/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "core/animation/AnimatableRepeatable.h"

namespace {

size_t greatestCommonDivisor(size_t a, size_t b)
{
    return b ? greatestCommonDivisor(b, a % b) : a;
}

size_t lowestCommonMultiple(size_t a, size_t b)
{
    ASSERT(a && b);
    return a / greatestCommonDivisor(a, b) * b;
}

} // namespace

namespace WebCore {

bool AnimatableRepeatable::usesDefaultInterpolationWith(const AnimatableValue* value) const
{
    const WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> >& fromValues = m_values;
    const WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> >& toValues = toAnimatableRepeatable(value)->m_values;
    ASSERT(!fromValues.isEmpty() && !toValues.isEmpty());
    size_t size = lowestCommonMultiple(fromValues.size(), toValues.size());
    for (size_t i = 0; i < size; ++i) {
        const AnimatableValue* from = fromValues[i % fromValues.size()].get();
        const AnimatableValue* to = toValues[i % toValues.size()].get();
        // Spec: If a pair of values cannot be interpolated, then the lists are not interpolable.
        if (AnimatableValue::usesDefaultInterpolation(from, to))
            return true;
    }
    return false;
}

bool AnimatableRepeatable::interpolateLists(const WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> >& fromValues, const WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> >& toValues, double fraction, WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> >& interpolatedValues)
{
    // Interpolation behaviour spec: http://www.w3.org/TR/css3-transitions/#animtype-repeatable-list
    ASSERT(interpolatedValues.isEmpty());
    ASSERT(!fromValues.isEmpty() && !toValues.isEmpty());
    size_t size = lowestCommonMultiple(fromValues.size(), toValues.size());
    for (size_t i = 0; i < size; ++i) {
        const AnimatableValue* from = fromValues[i % fromValues.size()].get();
        const AnimatableValue* to = toValues[i % toValues.size()].get();
        // Spec: If a pair of values cannot be interpolated, then the lists are not interpolable.
        if (AnimatableValue::usesDefaultInterpolation(from, to))
            return false;
        interpolatedValues.append(interpolate(from, to, fraction));
    }
    return true;
}

PassRefPtrWillBeRawPtr<AnimatableValue> AnimatableRepeatable::interpolateTo(const AnimatableValue* value, double fraction) const
{
    WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> > interpolatedValues;
    bool success = interpolateLists(m_values, toAnimatableRepeatable(value)->m_values, fraction, interpolatedValues);
    if (success)
        return create(interpolatedValues);
    return defaultInterpolateTo(this, value, fraction);
}

bool AnimatableRepeatable::equalTo(const AnimatableValue* value) const
{
    const WillBeHeapVector<RefPtrWillBeMember<AnimatableValue> >& otherValues = toAnimatableRepeatable(value)->m_values;
    if (m_values.size() != otherValues.size())
        return false;
    for (size_t i = 0; i < m_values.size(); ++i) {
        if (!m_values[i]->equals(otherValues[i].get()))
            return false;
    }
    return true;
}

void AnimatableRepeatable::trace(Visitor* visitor)
{
    visitor->trace(m_values);
}

} // namespace WebCore