Refactor. Add data layer

BudgetApp/Components/Pages/Register.razor

@@ -1,5 +1,6 @@
 @page "/register"
 @layout AuthLayout
+@using BudgetApp.Data.Entities
 @using Microsoft.AspNetCore.Identity
 @inject UserManager<ApplicationUser> UserManager
 @inject SignInManager<ApplicationUser> SignInManager
@@ -12,9 +13,9 @@
 <EditForm Model="Model" OnValidSubmit="HandleRegister" FormName="register">
     <DataAnnotationsValidator />
 
-    @if (!string.IsNullOrEmpty(errorMessage))
+    @if (!string.IsNullOrEmpty(_errorMessage))
     {
-        <div class="alert alert-danger">@errorMessage</div>
+        <div class="alert alert-danger">@_errorMessage</div>
     }
 
     <div class="mb-3">
@@ -40,44 +41,4 @@
 
 <p class="text-center mt-3">
     Already have an account? <a href="/login">Sign in</a>
-</p>
-
-@code {
-    [SupplyParameterFromForm]
-    private RegisterModel Model { get; set; } = new();
-
-    private string? errorMessage;
-
-    private async Task HandleRegister()
-    {
-        errorMessage = null;
-
-        var user = new ApplicationUser { UserName = Model.Email, Email = Model.Email };
-        var result = await UserManager.CreateAsync(user, Model.Password);
-
-        if (result.Succeeded)
-        {
-            await SignInManager.SignInAsync(user, isPersistent: false);
-            Navigation.NavigateTo("/", forceLoad: true);
-        }
-        else
-        {
-            errorMessage = string.Join(" ", result.Errors.Select(e => e.Description));
-        }
-    }
-
-    private sealed class RegisterModel
-    {
-        [System.ComponentModel.DataAnnotations.Required(ErrorMessage = "Email is required")]
-        [System.ComponentModel.DataAnnotations.EmailAddress(ErrorMessage = "Invalid email address")]
-        public string Email { get; set; } = string.Empty;
-
-        [System.ComponentModel.DataAnnotations.Required(ErrorMessage = "Password is required")]
-        [System.ComponentModel.DataAnnotations.MinLength(8, ErrorMessage = "Password must be at least 8 characters")]
-        public string Password { get; set; } = string.Empty;
-
-        [System.ComponentModel.DataAnnotations.Required(ErrorMessage = "Please confirm your password")]
-        [System.ComponentModel.DataAnnotations.Compare(nameof(Password), ErrorMessage = "Passwords do not match")]
-        public string ConfirmPassword { get; set; } = string.Empty;
-    }
-}
+</p>