLinkInvitation)

        {

            return new Uri("https://example.com/register");

        }

        else

        {

            return null;

        }

    }

​

    public static class Account

    {

        public static Uri GetRegistrationConfirmUri(User user)

        {

            string token = GenerateConfirmationToken();

            _userConfirmations[token] = user;

            return new Uri($"https://example.com/confirm?token={token}");

        }

​

        private static string GenerateConfirmationToken()

        {

            using (var rng = new RNGCryptoServiceProvider())

            {

                var tokenBytes = new byte[32]; // 256-bit token

                rng.GetBytes(tokenBytes);

                return Convert.ToBase64String(tokenBytes);

            }

        }

    }

​

    public static void JoinPortalNewUser(User user, Uri confirmUri, bool expectConfirmationPage)

    {

        // Simulate opening the confirmUri in a browser (no actual browser interaction needed)

        Console.WriteLine($"User {user.Email} opening confirmation link: {confirmUri}");

​

        if (expectConfirmationPage)

        {

            // Simulate checking for a confirmation page

            Console.WriteLine("Confirmation page displayed.");

​

            // Extract token and confirm user

            string token = confirmUri.Query.Substring(confirmUri.Query.IndexOf("token=") + 6);

             if (_userConfirmations.ContainsKey(token))

            {

               User confirmingUser =  _userConfirmations[token];

               confirmingUser.IsConfirmed = true;

               _userConfirmations.Remove(token);

​

               Console.WriteLine($"User confirmed: {confirmingUser.Email}");

            }

            else{

                 Console.WriteLine($"Confirmation Failed. Token {token} is invalid");

            }

​

        }

    }

​

    public static void RejectUsrInvitationWithAssertAuthImpossabilityCommonPart(User user)

    {

        RejectUserInvitCommon(user);

​

        // Simulate failed login attempt

        Console.WriteLine($"Login attempt failed for user: {user.Email}");

    }

​

     public static void RejectUserInvitCommon(User user)

    {

       user.IsRejected = true;

       Console.WriteLine($"User {user.Email} Rejected Invitation");

    }

​

    public static string getTextForRegCompletePage()

    {

        return "Registration Complete!";

    }

     public class User

    {

        public string Email { get; set; }

        public string Password { get; set; }

        public bool IsConfirmed { get; set; }

        public bool IsRejected {get; set;}

    }

​

    public static void Main(string[] args)

    {

        // Configure registration settings

        Uri invitationLink = SetLinkInvitationSetting(true, true);

        Console.WriteLine($"Invitation Link: {invitationLink}");

​

        // Create a new user

        User newUser = new User { Email = "testuser@example.com", Password = "Password123" };

​

        // Get registration confirmation URI

        Uri confirmUri = Account.GetRegistrationConfirmUri(newUser);

​

        // Simulate user joining and confirming

        JoinPortalNewUser(newUser, confirmUri, true);

​

        //Simulate User Rejects the invitation

        RejectUsrInvitationWithAssertAuthImpossabilityCommonPart(newUser);

​

        // Visit base URL and check for registration complete page

         if(newUser.IsConfirmed && newUser.IsRejected)

         {

             Console.WriteLine(getTextForRegCompletePage());

         }

    }

}