Fix db seeding, migration, repository services

CSR.Application/Services/UserService.cs

@@ -3,12 +3,51 @@ namespace CSR.Application.Services;
 using CSR.Application.Interfaces;
 using CSR.Domain.Entities;
 
-public class UserService(IUserRepository userRepository) : IUserService
+public class UserService(IUserRepository userRepository, Domain.Interfaces.IPasswordHasher passwordHasher) : IUserService
 {
   private readonly IUserRepository _userRepository = userRepository;
+  private readonly Domain.Interfaces.IPasswordHasher _passwordHasher = passwordHasher;
 
-  public void CreateNewUser(string username, string email, string password, bool isAdmin = false)
+  public async Task<IUserService.RegisterNewUserResult> RegisterNewUser
+    (
+      string username,
+      string email,
+      string password
+    )
   {
+    var errors = new List<string>();
+    var (IsValid, Errors) = User.IsValidUsername(username);
+    if (!IsValid)
+    {
+      errors.AddRange(Errors!);
+    }
 
+    if (!User.IsValidEmail(email))
+    {
+      errors.Add("Invalid email address.");
+    }
+
+    (IsValid, Errors) = User.IsValidPassword(password);
+    if (!IsValid)
+    {
+      errors.AddRange(Errors!);
+    }
+
+    var existingUser = await _userRepository.GetByUsernameAsync(username);
+    if (existingUser != null)
+    {
+      errors.Add("Username already exists.");
+    }
+
+    if (errors.Count > 0)
+    {
+      return new IUserService.RegisterNewUserResult(null, errors);
+    }
+
+    // create the new user
+    var user = User.CreateNew(username, email, password, _passwordHasher);
+    user = await _userRepository.AddAsync(user);
+
+    return new IUserService.RegisterNewUserResult(user, null);
   }
 }