/*
 * Moonlight|3D Copyright (C) 2006 The Moonlight|3D team
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Created on May 15, 2006
 */
package eu.moonlight3d.graph;

import com.trolltech.qt.core.QPointF;
import com.trolltech.qt.gui.QGraphicsRectItem;

/**
 * A graph model class representing a slot in a graph node. A slot is a named
 * end point for a link to another slot on another node.
 *
 * @author gregor
 */
public class Slot {
	/**
	 * An enumeration of valid slot types. Slot types may be important to
	 * the way the graph is laid out, deoending on the interpretation by
	 * the layouting algorithm that is used.
	 *
	 * @author gregor
	 */
	public enum Type {
		/**
		 * Input slot type. This slot type indicates that this slot receives
		 * from another slot through a connecting link.
		 */
		Input,
		/**
		 * Output slot type. This slot type indicates that this slot receives
		 * from another slot through a connecting link.
		 */
		Output
	}
	
	/**
	 * Referens to the node that this slot belongs to.
	 */
	private Node node;
	/**
	 * The name of this node. This should never be changed.
	 */
	private String name;
	/**
	 * The slot type
	 */
	private Type type;
	/**
	 * The link which is currently connected to this slot.
	 */
	private Link link;	
	/**
	 * The Qt GraphicsView item for this slot.
	 */
	private QGraphicsRectItem item;
	
	/**
	 * Default slot constructor. Its arguments are the node it belongs
	 * to, its name and the slot type. The slot name and slot type are
	 * immutable. The slot name must be unique in the scope of the node
	 * it belongs to
	 * 
	 * @param node the node this slot belongs to
	 * @param name the unique name of this slot.
	 * @param type the type of this slot.
	 */
	public Slot(Node node, String name, Type type) {
		this.node=node;
		this.name=name;
		this.type=type;
	}
	
	/**
	 * Get the node to which this slot belongs
	 * 
	 * @return the node that contains thsi slot
	 */
	public Node getNode() {
		return node;
	}
	
	/**
	 * Get the name of this slot.
	 * 
	 * @return the slot name
	 */
	public String getName() {
		return name;
	}
	
	/**
	 * Get the type of the slot (input or output).
	 * 
	 * @return slot type
	 */
	public Type getType() {
		return type;
	}
	
	/**
	 * Connect a link to this slot as either input or output.
	 * 
	 * @param link the link to connect
	 */
	public void setLink(Link link) {
		this.link=link;
		updateLinkEndpoint();
	}
	
	/**
	 * Get the link that is connected to this slot.
	 *  
	 * @return the connected link
	 */
	public Link getLink() {
		return link;
	}

	/**
	 * Internal method to pass a reference to the Qt Graphics View item
	 * that represents this slot.
	 * 
	 * @param item the Graphics View item that represents this slot 
	 */
	void setItem(QGraphicsRectItem item) {
		this.item=item;
	}
	
	/**
	 * Internal method to get the Qt Graphics View item that represents
	 * this slot.
	 * 
	 * @return the Graphics View item that represents the slot
	 */
	QGraphicsRectItem getItem() {
		return item;
	}

	void updateLinkEndpoint() {
		if(item==null) {
			return;
		}
		
		if(link!=null) {
			if(type==Type.Input) {
				QPointF endPoint=item.mapToScene(item.rect().left(), item.rect().y()+item.rect().height()/2);
				link.setEndPoint(endPoint.x(),endPoint.y());
			} else {
				QPointF startPoint=item.mapToScene(item.rect().right(), item.rect().y()+item.rect().height()/2);
				link.setStartPoint(startPoint.x(),startPoint.y());
			}
		}
	}
}