// 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.V5.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(RegisterConfirmationModel<>))]
public class RegisterConfirmationModel : 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>
    public string? Email { 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 bool DisplayConfirmAccountLink { 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 string? EmailConfirmationUrl { 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 email, string? returnUrl = null) => throw new NotImplementedException();
}

internal sealed class RegisterConfirmationModel<TUser> : RegisterConfirmationModel where TUser : class
{
    private readonly UserManager<TUser> _userManager;
    private readonly IEmailSender<TUser> _sender;

    public RegisterConfirmationModel(UserManager<TUser> userManager, IEmailSender<TUser> sender)
    {
        _userManager = userManager;
        _sender = sender;
    }

    public override async Task<IActionResult> OnGetAsync(string email, string? returnUrl = null)
    {
        if (email == null)
        {
            return RedirectToPage("/Index");
        }
        returnUrl = returnUrl ?? Url.Content("~/");

        var user = await _userManager.FindByEmailAsync(email);
        if (user == null)
        {
            return NotFound($"Unable to load user with email '{email}'.");
        }

        Email = email;
        // If the email sender is a no-op, display the confirm link in the page
        DisplayConfirmAccountLink = _sender is DefaultMessageEmailSender<TUser> defaultMessageSender && defaultMessageSender.IsNoOp;
        if (DisplayConfirmAccountLink)
        {
            var userId = await _userManager.GetUserIdAsync(user);
            var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
            code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
            EmailConfirmationUrl = Url.Page(
                "/Account/ConfirmEmail",
                pageHandler: null,
                values: new { area = "Identity", userId = userId, code = code, returnUrl = returnUrl },
                protocol: Request.Scheme);
        }

        return Page();
    }
}
