package class8_2_BlurringWithBufferedImage;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * This {@link Filterer} blurs the image by mixing the color of each pixel
 * with the colors of the pixels around it.
 */
public class ImageBlurrer implements Filterer {
    private BufferedImage image;
    private Random generator = new Random();

    public ImageBlurrer() {
        image = new BufferedImage(512,512,BufferedImage.TYPE_3BYTE_BGR);
        for(int row = 0; row < image.getHeight(); row++) {
            for(int col = 0; col < image.getHeight(); col++) {
                int rgb = 0xFF000000 | generator.nextInt();
                image.setRGB(col, row, rgb);
            }
        }
    }

    @Override
    public Image getImage() {
        return image;
    }

    @Override
    public void doFilterStep() {
        final int NUM_NEIGHBORS = 8;
        // Offsets:
        final int[] colOff = {0,1,1,1,0,-1,-1,-1};
        final int[] rowOff = {-1,-1,0,1,1,1,0,-1};
        assert(colOff.length == NUM_NEIGHBORS);
        assert(rowOff.length == NUM_NEIGHBORS);
        final int[] neighRgb = new int[NUM_NEIGHBORS];

        for(int row = 0; row < image.getHeight(); row++) {
            for(int col = 0; col < image.getHeight(); col++) {
                int numNonBorderNeighs = 0;
                for(int indNeigh = 0; indNeigh < NUM_NEIGHBORS; indNeigh++) {
                    int neighRow = row+rowOff[indNeigh];
                    int neighCol = col+colOff[indNeigh];
                    if(neighRow>=0 && neighRow<image.getHeight()
                            && neighCol>=0 && neighCol<image.getWidth()) {
                        neighRgb[numNonBorderNeighs++] = image.getRGB(neighCol,neighRow);
                    }
                }
                int r = 0;
                int g = 0;
                int b = 0;
                for(int indNeigh=0; indNeigh<numNonBorderNeighs; indNeigh++) {
                    int rgb = neighRgb[indNeigh];
                    r += (0x00ff0000 & rgb) >> 16;
                    g += (0x0000ff00 & rgb) >> 8;
                    b += (0x000000ff & rgb);
                }
                r/=numNonBorderNeighs; // TODO: Rounding?
                g/=numNonBorderNeighs;
                b/=numNonBorderNeighs;
                int rgb = 0xff000000 | (r << 16) | (g << 8) | b;
                image.setRGB(col, row, rgb);
            }
        }
    }
}