/*******************************************************************************
 * Copyright (c) 2000, 2005 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 API and implementation
 *******************************************************************************/
package org.eclipse.gef.examples.flow.model.commands;

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

import org.eclipse.gef.commands.Command;

import org.eclipse.gef.examples.flow.model.Activity;
import org.eclipse.gef.examples.flow.model.StructuredActivity;
import org.eclipse.gef.examples.flow.model.Transition;

/**
 * Handles the deletion of Activities.
 * @author Daniel Lee
 */
public class DeleteCommand extends Command {

private Activity child;
private StructuredActivity parent;
private int index = -1;
private List sourceConnections = new ArrayList();
private List targetConnections = new ArrayList();

private void deleteConnections(Activity a) {
	if (a instanceof StructuredActivity) {
		List children = ((StructuredActivity)a).getChildren();
		for (int i = 0; i < children.size(); i++)
			deleteConnections((Activity)children.get(i));
	}
	sourceConnections.addAll(a.getIncomingTransitions());
	for (int i = 0; i < sourceConnections.size(); i++) {
		Transition t = (Transition)sourceConnections.get(i);
		t.source.removeOutput(t);
		a.removeInput(t);
	}
	targetConnections.addAll(a.getOutgoingTransitions());
	for (int i = 0; i < targetConnections.size(); i++) {
		Transition t = (Transition)targetConnections.get(i);
		t.target.removeInput(t);
		a.removeOutput(t);
	}
}

/**
 * @see org.eclipse.gef.commands.Command#execute()
 */
public void execute() {
	primExecute();
}

/**
 * Invokes the execution of this command.
 */
protected void primExecute() {
	deleteConnections(child);
	index = parent.getChildren().indexOf(child);
	parent.removeChild(child);
}

/**
 * @see org.eclipse.gef.commands.Command#redo()
 */
public void redo() {
	primExecute();
}

private void restoreConnections() {
	for (int i = 0; i < sourceConnections.size(); i++) {
		Transition t = (Transition)sourceConnections.get(i);
		t.target.addInput(t);
		t.source.addOutput(t);
	}
	sourceConnections.clear();
	for (int i = 0; i < targetConnections.size(); i++) {
		Transition t = (Transition)targetConnections.get(i);
		t.source.addOutput(t);
		t.target.addInput(t);
	}
	targetConnections.clear();
}

/**
 * Sets the child to the passed Activity
 * @param a the child
 */
public void setChild (Activity a) {
	child = a;
}

/**
 * Sets the parent to the passed StructuredActivity
 * @param sa the parent
 */
public void setParent(StructuredActivity sa) {
	parent = sa;
}

/**
 * @see org.eclipse.gef.commands.Command#undo()
 */
public void undo() {
	parent.addChild(child, index);
	restoreConnections();
}

}