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

public class NoteBook6 extends JFrame {
	private JMenuItem menuOpen;

	private JMenuItem menuSave;

	private JMenuItem menuSaveAs;

	private JMenuItem menuClose;

	private JMenu editMenu;

	private JMenuItem menuCut;

	private JMenuItem menuCopy;

	private JMenuItem menuPaste;

	private JMenuItem menuAbout;

	private JTextArea textArea;

	private JLabel stateBar;

	private JFileChooser fileChooser;

	private JPopupMenu popUpMenu;

	public NoteBook6() {
		super("新建文本文件");
		setUpUIComponent();
		setUpEventListener();
		setVisible(true);
	}

	private void setUpUIComponent() {
		setSize(640, 480);

		// 菜單欄 
		JMenuBar menuBar = new JMenuBar();

		// 設置「文件」菜單 
		JMenu fileMenu = new JMenu("文件");
		menuOpen = new JMenuItem("打開");
		// 快捷鍵設置 
		menuOpen.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,
				InputEvent.CTRL_MASK));
		menuSave = new JMenuItem("保存");
		menuSave.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,
				InputEvent.CTRL_MASK));
		menuSaveAs = new JMenuItem("另存為");

		menuClose = new JMenuItem("關閉");
		menuClose.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q,
				InputEvent.CTRL_MASK));

		fileMenu.add(menuOpen);
		fileMenu.addSeparator(); // 分隔線 
		fileMenu.add(menuSave);
		fileMenu.add(menuSaveAs);
		fileMenu.addSeparator(); // 分隔線 
		fileMenu.add(menuClose);

		// 設置「編輯」菜單 
		JMenu editMenu = new JMenu("編輯");
		menuCut = new JMenuItem("剪切");
		menuCut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X,
				InputEvent.CTRL_MASK));
		menuCopy = new JMenuItem("復制");
		menuCopy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,
				InputEvent.CTRL_MASK));
		menuPaste = new JMenuItem("粘貼");
		menuPaste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_V,
				InputEvent.CTRL_MASK));
		editMenu.add(menuCut);
		editMenu.add(menuCopy);
		editMenu.add(menuPaste);

		// 設置「關于」菜單 
		JMenu aboutMenu = new JMenu("關于");
		menuAbout = new JMenuItem("關于記事本");
		aboutMenu.add(menuAbout);

		menuBar.add(fileMenu);
		menuBar.add(editMenu);
		menuBar.add(aboutMenu);

		setJMenuBar(menuBar);

		// 文字編輯區域 
		textArea = new JTextArea();
		textArea.setFont(new Font("宋體", Font.PLAIN, 16));
		textArea.setLineWrap(true);
		JScrollPane panel = new JScrollPane(textArea,
				ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
				ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);

		Container contentPane = getContentPane();
		contentPane.add(panel, BorderLayout.CENTER);

		// 狀態欄 
		stateBar = new JLabel("未修改");
		stateBar.setHorizontalAlignment(SwingConstants.LEFT);
		stateBar.setBorder(BorderFactory.createEtchedBorder());
		contentPane.add(stateBar, BorderLayout.SOUTH);

		popUpMenu = editMenu.getPopupMenu();
		fileChooser = new JFileChooser();
	}

	private void setUpEventListener() {
		// 按下窗口關閉鈕事件處理 
		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				closeFile();
			}
		});

		// 菜單 - 打開 
		menuOpen.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				openFile();
			}
		});

		// 菜單 - 保存 
		menuSave.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				saveFile();
			}
		});

		// 菜單 - 另存為 
		menuSaveAs.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				saveFileAs();
			}
		});

		// 菜單 - 關閉文件 
		menuClose.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				closeFile();
			}
		});

		// 菜單 - 剪切 
		menuCut.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				cut();
			}
		});

		// 菜單 - 復制 
		menuCopy.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				copy();
			}
		});

		// 菜單 - 粘貼 
		menuPaste.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				paste();
			}
		});

		// 菜單 - 關于 
		menuAbout.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				// 顯示對話框 
				JOptionPane.showOptionDialog(null, "程序名稱:\n NoteBook \n"
						+ "簡介:\n 一個簡單的文字編輯器\n", "關于NoteBook",
						JOptionPane.DEFAULT_OPTION,
						JOptionPane.INFORMATION_MESSAGE, null, null, null);
			}
		});

		// 編輯區鍵盤事件 
		textArea.addKeyListener(new KeyAdapter() {
			public void keyTyped(KeyEvent e) {
				processTextArea();
			}
		});

		// 編輯區鼠標事件 
		textArea.addMouseListener(new MouseAdapter() {
			public void mouseReleased(MouseEvent e) {
				if (e.getButton() == MouseEvent.BUTTON3)
					popUpMenu.show(editMenu, e.getX(), e.getY());
			}

			public void mouseClicked(MouseEvent e) {
				if (e.getButton() == MouseEvent.BUTTON1)
					popUpMenu.setVisible(false);
			}
		});
	}

	private void openFile() {
		if (isCurrentFileSaved()) { // 文件是否為保存狀態 
			open(); // 打開 
		} else {
			// 顯示對話框 
			int option = JOptionPane.showConfirmDialog(null, "文件已修改，是否保存？",
					"保存文件？", JOptionPane.YES_NO_OPTION,
					JOptionPane.WARNING_MESSAGE, null);
			switch (option) {
			// 確認文件保存 
			case JOptionPane.YES_OPTION:
				saveFile(); // 保存文件 
				break;
			// 放棄文件保存 
			case JOptionPane.NO_OPTION:
				open();
				break;
			}
		}
	}

	private boolean isCurrentFileSaved() {
		if (stateBar.getText().equals("未修改")) {
			return true;
		} else {
			return false;
		}
	}

	private void open() {
		// fileChooser 是 JFileChooser 的實例 
		// 顯示文件選取的對話框 
		int option = fileChooser.showDialog(null, null);

		// 使用者按下確認鍵 
		if (option == JFileChooser.APPROVE_OPTION) {
			/* 
			 TODO: 添加讀取文件的代碼 
			 */
		}
	}

	private void saveFile() {
		/* 
		 TODO: 添加保存文件的代碼 
		 */
	}

	private void saveFileAs() {
		/* 
		 TODO: 添加另存為的代碼 
		 */
	}

	private void closeFile() {
		// 是否已保存文件 
		if (isCurrentFileSaved()) {
			// 釋放窗口資源，而后關閉程序 
			dispose();
		} else {
			int option = JOptionPane.showConfirmDialog(null, "文件已修改，是否保存？",
					"保存文件？", JOptionPane.YES_NO_OPTION,
					JOptionPane.WARNING_MESSAGE, null);

			switch (option) {
			case JOptionPane.YES_OPTION:
				saveFile();
				break;
			case JOptionPane.NO_OPTION:
				dispose();
			}
		}
	}

	private void cut() {
		textArea.cut();
		stateBar.setText("已修改");
		popUpMenu.setVisible(false);
	}

	private void copy() {
		textArea.copy();
		popUpMenu.setVisible(false);
	}

	private void paste() {
		textArea.paste();
		stateBar.setText("已修改");
		popUpMenu.setVisible(false);
	}

	private void processTextArea() {
		stateBar.setText("已修改");
	}

	public static void main(String[] args) {
		new NoteBook6();
	}
}