using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;


namespace RobvanderWoude
{
	internal class Count
	{
		static readonly string progver = "1.00";


		static int Main( string[] args )
		{
			bool quietmode = false;
			int count = 0;
			string filter = string.Empty;
			SearchOption searchoption = SearchOption.TopDirectoryOnly;


			if ( args.Contains( "/?" ) )
			{
				return ShowHelp( );
			}

			foreach ( string arg in args )
			{
				if ( arg[0] == '/' )
				{
					if ( arg.ToUpper( ) == "/Q" )
					{
						if ( quietmode )
						{
							return ShowHelp( "Duplicate command line switch /Q" );
						}
						quietmode = true;
					}
					else if ( arg.ToUpper( ) == "/S" && !Console.IsInputRedirected )
					{
						if ( searchoption == SearchOption.AllDirectories )
						{
							return ShowHelp( "Duplicate command line switch /S" );
						}
						searchoption = SearchOption.AllDirectories;
					}
					else
					{
						return ShowHelp( "Invalid command line switch {0}", arg );
					}
				}
				else
				{
					if ( !string.IsNullOrWhiteSpace( filter ) )
					{
						if ( Console.IsInputRedirected )
						{
							return ShowHelp( "Duplicate filter specification" );
						}
						else
                        {
							return ShowHelp( "Duplicate file specification" );
						}
					}
					filter = arg;
				}
			}


			if ( Console.IsInputRedirected )
			{
				while ( Console.In.Peek( ) != -1 )
				{
					string line = Console.ReadLine( );
					if ( line.Contains( filter ) )
					{
						count++;
					}
				}
			}
			else
			{
				if ( args.Length == 0 )
				{
					return ShowHelp( );
				}

				try
				{
					string dir = Directory.GetParent( filter ).FullName;
					string files = Path.GetFileName( filter );
					if ( Directory.Exists( filter ) )
					{
						dir = Path.GetFullPath( filter );
						files = "*.*";
					}
					count = Directory.GetFiles( dir, files, searchoption ).Length;
				}
				catch( Exception e )
				{
					return ShowHelp( e.Message );
				}
			}

			if ( !quietmode )
			{
				Console.WriteLine( count );
			}

			return count;
		}


		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

			/*
			Count.exe,  Version 1.00
			Count specified objects and return result as errorlevel

			Usage:    Count.exe  filespec  [ /S ]  [ /Q ]

			   or:    some_prog  |  Count.exe  [ filter ]  [ /Q ]

			Where:    filespec      specifies files to be counted (default: *.*)
			          some_prog     program whose output is to be counted (all lines)
			          filter        filter for some_prog (count lines containing filter)
			          /Q            Quiet mode: no screen output
			          /S            recursive (include Subdirectories)

			Examples:
			=========
			
			Count number of *.exe files in C:\Windows\System32 and subdirectories:
			Count.exe C:\Windows\System32\*.exe /S

			Count number of subdirectories in C:\Windows\System32:
			DIR /AD /B /S C:\Windows\System32 | Count.exe

			Count number of environment variables:
			SET | Count.exe "="
			
			Notes:    Instead of Count.exe, one could use Windows' native FIND.EXE
			          with its /C switch in a FOR /F loop, but Count.exe may make
			          your batch code easier to read by using SET Count=%ErrorLevel%
			          Count.exe returns the number of (matching) lines, not the
			          number of occurrences of the specified filter string.
			          Count result is displayed on screen and returned as errorlevel;
			          both are limited to 32-bit integer values.
			          Return code (\"ErrorLevel\") equals count result, or -1 for
			          (command line) errors.

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

			#endregion Help Text


			#region Display Help Text

			Console.Error.WriteLine( );

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

			Console.Error.WriteLine( "Count specified objects and return result as errorlevel" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "Count.exe  filespec  [ /S ]  [ /Q ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "   or:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "some_prog  |  Count.exe  [ filter ]  [ /Q ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "filespec" );
			Console.ResetColor( );
			Console.Error.WriteLine( "      specifies files to be counted (default: *.*)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          some_prog" );
			Console.ResetColor( );
			Console.Error.WriteLine( "     program whose output is to be counted (all lines)" );
			
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          filter" );
			Console.ResetColor( );
			Console.Error.WriteLine( "        filter for some_prog (count lines containing filter)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /Q            Q" );
			Console.ResetColor( );
			Console.Error.WriteLine( "uiet mode: no screen output" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /S" );
			Console.ResetColor( );
			Console.Error.Write( "            recursive (include " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "S" );
			Console.ResetColor( );
			Console.Error.WriteLine( "ubdirectories)" );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Examples:" );

			Console.Error.WriteLine( "=========" );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Count number of *.exe files in C:\\Windows\\System32 and subdirectories:" );

			Console.ForegroundColor = ConsoleColor.Green;
			Console.Error.WriteLine( "Count.exe C:\\Windows\\System32\\*.exe /S" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Count number of subdirectories in C:\\Windows\\System32:" );

			Console.ForegroundColor = ConsoleColor.Green;
			Console.Error.WriteLine( "DIR /AD /B /S C:\\Windows\\System32 | Count.exe" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Count number of environment variables:" );

			Console.ForegroundColor = ConsoleColor.Green;
			Console.Error.WriteLine( "SET | Count.exe \"=\"" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Notes:    Instead of Count.exe, one could use Windows' native FIND.EXE" );

			Console.Error.WriteLine( "          with its /C switch in a FOR /F loop, but Count.exe may make" );

			Console.Error.Write( "          your batch code easier to read, by using " );
			Console.ForegroundColor = ConsoleColor.Green;
			Console.Error.WriteLine( "SET Count=%ErrorLevel%" );
			Console.ResetColor( );

			Console.Error.WriteLine( "          Count.exe returns the number of (matching) lines, not the" );

			Console.Error.WriteLine( "          number of occurrences of the specified filter string." );

			Console.Error.WriteLine( "          Count result is displayed on screen and returned as errorlevel;" );

			Console.Error.WriteLine( "          both are limited to 32-bit integer values." );

			Console.Error.WriteLine( "          Return code (\"ErrorLevel\") equals count result, or -1 for" );

			Console.Error.WriteLine( "          (command line) errors." );

			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;
		}

	}
}