using System;
using System.IO;
using System.Linq;
using System.Net;


namespace RobvanderWoude
{
	internal class HTMLEscape
	{
		static readonly string progver = "1.01";


		static int Main( string[] args )
		{
			int rc = 0;

			int argumentscount = args.Length;
			if ( Console.IsInputRedirected )
			{
				argumentscount++;
			}
			if ( argumentscount != 1 || args.Contains( "/?" ) )
			{
				return ShowHelp( );
			}

			string unescapedtext = string.Empty;
			if ( Console.IsInputRedirected )
			{
				unescapedtext = Console.In.ReadToEnd( );
			}
			else if ( File.Exists( args[0] ) )
			{
				unescapedtext= File.ReadAllText( args[0] );
			}
			else
			{
				unescapedtext = args[0];
			}
			string escapedtext = WebUtility.HtmlEncode( unescapedtext );
			escapedtext = ConvertHTMLEntities( escapedtext );
			Console.Write( escapedtext );

			return rc;
		}



		static string ConvertHTMLEntities( string input )
		{
			string output = input.Replace( "'", "'" );
			output = output.Replace( "À", "À" );
			output = output.Replace( "&3193;", "Á" );
			output = output.Replace( "Â", "Â" );
			output = output.Replace( "Ã", "Ã" );
			output = output.Replace( "Ä", "Ä" );
			output = output.Replace( "Å", "Å" );
			output = output.Replace( "Æ", "Æ" );
			output = output.Replace( "Ç", "Ç" );
			output = output.Replace( "È", "È" );
			output = output.Replace( "É", "É" );
			output = output.Replace( "Ê", "Ê" );
			output = output.Replace( "Ë", "Ë" );
			output = output.Replace( "Ì", "Ì" );
			output = output.Replace( "Í", "Í" );
			output = output.Replace( "Î", "Î" );
			output = output.Replace( "Ï", "Ï" );
			output = output.Replace( "Ð", "Ð" );
			output = output.Replace( "Ñ", "Ñ" );
			output = output.Replace( "Ò", "Ò" );
			output = output.Replace( "Ó", "Ó" );
			output = output.Replace( "Ô", "Ô" );
			output = output.Replace( "Õ", "Õ" );
			output = output.Replace( "Ö", "Ö" );
			output = output.Replace( "Ø", "Ø" );
			output = output.Replace( "Ù", "Ù" );
			output = output.Replace( "Ú", "Ú" );
			output = output.Replace( "Û", "Û" );
			output = output.Replace( "Ü", "Ü" );
			output = output.Replace( "Ý", "Ý" );
			output = output.Replace( "Þ", "Þ" );
			output = output.Replace( "ß", "ß" );
			output = output.Replace( "à", "à" );
			output = output.Replace( "á", "á" );
			output = output.Replace( "â", "â" );
			output = output.Replace( "ã", "ã" );
			output = output.Replace( "ä", "ä" );
			output = output.Replace( "å", "å" );
			output = output.Replace( "æ", "æ" );
			output = output.Replace( "ç", "ç" );
			output = output.Replace( "è", "è" );
			output = output.Replace( "é", "é" );
			output = output.Replace( "ê", "ê" );
			output = output.Replace( "ë", "ë" );
			output = output.Replace( "ì", "ì" );
			output = output.Replace( "í", "í" );
			output = output.Replace( "î", "î" );
			output = output.Replace( "ï", "ï" );
			output = output.Replace( "ð", "ð" );
			output = output.Replace( "ñ", "ñ" );
			output = output.Replace( "ò", "ò" );
			output = output.Replace( "ó", "ó" );
			output = output.Replace( "ô", "ô" );
			output = output.Replace( "õ", "õ" );
			output = output.Replace( "ö", "ö" );
			output = output.Replace( "ø", "ø" );
			output = output.Replace( "ù", "ù" );
			output = output.Replace( "ú", "ú" );
			output = output.Replace( "û", "û" );
			output = output.Replace( "ü", "ü" );
			output = output.Replace( "ý", "ý" );
			output = output.Replace( "þ", "þ" );
			output = output.Replace( "ÿ", "ÿ" );
			return output;
		}


		public static int ShowHelp( string errorMessage = "" )
		{
			#region Help Text

			/*
			HTMLEscape,  Version 1.00
			Display HTML-escaped input string in console
 
			Usage:  HTMLESCAPE  textfile
 
			   or:  HTMLESCAPE  unescapedstring
 
			   or:  some_program | HTMLESCAPE
 
			Where:  textfile         file containing text to be escaped
			        unescapedstring  string to be escaped
			        some_program     program whose output is to be escaped
 
			Note:   Exit code ("errorlevel") -1 in case of errors, otherwise 0.
	
			Written by Rob van der Woude
			https://www.robvanderwoude.com
			*/

			#endregion Help Text


			#region Error Message

			if ( !string.IsNullOrWhiteSpace( errorMessage ) )
			{
				Console.Error.WriteLine( );
				Console.ForegroundColor = ConsoleColor.Red;
				Console.Error.Write( "ERROR: " );
				Console.ForegroundColor = ConsoleColor.White;
				Console.Error.WriteLine( errorMessage );
				Console.ResetColor( );
			}

			#endregion Error Message


			#region Display Help

			Console.Error.WriteLine( );

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

			Console.Error.WriteLine( "Display HTML-escaped input string in console" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "HTMLESCAPE  textfile" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "   or:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "HTMLESCAPE  unescapedstring" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "   or:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "some_program | HTMLESCAPE" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "textfile" );
			Console.ResetColor( );
			Console.Error.WriteLine( "         file containing text to be escaped" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "        unescapedstring" );
			Console.ResetColor( );
			Console.Error.WriteLine( "  string to be escaped" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "        some_program" );
			Console.ResetColor( );
			Console.Error.WriteLine( "     program whose output is to be escaped" );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Note:   Exit code (\"errorlevel\") -1 in case of errors, otherwise 0." );

			Console.Error.WriteLine( );

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

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

			#endregion Display Help


			return -1;
		}
	}
}