// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Text;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.WebUtilities;
 
namespace Microsoft.AspNetCore.Identity.UI.V4.Pages.Account.Internal;
 
/// <summary>
///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
///     directly from your code. This API may change or be removed in future releases.
/// </summary>
[AllowAnonymous]
[IdentityDefaultUI(typeof(ConfirmEmailChangeModel<>))]
public abstract class ConfirmEmailChangeModel : PageModel
{
    /// <summary>
    ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
    ///     directly from your code. This API may change or be removed in future releases.
    /// </summary>
    [TempData]
    public string? StatusMessage { get; set; }
 
    /// <summary>
    ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
    ///     directly from your code. This API may change or be removed in future releases.
    /// </summary>
    public virtual Task<IActionResult> OnGetAsync(string userId, string email, string code) => throw new NotImplementedException();
}
 
internal sealed class ConfirmEmailChangeModel<TUser> : ConfirmEmailChangeModel where TUser : class
{
    private readonly UserManager<TUser> _userManager;
    private readonly SignInManager<TUser> _signInManager;
 
    public ConfirmEmailChangeModel(UserManager<TUser> userManager, SignInManager<TUser> signInManager)
    {
        _userManager = userManager;
        _signInManager = signInManager;
    }
 
    public override async Task<IActionResult> OnGetAsync(string userId, string email, string code)
    {
        if (userId == null || email == null || code == null)
        {
            return RedirectToPage("/Index");
        }
 
        var user = await _userManager.FindByIdAsync(userId);
        if (user == null)
        {
            return NotFound($"Unable to load user with ID '{userId}'.");
        }
 
        code = Encoding.UTF8.GetString(WebEncoders.Base64UrlDecode(code));
        var result = await _userManager.ChangeEmailAsync(user, email, code);
        if (!result.Succeeded)
        {
            StatusMessage = "Error changing email.";
            return Page();
        }
 
        // In our UI email and user name are one and the same, so when we update the email
        // we need to update the user name.
        var setUserNameResult = await _userManager.SetUserNameAsync(user, email);
        if (!setUserNameResult.Succeeded)
        {
            StatusMessage = "Error changing user name.";
            return Page();
        }
 
        await _signInManager.RefreshSignInAsync(user);
        StatusMessage = "Thank you for confirming your email change.";
        return Page();
    }
}