/*
 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package javax.swing.plaf.basic;

import sun.swing.DefaultLookup;
import sun.swing.UIAction;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.plaf.*;
import javax.swing.border.*;
import java.util.Arrays;
import java.util.ArrayList;


A default L&F implementation of MenuUI.  This implementation
is a "combined" view/controller.
Author:
Georges Saab, David Karlton, Arnaud Weber/**
 * A default L&F implementation of MenuUI.  This implementation
 * is a "combined" view/controller.
 *
 * @author Georges Saab
 * @author David Karlton
 * @author Arnaud Weber
 */
public class BasicMenuUI extends BasicMenuItemUI
{
    
The instance of ChangeListener. /**
     * The instance of {@code ChangeListener}.
     */
    protected ChangeListener         changeListener;

    
The instance of MenuListener. /**
     * The instance of {@code MenuListener}.
     */
    protected MenuListener           menuListener;

    private int lastMnemonic = 0;

    
Uses as the parent of the windowInputMap when selected. /** Uses as the parent of the windowInputMap when selected. */
    private InputMap selectedWindowInputMap;

    /* diagnostic aids -- should be false for production builds. */
    private static final boolean TRACE =   false; // trace creates and disposes
    private static final boolean VERBOSE = false; // show reuse hits/misses
    private static final boolean DEBUG =   false;  // show bad params, misc.

    private static boolean crossMenuMnemonic = true;

    
Constructs a new instance of BasicMenuUI. 
Params:
x – a component
Returns:
a new instance of BasicMenuUI/**
     * Constructs a new instance of {@code BasicMenuUI}.
     *
     * @param x a component
     * @return a new instance of {@code BasicMenuUI}
     */
    public static ComponentUI createUI(JComponent x) {
        return new BasicMenuUI();
    }

    static void loadActionMap(LazyActionMap map) {
        BasicMenuItemUI.loadActionMap(map);
        map.put(new Actions(Actions.SELECT, null, true));
    }


    protected void installDefaults() {
        super.installDefaults();
        updateDefaultBackgroundColor();
        ((JMenu)menuItem).setDelay(200);
        crossMenuMnemonic = UIManager.getBoolean("Menu.crossMenuMnemonic");
    }

    protected String getPropertyPrefix() {
        return "Menu";
    }

    protected void installListeners() {
        super.installListeners();

        if (changeListener == null)
            changeListener = createChangeListener(menuItem);

        if (changeListener != null)
            menuItem.addChangeListener(changeListener);

        if (menuListener == null)
            menuListener = createMenuListener(menuItem);

        if (menuListener != null)
            ((JMenu)menuItem).addMenuListener(menuListener);
    }

    protected void installKeyboardActions() {
        super.installKeyboardActions();
        updateMnemonicBinding();
    }

    void installLazyActionMap() {
        LazyActionMap.installLazyActionMap(menuItem, BasicMenuUI.class,
                                           getPropertyPrefix() + ".actionMap");
    }

    @SuppressWarnings("deprecation")
    void updateMnemonicBinding() {
        int mnemonic = menuItem.getModel().getMnemonic();
        int[] shortcutKeys = (int[])DefaultLookup.get(menuItem, this,
                                                   "Menu.shortcutKeys");
        if (shortcutKeys == null) {
            shortcutKeys = new int[] {KeyEvent.ALT_MASK,
                    KeyEvent.ALT_MASK | KeyEvent.ALT_GRAPH_MASK};
        }
        if (mnemonic == lastMnemonic) {
            return;
        }
        InputMap windowInputMap = SwingUtilities.getUIInputMap(
                       menuItem, JComponent.WHEN_IN_FOCUSED_WINDOW);
        if (lastMnemonic != 0 && windowInputMap != null) {
            for (int shortcutKey : shortcutKeys) {
                windowInputMap.remove(KeyStroke.getKeyStroke
                        (lastMnemonic, shortcutKey, false));
            }
        }
        if (mnemonic != 0) {
            if (windowInputMap == null) {
                windowInputMap = createInputMap(JComponent.
                                              WHEN_IN_FOCUSED_WINDOW);
                SwingUtilities.replaceUIInputMap(menuItem, JComponent.
                                       WHEN_IN_FOCUSED_WINDOW, windowInputMap);
            }
            for (int shortcutKey : shortcutKeys) {
                windowInputMap.put(KeyStroke.getKeyStroke(mnemonic,
                        shortcutKey, false), "selectMenu");
            }
        }
        lastMnemonic = mnemonic;
    }

    protected void uninstallKeyboardActions() {
        super.uninstallKeyboardActions();
        lastMnemonic = 0;
    }

    protected MouseInputListener createMouseInputListener(JComponent c) {
        return getHandler();
    }

    
Returns an instance of MenuListener. 
Params:
c – a component
Returns:
an instance of MenuListener/**
     * Returns an instance of {@code MenuListener}.
     *
     * @param c a component
     * @return an instance of {@code MenuListener}
     */
    protected MenuListener createMenuListener(JComponent c) {
        return null;
    }

    
Returns an instance of ChangeListener. 
Params:
c – a component
Returns:
an instance of ChangeListener/**
     * Returns an instance of {@code ChangeListener}.
     *
     * @param c a component
     * @return an instance of {@code ChangeListener}
     */
    protected ChangeListener createChangeListener(JComponent c) {
        return null;
    }

    protected PropertyChangeListener createPropertyChangeListener(JComponent c) {
        return getHandler();
    }

    BasicMenuItemUI.Handler getHandler() {
        if (handler == null) {
            handler = new Handler();
        }
        return handler;
    }

    protected void uninstallDefaults() {
        menuItem.setArmed(false);
        menuItem.setSelected(false);
        menuItem.resetKeyboardActions();
        super.uninstallDefaults();
    }

    protected void uninstallListeners() {
        super.uninstallListeners();

        if (changeListener != null)
            menuItem.removeChangeListener(changeListener);

        if (menuListener != null)
            ((JMenu)menuItem).removeMenuListener(menuListener);

        changeListener = null;
        menuListener = null;
        handler = null;
    }

    protected MenuDragMouseListener createMenuDragMouseListener(JComponent c) {
        return getHandler();
    }

    protected MenuKeyListener createMenuKeyListener(JComponent c) {
        return (MenuKeyListener)getHandler();
    }

    public Dimension getMinimumSize(JComponent c) {
        return (((JMenu)menuItem).isTopLevelMenu()) ?
            c.getPreferredSize() : null;
    }

    public Dimension getMaximumSize(JComponent c) {
        if (((JMenu)menuItem).isTopLevelMenu()) {
            Dimension d = c.getPreferredSize();
            return new Dimension(d.width, Short.MAX_VALUE);
        }
        return null;
    }

    
Sets timer to the menu. 
Params:
menu – an instance of JMenu./**
     * Sets timer to the {@code menu}.
     *
     * @param menu an instance of {@code JMenu}.
     */
    protected void setupPostTimer(JMenu menu) {
        Timer timer = new Timer(menu.getDelay(), new Actions(
                                    Actions.SELECT, menu,false));
        timer.setRepeats(false);
        timer.start();
    }

    private static void appendPath(MenuElement[] path, MenuElement elem) {
        MenuElement[] newPath = new MenuElement[path.length+1];
        System.arraycopy(path, 0, newPath, 0, path.length);
        newPath[path.length] = elem;
        MenuSelectionManager.defaultManager().setSelectedPath(newPath);
    }

    private static class Actions extends UIAction {
        private static final String SELECT = "selectMenu";

        // NOTE: This will be null if the action is registered in the
        // ActionMap. For the timer use it will be non-null.
        private JMenu menu;
        private boolean force=false;

        Actions(String key, JMenu menu, boolean shouldForce) {
            super(key);
            this.menu = menu;
            this.force = shouldForce;
        }

        private JMenu getMenu(ActionEvent e) {
            if (e.getSource() instanceof JMenu) {
                return (JMenu)e.getSource();
            }
            return menu;
        }

        public void actionPerformed(ActionEvent e) {
            JMenu menu = getMenu(e);
            if (!crossMenuMnemonic) {
                JPopupMenu pm = BasicPopupMenuUI.getLastPopup();
                if (pm != null && pm != menu.getParent()) {
                    return;
                }
            }

            final MenuSelectionManager defaultManager = MenuSelectionManager.defaultManager();
            if(force) {
                Container cnt = menu.getParent();
                if(cnt != null && cnt instanceof JMenuBar) {
                    MenuElement[] me;
                    MenuElement[] subElements;

                    subElements = menu.getPopupMenu().getSubElements();
                    if(subElements.length > 0) {
                        me = new MenuElement[4];
                        me[0] = (MenuElement) cnt;
                        me[1] = menu;
                        me[2] = menu.getPopupMenu();
                        me[3] = subElements[0];
                    } else {
                        me = new MenuElement[3];
                        me[0] = (MenuElement)cnt;
                        me[1] = menu;
                        me[2] = menu.getPopupMenu();
                    }
                    defaultManager.setSelectedPath(me);
                }
            } else {
                MenuElement[] path = defaultManager.getSelectedPath();
                if(path.length > 0 && path[path.length-1] == menu) {
                    appendPath(path, menu.getPopupMenu());
                }
            }
        }

        @Override
        public boolean accept(Object c) {
            if (c instanceof JMenu) {
                return ((JMenu)c).isEnabled();
            }
            return true;
        }
    }

    /*
     * Set the background color depending on whether this is a toplevel menu
     * in a menubar or a submenu of another menu.
     */
    private void updateDefaultBackgroundColor() {
        if (!UIManager.getBoolean("Menu.useMenuBarBackgroundForTopLevel")) {
           return;
        }
        JMenu menu = (JMenu)menuItem;
        if (menu.getBackground() instanceof UIResource) {
            if (menu.isTopLevelMenu()) {
                menu.setBackground(UIManager.getColor("MenuBar.background"));
            } else {
                menu.setBackground(UIManager.getColor(getPropertyPrefix() + ".background"));
            }
        }
    }

    
Instantiated and used by a menu item to handle the current menu selection
from mouse events. A MouseInputHandler processes and forwards all mouse events
to a shared instance of the MenuSelectionManager.

This class is protected so that it can be subclassed by other look and
feels to implement their own mouse handling behavior. All overridden
methods should call the parent methods so that the menu selection
is correct.
See Also:
MenuSelectionManager
Since:
1.4/**
     * Instantiated and used by a menu item to handle the current menu selection
     * from mouse events. A MouseInputHandler processes and forwards all mouse events
     * to a shared instance of the MenuSelectionManager.
     * <p>
     * This class is protected so that it can be subclassed by other look and
     * feels to implement their own mouse handling behavior. All overridden
     * methods should call the parent methods so that the menu selection
     * is correct.
     *
     * @see javax.swing.MenuSelectionManager
     * @since 1.4
     */
    protected class MouseInputHandler implements MouseInputListener {
        // NOTE: This class exists only for backward compatibility. All
        // its functionality has been moved into Handler. If you need to add
        // new functionality add it to the Handler, but make sure this
        // class calls into the Handler.

        public void mouseClicked(MouseEvent e) {
            getHandler().mouseClicked(e);
        }

        
Invoked when the mouse has been clicked on the menu. This
method clears or sets the selection path of the
MenuSelectionManager.
Params:
e – the mouse event/**
         * Invoked when the mouse has been clicked on the menu. This
         * method clears or sets the selection path of the
         * MenuSelectionManager.
         *
         * @param e the mouse event
         */
        public void mousePressed(MouseEvent e) {
            getHandler().mousePressed(e);
        }

        
Invoked when the mouse has been released on the menu. Delegates the
mouse event to the MenuSelectionManager.
Params:
e – the mouse event/**
         * Invoked when the mouse has been released on the menu. Delegates the
         * mouse event to the MenuSelectionManager.
         *
         * @param e the mouse event
         */
        public void mouseReleased(MouseEvent e) {
            getHandler().mouseReleased(e);
        }

        
Invoked when the cursor enters the menu. This method sets the selected
path for the MenuSelectionManager and handles the case
in which a menu item is used to pop up an additional menu, as in a
hierarchical menu system.
Params:
e – the mouse event; not used/**
         * Invoked when the cursor enters the menu. This method sets the selected
         * path for the MenuSelectionManager and handles the case
         * in which a menu item is used to pop up an additional menu, as in a
         * hierarchical menu system.
         *
         * @param e the mouse event; not used
         */
        public void mouseEntered(MouseEvent e) {
            getHandler().mouseEntered(e);
        }
        public void mouseExited(MouseEvent e) {
            getHandler().mouseExited(e);
        }

        
Invoked when a mouse button is pressed on the menu and then dragged.
Delegates the mouse event to the MenuSelectionManager.
Params:
e – the mouse event
See Also:
MouseMotionListener.mouseDragged/**
         * Invoked when a mouse button is pressed on the menu and then dragged.
         * Delegates the mouse event to the MenuSelectionManager.
         *
         * @param e the mouse event
         * @see java.awt.event.MouseMotionListener#mouseDragged
         */
        public void mouseDragged(MouseEvent e) {
            getHandler().mouseDragged(e);
        }

        public void mouseMoved(MouseEvent e) {
            getHandler().mouseMoved(e);
        }
    }

    
As of Java 2 platform 1.4, this previously undocumented class
is now obsolete. KeyBindings are now managed by the popup menu.
/**
     * As of Java 2 platform 1.4, this previously undocumented class
     * is now obsolete. KeyBindings are now managed by the popup menu.
     */
    public class ChangeHandler implements ChangeListener {
        
The instance of JMenu. /**
         * The instance of {@code JMenu}.
         */
        public JMenu    menu;

        
The instance of BasicMenuUI. /**
         * The instance of {@code BasicMenuUI}.
         */
        public BasicMenuUI ui;

        
true if an item of popup menu is selected. /**
         * {@code true} if an item of popup menu is selected.
         */
        public boolean  isSelected = false;

        
The component that was focused.
/**
         * The component that was focused.
         */
        public Component wasFocused;

        
Constructs a new instance of ChangeHandler. 
Params:
m – an instance of JMenu
ui – an instance of BasicMenuUI/**
         * Constructs a new instance of {@code ChangeHandler}.
         *
         * @param m an instance of {@code JMenu}
         * @param ui an instance of {@code BasicMenuUI}
         */
        public ChangeHandler(JMenu m, BasicMenuUI ui) {
            menu = m;
            this.ui = ui;
        }

        public void stateChanged(ChangeEvent e) { }
    }

    private class Handler extends BasicMenuItemUI.Handler implements MenuKeyListener {
        //
        // PropertyChangeListener
        //
        public void propertyChange(PropertyChangeEvent e) {
            if (e.getPropertyName() == AbstractButton.
                             MNEMONIC_CHANGED_PROPERTY) {
                updateMnemonicBinding();
            }
            else {
                if (e.getPropertyName().equals("ancestor")) {
                    updateDefaultBackgroundColor();
                }
                super.propertyChange(e);
            }
        }

        //
        // MouseInputListener
        //
        public void mouseClicked(MouseEvent e) {
        }

        
Invoked when the mouse has been clicked on the menu. This
method clears or sets the selection path of the
MenuSelectionManager.
Params:
e – the mouse event/**
         * Invoked when the mouse has been clicked on the menu. This
         * method clears or sets the selection path of the
         * MenuSelectionManager.
         *
         * @param e the mouse event
         */
        public void mousePressed(MouseEvent e) {
            JMenu menu = (JMenu)menuItem;
            if (!menu.isEnabled())
                return;

            MenuSelectionManager manager =
                MenuSelectionManager.defaultManager();
            if(menu.isTopLevelMenu()) {
                if(menu.isSelected() && menu.getPopupMenu().isShowing()) {
                    manager.clearSelectedPath();
                } else {
                    Container cnt = menu.getParent();
                    if(cnt != null && cnt instanceof JMenuBar) {
                        MenuElement[] me = new MenuElement[2];
                        me[0]=(MenuElement)cnt;
                        me[1]=menu;
                        manager.setSelectedPath(me);
                    }
                }
            }

            MenuElement[] selectedPath = manager.getSelectedPath();
            if (selectedPath.length > 0 &&
                selectedPath[selectedPath.length-1] != menu.getPopupMenu()) {

                if(menu.isTopLevelMenu() ||
                   menu.getDelay() == 0) {
                    appendPath(selectedPath, menu.getPopupMenu());
                } else {
                    setupPostTimer(menu);
                }
            }
        }

        
Invoked when the mouse has been released on the menu. Delegates the
mouse event to the MenuSelectionManager.
Params:
e – the mouse event/**
         * Invoked when the mouse has been released on the menu. Delegates the
         * mouse event to the MenuSelectionManager.
         *
         * @param e the mouse event
         */
        public void mouseReleased(MouseEvent e) {
            JMenu menu = (JMenu)menuItem;
            if (!menu.isEnabled())
                return;
            MenuSelectionManager manager =
                MenuSelectionManager.defaultManager();
            manager.processMouseEvent(e);
            if (!e.isConsumed())
                manager.clearSelectedPath();
        }

        
Invoked when the cursor enters the menu. This method sets the selected
path for the MenuSelectionManager and handles the case
in which a menu item is used to pop up an additional menu, as in a
hierarchical menu system.
Params:
e – the mouse event; not used/**
         * Invoked when the cursor enters the menu. This method sets the selected
         * path for the MenuSelectionManager and handles the case
         * in which a menu item is used to pop up an additional menu, as in a
         * hierarchical menu system.
         *
         * @param e the mouse event; not used
         */
        public void mouseEntered(MouseEvent e) {
            JMenu menu = (JMenu)menuItem;
            // only disable the menu highlighting if it's disabled and the property isn't
            // true. This allows disabled rollovers to work in WinL&F
            if (!menu.isEnabled() && !UIManager.getBoolean("MenuItem.disabledAreNavigable")) {
                return;
            }

            MenuSelectionManager manager =
                MenuSelectionManager.defaultManager();
            MenuElement[] selectedPath = manager.getSelectedPath();
            if (!menu.isTopLevelMenu()) {
                if(!(selectedPath.length > 0 &&
                     selectedPath[selectedPath.length-1] ==
                     menu.getPopupMenu())) {
                    if(menu.getDelay() == 0) {
                        appendPath(getPath(), menu.getPopupMenu());
                    } else {
                        manager.setSelectedPath(getPath());
                        setupPostTimer(menu);
                    }
                }
            } else {
                if(selectedPath.length > 0 &&
                   selectedPath[0] == menu.getParent()) {
                    MenuElement[] newPath = new MenuElement[3];
                    // A top level menu's parent is by definition
                    // a JMenuBar
                    newPath[0] = (MenuElement)menu.getParent();
                    newPath[1] = menu;
                    if (BasicPopupMenuUI.getLastPopup() != null) {
                        newPath[2] = menu.getPopupMenu();
                    }
                    manager.setSelectedPath(newPath);
                }
            }
        }
        public void mouseExited(MouseEvent e) {
        }

        
Invoked when a mouse button is pressed on the menu and then dragged.
Delegates the mouse event to the MenuSelectionManager.
Params:
e – the mouse event
See Also:
MouseMotionListener.mouseDragged/**
         * Invoked when a mouse button is pressed on the menu and then dragged.
         * Delegates the mouse event to the MenuSelectionManager.
         *
         * @param e the mouse event
         * @see java.awt.event.MouseMotionListener#mouseDragged
         */
        public void mouseDragged(MouseEvent e) {
            JMenu menu = (JMenu)menuItem;
            if (!menu.isEnabled())
                return;
            MenuSelectionManager.defaultManager().processMouseEvent(e);
        }
        public void mouseMoved(MouseEvent e) {
        }


        //
        // MenuDragHandler
        //
        public void menuDragMouseEntered(MenuDragMouseEvent e) {}
        public void menuDragMouseDragged(MenuDragMouseEvent e) {
            if (menuItem.isEnabled() == false)
                return;

            MenuSelectionManager manager = e.getMenuSelectionManager();
            MenuElement[] path = e.getPath();

            Point p = e.getPoint();
            if(p.x >= 0 && p.x < menuItem.getWidth() &&
               p.y >= 0 && p.y < menuItem.getHeight()) {
                JMenu menu = (JMenu)menuItem;
                MenuElement[] selectedPath = manager.getSelectedPath();
                if(!(selectedPath.length > 0 &&
                     selectedPath[selectedPath.length-1] ==
                     menu.getPopupMenu())) {
                    if(menu.isTopLevelMenu() ||
                       menu.getDelay() == 0  ||
                       e.getID() == MouseEvent.MOUSE_DRAGGED) {
                        appendPath(path, menu.getPopupMenu());
                    } else {
                        manager.setSelectedPath(path);
                        setupPostTimer(menu);
                    }
                }
            } else if(e.getID() == MouseEvent.MOUSE_RELEASED) {
                Component comp = manager.componentForPoint(e.getComponent(), e.getPoint());
                if (comp == null)
                    manager.clearSelectedPath();
            }

        }
        public void menuDragMouseExited(MenuDragMouseEvent e) {}
        public void menuDragMouseReleased(MenuDragMouseEvent e) {}

        //
        // MenuKeyListener
        //
        
Open the Menu
/**
         * Open the Menu
         */
        public void menuKeyTyped(MenuKeyEvent e) {
            if (!crossMenuMnemonic && BasicPopupMenuUI.getLastPopup() != null) {
                // when crossMenuMnemonic is not set, we don't open a toplevel
                // menu if another toplevel menu is already open
                return;
            }

            if (BasicPopupMenuUI.getPopups().size() != 0) {
                //Fix 6939261: to return in case not on the main menu
                //and has a pop-up.
                //after return code will be handled in BasicPopupMenuUI.java
                return;
            }

            char key = Character.toLowerCase((char)menuItem.getMnemonic());
            MenuElement[] path = e.getPath();
            if (key == Character.toLowerCase(e.getKeyChar())) {
                JPopupMenu popupMenu = ((JMenu)menuItem).getPopupMenu();
                ArrayList<MenuElement> newList = new ArrayList<>(Arrays.asList(path));
                newList.add(popupMenu);
                MenuElement[] subs = popupMenu.getSubElements();
                MenuElement sub =
                        BasicPopupMenuUI.findEnabledChild(subs, -1, true);
                if(sub != null) {
                    newList.add(sub);
                }
                MenuSelectionManager manager = e.getMenuSelectionManager();
                MenuElement[] newPath = new MenuElement[0];;
                newPath = newList.toArray(newPath);
                manager.setSelectedPath(newPath);
                e.consume();
            }
        }

        public void menuKeyPressed(MenuKeyEvent e) {}
        public void menuKeyReleased(MenuKeyEvent e) {}
    }
}