import java.awt.Color;
import java.awt.image.BufferedImage;

@SuppressWarnings("unused")
public class Sharpen implements BaseFilter {

    float[][] matrix =
        {
            {0f,    -0.67f, 0f},
            {-0.67f, 3.67f, -0.67f},
            {0f,  -0.67f, 0f}
        };

    /*
     * (2, 1): (0, 0) = (1, 0)
     * (2, 1): (1, 0) = (2, 0)
     * (2, 1): (2, 0) = (3, 0)
     * (2, 1): (0, 0) = (1, 0)
     * */

    @Override
    public BufferedImage process(BufferedImage source) {
        // TODO : implementacija

        int width = source.getWidth();
        int height = source.getHeight();

        BufferedImage result = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        for (int i = 0; i < width; i++) {
            result.setRGB(i, 0, source.getRGB(i, 0));
            result.setRGB(i, height - 1, source.getRGB(i, height - 1));
        }

        for (int j = 0; j < height; j++) {
            result.setRGB(0, j, source.getRGB(0, j));
            result.setRGB(width-1, j, source.getRGB(width-1, j));
        }

        for (int x = 1; x < width - 1; x++)
            for (int y = 1; y < height - 1; y++) {
                int redValue = 0;
                int blueValue = 0;
                int greenValue = 0;

                for (int xm = 0; xm < 3; xm++)
                    for (int ym = 0; ym < 3; ym++) {
                        int newX = x + xm - 1;
                        int newY = y + ym -1;

                        Color color = new Color(source.getRGB(newX, newY));
                        float factor = matrix[xm][ym];

                        int red = (int)(color.getRed() * factor);
                        int green = (int)(color.getGreen() * factor);
                        int blue = (int)(color.getBlue() * factor);

                        redValue +=  red;
                        blueValue += blue;
                        greenValue += green;
                    }

                redValue = Math.min(255, Math.max(0, redValue));
                blueValue = Math.min(255, Math.max(0, blueValue));
                greenValue = Math.min(255, Math.max(0, greenValue));

                int newRGB = new Color(redValue, greenValue, blueValue).getRGB();
                result.setRGB(x, y, newRGB);
            }

        return result;
    }
}