// 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.Undo;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.VisualStudio.Text.Operations;
 
namespace Microsoft.CodeAnalysis.Interactive;
 
[ExportWorkspaceServiceFactory(typeof(IGlobalUndoService), [WorkspaceKind.Interactive]), Shared]
internal sealed class InteractiveGlobalUndoServiceFactory : IWorkspaceServiceFactory
{
    private readonly GlobalUndoService _singleton;
 
    [ImportingConstructor]
    [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public InteractiveGlobalUndoServiceFactory(ITextUndoHistoryRegistry undoHistoryRegistry)
        => _singleton = new GlobalUndoService(undoHistoryRegistry);
 
    public IWorkspaceService CreateService(HostWorkspaceServices workspaceServices)
        => _singleton;
 
    private sealed class GlobalUndoService : IGlobalUndoService
    {
        private readonly ITextUndoHistoryRegistry _undoHistoryRegistry;
 
        public bool IsGlobalTransactionOpen(Workspace workspace)
            => GetHistory(workspace).CurrentTransaction != null;
 
        public GlobalUndoService(ITextUndoHistoryRegistry undoHistoryRegistry)
            => _undoHistoryRegistry = undoHistoryRegistry;
 
        public bool CanUndo(Workspace workspace)
        {
            // only primary workspace supports global undo
            return workspace is InteractiveWindowWorkspace;
        }
 
        public IWorkspaceGlobalUndoTransaction OpenGlobalUndoTransaction(Workspace workspace, string description)
        {
            if (!CanUndo(workspace))
            {
                throw new ArgumentException(EditorFeaturesResources.Given_Workspace_doesn_t_support_Undo);
            }
 
            var textUndoHistory = GetHistory(workspace);
 
            var transaction = textUndoHistory.CreateTransaction(description);
 
            return new InteractiveGlobalUndoTransaction(transaction);
        }
 
        private ITextUndoHistory GetHistory(Workspace workspace)
        {
            var interactiveWorkspace = (InteractiveWindowWorkspace)workspace;
            var textBuffer = interactiveWorkspace.Window.TextView.TextBuffer;
 
            Contract.ThrowIfFalse(_undoHistoryRegistry.TryGetHistory(textBuffer, out var textUndoHistory));
 
            return textUndoHistory;
        }
 
        private sealed class InteractiveGlobalUndoTransaction : IWorkspaceGlobalUndoTransaction
        {
            private readonly ITextUndoTransaction _transaction;
 
            public InteractiveGlobalUndoTransaction(ITextUndoTransaction transaction)
                => _transaction = transaction;
 
            public void AddDocument(DocumentId id)
            {
                // Nothing to do.
            }
 
            public void Commit()
                => _transaction.Complete();
 
            public void Dispose()
                => _transaction.Dispose();
        }
    }
}