package edu.hws.eck.mdb;

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

/**
 * This class defines a custom dialog box that asks the user to enter
 * a new size for the Mandelbrot image.  The dialog box has two input
 * boxes where the user can enter integers.
 */
public class SetImageSizeDialog extends JDialog {

    /**
     * This static convenience method will show a dialog of type
     * SetImageSizeDialog.  It will not return until the user dismisses
     * the dialog, by clicking "OK" or "Cancel" or by clicking the
     * dialog's close box.  The user is forced to either enter legal
     * inputs or to cancel the dialog.  Legal input values are integers
     * in the range 10 to 5000.  NOTE:  If you use this method, you
     * don't have to worry about anything else in the class.
     * @param frame The "parent" of the dialog box.  This frame is "blocked"
     *   until the user closed the dialog box.
     * @param oldSize If non-null, then the values of oldSize.width and
     *    oldSize.height are put in the input boxes.  If null, the initial
     *    values in the input boxes are set to 800 and 600.
     * @return null, if the user cancels the dialog or clicks OK without changing
     *    the values in the input boxes; if the user changes the values and clicks
     *    OK, then the return value is a Dimension object whose width
     *    and height give the user's inputs.
     */
    static Dimension showDialog(JFrame frame, Dimension oldSize) {
        SetImageSizeDialog dialog = new SetImageSizeDialog(frame,oldSize);
        dialog.setVisible(true);  // does not return until the dialog box is dismissed
        Dimension newSize = dialog.getInputSize();
        if (newSize == null || newSize.equals(oldSize))
            return null;
        return newSize;
    }
    
    private Dimension inputSize;  // This will be set to the user's input,
                                  // when the user clicks OK and the input
                                  // is legal.

    private JButton cancelButton;
    private JButton okButton;
    private JTextField widthInput;
    private JTextField heightInput;
    
    
    /**
     * This constructor creates the dialog's user interface and sets up
     * listeners to detect clicks on the buttons or on the dialog box's
     * close box.  When the user clicks OK, the input boxes are checked.
     * If the input is legal, the dialog box is closed; if not, an error
     * message is displayed and the dialog stays up.  Note that this constructor
     * does not make the dialog box visible.  Note also that the dialog box
     * is set to DISPOSE itself when it is closed and so cannot be reused.
     * (For a reusable dialog, it should be "hidden" rather than disposed.)
     * @param frame the parent of this dialog box, which is blocked until
     *    the dialog box is closed.
     * @param oldSize initial values for the input box
     */
    public SetImageSizeDialog(JFrame frame, Dimension oldSize) {
        super(frame,I18n.tr("imagesizedialog.title"),true); 
                // The "true" makes this a modal dialog that blocks its parent frame.
        JPanel content = new JPanel();
        content.setLayout(new BorderLayout(10,10));
        setContentPane(content);
        content.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
        if (oldSize == null)
            oldSize = new Dimension(800,600);
        widthInput = new JTextField(""+oldSize.width, 4);
        heightInput = new JTextField(""+oldSize.height, 4);
        JPanel input = new JPanel();
        input.add(Box.createHorizontalStrut(10));
        input.add(new JLabel(I18n.tr("imagesizedialog.widthequals")));
        input.add(widthInput);
        input.add(Box.createHorizontalStrut(10));
        input.add(new JLabel(I18n.tr("imagesizedialog.heightequals")));
        input.add(heightInput);
        cancelButton = new JButton(I18n.tr("button.cancel"));
        okButton = new JButton(I18n.tr("button.ok"));
        getRootPane().setDefaultButton(okButton);  // This means that the OK button can be invoked by pressing return.
        JPanel buttons = new JPanel();
        buttons.add(cancelButton);
        buttons.add(okButton);
        content.add( new JLabel(I18n.tr("imagesizedialog.question")), BorderLayout.NORTH );  // Message to user.
        content.add( input, BorderLayout.CENTER );
        content.add( buttons, BorderLayout.SOUTH );
        setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE); // Close window when user clicks its close box.
        pack();
        setLocation(frame.getX()+50, frame.getY()+75); // Position near top left of frame.
        Dimension screensize = Toolkit.getDefaultToolkit().getScreenSize();
        int x = getX();  // The next six lines ensure that the dialog box is actually on the screen!
        int y = getY();
        if (x + getWidth() > screensize.width)
            x = screensize.width - getWidth() - 30;  // Move left to bring dialog onto screen.
        if (y + getHeight() > screensize.height)
            y = screensize.height - getHeight() - 30;  // Move up to bring dialog onto screen.
        setLocation(x,y);
        cancelButton.addActionListener( new ActionListener() {
               // When the user clicks Cancel, dispose the window.
            public void actionPerformed(ActionEvent evt) {
                dispose();
            }
        });
        okButton.addActionListener( new ActionListener() {
               // When the user clicks OK, check the input; close the window only if the input is legal.
            public void actionPerformed(ActionEvent evt) {
                if (checkInput())
                    dispose();
            }
        });
    }
    
    /**
     * After the dialog box has closed, this can be called to get
     * the user's response.
     * @return null, if dialog was canceled, or the width/height
     *   entered by the user if not.
     */
    public Dimension getInputSize() {
        return inputSize;
    }
    
    /**
     * This method is called when the user clicks OK.  It gets the
     * user's input and checks whether it is legal
     * @return true if the input is legal, false if not.
     */
    private boolean checkInput() {
        inputSize = null;
        int width, height;
        try {
            width = Integer.parseInt(widthInput.getText());
        }
        catch (NumberFormatException e) {
            JOptionPane.showMessageDialog(this,
                    I18n.tr("imagesizedialog.error.widthnotanumber", widthInput.getText()));
            widthInput.selectAll();
            widthInput.requestFocus();
            return false;
        }
        try {
            height = Integer.parseInt(heightInput.getText());
        }
        catch (NumberFormatException e) {
            JOptionPane.showMessageDialog(this,
                    I18n.tr("imagesizedialog.error.heightnotanumber", heightInput.getText())); 
            heightInput.selectAll();
            heightInput.requestFocus();
            return false;
        }
        if (width < 10 || width > 5000) {
            JOptionPane.showMessageDialog(this,
                    I18n.tr("imagesizedialog.error.badwidth", ""+width)); 
            widthInput.selectAll();
            widthInput.requestFocus();
            return false;
        }
        else if (height < 10 || height > 5000) {
            JOptionPane.showMessageDialog(this,
                    I18n.tr("imagesizedialog.error.badheight", ""+width)); 
            heightInput.selectAll();
            heightInput.requestFocus();
            return false;
        }
        inputSize = new Dimension(width,height);
        return true;
    }
    

}
