//Subsequences.java
// 2^N of them.  aka powerset

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;


public class Subsequences extends JApplet {

    JTextField inputStringField;
    JTextArea listArea;
    JLabel errorLabel;

    java.util.List subsAlphaDupsList;
    java.util.List subsSizeDupsList;
    TreeSet subsAlphaUniqSet;
    java.util.List subsSizeUniqList;

    JRadioButton radioAlphaButton, radioSizeButton;
    ButtonGroup buttonGroup;
    JRadioButton radioUniqueButton, radioDupsButton;
    ButtonGroup buttonGroup2;
    RadioButtonHandler radioButtonHandler;


    public void init() {
	Container container = getContentPane();
	int panelRowsSize = 2;
	container.setLayout( new GridLayout( 1, panelRowsSize) );

	JPanel [] panelRows = new JPanel[panelRowsSize];

	//left side panel
	panelRows[0] = new JPanel();
	container.add( panelRows[0] );
	panelRows[0].setLayout( new GridLayout( 2, 1 ) );

	JPanel topleftPanel = new JPanel();
	panelRows[0].add( topleftPanel );

	JPanel bottomleftPanel = new JPanel();
	panelRows[0].add( bottomleftPanel );
	bottomleftPanel.setLayout( new GridLayout( 1, 2 ) );

	JPanel bottomleftPanelleft = new JPanel();
	bottomleftPanel.add( bottomleftPanelleft );
	bottomleftPanelleft.setLayout( new GridLayout( 2, 1 ) );

	JPanel bottomleftPanelright = new JPanel();
	bottomleftPanel.add( bottomleftPanelright );
	bottomleftPanelright.setLayout( new GridLayout( 2, 1 ) );

	//right side panel
	panelRows[1] = new JPanel();
	panelRows[1].setLayout( new FlowLayout() );
	container.add( panelRows[1] );

	subsAlphaDupsList = new ArrayList();

	Font bigFont = new Font( "Monospaced", Font.BOLD, 16 );
	TextFieldHandler handleTextField = new TextFieldHandler();

	JLabel inputNLabel = new JLabel( "String" );
	inputNLabel.setFont( bigFont );
	topleftPanel.add( inputNLabel );

	inputStringField = new JTextField( 30 );
	inputStringField.setFont( bigFont );
	topleftPanel.add( inputStringField );
	inputStringField.addActionListener( handleTextField );

	errorLabel = new JLabel( "" );
	topleftPanel.add( errorLabel );


	radioAlphaButton = new JRadioButton( "Alphabetic order" );
	bottomleftPanelleft.add( radioAlphaButton );
	radioButtonHandler = new RadioButtonHandler();
	radioAlphaButton.addItemListener( radioButtonHandler ); 

	radioSizeButton = new JRadioButton( "By size order" );
	bottomleftPanelleft.add( radioSizeButton );
	radioSizeButton.addItemListener( radioButtonHandler ); 

	//radioBinaryButton = new JRadioButton( "By binary number order" );
	//bottomleftPanelleft.add( radioBinaryButton );
	//radioBinaryButton.addItemListener( radioButtonHandler ); 

	buttonGroup = new ButtonGroup();
	buttonGroup.add(radioAlphaButton);
	buttonGroup.add(radioSizeButton);
	//buttonGroup.add(radioBinaryButton);


	radioUniqueButton = new JRadioButton( "Uniques only" );
	bottomleftPanelright.add( radioUniqueButton );
	radioUniqueButton.addItemListener( radioButtonHandler ); 

	radioDupsButton = new JRadioButton( "Dups OK" );
	bottomleftPanelright.add( radioDupsButton );
	radioDupsButton.addItemListener( radioButtonHandler ); 

	buttonGroup2 = new ButtonGroup();
	buttonGroup2.add(radioUniqueButton);
	buttonGroup2.add(radioDupsButton);


	listArea = new JTextArea( 16, 30 );
        Font smallFont = new Font( "Monospaced", Font.BOLD, 12 );
        listArea.setFont( smallFont );
        JScrollPane listScroll = new JScrollPane( listArea );
        panelRows[1].add( listScroll );
                                                                           
    }


    public void start() {
	inputStringField.requestFocusInWindow();
	radioAlphaButton.setSelected( true ); //check in handler if start()
	radioDupsButton.setSelected( true ); 
    }


    private class TextFieldHandler implements ActionListener {
        public void actionPerformed( ActionEvent event ) {

	    listArea.setText( "" );		    

	    String s = inputStringField.getText();
	    int n = s.length();

	    errorLabel.setText( "" );

	    if ( n > 31 ) {
		errorLabel.setText( "up to 31 chars only" );
		return;
	    }

             
	    char[] A=s.toCharArray();
            int two_n = 1 << n;
 
	    subsAlphaDupsList.clear();
            //generate in binary number order
            for (int i=0; i<=two_n-1; i++) {
                String subset = "";
                for (int j=0; j<n; j++)
                    if (((i>>j) & 1) == 1)
                        subset += "" + A[j];

                subsAlphaDupsList.add( subset );

	    }

	    //sort into alphabetic order
	    Collections.sort( subsAlphaDupsList );    //alpha & dups

	    subsSizeDupsList = new ArrayList( subsAlphaDupsList) ;
	    //sort into length order (stable by alpha)
	    Collections.sort( subsSizeDupsList, 
  	      new Comparator() {
		  public int compare (Object o1, Object o2) {
		      return ((String)o1).length() - ((String)o2).length();
		  }
	      }
			      );      //size & dups

	    //alphabetic and no dups
	    subsAlphaUniqSet = new TreeSet( subsAlphaDupsList );  //alpha & unique

	    //build ordered-by-sizes list.
	    subsSizeUniqList = new ArrayList( subsAlphaUniqSet );
	    
	    Collections.sort( subsSizeUniqList, 
  	      new Comparator() {
		  public int compare (Object o1, Object o2) {
		      return ((String)o1).length() - ((String)o2).length();
		  }
	      }
			      );      //size & unique
	    

	    radioButtonHandler.displaySubstrings();

	}
    }


    /*
    private void displaySizedSet() {
	listArea.setText( "" );

	for (int i=0; i<sizedSets.length; i++) {
	    //iterate over the sorted set of length 'i+1' strings
	    Iterator it = sizedSets[i].iterator();
	    while ( it.hasNext() )
		listArea.append( (String)it.next() + "\n" );
	}
    }
    */
    /*
    private void sizeSort( Set subsAlphaUniqSet ) {
	String s;
	int n = inputStringField.getText().length();

	//array of treesets:
	sizedSets = new TreeSet[n];
	for (int size=0; size<n; size++)    //assume are unique...OK
	    sizedSets[size] = new TreeSet();

	Iterator it = subsAlphaUniqSet.iterator();
	while ( it.hasNext() ) {
	    s = (String)it.next();
	    sizedSets[s.length()-1].add( s );
	}
    }
    */

    private class RadioButtonHandler implements ItemListener {
        public void itemStateChanged( ItemEvent event ) {
	    displaySubstrings();
	}


	public void displaySubstrings() {	    

	    if ( subsAlphaUniqSet != null ) {    //at start is null.  force text field entry first

		listArea.setText( "" );

		Iterator it=null;   //force init.
	    
		if ( radioAlphaButton.isSelected() )
		    if ( radioUniqueButton.isSelected() ) //Alpha and Unique
			it = subsAlphaUniqSet.iterator();
		    else     //Alpha and Dups
			it = subsAlphaDupsList.iterator();

		else      //if ( radioSizeButton.isSelected() ) 
		    if ( radioUniqueButton.isSelected() )  //Size and Unique
			it = subsSizeUniqList.iterator();
		    else  //Size and Dups
			it = subsSizeDupsList.iterator();

		while ( it.hasNext() )
		    listArea.append( (String)it.next() + "\n" );

	    }
	}
    }

}