/*
 Copyright (c) 1998-2005 The Regents of the University of California
 All rights reserved.
 Permission is hereby granted, without written agreement and without
 license or royalty fees, to use, copy, modify, and distribute this
 software and its documentation for any purpose, provided that the above
 copyright notice and the following two paragraphs appear in all copies
 of this software.

 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
 SUCH DAMAGE.

 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
 PROVIDED HEREUNDER IS ON AN  BASIS, AND THE UNIVERSITY OF
 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
 ENHANCEMENTS, OR MODIFICATIONS.

 PT_COPYRIGHT_VERSION_2
 COPYRIGHTENDKEY
 */
package diva.canvas.connector;

import diva.canvas.Figure;

/**
 * A graph event that is emitted when anything
 * interesting happens inside a graph by way of a GraphModel.
 * Each graph event contains an ID, a source, and a
 * previous value for all changes and deletions,
 * the specifics of which are described on a case-by-case
 * basis below.
 *
 * @author Michael Shilman, John Reekie, Contributor: Edward A. Lee
 * @version $Id$
 * @Pt.AcceptedRating Red
 */
public class ConnectorEvent extends java.util.EventObject {
    /**
     * Signifies that a connector is dragged some distance
     */
    public static final int CONNECTOR_DRAGGED = 12;

    /**
     * Signifies that a connector end is dropped. If the connector
     * is currently snapped to a target, the target can be obtained
     * from the event as the source field.
     */
    public static final int CONNECTOR_DROPPED = 13;

    /**
     * Signifies that a connector end is snapped to
     * a possible target.
     */
    public static final int CONNECTOR_SNAPPED = 14;

    /**
     * Signifies that a connector end is unsnapped from
     * the original site that it was attached to, or
     * from a possible target.
     */
    public static final int CONNECTOR_UNSNAPPED = 15;

    /**
     * This event concerns the head end of the connector.
     *
     * @see #getEnd()
     */
    public static final int HEAD_END = 21;

    /**
     * This event concerns the tail end of the connector.
     *
     * @see #getEnd()
     */
    public static final int TAIL_END = 22;

    /**
     * This event is concerns both ends of the connector.
     *
     * @see #getEnd()
     */
    public static final int BOTH_ENDS = 23;

    /**
     * This event is concerns the midpoint of the connector.
     *
     * @see #getEnd()
     */
    public static final int MIDPOINT = 24;

    /**
     * The event ID.
     *
     * @see #getID()
     * @serial
     */
    private int _id;

    /**
     * The end this event concerns.
     *
     * @see #getEnd()
     * @serial
     */
    private int _end;

    /**
     * The target figure
     *
     * @see #getTarget()
     * @serial
     */
    private Figure _target;

    /**
     * The connector that is being operated on.
     *
     * @see #getConnector()
     * @serial
     */
    private Connector _connector;

    /**
     * Construct a ConnectorEvent with the given source, target,
     * connector, and "end" flag. The source is the layer in which
     * the connector exists, while the target is the figure that the
     * connector is snapped to or unsnapped from.
     */
    public ConnectorEvent(int id, Object source, Figure target,
            Connector connector, int end) {
        super(source);
        _target = target;
        _id = id;
        _connector = connector;
        _end = end;
    }

    /**
     * Return the connector that this event concerns.
     */
    public Connector getConnector() {
        return _connector;
    }

    /**
     * Return the end of the connector that this
     * event concerns.
     */
    public int getEnd() {
        return _end;
    }

    /**
     * Return the type id for this event.
     */
    public int getID() {
        return _id;
    }

    /**
     * Return the target that the connector is snapped to
     * or unsnapped from.
     */
    public Figure getTarget() {
        return _target;
    }

    /**
     * Return a string representation of the ID.
     */
    private String idToString() {
        switch (getID()) {
        case CONNECTOR_DRAGGED:
            return "CONNECTOR_DRAGGED";

        case CONNECTOR_DROPPED:
            return "CONNECTOR_DROPPED";

        case CONNECTOR_SNAPPED:
            return "CONNECTOR_SNAPPED";

        case CONNECTOR_UNSNAPPED:
            return "CONNECTOR_UNSNAPPED";

        default:
            return "Invalid event ID";
        }
    }

    /**
     * Return a string representation of the endpoint.
     */
    private String endToString() {
        switch (getEnd()) {
        case HEAD_END:
            return "HEAD_END";

        case TAIL_END:
            return "TAIL_END";

        case BOTH_ENDS:
            return "BOTH_ENDS";

        default:
            return "Invalid end.";
        }
    }

    public String toString() {
        return "ConnectorEvent[" + idToString() + ", " + getConnector() + ", "
                + endToString() + "]";
    }
}