/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.anim.values;

import org.apache.batik.anim.dom.AnimationTarget;

/**
 * A number value in the animation system.
 *
 * @author <a href="mailto:cam%40mcc%2eid%2eau">Cameron McCormack</a>
 * @version $Id$
 */
public class AnimatableNumberValue extends AnimatableValue {

    /**
     * The value.
     */
    protected float value;

    /**
     * Creates a new, uninitialized AnimatableNumberValue.
     */
    protected AnimatableNumberValue(AnimationTarget target) {
        super(target);
    }
    
    /**
     * Creates a new AnimatableNumberValue.
     */
    public AnimatableNumberValue(AnimationTarget target, float v) {
        super(target);
        value = v;
    }

    /**
     * Performs interpolation to the given value.
     */
    public AnimatableValue interpolate(AnimatableValue result,
                                       AnimatableValue to,
                                       float interpolation,
                                       AnimatableValue accumulation,
                                       int multiplier) {
        AnimatableNumberValue res;
        if (result == null) {
            res = new AnimatableNumberValue(target);
        } else {
            res = (AnimatableNumberValue) result;
        }

        float v = value;
        if (to != null) {
            AnimatableNumberValue toNumber = (AnimatableNumberValue) to;
            v += interpolation * (toNumber.value - value);
        }
        if (accumulation != null) {
            AnimatableNumberValue accNumber = (AnimatableNumberValue) accumulation;
            v += multiplier * accNumber.value;
        }

        if (res.value != v) {
            res.value = v;
            res.hasChanged = true;
        }
        return res;
    }

    /**
     * Returns the number value.
     */
    public float getValue() {
        return value;
    }

    /**
     * Returns whether two values of this type can have their distance
     * computed, as needed by paced animation.
     */
    public boolean canPace() {
        return true;
    }

    /**
     * Returns the absolute distance between this value and the specified other
     * value.
     */
    public float distanceTo(AnimatableValue other) {
        AnimatableNumberValue o = (AnimatableNumberValue) other;
        return Math.abs(value - o.value);
    }

    /**
     * Returns a zero value of this AnimatableValue's type.
     */
    public AnimatableValue getZeroValue() {
        return new AnimatableNumberValue(target, 0);
    }

    /**
     * Returns the CSS text representation of the value.
     */
    public String getCssText() {
        return formatNumber(value);
    }
}
