// 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.Diagnostics.CodeAnalysis;
using System.Runtime.InteropServices;
using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
using Microsoft.VisualStudio.ComponentModelHost;
using Microsoft.VisualStudio.Editor;
using Microsoft.VisualStudio.OLE.Interop;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.TextManager.Interop;
using Roslyn.Utilities;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation;
 
internal abstract partial class AbstractOleCommandTarget : IOleCommandTarget
{
    /// <summary>
    /// This is set only during Exec. Currently, this is required to disambiguate the editor calls to
    /// <see cref="IVsTextViewFilter.GetPairExtents(int, int, TextSpan[])"/> between GotoBrace and GotoBraceExt commands.
    /// </summary>
    protected uint CurrentlyExecutingCommand { get; private set; }
 
    public AbstractOleCommandTarget(
        IWpfTextView wpfTextView,
        IComponentModel componentModel)
    {
        Contract.ThrowIfNull(wpfTextView);
        Contract.ThrowIfNull(componentModel);
 
        WpfTextView = wpfTextView;
        ComponentModel = componentModel;
    }
 
    public IComponentModel ComponentModel { get; }
 
    public IVsEditorAdaptersFactoryService EditorAdaptersFactory
    {
        get { return ComponentModel.GetService<IVsEditorAdaptersFactoryService>(); }
    }
 
    /// <summary>
    /// The IWpfTextView that this command filter is attached to.
    /// </summary>
    public IWpfTextView WpfTextView { get; }
 
    /// <summary>
    /// The next command target in the chain. This is set by the derived implementation of this
    /// class.
    /// </summary>
    [DisallowNull]
    protected internal IOleCommandTarget? NextCommandTarget { get; set; }
 
    internal AbstractOleCommandTarget AttachToVsTextView()
    {
        var vsTextView = EditorAdaptersFactory.GetViewAdapter(WpfTextView);
        Contract.ThrowIfNull(vsTextView);
 
        // Add command filter to IVsTextView. If something goes wrong, throw.
        var returnValue = vsTextView.AddCommandFilter(this, out var nextCommandTarget);
        Marshal.ThrowExceptionForHR(returnValue);
        Contract.ThrowIfNull(nextCommandTarget);
 
        NextCommandTarget = nextCommandTarget;
 
        return this;
    }
 
    protected virtual ITextBuffer? GetSubjectBufferContainingCaret()
        => WpfTextView.GetBufferContainingCaret();
 
    protected virtual ITextView ConvertTextView()
        => WpfTextView;
}