// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Host;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Remote;
 
internal sealed class ClientOptionsProvider<TOptions, TCallback>(RemoteCallback<TCallback> callback, RemoteServiceCallbackId callbackId) : OptionsProvider<TOptions>
    where TCallback : class, IRemoteOptionsCallback<TOptions>
{
    private ImmutableDictionary<string, AsyncLazy<TOptions>> _cache = ImmutableDictionary<string, AsyncLazy<TOptions>>.Empty;
 
    public async ValueTask<TOptions> GetOptionsAsync(LanguageServices languageServices, CancellationToken cancellationToken)
    {
        var lazyOptions = ImmutableInterlocked.GetOrAdd(ref _cache, languageServices.Language, _ => AsyncLazy.Create(
            static (arg, cancellationToken) => arg.self.GetRemoteOptionsAsync(arg.languageServices, cancellationToken), arg: (self: this, languageServices)));
        return await lazyOptions.GetValueAsync(cancellationToken).ConfigureAwait(false);
    }
 
    private Task<TOptions> GetRemoteOptionsAsync(LanguageServices languageServices, CancellationToken cancellationToken)
        => callback.InvokeAsync((callback, cancellationToken) => callback.GetOptionsAsync(callbackId, languageServices.Language, cancellationToken), cancellationToken).AsTask();
}