TheInfinityIQ_GCP/src/gcp-backend/GCP.Api/Areas/Identity/Pages/Account/Manage/ExternalLogins.cshtml.cs
#nullable disable

using GCP.Api.Data.Entities;

using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;

namespace GCP.Api.Areas.Identity.Pages.Account.Manage
{
	public class ExternalLoginsModel : PageModel
	{
		private readonly UserManager<User> _userManager;
		private readonly SignInManager<User> _signInManager;
		private readonly IUserStore<User> _userStore;

		public ExternalLoginsModel(
			UserManager<User> userManager,
			SignInManager<User> signInManager,
			IUserStore<User> userStore)
		{
			_userManager = userManager;
			_signInManager = signInManager;
			_userStore = userStore;
		}

		public IList<UserLoginInfo> CurrentLogins { get; set; }
		public IList<AuthenticationScheme> OtherLogins { get; set; }
		public bool ShowRemoveButton { get; set; }

		[TempData]
		public string StatusMessage { get; set; }

		public async Task<IActionResult> OnGetAsync()
		{
			var user = await _userManager.GetUserAsync(User);
			if (user is null)
			{
				return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
			}

			CurrentLogins = await _userManager.GetLoginsAsync(user);
			OtherLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync())
				.Where(auth => CurrentLogins.All(ul => auth.Name != ul.LoginProvider))
				.ToList();

			string passwordHash = null;
			if (_userStore is IUserPasswordStore<User> userPasswordStore)
			{
				passwordHash = await userPasswordStore.GetPasswordHashAsync(user, HttpContext.RequestAborted);
			}

			ShowRemoveButton = passwordHash is not null || CurrentLogins.Count > 1;
			return Page();
		}

		public async Task<IActionResult> OnPostRemoveLoginAsync(string loginProvider, string providerKey)
		{
			var user = await _userManager.GetUserAsync(User);
			if (user is null)
			{
				return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
			}

			var result = await _userManager.RemoveLoginAsync(user, loginProvider, providerKey);
			if (!result.Succeeded)
			{
				StatusMessage = "The external login was not removed.";
				return RedirectToPage();
			}

			await _signInManager.RefreshSignInAsync(user);
			StatusMessage = "The external login was removed.";
			return RedirectToPage();
		}

		public async Task<IActionResult> OnPostLinkLoginAsync(string provider)
		{
			// Clear the existing external cookie to ensure a clean login process
			await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);

			// Request a redirect to the external login provider to link a login for the current user
			var redirectUrl = Url.Page("./ExternalLogins", pageHandler: "LinkLoginCallback");
			var properties = _signInManager.ConfigureExternalAuthenticationProperties(provider, redirectUrl, _userManager.GetUserId(User));
			return new ChallengeResult(provider, properties);
		}

		public async Task<IActionResult> OnGetLinkLoginCallbackAsync()
		{
			var user = await _userManager.GetUserAsync(User);
			if (user is null)
			{
				return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
			}

			var userId = await _userManager.GetUserIdAsync(user);
			var info = await _signInManager.GetExternalLoginInfoAsync(userId);
			if (info is null)
			{
				throw new InvalidOperationException($"Unexpected error occurred loading external login info.");
			}

			var result = await _userManager.AddLoginAsync(user, info);
			if (!result.Succeeded)
			{
				StatusMessage = "The external login was not added. External logins can only be associated with one account.";
				return RedirectToPage();
			}

			// Clear the existing external cookie to ensure a clean login process
			await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);

			StatusMessage = "The external login was added.";
			return RedirectToPage();
		}
	}
}
