using System;
using System.Security.Claims;
using System.Threading.Tasks;
using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.Owin;
using Microsoft.Owin.Security;

namespace Umbraco.Web.Security.Identity
{
    public static class AuthenticationManagerExtensions
    {
        private static ExternalLoginInfo GetExternalLoginInfo(AuthenticateResult result)
        {
            if (result == null || result.Identity == null)
            {
                return null;
            }
            var idClaim = result.Identity.FindFirst(ClaimTypes.NameIdentifier);
            if (idClaim == null)
            {
                return null;
            }
            // By default we don't allow spaces in user names
            var name = result.Identity.Name;
            if (name != null)
            {
                name = name.Replace(" ", "");
            }
            var email = result.Identity.FindFirstValue(ClaimTypes.Email);
            return new ExternalLoginInfo
            {
                ExternalIdentity = result.Identity,
                Login = new UserLoginInfo(idClaim.Issuer, idClaim.Value),
                DefaultUserName = name,
                Email = email
            };
        }

        /// <summary>
        ///     Extracts login info out of an external identity
        /// </summary>
        /// <param name="manager"></param>
        /// <param name="authenticationType"></param>
        /// <returns></returns>
        public static async Task<ExternalLoginInfo> GetExternalLoginInfoAsync(this IAuthenticationManager manager, string authenticationType)
        {
            if (manager == null)
            {
                throw new ArgumentNullException("manager");
            }
            return GetExternalLoginInfo(await manager.AuthenticateAsync(authenticationType));
        }
    }
}