zipping files to result.zip or extracting files from archive

using System;
using System.IO;
using System.IO.Compression;

namespace ConsoleApplication {

    /*
    links to online source code listing: last updated 6/4/2019
      + https://gist.github.com/kyrathasoft/bdebc9ad97941e35abdde146bbf2d73b
      + https://pastebin.com/QYFZXEkq
    */

    class Program{

        static bool blnExit = false;
        static string startPath = @".\start";
        static string zipPath = @".\result.zip";
        static string extractPath = @".\extract";


        static void Main(string[] args){

            ShowTitle();
            if(Init()){
                Console.WriteLine("\n Program initialization succeeded.");
                /* Because Init() succeeded, we know that:
                   (1) there's a /start subdir with at least one file
                   (2) there's NOT a result.zip file in the EXE's dir
                   (3) there's an /extract subdir that is empty
                */
                while(!blnExit){
                    BuildMenu();
                }

                Console.WriteLine("\n Program exits...\n");
            }
        }

        public static void BuildMenu(){
            Console.WriteLine("\n\n     Menu:");
            if(StartSubdirExistsWithOneOrMoreFiles() && ZipArchiveResultFileDoesntExist()){
                Console.WriteLine("       (Z)ip start subdir files to result.zip");
            }
            if(File.Exists("result.zip")){
                Console.WriteLine("      (E)xtract result.zip to .\\extract subdirectory");
                Console.WriteLine("       Extract (O)nly 'Program.cs to .\\extract sudirectory");
                Console.WriteLine("       (D)oes file 'MainForm.cs' exist in archive?");
                if(!ZipArchiveContainsThisFile("result.zip", "MyNameIs.txt")){
                    Console.WriteLine("       D(y)namically add name/b-day to archive as entry 'MyNameIs.txt'");
                }
            }

            Console.WriteLine("       E(x)it Program");
            Console.Write("           Your selection > ");
            ConsoleKeyInfo cki = Console.ReadKey();
            switch(cki.Key){
                case ConsoleKey.Z:
                    ZipFile.CreateFromDirectory(startPath, zipPath);
                    SeeIfExtractDirExistsAndDeleteItsFiles();
                    break;
                case ConsoleKey.D:
                    if(ZipArchiveContainsThisFile("result.zip", "MainForm.cs")){
                        Console.WriteLine("\n          Yes, 'MainForm.cs' is contained in result.zip.");
                    }else{
                        Console.WriteLine("\n          No, the program didn't find 'MainForm.cs' in result.zip.");
                    }
                    break;
                case ConsoleKey.E:
                    extractPath = SanitizeExtractPath(extractPath);
                    ZipFile.ExtractToDirectory(zipPath, extractPath);
                    SeeIfZippedArchiveExistsIfSoDelete();
                    break;
                case ConsoleKey.O:
                    extractPath = SanitizeExtractPath(extractPath);
                    using (ZipArchive archive = ZipFile.OpenRead(zipPath)){
                        foreach (ZipArchiveEntry entry in archive.Entries){
                            string fname = entry.FullName;
                            if(fname.Contains("Program.cs")){
                                //Console.WriteLine("\n Found 'Program.cs'...");
                                string destinationPath = Path.GetFullPath(Path.Combine(extractPath, entry.FullName));
                                Console.WriteLine("\n Dest. path: {0}", destinationPath);
                                entry.ExtractToFile(destinationPath);
                            }
                        }
                    }
                    break;
                case ConsoleKey.Y:
                    using (FileStream zipToOpen = new FileStream(@".\result.zip", FileMode.Open))
                    {
                        using (ZipArchive archive = new ZipArchive(zipToOpen, ZipArchiveMode.Update))
                        {
                            ZipArchiveEntry readmeEntry = archive.CreateEntry("MyNameIs.txt");
                            using (StreamWriter writer = new StreamWriter(readmeEntry.Open()))
                            {
                                    writer.WriteLine("My name is Bryan Miller.");
                                    writer.WriteLine("The date: {0}", DateTime.Now.ToString());
                            }
                            Console.WriteLine("\n       Successfully added 'MyNameIs.txt' to 'result.zip'");
                        }
                    }
                    break;
                default:
                    blnExit = true;
                    break;
            }
        }

        public static bool Init(){
            bool success = false;
            if(SeeIfZippedArchiveExistsIfSoDelete()){
                if(SeeIfExtractDirExistsAndDeleteItsFiles()){
                    if(SeeIfStartDirExistsAndContainsFilesToBeZipped()){
                        success = true;
                    }
                }
            }

            return success;
        }

        public static string SanitizeExtractPath(string p){
            string result = p;

            result = Path.GetFullPath(result);
            if (!result.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal)){
                result += Path.DirectorySeparatorChar;
            }

            return p;
        }

        public static bool ZipArchiveResultFileDoesntExist(){
            bool result = false;
            if(!File.Exists("result.zip")){ result = true;}
            return result;
        }

        public static bool ZipArchiveContainsThisFile(string _archive, string _filename_in_question){
                bool result = false;
                if(!File.Exists(_archive)){
                    //control falls through; false is returned...
                }else{
                    using(ZipArchive archive = ZipFile.OpenRead(_archive)){
                        foreach(ZipArchiveEntry entry in archive.Entries){
                            string filename = Path.GetFileName(entry.FullName);
                            if(filename == _filename_in_question){
                                result = true;
                                break;
                            }
                        }
                    }
                }
                return result;
        }

        public static bool StartSubdirExistsWithOneOrMoreFiles(){
            bool result = false;

            if(Directory.Exists(@".\start")){
                string[] files = Directory.GetFiles(@".\start", "*.*", SearchOption.TopDirectoryOnly);
                if(files.Length > 0){
                    result = true;
                }
            }

            return result;
        }

        public static bool SeeIfZippedArchiveExistsIfSoDelete(){
            bool success = false;
            if(File.Exists("result.zip")){
                try{
                    File.Delete("result.zip");
                    success = true;
                }catch{
                    Console.WriteLine("\n Unable to delete result.zip during initialization.");
                }
            }else{ success = true; }
            return success;
        }

        public static bool SeeIfExtractDirExistsAndDeleteItsFiles(){
            bool success = false;
            if(Directory.Exists(@".\extract")){
                string[] files = Directory.GetFiles(@".\extract", "*.*", SearchOption.TopDirectoryOnly);
                if(files.Length > 0){
                    try{
                        for(int i=0; i < files.Length; i++){
                            File.Delete(files[i]);
                        }
                        success = true;
                    }catch{
                        Console.WriteLine("\n Unable to delete files in .\\extract during initialization.");
                    }
                }else{ success = true; }
            }else{
                Directory.CreateDirectory(@".\extract");
                success = true;
            }
            return success;
        }

        public static bool SeeIfStartDirExistsAndContainsFilesToBeZipped(){
            bool success = false;
            if(!Directory.Exists(@".\start")){
                Console.WriteLine("\n Missing .\\start subdirectory with files to be zipped.");
                Console.WriteLine(" Program will terminate.\n");
            }else{
                //directory exists, but does it contain one or more files to be zipped?
                string[] files = Directory.GetFiles(@".\start", "*.*", SearchOption.TopDirectoryOnly);
                if(files.Length < 1){
                    Console.WriteLine("\n Subdirectory .\\start doesn't have any files to be zipped.");
                    Console.WriteLine(" Program will terminate.\n");
                }else{

                    success = true;
                }
            }
            return success;
        }

        public static void ShowTitle(){
            Console.Clear();
            Console.ForegroundColor = ConsoleColor.Yellow;
            Console.WriteLine("\n running 'simple.exe'...");
            Console.ForegroundColor = ConsoleColor.Gray;
            Console.WriteLine(" kyrathasoft@gmail.com, 6/02/2019");
            Console.ForegroundColor = ConsoleColor.White;
        }

    }
}