// FlipFlop_soln.java
// Raja Sooriamurthi

// An applet using the JDK 1.1 event model 
// to play the game of "Lights Out" 
//
// 1999/11/03  Initial version

/*
<applet code=FlipFlop_soln.class height=500 width=500></applet>
*/

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class FlipFlop_soln extends Applet 
   {
       int gameSize    = 5;    
       int numButtons  = gameSize*gameSize;
       int buttonSize  = 65; 

       Color ON_COLOR   = Color.red;
       Color OFF_COLOR  = Color.green;
       Color SOLN_COLOR = Color.pink;

    
       private boolean[] state;
       // state will point to either one of the below
       // depending on the mode
       private boolean[] playState, solveState;
       private  Button[] buttons;


       private void playMode()  
          { 
          state = playState; 
          }

       private boolean isPlayMode()
         {
         return( state == playState );
         }

       private void solveMode() 
          { 
          // copy the current play state
          for( int i=0; i<numButtons; i++ ) 
             {
             solveState[i] = playState[i];
             }
          state = solveState; 
          }


       public void init() 
          {
          // all initialized to false
          playState    = new boolean[ numButtons ]; 
          solveState   = new boolean[ numButtons ]; 
          buttons      = new  Button[ numButtons ];
          playMode();

          setLayout( new BorderLayout() );
          setBackground( Color.cyan ); 
   
          Panel p0 = new Panel();
          p0.setLayout( new FlowLayout(FlowLayout.CENTER, 60, 10) );
          Button startButton = new Button( "Start" );
          startButton.setBackground( Color.blue );
          startButton.setForeground( Color.red );
          startButton.addActionListener( new StartButtonL() );
          p0.add( startButton );
          Button solveButton = new Button( "Solve" );
          solveButton.setBackground( Color.blue );
          solveButton.setForeground( Color.red );
          solveButton.addActionListener( new SolveButtonL() );
          p0.add( solveButton );
          // *** "North" is case sensitive !!
          add( "North", p0 );

          Panel p1 = new Panel();
          p1.setLayout( new GridLayout(gameSize, gameSize, 5, 5) );
          for( int i = 0; i < numButtons; i++) 
             {
             buttons[i] = new Button( Integer.toString(i) );
             buttons[i].setSize( buttonSize, buttonSize );
             buttons[i].addActionListener( new ButtonL() );
             buttons[i].setBackground( OFF_COLOR );
             p1.add( buttons[i] );
             }
          // *** "Center" is case sensitive !!
          add( "Center", p1 );
          }

       // *********************************
       // A listener for the "start" button
       // *********************************

       class StartButtonL implements ActionListener 
           {
           public void actionPerformed (ActionEvent e) 
              {
              playMode();
              for( int i=0; i<numButtons; i++ ) 
                 { 
                 // randomly simulate clicking a button with 50/50 chance
                 if( Math.random() > 0.5 ) click( i );
                 }
              }
           }

       // *********************************
       //  A listener for the "solve" button
       // *********************************

       class SolveButtonL implements ActionListener 
           {
           public void actionPerformed (ActionEvent e) 
              {
              solve();
              }
           }

       // ****************************
       // Listeners for each button
       // ****************************

       class ButtonL implements ActionListener 
          {
          public void actionPerformed (ActionEvent e) 
             {
             int i = Integer.parseInt( e.getActionCommand() );
             click( i );
             }
          }

       // *************************
       // Click
       // *************************
       // Click toggles button i as well as each of its
       // neighbors on its four sides -if- they exist

       private void click( int i ) 
          {
          // toggle the clicked button
          System.out.println( "Clicked " + i );
          toggle( i );
          // toggle the left
          if( i%gameSize != 0 )             toggle( i-1 );
          // toggle the right
          if( i%gameSize < gameSize-1 )     toggle( i+1 );
          // toggle the below
          if( i >= gameSize )               toggle( i-gameSize );
          // toggle the above
          if( i < numButtons-gameSize )     toggle( i+gameSize );
          repaint();
          }
    
       // *************************
       //     toggle
       // *************************
       private void toggle( int i ) 
          {
          state[i] = !state[i];
          if( isPlayMode() ) updateButton( i );
          }


       // *************************
       //     updateButton
       // *************************
       private void updateButton( int i ) 
          {
          buttons[i].setBackground( state[i] ? ON_COLOR : OFF_COLOR );
          }


       // *************************
       //  solve
       // *************************
       private void solve()
          {
          int limit = (int) Math.pow( 2, gameSize );

          for( int i = 0; i<limit; i++ ) 
             {
             System.out.println("i --------------= " + i );
             solveMode();
             showGame();
             clickFirstRow( i );
             chaseLights();
             if( gameSolved() ) 
                {
                System.out.println("***** solved *****");
                showGame();
                solveFirstRow( i );
                playMode();
                return;
                } 
             } 
          System.out.println("!!!!failed!!!!!");
          playMode();
          } 
       

       // ******************************
       //         solveFirstRow
       // ******************************

       private void solveFirstRow( int n )
          {
          int i = gameSize-1;

          while( n > 0 ) 
             {
             if( n%2 == 1 ) 
                {
                buttons[i].setBackground( SOLN_COLOR );
                }
             n = n/2;
             i-- ;
             }
          } 


       // ******************************
       //         clickFirstRow
       // ******************************
       private void clickFirstRow( int n ) 
          {
          int i = gameSize-1;

          while( n > 0 ) 
             {
             if( n%2 == 1 ) 
                {
                click( i );
                }
             n = n/2;
             i-- ;
             }
          } 


       // ******************************
       //         gameSolved
       // ******************************
       private boolean gameSolved() 
          {
          for( int i=0; i<numButtons; i++ ) 
             {
             // if even one button is set the game has not been solved
             if( state[i] ) return false;
             }
          return true;
          }


       // ******************************
       //         chaseLights
       // ******************************
       private void chaseLights() 
          {
          System.out.println("==== chasing lights ====");
          for( int i=0; i<numButtons-gameSize; i++ ) 
             {
             if( state[i] ) 
                {
                // click the button directly below i
                click( i+gameSize );
                }
             } 
          }


       // ******************************
       //         showGame
       // ******************************
       // just for debugging
       private void showGame()
          {
          for( int i=0; i<numButtons; i++ ) 
             {
             System.out.print( state[i] ? "*" : "." );
             if( (i+1)%gameSize == 0 ) System.out.println();
             } 
          } 
   }