//******************************************************************************
// life.java:	Applet
//
//******************************************************************************
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.awt.Event;

public class life extends Applet {

	static final int MAXSCALE = 6;

	Button clear,shake,step,loop;
	Button[] scale = new Button[MAXSCALE];

	Random rnd = new Random();

	static final int DRAWPIXELS = 320;
	static final int GRIDWIDE = 320;
	static final int GRIDHIGH = 320;
    static final int REPAINT_TICKS = 100;	// 10 times a second

	boolean[][] state = new boolean[GRIDWIDE][GRIDHIGH];
	boolean[][] newState = new boolean[GRIDWIDE][GRIDHIGH];

	int gridValue = 80;
	int[] scaleValue = {10,20,40,80,160,320};
    boolean doLoop = false;

//--- constructor ---
	public life(){
		clearGrid();
	}

	public void init(){
    	setLayout(null);
     	resize(320,350);
		buildTools();
		moveTools();
	}

//--- paint functions ---
    public void update(Graphics g){
    	try {paint(g);}
        catch(Exception ex){ex.printStackTrace();}
        if (doLoop) {
        	advanceState();
            repaint(REPAINT_TICKS);
        }
    }

	public void paint(Graphics g){
	int wide,high;

		g.setColor(Color.white);
		g.fillRect(0,0,320,400);

		g.setColor(Color.blue);
		wide = GRIDWIDE / gridValue;
		high = GRIDHIGH / gridValue;

		for (int i=0;i<gridValue;i++) {
			for (int j=0;j<gridValue;j++) {
				if (state[i][j]) 
					g.fillRect(i*wide,30+j*high,wide,high);
			}
		}
	}

	public boolean action(Event e,Object t){
	int i;

		if (e.id==e.ACTION_EVENT) {
			if (e.target==clear) clearGrid();
			if (e.target==shake) shakeGrid();
			if (e.target==step) advanceState();
            if (e.target==loop) doLoop = !doLoop;

			for (i=0;i<MAXSCALE;i++) if (e.target==scale[i])
				gridValue = scaleValue[i];

			repaint();
		}
		return false;
	}


	boolean dragState;

	public boolean handleEvent(Event e){

		switch (e.id) {

			case Event.KEY_PRESS:
				advanceState();
				break;

			case Event.MOUSE_DOWN:
				dragState = changeState(e.x,e.y);
				break;

			case Event.MOUSE_DRAG:
				setState(e.x,e.y,dragState);
				break;
		}

		return super.handleEvent(e);
	}

//--- tool functions ---
	public void buildTools(){
	int i,val;

		add(clear = new Button("Clear"));
		add(shake = new Button("Shake"));
		add(step = new Button("Step"));
		add(loop = new Button("Loop"));

		add(scale[0] = new Button("1"));
		add(scale[1] = new Button("2"));
		add(scale[2] = new Button("4"));
		add(scale[3] = new Button("8"));
		add(scale[4] = new Button("16"));
		add(scale[5] = new Button("32"));
	}

	public void moveTools(){
	int i;

		clear.reshape(5,5,30,20);
		shake.reshape(40,5,40,20);
		step.reshape(85,5,30,20);
		loop.reshape(120,5,30,20);

		for (i=0;i<MAXSCALE;i++) scale[i].reshape(170+i*25,7,20,14);
	}

//--- grid functions ---
	public void clearGrid(){
		for (int i=0;i<GRIDWIDE;i++) 
			for (int j=0;j<GRIDHIGH;j++)
				state[i][j] = false;

		state[41][39] = true;
		state[40][39] = true;
		state[40][40] = true;
		state[39][40] = true;
		state[40][41] = true;
		repaint();
	}


	public void shakeGrid(){
		for (int i=0;i<GRIDWIDE;i++) 
			for (int j=0;j<GRIDHIGH;j++)
				state[i][j] = ((rnd.nextInt()&1)==1);
		repaint();
	}


	public boolean changeState(int x,int y){
	int wide,high;

		wide = GRIDWIDE / gridValue;
		x = x / wide;
		if (x<0 || x>=gridValue) return false;

		high = GRIDHIGH / gridValue;
		y = (y-30) / high;
		if (y<0 || y>=gridValue) return false;

		state[x][y] = (state[x][y]?false:true);
		repaint();
		return state[x][y];
	}


	public void setState(int x,int y,boolean val){
	int wide,high;

		wide = GRIDWIDE / gridValue;
		x = x / wide;
		if (x<0 || x>=gridValue) return;

		high = GRIDHIGH / gridValue;
		y = (y-30) / high;
		if (y<0 || y>=gridValue) return;

		state[x][y] = val;
		repaint();
	}


//--- advance grid ---
	int[] dx = {0,1,1,1,0,-1,-1,-1};
	int[] dy = {-1,-1,0,1,1,1,0,-1};

	public void advanceState(){
	int i,j,di,dj,dir,count;

		for (i=0;i<gridValue;i++) {
			for (j=0;j<gridValue;j++) {

				count = 0;

				for (dir=0;dir<8;dir++) {
					di = i + dx[dir];
					if (di<0 || di>=gridValue) continue;
					dj = j + dy[dir];
					if (dj<0 || dj>=gridValue) continue;
					if (state[di][dj]) count++;
				}
				
				if (state[i][j])	
					newState[i][j] = (count==2 || count==3);
				else				
					newState[i][j] = (count==3);
			}
		}

		for (i=0;i<gridValue;i++) {
			for (j=0;j<gridValue;j++) {
				state[i][j] = newState[i][j];
			}
		}
	}
}