// 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.Runtime.InteropServices;
using Microsoft.CodeAnalysis.Workspaces.ProjectSystem;
using Microsoft.VisualStudio.Shell.Interop;
using Microsoft.VisualStudio.TextManager.Interop;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.LanguageService;
 
internal abstract partial class AbstractLanguageService<TPackage, TLanguageService> : IVsContainedLanguageFactory
{
    private ProjectSystemProject FindMatchingProject(IVsHierarchy hierarchy, uint itemid)
    {
        // Here we must determine the project that this file's document is to be a part of.
        // Venus creates a separate Project for a .aspx or .ascx file, and so we must associate
        // the document with that Project. We first query through a Venus-specific interface,
        // and if that fails we then use a general interface which is provided for non-Venus
        // contained language hosts (such as workflow editors.) This ordering is critical: in
        // Sharepoint projects (which are flavored workflow projects), we must prefer the
        // item-specific answer given to us from Venus rather than the project-level answer
        // given, which are going to be different. This was changed for Dev10 bug 839428.
        string projectName = null;
        if (this.SystemServiceProvider.GetService(typeof(SWebApplicationCtxSvc)) is IWebApplicationCtxSvc webApplicationCtxSvc)
        {
            if (webApplicationCtxSvc.GetItemContext(hierarchy, itemid, out var webServiceProvider) >= 0)
            {
                var webFileCtxServiceGuid = typeof(IWebFileCtxService).GUID;
                if (webServiceProvider.QueryService(ref webFileCtxServiceGuid, ref webFileCtxServiceGuid, out var service) >= 0)
                {
                    try
                    {
                        var webFileCtxService = Marshal.GetObjectForIUnknown(service) as IWebFileCtxService;
                        webFileCtxService.GetIntellisenseProjectName(out projectName);
                    }
                    finally
                    {
                        if (service != IntPtr.Zero)
                        {
                            Marshal.Release(service);
                        }
                    }
                }
            }
        }
 
        if (string.IsNullOrEmpty(projectName))
        {
            if (hierarchy is IVsContainedLanguageProjectNameProvider containedLanguageProjectNameProvider)
            {
                containedLanguageProjectNameProvider.GetProjectName(itemid, out projectName);
            }
        }
 
        if (string.IsNullOrEmpty(projectName))
        {
            return null;
        }
 
        return this.Workspace.GetProjectWithHierarchyAndName(hierarchy, projectName);
    }
 
    public int GetLanguage(IVsHierarchy hierarchy, uint itemid, IVsTextBufferCoordinator bufferCoordinator, out IVsContainedLanguage language)
    {
        var project = FindMatchingProject(hierarchy, itemid);
        if (project == null)
        {
            language = null;
            return VSConstants.E_INVALIDARG;
        }
 
        language = CreateContainedLanguage(bufferCoordinator, project, hierarchy, itemid);
 
        return VSConstants.S_OK;
    }
}