// 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.

#nullable disable

using System;
using System.Composition;
using Microsoft.CodeAnalysis.Editor;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Operations;

namespace Microsoft.CodeAnalysis.Interactive;

[ExportWorkspaceServiceFactory(typeof(ITextUndoHistoryWorkspaceService), [WorkspaceKind.Interactive]), Shared]
internal sealed class InteractiveTextUndoHistoryWorkspaceServiceFactory : IWorkspaceServiceFactory
{
    private readonly TextUndoHistoryWorkspaceService _serviceSingleton;

    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public InteractiveTextUndoHistoryWorkspaceServiceFactory(ITextUndoHistoryRegistry textUndoHistoryRegistry)
        => _serviceSingleton = new TextUndoHistoryWorkspaceService(textUndoHistoryRegistry);

    public IWorkspaceService CreateService(HostWorkspaceServices workspaceServices)
        => _serviceSingleton;

    private sealed class TextUndoHistoryWorkspaceService : ITextUndoHistoryWorkspaceService
    {
        private readonly ITextUndoHistoryRegistry _textUndoHistoryRegistry;

        public TextUndoHistoryWorkspaceService(ITextUndoHistoryRegistry textUndoHistoryRegistry)
            => _textUndoHistoryRegistry = textUndoHistoryRegistry;

        public bool TryGetTextUndoHistory(Workspace editorWorkspace, ITextBuffer textBuffer, out ITextUndoHistory undoHistory)
        {
            undoHistory = null;

            if (editorWorkspace is not InteractiveWindowWorkspace)
            {
                return false;
            }

            return _textUndoHistoryRegistry.TryGetHistory(textBuffer, out undoHistory);
        }
    }
}
