/*******************************************************************************
 * <copyright>
 *
 * Copyright (c) 2013, 2013 SAP AG.
 * 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:
 *    SAP AG - initial API, implementation and documentation
 *
 * </copyright>
 *
 *******************************************************************************/
package org.eclipse.fmc.blockdiagram.editor.features;

import org.eclipse.graphiti.features.IDirectEditingFeature;
import org.eclipse.graphiti.features.IDirectEditingInfo;
import org.eclipse.graphiti.features.IFeatureProvider;
import org.eclipse.graphiti.features.context.ICustomContext;
import org.eclipse.graphiti.features.context.impl.DirectEditingContext;
import org.eclipse.graphiti.features.custom.AbstractCustomFeature;
import org.eclipse.graphiti.mm.algorithms.AbstractText;
import org.eclipse.graphiti.mm.algorithms.GraphicsAlgorithm;
import org.eclipse.graphiti.mm.pictograms.ContainerShape;
import org.eclipse.graphiti.mm.pictograms.PictogramElement;
import org.eclipse.graphiti.mm.pictograms.Shape;

/**
 * This class is responsible for enabling direct editing behavior in case of
 * double click on the shape.
 * 
 * @author Benjamin Schmeling
 * 
 */
public class DirectEditingDoubleclickFeature extends AbstractCustomFeature {

	/**
	 * Main constructor.
	 * 
	 * @param featureProvider The feature provider.
	 */
	public DirectEditingDoubleclickFeature(IFeatureProvider featureProvider) {
		super(featureProvider);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.graphiti.features.custom.AbstractCustomFeature#canExecute
	 * (org.eclipse.graphiti.features.context.ICustomContext)
	 */
	@Override
	public boolean canExecute(ICustomContext context) {
		if (context.getPictogramElements().length == 1
				&& context.getPictogramElements()[0] instanceof Shape) {
			PictogramElement element = context.getPictogramElements()[0];
			DirectEditingContext ctx = new DirectEditingContext(element,
					element.getGraphicsAlgorithm());
			IDirectEditingFeature directEditingFeature = getFeatureProvider()
					.getDirectEditingFeature(ctx);
			return directEditingFeature != null;
		} else
			return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.graphiti.features.custom.ICustomFeature#execute(org.eclipse
	 * .graphiti.features.context.ICustomContext)
	 */
	@Override
	public void execute(ICustomContext context) {
		if (context.getPictogramElements().length > 0
				&& context.getPictogramElements()[0] instanceof ContainerShape) {
			ContainerShape element = (ContainerShape) context
					.getPictogramElements()[0];
			AbstractText text = findTextInContainer(element);
			editText(element, text);
		} else if (context.getPictogramElements().length > 0
				&& context.getPictogramElements()[0].getGraphicsAlgorithm() instanceof AbstractText) {
			PictogramElement element = context.getPictogramElements()[0];
			editText(element, (AbstractText) element.getGraphicsAlgorithm());
		}
	}

	/**
	 * Enables editing of the text.
	 * 
	 * @param element The pictogram element which was double-clicked.
	 * @param text The text to be edited by the user
	 */
	private void editText(PictogramElement element, AbstractText text) {
		IDirectEditingInfo directEditingInfo = getFeatureProvider()
				.getDirectEditingInfo();
		directEditingInfo.setMainPictogramElement(element);

		directEditingInfo.setGraphicsAlgorithm(text);
		if (text != null)
			directEditingInfo.setPictogramElement(text.getPictogramElement() != null ? text.getPictogramElement() : element);

		directEditingInfo.setActive(true);
		getDiagramBehavior().refresh();
	}

	/**
	 * Finds the text in a container shape and returns it.
	 * 
	 * @param container The container shape to find the text in.
	 * @return The found abstract text, else null. 
	 */
	private AbstractText findTextInContainer(ContainerShape container) {
		for (Shape shape : container.getChildren()) {
			if (shape instanceof ContainerShape) {
				for (Shape nested : ((ContainerShape) shape).getChildren()) {
					if (nested.getGraphicsAlgorithm() instanceof AbstractText)
						return findTextInGraphicsAlgorithm(nested);
				}
			}
			if (shape.getGraphicsAlgorithm() instanceof AbstractText)
				return findTextInGraphicsAlgorithm(shape);
		}
		return findTextInGraphicsAlgorithm(container);
	}
	
	/**
	 * Searches in the graphics algorithm and the graphics algorithm children of
	 * th shape for text algorithms.
	 * 
	 * @param shape
	 *            The shape to find texts in.
	 * @return The first text that has been found.
	 */
	private AbstractText findTextInGraphicsAlgorithm(Shape shape){
		if (shape.getGraphicsAlgorithm() instanceof AbstractText)
			return (AbstractText) shape.getGraphicsAlgorithm();
		else if(shape.getGraphicsAlgorithm() != null){
			for(GraphicsAlgorithm algoChild : shape.getGraphicsAlgorithm().getGraphicsAlgorithmChildren()){
				if (algoChild instanceof AbstractText)
					return (AbstractText) algoChild;
			}
			return null;
		}
		else
			return null;
	}

}