/**
 * <copyright>
 *
 * Copyright (c) 2002-2008 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 - Initial API and implementation
 *   Obeo - Adaptation
 * </copyright>
 */

package org.eclipse.sirius.editor.editorPlugin;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

import org.eclipse.emf.common.ui.viewer.IViewerProvider;
import org.eclipse.emf.edit.domain.EditingDomain;
import org.eclipse.emf.edit.domain.IEditingDomainProvider;
import org.eclipse.emf.edit.ui.action.ControlAction;
import org.eclipse.emf.edit.ui.action.CreateChildAction;
import org.eclipse.emf.edit.ui.action.CreateSiblingAction;
import org.eclipse.emf.edit.ui.action.EditingDomainActionBarContributor;
import org.eclipse.emf.edit.ui.action.LoadResourceAction;
import org.eclipse.emf.edit.ui.action.ValidateAction;
import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.ActionContributionItem;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.action.IContributionItem;
import org.eclipse.jface.action.IContributionManager;
import org.eclipse.jface.action.IMenuListener;
import org.eclipse.jface.action.IMenuManager;
import org.eclipse.jface.action.IToolBarManager;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.jface.action.Separator;
import org.eclipse.jface.action.SubContributionItem;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.PartInitException;

/**
 * This is the action bar contributor for the Contribution model editor.
 */
public class ContributionActionBarContributor extends EditingDomainActionBarContributor implements ISelectionChangedListener {
    /**
     * This keeps track of the active editor.
     */
    protected IEditorPart activeEditorPart;

    /**
     * This keeps track of the current selection provider.
     */
    protected ISelectionProvider selectionProvider;

    /**
     * This action opens the Properties view.
     */
    protected IAction showPropertiesViewAction = new Action(SiriusEditorPlugin.INSTANCE.getString("_UI_ShowPropertiesView_menu_item")) {
        public void run() {
            try {
                getPage().showView("org.eclipse.ui.views.PropertySheet");
            } catch (PartInitException exception) {
                SiriusEditorPlugin.INSTANCE.log(exception);
            }
        }
    };

    /**
     * This action refreshes the viewer of the current editor if the editor
     * implements {@link org.eclipse.emf.common.ui.viewer.IViewerProvider}.
     */
    protected IAction refreshViewerAction = new Action(SiriusEditorPlugin.INSTANCE.getString("_UI_RefreshViewer_menu_item")) {
        public boolean isEnabled() {
            return activeEditorPart instanceof IViewerProvider;
        }

        public void run() {
            if (activeEditorPart instanceof IViewerProvider) {
                Viewer viewer = ((IViewerProvider) activeEditorPart).getViewer();
                if (viewer != null) {
                    viewer.refresh();
                }
            }
        }
    };

    /**
     * This will contain one
     * {@link org.eclipse.emf.edit.ui.action.CreateChildAction} corresponding to
     * each descriptor generated for the current selection by the item provider.
     */
    protected Collection<IAction> createChildActions;

    /**
     * This is the menu manager into which menu contribution items should be
     * added for CreateChild actions.
     */
    protected IMenuManager createChildMenuManager;

    /**
     * This will contain one
     * {@link org.eclipse.emf.edit.ui.action.CreateSiblingAction} corresponding
     * to each descriptor generated for the current selection by the item
     * provider.
     */
    protected Collection<IAction> createSiblingActions;

    /**
     * This is the menu manager into which menu contribution items should be
     * added for CreateSibling actions.
     */
    protected IMenuManager createSiblingMenuManager;

    /**
     * This creates an instance of the contributor.
     */
    public ContributionActionBarContributor() {
        super(ADDITIONS_LAST_STYLE);
        loadResourceAction = new LoadResourceAction();
        validateAction = new ValidateAction();
        controlAction = new ControlAction();
    }

    /**
     * This adds Separators for editor additions to the tool bar.
     */
    public void contributeToToolBar(IToolBarManager toolBarManager) {
        toolBarManager.add(new Separator("contribution-settings"));
        toolBarManager.add(new Separator("contribution-additions"));
    }

    /**
     * This adds to the menu bar a menu and some separators for editor
     * additions, as well as the sub-menus for object creation items.
     */
    public void contributeToMenu(IMenuManager menuManager) {
        super.contributeToMenu(menuManager);

        IMenuManager submenuManager = new MenuManager(SiriusEditorPlugin.INSTANCE.getString("_UI_SiriusEditor_menu"), "contributionMenuID");
        menuManager.insertAfter("additions", submenuManager);
        submenuManager.add(new Separator("settings"));
        submenuManager.add(new Separator("actions"));
        submenuManager.add(new Separator("additions"));
        submenuManager.add(new Separator("additions-end"));

        // Prepare for CreateChild item addition or removal.
        //
        createChildMenuManager = new MenuManager(SiriusEditorPlugin.INSTANCE.getString("_UI_CreateChild_menu_item"));
        submenuManager.insertBefore("additions", createChildMenuManager);

        // Prepare for CreateSibling item addition or removal.
        //
        createSiblingMenuManager = new MenuManager(SiriusEditorPlugin.INSTANCE.getString("_UI_CreateSibling_menu_item"));
        submenuManager.insertBefore("additions", createSiblingMenuManager);

        // Force an update because Eclipse hides empty menus now.
        //
        submenuManager.addMenuListener(new IMenuListener() {
            public void menuAboutToShow(IMenuManager menuManager) {
                menuManager.updateAll(true);
            }
        });

        addGlobalActions(submenuManager);
    }

    /**
     * When the active editor changes, this remembers the change and registers
     * with it as a selection provider.
     */
    public void setActiveEditor(IEditorPart part) {
        super.setActiveEditor(part);
        activeEditorPart = part;

        // Switch to the new selection provider.
        //
        if (selectionProvider != null) {
            selectionProvider.removeSelectionChangedListener(this);
        }
        if (part == null) {
            selectionProvider = null;
        } else {
            selectionProvider = part.getSite().getSelectionProvider();
            selectionProvider.addSelectionChangedListener(this);

            // Fake a selection changed event to update the menus.
            //
            if (selectionProvider.getSelection() != null) {
                selectionChanged(new SelectionChangedEvent(selectionProvider, selectionProvider.getSelection()));
            }
        }
    }

    /**
     * This implements
     * {@link org.eclipse.jface.viewers.ISelectionChangedListener}, handling
     * {@link org.eclipse.jface.viewers.SelectionChangedEvent}s by querying for
     * the children and siblings that can be added to the selected object and
     * updating the menus accordingly.
     */
    public void selectionChanged(SelectionChangedEvent event) {
        // Remove any menu items for old selection.
        //
        if (createChildMenuManager != null) {
            depopulateManager(createChildMenuManager, createChildActions);
        }
        if (createSiblingMenuManager != null) {
            depopulateManager(createSiblingMenuManager, createSiblingActions);
        }

        // Query the new selection for appropriate new child/sibling descriptors
        //
        Collection<?> newChildDescriptors = null;
        Collection<?> newSiblingDescriptors = null;

        ISelection selection = event.getSelection();
        if (selection instanceof IStructuredSelection && ((IStructuredSelection) selection).size() == 1) {
            Object object = ((IStructuredSelection) selection).getFirstElement();

            EditingDomain domain = ((IEditingDomainProvider) activeEditorPart).getEditingDomain();

            newChildDescriptors = domain.getNewChildDescriptors(object, null);
            newSiblingDescriptors = domain.getNewChildDescriptors(null, object);
        }

        // Generate actions for selection; populate and redraw the menus.
        //
        createChildActions = generateCreateChildActions(newChildDescriptors, selection);
        createSiblingActions = generateCreateSiblingActions(newSiblingDescriptors, selection);

        if (createChildMenuManager != null) {
            populateManager(createChildMenuManager, createChildActions, null);
            createChildMenuManager.update(true);
        }
        if (createSiblingMenuManager != null) {
            populateManager(createSiblingMenuManager, createSiblingActions, null);
            createSiblingMenuManager.update(true);
        }
    }

    /**
     * This generates a {@link org.eclipse.emf.edit.ui.action.CreateChildAction}
     * for each object in <code>descriptors</code>, and returns the collection
     * of these actions.
     */
    protected Collection<IAction> generateCreateChildActions(Collection<?> descriptors, ISelection selection) {
        Collection<IAction> actions = new ArrayList<IAction>();
        if (descriptors != null) {
            for (Iterator<?> i = descriptors.iterator(); i.hasNext();) {
                actions.add(new CreateChildAction(activeEditorPart, selection, i.next()));
            }
        }
        return actions;
    }

    /**
     * This generates a
     * {@link org.eclipse.emf.edit.ui.action.CreateSiblingAction} for each
     * object in <code>descriptors</code>, and returns the collection of these
     * actions.
     */
    protected Collection<IAction> generateCreateSiblingActions(Collection<?> descriptors, ISelection selection) {
        Collection<IAction> actions = new ArrayList<IAction>();
        if (descriptors != null) {
            for (Iterator<?> i = descriptors.iterator(); i.hasNext();) {
                actions.add(new CreateSiblingAction(activeEditorPart, selection, i.next()));
            }
        }
        return actions;
    }

    /**
     * This populates the specified <code>manager</code> with
     * {@link org.eclipse.jface.action.ActionContributionItem}s based on the
     * {@link org.eclipse.jface.action.IAction}s contained in the
     * <code>actions</code> collection, by inserting them before the specified
     * contribution item <code>contributionID</code>. If <code>ID</code> is
     * <code>null</code>, they are simply added.
     */
    protected void populateManager(IContributionManager manager, Collection<IAction> actions, String contributionID) {
        if (actions != null) {
            for (Iterator<IAction> i = actions.iterator(); i.hasNext();) {
                IAction action = i.next();
                if (contributionID != null) {
                    manager.insertBefore(contributionID, action);
                } else {
                    manager.add(action);
                }
            }
        }
    }

    /**
     * This removes from the specified <code>manager</code> all
     * {@link org.eclipse.jface.action.ActionContributionItem}s based on the
     * {@link org.eclipse.jface.action.IAction}s contained in the
     * <code>actions</code> collection.
     */
    protected void depopulateManager(IContributionManager manager, Collection<IAction> actions) {
        if (actions != null) {
            IContributionItem[] items = manager.getItems();
            for (int i = 0; i < items.length; i++) {
                // Look into SubContributionItems
                //
                IContributionItem contributionItem = items[i];
                while (contributionItem instanceof SubContributionItem) {
                    contributionItem = ((SubContributionItem) contributionItem).getInnerItem();
                }

                // Delete the ActionContributionItems with matching action.
                //
                if (contributionItem instanceof ActionContributionItem) {
                    IAction action = ((ActionContributionItem) contributionItem).getAction();
                    if (actions.contains(action)) {
                        manager.remove(contributionItem);
                    }
                }
            }
        }
    }

    /**
     * This populates the pop-up menu before it appears.
     */
    public void menuAboutToShow(IMenuManager menuManager) {
        super.menuAboutToShow(menuManager);
        MenuManager submenuManager = null;

        submenuManager = new MenuManager(SiriusEditorPlugin.INSTANCE.getString("_UI_CreateChild_menu_item"));
        populateManager(submenuManager, createChildActions, null);
        menuManager.insertBefore("edit", submenuManager);

        submenuManager = new MenuManager(SiriusEditorPlugin.INSTANCE.getString("_UI_CreateSibling_menu_item"));
        populateManager(submenuManager, createSiblingActions, null);
        menuManager.insertBefore("edit", submenuManager);
    }

    /**
     * This inserts global actions before the "additions-end" separator.
     */
    protected void addGlobalActions(IMenuManager menuManager) {
        menuManager.insertAfter("additions-end", new Separator("ui-actions"));
        menuManager.insertAfter("ui-actions", showPropertiesViewAction);

        refreshViewerAction.setEnabled(refreshViewerAction.isEnabled());
        menuManager.insertAfter("ui-actions", refreshViewerAction);

        super.addGlobalActions(menuManager);
    }

    /**
     * This ensures that a delete action will clean up all references to deleted
     * objects.
     */
    protected boolean removeAllReferencesOnDelete() {
        return true;
    }
}