/*
 * Copyright (c) 2008, Piccolo2D project, http://piccolo2d.org
 * Copyright (c) 1998-2008, University of Maryland
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this list of conditions
 * and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions
 * and the following disclaimer in the documentation and/or other materials provided with the
 * distribution.
 *
 * None of the name of the University of Maryland, the name of the Piccolo2D project, or the names of its
 * contributors may be used to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package edu.umd.cs.piccolox.activities;

import edu.umd.cs.piccolo.activities.PInterpolatingActivity;

/**
 * <b>PPathActivity</b> is the abstract base class for all path activity
 * interpolators. Path activities interpolate between multiple states over the
 * duration of the activity.
 * <p>
 * Knots are used to determine when in time the activity should move from state
 * to state. Knot values should be increasing in value from 0 to 1 inclusive.
 * This class is based on the Java 3D PathInterpolator object, see that class
 * documentation for more information on the basic concepts used in this classes
 * design.
 * </p>
 * <p>
 * See PPositionPathActivity for a concrete path activity that will animate
 * through a list of points.
 * </p>
 * 
 * @version 1.0
 * @author Jesse Grosjean
 */
public abstract class PPathActivity extends PInterpolatingActivity {

    protected float[] knots;

    public PPathActivity(long duration, long stepRate, float[] knots) {
        this(duration, stepRate, 0, PInterpolatingActivity.SOURCE_TO_DESTINATION, knots);
    }

    public PPathActivity(long duration, long stepRate, int loopCount, int mode, float[] knots) {
        super(duration, stepRate, loopCount, mode);
        setKnots(knots);
    }

    public int getKnotsLength() {
        return knots.length;
    }

    public void setKnots(float[] knots) {
        this.knots = knots;
    }

    public float[] getKnots() {
        return knots;
    }

    public void setKnot(int index, float knot) {
        knots[index] = knot;
    }

    public float getKnot(int index) {
        return knots[index];
    }

    public void setRelativeTargetValue(float zeroToOne) {
        int currentKnotIndex = 0;

        while (zeroToOne > knots[currentKnotIndex]) {
            currentKnotIndex++;
        }

        int startKnot = currentKnotIndex - 1;
        int endKnot = currentKnotIndex;

        if (startKnot < 0)
            startKnot = 0;
        if (endKnot > getKnotsLength() - 1)
            endKnot = getKnotsLength() - 1;

        float currentRange = knots[endKnot] - knots[startKnot];
        float currentPointOnRange = zeroToOne - knots[startKnot];
        float normalizedPointOnRange = currentPointOnRange;

        if (currentRange != 0) {
            normalizedPointOnRange = currentPointOnRange / currentRange;
        }

        setRelativeTargetValue(normalizedPointOnRange, startKnot, endKnot);
    }

    public abstract void setRelativeTargetValue(float zeroToOne, int startKnot, int endKnot);
}