// 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 Microsoft.VisualStudio.OLE.Interop;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.TextManager.Interop;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.Venus;
 
internal partial class ContainedLanguage : IVsContainedLanguage
{
    public int GetColorizer(out IVsColorizer colorizer)
    {
        // We have no legacy colorizer, and so we'll return E_NOTIMPL to opt out of using one
        colorizer = null;
        return VSConstants.E_NOTIMPL;
    }
 
    public int GetLanguageServiceID(out Guid guidLangService)
    {
        guidLangService = _languageServiceGuid;
        return VSConstants.S_OK;
    }
 
    public int GetTextViewFilter(
        IVsIntellisenseHost intellisenseHost,
        IOleCommandTarget nextCmdTarget,
        out IVsTextViewFilter textViewFilter)
    {
        var wpfTextView = GetViewFromIVsIntellisenseHost(intellisenseHost);
 
        if (wpfTextView == null)
        {
            textViewFilter = null;
            return VSConstants.E_FAIL;
        }
 
        textViewFilter = new VenusCommandFilter(wpfTextView, SubjectBuffer, nextCmdTarget, ComponentModel);
 
        return VSConstants.S_OK;
    }
 
    private IWpfTextView GetViewFromIVsIntellisenseHost(IVsIntellisenseHost intellisenseHost)
    {
        // The easiest way (unfortunately) is to get do reflection to get the view from the IVsIntellisenseHost.
        // In practice, the implementations we care about of this are just shim implementations from the editor.
        // The only alternative way to do this is to do very complicated watching of ITextView and IVsTextView
        // lifetimes to correlate them, but that requires running code in those code paths for all views which
        // seems a bit overkill for our needs.
        var field = intellisenseHost.GetType().GetField("_simpleTextViewWindow", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
        if (field == null)
        {
            return null;
        }
 
        if (field.GetValue(intellisenseHost) is not IVsTextView view)
        {
            return null;
        }
 
        return _editorAdaptersFactoryService.GetWpfTextView(view);
    }
 
    public int Refresh(uint refreshMode)
        => VSConstants.S_OK;
 
    public int SetBufferCoordinator(IVsTextBufferCoordinator pBC)
    {
        BufferCoordinator = pBC;
        return VSConstants.S_OK;
    }
 
    public int SetHost(IVsContainedLanguageHost host)
    {
        if (ContainedDocument.ContainedLanguageHost == host)
        {
            return VSConstants.S_OK;
        }
 
        ContainedDocument.ContainedLanguageHost = host;
 
        // Are we going away due to the contained language being disconnected?
        if (host == null)
        {
            OnDisconnect();
        }
 
        return VSConstants.S_OK;
    }
 
    public int WaitForReadyState()
        => VSConstants.S_OK;
}