import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.RasterFormatException;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import javax.imageio.ImageIO;

public class LangtonsAnt {

    private static final int SIZE = 2000;
    private static final int STEPS = 90000000;

    private static HashMap<Color, Character> map = new HashMap<>();
    private static Color[] cols;
    private static char[] turn;

    private static BufferedImage image = new BufferedImage(SIZE, SIZE, BufferedImage.TYPE_INT_RGB);
    private static Graphics2D g = image.createGraphics();

    public LangtonsAnt(){
        initColours("LLRR");
        startGrid();
        initMap();
        drawCol(SIZE/2, SIZE/2, 0);
        saveToFile();
    }

    public static void main(String[] args) {
        new LangtonsAnt();
    }

    private static void initColours(String turns){
        turn = new char[turns.trim().length()];
        cols = new Color[turns.trim().length()];
        for(int i = 0; i < turns.length(); i++){
            turn[i] = turns.charAt(i);
            cols[i] = new java.awt.Color((int)(Math.random()*256), (int)(Math.random()*256), (int)(Math.random()*256));
        }
        cols[0] = Color.WHITE;
    }

    private static void initMap(){
        for(int i = 0; i < cols.length; i++)    map.put(cols[i], turn[i]);
    }

    private static void drawBW(int x, int y, int dir){
        for(int i = 0; i < STEPS; i++){
            if(x >= SIZE || y >= SIZE || x <= 0 || y <= 0)  break;
            if(new Color(image.getRGB(x, y)).equals(Color.WHITE)){
                dir = dir != 3 ? dir+1 : 0;
                g.setColor(Color.BLACK);
                g.drawLine(x, y, x, y);
            } else{
                dir = dir != 0 ? dir-1 : 3;
                g.setColor(Color.WHITE);
                g.drawLine(x, y, x, y);
            }
            if(dir == 0)    y++;
            else if(dir == 1)   x++;
            else if(dir == 2)   y--;
            else x--;
        }
    }

    private static void drawCol(int x, int y, int dir){
        Color currPixel;
        for(int i = 0; i < STEPS; i++){
            if(x >= SIZE || y >= SIZE || x <= 0 || y <= 0)  break;
            currPixel = new Color(image.getRGB(x, y));
            dir = map.get(currPixel) == 'L' ? (dir != 3 ? dir+1 : 0) : (dir != 0 ? dir-1 : 3);
            g.setColor(getNextColour(currPixel));
            g.drawLine(x, y, x, y);

            if(dir == 0)    y++;
            else if(dir == 1)   x++;
            else if(dir == 2)   y--;
            else x--;
        }
    }

    private static Color getNextColour(Color currColour){
        for(int i = 0; i < cols.length; i++)
            if(cols[i].equals(currColour))
                return i == cols.length-1 ? cols[0] : cols[i+1];

                return null;
    }

    private static void startGrid(){
        g.setColor(cols[0]);
        g.fillRect(0, 0, SIZE, SIZE);
    }

    private static void saveToFile(){
        try {
            ImageIO.write(image, "png", new File("Ants.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}