/*******************************************************************************
 * Copyright (c) 2000, 2008 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.simantics.browsing.ui.platform;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.Platform;
import org.eclipse.e4.core.contexts.ContextFunction;
import org.eclipse.e4.core.contexts.IEclipseContext;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IActionBars;
import org.eclipse.ui.IViewSite;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.SubActionBars;
import org.eclipse.ui.contexts.IContextService;
import org.eclipse.ui.handlers.IHandlerService;
import org.eclipse.ui.internal.PartSite;
import org.eclipse.ui.internal.PopupMenuExtender;
import org.eclipse.ui.internal.contexts.NestableContextService;
import org.eclipse.ui.internal.expressions.ActivePartExpression;
import org.eclipse.ui.internal.handlers.LegacyHandlerService;
import org.eclipse.ui.internal.part.IPageSiteHolder;
import org.eclipse.ui.internal.services.INestable;
import org.eclipse.ui.internal.services.IServiceLocatorCreator;
import org.eclipse.ui.internal.services.IWorkbenchLocationService;
import org.eclipse.ui.internal.services.ServiceLocator;
import org.eclipse.ui.internal.services.WorkbenchLocationService;
import org.eclipse.ui.part.IPageSite;
import org.eclipse.ui.services.IDisposable;
import org.eclipse.ui.services.IServiceScopes;

/**
 * This implementation of <code>IPageSite</code> provides a site for a page
 * within a <code>PageBookView</code>. Most methods are forwarded to the view's
 * site.
 * 
 * Carbon copy of {@link org.eclipse.ui.part.PageSite}, had to copy this too
 * when PageBookView was copied, PageBookView refers to protected
 * PageSite.dispose().
 * 
 * @author Tuukka Lehtonen
 */
@SuppressWarnings({"restriction","rawtypes"})
public class PageSite implements IPageSite, INestable {

    /**
     * The list of menu extender for each registered menu.
     */
    private ArrayList menuExtenders;

    /**
     * The "parent" view site
     */
    private final IViewSite parentSite;

    /**
     * A selection provider set by the page. Value is <code>null</code> until
     * set.
     */
    private ISelectionProvider selectionProvider;

    /**
     * The localized service locator for this page site. This locator is never
     * <code>null</code>.
     */
    private final ServiceLocator serviceLocator;

    /**
     * The action bars for this site
     */
    private final SubActionBars subActionBars;

    private IEclipseContext e4Context;

    private NestableContextService contextService;

    private boolean active = false;

    /**
     * Creates a new sub view site of the given parent view site.
     * 
     * @param parentViewSite
     *            the parent view site
     */
    public PageSite(final IViewSite parentViewSite) {
        Assert.isNotNull(parentViewSite);
        parentSite = parentViewSite;
        subActionBars = new SubActionBars(parentViewSite.getActionBars(), this);

        // Initialize the service locator.
        IServiceLocatorCreator slc = (IServiceLocatorCreator) parentSite
                .getService(IServiceLocatorCreator.class);
        this.serviceLocator = (ServiceLocator) slc.createServiceLocator(parentViewSite, null,
                new IDisposable() {
                    public void dispose() {
                        // final Control control =
                        // ((PartSite)parentViewSite).getPane().getControl();
                        // if (control != null && !control.isDisposed()) {
                        // ((PartSite)parentViewSite).getPane().doHide();
                        // }
                        // TODO compat: not tsure what this should do
                    }
                });
        e4Context = ((PartSite) parentViewSite).getContext().createChild("PageSite"); //$NON-NLS-1$
        serviceLocator.setContext(e4Context);
        initializeDefaultServices();
    }

    /**
     * Initialize the slave services for this site.
     */
    private void initializeDefaultServices() {
        serviceLocator.registerService(IWorkbenchLocationService.class,
                new WorkbenchLocationService(IServiceScopes.PAGESITE_SCOPE,
                        getWorkbenchWindow().getWorkbench(),
                        getWorkbenchWindow(), parentSite, null, this, 3));
        serviceLocator.registerService(IPageSiteHolder.class,
                new IPageSiteHolder() {
                    public IPageSite getSite() {
                        return PageSite.this;
                    }
                });

        // create a local handler service so that when this page
        // activates/deactivates, its handlers will also be taken into/out of
        // consideration during handler lookups
        IHandlerService handlerService = new LegacyHandlerService(e4Context);
        e4Context.set(IHandlerService.class, handlerService);

        e4Context.set(IContextService.class.getName(), new ContextFunction() {
            @Override
            public Object compute(IEclipseContext context) {
                if (contextService == null) {
                    contextService = new NestableContextService(context.getParent().get(
                            IContextService.class), new ActivePartExpression(parentSite.getPart()));
                }
                return contextService;
            }
        });
    }

    /**
     * Disposes of the menu extender contributions.
     */
    @SuppressWarnings("unchecked")
    protected void dispose() {
        if (menuExtenders != null) {
            HashSet managers = new HashSet(menuExtenders.size());
            for (int i = 0; i < menuExtenders.size(); i++) {
                PopupMenuExtender ext = (PopupMenuExtender) menuExtenders.get(i);
                managers.add(ext.getManager());
                ext.dispose();
            }
            if (managers.size()>0) {
                for (Iterator iterator = managers.iterator(); iterator
                .hasNext();) {
                    MenuManager mgr = (MenuManager) iterator.next();
                    mgr.dispose();
                }
            }
            menuExtenders = null;
        }
        subActionBars.dispose();

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

        serviceLocator.dispose();
        e4Context.dispose();
    }

    /**
     * The PageSite implementation of this <code>IPageSite</code> method
     * returns the <code>SubActionBars</code> for this site.
     * 
     * @return the subactionbars for this site
     */
    @Override
    public IActionBars getActionBars() {
        return subActionBars;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.core.runtime.IAdaptable#getAdapter(java.lang.Class)
     */
    @Override
    public <T> T getAdapter(Class<T> adapter) {
        return Platform.getAdapterManager().getAdapter(this, adapter);
    }

    /*
     * (non-Javadoc) Method declared on IPageSite.
     */
    @Override
    public IWorkbenchPage getPage() {
        return parentSite.getPage();
    }

    /*
     * (non-Javadoc) Method declared on IPageSite.
     */
    @Override
    public ISelectionProvider getSelectionProvider() {
        return selectionProvider;
    }

    @Override
    public final Object getService(final Class key) {
        Object service = serviceLocator.getService(key);
        if (active && service instanceof INestable) {
            ((INestable) service).activate();
        }
        return service;
    }

    /*
     * (non-Javadoc) Method declared on IPageSite.
     */
    @Override
    public Shell getShell() {
        return parentSite.getShell();
    }

    /*
     * (non-Javadoc) Method declared on IPageSite.
     */
    @Override
    public IWorkbenchWindow getWorkbenchWindow() {
        return parentSite.getWorkbenchWindow();
    }

    @Override
    public final boolean hasService(final Class key) {
        return serviceLocator.hasService(key);
    }

    /*
     * (non-Javadoc) Method declared on IPageSite.
     */
    @Override
    public void registerContextMenu(String menuID, MenuManager menuMgr,
            ISelectionProvider selProvider) {
        if (menuExtenders == null) {
            menuExtenders = new ArrayList(1);
        }
        PartSite.registerContextMenu(menuID, menuMgr, selProvider, false,
                parentSite.getPart(), e4Context, menuExtenders);
    }

    /*
     * (non-Javadoc) Method declared on IPageSite.
     */
    @Override
    public void setSelectionProvider(ISelectionProvider provider) {
        selectionProvider = provider;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.internal.services.INestable#activate()
     * 
     * @since 3.2
     */
    @Override
    public void activate() {
        active = true;
        e4Context.activate();
        serviceLocator.activate();

        if (contextService != null) {
            contextService.activate();
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.internal.services.INestable#deactivate()
     * 
     * @since 3.2
     */
    @Override
    public void deactivate() {
        active = false;
        if (contextService != null) {
            contextService.deactivate();
        }

        serviceLocator.deactivate();
        e4Context.deactivate();
    }
}