using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;


namespace RobvanderWoude
{
	class DelTrash
	{
		static string progver = "1.03";


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

			int rc = 0;
			long totalsize = 0;
			int deleteditems = 0;
			int accessdenieddirs = 0;
			bool accessdenied = false;
			bool confirm = false;
			bool listonly = false;
			bool progress = false;
			bool quiet = false;
			bool verbose = false;
			RecycleFlags flags = RecycleFlags.RecycleNoSound;
			string drive = null; // default: All drives
			string windrive = Path.GetPathRoot( Environment.SystemDirectory );

			#endregion Initialize Variables


			#region Parse Command Line

			if ( args.Length > 3 )
			{
				return ShowHelp( );
			}

			foreach ( string arg in args )
			{
				switch ( arg.ToUpper( ) )
				{
					case "/?":
						return ShowHelp( );
					case "/C":
						if ( confirm )
						{
							return ShowHelp( "Duplicate command line switch /C" );
						}
						confirm = true;
						break;
					case "/L":
						if ( listonly )
						{
							return ShowHelp( "Duplicate command line switch /L" );
						}
						listonly = true;
						break;
					case "/P":
						if ( progress )
						{
							return ShowHelp( "Duplicate command line switch /P" );
						}
						progress = true;
						break;
					case "/Q":
						if ( quiet )
						{
							return ShowHelp( "Duplicate command line switch /Q" );
						}
						if ( verbose )
						{
							return ShowHelp( "Switches /V and /Q are mutually exclusive" );
						}
						verbose = true;
						break;
					case "/V":
						if ( verbose )
						{
							return ShowHelp( "Duplicate command line switch /V" );
						}
						if ( quiet )
						{
							return ShowHelp( "Switches /V and /Q are mutually exclusive" );
						}
						verbose = true;
						break;
					case "/W":
						if ( drive != null )
						{
							if ( drive == windrive )
							{
								return ShowHelp( "Either specify a drive letter or use the /W switch, not both" );
							}
							else
							{
								return ShowHelp( "Duplicate drive specification {0} and {1}", drive, arg.ToUpper( ) );
							}
						}
						drive = windrive;
						break;
					default:
						bool validdrive = false;
						DriveInfo[] alldrives = DriveInfo.GetDrives( );
						foreach ( DriveInfo drvinf in alldrives )
						{
							if ( drvinf.Name == arg.ToUpper( ) + "\\" )
							{
								validdrive = true;
								drive = arg.ToUpper( );
							}
						}
						if ( !validdrive )
						{
							return ShowHelp( "Invalid command line argument \"{0}\"", arg );
						}
						break;
				}
			}

			verbose = verbose || listonly;

			if ( !confirm )
			{
				flags |= RecycleFlags.RecycleNoConfirmation;
			}
			if ( !progress )
			{
				flags |= RecycleFlags.RecycleNoProgressUI;
			}

			#endregion Parse Command Line


			#region Verbose Output

			if ( verbose )
			{
				foreach ( DriveInfo diskdrive in DriveInfo.GetDrives( ) )
				{
					if ( diskdrive.DriveType == DriveType.Fixed ) // local harddisks only
					{
						string recyclebin = Path.Combine( diskdrive.Name, "$RECYCLE.BIN" );
						if ( Directory.Exists( recyclebin ) )
						{
							long size = 0;
							int items = 0;
							string[] files = new string[0];
							string[] folders = Directory.GetDirectories( recyclebin );
							foreach ( string folder in folders )
							{
								try
								{
									// assuming any access denied will occur on the first directory level
									files = Directory.GetFiles( folder, "*.*", SearchOption.AllDirectories );
									foreach ( string file in files )
									{
										size += new FileInfo( file ).Length;
										items++;
									}
								}
								catch ( UnauthorizedAccessException )
								{
									accessdenied = true;
									accessdenieddirs++;
								}
							}
							if ( items == 1 )
							{
								Console.WriteLine( "Marking 1 file ({1}) from drive {2} for deletion", items, FormatBytes( size ), diskdrive.Name.Remove( 2 ) );
								totalsize += size;
								deleteditems += items;
							}
							else if ( items > 1 )
							{
								Console.WriteLine( "Marking {0} files ({1}) from drive {2} for deletion", items, FormatBytes( size ), diskdrive.Name.Remove( 2 ) );
								totalsize += size;
								deleteditems += items;
							}
						}
					}
				}
			}

			#endregion Verbose Output


			#region Actual Deletion

			if ( listonly )
			{
				Console.WriteLine( "\n{0} items with a total size of {1} would have been deleted.", deleteditems, FormatBytes( totalsize ) );
			}
			else
			{
				uint result = SHEmptyRecycleBin( IntPtr.Zero, drive, flags );
				if ( result == 0 )
				{
					if ( !quiet )
					{
						Console.WriteLine( "\n{0} items with a total size of {1} have been permanently deleted.", deleteditems, FormatBytes( totalsize ) );
						if ( accessdenied )
						{
							if ( accessdenieddirs == 1 )
							{
								Console.WriteLine( "Not all items could be removed permanently because access was denied to 1 directory." );
							}
							else
							{
								Console.WriteLine( "Not all items could be removed permanently because access was denied to {0} directories.", accessdenieddirs );
							}
						}
					}
					rc = 0;
				}
				else
				{
					if ( !quiet )
					{
						Console.WriteLine( "\nNot all items could be removed permanently." );
					}
					rc = 1;
				}
			}

			#endregion Actual Deletion


			return rc;
		}


		static string FormatBytes( long bytes )
		{
			int KB = 1024;
			int MB = 1024 * KB;
			int GB = 1024 * MB;
			if ( bytes < KB )
			{
				return bytes.ToString( ) + " B";
			}
			else if ( bytes < MB )
			{
				return ( bytes / KB ).ToString( ) + " KB";
			}
			else if ( bytes < GB )
			{
				return ( bytes / MB ).ToString( ) + " MB";
			}
			else
			{
				return ( bytes / GB ).ToString( ) + " GB";
			}
		}


		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

			/*
			DelTrash.exe,  Version 1.03
			Empty the Recycle Bin
			
			Usage:   DelTrash.exe  [ drive: | /W ]  [ /C ]  [ /P ]  [ /L | /Q | /V ]
			
			Where:   drive:  empty recycle bin on this drive only (default: all drives)
			         /W      empty recycle bin on Windows' drive only (default: all drives)
			         /C      prompt for Confirmation
			         /L      List only, do not delete
			         /P      show Progress bar
			         /Q      Quiet mode, no screen output
			         /V      Verbose mode, show number of files and total size per disk drive
			
			Notes:   Switches /L and /Q and /V are mutually exclusive.
			         Return code is 0 if the Recycle Bin was emptied successfully, or 1
			         if there was nothing to delete or in case of (command line) errors.
			
			Credits: Based on code by Vinoth Kumar
			         www.codeproject.com/Articles/20172/Empty-the-Recycle-Bin-using-C
			         Number of items and size calculation based on 

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

			#endregion Help Text


			#region Display Help Text

			Console.Error.WriteLine( );

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

			Console.Error.WriteLine( "Empty the Recycle Bin" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:   " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "DelTrash.exe  [ drive: | /W ]  [ /C ]  [ /P ]  [ /L | /Q | /V ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:   " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "drive:" );
			Console.ResetColor( );
			Console.Error.WriteLine( "  empty recycle bin on this drive only (default: all drives)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /W" );
			Console.ResetColor( );
			Console.Error.Write( "      empty recycle bin on " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "W" );
			Console.ResetColor( );
			Console.Error.WriteLine( "indows' drive only (default: all drives)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /C" );
			Console.ResetColor( );
			Console.Error.Write( "      prompt for " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "C" );
			Console.ResetColor( );
			Console.Error.WriteLine( "onfirmation" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /L      L" );
			Console.ResetColor( );
			Console.Error.WriteLine( "ist only, do not delete" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "         /P" );
			Console.ResetColor( );
			Console.Error.Write( "      show " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "P" );
			Console.ResetColor( );
			Console.Error.WriteLine( "rogress bar" );

			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( "         /V      V" );
			Console.ResetColor( );
			Console.Error.WriteLine( "erbose mode, show number of files and total size per disk drive" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Notes:   Switches " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/L" );
			Console.ResetColor( );
			Console.Error.Write( " and " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/Q" );
			Console.ResetColor( );
			Console.Error.Write( " and " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/V" );
			Console.ResetColor( );
			Console.Error.WriteLine( " are mutually exclusive." );

			Console.Error.WriteLine( "         Return code is 0 if the Recycle Bin was emptied successfully, or 1" );

			Console.Error.WriteLine( "         if there was nothing to delete or in case of (command line) errors." );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Credits: Based on code by Vinoth Kumar" );

			Console.ForegroundColor = ConsoleColor.DarkGray;
			Console.Error.WriteLine( "         www.codeproject.com/Articles/20172/Empty-the-Recycle-Bin-using-C" );
			Console.ResetColor( );

			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;
		}


		public enum RecycleFlags : uint
		{
			RecycleNoConfirmation = 0x00000001,
			RecycleNoProgressUI = 0x00000002,
			RecycleNoSound = 0x00000004
		}


		[DllImport( "Shell32.dll", CharSet = CharSet.Unicode )]
		static extern uint SHEmptyRecycleBin( IntPtr hwnd, string pszRootPath, RecycleFlags dwFlags );
	}
}