/*
 * Copyright (C) 2010 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:
 * 1.  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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"

#if ENABLE(WEB_AUDIO)

#include "GainNode.h"

#include "AudioBus.h"
#include "AudioNodeInput.h"
#include "AudioNodeOutput.h"
#include "AudioUtilities.h"
#include "ExceptionOr.h"
#include <wtf/TZoneMallocInlines.h>

namespace WebCore {

WTF_MAKE_TZONE_OR_ISO_ALLOCATED_IMPL(GainNode);

ExceptionOr<Ref<GainNode>> GainNode::create(BaseAudioContext& context, const GainOptions& options)
{
    auto gainNode = adoptRef(*new GainNode(context));

    auto result = gainNode->handleAudioNodeOptions(options, { 2, ChannelCountMode::Max, ChannelInterpretation::Speakers });
    if (result.hasException())
        return result.releaseException();

    gainNode->gain().setValue(options.gain);

    return gainNode;
}

GainNode::GainNode(BaseAudioContext& context)
    : AudioNode(context, NodeTypeGain)
    , m_sampleAccurateGainValues(AudioUtilities::renderQuantumSize) // FIXME: can probably share temp buffer in context
    , m_gain(AudioParam::create(context, "gain"_s, 1.0, -FLT_MAX, FLT_MAX, AutomationRate::ARate))
{
    addInput();
    addOutput(1);

    initialize();
}

void GainNode::process(size_t framesToProcess)
{
    // FIXME: for some cases there is a nice optimization to avoid processing here, and let the gain change
    // happen in the summing junction input of the AudioNode we're connected to.
    // Then we can avoid all of the following:

    AudioBus& outputBus = output(0)->bus();

    if (!isInitialized() || !input(0)->isConnected())
        outputBus.zero();
    else {
        AudioBus& inputBus = input(0)->bus();

        if (gain().hasSampleAccurateValues() && gain().automationRate() == AutomationRate::ARate) {
            // Apply sample-accurate gain scaling for precise envelopes, grain windows, etc.
            ASSERT(framesToProcess <= m_sampleAccurateGainValues.size());
            if (framesToProcess <= m_sampleAccurateGainValues.size()) {
                auto gainValues = m_sampleAccurateGainValues.span().first(framesToProcess);
                gain().calculateSampleAccurateValues(gainValues);
                outputBus.copyWithSampleAccurateGainValuesFrom(inputBus, gainValues);
            }
        } else {
            // Apply the gain with de-zippering into the output bus.
            float gain = this->gain().hasSampleAccurateValues() ? this->gain().finalValue() : this->gain().value();
            if (!gain) {
                // If the gain is 0 just zero the bus.
                outputBus.zero();
            } else
                outputBus.copyWithGainFrom(inputBus, gain);
        }
    }
}

void GainNode::processOnlyAudioParams(size_t framesToProcess)
{
    std::array<float, AudioUtilities::renderQuantumSize> values;
    ASSERT(framesToProcess <= AudioUtilities::renderQuantumSize);

    m_gain->calculateSampleAccurateValues(std::span { values }.first(framesToProcess));
}

// FIXME: this can go away when we do mixing with gain directly in summing junction of AudioNodeInput
//
// As soon as we know the channel count of our input, we can lazily initialize.
// Sometimes this may be called more than once with different channel counts, in which case we must safely
// uninitialize and then re-initialize with the new channel count.
void GainNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
{
    ASSERT(context().isAudioThread() && context().isGraphOwner());

    ASSERT(input && input == this->input(0));
    if (input != this->input(0))
        return;

    unsigned numberOfChannels = input->numberOfChannels();

    if (isInitialized() && numberOfChannels != output(0)->numberOfChannels()) {
        // We're already initialized but the channel count has changed.
        uninitialize();
    }

    if (!isInitialized()) {
        // This will propagate the channel count to any nodes connected further downstream in the graph.
        output(0)->setNumberOfChannels(numberOfChannels);
        initialize();
    }

    AudioNode::checkNumberOfChannelsForInput(input);
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)
