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

public class ImageViewer {
    private static final String version = "Version 1.0";
    private static JFileChooser fileChooser = new JFileChooser(System.getProperty("user.dir"));

    private JFrame frame;
    private ImagePanel imgPanel;
    private JLabel filenameLabel, statusLabel;
    private OFImage currentImage;

    public ImageViewer() {
        // TODO Auto-generated constructor stub
        currentImage = null;
        makeFrame();
    }

    private void makeFrame()
    {
        frame = new JFrame("ImageViewer");
        makeMenuBar(frame);

        Container contentPane = frame.getContentPane();
        contentPane.setLayout(new BorderLayout(6,6));

        filenameLabel = new JLabel();
        contentPane.add(filenameLabel,BorderLayout.NORTH);

        imgPanel = new ImagePanel();
        contentPane.add(imgPanel, BorderLayout.CENTER);

        statusLabel = new JLabel(version);
        contentPane.add(statusLabel, BorderLayout.SOUTH);

        showFilename(null);
        frame.pack();

        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        frame.setLocation(d.width/2 - frame.getWidth()/2, d.height/2 - frame.getHeight()/2);

        frame.setVisible(true);
    }

    private void makeMenuBar(JFrame frame)
    {
        final int SHORTCUT_MASK = Toolkit.getDefaultToolkit().getMenuShortcutKeyMask();

        JMenuBar menuBar = new JMenuBar();
        frame.setJMenuBar(menuBar);

        JMenu menu;
        JMenuItem item;

        menu = new JMenu("File");
        menuBar.add(menu);

        item = new JMenuItem("Open");
        item.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_0, SHORTCUT_MASK));
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                openFile();
            }
        });
        menu.add(item);

        item = new JMenuItem("Close");
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                close();
            }
        });

        menu.add(item);
        menu.addSeparator();

        item = new JMenuItem("Quit");
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                quit();
            }
        });

        menu.add(item);

        menu = new JMenu("Filter");
        menuBar.add(menu);

        item = new JMenuItem("Darker");
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                makeDarker();
            }
        });
        menu.add(item);

        item = new JMenuItem("Lighter");
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                makeLighter();
            }
        });
        menu.add(item);

        item = new JMenuItem("Threshold");
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                threshold();
            }
        });
        menu.add(item);

        menu = new JMenu("Help");
        menuBar.add(menu);

        item = new JMenuItem("About ImageViewer...");
        item.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                showAbout();
            }
        });
        menu.add(item);
    }

    private void openFile()
    {
        int returnVal = fileChooser.showOpenDialog(frame);
        if(returnVal != JFileChooser.APPROVE_OPTION)
        {
            return;
        }
        File selectedFile = fileChooser.getSelectedFile();
        currentImage = ImageFileManager.loadImage(selectedFile);

        if (currentImage == null)
        {
            JOptionPane.showMessageDialog(frame, "The file was not in a recognized image file format.","Image Load Error", JOptionPane.ERROR_MESSAGE);
            return;
        }
        imgPanel.setImage(currentImage);
        showFilename(selectedFile.getPath());
        showStatus("File Loaded.");
        frame.pack();
    }

    private void close()
    {
        currentImage = null;
        imgPanel.clearImage();
        showFilename(null);
    }

    private void quit()
    {
        System.exit(0);
    }

    private void showFilename(String filename)
    {
        if(filename == null)
        {
            filenameLabel.setText("No file displayed");
        }
        else
        {
            filenameLabel.setText("File: " + filename);
        }
    }

    private void showAbout()
    {
        JOptionPane.showMessageDialog(frame, "ImageViewer\n" + version, "About ImageViewer", JOptionPane.INFORMATION_MESSAGE);
    }

    private void showStatus(String text)
    {
        statusLabel.setText(text);
    }

    private void makeDarker()
    {
        if (currentImage != null)
        {
            currentImage.darker();
            frame.repaint();
            showStatus("Applied: draker");
        }
        else
        {
            showStatus("No image loaded.");
        }
    }

    private void makeLighter()
    {
        if(currentImage != null)
        {
            currentImage.lighter();
            frame.repaint();
            showStatus("Applied: lighter");
        }
        else
        {
            showStatus("No image loaded");
        }
    }
    private void threshold()
    {
        if(currentImage != null)
        {
            currentImage.threshold();
            frame.repaint();
            showStatus("Applied: threshold");
        }
        else
        {
            showStatus("No image loaded");
        }
    }
}