import javax.swing.*;
import java.awt.event.*;
import java.awt.Container;
import java.awt.BorderLayout;
import java.awt.Font;
import java.util.*;
import java.io.*;
import java.text.DateFormat;


public class Logger
extends JFrame
{
    private JTextArea text;
    private DateFormat format;
    private JFileChooser chooser;
    private JTextField alertFld;
    private JComboBox formChoice;
    private List eventList;
    private LoggerIO ioHndlr;
    private String eol;
    private Font logFont;
    
    private static final String EMPTY = "";
    private static final Date EARLIEST = new Date( 0L );
    
    public static final String [] formats = { "Text", "Data", "Object" };
    
    public static void main( String [] args )
    {
        Logger logger = new Logger( );
        logger.setVisible( true );
    }
    
    public Logger( )
    {
        super( "Logger" );
        ioHndlr = new LoggerIO( this );
        format = DateFormat.getDateTimeInstance( DateFormat.SHORT, DateFormat.MEDIUM );
        chooser = new JFileChooser();
        eventList = new LinkedList();
        eol = System.getProperty( "line.separator" );
        logFont = new Font( "SanSerif", Font.BOLD, 16 );
        setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        Container content = getContentPane();
        
        JPanel btnPanel = new JPanel();
        
        JLabel formLbl = new JLabel( "Format" );
        btnPanel.add( formLbl );
        
        formChoice = new JComboBox( formats );
        formChoice.setSelectedItem( "Text" );
        btnPanel.add( formChoice );
        
        JLabel space = new JLabel( "    " );
        btnPanel.add( space );
        
        JButton logBtn = new JButton( "Log" );
        logBtn.addActionListener( new ActionListener()
            {
                public void actionPerformed( ActionEvent e )
                { log(); }
            }
        );
        btnPanel.add( logBtn );
        
        JButton sumBtn = new JButton( "Summarize" );
        sumBtn.addActionListener( new ActionListener()
            {
                public void actionPerformed( ActionEvent e )
                { summarize(); }
            }
        );
        btnPanel.add( sumBtn );
        
        JButton clearBtn = new JButton( "Clear" );
        clearBtn.addActionListener( new ActionListener()
            {
                public void actionPerformed( ActionEvent e )
                { clear(); }
            }
        );
        btnPanel.add( clearBtn );
        
        JButton saveBtn = new JButton( "Save" );
        saveBtn.addActionListener( new ActionListener()
            {
                public void actionPerformed( ActionEvent e )
                { save(); }
            }
        );
        btnPanel.add( saveBtn );
        
        JButton loadBtn = new JButton( "Load" );
        loadBtn.addActionListener( new ActionListener()
            {
                public void actionPerformed( ActionEvent e )
                { load(); }
            }
        );
        btnPanel.add( loadBtn );
        
        JButton quitBtn = new JButton( "Quit" );
        quitBtn.addActionListener( new ActionListener()
            {
                public void actionPerformed( ActionEvent e )
                { quit(); }
            }
        );
        btnPanel.add( quitBtn );
        
        content.add( btnPanel, BorderLayout.NORTH );
        
        JPanel textPanel = new JPanel();
        text = new JTextArea( 20, 60 );
        text.setFont( logFont );
        text.setEditable( false );
        text.setText( EMPTY );
        JScrollPane scroller = new JScrollPane( text );
        textPanel.add( scroller );
        content.add( textPanel, BorderLayout.CENTER );
        
        alertFld = new JTextField( 60 );
        alertFld.setFont( logFont );
        content.add( alertFld, BorderLayout.SOUTH );
        
        pack();
    }
    
    void announce( String txt )
    {
        alertFld.setText( txt );
    }
    
    private void log()
    {
        Date now = new Date();
        eventList.add( now );
        text.append( format.format( now ) + eol );
    }
    
    private void summarize()
    {
        ListIterator iter = eventList.listIterator();
        boolean outOfOrder = false;
        Date previous = EARLIEST;
        int count = 0;
        
        while ( iter.hasNext() )
        {
            Date nDate = (Date) iter.next();
            if ( previous.after( nDate ) )
                outOfOrder = true;
            previous = nDate;
            count++;
        }
        StringBuffer sb = new StringBuffer();
        if ( outOfOrder )
            sb.append( "EVENTS OUT OF ORDER!! " );
        sb.append( "Number of events = " + count );
        alertFld.setText( sb.toString() );
    }
    
    private void clear()
    {
        text.setText( EMPTY );
        alertFld.setText( EMPTY );
        eventList = new LinkedList();
    }
    
    private void save()
    {
        File logFile = null;
        
        int confirm = chooser.showSaveDialog( this );
        if ( confirm == JFileChooser.APPROVE_OPTION )
        {
            logFile = chooser.getSelectedFile();
            String form = (String) formChoice.getSelectedItem();
            if ( form.equals( "Text" ) )
                ioHndlr.saveToText( eventList, logFile );
            else if ( form.equals( "Data" ) )
                ioHndlr.saveToData( eventList, logFile );
            else if ( form.equals( "Object" ) )
                ioHndlr.saveToObject( eventList, logFile );
            else
                alertFld.setText( "Choose a format" );
        }
    }
    
    private void load()
    {
        File logFile = null;
        
        int confirm = chooser.showOpenDialog( this );
        if ( confirm == JFileChooser.APPROVE_OPTION )
        {
            clear();
            logFile = chooser.getSelectedFile();
            String form = (String) formChoice.getSelectedItem();
            if ( form.equals( "Text" ) )
                eventList = ioHndlr.loadFromText( logFile );
            else if ( form.equals( "Data" ) )
                eventList = ioHndlr.loadFromData( logFile );
            else if ( form.equals( "Object" ) )
                eventList = ioHndlr.loadFromObject( logFile );
            else
                alertFld.setText( "Choose a format" );
            
            if ( eventList == null )
                eventList = new LinkedList();

            ListIterator iter = eventList.listIterator();
            while ( iter.hasNext() )
            {
                Date next = (Date) iter.next();
                text.append( format.format( next ) + eol );
            }
        }
    }
       
    private void quit()
    {
        System.exit( 0 );
    }
}