HTML TO PHP.cs

using HtmlAgilityPack;
using System;
using System.IO;
using System.Linq;
using System.Threading;

namespace HTML_to_PHP
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Press <Enter> key to continue...");
            while (Console.ReadKey().Key != ConsoleKey.Enter)
            {
                Console.WriteLine("Press <Enter> key to continue...");
            }
            
            var currentDir = Environment.CurrentDirectory;
            var rootDir = System.IO.Path.GetFullPath($"{currentDir}/live-new/");
            if (Directory.Exists(rootDir))
            {
                //var files = Directory.GetFiles(rootDir);
                var files = Directory.GetFiles(rootDir, "*.html", SearchOption.AllDirectories);
                //var files = Directory.GetFileSystemEntries(rootDir, "*.html", SearchOption.AllDirectories); //not working
                var i = 0;
                foreach (var file in files)
                {
                    var currentSubDir = file.Replace(rootDir, "");

                    // evaluate the directory level of the current file being modified so that we can add appropriate number of ellipses in the path to navigate to the root dir 
                    var dirLevel = Helper.CountSubstring(currentSubDir, "\\");
                    var navigateDir = dirLevel > 0 ? string.Concat(Enumerable.Repeat("../", dirLevel)) : "";

                    var htmlDoc = new HtmlDocument();
                    htmlDoc.LoadHtml(System.IO.File.ReadAllText(file));

                    var nav = htmlDoc.DocumentNode.SelectSingleNode("//nav");//.SelectNodes("//*[@id=\"my_control_id\"]");
                    nav.ParentNode.ReplaceChild(HtmlNode.CreateNode($"<?php include('{navigateDir}partials/main-nav.php') ?>"), nav);
                    bool success = false;
                    using (System.IO.StreamWriter newFile = new System.IO.StreamWriter(file.Replace(".html", ".php"), true))
                    {

                        try { htmlDoc.Save(newFile); success = true; }
                        catch (Exception) { throw; }
                        ////string text = System.IO.File.ReadAllText(file);
                        //string[] lines = //System.IO.File.ReadAllLines(file);
                        //foreach (string line in lines)
                        //{
                        //    // Use a tab to indent each line of the file.
                        //    //Console.WriteLine("\n" + line);
                        //    newFile.WriteLine(line);
                        //}
                    }

                    if (success)
                    {
                        //File.Move(file, file.Replace(".html", ".html.bak"));
                        Console.Write("\r{0} Files Updated...", ++i);
                        Thread.Sleep(300);
                    }
                }
            }
            
            Console.WriteLine("Done...");
            Console.ReadKey();
        }
    }

    static class Helper
    {
        public static int CountSubstring(this string text, string value)
        {
            int count = 0, minIndex = text.IndexOf(value, 0);
            while (minIndex != -1)
            {
                minIndex = text.IndexOf(value, minIndex + value.Length);
                count++;
            }
            return count;
        }
    }
}