/*
 * CommonWordApplet.java
 * Created on Feb 25, 2005
 */
package word;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

//7.83
//7.26

/**
 * An applet for search for common words.
 */
public final class CommonWordApplet extends JApplet implements ActionListener {
    
    private final CommonWordFinder treeFinder =
        	new CommonWordFinder(WordBagFactory.WORD_TREE_BAG_FACTORY);
    
    private final CommonWordFinder hashFinder =
    		new CommonWordFinder(WordBagFactory.WORD_HASH_BAG_FACTORY);
    
    private final ReaderRun READER_RUN = new ReaderRun();
    private final CommonRun COMMON_RUN = new CommonRun();
    
    private final JLabel urlLabel = new JLabel("URL: ");
    private final JTextField urlField  = new JTextField(30);
    private final JLabel numWordsLabel = new JLabel("# words: ");
    private final JTextField numWordsField  = new JTextField(3);
    private final JButton treeButton = new JButton("Tree-Based");
    private final JButton hashButton = new JButton("Hash-Based"); 
    private final JLabel statusLabel = new JLabel();
    private final JList wordList = new JList();
    
    private String text = null;
    private int numWords = 0;
    private CommonWordFinder finder = null;

    public CommonWordApplet() {}
    
    public void init() {
        JPanel urlPanel = new JPanel();
        urlPanel.add(urlLabel);
        urlPanel.add(urlField);
        
        JPanel searchPanel = new JPanel();
        searchPanel.add(numWordsLabel);
        searchPanel.add(numWordsField);
        searchPanel.add(treeButton);
        searchPanel.add(hashButton);
        
        treeButton.addActionListener(this);
        hashButton.addActionListener(this);
        
        JPanel statusPanel = new JPanel();
        statusPanel.add(statusLabel);
        statusLabel.setHorizontalAlignment(JLabel.CENTER);
        
        JScrollPane wordScroll = new JScrollPane(wordList);
        wordScroll.setPreferredSize(new Dimension(100, 50));
        
        Container contentPane = getContentPane();
        contentPane.setLayout(new BorderLayout());
        contentPane.add(urlPanel, BorderLayout.NORTH);
        contentPane.add(searchPanel, BorderLayout.CENTER);
        contentPane.add(statusPanel, BorderLayout.SOUTH);
        contentPane.add(wordScroll,  BorderLayout.EAST);
    }
    
    public void actionPerformed(ActionEvent e) {
        // disable the buttons
        setButtonsEnabled(false);
        
        // parse the number of words entered
        boolean numGood = false;
        try {
            numWords = Integer.parseInt(numWordsField.getText());
            if (numWords > 0) numGood = true;
        } catch (NumberFormatException ex) { /* numGood remain false */ }
        
        // if not a good number 
        if (!numGood) {
            setButtonsEnabled(true);
            statusLabel.setText("# words must be a non-negative integer");
            repaint();
            return;
        }
        
        // set the finder that was selected
        finder = e.getSource().equals(treeButton) ? treeFinder : hashFinder;
        
        // read in the url text
        statusLabel.setText("Reading URL text . . .");
        repaint();
        SwingUtilities.invokeLater(READER_RUN);
    }
    
    private void setButtonsEnabled(boolean enable) {
        treeButton.setEnabled(enable);
        hashButton.setEnabled(enable);
    }
    
    private class ReaderRun implements Runnable {
        
        public void run() {
            Reader r = null;
            // simpler code if presume there is an error
            boolean error = true;
            
            try {
                StringBuffer sb = new StringBuffer();
                URL url = new URL(urlField.getText());
                r = new BufferedReader(new InputStreamReader(url.openStream()));
                
                for(int c = r.read(); c != -1; c = r.read()) {
                    sb.append((char)c);
                }
                
                error = false;
                text = sb.toString();
                statusLabel.setText("Finding common words . . .");
            } catch (MalformedURLException ex) {
                statusLabel.setText("Malformed URL");
            } catch (IOException ex) {
                statusLabel.setText("Error reading from URL");
            } finally {
                if (r != null) {
                    try { r.close(); }
                    catch(IOException ignore) {}
                }
            }
            
            // find the common words
            if (error) setButtonsEnabled(true);
            repaint();
            if (!error) SwingUtilities.invokeLater(COMMON_RUN);
        }
    }
    
    private class CommonRun implements Runnable {
        
        public void run() {
            statusLabel.setText("Finding common words . . . ");
    	    long startTime = System.currentTimeMillis();
    	    List/*<WordCount>*/ commonWords = treeFinder.findCommonWords(text, numWords);
    	    long duration = System.currentTimeMillis() - startTime;
    	    statusLabel.setText("Finished: " + (duration / 1000.0) + " seconds");
            wordList.setListData(commonWords.toArray());
            setButtonsEnabled(true);
            repaint();
        }
    }
    
}