//
// This is a small russian game "Perevertishi"
//
import java.awt.*;
import java.applet.*;
import java.awt.event.*;

//
// class Rotations
//
public class Rotations extends Applet implements MouseListener, KeyListener
{
	Label label1   = new Label();
	Color colors[] = new Color[6]; // colors of cube sides
	
	private int free = 4;	// position of free place
	int attitude[]={0,0,0,0,0,0,0,0,0}; // attitudes of cubes
	
	int history[] = new int[16000]; // commands history
	int hi;     // history index
	int hi_max; // length of commands history
	
	// cubes attitude information
	int cube_info[] = {
		0,1,2,  5,20, 7,21,
		3,1,5,  6,21, 4,20,
		3,4,2,  7,23, 5,22,
		0,4,5,  4,22, 6,23,
		1,0,5,  1, 9, 3, 8,
		4,0,2,  2, 8, 0, 9,
		4,3,5,  3,10, 1,11,
		1,3,2,  0,11, 2,10,
		2,0,1, 13, 4,15, 5,
		5,0,4, 14, 5,12, 4,
		5,3,1, 15, 7,13, 6,
		2,3,4, 12, 6,14, 7,
		0,2,4,  9,17,11,16,
		3,2,1, 10,16, 8,17,
		3,5,4, 11,18, 9,19,
		0,5,1,  8,19,10,18,
		1,2,0, 21,12,23,13,
		4,2,3, 22,13,20,12,
		4,5,0, 23,15,21,14,
		1,5,3, 20,14,22,15,
		2,1,3, 17, 1,19, 0,
		5,1,0, 18, 0,16, 1,
		5,4,3, 19, 2,17, 3,
		2,4,0, 16, 3,18, 2
	};
	
	// The entry point for the applet. 
	public void init()
	{
//		this.setLayout(new FlowLayout());
		this.setBackground(Color.white);
		label1.setText("0 ");
		this.add(label1);
		
		for(int i=0; i<6; i++)
			colors[i] = Color.getHSBColor(i/6.0f, 0.99f, 0.8f);
		
		addMouseListener(this);
		addKeyListener(this);
	}
	
	private final int size   = 60; // total size of cube place
	private final int border = 4;  // width of cube border
	private final int gap    = 2;  // gap between cubes
	private final int center = size-border*2-gap; // width of central cube side
	private final int field  = size*3+gap+1;        // width of game field
	private final int origin = 40;
	
//	public void start(){label1.setLocation(gap, field+50);}

	public void paint(Graphics g)
	{	
		g.setPaintMode();
		g.setColor(Color.lightGray);
		g.drawRect(origin,origin,field,field);
		
		for(int pos=0; pos<9; pos++)
		{
			int x = origin+gap+border+1 + size*(pos%3);
			int y = origin+gap+border+1 + size*(pos/3);
			
			if(pos==free){
				g.setColor(Color.white);
				g.fillRect(x-border,  y-border, size, size);
				continue;
			}

			int i = attitude[pos]*7;
			int c;
			g.setColor(colors[cube_info[i++]]);
			g.fillRect(x, y, center, center);
			g.setColor(colors[c=cube_info[i++]]);
			g.fillRect(x, y-border, center, border);
			g.setColor(colors[(c+3)%6]);
			g.fillRect(x, y+center, center, border);
			g.setColor(colors[c=cube_info[i]]);
			g.fillRect(x-border, y, border, center);
			g.setColor(colors[(c+3)%6]);
			g.fillRect(x+center, y, border, center);
		}
	}

	public void mouseReleased(MouseEvent e){}
	public void mouseEntered(MouseEvent e){}
	public void mouseExited(MouseEvent e){}
	public void mouseClicked(MouseEvent e){}

	public void mousePressed(MouseEvent e){
		int x=(e.getX()-origin-gap)/size;
		int y=(e.getY()-origin-gap)/size;
		if(0<=x && x<=2 && 0<=y && y<=2)
		{
			int pos = y*3+x;
			int dir;
			switch(free-pos){
			case -3: dir=0; break;
			case  1: dir=1; break;
			case  3: dir=2; break;
			case -1: dir=3; break;
			default: return;
			}
			history[hi++] = dir;
			hi_max = hi;
			move(dir);
		}
	}
	
	private final void move(int dir)
	{
		final int arr[] = {-3,1,3,-1};
		int next = (free-arr[dir]);
		if(next<0 || next>8 || ((dir&1)!=0 && (free/3!=next/3) )){
			hi_max = --hi;
			return;
		}
		attitude[free] = cube_info[attitude[next]*7+3+dir];
		free = next;
		label1.setText(""+hi);
//		repaint();
		paint(getGraphics());
	}
	
	public void keyReleased(KeyEvent e){}
	public void keyTyped(KeyEvent e){}
	
	public void keyPressed(KeyEvent e)
	{
		int dir;
		
		switch(e.getKeyCode())
		{
		case e.VK_R:
		case e.VK_Z:
			// Do Redo operation on keys "R", "Z", "Shift-Ctrl-Z" and other
			if( e.isShiftDown() || !e.isControlDown()) 
			{
				if(hi<hi_max) move( history[hi++] );
				return;
			}
		case e.VK_U: 
			// Do Undo operation on keys "U", "Ctr-Z", and other
			if(hi>0) move( (history[--hi]+2)%4 );
			return;
		case e.VK_UP:    dir=0; break;
		case e.VK_RIGHT: dir=1; break;
		case e.VK_DOWN:  dir=2; break;
		case e.VK_LEFT:  dir=3; break;
		default: return;
		}
		history[hi++] = dir;
		hi_max = hi;
		move(dir);
	}
}