/**
 *                                                                            
 *  Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany) 
 *                                                                            
 *  All rights reserved. This program and the accompanying materials           
 *  are made available under the terms of the Eclipse Public License 2.0        
 *  which accompanies this distribution, and is available at                  
 *  https://www.eclipse.org/legal/epl-2.0/                                 
 *                                 
 *  SPDX-License-Identifier: EPL-2.0                                 
 *                                                                            
 *  Contributors:                                                      
 * 	   Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation
 * 
 */
package org.eclipse.osbp.vaadin.emf.actions;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.edit.command.CommandParameter;
import org.eclipse.emf.edit.command.CreateChildCommand;
import org.eclipse.emf.edit.command.RemoveCommand;
import org.eclipse.emf.edit.domain.EditingDomain;
import org.eclipse.osbp.runtime.web.vaadin.common.resource.IResourceProvider;
import org.eclipse.osbp.vaadin.emf.api.IModelingContext;
import org.eclipse.osbp.vaadin.emf.data.EmfModelTreeContainer;

import com.vaadin.event.Action;
import com.vaadin.server.Resource;
import com.vaadin.ui.AbstractSelect;

/**
 * A Vaadin ActionHandler that is aware about all containment references that
 * can be created for a single EObject.
 */
@SuppressWarnings("serial")
public class EObjectActionHandler implements Action.Handler {

	private EditCallback callback;
	private IModelingContext modelingContext;
	private IResourceProvider resourceProvider;

	public EObjectActionHandler(IModelingContext modelingContext,
			IResourceProvider resourceProvider, EditCallback callback) {
		this.modelingContext = modelingContext;
		this.resourceProvider = resourceProvider;
		this.callback = callback;
	}

	/**
	 * Gets the list of actions applicable to this handler.
	 * 
	 * @param target
	 *            the target handler to list actions for. For item containers
	 *            this is the item id.
	 * @param sender
	 *            the party that would be sending the actions. Most of this is
	 *            the action container.
	 * @return the list of Action
	 */
	@SuppressWarnings("unchecked")
	public Action[] getActions(Object target, Object sender) {

		List<CustomAction> result = new ArrayList<>();
		if (target != null) {
			CustomAction editAction = new CustomAction(Commands.EDIT_DIALOG,
					"Edit", null, null);
			editAction.modelElement = (EObject) target;
			result.add(editAction);

			result.add(new CustomAction(Commands.REFRESH_NODE, "Refresh", null,
					null));

			if (canDelete(target)) {
				result.add(new CustomAction(Commands.DELETE, "Delete", null,
						null));
			}

			if (modelingContext.getCommandStack().canUndo()) {
				result.add(new CustomAction(Commands.UNDO, "Undo", null, null));
			}

			if (modelingContext.getCommandStack().canRedo()) {
				result.add(new CustomAction(Commands.REDO, "Redo", null, null));
			}
		}

		return result.toArray(new Action[result.size()]);
	}

	private boolean canDelete(Object target) {
		Command command = RemoveCommand.create(
				modelingContext.getEditingDomain(), target);
		return command.canExecute();
	}

	/**
	 * Handles an action for the given target. The handler method may just
	 * discard the action if it's not suitable.
	 * 
	 * @param action
	 *            the action to be handled.
	 * @param sender
	 *            the sender of the action. This is most often the action
	 *            container.
	 * @param target
	 *            the target of the action. For item containers this is the item
	 *            id.
	 */
	public void handleAction(Action action, Object sender, Object target) {
		CustomAction customAction = (CustomAction) action;

		EditingDomain domain = modelingContext.getEditingDomain();
		if (customAction.getCommand() == Commands.CREATE_CHILD) {
			CommandParameter executeParam = new CommandParameter(target,
					customAction.getParam().getFeature(),
					customAction.getParam());
			Command command = domain.createCommand(CreateChildCommand.class,
					executeParam);
			domain.getCommandStack().execute(command);
		} else if (customAction.getCommand() == Commands.DELETE) {
			domain.getCommandStack().execute(
					RemoveCommand.create(domain, target));
		} else if (customAction.getCommand() == Commands.UNDO) {
			domain.getCommandStack().undo();
		} else if (customAction.getCommand() == Commands.REDO) {
			domain.getCommandStack().redo();
		} else if (customAction.getCommand() == Commands.REFRESH_NODE) {
			AbstractSelect select = (AbstractSelect) sender;
			EmfModelTreeContainer container = (EmfModelTreeContainer) select
					.getContainerDataSource();
			container.refreshNode(target);
		} else if (customAction.getCommand() == Commands.EDIT_DIALOG) {
			callback.edit(customAction.modelElement);
		}
	}

	/**
	 * Custom action wraps CommandParameter.
	 */
	private static class CustomAction extends Action {

		private final Commands command;
		private final CommandParameter param;
		private final EStructuralFeature feature;
		private EObject modelElement;

		public CustomAction(Commands command, String caption, Resource icon,
				CommandParameter param) {
			super(caption, icon);
			this.command = command;
			this.param = param;
			this.feature = null;
		}

		public CustomAction(Commands command, String caption, Resource icon,
				CommandParameter param, EStructuralFeature feature) {
			super(caption, icon);
			this.command = command;
			this.param = param;
			this.feature = feature;
		}

		public CustomAction(Commands command, String caption, Resource icon) {
			super(caption, icon);
			this.command = command;
			this.param = null;
			this.feature = null;
		}

		public CommandParameter getParam() {
			return param;
		}

		public Commands getCommand() {
			return command;
		}

		public EStructuralFeature getFeature() {
			return feature;
		}

	}

	enum Commands {
		EDIT_DIALOG, CREATE_CHILD, DELETE, UNDO, REDO, COPY, PASTE, REFRESH_NODE
	}

	public interface EditCallback {
		void edit(EObject model);
	}
}