/*******************************************************************************
 * Copyright (c) 2013 CEA LIST.
 * 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:
 *     Cedric Dumoulin - cedric.dumoulin@lifl.fr
 ******************************************************************************/
/**
 */
package org.eclipse.papyrus.infra.gmfdiag.layers.diagram;

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

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.CopyAction;
import org.eclipse.emf.edit.ui.action.CreateChildAction;
import org.eclipse.emf.edit.ui.action.CreateSiblingAction;
import org.eclipse.emf.edit.ui.action.CutAction;
import org.eclipse.emf.edit.ui.action.DeleteAction;
import org.eclipse.emf.edit.ui.action.LoadResourceAction;
import org.eclipse.emf.edit.ui.action.PasteAction;
import org.eclipse.emf.edit.ui.action.RedoAction;
import org.eclipse.emf.edit.ui.action.UndoAction;
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.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.papyrus.internal.infra.gmfdiag.layers.model.layers.presentation.LayersActionBarContributor;
import org.eclipse.papyrus.internal.infra.gmfdiag.layers.model.layers.presentation.LayersEditorPlugin;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IWorkbenchPage;
import org.eclipse.ui.PartInitException;

/**
 *
 * This class manage the dynamic menu for Layer diagram.
 * It is a modification of the original {@link LayersActionBarContributor}. <br>
 * Code is copied from the generated {@link LayersActionBarContributor}.
 * Changes are made in order to work with Papyrus.
 *
 * <!-- begin-user-doc -->
 * <!-- end-user-doc -->
 *
 * @generated
 */
public class DynamicContextMenu implements ISelectionChangedListener {
	/**
	 * This keeps track of the active editor.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected IEditorPart activeEditorPart;

	/**
	 * This keeps track of the current selection provider.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected ISelectionProvider selectionProvider;

	/**
	 * The workbench page; <code>null</code> until <code>init</code> is called.
	 */
	private IWorkbenchPage page;

	/**
	 * This action opens the Properties view.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected IAction showPropertiesViewAction = new Action(LayersEditorPlugin.INSTANCE.getString("_UI_ShowPropertiesView_menu_item")) {
		@Override
		public void run() {
			try {
				getPage().showView("org.eclipse.ui.views.PropertySheet");
			} catch (PartInitException exception) {
				LayersEditorPlugin.INSTANCE.log(exception);
			}
		}
	};

	/**
	 * This action refreshes the viewer of the current editor if the editor
	 * implements {@link org.eclipse.emf.common.ui.viewer.IViewerProvider}.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected IAction refreshViewerAction = new Action(LayersEditorPlugin.INSTANCE.getString("_UI_RefreshViewer_menu_item")) {
		@Override
		public boolean isEnabled() {
			return activeEditorPart instanceof IViewerProvider;
		}

		@Override
		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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected Collection<IAction> createChildActions;

	/**
	 * This is the menu manager into which menu contribution items should be added for CreateChild actions.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected Collection<IAction> createSiblingActions;

	/**
	 * This is the menu manager into which menu contribution items should be added for CreateSibling actions.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected IMenuManager createSiblingMenuManager;

	/**
	 * This is the action used to implement delete.
	 */
	protected DeleteAction deleteAction;

	/**
	 * This is the action used to implement cut.
	 */
	protected CutAction cutAction;

	/**
	 * This is the action used to implement copy.
	 */
	protected CopyAction copyAction;

	/**
	 * This is the action used to implement paste.
	 */
	protected PasteAction pasteAction;

	/**
	 * This is the action used to implement undo.
	 */
	protected UndoAction undoAction;

	/**
	 * This is the action used to implement redo.
	 */
	protected RedoAction redoAction;

	/**
	 * This is the action used to load a resource.
	 */
	protected LoadResourceAction loadResourceAction;

	/**
	 * This is the action used to control or uncontrol a contained object.
	 */
	protected ControlAction controlAction;

	/**
	 * This is the action used to perform validation.
	 */
	protected ValidateAction validateAction;

	/**
	 * This creates an instance of the contributor.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	public DynamicContextMenu(IEditorPart part) {
		loadResourceAction = new LoadResourceAction();
		validateAction = new ValidateAction();
		controlAction = new ControlAction();

		// Added init
		this.page = part.getEditorSite().getPage();
		setActiveEditor(part);

		MenuManager menuManager = new MenuManager();
		menuManager.add(new Separator("additions"));
		menuManager.add(new Separator("edit"));
		contributeToMenu(menuManager);
	}

	/**
	 * This adds to the menu bar a menu and some separators for editor additions,
	 * as well as the sub-menus for object creation items.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	public void contributeToMenu(IMenuManager menuManager) {

		IMenuManager submenuManager = new MenuManager(LayersEditorPlugin.INSTANCE.getString("_UI_LayersEditor_menu"), "org.eclipse.papyrus.internal.infra.gmfdiag.layers.model.layersMenuID");
		// menuManager.insertAfter("additions", submenuManager);
		menuManager.add(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(LayersEditorPlugin.INSTANCE.getString("_UI_CreateChild_menu_item"));
		submenuManager.insertBefore("additions", createChildMenuManager);

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

		// Force an update because Eclipse hides empty menus now.
		//
		submenuManager.addMenuListener(new IMenuListener() {
			@Override
			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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	public void setActiveEditor(IEditorPart 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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	@Override
	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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected Collection<IAction> generateCreateChildActions(Collection<?> descriptors, ISelection selection) {
		Collection<IAction> actions = new ArrayList<IAction>();
		if (descriptors != null) {
			for (Object descriptor : descriptors) {
				actions.add(new CreateChildAction(activeEditorPart, selection, descriptor));
			}
		}
		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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected Collection<IAction> generateCreateSiblingActions(Collection<?> descriptors, ISelection selection) {
		Collection<IAction> actions = new ArrayList<IAction>();
		if (descriptors != null) {
			for (Object descriptor : descriptors) {
				actions.add(new CreateSiblingAction(activeEditorPart, selection, descriptor));
			}
		}
		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>contributionID</code> is <code>null</code>, they are simply added.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected void populateManager(IContributionManager manager, Collection<? extends IAction> actions, String contributionID) {
		if (actions != null) {
			for (IAction action : actions) {
				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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	protected void depopulateManager(IContributionManager manager, Collection<? extends 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.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	public void menuAboutToShow(IMenuManager menuManager) {

		// System.err.println("menuAboutToShow("+ menuManager.getId()+ ")");
		MenuManager submenuManager = null;

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

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

	/**
	 * This inserts global actions before the "additions-end" separator.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 *
	 * @generated
	 */
	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);

	}

	/**
	 * Returns this contributor's workbench page.
	 *
	 * @return the workbench page
	 */
	public IWorkbenchPage getPage() {
		return page;
	}


}