using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;


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


		static int Main( string[] args )
		{
			if ( args.Length != 2 )
			{
				return ShowHelp( );
			}
			if ( !File.Exists( args[0] ) )
			{
				return ShowHelp( "File \"{0}\" not found", args[0] );
			}
			if ( !File.Exists( args[1] ) )
			{
				return ShowHelp( "File \"{0}\" not found", args[1] );
			}

			Bitmap bmp1, bmp2;
			try
			{
				bmp1 = new Bitmap( args[0] );
				bmp2 = new Bitmap( args[1] );
			}
			catch ( Exception e )
			{
				return ShowHelp( e.Message );
			}

			if ( bmp1.Width != bmp2.Width || bmp1.Height != bmp2.Height )
			{
				return ShowHelp( "Images have different dimensions" );
			}

			for ( int i = 0; i < bmp1.Width; i++ )
			{
				for ( int j = 0; j < bmp1.Height; j++ )
				{
					Color pixel1 = bmp1.GetPixel( i, j );
					Color pixel2 = bmp2.GetPixel( i, j );
					if ( pixel1.A != pixel2.A || pixel1.R != pixel2.R || pixel1.G != pixel2.G || pixel1.B != pixel2.B )
					{
						Console.ForegroundColor = ConsoleColor.Red;
						Console.WriteLine( "Images are NOT identical" );
						Console.ResetColor( );
						return 1;
					}
				}
			}

			Console.ForegroundColor = ConsoleColor.Green;
			Console.WriteLine( "Images are identical" );
			Console.ResetColor( );
			return 0;
		}


		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

			/*
			CompareImages.exe,  Version 1.00
			Compare 2 images pixel by pixel, ignoring EXIF and IPTC metadata

			Usage:    COMPAREIMAGES.EXE  image1  image2

			Where:    image1, image2     are the images to be compared

			Note:     Return code (\"ErrorLevel\") 0 if images are identical,
			          1 if they are not, or -1 in case of command line or file
			          IO errors or if files not recognized as images.

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

			#endregion Help Text


			#region Display Help Text

			Console.Error.WriteLine( );

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

			Console.Error.WriteLine( "Compare 2 images pixel by pixel, ignoring EXIF and IPTC metadata" );

			Console.Error.WriteLine( );

			Console.Error.Write( "Usage:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.WriteLine( "COMPAREIMAGES.EXE  image1  image2" );
			Console.ResetColor( );

			Console.Error.WriteLine( );

			Console.Error.Write( "Where:    " );
			Console.ForegroundColor = ConsoleColor.White;
			Console.Error.Write( "image1, image2" );
			Console.ResetColor( );
			Console.Error.WriteLine( "     are the images to be compared" );

			Console.Error.WriteLine( );

			Console.Error.WriteLine( "Note:     Return code (\"ErrorLevel\") 0 if images are identical," );

			Console.Error.WriteLine( "          1 if they are not, or -1 in case of command line or file" );

			Console.Error.WriteLine( "          IO errors or if files not recognized as images." );

			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;
		}
	}
}