/* ========================================================================
 * Copyright (c) 2005-2026 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 * The complete license agreement can be found here:
 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System.Threading;
using System.Threading.Tasks;
using Opc.Ua.Identity;

namespace Opc.Ua.Server
{
    /// <summary>
    /// Accepts anonymous user identity tokens.
    /// </summary>
    public sealed class AnonymousAuthenticator : IUserTokenAuthenticator
    {
        /// <inheritdoc/>
        public UserTokenType TokenType => UserTokenType.Anonymous;

        /// <inheritdoc/>
        public string? IssuedTokenProfileUri => null;

        /// <inheritdoc/>
        public ValueTask<AuthenticationResult> AuthenticateAsync(
            AuthenticationContext context,
            CancellationToken ct = default)
        {
            if (context.TokenHandler is not AnonymousIdentityTokenHandler)
            {
                return new ValueTask<AuthenticationResult>(AuthenticationResult.NotHandled);
            }

            return new ValueTask<AuthenticationResult>(
                AuthenticationResult.Accept(new UserIdentity(context.TokenHandler)));
        }
    }
}