/*
 * 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 android.animation.Keyframe.IntKeyframe;
import android.animation.Keyframe.ObjectKeyframe;
import android.graphics.Path;
import android.util.Log;

import java.util.Arrays;
import java.util.List;

This class holds a collection of Keyframe 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.
@hide
/**
 * This class holds a collection of Keyframe 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.
 * @hide
 */
public class KeyframeSet implements Keyframes {

    int mNumKeyframes;

    Keyframe mFirstKeyframe;
    Keyframe mLastKeyframe;
    TimeInterpolator mInterpolator; // only used in the 2-keyframe case
    List<Keyframe> mKeyframes; // only used when there are not 2 keyframes
    TypeEvaluator mEvaluator;


    public KeyframeSet(Keyframe... keyframes) {
        mNumKeyframes = keyframes.length;
        // immutable list
        mKeyframes = Arrays.asList(keyframes);
        mFirstKeyframe = keyframes[0];
        mLastKeyframe = keyframes[mNumKeyframes - 1];
        mInterpolator = mLastKeyframe.getInterpolator();
    }

    public List<Keyframe> getKeyframes() {
        return mKeyframes;
    }

    public static KeyframeSet ofInt(int... values) {
        int numKeyframes = values.length;
        IntKeyframe keyframes[] = new IntKeyframe[Math.max(numKeyframes,2)];
        if (numKeyframes == 1) {
            keyframes[0] = (IntKeyframe) Keyframe.ofInt(0f);
            keyframes[1] = (IntKeyframe) Keyframe.ofInt(1f, values[0]);
        } else {
            keyframes[0] = (IntKeyframe) Keyframe.ofInt(0f, values[0]);
            for (int i = 1; i < numKeyframes; ++i) {
                keyframes[i] =
                        (IntKeyframe) Keyframe.ofInt((float) i / (numKeyframes - 1), values[i]);
            }
        }
        return new IntKeyframeSet(keyframes);
    }

    public static KeyframeSet ofFloat(float... values) {
        boolean badValue = false;
        int numKeyframes = values.length;
        FloatKeyframe keyframes[] = new FloatKeyframe[Math.max(numKeyframes,2)];
        if (numKeyframes == 1) {
            keyframes[0] = (FloatKeyframe) Keyframe.ofFloat(0f);
            keyframes[1] = (FloatKeyframe) Keyframe.ofFloat(1f, values[0]);
            if (Float.isNaN(values[0])) {
                badValue = true;
            }
        } else {
            keyframes[0] = (FloatKeyframe) Keyframe.ofFloat(0f, values[0]);
            for (int i = 1; i < numKeyframes; ++i) {
                keyframes[i] =
                        (FloatKeyframe) Keyframe.ofFloat((float) i / (numKeyframes - 1), values[i]);
                if (Float.isNaN(values[i])) {
                    badValue = true;
                }
            }
        }
        if (badValue) {
            Log.w("Animator", "Bad value (NaN) in float animator");
        }
        return new FloatKeyframeSet(keyframes);
    }

    public static KeyframeSet ofKeyframe(Keyframe... keyframes) {
        // if all keyframes of same primitive type, create the appropriate KeyframeSet
        int numKeyframes = keyframes.length;
        boolean hasFloat = false;
        boolean hasInt = false;
        boolean hasOther = false;
        for (int i = 0; i < numKeyframes; ++i) {
            if (keyframes[i] instanceof FloatKeyframe) {
                hasFloat = true;
            } else if (keyframes[i] instanceof IntKeyframe) {
                hasInt = true;
            } else {
                hasOther = true;
            }
        }
        if (hasFloat && !hasInt && !hasOther) {
            FloatKeyframe floatKeyframes[] = new FloatKeyframe[numKeyframes];
            for (int i = 0; i < numKeyframes; ++i) {
                floatKeyframes[i] = (FloatKeyframe) keyframes[i];
            }
            return new FloatKeyframeSet(floatKeyframes);
        } else if (hasInt && !hasFloat && !hasOther) {
            IntKeyframe intKeyframes[] = new IntKeyframe[numKeyframes];
            for (int i = 0; i < numKeyframes; ++i) {
                intKeyframes[i] = (IntKeyframe) keyframes[i];
            }
            return new IntKeyframeSet(intKeyframes);
        } else {
            return new KeyframeSet(keyframes);
        }
    }

    public static KeyframeSet ofObject(Object... values) {
        int numKeyframes = values.length;
        ObjectKeyframe keyframes[] = new ObjectKeyframe[Math.max(numKeyframes,2)];
        if (numKeyframes == 1) {
            keyframes[0] = (ObjectKeyframe) Keyframe.ofObject(0f);
            keyframes[1] = (ObjectKeyframe) Keyframe.ofObject(1f, values[0]);
        } else {
            keyframes[0] = (ObjectKeyframe) Keyframe.ofObject(0f, values[0]);
            for (int i = 1; i < numKeyframes; ++i) {
                keyframes[i] = (ObjectKeyframe) Keyframe.ofObject((float) i / (numKeyframes - 1), values[i]);
            }
        }
        return new KeyframeSet(keyframes);
    }

    public static PathKeyframes ofPath(Path path) {
        return new PathKeyframes(path);
    }

    public static PathKeyframes ofPath(Path path, float error) {
        return new PathKeyframes(path, error);
    }

    
Sets the TypeEvaluator to be used when calculating animated values. This object
is required only for KeyframeSets that are not either IntKeyframeSet or FloatKeyframeSet,
both of which assume their own evaluator to speed up calculations with those primitive
types.
Params:
evaluator – The TypeEvaluator to be used to calculate animated values./**
     * Sets the TypeEvaluator to be used when calculating animated values. This object
     * is required only for KeyframeSets that are not either IntKeyframeSet or FloatKeyframeSet,
     * both of which assume their own evaluator to speed up calculations with those primitive
     * types.
     *
     * @param evaluator The TypeEvaluator to be used to calculate animated values.
     */
    public void setEvaluator(TypeEvaluator evaluator) {
        mEvaluator = evaluator;
    }

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

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

    
Gets the animated value, given the elapsed fraction of the animation (interpolated by the
animation's interpolator) and the evaluator used to calculate in-between values. This
function maps the input fraction to the appropriate keyframe interval and a fraction
between them and returns the interpolated value. Note that the input fraction may fall
outside the [0-1] bounds, if the animation's interpolator made that happen (e.g., a
spring interpolation that might send the fraction past 1.0). We handle this situation by
just using the two keyframes at the appropriate end when the value is outside those bounds.
Params:
fraction – The elapsed fraction of the animation
Returns:
The animated value./**
     * Gets the animated value, given the elapsed fraction of the animation (interpolated by the
     * animation's interpolator) and the evaluator used to calculate in-between values. This
     * function maps the input fraction to the appropriate keyframe interval and a fraction
     * between them and returns the interpolated value. Note that the input fraction may fall
     * outside the [0-1] bounds, if the animation's interpolator made that happen (e.g., a
     * spring interpolation that might send the fraction past 1.0). We handle this situation by
     * just using the two keyframes at the appropriate end when the value is outside those bounds.
     *
     * @param fraction The elapsed fraction of the animation
     * @return The animated value.
     */
    public Object getValue(float fraction) {
        // Special-case optimization for the common case of only two keyframes
        if (mNumKeyframes == 2) {
            if (mInterpolator != null) {
                fraction = mInterpolator.getInterpolation(fraction);
            }
            return mEvaluator.evaluate(fraction, mFirstKeyframe.getValue(),
                    mLastKeyframe.getValue());
        }
        if (fraction <= 0f) {
            final Keyframe nextKeyframe = mKeyframes.get(1);
            final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
            if (interpolator != null) {
                fraction = interpolator.getInterpolation(fraction);
            }
            final float prevFraction = mFirstKeyframe.getFraction();
            float intervalFraction = (fraction - prevFraction) /
                (nextKeyframe.getFraction() - prevFraction);
            return mEvaluator.evaluate(intervalFraction, mFirstKeyframe.getValue(),
                    nextKeyframe.getValue());
        } else if (fraction >= 1f) {
            final Keyframe prevKeyframe = mKeyframes.get(mNumKeyframes - 2);
            final TimeInterpolator interpolator = mLastKeyframe.getInterpolator();
            if (interpolator != null) {
                fraction = interpolator.getInterpolation(fraction);
            }
            final float prevFraction = prevKeyframe.getFraction();
            float intervalFraction = (fraction - prevFraction) /
                (mLastKeyframe.getFraction() - prevFraction);
            return mEvaluator.evaluate(intervalFraction, prevKeyframe.getValue(),
                    mLastKeyframe.getValue());
        }
        Keyframe prevKeyframe = mFirstKeyframe;
        for (int i = 1; i < mNumKeyframes; ++i) {
            Keyframe nextKeyframe = mKeyframes.get(i);
            if (fraction < nextKeyframe.getFraction()) {
                final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
                final float prevFraction = prevKeyframe.getFraction();
                float intervalFraction = (fraction - prevFraction) /
                    (nextKeyframe.getFraction() - prevFraction);
                // Apply interpolator on the proportional duration.
                if (interpolator != null) {
                    intervalFraction = interpolator.getInterpolation(intervalFraction);
                }
                return mEvaluator.evaluate(intervalFraction, prevKeyframe.getValue(),
                        nextKeyframe.getValue());
            }
            prevKeyframe = nextKeyframe;
        }
        // shouldn't reach here
        return mLastKeyframe.getValue();
    }

    @Override
    public String toString() {
        String returnVal = " ";
        for (int i = 0; i < mNumKeyframes; ++i) {
            returnVal += mKeyframes.get(i).getValue() + "  ";
        }
        return returnVal;
    }
}