using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows.Forms;



namespace RobvanderWoude
{
	class ListIntCmd
	{
		public static string progver = "1.07";


		[STAThreadAttribute]
		static int Main( string[] args )
		{
			#region Initialize variables

			int rc = 0;
			string separartor = Environment.NewLine;
			bool separatorset = false;
			bool copy = false;
			bool copyset = false;
			bool logging = false;
			bool logset = false;
			string logdir = Directory.GetParent( System.Reflection.Assembly.GetEntryAssembly( ).Location ).ToString( ); // This program's parent folder
			string logfile = Path.Combine( logdir, "ListIntCmd.log" );
			bool logfileset = false;
			string logtext = String.Empty;
			DateTime logbegin;
			DateTime logend;

			#endregion Initialize variables


			#region Command Line Parsing

			if ( args.Length > 0 )
			{
				foreach ( string arg in args )
				{
					switch ( arg.Substring( 0, Math.Min( 2, arg.Length ) ).ToUpper( ) )
					{

						case "/?":
							return ShowHelp( );
						case "/C":
							if ( copyset )
							{
								return ShowHelp( "Duplicate command line switch /C" );
							}
							copy = true;
							copyset = true;
							break;
						case "/L":
							if ( logset )
							{
								return ShowHelp( "Duplicate command line switch /L" );
							}
							logging = true;
							logset = true;
							if ( arg.Length > 4 && arg[2] == ':' )
							{
								logfile = Environment.ExpandEnvironmentVariables( arg.Substring( 3 ).Trim( "\" ".ToCharArray( ) ) );
								logdir = Directory.GetParent( logfile ).ToString( );
								logfileset = true;
							}
							break;
						default:
							if ( separatorset )
							{
								return ShowHelp( );
							}
							// Translate:               \n to linefeed,                       \t to tab,             \/ to slash,          \\ to backslash, escaped \n to literal \n, escaped \t to literal \t
							separartor = arg.Replace( "\\n", Environment.NewLine ).Replace( "\\t", "\t" ).Replace( "\\/", "/" ).Replace( "\\\\", "\\" ).Replace( "\\\n", "\\n" ).Replace( "\\\t", "\\t" );
							separatorset = true;
							break;
					}
				}
			}

			if ( logfileset && !String.IsNullOrEmpty( logfile ) )
			{
				if ( !Directory.Exists( logdir ) )
				{
					return ShowHelp( string.Format( "Invalid log path \"{0}\"", logdir ) );
				}
			}

			#endregion Command Line Parsing


			try
			{
				string comspec = Environment.GetEnvironmentVariable( "COMSPEC" );

				logbegin = DateTime.Now;
				logtext += string.Format( "ListIntCmd.exe,  Version {0}{1}", progver, Environment.NewLine );
				logtext += string.Format( "{0}{1}", Environment.OSVersion.VersionString, Environment.NewLine );
				logtext += string.Format( "Search started at {0}{1}{1}", logbegin.ToString( "yyyy-MM-dd, HH:mm:ss.fff" ), Environment.NewLine );
				logtext += string.Format( "COMSPEC=\"{0}, ProductVersion={1}\"{2}{2}", comspec, FileVersionInfo.GetVersionInfo( comspec ).ProductVersion, Environment.NewLine );

				StreamReader file = new StreamReader( comspec, Encoding.ASCII );
				string content = file.ReadToEnd( );
				file.Close( );
				
				string pattern = @"c\0m\0d\0\.\0e\0x\0e\0[\w\W]*?\(c\)";
				if ( Regex.IsMatch( content, pattern ) )
				{
					content = Regex.Match( content, pattern ).ToString( );
				}

				List<string> intcmds = new List<string>( ) { "CD", "DATE", "GOTO", "KEYS", "REM", "TIME" }; // preload internal commands that are skipped by our previous -- too tight -- RegEx pattern
				logtext += string.Format( "{0}Preloaded internal commands:{0}{0}{1}{0}{0}", Environment.NewLine, string.Join( Environment.NewLine, intcmds.ToArray( ) ) );
				// extended exclusion string for Windows 2000..10; the longer the exclusion string, the higher the risk that some new future internal command will be omited in the output
				string excludestr = "BAT,CMD,COM,DISABLEDELAYEDEXPANSION,DLL,EQU,EXE,GEQ,GTR,HH,JS,LEQ,LSS,MM,MSC,NEQ,NTDLL,SM,VBS,VERSION,VS,WS";
				string[] excludearr = excludestr.Split( ",".ToCharArray( ) );
				List<string> exclude = new List<string>( excludearr ); // Optimized for .NET Framework 2.0; in .NET Framework 3.5+ we might have used List<string> exclude = excludestr.Split( ",".ToCharArray( ) ).ToList<string>( );

				pattern = @"([A-Z]\0){2,}";
				Regex regex = new Regex( pattern );
				if ( regex.IsMatch( content ) )
				{
					logtext += string.Format( "{0}List of regex matches:{0}", Environment.NewLine );
					foreach ( Match match in regex.Matches( content ) )
					{
						string line = String.Empty;
						string intcmd = match.ToString( ).Replace( "\0", string.Empty );
						line += string.Format( "{0}{1,-24}", Environment.NewLine, intcmd );
						if ( exclude.Contains( intcmd ) )
						{
							line += string.Format( "\texcluded by exlusion list", intcmd );
						}
						else if ( intcmds.Contains( intcmd ) )
						{
							line += string.Format( "\tskipped duplicate", intcmd );
						}
						else
						{
							intcmds.Add( intcmd );
							line += string.Format( "\tadded to the list of internal commands", intcmd );
						}
						logtext += line.TrimEnd( );
					}
					logtext += string.Format( "{0}{0}{0}Results so far:{0}{0}{1}{0}{0}", Environment.NewLine, String.Join( Environment.NewLine, intcmds.ToArray( ) ) );
					intcmds.Sort( );
					logtext += string.Format( "{0}Results after sorting:{0}{0}{1}{0}{0}", Environment.NewLine, String.Join( Environment.NewLine, intcmds.ToArray( ) ) );
				}

				// Return a default list if we could not find the internal commands in %COMSPEC%
				if ( intcmds.Count == 0 )
				{
					logtext += string.Format( "{0}Using default, hard-coded list{0}{0}", Environment.NewLine );
					string defintcmdsstr = "ASSOC,BREAK,CALL,CD,CHDIR,CLS,COLOR,COPY,DATE,DEL,DIR,DPATH,ECHO,ENDLOCAL,ERASE,EXIT,FOR,FTYPE,GOTO,IF,KEYS,MD,MKDIR,MKLINK,MOVE,PATH,PAUSE,POPD,PROMPT,PUSHD,RD,REM,REN,RENAME,RMDIR,SET,SETLOCAL,SHIFT,START,TIME,TITLE,TYPE,VER,VERIFY,VOL";
					string[] defintcmdsarr = defintcmdsstr.Split( ",".ToCharArray( ), StringSplitOptions.RemoveEmptyEntries );
					intcmds = new List<string>( defintcmdsarr ); // Optimized for .NET Framework 2.0; in .NET Framework 3.5+ we might have used List<string> intcmds = defintcmdsstr.Split( ",".ToCharArray( ) ).ToList<string>( );
					rc = 2;
				}

				string result = String.Join( separartor, intcmds.ToArray( ) );

				Console.Write( result );

				if ( copy )
				{
					logtext += string.Format( "Writing result to clipboard . . .{0}{0}", Environment.NewLine );
					Clipboard.SetText( result );
					logtext += string.Format( "Text written to clipboard:{1}{1}{0}{1}{1}", Clipboard.GetText( ), Environment.NewLine );
				}

				if ( logging )
				{
					logend = DateTime.Now;
					TimeSpan duration = logend - logbegin;
					logtext += string.Format( "Search ended at {0} ({1:N0} milliseconds){2}", logend.ToString( "yyyy-MM-dd, HH:mm:ss.fff" ), duration.TotalMilliseconds, Environment.NewLine );
					StreamWriter logstream = new StreamWriter( logfile );
					logstream.Write( logtext );
					logstream.Close( );
				}

				return rc;
			}
			catch ( Exception e )
			{
				return ShowHelp( e.Message );
			}
		}


		#region Error Handling

		public static int ShowHelp( params string[] errmsg )
		{
			#region Error Message

			if ( errmsg.Length > 0 )
			{
				List<string> errargs = new List<string>( errmsg );
				errargs.RemoveAt( 0 );
				Console.Error.WriteLine( );
				Console.ForegroundColor = ConsoleColor.Red;
				Console.Error.Write( "ERROR:\t" );
				Console.ForegroundColor = ConsoleColor.White;
				Console.Error.WriteLine( errmsg[0], errargs.ToArray( ) );
				Console.ResetColor( );
			}

			#endregion Error Message


			#region Help Text

			/*
			ListIntCmd.exe,  Version 1.07
			List all available internal commands

			Usage:  LISTINTCMD  [ "separator" ]  [ /C ]  [ /L[:logfile] ]

			Where:  separator     is the character or string used to separate the
			                      command names in the output (default: linefeed)
			        /C            Copies output to clipboard
			        /L[:logfile]  Logs the entire search process to logfile
			                      (default log file name and location:
			                      ListIntCmd.log in program's parent folder)

			Notes:  Use doublequotes if separator contains spaces or "special" characters.
			        separator accepts \n for linefeeds, \t for tabs, \/ for slashes,
			        \\ for backslashes, and """" for doublequotes.
			        Return code 2 if commands could not be retrieved and default list
			        had to be returned instead, 1 on other errors, 0 if all is well.

			Written by Rob van der Woude
			https://www.robvanderwoude.com
			*/

			#endregion Help Text


			#region Display Help Text

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "ListIntCmd.exe,  Version {0}", progver );

			Console.Error.WriteLine( "List all available internal commands" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "LISTINTCMD  [ \"separator\" ]  [ /C ]  [ /L[:logfile] ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "separator" );
			Console.ResetColor( );
			Console.Error.WriteLine( "     is the character or string used to separate the" );

			Console.Error.WriteLine( "                      command names in the output (default: linefeed)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "        /C            C" );
			Console.ResetColor( );
			Console.Error.WriteLine( "opies output to clipboard" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "        /L[:logfile]  L" );
			Console.ResetColor( );
			Console.Error.Write( "ogs the entire search process to " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "logfile" );
			Console.ResetColor( );

			Console.Error.WriteLine( "                      (default log file name and location:" );

			Console.Error.WriteLine( "                      ListIntCmd.log in program's parent folder)" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Notes:  Use doublequotes if " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "separator" );
			Console.ResetColor( );
			Console.Error.WriteLine( " contains spaces or \"special\" characters." );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "        separator" );
			Console.ResetColor( );
			Console.Error.Write( " accepts " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "\\n" );
			Console.ResetColor( );
			Console.Error.Write( " for linefeeds, " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "\\t" );
			Console.ResetColor( );
			Console.Error.Write( " for tabs, " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "\\/" );
			Console.ResetColor( );
			Console.Error.WriteLine( " for slashes," );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "        \\\\" );
			Console.ResetColor( );
			Console.Error.Write( " for backslashes, and " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "\"\"\"\"" );
			Console.ResetColor( );
			Console.Error.WriteLine( " for doublequotes." );

			Console.Error.WriteLine( "        Return code 2 if commands could not be retrieved and default list" );

			Console.Error.WriteLine( "        had to be returned instead, 1 on other errors, 0 if all is well." );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Written by Rob van der Woude" );

			Console.Error.WriteLine( "https://www.robvanderwoude.com" );

			#endregion Display Help Text


			return 1;
		}

		#endregion Error Handling
	}
}