import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.Array;

import javax.imageio.ImageIO;


public class patronus {
	
	public static void gen(String origen, String destino) throws IOException
	{
		// Variables para el tratamiento de los ficheros de entrada / salida
		File inFile, outFile;
		FileInputStream inReader;
		FileWriter outWriter;
		
		// Cargamos el fichero	
		inFile = new File(origen);
		outFile = new File(destino);
		
		if (!inFile.exists())
		{
			System.out.println("Input file doesn't exist");
			System.exit(-1);
		}
		
	    inReader = new FileInputStream(inFile);
	    
	    // Calculamos tamaño del fichero y de la imagen resultante
	    double fileSize = inFile.length();
	    String fileSizeStr = String.valueOf((long)fileSize);
	    int imgSize = (int) (Math.sqrt(fileSize + fileSizeStr.length() + 1));
	    int rest = (int) (fileSize - imgSize*imgSize); 
	    int width = imgSize;
	    if (rest > 0)
	    	width += rest / imgSize;
	    
	    while ((imgSize * width) < (fileSize + fileSizeStr.length() + 1)) width++;
	    		    
	    BufferedImage bufferedImage = new BufferedImage(width, imgSize, BufferedImage.TYPE_INT_RGB);
	    
	    // Comenzamos la lectura del fichero y la creación de la imagen
	    int c;
	    int x,y;
	    
	    x = y = 0;
	    
	    // Primero codificamos el tamaño real del fichero, para su posterior recuperación    
	    for (int i = 0; i<fileSizeStr.length(); i++)
	    {
	    	bufferedImage.setRGB(x,y, fileSizeStr.charAt(i));
	    	x++;
	    	if (x >= width) 
    		{
    			x = 0;
    			y++;
    		}
	    }
	    
	    // Insertamos caracter finalizador
    	bufferedImage.setRGB(x,y, 255);
    	x++;
    	if (x >= width) 
		{
			x = 0;
			y++;
		}
	    
	    while ((c = inReader.read())!= -1)
	    {	    	    
	    		bufferedImage.setRGB(x,y,c);
	    		x++;
	    		if (x >= width) 
	    		{
	    			x = 0;
	    			y++;
	    		}
	    }

		ImageIO.write(bufferedImage, "png", outFile);
	    inReader.close();
	}
	
	public static void rev(String origen, String destino) throws IOException
	{
		// Variables para el tratamiento de los ficheros de entrada / salida
		File inFile, outFile;
		FileReader inReader;
		FileOutputStream outWriter; 
		 
		// Cargamos el fichero
		inFile = new File(origen);
		outFile = new File(destino);
		
		if (!inFile.exists())
		{
			System.out.println("Input file doesn't exist");
			System.exit(-1);
		}
		
	    outWriter = new FileOutputStream(outFile);
	    
	    BufferedImage bufferedImage  = ImageIO.read(inFile);

	    // Comenzamos la lectura de la imagen y la recreación del fichero original
	    int c;
	    int x,y, maxX, maxY;
	    
	    x = y = 0;
	    maxX = bufferedImage.getWidth();
	    maxY = bufferedImage.getHeight();
	    
	    long size = 0, count = 1;
	    StringBuffer sizeStr = new StringBuffer(); 
	    
	    for (y=0; y<maxY; y++)
	    {
	    	for (x=0; x<maxX; x++)
	    	{   
	    		c = bufferedImage.getRGB(x,y);
	    		
	    		if (size == 0)
	    		{
	    			// Obtenemos tamaño del fichero destino
	    			if ((char) c == 255)
	    			{
	    				size = Long.parseLong(sizeStr.toString());
	    			}
	    			else 
	    			{
	    				sizeStr.append((char)c);
	    			}
	    				
	    		}
	    		else 
	    		{
	    		   outWriter.write(c);
	    		   outWriter.flush();
	    		   count++;
	    		   if (count > size) break; 
	    		}
	    	}
	    	if (count > size) break;  
	    }
	    outWriter.close();
	}	
	
	public static void usage()
	{
		System.out.println("Usage: patronus <gen|rev> <source> <dest>");
		
		System.out.println("\ngen: generate a PNG file from the source file");
		System.out.println("rev: from a PNG file previosly generated, recover the original file");
		
		System.out.println("\nThis software is distributed under GPL Licence");
		System.out.println("This software is distributed without any guarantees");
		System.out.println("Written by Víctor Henríquez (www.sendaoscura.com)");
		System.exit(-1);
	}
	
	/**
	 * Basado en la idea de Ruben Santamarta (Blog 48bits)
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		if (args.length != 3) usage();
		
		if ("gen".equalsIgnoreCase(args[0])) gen(args[1], args[2]);
		else if ("rev".equalsIgnoreCase(args[0])) rev(args[1], args[2]);
		else usage();
	}

}