using System;
using System.Collections.Generic;
using System.Threading;


namespace RobvanderWoude
{
	internal class ProgressBar
	{
		static readonly string progver = "2.00";


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

			int currentvalue = 0;
			bool currentset = false;
			int minimumvalue = 0;
			bool minimumset = false;			
			int maximumvalue = 100;
			bool maximumset = false;
			int parsedargs = 0;
			ConsoleColor poscolor = ConsoleColor.Green;
			bool poscolorset = false;
			ConsoleColor negcolor = ConsoleColor.Green;
			bool negcolorset = false;
			bool linearscale = false;
			bool writescale = true;
			bool debug = false;
#if DEBUG
			debug = true;
#endif
			#endregion Initialize Variables


			#region Parse Command Line

			if ( args.Length == 0 )
			{
				return ShowHelp( );
			}

			foreach ( string arg in args )
			{
				if ( arg == "/?" )
				{
					return ShowHelp( );
				}
				if ( arg.ToUpper( ) == "/C" )
				{
					// /C should be the only argument
					if ( args.Length != 1 )
					{
						return ShowHelp( );
					}
					// Display valid colors
					Console.WriteLine( "Valid colors:" );
					Console.WriteLine( "=============" );
					foreach ( ConsoleColor color in Enum.GetValues( typeof( ConsoleColor ) ) )
					{
						Console.ForegroundColor = color;
						// Prevent "invisible" text when foreground color equals background color
						if ( Math.Abs( Console.ForegroundColor - Console.BackgroundColor ) < 2 )
						{
							Console.BackgroundColor = (ConsoleColor)( ( (int)color + 7 ) % 16 );
						}
						Console.Write( "{0,-13}", Enum.GetName( typeof( ConsoleColor ), color ) );
						Console.ResetColor( );
						Console.WriteLine( );
					}
					return 0;
				}
				else if ( arg.ToUpper( ) == "/D" )
				{
					debug = true;
					parsedargs++;
				}
				else if ( arg.ToUpper( ) == "/L" )
				{
					linearscale = true;
					parsedargs++;
				}
				else if ( arg.ToUpper( ) == "/NS" )
				{
					writescale = false;
					parsedargs++;
				}
				else if ( int.TryParse( arg, out int test ) )
				{
					if ( !currentset ) // First numeric value is the mandatory current value
					{
						currentvalue = test;
						currentset = true;
					}
					else if ( !minimumset ) // Second numeric value can be either the minimum or maximum value
					{
						minimumvalue = test;
						minimumset = true;
					}
					else if ( !maximumset ) // Third numeric value must be the maximum value
					{
						maximumvalue = test;
						maximumset = true;
					}
					else // No more numeric values allowed
					{
						return ShowHelp( "Invalid command line argument \"{0}\"", arg );
					}
					parsedargs++;
				}
				else
				{
					bool validcolor = false;
					foreach ( ConsoleColor color in Enum.GetValues( typeof( ConsoleColor ) ) )
					{
						if ( arg.ToUpper( ) == Enum.GetName( typeof( ConsoleColor ), color ).ToUpper( ) )
						{
							if ( !poscolorset )
							{
								poscolor = color;
								poscolorset = true;
								validcolor = true;
								parsedargs++;
							}
							else if ( !negcolorset )
							{
								negcolor = color;
								negcolorset = true;
								validcolor = true;
								parsedargs++;
							}
							else
							{
								validcolor = false;
							}
						}
					}
					if ( !validcolor )
					{
						return ShowHelp( "Invalid color \"{0}\", use /C switch to show valid colors", arg );
					}
				}
			}

			#endregion Parse Command Line


			#region Validate Command Line

			if ( !maximumset )
			{
				if ( !minimumset )
				{
					maximumvalue = 100;
					maximumset = false;
					minimumvalue = 0;
					minimumset = false;
				}
				else
				{
					maximumvalue = minimumvalue;
					maximumset = true;
					minimumvalue = 0;
					minimumset = false;
				}
			}

			if ( minimumvalue * maximumvalue >= 0 )
			{
				if ( negcolorset )
				{
					return ShowHelp( "Specify a second color only if minimum < 0 and maximum > 0" );
				}
				linearscale = true;
			}

			if ( currentvalue == maximumvalue + 1 )
			{
				currentvalue = maximumvalue;
			}
			else if ( currentvalue < minimumvalue || currentvalue > maximumvalue + 1 )
			{
				return ShowHelp( "Invalid current value \"{0}\"", currentvalue.ToString( ) );
			}

			if ( parsedargs != args.Length )
			{
				return ShowHelp( "Invalid command line, most likely caused by duplicate arguments" );
			}

			#endregion Validate Command Line


			Console.ResetColor( );


			#region Scale

			if ( writescale )
			{
				string scale;
				if ( minimumvalue < 0 && maximumvalue > 0 )
				{
					int zeropos = (int)Math.Floor( Console.WindowWidth * (double)-minimumvalue / ( maximumvalue - minimumvalue ) );
					scale = string.Format( "{0}{1}0{2}{3}", minimumvalue, new string( ' ', zeropos - minimumvalue.ToString( ).Length ), new string( ' ', Console.WindowWidth - zeropos - minimumvalue.ToString( ).Length ), maximumvalue );
				}
				else
				{
					scale = string.Format( "{0}{1}{2}", minimumvalue, new string( ' ', Console.WindowWidth - minimumvalue.ToString( ).Length - maximumvalue.ToString( ).Length  ), maximumvalue );
				}
				Console.ForegroundColor = poscolor;
				Console.WriteLine( scale );
				Console.ResetColor( );
				if ( debug )
				{
					Thread.Sleep( 1000 );
				}
			}

			#endregion Scale


			// Move down 1 line and then return to the one above current one, to make sure we're not at the bottom line of the screen
			Console.WriteLine( );
			int linenumber = Console.CursorTop - 1;
			Console.SetCursorPosition( 0, linenumber );

			// Calculate progress bar length
			double progress = Math.Min( 1F, ( currentvalue - (double)minimumvalue ) / ( maximumvalue - (double)minimumvalue ) );
			int progressbarlength = (int)( progress * Console.WindowWidth );

			// Display the calculated progress bar
			if ( negcolorset )
			{
				if ( linearscale )
				{
					int negbarlength = (int)( -minimumvalue * Console.WindowWidth / ( maximumvalue - minimumvalue ) );
					Console.BackgroundColor = negcolor;
					Console.Write( new string( ' ', Math.Min( progressbarlength, negbarlength ) ) );
					if ( progressbarlength > negbarlength )
					{
						Console.BackgroundColor = poscolor;
						Console.Write( new string( ' ', progressbarlength - negbarlength ) );
					}
					// Erase remainder of line
					Console.ResetColor( );
					Console.Write( new string( ' ', Console.WindowWidth - progressbarlength ) );
				}
				else
				{
					if ( currentvalue == 0 )
					{
						Console.ResetColor( );
						Console.Write( new string( ' ', Console.WindowWidth ) );
					}
					else
					{
						int neghalflength = (int)( -minimumvalue * Console.WindowWidth / ( maximumvalue - minimumvalue ) );
						int poshalflength = Console.WindowWidth - neghalflength;
						if ( currentvalue < 0 )
						{
							progress = (double)currentvalue / minimumvalue;
							progressbarlength = (int)( progress * neghalflength );
							Console.ResetColor( );
							Console.Write( new string( ' ', neghalflength - progressbarlength ) );
							Console.BackgroundColor = negcolor;
							Console.Write( new string( ' ', progressbarlength ) );
							// Erase remainder of line
							Console.ResetColor( );
							Console.Write( new string( ' ', poshalflength ) );
						}
						else
						{
							progress = (double)currentvalue / maximumvalue;
							progressbarlength = (int)( progress * poshalflength );
							Console.ResetColor( );
							Console.Write( new string ( ' ', neghalflength ) );
							Console.BackgroundColor = poscolor;
							Console.Write( new String( ' ', progressbarlength ) );
							Console.ResetColor( );
							// Erase remainder of line
							Console.ResetColor( );
							Console.Write( new string( ' ', poshalflength - progressbarlength ) );

						}
					}
				}
			}
			else
			{
				Console.BackgroundColor = poscolor;
				string progressbar = new string( ' ', progressbarlength );
				Console.Write( progressbar );
				// Erase remainder of line
				Console.ResetColor( );
				Console.Write( new string( ' ', Console.WindowWidth - progressbarlength ) );
			}

			// Move the cursor back to the start of the line
			Console.SetCursorPosition( 0, linenumber );

			return 0;
		}


		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

			/*
			ProgressBar.exe,  Version 2.00
			Batch tool to display a progress bar
 
			Usage:    ProgressBar   current  [ options ]

			or:       ProgressBar   /C
 
			Where:    current       is the current value

			Options:  minimum       is the minimum value      (default:     0)
			          maximum       is the maximum value      (default:   100)
			          color         is the progress bar color (default: Green)
			          2ndcolor      is the "sub zero" color   (default: Green)
			          /C            list valid Colors (no other arguments allowed)
			          /L            start progress bar at Left (default: start at 0)
			          /NS           do Not show Scale above progress bar
 
			Notes:    /L means the progress bar starts at the minimum value, whereas
			          by default the progress bar starts at 0. If the range
			          minimum..maximum does not include 0, /L is assumed.
			          Return code -1 in case of (command line) errors, otherwise 0.
 
			Written by Rob van der Woude
			https://www.robvanderwoude.com
			*/

			#endregion Help Text


			#region Display Help Text

			Console.Error.WriteLine( );

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

			Console.Error.WriteLine( "Batch tool to display a progress bar" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "ProgressBar   current  [ options ]" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "or:       " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "ProgressBar   /C" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "current" );
			Console.ResetColor( );
			Console.Error.WriteLine( "       is the current value" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Options:  " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "minimum" );
			Console.ResetColor( );
			Console.Error.WriteLine( "       is the minimum value      (default:     0)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          maximum" );
			Console.ResetColor( );
			Console.Error.WriteLine( "       is the maximum value      (default:   100)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          color" );
			Console.ResetColor( );
			Console.Error.WriteLine( "         is the progress bar color (default: Green)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          2ndcolor" );
			Console.ResetColor( );
			Console.Error.WriteLine( "      is the \"sub zero\" color   (default: Green)" );


			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /C" );
			Console.ResetColor( );
			Console.Error.WriteLine( "            list valid Colors (no other arguments allowed)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /L" );
			Console.ResetColor( );
			Console.Error.WriteLine( "            start progress bar at Left (default: start at 0)" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          /NS" );
			Console.ResetColor( );
			Console.Error.WriteLine( "           do Not show Scale above progress bar" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Notes:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/L" );
			Console.ResetColor( );
			Console.Error.Write( " means the progress bar starts at the " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "minimum" );
			Console.ResetColor( );
			Console.Error.WriteLine( " value, whereas" );

			Console.Error.WriteLine( "          by default the progress bar starts at 0. If the range" );

			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "          minimum..maximum" );
			Console.ResetColor( );
			Console.Error.Write( " does not include 0, " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "/L" );
			Console.ResetColor( );
			Console.Error.WriteLine( " is assumed." );

			Console.Error.WriteLine( "          Return code -1 in case of (command line) 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 Text


			return -1;
		}
	}
}