public static Library_V3 getFolderStructure_Library(this TM_WebServices tmWebServices, Guid libraryId, TM_GUI_Objects guiObjects)
        {
            // ReSharper disable AccessToModifiedClosure
            //pre-create this mapping since the view retrieval was a massive performance bottle neck
            var allViews = new Dictionary <Guid, View_V3>();

            foreach (var view in tmWebServices.GetViews())
            {
                if (allViews.hasKey(view.viewId))
                {
                    "[getFolderStructure_Library] duplicate viewID: {0} from Library {0}".format(view.viewId, view.libraryId);              // this should be moved into a TM Library health check
                }
                else
                {
                    allViews.Add(view.viewId, view);
                }
            }

            Action <Folder_V3> mapFolderViews = null;

            Func <List <Guid>, List <View_V3> > mapViews =
                (viewGuids) =>
            {
                var views = new List <View_V3>();

                foreach (var viewGuid in viewGuids)
                {
                    var view = allViews[viewGuid];

                    /*// compress view.guidanceItems using guiObjects
                     * view.guidanceItems_Indexes = (from guid in view.guidanceItems
                     *                                                    select guiObjects.get_Index(guid.str()).str()).toList()
                     *                                                        .join(",").remove(" ");
                     * view.guidanceItems.Clear();*/
                    views.add(view);
                }
                return(views);
            };

            // ReSharper disable PossibleNullReferenceException
            // ReSharper disable ImplicitlyCapturedClosure
            mapFolderViews =
                (folder) => {
                var mappedViews = mapViews(folder.views.guids());
                folder.views.Clear();
                folder.views.add(mappedViews);
                foreach (var subFolder in folder.subFolders)
                {
                    mapFolderViews(subFolder);
                }
            };
            Action <List <Folder_V3>, List <Folder_V3> > mapFolders = (folders, parentFolder) =>
            {
                foreach (var folder in folders)
                {
                    parentFolder.add(folder);
                    mapFolderViews(folder);
                }
            };
            Func <Guid, string, Library_V3> mapLibrary =
                (library_Id, libraryName) => {
                var libraryV3 = new Library_V3
                {
                    libraryId = library_Id,
                    name      = libraryName
                };
                mapFolders(tmWebServices.GetFolders(library_Id), libraryV3.subFolders);
                libraryV3.views.add(mapViews(tmWebServices.GetViewsInLibraryRoot(libraryId).guids()));
                libraryV3.guidanceItems = tmWebServices.getGuidanceItemsIds_NotInViews(library_Id);
                return(libraryV3);
            };

            Func <Guid, Library_V3> getLibrary_TreeStructure =
                (id) => {
                var tmLibrary = tmWebServices.GetLibraryById(id);
                if (tmLibrary.isNull())
                {
                    "[in getLibraryFolderStructure] could not find library with id: {0}".error(id);
                    return(null);
                }
                return(mapLibrary(id, tmLibrary.caption));
            };

            return(getLibrary_TreeStructure(libraryId));
            // ReSharper restore PossibleNullReferenceException
            // ReSharper restore ImplicitlyCapturedClosure
            // ReSharper restore AccessToModifiedClosure
        }