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

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;
using Microsoft.Extensions.DependencyInjection;

namespace Microsoft.AspNetCore.DataProtection.KeyManagement;

internal static class KeyEscrowServiceProviderExtensions
{
    /// <summary>
    /// Gets an aggregate <see cref="IKeyEscrowSink"/> from the underlying <see cref="IServiceProvider"/>.
    /// This method may return null if no sinks are registered.
    /// </summary>
    public static IKeyEscrowSink? GetKeyEscrowSink(this IServiceProvider services)
    {
        var escrowSinks = services?.GetService<IEnumerable<IKeyEscrowSink>>()?.ToList();
        return (escrowSinks != null && escrowSinks.Count > 0) ? new AggregateKeyEscrowSink(escrowSinks) : null;
    }

    private sealed class AggregateKeyEscrowSink : IKeyEscrowSink
    {
        private readonly List<IKeyEscrowSink> _sinks;

        public AggregateKeyEscrowSink(List<IKeyEscrowSink> sinks)
        {
            _sinks = sinks;
        }

        public void Store(Guid keyId, XElement element)
        {
            foreach (var sink in _sinks)
            {
                sink.Store(keyId, element);
            }
        }
    }
}