Bulk update documents with their default template in case they have no template assigned

FixNodeswithoutTemplates.cs

using System.Linq;
using System.Reflection;
using Umbraco.Core;
using Umbraco.Core.Logging;
using Umbraco.Core.Models;
using Umbraco.Web;

namespace DotSee.Common
{
    public class FixNodesWithoutTemplates : ApplicationEventHandler
    {
        protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            base.ApplicationStarted(umbracoApplication, applicationContext);

            //Get a reference to the Content Type Service - we will use it to find the default template for the doctype
            var cts = ApplicationContext.Current.Services.ContentTypeService;

            //Get a reference to the Content Service - we will use it to update each document with its default template
            var cs = ApplicationContext.Current.Services.ContentService;

            //Get all content types so that we have a cached version of this to use in the foreach loop
            var contentTypes = cts.GetAllContentTypes();

            LogHelper.Info(MethodBase.GetCurrentMethod().DeclaringType, "Getting list of nodes that do not have a template specified...");

            //Get all documents from all roots that do not have a template defined
            foreach (IPublishedContent item in
                new UmbracoHelper(UmbracoContext.Current)
                    .TypedContentAtRoot()
                    .SelectMany(x => x.Descendants())
                    .Where(y => string.IsNullOrEmpty(y.GetTemplateAlias())))
            {

                //Get the document type (use the in-memory contentTypes enumerable instead of getting the content type of each doc)
                IContentType ct = contentTypes.Where(x => x.Alias == item.ContentType.Alias).FirstOrDefault(); 
                
                //Get the default template for the document type
                ITemplate t = ct.DefaultTemplate;

                //If there is no default document, log it and move on
                if (t == null)
                {
                    LogHelper.Warn(item.GetType(), string.Format("Item '{0}' of type '{1}' did not have a default template", item.Name, item.DocumentTypeAlias));
                    continue;
                }

                //Create an IContent which we will update with the new template
                IContent c = cs.GetById(item.Id);

                //Set the template
                c.Template = t;

                //Publish our updated document
                cs.SaveAndPublishWithStatus(c);

                LogHelper.Info(item.GetType(), string.Format("Item '{0}' of type '{1}' had its template changed to '{2}'", item.Name, item.DocumentTypeAlias, t.Alias));
            }
        }
    }
}