package edu.princeton.toy;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;
import javax.swing.event.*;

import edu.princeton.swing.*;
import edu.princeton.swing.text.*;

public class TExampleDialog extends JDialog implements ActionListener, ListSelectionListener
{
    /**
     * The number of rows titles which will be shown by the title selection.
     */
    public static final int TITLE_ROWS = 7;

    /**
     * The maximum number of rows of the text which will be shown by the description.
     */
    public static final int DESCRIPTION_ROWS = 7;

    private static final String CLASS_STRING = TExampleDialog.class.toString();

    public static final String       OPEN_COMMAND = CLASS_STRING + "#openCommand";
    public static final String     CANCEL_COMMAND = CLASS_STRING + "#cancelCommand";

    public static final String     UPDATE_COMMAND = CLASS_STRING + "#updateCommand";

    private String selection[];
    private int lastSelectedIndex;

    private PHighlightedTextArea textArea;
    private PWrappedList list;
    private TProgramDocument program;
    private JButton openButton;

    /**
     * Creates a new TExampleDialog, centered in the screen.
     */
    private TExampleDialog(Frame parent)
    {
        super(parent, "Open Example Program", true);
    }

    /**
     * Creates a new TExampleDialog, centered in the screen.
     */
    private TExampleDialog(Dialog parent)
    {
        super(parent, "Open Example Program", true);
    }

    /**
     * Called by the constructors to init the JDialog properly.
     */
    protected void dialogInit()
    {
        super.dialogInit();

        // Prepare the menu
        JMenuBar menuBar;
        JMenu menu;
        JMenuItem menuItem;

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

        {
            // Build the edit menu
            menu = new JMenu("Edit");
            menu.setMnemonic(KeyEvent.VK_E);
            menuBar.add(menu);

            menu.add(ClipboardTargetManager.CUT_ACTION.createMenuItem());
            menu.add(ClipboardTargetManager.COPY_ACTION.createMenuItem());
            menu.add(ClipboardTargetManager.PASTE_ACTION.createMenuItem());
            menu.addSeparator();
            menu.add(ClipboardTargetManager.SELECT_ALL_ACTION.createMenuItem());
        }

        // Build the dialog's contents
        Container contentPane = getContentPane();
        contentPane.setLayout(new GridBagLayout());

        // Add the examples label
        contentPane.add(
            new JLabel("Available Examples:", SwingConstants.LEFT),
            new GridBagConstraints(
                0, 0, 2, 1,
                0.0, 0.0,
                GridBagConstraints.NORTHWEST,
                GridBagConstraints.BOTH,
                new Insets(2, 2, 2, 2),
                0, 0
                )
            );

        {
            // Prepare the example list
            String exampleTitles[] = new String[TExampleManager.getExampleCount()];
            for (int ctr = 0; ctr < exampleTitles.length; ctr++)
                exampleTitles[ctr] = TExampleManager.getExampleTitle(ctr);

            list = new PWrappedList(exampleTitles);
            list.addActionListener(this);
            list.setActionCommand(OPEN_COMMAND);
            list.setVisibleRowCount(TITLE_ROWS);
            list.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
            list.addListSelectionListener(this);

            contentPane.add(
                new JScrollPane(
                    list,
                    JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                    JScrollPane.HORIZONTAL_SCROLLBAR_NEVER
                    ),
                new GridBagConstraints(
                    0, 1, 2, 1,
                    0.0, 1.0,
                    GridBagConstraints.NORTHWEST,
                    GridBagConstraints.BOTH,
                    new Insets(2, 2, 2, 2),
                    0, 0
                    )
                );
        }

        // Add the preview label
        contentPane.add(
            new JLabel("Preview:", SwingConstants.LEFT),
            new GridBagConstraints(
                0, 2, 2, 1,
                0.0, 0.0,
                GridBagConstraints.NORTHWEST,
                GridBagConstraints.BOTH,
                new Insets(2, 2, 2, 2),
                0, 0
                )
            );

        {
            // Prepare the Example preview area
            program = new TProgramDocument("");
            textArea = new PHighlightedTextArea(
                program,
                DESCRIPTION_ROWS,
                TProgramDocument.OUTSIDE_MARGIN_COLUMN + 2
                );
            textArea.setEditable(false);
            textArea.setHighlightedLine(PHighlightedTextArea.NEVER_HIGHLIGHT);

            TOptionsFrame.registerComponent(textArea, TOptionsFrame.PROGRAM_AREA_INDEX);
            TOptionsFrame.registerHighlightedTextArea(textArea);

            int columnMarkers[] = new int[3];
            columnMarkers[0] = 8;
            columnMarkers[1] = TProgramDocument.COMMENT_COLUMN;
            columnMarkers[2] = TProgramDocument.OUTSIDE_MARGIN_COLUMN;
            textArea.setColumnMarkers(columnMarkers);

            contentPane.add(
                textArea,
                new GridBagConstraints(
                    0, 3, 2, 1,
                    0.0, 0.1,
                    GridBagConstraints.NORTHWEST,
                    GridBagConstraints.BOTH,
                    new Insets(2, 2, 2, 2),
                    0, 0
                    )
                );
        }

        // Add the spacer to the left of the button panel
        contentPane.add(
            new PSpacer(1, 1),
            new GridBagConstraints(
                0, 4, 1, 1,
                1.0, 0.0,
                GridBagConstraints.NORTHWEST,
                GridBagConstraints.BOTH,
                new Insets(2, 2, 2, 2),
                0, 0
                )
            );

        {
            // Prepare the button panel
            JPanel buttonPanel = new JPanel(new GridLayout(1, 2, 4, 0));

            JButton button = new JButton("Open");
            button.addActionListener(this);
            button.setActionCommand(OPEN_COMMAND);
            openButton = button;
            buttonPanel.add(button);

            button = new JButton("Cancel");
            button.addActionListener(this);
            button.setActionCommand(CANCEL_COMMAND);
            buttonPanel.add(button);

            contentPane.add(
                buttonPanel,
                new GridBagConstraints(
                    1, 4, 1, 1,
                    0.0, 0.0,
                    GridBagConstraints.NORTHWEST,
                    GridBagConstraints.BOTH,
                    new Insets(2, 2, 2, 2),
                    0, 0
                    )
                );
        }

        doCommand(UPDATE_COMMAND, null);

        setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
        setResizable(false);

        pack();
        Window owner = getOwner();
        setLocation(
            owner.getX() + owner.getWidth()  / 2 - getWidth()  / 2,
            owner.getY() + owner.getHeight() / 2 - getHeight() / 2
            );

        lastSelectedIndex = -1;
        selection = null;
    }

    /**
     * Override dispose() to also unregister the program text area.
     */
    public void dispose()
    {
        TOptionsFrame.unregisterComponent(textArea, TOptionsFrame.PROGRAM_AREA_INDEX);
        TOptionsFrame.registerHighlightedTextArea(textArea);
        super.dispose();
    }

    /**
     * Shows a TExampleDialog and returns the text of the selected examples.
     *
     * @param The parent of the dialog.  This must be an instance of java.awt.Frame or
     * java.awt.Dialog.
     * @return An array containing the text of the selected examples, null if nothing was selected.
     */
    public static String[] showExampleDialog(Window parent)
    {
        if (parent == null)
            throw new NullPointerException();

        TExampleDialog dialog;
        if (parent instanceof Frame)
            dialog = new TExampleDialog((Frame)parent);
        else
            dialog = new TExampleDialog((Dialog)parent);

        dialog.setVisible(true);

        String selection[] = dialog.selection;
        dialog.dispose();

        return selection;
    }

    /**
     * Performs a command based on the argument.
     *
     * @param command An object representing the command.  Note that pointer equality (not string
     * equality) is tested here, so it is important to use the string constants defined in this
     * class.  An IllegalArgumentException will be thrown if the argument is invalid.
     * @param extraInfo Any extra information necessary.
     * @return True iff the command was executed sucessfully.
     */
    public boolean doCommand(String command, Object extraInfo)
    {
        ////////////////////////////////////////////////////////////////////////////////////////////
        if (command == OPEN_COMMAND)
        {
            int selectedIndices[] = list.getSelectedIndices();
            int length = selectedIndices.length;

            selection = new String[length];

            for (int ctr = 0; ctr < length; ctr++)
                selection[ctr] = TExampleManager.getExampleText(selectedIndices[ctr]);

            setVisible(false);
            return true;
        }
        ////////////////////////////////////////////////////////////////////////////////////////////
        if (command == CANCEL_COMMAND)
        {
            selection = null;

            setVisible(false);
            return true;
        }


        ////////////////////////////////////////////////////////////////////////////////////////////
        if (command == UPDATE_COMMAND)
        {
            int selectedIndex = list.getSelectedIndex();

            if (selectedIndex != lastSelectedIndex)
            {
                if (selectedIndex == -1)
                {
                    program.setText("");
                    openButton.setEnabled(false);
                    lastSelectedIndex = selectedIndex;
                }
                else {
                    program.setText(TExampleManager.getExampleText(selectedIndex));
                    openButton.setEnabled(true);
                    lastSelectedIndex = selectedIndex;
                }
            }

            return true;
        }

        throw new IllegalArgumentException();
    }

    /**
     * Implement ActionListener to pass the command onto doCommand().
     *
     * @see #doCommand(String, Object)
     */
    public void actionPerformed(ActionEvent e)
    {
        doCommand(e.getActionCommand(), null);
    }

    /**
     * Implement ListSelectionListener to pass an update command onto doCommand().
     *
     * @see #doCommand(String, Object)
     */
    public void valueChanged(ListSelectionEvent e)
    {
        doCommand(UPDATE_COMMAND, null);
    }
}