package line;

import java.awt.Point;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.imageio.ImageIO;

import snake.Image;

public class Lines {

    private final static int NB_LINES = 5000;
    private final static int MIN_LENGTH = 10;
    private final static int MAX_LENGTH = 50;

    public static void main(String[] args) throws IOException {
        BufferedImage src = ImageIO.read(Image.class.getClassLoader().getResourceAsStream("joconde.png"));
        BufferedImage dest = new BufferedImage(src.getWidth(), src.getHeight(), BufferedImage.TYPE_INT_RGB);


        int [] bgColor = {0, 0, 0};
        int avgRed = 0, avgGreen = 0, avgBlue = 0, count = 0;
        for (int y = 0; y < src.getHeight(); y++) {
            for (int x = 0; x < src.getWidth(); x++) {
                int colsrc = src.getRGB(x, y);
                avgRed += colsrc & 255;
                avgGreen += (colsrc >> 8) & 255;
                avgBlue += (colsrc >> 16) & 255;
                count++;
            }
        }

        bgColor[0] = avgBlue/count; bgColor[1] = avgGreen/count; bgColor[2] = avgRed/count;
        for (int y = 0; y < src.getHeight(); y++) {
            for (int x = 0; x < src.getWidth(); x++) {
                dest.getRaster().setPixel(x, y, bgColor);
            }
        }
        List<List<Point>> lines = new ArrayList<List<Point>>();
        Random rand = new Random();
        for (int i = 0; i < NB_LINES; i++) {
            int length = rand.nextInt(MAX_LENGTH - MIN_LENGTH) + MIN_LENGTH;
            double ang = rand.nextDouble() * Math.PI;
            int lx = (int)(Math.cos(ang) * length); // can be negative or positive
            int ly = (int)(Math.sin(ang) * length); // positive only
            int sx = rand.nextInt(dest.getWidth() -1 - Math.abs(lx));
            int sy = rand.nextInt(dest.getHeight() - 1- Math.abs(ly));
            List<Point> line;
            if (lx > 0) {
                line = line(sx, sy, sx+lx, sy+ly);
            } else {
                line = line(sx+Math.abs(lx), sy, sx, sy+ly);
            }
            lines.add(line);
        }

        // render the picture
        int [] color = {0, 0, 0};
        for (List<Point> line : lines) {

            avgRed = 0; avgGreen = 0; avgBlue = 0;
            count = 0;
            for (Point p : line) {
                int colsrc = src.getRGB(p.x, p.y);
                avgRed += colsrc & 255;
                avgGreen += (colsrc >> 8) & 255;
                avgBlue += (colsrc >> 16) & 255;
                count++;
            }
            avgRed /= count; avgGreen /= count; avgBlue /= count;
            color[0] = avgBlue; color[1] = avgGreen; color[2] = avgRed;
            for (Point p : line) {
                dest.getRaster().setPixel(p.x, p.y, color);
            }

        }
        ImageIO.write(dest, "png", new File("a0.png"));

    }

    private static List<Point> line(int x0, int y0, int x1, int y1) {
        List<Point> points = new ArrayList<Point>();
        int deltax = x1 - x0;
        int deltay = y1 - y0;
        int tmp;
        double error = 0;
        double deltaerr = 0;
        if (Math.abs(deltax) >= Math.abs(deltay)) {
            if (x0 > x1) { // swap the 2 points
                tmp = x0; x0 = x1; x1 = tmp;
                tmp = y0; y0 = y1; y1 = tmp;
                deltax = - deltax; deltay = -deltay;
            }
            deltaerr = Math.abs (((double)deltay) / deltax);
            int y = y0;
            for (int x = x0; x <= x1; x++) {
                points.add(new Point(x, y));
                error += deltaerr;
                if (error >= 0.5) {
                    if (y0 < y1) y++; else y--;
                    error -= 1.0;
                }
            }
        } else {
            if (y0 > y1) { // swap the 2 points
                tmp = x0; x0 = x1; x1 = tmp;
                tmp = y0; y0 = y1; y1 = tmp;
                deltax = - deltax; deltay = -deltay;
            }
            deltaerr = Math.abs (((double)deltax) / deltay);   // Assume deltay != 0 (line is not horizontal),
            int x = x0;
            for (int y = y0; y <= y1; y++) {
                points.add(new Point(x, y));
                error += deltaerr;
                if (error >= 0.5) {
                    if (x0 < x1) x++; else x--;
                    error -= 1.0;
                }
            }
        }
        return points;
    }
}