// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Linq;
using System.Threading.Tasks;

namespace Microsoft.AspNetCore.Authorization.Infrastructure
{
    /// <summary>
    /// Implements an <see cref="IAuthorizationHandler"/> and <see cref="IAuthorizationRequirement"/>
    /// which requires the current user must be authenticated.
    /// </summary>
    public class DenyAnonymousAuthorizationRequirement : AuthorizationHandler<DenyAnonymousAuthorizationRequirement>, IAuthorizationRequirement
    {
        /// <summary>
        /// Makes a decision if authorization is allowed based on a specific requirement.
        /// </summary>
        /// <param name="context">The authorization context.</param>
        /// <param name="requirement">The requirement to evaluate.</param>
        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, DenyAnonymousAuthorizationRequirement requirement)
        {
            var user = context.User;
            var userIsAnonymous =
                user?.Identity == null ||
                !user.Identities.Any(i => i.IsAuthenticated);
            if (!userIsAnonymous)
            {
                context.Succeed(requirement);
            }
            return Task.CompletedTask;
        }

        /// <inheritdoc />
        public override string ToString()
        {
            return $"{nameof(DenyAnonymousAuthorizationRequirement)}: Requires an authenticated user.";
        }
    }
}
