/*
 * Copyright (c) 2005, 2007 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 implementation
 *
 */
package org.eclipse.epf.diagram.ad.edit.policies;

import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.gef.EditPart;
import org.eclipse.gef.Request;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.commands.CompoundCommand;
import org.eclipse.gef.commands.UnexecutableCommand;
import org.eclipse.gef.editparts.AbstractConnectionEditPart;
import org.eclipse.gef.editpolicies.ConnectionEditPolicy;
import org.eclipse.gef.requests.GroupRequest;
import org.eclipse.gmf.runtime.diagram.core.commands.DeleteCommand;
import org.eclipse.gmf.runtime.diagram.ui.commands.ICommandProxy;
import org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart;
import org.eclipse.gmf.runtime.diagram.ui.editparts.IGraphicalEditPart;
import org.eclipse.gmf.runtime.diagram.ui.l10n.DiagramUIMessages;
import org.eclipse.gmf.runtime.diagram.ui.preferences.IPreferenceConstants;
import org.eclipse.gmf.runtime.diagram.ui.requests.EditCommandRequestWrapper;
import org.eclipse.gmf.runtime.diagram.ui.requests.GroupRequestViaKeyboard;
import org.eclipse.gmf.runtime.emf.type.core.requests.DestroyElementRequest;
import org.eclipse.gmf.runtime.notation.View;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.MessageDialogWithToggle;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.util.Assert;
import org.eclipse.swt.widgets.Display;

/**
 * @generated
 */
public class UMLReferenceConnectionEditPolicy extends ConnectionEditPolicy {

	/**
	 * @generated
	 */
	private static final String DELETE_FROM_DIAGRAM_DLG_TITLE = DiagramUIMessages.PromptingDeleteAction_DeleteFromDiagramDialog_Title;

	/**
	 * @generated
	 */
	private static final String DELETE_FROM_DIAGRAM_DLG_MESSAGE = DiagramUIMessages.PromptingDeleteAction_DeleteFromDiagramDialog_Message;

	/**
	 * @generated
	 */
	private static final String DELETE_FROM_MODEL_DLG_TOGGLE_LABEL = DiagramUIMessages.MessageDialogWithToggle_DoNotPromptAgainToggle_label;

	/**
	 * @generated
	 */
	protected final Command getDeleteCommand(GroupRequest deleteRequest) {
		boolean isDeleteFromKeyBoard = deleteRequest instanceof GroupRequestViaKeyboard;
		if (shouldDeleteSemantic()) {
			return createDeleteSemanticCommand(deleteRequest);
		} else {
			boolean proceedToDeleteView = true;
			if (isDeleteFromKeyBoard) {
				GroupRequestViaKeyboard groupRequestViaKeyboard = (GroupRequestViaKeyboard) deleteRequest;
				if (groupRequestViaKeyboard.isShowInformationDialog()) {
					proceedToDeleteView = showPrompt();
					groupRequestViaKeyboard.setShowInformationDialog(false);
					if (!(proceedToDeleteView))
						return UnexecutableCommand.INSTANCE;
				}
			}
			return createDeleteViewCommand(deleteRequest);
		}
	}

	/**
	 * @generated
	 */
	protected boolean shouldDeleteSemantic() {
		Assert.isTrue(getHost() instanceof AbstractConnectionEditPart);
		AbstractConnectionEditPart cep = (AbstractConnectionEditPart) getHost();
		boolean isCanonical = false;
		if (cep.getSource() != null)
			isCanonical = IsCanonical(cep.getSource());
		if (cep.getTarget() != null)
			return isCanonical ? isCanonical : IsCanonical(cep.getTarget());
		return isCanonical;
	}

	/**
	 * @generated
	 */
	private boolean IsCanonical(EditPart ep) {
		EditPart parent = ep.getParent();
		return parent instanceof GraphicalEditPart ? ((GraphicalEditPart) parent)
				.isCanonical()
				: false;
	}

	/**
	 * @generated
	 */
	protected Command createDeleteViewCommand(GroupRequest deleteRequest) {
		TransactionalEditingDomain editingDomain = ((IGraphicalEditPart) getHost())
				.getEditingDomain();
		return new ICommandProxy(new DeleteCommand(editingDomain,
				(View) getHost().getModel()));
	}

	/**
	 * @generated
	 */
	protected Command createDeleteSemanticCommand(GroupRequest deleteRequest) {
		TransactionalEditingDomain editingDomain = ((IGraphicalEditPart) getHost())
				.getEditingDomain();
		EditCommandRequestWrapper semReq = new EditCommandRequestWrapper(
				new DestroyElementRequest(editingDomain, false), deleteRequest
						.getExtendedData());
		Command semanticCmd = getHost().getCommand(semReq);
		if (semanticCmd != null && semanticCmd.canExecute()) {
			CompoundCommand cc = new CompoundCommand();
			cc.add(semanticCmd);
			return cc;
		}
		return null;
	}

	/**
	 * @generated
	 */
	private boolean showPrompt() {
		boolean prompt = ((IPreferenceStore) ((IGraphicalEditPart) getHost())
				.getDiagramPreferencesHint().getPreferenceStore())
				.getBoolean(IPreferenceConstants.PREF_PROMPT_ON_DEL_FROM_DIAGRAM);
		if (prompt)
			if (showMessageDialog())
				return true;
			else
				return false;
		return true;
	}

	/**
	 * @generated
	 */
	private boolean showMessageDialog() {
		MessageDialogWithToggle dialog = MessageDialogWithToggle
				.openYesNoQuestion(Display.getCurrent().getActiveShell(),
						DELETE_FROM_DIAGRAM_DLG_TITLE,
						DELETE_FROM_DIAGRAM_DLG_MESSAGE,
						DELETE_FROM_MODEL_DLG_TOGGLE_LABEL, false,
						(IPreferenceStore) ((IGraphicalEditPart) getHost())
								.getDiagramPreferencesHint()
								.getPreferenceStore(),
						IPreferenceConstants.PREF_PROMPT_ON_DEL_FROM_DIAGRAM);
		if (dialog.getReturnCode() == IDialogConstants.YES_ID)
			return true;
		else
			return false;
	}

	/**
	 * @generated
	 */
	public Command getCommand(Request request) {
		if (request instanceof GroupRequestViaKeyboard) {
			return getDeleteCommand((GroupRequest) request);
		}
		return super.getCommand(request);
	}
}