// Puzzle.java
import java.awt.*;
import java.net.*;

public class Puzzle extends Panel
{
   private ColorButton[][] tile;
   private Image[] image;
   private int puzzleSize, dim;
   private PuzzleStarter ps;
   private int[] prevState;

   public Puzzle(PuzzleStarter _ps, int _puzzleSize)
   {
      super();
      ps = _ps;
      puzzleSize = _puzzleSize;
      dim = (int)Math.sqrt(puzzleSize);
      setSize(192, 192);
      tile = new ColorButton[dim][dim];
      image = new Image[puzzleSize];
      prevState = new int[puzzleSize];
      for(int i = 1; i < puzzleSize; i++)
        prevState[i - 1] = i;
      prevState[puzzleSize - 1] = 0;

      try
      {
         String fileBase, fileStr;
         if (puzzleSize == 9)
           fileBase = "Images/8Puzzle/shrksign_";
         else
           fileBase = "Images/15Puzzle/shrksign_";
         if (ps != null)
           for(int i = 0; i < puzzleSize; i++)
           {
              fileStr = fileBase;
              if (i <= 9)
                fileStr += "0";
              trackImage(i, getToolkit().getImage(
                            new URL(ps.getCodeBase() + fileStr + 
                            Integer.toString(i) + ".gif")));
           }
         else
           for(int i = 0; i < puzzleSize; i++)
           {
              fileStr = fileBase;
              if (i <= 9)
                fileStr += "0";
              trackImage(i, getToolkit().getImage(fileStr + 
                         Integer.toString(i) + ".gif"));
           }
      }
      catch (MalformedURLException mfe)
      {
         System.err.println("Error: " + mfe);
      }

      setLayout(new GridLayout(dim, dim));
      int pos = 1;
      for(int i = 0; i < dim; i++)
        for(int j = 0; j < dim; j++)
        {
           if (pos == puzzleSize)
             tile[i][j] = new ColorButton(image[0], 1, Color.blue);
           else
             tile[i][j] = new ColorButton(image[pos], 1, Color.blue);
           add(tile[i][j]);
           pos++;
        }
   }

   public void putInOrder()
   {
      int pos = 0;
      int[] state = new int[puzzleSize];
      for(int i = 1; i < puzzleSize; i++)
        state[i - 1] = i;
      state[puzzleSize - 1] = 0;
      for(int i = 0; i < dim; i++)
        for(int j = 0; j < dim; j++)
        {
           if (state[pos] != prevState[pos])
           {
              tile[i][j].setImage(image[state[pos]]);
              tile[i][j].repaint();
           }
           prevState[pos] = state[pos];
           pos++;
        }
   }

   public void setOrder(int[] state)
   {
      int pos = 0;
      for(int i = 0; i < dim; i++)
        for(int j = 0; j < dim; j++)
        {
           if (state[pos] != prevState[pos])
           {
              tile[i][j].setImage(image[state[pos]]);
              tile[i][j].repaint();
           }
           prevState[pos] = state[pos];
           pos++;
        }
   }

   private void trackImage(int index, Image _image)
   {
      image[index] = _image;
      MediaTracker tracker = new MediaTracker(this);
      tracker.addImage(image[index], 0);
      try
      {  
         tracker.waitForAll();
      }
      catch (InterruptedException ie)
      { 
         System.err.println("Image loading interrupted: " + ie);
      }
   }

}