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Copyright (c) 2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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****************************************************************************/

#define LOG_TAG "AudioMixerController"

#include "audio/android/AudioMixerController.h"
#include "audio/android/AudioMixer.h"
#include "audio/android/Track.h"
#include "audio/android/OpenSLHelper.h"

#include <stdlib.h>
#include <algorithm>

namespace cocos2d { namespace experimental {

AudioMixerController::AudioMixerController(int bufferSizeInFrames, int sampleRate, int channelCount)
        : _bufferSizeInFrames(bufferSizeInFrames)
        , _sampleRate(sampleRate)
        , _channelCount(channelCount)
        , _mixer(nullptr)
        , _isPaused(false)
        , _isMixingFrame(false)
{
    ALOGV("In the constructor of AudioMixerController!");

    _mixingBuffer.size = (size_t) bufferSizeInFrames * 2 * channelCount;
    // Don't use posix_memalign since it was added from API 16, it will crash on Android 2.3
    // Therefore, for a workaround, we uses memalign here.
    _mixingBuffer.buf = memalign(32, _mixingBuffer.size);
    memset(_mixingBuffer.buf, 0, _mixingBuffer.size);
}

AudioMixerController::~AudioMixerController()
{
    destroy();

    if (_mixer != nullptr)
    {
        delete _mixer;
        _mixer = nullptr;
    }

    free(_mixingBuffer.buf);
}

bool AudioMixerController::init()
{
    _mixer = new (std::nothrow) AudioMixer(_bufferSizeInFrames, _sampleRate);
    return _mixer != nullptr;
}

bool AudioMixerController::addTrack(Track* track)
{
    ALOG_ASSERT(track != nullptr, "Shouldn't pass nullptr to addTrack");
    bool ret = false;

    std::lock_guard<std::mutex> lk(_activeTracksMutex);

    auto iter = std::find(_activeTracks.begin(), _activeTracks.end(), track);
    if (iter == _activeTracks.end())
    {
        _activeTracks.push_back(track);
        ret = true;
    }

    return ret;
}

template <typename T>
static void removeItemFromVector(std::vector<T>& v, T item)
{
    auto iter = std::find(v.begin(), v.end(), item);
    if (iter != v.end())
    {
        v.erase(iter);
    }
}

void AudioMixerController::initTrack(Track* track, std::vector<Track*>& tracksToRemove)
{
    if (track->isInitialized())
        return;

    uint32_t channelMask = audio_channel_out_mask_from_count(2);
    int32_t name = _mixer->getTrackName(channelMask, AUDIO_FORMAT_PCM_16_BIT,
                                        AUDIO_SESSION_OUTPUT_MIX);
    if (name < 0)
    {
        // If we could not get the track name, it means that there're MAX_NUM_TRACKS tracks
        // So ignore the new track.
        tracksToRemove.push_back(track);
    }
    else
    {
        _mixer->setBufferProvider(name, track);
        _mixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER,
                             _mixingBuffer.buf);
        _mixer->setParameter(
                name,
                AudioMixer::TRACK,
                AudioMixer::MIXER_FORMAT,
                (void *) (uintptr_t) AUDIO_FORMAT_PCM_16_BIT);
        _mixer->setParameter(
                name,
                AudioMixer::TRACK,
                AudioMixer::FORMAT,
                (void *) (uintptr_t) AUDIO_FORMAT_PCM_16_BIT);
        _mixer->setParameter(
                name,
                AudioMixer::TRACK,
                AudioMixer::MIXER_CHANNEL_MASK,
                (void *) (uintptr_t) channelMask);
        _mixer->setParameter(
                name,
                AudioMixer::TRACK,
                AudioMixer::CHANNEL_MASK,
                (void *) (uintptr_t) channelMask);

        track->setName(name);
        _mixer->enable(name);

        std::lock_guard<std::mutex> lk(track->_volumeDirtyMutex);
        gain_minifloat_packed_t volume = track->getVolumeLR();
        float lVolume = float_from_gain(gain_minifloat_unpack_left(volume));
        float rVolume = float_from_gain(gain_minifloat_unpack_right(volume));

        _mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, &lVolume);
        _mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, &rVolume);

        track->setVolumeDirty(false);
        track->setInitialized(true);
    }
}

void AudioMixerController::mixOneFrame()
{
    _isMixingFrame = true;
    _activeTracksMutex.lock();

    auto mixStart = clockNow();

    std::vector<Track*> tracksToRemove;
    tracksToRemove.reserve(_activeTracks.size());

    // FOR TESTING BEGIN
//        Track* track = _activeTracks[0];
//
//        AudioBufferProvider::Buffer buffer;
//        buffer.frameCount = _bufferSizeInFrames;
//        status_t r = track->getNextBuffer(&buffer);
////        ALOG_ASSERT(buffer.frameCount == _mixing->size / 2, "buffer.frameCount:%d, _mixing->size/2:%d", buffer.frameCount, _mixing->size/2);
//        if (r == NO_ERROR)
//        {
//            ALOGV("getNextBuffer succeed ...");
//            memcpy(_mixing->buf, buffer.raw, _mixing->size);
//        }
//        if (buffer.raw == nullptr)
//        {
//            ALOGV("Play over ...");
//            tracksToRemove.push_back(track);
//        }
//        else
//        {
//            track->releaseBuffer(&buffer);
//        }
//
//        _mixing->state = BufferState::FULL;
//        _activeTracksMutex.unlock();
    // FOR TESTING END

    Track::State state;
    // set up the tracks.
    for (auto&& track : _activeTracks)
    {
        state = track->getState();

        if (state == Track::State::PLAYING)
        {
            initTrack(track, tracksToRemove);

            int name = track->getName();
            ALOG_ASSERT(name >= 0);

            std::lock_guard<std::mutex> lk(track->_volumeDirtyMutex);

            if (track->isVolumeDirty())
            {
                gain_minifloat_packed_t volume = track->getVolumeLR();
                float lVolume = float_from_gain(gain_minifloat_unpack_left(volume));
                float rVolume = float_from_gain(gain_minifloat_unpack_right(volume));

                ALOGV("Track (name: %d)'s volume is dirty, update volume to L: %f, R: %f", name, lVolume, rVolume);

                _mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME0, &lVolume);
                _mixer->setParameter(name, AudioMixer::VOLUME, AudioMixer::VOLUME1, &rVolume);

                track->setVolumeDirty(false);
            }
        }
        else if (state == Track::State::RESUMED)
        {
            initTrack(track, tracksToRemove);

            if (track->getPrevState() == Track::State::PAUSED)
            {
                _mixer->enable(track->getName());
                track->setState(Track::State::PLAYING);
            }
            else
            {
                ALOGW("Previous state (%d) isn't PAUSED, couldn't resume!", static_cast<int>(track->getPrevState()));
            }
        }
        else if (state == Track::State::PAUSED)
        {
            initTrack(track, tracksToRemove);

            if (track->getPrevState() == Track::State::PLAYING || track->getPrevState() == Track::State::RESUMED)
            {
                _mixer->disable(track->getName());
            }
            else
            {
                ALOGW("Previous state (%d) isn't PLAYING, couldn't pause!", static_cast<int>(track->getPrevState()));
            }
        }
        else if (state == Track::State::STOPPED)
        {
            if (track->isInitialized())
            {
                _mixer->deleteTrackName(track->getName());
            }
            else
            {
                ALOGV("Track (%p) hasn't been initialized yet!", track);
            }
            tracksToRemove.push_back(track);
        }

        if (track->isPlayOver())
        {
            if (track->isLoop())
            {
                track->reset();
            }
            else
            {
                ALOGV("Play over ...");
                _mixer->deleteTrackName(track->getName());
                tracksToRemove.push_back(track);
                track->setState(Track::State::OVER);
            }
        }
    }

    bool hasAvailableTracks = _activeTracks.size() - tracksToRemove.size() > 0;

    if (hasAvailableTracks)
    {
        ALOGV_IF(_activeTracks.size() > 8,  "More than 8 active tracks: %d", (int) _activeTracks.size());
        _mixer->process(AudioBufferProvider::kInvalidPTS);
    }
    else
    {
        ALOGV("Doesn't have enough tracks: %d, %d", (int) _activeTracks.size(), (int) tracksToRemove.size());
    }

    // Remove stopped or playover tracks for active tracks container
    for (auto&& track : tracksToRemove)
    {
        removeItemFromVector(_activeTracks, track);

        if (track != nullptr && track->onStateChanged != nullptr)
        {
            track->onStateChanged(Track::State::DESTROYED);
        }
        else
        {
            ALOGE("track (%p) was released ...", track);
        }
    }

    _activeTracksMutex.unlock();

    auto mixEnd = clockNow();
    float mixInterval = intervalInMS(mixStart, mixEnd);
    ALOGV_IF(mixInterval > 1.0f, "Mix a frame waste: %fms", mixInterval);

    _isMixingFrame = false;
}

void AudioMixerController::destroy()
{
    while (_isMixingFrame)
    {
        usleep(10);
    }
    usleep(2000); // Wait for more 2ms
}

void AudioMixerController::pause()
{
    _isPaused = true;
}

void AudioMixerController::resume()
{
    _isPaused = false;
}

bool AudioMixerController::hasPlayingTacks()
{
    std::lock_guard<std::mutex> lk (_activeTracksMutex);
    if (_activeTracks.empty())
        return false;

    for (auto&& track : _activeTracks)
    {
        Track::State state = track->getState();
        if (state == Track::State::IDLE || state == Track::State::PLAYING || state == Track::State::RESUMED)
        {
            return true;
        }
    }

    return false;
}

}} // namespace cocos2d { namespace experimental {