BusinessLogic/BusinessLogic/UserLogic.cs

@@ -25,11 +25,14 @@ namespace BusinessLogic.BusinessLogic
     {
         private readonly ILogger _logger;
         private readonly IUserStorage _userStorage;
+        private readonly ITwoFactorAuthService _twoFactorAuthService;
 
-        public UserLogic(ILogger<UserLogic> logger, IUserStorage userStorage)
+        public UserLogic(ILogger<UserLogic> logger, IUserStorage userStorage,
+            ITwoFactorAuthService twoFactorAuthService)
         {
             _logger = logger;
             _userStorage = userStorage;
+            _twoFactorAuthService = twoFactorAuthService;
         }
 
         public string Create(UserBindingModel model)
@@ -53,6 +56,9 @@ namespace BusinessLogic.BusinessLogic
 
             MailSender.Send(new MailRegistration(user));
 
+            string code = _twoFactorAuthService.GenerateCode();
+            MailSender.Send(new MailTwoFactorCode(user, code));
+
             return JwtProvider.Generate(user);
         }
 
@@ -132,6 +138,10 @@ namespace BusinessLogic.BusinessLogic
             {
                 throw new AccountException("The passwords don't match.");
             }
+
+            string code = _twoFactorAuthService.GenerateCode();
+            MailSender.Send(new MailTwoFactorCode(user, code));
+
             return JwtProvider.Generate(user);
         }
 
@@ -166,5 +176,10 @@ namespace BusinessLogic.BusinessLogic
                 throw new AccountException("The email is not valid.");
             }
         }
+
+        public bool VerifyCode(string code)
+        {
+            return _twoFactorAuthService.Verify(code);
+        }
     }
 }

BusinessLogic/Tools/Mail/MailTemplates/MailTwoFactorCode.cs

@@ -0,0 +1,21 @@
+using Contracts.BindingModels;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BusinessLogic.Tools.Mail.MailTemplates
+{
+    public class MailTwoFactorCode : Mail
+    {
+        public MailTwoFactorCode(UserBindingModel user, string code)
+        {
+            To = [user.Email];
+            Title = "Ваш код для подтверждения";
+            Body = $"Здравствуйте, {user.SecondName} {user.FirstName}! Вот Ваш код для подтверждения:\n" +
+                $"{code}\n" +
+                $"Если это не Вы, игноритруйте это сообщение.";
+        }
+    }
+}

BusinessLogic/Tools/TwoFactorAuthService.cs

@@ -0,0 +1,42 @@
+using Contracts.BusinessLogicContracts;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BusinessLogic.Tools
+{
+    public class TwoFactorAuthService : ITwoFactorAuthService
+    {
+        private string _code = string.Empty;
+        private const int LENGTH_CODE = 5;
+
+        public string GenerateCode()
+        {
+            _code = _getCode(LENGTH_CODE);
+            return _code;
+        }
+
+        private string _getCode(int length)
+        {
+            string res = "";
+            var rand = new Random();
+            for (int i = 0; i < length; i++)
+            {
+                res += rand.Next(0, 9).ToString();
+            }
+            return res;
+        }
+
+        public bool Verify(string code)
+        {
+            if (_code == string.Empty)
+            {
+                throw new Exception("Source code is not generated.");
+            }
+
+            return _code == code;
+        }
+    }
+}

Contracts/BusinessLogicContracts/ITwoFactorAuthService.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Contracts.BusinessLogicContracts
+{
+    public interface ITwoFactorAuthService
+    {
+        string GenerateCode();
+
+        bool Verify(string code);
+    }
+}

Contracts/BusinessLogicContracts/IUserLogic.cs

@@ -14,6 +14,8 @@ namespace Contracts.BusinessLogicContracts
     {
         string Login(string email, string password);
 
+        bool VerifyCode(string code);
+
         string Create(UserBindingModel model);
 
         UserViewModel Update(UserBindingModel model);

RestAPI/Controllers/UserController.cs

@@ -46,6 +46,21 @@ namespace RestAPI.Controllers
             }
         }
 
+        [HttpPost]
+        public IResult VerifyCode([FromBody] VerifyCodeData data)
+        {
+            try
+            {
+                var res = _userLogic.VerifyCode(data.code);
+                return Results.Ok(res);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error verify code");
+                return Results.Problem(ex.Message);
+            }
+        }
+
         [HttpPost]
         public IResult Registration([FromBody] UserBindingModel model)
         {
@@ -128,4 +143,5 @@ namespace RestAPI.Controllers
     }
 
     public record class UserData(string email, string password);
+    public record class VerifyCodeData(string code);
 }

RestAPI/Program.cs

@@ -20,6 +20,7 @@ builder.Logging.AddLog4Net("log4net.config");
 
 builder.Services.AddTransient<IRoleLogic, RoleLogic>();
 builder.Services.AddTransient<IUserLogic, UserLogic>();
+builder.Services.AddSingleton<ITwoFactorAuthService, TwoFactorAuthService>();
 
 builder.Services.AddTransient<IRoleStorage, RoleStorage>();
 builder.Services.AddTransient<IUserStorage, UserStorage>();