/*******************************************************************************
 * Copyright (c) 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/

module dwtx.draw2d.RoutingAnimator;

import dwt.dwthelper.utils;

import dwtx.draw2d.geometry.Point;
import dwtx.draw2d.geometry.PointList;
import dwtx.draw2d.Animator;
import dwtx.draw2d.RoutingListener;
import dwtx.draw2d.IFigure;
import dwtx.draw2d.Connection;
import dwtx.draw2d.Animation;

/**
 * Animates the routing of a connection. The animator will capture the effects of the
 * connection's router, and the play back the placement of the routing, interpolating the
 * intermediate routes.
 * <P>
 * To use a routing animator, hook it as a routing listener for the connection whose
 * points are to be animated, by calling {@link
 * PolylineConnection#addRoutingListener(RoutingListener)}. An animator is active
 * only when the Animation utility is activated.
 *
 * @since 3.2
 */
public class RoutingAnimator : Animator , RoutingListener {

static const RoutingAnimator INSTANCE;
static this(){
    INSTANCE = new RoutingAnimator();
}
/**
 * Constructs a routing animator for use with one or more connections. The default
 * instance ({@link #getDefault()} can be used on any number of connections.
 *
 * @since 3.2
 */
protected this() { }

/**
 * Overridden to sync initial and final states.
 * @see Animator#playbackStarting(IFigure)
 */
public void playbackStarting(IFigure connection) {
    reconcileStates(cast(Connection)connection);
}

/**
 * Returns the current state of the connection. Currently, this is a copy of the list of
 * points. However this Object could change in future releases and should not be
 * considered API.
 * @see Animator#getCurrentState(IFigure)
 */
protected Object getCurrentState(IFigure connection) {
    return (cast(Connection)connection).getPoints().getCopy();
}

/**
 * Returns the default instance.
 * @return the default instance
 * @since 3.2
 */
public static RoutingAnimator getDefault() {
    return INSTANCE;
}

/**
 * Hooks invalidate for animation purposes.
 * @see RoutingListener#invalidate(Connection)
 */
public final void invalidate(Connection conn) {
    if (Animation.isInitialRecording())
        Animation.hookAnimator(conn, this);
}

/**
 * Plays back the interpolated state.
 * @see Animator#playback(IFigure)
 */
protected bool playback(IFigure figure) {
    Connection conn = cast(Connection) figure;

    PointList list1 = cast(PointList)Animation.getInitialState(this, conn);
    PointList list2 = cast(PointList)Animation.getFinalState(this, conn);
    if (list1 is null) {
        conn.setVisible(false);
        return true;
    }

    float progress = Animation.getProgress();
    if (list1.size() is list2.size()) {
        Point pt1 = new Point(), pt2 = new Point();
        PointList points = conn.getPoints();
        points.removeAllPoints();
        for (int i = 0; i < list1.size(); i++) {
            list1.getPoint(pt2, i);
            list2.getPoint(pt1, i);
            pt1.x = cast(int)Math.round(pt1.x * progress + (1 - progress) * pt2.x);
            pt1.y = cast(int)Math.round(pt1.y * progress + (1 - progress) * pt2.y);
            points.addPoint(pt1);
        }
        conn.setPoints(points);
    }
    return true;
}

/**
 * Hooks post routing for animation purposes.
 * @see RoutingListener#postRoute(Connection)
 */
public final void postRoute(Connection connection) {
    if (Animation.isFinalRecording())
        Animation.hookNeedsCapture(connection, this);
}

private void reconcileStates(Connection conn) {
    PointList points1 = cast(PointList)Animation.getInitialState(this, conn);
    PointList points2 = cast(PointList)Animation.getFinalState(this, conn);

    if (points1 !is null && points1.size() !is points2.size()) {
        Point p = new Point(), q = new Point();

        int size1 = points1.size() - 1;
        int size2 = points2.size() - 1;

        int i1 = size1;
        int i2 = size2;

        double current1 = 1.0;
        double current2 = 1.0;

        double prev1 = 1.0;
        double prev2 = 1.0;

        while (i1 > 0 || i2 > 0) {
            if (Math.abs(current1 - current2) < 0.1
              && i1 > 0 && i2 > 0) {
                //Both points are the same, use them and go on;
                prev1 = current1;
                prev2 = current2;
                i1--;
                i2--;
                current1 = cast(double)i1 / size1;
                current2 = cast(double)i2 / size2;
            } else if (current1 < current2) {
                //2 needs to catch up
                // current1 < current2 < prev1
                points1.getPoint(p, i1);
                points1.getPoint(q, i1 + 1);

                p.x = cast(int)(((q.x * (current2 - current1) + p.x * (prev1 - current2))
                    / (prev1 - current1)));
                p.y = cast(int)(((q.y * (current2 - current1) + p.y * (prev1 - current2))
                    / (prev1 - current1)));

                points1.insertPoint(p, i1 + 1);

                prev1 = prev2 = current2;
                i2--;
                current2 = cast(double)i2 / size2;

            } else {
                //1 needs to catch up
                // current2< current1 < prev2

                points2.getPoint(p, i2);
                points2.getPoint(q, i2 + 1);

                p.x = cast(int)(((q.x * (current1 - current2) + p.x * (prev2 - current1))
                    / (prev2 - current2)));
                p.y = cast(int)(((q.y * (current1 - current2) + p.y * (prev2 - current1))
                    / (prev2 - current2)));

                points2.insertPoint(p, i2 + 1);

                prev2 = prev1 = current1;
                i1--;
                current1 = cast(double)i1 / size1;
            }
        }
    }
}

/**
 * This callback is unused. Reserved for possible future use.
 * @see RoutingListener#remove(Connection)
 */
public final void remove(Connection connection) { }

/**
 * Hooks route to intercept routing during animation playback.
 * @see RoutingListener#route(Connection)
 */
public final bool route(Connection conn) {
    return Animation.isAnimating() && Animation.hookPlayback(conn, this);
}

/**
 * This callback is unused. Reserved for possible future use.
 * @see RoutingListener#setConstraint(Connection, Object)
 */
public final void setConstraint(Connection connection, Object constraint) { }

}