.NET\05_MVC_Users\CORE\Authentication\Services\ICookieAuthService.cs

                
                    namespace CORE.Authentication.Services
{
    /// <summary>
    /// Defines methods for handling cookie-based 
    /// authentication operations.
    /// </summary>
    public interface ICookieAuthService
    {
        // Properties can also be defined in interfaces with C#.
        // User ID readonly property to get the authenticated
        // user's ID.
        public int UserId { get; }

        /// <summary>
        /// Signs in a user by creating an authentication cookie.
        /// </summary>
        /// <param name="userId">The unique identifier of 
        /// the user.</param>
        /// <param name="userName">The user name of the user.
        /// </param>
        /// <param name="userRoleNames">A collection of role 
        /// names assigned to the user.</param>
        /// <param name="expiration">Optional expiration date 
        /// and time for the authentication cookie. 
        /// If not specified, a default value (null) is used.
        /// </param>
        /// <param name="isPersistent">Indicates whether the 
        /// authentication cookie should persist across browser 
        /// sessions.</param>
        /// <returns>A task representing the asynchronous 
        /// sign-in operation.</returns>
        public Task SignIn(int userId, string userName, 
            IEnumerable<string> userRoleNames, 
            DateTime? expiration = default, 
            bool isPersistent = true);

        /// <summary>
        /// Signs out the current user by removing the 
        /// authentication cookie.
        /// </summary>
        /// <returns>A task representing the asynchronous 
        /// sign-out operation.</returns>
        public Task SignOut();
    }
}