Owin Auth

using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.Owin;
using Microsoft.Owin.Security;
using Microsoft.Owin.Security.Cookies;
using Microsoft.Owin.Security.Facebook;
using Owin;
using System.Security.Claims;
using System.Threading.Tasks;
using System.Web;

namespace MyProject
{
    public partial class Startup
    {
        // For more information on configuring authentication, please visit http://go.microsoft.com/fwlink/?LinkId=301864
        public void ConfigureAuth(IAppBuilder app)
        {
            // Enable the application to use a cookie to store information for the signed in user
            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Account")
            });

            // Use a cookie to temporarily store information about a user logging in with a third party login provider
            app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);


            var facebookOptions = new Microsoft.Owin.Security.Facebook.FacebookAuthenticationOptions
            {
                Provider = new FacebookAuthenticationProvider()
                {
                    OnAuthenticated = (context) =>
                        {
                            var rawUserObjectFromFacebookAsJson = context.User;

                            var userManager = new UserManager<IdentityUser>(new CustomUserStore());

                            var username = rawUserObjectFromFacebookAsJson.Value<string>("username");
                            var user = new IdentityUser(username);
                            //var identity = userManager.CreateIdentity(user, DefaultAuthenticationTypes.ApplicationCookie);

                            var identity = new ClaimsIdentity("Application");
                            identity.AddClaim(new Claim(ClaimTypes.Name, "<user name>"));
                            HttpContext.Current.GetOwinContext().Authentication.AuthenticationResponseGrant = new AuthenticationResponseGrant(identity, new AuthenticationProperties()
                            {
                                IsPersistent = true
                            });

                            //HttpContext.Current.GetOwinContext().Authentication.SignIn(new AuthenticationProperties
                            //{
                            //    IsPersistent = true
                            //}, identity);

                            return Task.FromResult(0);
                        }
                },
                AppId = "xxxxxxxxxxxx",
                AppSecret = "yyyyyyyyyyyyyyyyyyyyyyyy"
            };

            facebookOptions.Scope.Add("email");

            app.UseFacebookAuthentication(facebookOptions);

        }
    }

    public class CustomUserStore : UserStore<IdentityUser>
    {
        public override Task<IdentityUser> FindAsync(UserLoginInfo login)
        {
            return base.FindAsync(login);
        }

        public override Task<IdentityUser> FindByNameAsync(string userName)
        {
            return this.FindByIdAsync(userName);
        }

        public override Task<IdentityUser> FindByIdAsync(string userId)
        {
            return Task.Run<IdentityUser>(() =>
            {
                return new IdentityUser
                {
                    Id = userId,
                    UserName = userId
                };
            });
        }
    }
}