package visual;

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

public class Wenbenbianjiqi extends JFrame implements ActionListener,MenuListener
{
	/**
	 * 
	 */
	private static final long serialVersionUID = 7090671861241983704L;

	JMenu file;
	JMenu exit;
	
	JMenuItem fileNew;
	JMenuItem fileOpen;
	JMenuItem fileClose;
	JMenuItem fileSave;
	JMenuItem fileSaveAs;
	JMenuItem exit1;
	
	JTextArea text;
	
	String title="File IO";
	
	JFileChooser chooser;
	
	String fileName=null;
	
	Container con;
	
	public Wenbenbianjiqi()
	{
		setTitle(title);
		setSize(300,300);
		
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		
		fileNew=new JMenuItem("新建",'N');
		fileOpen=new JMenuItem("打開",'O');
		fileClose=new JMenuItem("關閉",'C');
		fileSave=new JMenuItem("保存",'S');
		fileSaveAs=new JMenuItem("另存為...");
		fileSaveAs.setDisplayedMnemonicIndex(5);
		exit1 = new JMenuItem("退出");		
		
		
		fileNew.addActionListener(this);
		fileOpen.addActionListener(this);
		fileClose.addActionListener(this);
		fileSave.addActionListener(this);
		fileSaveAs.addActionListener(this);
		exit1.addActionListener(this);
		
		
		file=new JMenu("File(F)");
		file.setMnemonic('f');
		file.addMenuListener(this);
		file.add(fileNew);
		file.add(fileOpen);
		file.add(fileClose);
		file.addSeparator();
		file.add(fileSave);
		file.add(fileSaveAs);
		file.addSeparator();
		//file.add(exit);
		
		exit=new JMenu("Exit(E)");
		exit.add(exit1);
		
		
		JMenuBar bar=new JMenuBar();
		bar.setBackground(Color.pink);
		bar.add(file);
		bar.add(exit);
		
		setJMenuBar(bar);
		
		text=new JTextArea();
		text.setBackground(Color.orange);
		con=getContentPane();
		con.add(new JScrollPane(text));
		showEditState(false);

		chooser=new JFileChooser();
		
		setVisible(true);
		//setExtendedState(MAXIMIZED_BOTH);
	}
	
	public void menuSelected(MenuEvent event)
	{
		fileClose.setEnabled(!getTitle().equals(title));
		fileSave.setEnabled(!getTitle().equals(title));
		fileSaveAs.setEnabled(!getTitle().equals(title));
	}
	
	public void menuDeselected(MenuEvent event){}
	
	public void menuCanceled(MenuEvent event){}
	
	public void actionPerformed(ActionEvent event)
	{	
		if (event.getSource()==fileNew)
		{
			fileName=chooser.getCurrentDirectory()+"\\noname.txt";
			setTitle(title+" - "+fileName);
			
			showEditState(true);
			text.setText(null);
			text.requestFocus();
		}
		
		if (event.getSource()==fileOpen)
		{
			if (JFileChooser.APPROVE_OPTION==chooser.showOpenDialog(null))
			{
				fileName=chooser.getSelectedFile().getAbsolutePath();
				setTitle(title+" - "+fileName);
				
				showEditState(true);
				text.setText(readFile());
				text.setCaretPosition(0);
			}
		}
		
		if (event.getSource()==fileClose)
		{
			writeFile(text.getText());
			showEditState(false);
			setTitle(title);
		}

		if (event.getSource()==fileSave)
		{
			writeFile(text.getText());
		}

		if (event.getSource()==fileSaveAs)
		{
			if (JFileChooser.APPROVE_OPTION==chooser.showSaveDialog(null))
			{
				fileName=chooser.getSelectedFile().getAbsolutePath();
				setTitle(title+" - "+fileName);
				
				writeFile(text.getText());
			}
		}

		if (event.getSource()==exit1)
		{
			System.exit(0);
		}
	}
	
	public void showEditState(boolean b)
	{
		con.setVisible(b);
		con.validate();
	}
	
	public String readFile()
	{
		File file=new File(fileName);
		
		int len=(int)file.length();
		byte[] buf=new byte[len];

		try
		{
			FileInputStream in=new FileInputStream(file);
			in.read(buf);
			in.close();
		}
		catch (IOException e)
		{
			JOptionPane.showMessageDialog(null,"讀取文件"+fileName+"時出現錯誤！");
		}
		
		return new String(buf);
	}
	
	public void writeFile(String text)
	{
		File file=new File(fileName);
		
		int len=text.length();
		byte[] buf=new byte[len];
		buf=text.getBytes();

		try
		{
			FileOutputStream out=new FileOutputStream(file);
			out.write(buf);
			out.close();
		}
		catch (IOException e)
		{
			JOptionPane.showMessageDialog(null,"寫入文件"+fileName+"時出現錯誤！");
		}
	}
	
	public static void main(String[] args)
	{
		new Wenbenbianjiqi();
	}
}