// 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.Threading.Tasks;
using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
using Microsoft.CodeAnalysis.SignatureHelp;
 
namespace Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.SignatureHelp;
 
internal sealed partial class Controller
{
    internal sealed partial class Session
    {
        private void SetModelExplicitlySelectedItem(Func<Model, SignatureHelpItem> selector)
        {
            this.Computation.ThreadingContext.ThrowIfNotOnUIThread();
 
            Computation.ChainTaskAndNotifyControllerWhenFinished(
                (model, cancellationToken) => Task.FromResult(SetModelExplicitlySelectedItemInBackground(model, selector)),
                updateController: false);
        }
 
        private Model? SetModelExplicitlySelectedItemInBackground(
            Model? model,
            Func<Model, SignatureHelpItem> selector)
        {
            this.Computation.ThreadingContext.ThrowIfNotOnBackgroundThread();
            if (model == null)
                return null;
 
            var selectedItem = selector(model);
            Contract.ThrowIfFalse(model.Items.Contains(selectedItem));
 
            return model.WithSelectedItem(selectedItem, userSelected: true);
        }
    }
}