/*
 Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Library General Public
 License as published by the Free Software Foundation; either
 version 2 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Library General Public License for more details.

 You should have received a copy of the GNU Library General Public License
 along with this library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "TextureMapperAnimation.h"

#include "CurrentTime.h"
#include "UnitBezier.h"

#if USE(TEXTURE_MAPPER)
namespace WebCore {


static bool shouldReverseAnimationValue(Animation::AnimationDirection direction, int loopCount)
{
    if (((direction == Animation::AnimationDirectionAlternate) && (loopCount & 1))
        || ((direction == Animation::AnimationDirectionAlternateReverse) && !(loopCount & 1))
        || direction == Animation::AnimationDirectionReverse)
        return true;
    return false;
}

static double normalizedAnimationValue(double runningTime, double duration, Animation::AnimationDirection direction)
{
    if (!duration)
        return 0;

    const int loopCount = runningTime / duration;
    const double lastFullLoop = duration * double(loopCount);
    const double remainder = runningTime - lastFullLoop;
    const double normalized = remainder / duration;

    return shouldReverseAnimationValue(direction, loopCount) ? 1 - normalized : normalized;
}

static float applyOpacityAnimation(float fromOpacity, float toOpacity, double progress)
{
    // Optimization: special case the edge values (0 and 1).
    if (progress == 1.0)
        return toOpacity;

    if (!progress)
        return fromOpacity;

    return fromOpacity + progress * (toOpacity - fromOpacity);
}

static inline double solveEpsilon(double duration)
{
    return 1.0 / (200.0 * duration);
}

static inline double solveCubicBezierFunction(double p1x, double p1y, double p2x, double p2y, double t, double duration)
{
    return UnitBezier(p1x, p1y, p2x, p2y).solve(t, solveEpsilon(duration));
}

static inline double solveStepsFunction(int numSteps, bool stepAtStart, double t)
{
    if (stepAtStart)
        return std::min(1.0, (floor(numSteps * t) + 1) / numSteps);
    return floor(numSteps * t) / numSteps;
}

static inline float applyTimingFunction(const TimingFunction* timingFunction, float progress, double duration)
{
    if (!timingFunction)
        return progress;

    if (timingFunction->isCubicBezierTimingFunction()) {
        const CubicBezierTimingFunction* ctf = static_cast<const CubicBezierTimingFunction*>(timingFunction);
        return solveCubicBezierFunction(ctf->x1(), ctf->y1(), ctf->x2(), ctf->y2(), progress, duration);
    }

    if (timingFunction->isStepsTimingFunction()) {
        const StepsTimingFunction* stf = static_cast<const StepsTimingFunction*>(timingFunction);
        return solveStepsFunction(stf->numberOfSteps(), stf->stepAtStart(), double(progress));
    }

    return progress;
}

static TransformationMatrix applyTransformAnimation(const TransformOperations* from, const TransformOperations* to, double progress, const IntSize& boxSize, bool listsMatch)
{
    TransformationMatrix matrix;

    // First frame of an animation.
    if (!progress) {
        from->apply(boxSize, matrix);
        return matrix;
    }

    // Last frame of an animation.
    if (progress == 1) {
        to->apply(boxSize, matrix);
        return matrix;
    }

    // If we have incompatible operation lists, we blend the resulting matrices.
    if (!listsMatch) {
        TransformationMatrix fromMatrix;
        to->apply(boxSize, matrix);
        from->apply(boxSize, fromMatrix);
        matrix.blend(fromMatrix, progress);
        return matrix;
    }

    // Animation to "-webkit-transform: none".
    if (!to->size()) {
        TransformOperations blended(*from);
        for (size_t i = 0; i < blended.operations().size(); ++i)
            blended.operations()[i]->blend(0, progress, true)->apply(matrix, boxSize);
        return matrix;
    }

    // Animation from "-webkit-transform: none".
    if (!from->size()) {
        TransformOperations blended(*to);
        for (size_t i = 0; i < blended.operations().size(); ++i)
            blended.operations()[i]->blend(0, 1. - progress, true)->apply(matrix, boxSize);
        return matrix;
    }

    // Normal animation with a matching operation list.
    TransformOperations blended(*to);
    for (size_t i = 0; i < blended.operations().size(); ++i)
        blended.operations()[i]->blend(from->at(i), progress, !from->at(i))->apply(matrix, boxSize);
    return matrix;
}


TextureMapperAnimation::TextureMapperAnimation(const KeyframeValueList& keyframes, const IntSize& boxSize, const Animation* animation, double timeOffset, bool listsMatch)
    : m_keyframes(keyframes)
    , m_boxSize(boxSize)
    , m_animation(Animation::create(animation))
    , m_listsMatch(listsMatch)
    , m_startTime(WTF::currentTime() - timeOffset)
    , m_pauseTime(0)
    , m_state(PlayingState)
{
}

void TextureMapperAnimation::applyInternal(TextureMapperAnimationClient* client, const AnimationValue* from, const AnimationValue* to, float progress)
{
    switch (m_keyframes.property()) {
    case AnimatedPropertyOpacity:
        client->setOpacity(applyOpacityAnimation((static_cast<const FloatAnimationValue*>(from)->value()), (static_cast<const FloatAnimationValue*>(to)->value()), progress));
        return;
    case AnimatedPropertyWebkitTransform:
        client->setTransform(applyTransformAnimation(static_cast<const TransformAnimationValue*>(from)->value(), static_cast<const TransformAnimationValue*>(to)->value(), progress, m_boxSize, m_listsMatch));
        return;
    default:
        ASSERT_NOT_REACHED();
    }
}

bool TextureMapperAnimation::isActive() const
{
    if (state() != StoppedState)
        return true;

    return m_animation->fillsForwards();
}

bool TextureMapperAnimations::hasActiveAnimationsOfType(AnimatedPropertyID type) const
{
    HashMap<String, TextureMapperAnimation>::const_iterator end = m_animations.end();
    for (HashMap<String, TextureMapperAnimation>::const_iterator it = m_animations.begin(); it != end; ++it) {
        const TextureMapperAnimation& animation = it->second;
        if (animation.isActive() && animation.property() == type)
            return true;
    }
    return false;
}

bool TextureMapperAnimations::hasRunningAnimations() const
{
    HashMap<String, TextureMapperAnimation>::const_iterator end = m_animations.end();
    for (HashMap<String, TextureMapperAnimation>::const_iterator it = m_animations.begin(); it != end; ++it) {
        const TextureMapperAnimation& animation = it->second;
        if (animation.state() == TextureMapperAnimation::PlayingState)
            return true;
    }

    return false;
}

void TextureMapperAnimation::apply(TextureMapperAnimationClient* client)
{
    if (state() == StoppedState)
        return;

    double totalRunningTime = m_state == PausedState ? m_pauseTime : WTF::currentTime() - m_startTime;
    double normalizedValue = normalizedAnimationValue(totalRunningTime, m_animation->duration(), m_animation->direction());

    if (m_animation->iterationCount() != Animation::IterationCountInfinite && totalRunningTime >= m_animation->duration() * m_animation->iterationCount())
        setState(StoppedState);

    if (!normalizedValue) {
        applyInternal(client, m_keyframes.at(0), m_keyframes.at(1), 0);
        return;
    }

    if (normalizedValue == 1.0) {
        applyInternal(client, m_keyframes.at(m_keyframes.size() - 2), m_keyframes.at(m_keyframes.size() - 1), 1);
        return;
    }
    if (m_keyframes.size() == 2) {
        normalizedValue = applyTimingFunction(m_animation->timingFunction().get(), normalizedValue, m_animation->duration());
        applyInternal(client, m_keyframes.at(0), m_keyframes.at(1), normalizedValue);
        return;
    }

    for (size_t i = 0; i < m_keyframes.size() - 1; ++i) {
        const AnimationValue* from = m_keyframes.at(i);
        const AnimationValue* to = m_keyframes.at(i + 1);
        if (from->keyTime() > normalizedValue || to->keyTime() < normalizedValue)
            continue;

        normalizedValue = (normalizedValue - from->keyTime()) / (to->keyTime() - from->keyTime());
        normalizedValue = applyTimingFunction(from->timingFunction(), normalizedValue, m_animation->duration());
        applyInternal(client, from, to, normalizedValue);
        break;
    }
}

void TextureMapperAnimation::pause(double offset)
{
    // FIXME: should apply offset here.
    setState(PausedState);
    m_pauseTime = WTF::currentTime() - offset;
}

void TextureMapperAnimations::pause(const String& name, double offset)
{
    HashMap<String, TextureMapperAnimation>::iterator it = m_animations.find(name);
    if (it == m_animations.end())
        return;
    it->second.pause(offset);
}

void TextureMapperAnimations::apply(TextureMapperAnimationClient* client)
{
    HashMap<String, TextureMapperAnimation>::iterator end = m_animations.end();
    for (HashMap<String, TextureMapperAnimation>::iterator it = m_animations.begin(); it != end; ++it)
        it->second.apply(client);
}

}
#endif