/*
 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 "LayoutSize.h"
#include "UnitBezier.h"
#include <wtf/CurrentTime.h>

namespace WebCore {

static RefPtr<FilterOperation> blendFunc(FilterOperation* fromOp, FilterOperation& toOp, double progress, const FloatSize& size, bool blendToPassthrough = false)
{
    if (toOp.blendingNeedsRendererSize())
        return toOp.blend(fromOp, progress, LayoutSize(size), blendToPassthrough);
    return toOp.blend(fromOp, progress, blendToPassthrough);
}

static FilterOperations applyFilterAnimation(const FilterOperations& from, const FilterOperations& to, double progress, const FloatSize& boxSize)
{
    // First frame of an animation.
    if (!progress)
        return from;

    // Last frame of an animation.
    if (progress == 1)
        return to;

    if (!from.isEmpty() && !to.isEmpty() && !from.operationsMatch(to))
        return to;

    FilterOperations result;

    size_t fromSize = from.operations().size();
    size_t toSize = to.operations().size();
    size_t size = std::max(fromSize, toSize);
    for (size_t i = 0; i < size; i++) {
        RefPtr<FilterOperation> fromOp = (i < fromSize) ? from.operations()[i].get() : nullptr;
        RefPtr<FilterOperation> toOp = (i < toSize) ? to.operations()[i].get() : nullptr;
        RefPtr<FilterOperation> blendedOp = toOp ? blendFunc(fromOp.get(), *toOp, progress, boxSize) : (fromOp ? blendFunc(nullptr, *fromOp, progress, boxSize, true) : nullptr);
        if (blendedOp)
            result.operations().append(blendedOp);
        else {
            RefPtr<FilterOperation> identityOp = PassthroughFilterOperation::create();
            if (progress > 0.5)
                result.operations().append(toOp ? toOp : identityOp);
            else
                result.operations().append(fromOp ? fromOp : identityOp);
        }
    }

    return result;
}

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

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

    const int loopCount = runningTime / duration;
    const double lastFullLoop = duration * double(loopCount);
    const double remainder = runningTime - lastFullLoop;
    // Ignore remainder when we've reached the end of animation.
    const double normalized = (loopCount == iterationCount) ? 1.0 : (remainder / duration);

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

static double normalizedAnimationValueForFillsForwards(double iterationCount, Animation::AnimationDirection direction)
{
    if (direction == Animation::AnimationDirectionNormal)
        return 1;
    if (direction == Animation::AnimationDirectionReverse)
        return 0;
    return shouldReverseAnimationValue(direction, iterationCount) ? 1 : 0;
}

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.isCubicBezierTimingFunction()) {
        auto& ctf = static_cast<const CubicBezierTimingFunction&>(timingFunction);
        return solveCubicBezierFunction(ctf.x1(), ctf.y1(), ctf.x2(), ctf.y2(), progress, duration);
    }

    if (timingFunction.isStepsTimingFunction()) {
        auto& 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 FloatSize& 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 (auto& operation : blended.operations())
            operation->blend(nullptr, progress, true)->apply(matrix, boxSize);
        return matrix;
    }

    // Animation from "-webkit-transform: none".
    if (!from.size()) {
        TransformOperations blended(to);
        for (auto& operation : blended.operations())
            operation->blend(nullptr, 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;
}

static const TimingFunction& timingFunctionForAnimationValue(const AnimationValue& animationValue, const Animation& animation)
{
    if (animationValue.timingFunction())
        return *animationValue.timingFunction();
    if (animation.timingFunction())
        return *animation.timingFunction();
    return CubicBezierTimingFunction::defaultTimingFunction();
}

TextureMapperAnimation::TextureMapperAnimation(const String& name, const KeyframeValueList& keyframes, const FloatSize& boxSize, const Animation& animation, bool listsMatch, double startTime, double pauseTime, AnimationState state)
    : m_name(name.isSafeToSendToAnotherThread() ? name : name.isolatedCopy())
    , m_keyframes(keyframes)
    , m_boxSize(boxSize)
    , m_animation(Animation::create(animation))
    , m_listsMatch(listsMatch)
    , m_startTime(startTime)
    , m_pauseTime(pauseTime)
    , m_totalRunningTime(0)
    , m_lastRefreshedTime(m_startTime)
    , m_state(state)
{
}

TextureMapperAnimation::TextureMapperAnimation(const TextureMapperAnimation& other)
    : m_name(other.m_name.isSafeToSendToAnotherThread() ? other.m_name : other.m_name.isolatedCopy())
    , m_keyframes(other.m_keyframes)
    , m_boxSize(other.m_boxSize)
    , m_animation(Animation::create(*other.m_animation))
    , m_listsMatch(other.m_listsMatch)
    , m_startTime(other.m_startTime)
    , m_pauseTime(other.m_pauseTime)
    , m_totalRunningTime(other.m_totalRunningTime)
    , m_lastRefreshedTime(other.m_lastRefreshedTime)
    , m_state(other.m_state)
{
}

void TextureMapperAnimation::apply(Client& client)
{
    if (!isActive())
        return;

    double totalRunningTime = computeTotalRunningTime();
    double normalizedValue = normalizedAnimationValue(totalRunningTime, m_animation->duration(), m_animation->direction(), m_animation->iterationCount());

    if (m_animation->iterationCount() != Animation::IterationCountInfinite && totalRunningTime >= m_animation->duration() * m_animation->iterationCount()) {
        m_state = AnimationState::Stopped;
        m_pauseTime = 0;
        if (m_animation->fillsForwards())
            normalizedValue = normalizedAnimationValueForFillsForwards(m_animation->iterationCount(), m_animation->direction());
    }

    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) {
        auto& timingFunction = timingFunctionForAnimationValue(m_keyframes.at(0), *m_animation);
        normalizedValue = applyTimingFunction(timingFunction, 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());
        auto& timingFunction = timingFunctionForAnimationValue(from, *m_animation);
        normalizedValue = applyTimingFunction(timingFunction, normalizedValue, m_animation->duration());
        applyInternal(client, from, to, normalizedValue);
        break;
    }
}

void TextureMapperAnimation::pause(double time)
{
    m_state = AnimationState::Paused;
    m_pauseTime = time;
}

void TextureMapperAnimation::resume()
{
    m_state = AnimationState::Playing;
    m_pauseTime = 0;
    m_totalRunningTime = m_pauseTime;
    m_lastRefreshedTime = monotonicallyIncreasingTime();
}

double TextureMapperAnimation::computeTotalRunningTime()
{
    if (m_state == AnimationState::Paused)
        return m_pauseTime;

    double oldLastRefreshedTime = m_lastRefreshedTime;
    m_lastRefreshedTime = monotonicallyIncreasingTime();
    m_totalRunningTime += m_lastRefreshedTime - oldLastRefreshedTime;
    return m_totalRunningTime;
}

bool TextureMapperAnimation::isActive() const
{
    return m_state != AnimationState::Stopped || m_animation->fillsForwards();
}

void TextureMapperAnimation::applyInternal(Client& client, const AnimationValue& from, const AnimationValue& to, float progress)
{
    switch (m_keyframes.property()) {
    case AnimatedPropertyOpacity:
        client.setAnimatedOpacity(applyOpacityAnimation((static_cast<const FloatAnimationValue&>(from).value()), (static_cast<const FloatAnimationValue&>(to).value()), progress));
        return;
    case AnimatedPropertyTransform:
        client.setAnimatedTransform(applyTransformAnimation(static_cast<const TransformAnimationValue&>(from).value(), static_cast<const TransformAnimationValue&>(to).value(), progress, m_boxSize, m_listsMatch));
        return;
    case AnimatedPropertyFilter:
        client.setAnimatedFilters(applyFilterAnimation(static_cast<const FilterAnimationValue&>(from).value(), static_cast<const FilterAnimationValue&>(to).value(), progress, m_boxSize));
        return;
    default:
        ASSERT_NOT_REACHED();
    }
}

void TextureMapperAnimations::add(const TextureMapperAnimation& animation)
{
    // Remove the old state if we are resuming a paused animation.
    remove(animation.name(), animation.keyframes().property());

    m_animations.append(animation);
}

void TextureMapperAnimations::remove(const String& name)
{
    m_animations.removeAllMatching([&name] (const TextureMapperAnimation& animation) {
        return animation.name() == name;
    });
}

void TextureMapperAnimations::remove(const String& name, AnimatedPropertyID property)
{
    m_animations.removeAllMatching([&name, property] (const TextureMapperAnimation& animation) {
        return animation.name() == name && animation.keyframes().property() == property;
    });
}

void TextureMapperAnimations::pause(const String& name, double offset)
{
    for (auto& animation : m_animations) {
        if (animation.name() == name)
            animation.pause(offset);
    }
}

void TextureMapperAnimations::suspend(double offset)
{
    for (auto& animation : m_animations)
        animation.pause(offset);
}

void TextureMapperAnimations::resume()
{
    for (auto& animation : m_animations)
        animation.resume();
}

void TextureMapperAnimations::apply(TextureMapperAnimation::Client& client)
{
    for (auto& animation : m_animations)
        animation.apply(client);
}

bool TextureMapperAnimations::hasActiveAnimationsOfType(AnimatedPropertyID type) const
{
    return std::any_of(m_animations.begin(), m_animations.end(),
        [&type](const TextureMapperAnimation& animation) { return animation.isActive() && animation.keyframes().property() == type; });
}

bool TextureMapperAnimations::hasRunningAnimations() const
{
    return std::any_of(m_animations.begin(), m_animations.end(),
        [](const TextureMapperAnimation& animation) { return animation.state() == TextureMapperAnimation::AnimationState::Playing; });
}

TextureMapperAnimations TextureMapperAnimations::getActiveAnimations() const
{
    TextureMapperAnimations active;
    for (auto& animation : m_animations) {
        if (animation.isActive())
            active.add(animation);
    }
    return active;
}

} // namespace WebCore