/*******************************************************************************
 * Copyright (c) 2000, 2015 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.ui.actions;

import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.ActionContributionItem;
import org.eclipse.jface.action.IContributionItem;
import org.eclipse.jface.action.IMenuCreator;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.ui.ISharedImages;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.internal.PerspectiveTracker;
import org.eclipse.ui.internal.WorkbenchMessages;

/**
 * Action which, when run, will open the new wizard dialog.
 * In addition, it has a drop-down showing the new wizard shortcuts
 * associated with the current perspective.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 *
 * @since 3.1
 */
public class NewWizardDropDownAction extends Action implements
        ActionFactory.IWorkbenchAction {

    /**
     * The workbench window; or <code>null</code> if this
     * action has been <code>dispose</code>d.
     */
    private IWorkbenchWindow workbenchWindow;

    /**
     * Tracks perspective activation, to update this action's
     * enabled state.
     */
    private PerspectiveTracker tracker;

    private ActionFactory.IWorkbenchAction showDlgAction;

    private IContributionItem newWizardMenu;

    private IMenuCreator menuCreator = new IMenuCreator() {

        private MenuManager dropDownMenuMgr;

        /**
         * Creates the menu manager for the drop-down.
         */
        private void createDropDownMenuMgr() {
            if (dropDownMenuMgr == null) {
                dropDownMenuMgr = new MenuManager();
                dropDownMenuMgr.add(newWizardMenu);
            }
        }

        @Override
		public Menu getMenu(Control parent) {
            createDropDownMenuMgr();
            return dropDownMenuMgr.createContextMenu(parent);
        }

        @Override
		public Menu getMenu(Menu parent) {
            createDropDownMenuMgr();
            Menu menu = new Menu(parent);
            IContributionItem[] items = dropDownMenuMgr.getItems();
            for (IContributionItem item : items) {
                IContributionItem newItem = item;
                if (item instanceof ActionContributionItem) {
                    newItem = new ActionContributionItem(
                            ((ActionContributionItem) item).getAction());
                }
                newItem.fill(menu, -1);
            }
            return menu;
        }

        @Override
		public void dispose() {
			if (dropDownMenuMgr != null) {
				// remove the wizard menu before disposing the menu manager, the
				// wizard menu is a workbench action and it should only be
				// disposed when the workbench window itself is disposed,
				// IMenuCreators will be disposed when the action is disposed,
				// we do not want this, the menu's disposal will be handled when
				// the owning action (NewWizardDropDownAction) is disposed, see
				// bug 309716
				dropDownMenuMgr.remove(newWizardMenu);

				dropDownMenuMgr.dispose();
				dropDownMenuMgr = null;
			}
        }
    };

    /**
     * Create a new <code>NewWizardDropDownAction</code>, with the default
     * action for opening the new wizard dialog, and the default contribution item
     * for populating the drop-down menu.
     *
     * @param window the window in which this action appears
     */
    public NewWizardDropDownAction(IWorkbenchWindow window) {
        this(window, ActionFactory.NEW.create(window), ContributionItemFactory.NEW_WIZARD_SHORTLIST.create(window));
    }

    /**
     * Create a new <code>NewWizardDropDownAction</code>.
     *
     * @param window the window in which this action appears
     * @param showDlgAction the action to delegate to when this action is run directly,
     *   rather than being dropped down
     * @param newWizardMenu the contribution item that adds the contents to the drop-down menu
     */
    public NewWizardDropDownAction(IWorkbenchWindow window,
            ActionFactory.IWorkbenchAction showDlgAction,
            IContributionItem newWizardMenu) {
        super(WorkbenchMessages.NewWizardDropDown_text);
        if (window == null) {
            throw new IllegalArgumentException();
        }
        this.workbenchWindow = window;
        this.showDlgAction = showDlgAction;
        this.newWizardMenu = newWizardMenu;
        tracker = new PerspectiveTracker(window, this);

        setToolTipText(showDlgAction.getToolTipText());

        ISharedImages sharedImages = window.getWorkbench()
                .getSharedImages();
        setImageDescriptor(sharedImages
                .getImageDescriptor(ISharedImages.IMG_TOOL_NEW_WIZARD));
        setDisabledImageDescriptor(sharedImages
                .getImageDescriptor(ISharedImages.IMG_TOOL_NEW_WIZARD_DISABLED));

        setMenuCreator(menuCreator);
    }


    @Override
	public void dispose() {
        if (workbenchWindow == null) {
            // action has already been disposed
            return;
        }
        tracker.dispose();
        showDlgAction.dispose();
        newWizardMenu.dispose();
        menuCreator.dispose();
        workbenchWindow = null;
    }

    /**
     * Runs the action, which opens the New wizard dialog.
     */
    @Override
	public void run() {
        if (workbenchWindow == null) {
            // action has been disposed
            return;
        }
        showDlgAction.run();
    }

}