#include "AudioSubmix.hpp"
#include "AudioVoiceEngine.hpp"
#include "AudioVoice.hpp"
#include <cstring>
#include <algorithm>

#undef min
#undef max

namespace boo
{

AudioSubmix::AudioSubmix(BaseAudioVoiceEngine& root, IAudioSubmixCallback* cb, int busId, bool mainOut)
: ListNode<AudioSubmix, BaseAudioVoiceEngine*, IAudioSubmix>(&root), m_busId(busId), m_mainOut(mainOut), m_cb(cb)
{
    if (mainOut)
        setSendLevel(m_head->m_mainSubmix.get(), 1.f, false);
}

AudioSubmix::~AudioSubmix()
{
    m_head->m_submixesDirty = true;
}

AudioSubmix*& AudioSubmix::_getHeadPtr(BaseAudioVoiceEngine* head) { return head->m_submixHead; }
std::unique_lock<std::recursive_mutex> AudioSubmix::_getHeadLock(BaseAudioVoiceEngine* head)
{ return std::unique_lock<std::recursive_mutex>{head->m_dataMutex}; }
std::unique_lock<std::recursive_mutex> AudioSubmix::destructorLock()
{ return std::unique_lock<std::recursive_mutex>{m_head->m_dataMutex}; }

bool AudioSubmix::_isDirectDependencyOf(AudioSubmix* send)
{
    return m_sendGains.find(send) != m_sendGains.cend();
}

bool AudioSubmix::_mergeC3(std::list<AudioSubmix*>& output,
                           std::vector<std::list<AudioSubmix*>>& lists)
{
    for (auto outerIt = lists.begin() ; outerIt != lists.cend() ; ++outerIt)
    {
        if (outerIt->empty())
            continue;
        AudioSubmix* smx = outerIt->front();
        bool found = false;
        for (auto innerIt = lists.begin() ; innerIt != lists.cend() ; ++innerIt)
        {
            if (innerIt->empty() || outerIt == innerIt)
                continue;
            if (smx == innerIt->front())
            {
                innerIt->pop_front();
                found = true;
            }
        }
        if (found)
        {
            outerIt->pop_front();
            output.push_back(smx);
            return true;
        }
    }
    return false;
}

std::list<AudioSubmix*> AudioSubmix::_linearizeC3()
{
    std::vector<std::list<AudioSubmix*>> lists = {{}};
    if (m_head->m_submixHead)
        for (AudioSubmix& smx : *m_head->m_submixHead)
        {
            if (&smx == this)
                continue;
            if (smx._isDirectDependencyOf(this))
                lists[0].push_back(&smx);
        }
    lists.reserve(lists[0].size() + 1);
    for (AudioSubmix* smx : lists[0])
        lists.push_back(smx->_linearizeC3());

    std::list<AudioSubmix*> ret = {this};
    while (_mergeC3(ret, lists)) {}
    return ret;
}

template <typename T>
void AudioSubmix::_zeroFill()
{
    if (_getScratch<T>().size())
        std::fill(_getScratch<T>().begin(), _getScratch<T>().end(), 0);
}

template void AudioSubmix::_zeroFill<int16_t>();
template void AudioSubmix::_zeroFill<int32_t>();
template void AudioSubmix::_zeroFill<float>();

template <typename T>
T* AudioSubmix::_getMergeBuf(size_t frames)
{
    if (_getRedirect<T>())
        return _getRedirect<T>();

    size_t sampleCount = frames * m_head->clientMixInfo().m_channelMap.m_channelCount;
    if (_getScratch<T>().size() < sampleCount)
        _getScratch<T>().resize(sampleCount);

    return _getScratch<T>().data();
}

template int16_t* AudioSubmix::_getMergeBuf<int16_t>(size_t frames);
template int32_t* AudioSubmix::_getMergeBuf<int32_t>(size_t frames);
template float* AudioSubmix::_getMergeBuf<float>(size_t frames);

template <typename T>
static inline T ClampInt(float in)
{
    if (std::is_floating_point<T>())
    {
        return in; // Allow subsequent mixing stages to work with over-saturated values
    }
    else
    {
        constexpr T MAX = std::numeric_limits<T>::max();
        constexpr T MIN = std::numeric_limits<T>::min();

        if (in < MIN)
            return MIN;
        else if (in > MAX)
            return MAX;
        else
            return in;
    }
}

template <typename T>
size_t AudioSubmix::_pumpAndMix(size_t frames)
{
    const ChannelMap& chMap = m_head->clientMixInfo().m_channelMap;
    size_t chanCount = chMap.m_channelCount;

    if (_getRedirect<T>())
    {
        if (m_cb && m_cb->canApplyEffect())
            m_cb->applyEffect(_getRedirect<T>(), frames, chMap, m_head->mixInfo().m_sampleRate);
        _getRedirect<T>() += chanCount * frames;
    }
    else
    {
        size_t sampleCount = frames * chanCount;
        if (_getScratch<T>().size() < sampleCount)
            _getScratch<T>().resize(sampleCount);
        if (m_cb && m_cb->canApplyEffect())
            m_cb->applyEffect(_getScratch<T>().data(), frames, chMap, m_head->mixInfo().m_sampleRate);

        size_t curSlewFrame = m_slewFrames;
        for (auto& smx : m_sendGains)
        {
            curSlewFrame = m_curSlewFrame;
            AudioSubmix& sm = *reinterpret_cast<AudioSubmix*>(smx.first);
            auto it = _getScratch<T>().begin();
            T* dataOut = sm._getMergeBuf<T>(frames);

            for (size_t f=0 ; f<frames ; ++f)
            {
                if (m_slewFrames && curSlewFrame < m_slewFrames)
                {
                    double t = curSlewFrame / double(m_slewFrames);
                    double omt = 1.0 - t;

                    for (unsigned c=0 ; c<chanCount ; ++c)
                    {
                        *dataOut = ClampInt<T>(*dataOut + *it * (smx.second[1] * t + smx.second[0] * omt));
                        ++it;
                        ++dataOut;
                    }

                    ++curSlewFrame;
                }
                else
                {
                    for (unsigned c=0 ; c<chanCount ; ++c)
                    {
                        *dataOut = ClampInt<T>(*dataOut + *it * smx.second[1]);
                        ++it;
                        ++dataOut;
                    }
                }
            }
        }
        m_curSlewFrame += curSlewFrame;
    }

    return frames;
}

template size_t AudioSubmix::_pumpAndMix<int16_t>(size_t frames);
template size_t AudioSubmix::_pumpAndMix<int32_t>(size_t frames);
template size_t AudioSubmix::_pumpAndMix<float>(size_t frames);

void AudioSubmix::_resetOutputSampleRate()
{
    if (m_cb)
        m_cb->resetOutputSampleRate(m_head->mixInfo().m_sampleRate);
}

void AudioSubmix::resetSendLevels()
{
    if (m_sendGains.empty())
        return;
    m_sendGains.clear();
    m_head->m_submixesDirty = true;
}

void AudioSubmix::setSendLevel(IAudioSubmix* submix, float level, bool slew)
{
    auto search = m_sendGains.find(submix);
    if (search == m_sendGains.cend())
    {
        search = m_sendGains.emplace(submix, std::array<float, 2>{1.f, 1.f}).first;
        m_head->m_submixesDirty = true;
    }

    m_slewFrames = slew ? m_head->m_5msFrames : 0;
    m_curSlewFrame = 0;

    search->second[0] = search->second[1];
    search->second[1] = level;
}

const AudioVoiceEngineMixInfo& AudioSubmix::mixInfo() const
{
    return m_head->mixInfo();
}

double AudioSubmix::getSampleRate() const
{
    return mixInfo().m_sampleRate;
}

SubmixFormat AudioSubmix::getSampleFormat() const
{
    switch (mixInfo().m_sampleFormat)
    {
    case SOXR_INT16_I:
    default:
        return SubmixFormat::Int16;
    case SOXR_INT32_I:
        return SubmixFormat::Int32;
    case SOXR_FLOAT32_I:
        return SubmixFormat::Float;
    }
}

}