// 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 Microsoft.CodeAnalysis.Editor.Tagging;
using Microsoft.CodeAnalysis.Text;
using Microsoft.VisualStudio.Text;
 
namespace Microsoft.CodeAnalysis.Editor.Shared.Tagging
{
    internal partial class TaggerEventSources
    {
        private class DocumentActiveContextChangedEventSource : AbstractWorkspaceTrackingTaggerEventSource
        {
            public DocumentActiveContextChangedEventSource(ITextBuffer subjectBuffer)
                : base(subjectBuffer)
            {
            }
 
            protected override void ConnectToWorkspace(Workspace workspace)
                => workspace.DocumentActiveContextChanged += OnDocumentActiveContextChanged;
 
            protected override void DisconnectFromWorkspace(Workspace workspace)
                => workspace.DocumentActiveContextChanged -= OnDocumentActiveContextChanged;
 
            private void OnDocumentActiveContextChanged(object? sender, DocumentActiveContextChangedEventArgs e)
            {
                var document = SubjectBuffer.AsTextContainer().GetOpenDocumentInCurrentContext();
 
                if (document != null && document.Id == e.NewActiveContextDocumentId)
                {
                    this.RaiseChanged();
                }
            }
        }
    }
}