/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed 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 android.animation;

import android.animation.Keyframe.FloatKeyframe;

import java.util.List;

This class holds a collection of FloatKeyframe objects and is called by ValueAnimator to calculate
values between those keyframes for a given animation. The class internal to the animation
package because it is an implementation detail of how Keyframes are stored and used.
This type-specific subclass of KeyframeSet, along with the other type-specific subclass for
int, exists to speed up the getValue() method when there is no custom
TypeEvaluator set for the animation, so that values can be calculated without autoboxing to the
Object equivalents of these primitive types.
/**
 * This class holds a collection of FloatKeyframe objects and is called by ValueAnimator to calculate
 * values between those keyframes for a given animation. The class internal to the animation
 * package because it is an implementation detail of how Keyframes are stored and used.
 *
 * <p>This type-specific subclass of KeyframeSet, along with the other type-specific subclass for
 * int, exists to speed up the getValue() method when there is no custom
 * TypeEvaluator set for the animation, so that values can be calculated without autoboxing to the
 * Object equivalents of these primitive types.</p>
 */
class FloatKeyframeSet extends KeyframeSet implements Keyframes.FloatKeyframes {
    public FloatKeyframeSet(FloatKeyframe... keyframes) {
        super(keyframes);
    }

    @Override
    public Object getValue(float fraction) {
        return getFloatValue(fraction);
    }

    @Override
    public FloatKeyframeSet clone() {
        final List<Keyframe> keyframes = mKeyframes;
        final int numKeyframes = mKeyframes.size();
        FloatKeyframe[] newKeyframes = new FloatKeyframe[numKeyframes];
        for (int i = 0; i < numKeyframes; ++i) {
            newKeyframes[i] = (FloatKeyframe) keyframes.get(i).clone();
        }
        FloatKeyframeSet newSet = new FloatKeyframeSet(newKeyframes);
        return newSet;
    }

    @Override
    public float getFloatValue(float fraction) {
        if (fraction <= 0f) {
            final FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(0);
            final FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(1);
            float prevValue = prevKeyframe.getFloatValue();
            float nextValue = nextKeyframe.getFloatValue();
            float prevFraction = prevKeyframe.getFraction();
            float nextFraction = nextKeyframe.getFraction();
            final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
            if (interpolator != null) {
                fraction = interpolator.getInterpolation(fraction);
            }
            float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
            return mEvaluator == null ?
                    prevValue + intervalFraction * (nextValue - prevValue) :
                    ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
                            floatValue();
        } else if (fraction >= 1f) {
            final FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(mNumKeyframes - 2);
            final FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(mNumKeyframes - 1);
            float prevValue = prevKeyframe.getFloatValue();
            float nextValue = nextKeyframe.getFloatValue();
            float prevFraction = prevKeyframe.getFraction();
            float nextFraction = nextKeyframe.getFraction();
            final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
            if (interpolator != null) {
                fraction = interpolator.getInterpolation(fraction);
            }
            float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
            return mEvaluator == null ?
                    prevValue + intervalFraction * (nextValue - prevValue) :
                    ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
                            floatValue();
        }
        FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(0);
        for (int i = 1; i < mNumKeyframes; ++i) {
            FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(i);
            if (fraction < nextKeyframe.getFraction()) {
                final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
                float intervalFraction = (fraction - prevKeyframe.getFraction()) /
                    (nextKeyframe.getFraction() - prevKeyframe.getFraction());
                float prevValue = prevKeyframe.getFloatValue();
                float nextValue = nextKeyframe.getFloatValue();
                // Apply interpolator on the proportional duration.
                if (interpolator != null) {
                    intervalFraction = interpolator.getInterpolation(intervalFraction);
                }
                return mEvaluator == null ?
                        prevValue + intervalFraction * (nextValue - prevValue) :
                        ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
                            floatValue();
            }
            prevKeyframe = nextKeyframe;
        }
        // shouldn't get here
        return ((Number)mKeyframes.get(mNumKeyframes - 1).getValue()).floatValue();
    }

    @Override
    public Class getType() {
        return Float.class;
    }
}