import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;
import java.io.IOException;
import java.lang.Math;

class ParseOptions {
	String input = "";
	String output = "";
	int radius = 30;
	public void parse(String[] args) {
		input = args[args.length-1];
		output = "enhanced_" + input;
		for (int i = 0; i < (args.length - 1); i++) {
			//System.out.println(args[i]);
			if (args[i].equals("-o") || args[i].equals("--output")) {
				output = args[i+1];
				++i;
			}
			if (args[i].equals("-r") || args[i].equals("--radius")) {
				radius = Integer.parseInt(args[i+1]);
				++i;
			}
			if (args[i].equals("-d") || args[i].equals("--dpi")) {
				radius = (Integer.parseInt(args[i+1])) / 10;
				++i;
			}
		}
	}
}

class EnhanceBookPhoto {
	static double distance(float x1, float y1, float x2, float y2) {
		return(Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)));
	}
	static double interpolate(int x1, double y1, int x2, double y2, double x) {
		if (x1 == x2) {
			return(y1);
		}
		double yStepPerUnitOfX = (y2 - y1) / ((double)x2 - (double)x1);
		double y = y1 + (yStepPerUnitOfX * (double)(x - x1));
		return y;
	}
	static int interpolate2d(double x, double y, int[][] blurArray) {
		x = ((int)x >= blurArray.length) ? (blurArray.length - 1) : x;
		y = ((int)y >= blurArray[0].length) ? (blurArray[0].length - 1) : y;
		if ((x == Math.round(x)) && (y == Math.round(y))) {
			return(blurArray[(int)x][(int)y]);
		}
		int prevX = (int)x;
		int prevY = (int)y;
		int nextX = ((int)x + 1) >= blurArray.length ? (int)x : (int)x + 1;
		int nextY = ((int)y + 1) >= blurArray[0].length ? (int)y : (int)y + 1;
		int NW = blurArray[prevX][prevY];
		int NE = blurArray[nextX][prevY];
		int SW = blurArray[prevX][nextY];
		int SE = blurArray[nextX][nextY];
		double valueInUpperRow = interpolate(prevX, NW, nextX, NE, x);
		double valueInLowerRow = interpolate(prevX, SW, nextX, SE, x);
		double result = interpolate(prevY, valueInUpperRow, nextY, valueInLowerRow, y);
		return((int)result);
	}
	static int[] pixel2rgb(int pixel) {
		int[] result = {
			(pixel & 0x00FF0000) >> 16,
			(pixel & 0x0000FF00) >> 8,
			(pixel & 0x000000FF)
		};
		return(result);
	}
	static int pixelValue(int pixel) {
		int[] samples = {
			(pixel & 0x00FF0000) >> 16,
			(pixel & 0x0000FF00) >> 8,
			(pixel & 0x000000FF)
		};
		return ((samples[0] + samples[1] + samples[2]) / 3);
	}
	static int pixel2int(int[] pixel) {
		return(
			(pixel[0] << 16) +
			(pixel[1] << 8) +
			pixel[2]
		);
	}
	static void enhanceBookPhoto(String input, String output, int radius) {
		BufferedImage originalImage = null;
		try {
			originalImage = ImageIO.read(new File(input));
		} catch (IOException e) {
			e.printStackTrace();
		}
		int originalHeight = originalImage.getHeight(null);
		int originalWidth = originalImage.getWidth(null);
		int bluredHeight = (int)(originalHeight / radius);
		int bluredWidth = (int)(originalWidth / radius);
		int[][] blured = new int[bluredWidth][bluredHeight];
		for (int y = 0; y < bluredHeight; y++) {
			for (int x = 0; x < bluredWidth; x++) {
				int sum = 0;
				for (int bluredX = x * radius; bluredX < (x + 1) * radius; bluredX++) {
					for (int bluredY = y * radius; bluredY < (y + 1) * radius; bluredY++) {
						sum += pixelValue(originalImage.getRGB(bluredX, bluredY));
					}
				}
				blured[x][y] = sum / (radius*radius);
			}
		}
		for (int y = 0; y < originalHeight; y++) {
			for (int x = 0; x < originalWidth; x++) {
				int[] pixel = pixel2rgb(originalImage.getRGB(x, y));
				for (int channel = 0; channel < 3; channel++) {
					float bluredX = x/(float)radius;
					float bluredY = y/(float)radius;
					float bluredSample = interpolate2d(bluredX, bluredY, blured) / 255f;
					float actualSample = pixel[channel] / 255f;
					float result = (bluredSample > 0) ? (actualSample / bluredSample) : 1;
					result = (result > 1) ? 1 : result;
					pixel[channel] = (int)(result * 255);
					//pixel[channel] = (int)(bluredSample*255);
				}
				originalImage.setRGB(x, y, pixel2int(pixel));
			}
		}
		try {
			String format = output.substring(output.lastIndexOf('.') + 1);
			ImageIO.write(originalImage, format, new File(output));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	public static void main(String[] args) {
		if (args.length == 0) {
			System.out.println("Usage: java -jar enhance_book_photo.jar picture.png\nYou can use some options, too - read docs for details.");
			System.exit(0);
		}
		ParseOptions parser = new ParseOptions();
		parser.parse(args);
		enhanceBookPhoto(parser.input, parser.output, parser.radius);
	}
}