/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
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 * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

#include "HRTFDatabase.h"

#include "HRTFElevation.h"

using namespace std;

namespace WebCore {

const int HRTFDatabase::MinElevation = -45;
const int HRTFDatabase::MaxElevation = 90;
const unsigned HRTFDatabase::RawElevationAngleSpacing = 15;
const unsigned HRTFDatabase::NumberOfRawElevations = 10; // -45 -> +90 (each 15 degrees)
const unsigned HRTFDatabase::InterpolationFactor = 1;
const unsigned HRTFDatabase::NumberOfTotalElevations = NumberOfRawElevations * InterpolationFactor;

nsReturnRef<HRTFDatabase> HRTFDatabase::create(float sampleRate)
{
    return nsReturnRef<HRTFDatabase>(new HRTFDatabase(sampleRate));
}

HRTFDatabase::HRTFDatabase(float sampleRate)
    : m_sampleRate(sampleRate)
{
    m_elevations.SetLength(NumberOfTotalElevations);

    unsigned elevationIndex = 0;
    for (int elevation = MinElevation; elevation <= MaxElevation; elevation += RawElevationAngleSpacing) {
        nsAutoRef<HRTFElevation> hrtfElevation(HRTFElevation::createBuiltin(elevation, sampleRate));
        MOZ_ASSERT(hrtfElevation.get());
        if (!hrtfElevation.get())
            return;

        m_elevations[elevationIndex] = hrtfElevation.out();
        elevationIndex += InterpolationFactor;
    }

    // Now, go back and interpolate elevations.
    if (InterpolationFactor > 1) {
        for (unsigned i = 0; i < NumberOfTotalElevations; i += InterpolationFactor) {
            unsigned j = (i + InterpolationFactor);
            if (j >= NumberOfTotalElevations)
                j = i; // for last elevation interpolate with itself

            // Create the interpolated convolution kernels and delays.
            for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {
                float x = static_cast<float>(jj) / static_cast<float>(InterpolationFactor);
                m_elevations[i + jj] = HRTFElevation::createByInterpolatingSlices(m_elevations[i].get(), m_elevations[j].get(), x, sampleRate);
                MOZ_ASSERT(m_elevations[i + jj].get());
            }
        }
    }
}

size_t HRTFDatabase::sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{
    size_t amount = aMallocSizeOf(this);
    amount += m_elevations.ShallowSizeOfExcludingThis(aMallocSizeOf);
    for (size_t i = 0; i < m_elevations.Length(); i++) {
      amount += m_elevations[i]->sizeOfIncludingThis(aMallocSizeOf);
    }

    return amount;
}

void HRTFDatabase::getKernelsFromAzimuthElevation(double azimuthBlend, unsigned azimuthIndex, double elevationAngle, HRTFKernel* &kernelL, HRTFKernel* &kernelR,
                                                  double& frameDelayL, double& frameDelayR)
{
    unsigned elevationIndex = indexFromElevationAngle(elevationAngle);
    MOZ_ASSERT(elevationIndex < m_elevations.Length() && m_elevations.Length() > 0);

    if (!m_elevations.Length()) {
        kernelL = 0;
        kernelR = 0;
        return;
    }

    if (elevationIndex > m_elevations.Length() - 1)
        elevationIndex = m_elevations.Length() - 1;

    HRTFElevation* hrtfElevation = m_elevations[elevationIndex].get();
    MOZ_ASSERT(hrtfElevation);
    if (!hrtfElevation) {
        kernelL = 0;
        kernelR = 0;
        return;
    }

    hrtfElevation->getKernelsFromAzimuth(azimuthBlend, azimuthIndex, kernelL, kernelR, frameDelayL, frameDelayR);
}

unsigned HRTFDatabase::indexFromElevationAngle(double elevationAngle)
{
    // Clamp to allowed range.
    elevationAngle = mozilla::clamped(elevationAngle,
                                      static_cast<double>(MinElevation),
                                      static_cast<double>(MaxElevation));

    unsigned elevationIndex = static_cast<int>(InterpolationFactor * (elevationAngle - MinElevation) / RawElevationAngleSpacing);
    return elevationIndex;
}

} // namespace WebCore
