/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.action;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MenuAdapter;
import org.eclipse.swt.events.MenuEvent;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.CoolBar;
import org.eclipse.swt.widgets.Decorations;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.ToolBar;

/**
 * A menu manager is a contribution manager which realizes itself and its items
 * in a menu control; either as a menu bar, a sub-menu, or a context menu.
 * <p>
 * This class may be instantiated; it may also be subclassed.
 * </p>
 */
public class MenuManager extends ContributionManager implements IMenuManager {

    /**
     * The menu id.
     */
    private String id;

    /**
     * List of registered menu listeners (element type: <code>IMenuListener</code>).
     */
    private ListenerList listeners = new ListenerList();

    /**
     * The menu control; <code>null</code> before
     * creation and after disposal.
     */
    private Menu menu = null;

    /**
     * The menu item widget; <code>null</code> before
     * creation and after disposal. This field is used
     * when this menu manager is a sub-menu.
     */
    private MenuItem menuItem;

    /**
     * The text for a sub-menu.
     */
    private String menuText;

    /**
     * The overrides for items of this manager
     */
    private IContributionManagerOverrides overrides;

    /**
     * The parent contribution manager.
     */
    private IContributionManager parent;

    /**
     * Indicates whether <code>removeAll</code> should be
     * called just before the menu is displayed.
     */
    private boolean removeAllWhenShown = false;

    /**
     * Indicates this item is visible in its manager; <code>true</code> 
     * by default.
     */
    private boolean visible = true;

    /**
     * Creates a menu manager.  The text and id are <code>null</code>.
     * Typically used for creating a context menu, where it doesn't need to be referred to by id.
     */
    public MenuManager() {
        this(null, null);
    }

    /**
     * Creates a menu manager with the given text. The id of the menu
     * is <code>null</code>.
     * Typically used for creating a sub-menu, where it doesn't need to be referred to by id.
     *
     * @param text the text for the menu, or <code>null</code> if none
     */
    public MenuManager(String text) {
        this(text, null);
    }

    /**
     * Creates a menu manager with the given text and id.
     * Typically used for creating a sub-menu, where it needs to be referred to by id.
     *
     * @param text the text for the menu, or <code>null</code> if none
     * @param id the menu id, or <code>null</code> if it is to have no id
     */
    public MenuManager(String text, String id) {
        this.menuText = text;
        this.id = id;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#addMenuListener(org.eclipse.jface.action.IMenuListener)
     */
    public void addMenuListener(IMenuListener listener) {
        listeners.add(listener);
    }

    /**
     * Creates and returns an SWT context menu control for this menu,
     * and installs all registered contributions.
     * Does not create a new control if one already exists.
     * <p>
     * Note that the menu is not expected to be dynamic.
     * </p>
     *
     * @param parent the parent control
     * @return the menu control
     */
    public Menu createContextMenu(Control parent) {
        if (!menuExist()) {
            menu = new Menu(parent);
            initializeMenu();
        }
        return menu;
    }

    /**
     * Creates and returns an SWT menu bar control for this menu,
     * for use in the given <code>Decorations</code>, and installs all registered
     * contributions. Does not create a new control if one already exists.
     *
     * @param parent the parent decorations
     * @return the menu control
     * @since 2.1
     */
    public Menu createMenuBar(Decorations parent) {
        if (!menuExist()) {
            menu = new Menu(parent, SWT.BAR);
            update(false);
        }
        return menu;
    }

    /**
     * Creates and returns an SWT menu bar control for this menu, for use in the
     * given <code>Shell</code>, and installs all registered contributions. Does not
     * create a new control if one already exists. This implementation simply calls
     * the <code>createMenuBar(Decorations)</code> method
     *
     * @param parent the parent decorations
     * @return the menu control
     * @deprecated use <code>createMenuBar(Decorations)</code> instead.
     */
    public Menu createMenuBar(Shell parent) {
        return createMenuBar((Decorations) parent);
    }

    /**
     * Disposes of this menu manager and frees all allocated SWT resources.
     * Notifies all contribution items of the dispose. Note that this method does
     * not clean up references between this menu manager and its associated
     * contribution items. Use <code>removeAll</code> for that purpose.
     */
    public void dispose() {
        if (menuExist())
            menu.dispose();
        menu = null;

        if (menuItem != null) {
            menuItem.dispose();
            menuItem = null;
        }

        IContributionItem[] items = getItems();
        for (int i = 0; i < items.length; i++) {
            items[i].dispose();
        }
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#fill(org.eclipse.swt.widgets.Composite)
     */
    public void fill(Composite parent) {
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#fill(org.eclipse.swt.widgets.CoolBar, int)
     */
    public void fill(CoolBar parent, int index) {
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#fill(org.eclipse.swt.widgets.Menu, int)
     */
    public void fill(Menu parent, int index) {
        if (menuItem == null || menuItem.isDisposed()) {
            if (index >= 0)
                menuItem = new MenuItem(parent, SWT.CASCADE, index);
            else
                menuItem = new MenuItem(parent, SWT.CASCADE);

            menuItem.setText(getMenuText());

            if (!menuExist())
                menu = new Menu(parent);

            menuItem.setMenu(menu);

            initializeMenu();

            // populate the submenu, in order to enable accelerators
            // and to set enabled state on the menuItem properly
            update(true);
        }
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#fill(org.eclipse.swt.widgets.ToolBar, int)
     */
    public void fill(ToolBar parent, int index) {
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#findMenuUsingPath(java.lang.String)
     */
    public IMenuManager findMenuUsingPath(String path) {
        IContributionItem item = findUsingPath(path);
        if (item instanceof IMenuManager)
            return (IMenuManager) item;
        return null;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#findUsingPath(java.lang.String)
     */
    public IContributionItem findUsingPath(String path) {
        String id = path;
        String rest = null;
        int separator = path.indexOf('/');
        if (separator != -1) {
            id = path.substring(0, separator);
            rest = path.substring(separator + 1);
        } else {
            return super.find(path);
        }

        IContributionItem item = super.find(id);
        if (item instanceof IMenuManager) {
            IMenuManager manager = (IMenuManager) item;
            return manager.findUsingPath(rest);
        }
        return null;
    }

    /**
     * Notifies any menu listeners that a menu is about to show.
     * Only listeners registered at the time this method is called are notified.
     *
     * @param manager the menu manager
     *
     * @see IMenuListener#menuAboutToShow
     */
    private void fireAboutToShow(IMenuManager manager) {
        Object[] listeners = this.listeners.getListeners();
        for (int i = 0; i < listeners.length; ++i) {
            ((IMenuListener) listeners[i]).menuAboutToShow(manager);
        }
    }

    /**
     * Notifies any menu listeners that a menu is about to hide.
     * Only listeners registered at the time this method is called are notified.
     *
     * @param manager the menu manager
     *
     * @see IMenuListener#menuAboutToHide
     */
    private void fireAboutToHide(IMenuManager manager) {
        final Object[] listeners = this.listeners.getListeners();
        for (int i = 0; i < listeners.length; ++i) {
        	final Object listener = listeners[i];
			if (listener instanceof IMenuListener2) {
				final IMenuListener2 listener2 = (IMenuListener2) listener;
				listener2.menuAboutToHide(manager);
			}
        }
    }

    /**
	 * Returns the menu id. The menu id is used when creating a contribution
	 * item for adding this menu as a sub menu of another.
	 * 
	 * @return the menu id
	 */
    public String getId() {
        return id;
    }

    /**
     * Returns the SWT menu control for this menu manager.
     *
     * @return the menu control
     */
    public Menu getMenu() {
        return menu;
    }

    /**
     * Returns the text shown in the menu.
     *
     * @return the menu text
     */
    public String getMenuText() {
        return menuText;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionManager#getOverrides()
     */
    public IContributionManagerOverrides getOverrides() {
        if (overrides == null) {
            if (parent == null) {
                overrides = new IContributionManagerOverrides() {
                    public Integer getAccelerator(IContributionItem item) {
                        return null;
                    }

                    public String getAcceleratorText(IContributionItem item) {
                        return null;
                    }

                    public Boolean getEnabled(IContributionItem item) {
                        return null;
                    }

                    public String getText(IContributionItem item) {
                        return null;
                    }
                };
            } else {
                overrides = parent.getOverrides();
            }
            super.setOverrides(overrides);
        }
        return overrides;
    }

    /**
     * Returns the parent contribution manager of this manger.
     * 
     * @return the parent contribution manager
     * @since 2.0
     */
    public IContributionManager getParent() {
        return parent;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#getRemoveAllWhenShown()
     */
    public boolean getRemoveAllWhenShown() {
        return removeAllWhenShown;
    }

    /**
     * Notifies all listeners that this menu is about to appear.
     */
    private void handleAboutToShow() {
        if (removeAllWhenShown)
            removeAll();
        fireAboutToShow(this);
        update(false, true);
    }

    /**
     * Notifies all listeners that this menu is about to disappear.
     */
    private void handleAboutToHide() {
        fireAboutToHide(this);
    }

    /**
     * Initializes the menu control.
     */
    private void initializeMenu() {
        menu.addMenuListener(new MenuAdapter() {
            public void menuHidden(MenuEvent e) {
                //			ApplicationWindow.resetDescription(e.widget);
            	handleAboutToHide();
            }

            public void menuShown(MenuEvent e) {
                handleAboutToShow();
            }
        });
        // Don't do an update(true) here, in case menu is never opened.
        // Always do it lazily in handleAboutToShow().
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#isDynamic()
     */
    public boolean isDynamic() {
        return false;
    }

    /**
     * Returns whether this menu should be enabled or not.
     * Used to enable the menu item containing this menu when it is realized as a sub-menu.
     * <p>
     * The default implementation of this framework method
     * returns <code>true</code>. Subclasses may reimplement.
     * </p>
     *
     * @return <code>true</code> if enabled, and
     *   <code>false</code> if disabled
     */
    public boolean isEnabled() {
        return true;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#isGroupMarker()
     */
    public boolean isGroupMarker() {
        return false;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#isSeparator()
     */
    public boolean isSeparator() {
        return false;
    }

    /**
     * @deprecated this method is no longer a part of the 
     *   {@link org.eclipse.jface.action.IContributionItem} API.
     */
    public boolean isSubstituteFor(IContributionItem item) {
        return this.equals(item);
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#isVisible()
     */
    public boolean isVisible() {
        if (!visible)
            return false; // short circut calculations in this case

        // menus arent visible if all of its children are invisible (or only contains visible separators).
        IContributionItem[] childItems = getItems();
        boolean visibleChildren = false;
        for (int j = 0; j < childItems.length; j++) {
            if (childItems[j].isVisible() && !childItems[j].isSeparator()) {
                visibleChildren = true;
                break;
            }
        }

        return visibleChildren;
    }

    
    /**
     * The <code>MenuManager</code> implementation of this <code>ContributionManager</code> method
     * also propagates the dirty flag up the parent chain.
     * 
     * @since 3.1
     */
    public void markDirty() {
        super.markDirty();
        // Can't optimize by short-circuiting when the first dirty manager is encountered,
        // since non-visible children are not even processed.
        // That is, it's possible to have a dirty sub-menu under a non-dirty parent menu
        // even after the parent menu has been updated. 
        // If items are added/removed in the sub-menu, we still need to propagate the dirty flag up,
        // even if the sub-menu is already dirty, since the result of isVisible() may change
        // due to the added/removed items.
        IContributionManager parent = getParent();
        if (parent != null) {
            parent.markDirty();
        }
    }
    
    /**
     * Returns whether the menu control is created
     * and not disposed.
     * 
     * @return <code>true</code> if the control is created
     *	and not disposed, <code>false</code> otherwise
     */
    private boolean menuExist() {
        return menu != null && !menu.isDisposed();
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#removeMenuListener(org.eclipse.jface.action.IMenuListener)
     */
    public void removeMenuListener(IMenuListener listener) {
        listeners.remove(listener);
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#saveWidgetState()
     */
    public void saveWidgetState() {
    }

    /**
     * Sets the overrides for this contribution manager
     * 
     * @param newOverrides the overrides for the items of this manager
     * @since 2.0
     */
    public void setOverrides(IContributionManagerOverrides newOverrides) {
        overrides = newOverrides;
        super.setOverrides(overrides);
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#setParent(org.eclipse.jface.action.IContributionManager)
     */
    public void setParent(IContributionManager manager) {
        parent = manager;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#setRemoveAllWhenShown(boolean)
     */
    public void setRemoveAllWhenShown(boolean removeAll) {
        this.removeAllWhenShown = removeAll;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#setVisible(boolean)
     */
    public void setVisible(boolean visible) {
        this.visible = visible;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#update()
     */
    public void update() {
        updateMenuItem();
    }

    /**
     * The <code>MenuManager</code> implementation of this <code>IContributionManager</code>
     * updates this menu, but not any of its submenus.
     *
     * @see #updateAll
     */
    public void update(boolean force) {
        update(force, false);
    }

    /**
     * Incrementally builds the menu from the contribution items.
     * This method leaves out double separators and separators in the first 
     * or last position.
     *
     * @param force <code>true</code> means update even if not dirty,
     *   and <code>false</code> for normal incremental updating
     * @param recursive <code>true</code> means recursively update 
     *   all submenus, and <code>false</code> means just this menu
     */
    protected void update(boolean force, boolean recursive) {
        if (isDirty() || force) {
            if (menuExist()) {
                // clean contains all active items without double separators
                IContributionItem[] items = getItems();
                List clean = new ArrayList(items.length);
                IContributionItem separator = null;
                for (int i = 0; i < items.length; ++i) {
                    IContributionItem ci = items[i];
                    if (!ci.isVisible())
                        continue;
                    if (ci.isSeparator()) {
                        // delay creation until necessary 
                        // (handles both adjacent separators, and separator at end)
                        separator = ci;
                    } else {
                        if (separator != null) {
                            if (clean.size() > 0) // no separator if first item
                                clean.add(separator);
                            separator = null;
                        }
                        clean.add(ci);
                    }
                }

                // remove obsolete (removed or non active)
                MenuItem[] mi = menu.getItems();

                for (int i = 0; i < mi.length; i++) {
                    Object data = mi[i].getData();

                    if (data == null || !clean.contains(data)) {
                        mi[i].dispose();
                    } else if (data instanceof IContributionItem
                            && ((IContributionItem) data).isDynamic()
                            && ((IContributionItem) data).isDirty()) {
                        mi[i].dispose();
                    }
                }

                // add new
                mi = menu.getItems();
                int srcIx = 0;
                int destIx = 0;

                for (Iterator e = clean.iterator(); e.hasNext();) {
                    IContributionItem src = (IContributionItem) e.next();
                    IContributionItem dest;

                    // get corresponding item in SWT widget
                    if (srcIx < mi.length)
                        dest = (IContributionItem) mi[srcIx].getData();
                    else
                        dest = null;

                    if (dest != null && src.equals(dest)) {
                        srcIx++;
                        destIx++;
                    } else if (dest != null && dest.isSeparator()
                            && src.isSeparator()) {
                        mi[srcIx].setData(src);
                        srcIx++;
                        destIx++;
                    } else {
                        int start = menu.getItemCount();
                        src.fill(menu, destIx);
                        int newItems = menu.getItemCount() - start;
                        for (int i = 0; i < newItems; i++) {
                            MenuItem item = menu.getItem(destIx++);
                            item.setData(src);
                        }
                    }

                    // May be we can optimize this call. If the menu has just
                    // been created via the call src.fill(fMenuBar, destIx) then
                    // the menu has already been updated with update(true) 
                    // (see MenuManager). So if force is true we do it again. But
                    // we can't set force to false since then information for the
                    // sub sub menus is lost.
                    if (recursive) {
                        IContributionItem item = src;
                        if (item instanceof SubContributionItem)
                            item = ((SubContributionItem) item).getInnerItem();
                        if (item instanceof IMenuManager)
                            ((IMenuManager) item).updateAll(force);
                    }

                }

                // remove any old menu items not accounted for
                for (; srcIx < mi.length; srcIx++)
                    mi[srcIx].dispose();

                setDirty(false);
            }
        } else {
            // I am not dirty. Check if I must recursivly walk down the hierarchy.
            if (recursive) {
                IContributionItem[] items = getItems();
                for (int i = 0; i < items.length; ++i) {
                    IContributionItem ci = items[i];
                    if (ci instanceof IMenuManager) {
                        IMenuManager mm = (IMenuManager) ci;
                        if (mm.isVisible()) {
                            mm.updateAll(force);
                        }
                    }
                }
            }
        }
        updateMenuItem();
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IContributionItem#update(java.lang.String)
     */
    public void update(String property) {
        IContributionItem items[] = getItems();

        for (int i = 0; i < items.length; i++)
            items[i].update(property);

        if (menu != null && !menu.isDisposed() && menu.getParentItem() != null
                && IAction.TEXT.equals(property)) {
            String text = getOverrides().getText(this);

            if (text == null)
                text = getMenuText();

            if (text != null) {
                ExternalActionManager.ICallback callback = ExternalActionManager
                        .getInstance().getCallback();

                if (callback != null) {
                    int index = text.indexOf('&');

                    if (index >= 0 && index < text.length() - 1) {
                        char character = Character.toUpperCase(text
                                .charAt(index + 1));

                        if (callback.isAcceleratorInUse(SWT.ALT | character)) {
                            if (index == 0)
                                text = text.substring(1);
                            else
                                text = text.substring(0, index)
                                        + text.substring(index + 1);
                        }
                    }
                }

                menu.getParentItem().setText(text);
            }
        }
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.action.IMenuManager#updateAll(boolean)
     */
    public void updateAll(boolean force) {
        update(force, true);
    }

    /**
     * Updates the menu item for this sub menu.
     * The menu item is disabled if this sub menu is empty.
     * Does nothing if this menu is not a submenu.
     */
    private void updateMenuItem() {
        /*
         * Commented out until proper solution to enablement of
         * menu item for a sub-menu is found. See bug 30833 for
         * more details.
         *  
         if (menuItem != null && !menuItem.isDisposed() && menuExist()) {
         IContributionItem items[] = getItems();
         boolean enabled = false;
         for (int i = 0; i < items.length; i++) {
         IContributionItem item = items[i];
         enabled = item.isEnabled();
         if(enabled) break;
         }
         // Workaround for 1GDDCN2: SWT:Linux - MenuItem.setEnabled() always causes a redraw
         if (menuItem.getEnabled() != enabled)
         menuItem.setEnabled(enabled);
         }
         */
        // Partial fix for bug #34969 - diable the menu item if no
        // items in sub-menu (for context menus).
        if (menuItem != null && !menuItem.isDisposed() && menuExist()) {
            boolean enabled = menu.getItemCount() > 0;
            // Workaround for 1GDDCN2: SWT:Linux - MenuItem.setEnabled() always causes a redraw
            if (menuItem.getEnabled() != enabled) {
                // We only do this for context menus (for bug #34969)
                Menu topMenu = menu;
                while (topMenu.getParentMenu() != null)
                    topMenu = topMenu.getParentMenu();
                if ((topMenu.getStyle() & SWT.BAR) == 0)
                    menuItem.setEnabled(enabled);
            }
        }
    }
}