#include "config.h"

#include "context.h"

#include <algorithm>
#include <functional>
#include <limits>
#include <numeric>
#include <stddef.h>
#include <stdexcept>

#include "AL/efx.h"

#include "al/auxeffectslot.h"
#include "al/source.h"
#include "al/effect.h"
#include "al/event.h"
#include "al/listener.h"
#include "albit.h"
#include "alc/alu.h"
#include "core/async_event.h"
#include "core/device.h"
#include "core/logging.h"
#include "core/voice.h"
#include "core/voice_change.h"
#include "device.h"
#include "effectslot.h"
#include "ringbuffer.h"
#include "vecmat.h"


namespace {

using namespace std::placeholders;

using voidp = void*;

/* Default context extensions */
constexpr ALchar alExtList[] =
    "AL_EXT_ALAW "
    "AL_EXT_BFORMAT "
    "AL_EXT_DOUBLE "
    "AL_EXT_EXPONENT_DISTANCE "
    "AL_EXT_FLOAT32 "
    "AL_EXT_IMA4 "
    "AL_EXT_LINEAR_DISTANCE "
    "AL_EXT_MCFORMATS "
    "AL_EXT_MULAW "
    "AL_EXT_MULAW_BFORMAT "
    "AL_EXT_MULAW_MCFORMATS "
    "AL_EXT_OFFSET "
    "AL_EXT_source_distance_model "
    "AL_EXT_SOURCE_RADIUS "
    "AL_EXT_STEREO_ANGLES "
    "AL_LOKI_quadriphonic "
    "AL_SOFT_bformat_ex "
    "AL_SOFTX_bformat_hoa "
    "AL_SOFT_block_alignment "
    "AL_SOFTX_callback_buffer "
    "AL_SOFTX_convolution_reverb "
    "AL_SOFT_deferred_updates "
    "AL_SOFT_direct_channels "
    "AL_SOFT_direct_channels_remix "
    "AL_SOFT_effect_target "
    "AL_SOFT_events "
    "AL_SOFTX_filter_gain_ex "
    "AL_SOFT_gain_clamp_ex "
    "AL_SOFTX_hold_on_disconnect "
    "AL_SOFT_loop_points "
    "AL_SOFTX_map_buffer "
    "AL_SOFT_MSADPCM "
    "AL_SOFT_source_latency "
    "AL_SOFT_source_length "
    "AL_SOFT_source_resampler "
    "AL_SOFT_source_spatialize "
    "AL_SOFTX_UHJ";

} // namespace


std::atomic<ALCcontext*> ALCcontext::sGlobalContext{nullptr};

thread_local ALCcontext *ALCcontext::sLocalContext{nullptr};
ALCcontext::ThreadCtx::~ThreadCtx()
{
    if(ALCcontext *ctx{ALCcontext::sLocalContext})
    {
        const bool result{ctx->releaseIfNoDelete()};
        ERR("Context %p current for thread being destroyed%s!\n", voidp{ctx},
            result ? "" : ", leak detected");
    }
}
thread_local ALCcontext::ThreadCtx ALCcontext::sThreadContext;

ALeffect ALCcontext::sDefaultEffect;


ContextBase::ContextBase(DeviceBase *device) : mDevice{device}
{ }

ContextBase::~ContextBase()
{
    size_t count{0};
    ContextProps *cprops{mParams.ContextUpdate.exchange(nullptr, std::memory_order_relaxed)};
    if(cprops)
    {
        ++count;
        delete cprops;
    }
    cprops = mFreeContextProps.exchange(nullptr, std::memory_order_acquire);
    while(cprops)
    {
        std::unique_ptr<ContextProps> old{cprops};
        cprops = old->next.load(std::memory_order_relaxed);
        ++count;
    }
    TRACE("Freed %zu context property object%s\n", count, (count==1)?"":"s");

    count = 0;
    EffectSlotProps *eprops{mFreeEffectslotProps.exchange(nullptr, std::memory_order_acquire)};
    while(eprops)
    {
        std::unique_ptr<EffectSlotProps> old{eprops};
        eprops = old->next.load(std::memory_order_relaxed);
        ++count;
    }
    TRACE("Freed %zu AuxiliaryEffectSlot property object%s\n", count, (count==1)?"":"s");

    if(EffectSlotArray *curarray{mActiveAuxSlots.exchange(nullptr, std::memory_order_relaxed)})
    {
        al::destroy_n(curarray->end(), curarray->size());
        delete curarray;
    }

    count = 0;
    VoicePropsItem *vprops{mFreeVoiceProps.exchange(nullptr, std::memory_order_acquire)};
    while(vprops)
    {
        std::unique_ptr<VoicePropsItem> old{vprops};
        vprops = old->next.load(std::memory_order_relaxed);
        ++count;
    }
    TRACE("Freed %zu voice property object%s\n", count, (count==1)?"":"s");

    delete mVoices.exchange(nullptr, std::memory_order_relaxed);

    count = 0;
    ListenerProps *lprops{mParams.ListenerUpdate.exchange(nullptr, std::memory_order_relaxed)};
    if(lprops)
    {
        ++count;
        delete lprops;
    }
    lprops = mFreeListenerProps.exchange(nullptr, std::memory_order_acquire);
    while(lprops)
    {
        std::unique_ptr<ListenerProps> old{lprops};
        lprops = old->next.load(std::memory_order_relaxed);
        ++count;
    }
    TRACE("Freed %zu listener property object%s\n", count, (count==1)?"":"s");

    if(mAsyncEvents)
    {
        count = 0;
        auto evt_vec = mAsyncEvents->getReadVector();
        if(evt_vec.first.len > 0)
        {
            al::destroy_n(reinterpret_cast<AsyncEvent*>(evt_vec.first.buf), evt_vec.first.len);
            count += evt_vec.first.len;
        }
        if(evt_vec.second.len > 0)
        {
            al::destroy_n(reinterpret_cast<AsyncEvent*>(evt_vec.second.buf), evt_vec.second.len);
            count += evt_vec.second.len;
        }
        if(count > 0)
            TRACE("Destructed %zu orphaned event%s\n", count, (count==1)?"":"s");
        mAsyncEvents->readAdvance(count);
    }
}

void ContextBase::allocVoiceChanges(size_t addcount)
{
    constexpr size_t clustersize{128};
    /* Convert element count to cluster count. */
    addcount = (addcount+(clustersize-1)) / clustersize;
    while(addcount)
    {
        VoiceChangeCluster cluster{std::make_unique<VoiceChange[]>(clustersize)};
        for(size_t i{1};i < clustersize;++i)
            cluster[i-1].mNext.store(std::addressof(cluster[i]), std::memory_order_relaxed);
        cluster[clustersize-1].mNext.store(mVoiceChangeTail, std::memory_order_relaxed);
        mVoiceChangeClusters.emplace_back(std::move(cluster));
        mVoiceChangeTail = mVoiceChangeClusters.back().get();
        --addcount;
    }
}

void ContextBase::allocVoices(size_t addcount)
{
    constexpr size_t clustersize{32};
    /* Convert element count to cluster count. */
    addcount = (addcount+(clustersize-1)) / clustersize;

    if(addcount >= std::numeric_limits<int>::max()/clustersize - mVoiceClusters.size())
        throw std::runtime_error{"Allocating too many voices"};
    const size_t totalcount{(mVoiceClusters.size()+addcount) * clustersize};
    TRACE("Increasing allocated voices to %zu\n", totalcount);

    auto newarray = VoiceArray::Create(totalcount);
    while(addcount)
    {
        mVoiceClusters.emplace_back(std::make_unique<Voice[]>(clustersize));
        --addcount;
    }

    auto voice_iter = newarray->begin();
    for(VoiceCluster &cluster : mVoiceClusters)
    {
        for(size_t i{0};i < clustersize;++i)
            *(voice_iter++) = &cluster[i];
    }

    if(auto *oldvoices = mVoices.exchange(newarray.release(), std::memory_order_acq_rel))
    {
        mDevice->waitForMix();
        delete oldvoices;
    }
}


ALCcontext::ALCcontext(al::intrusive_ptr<ALCdevice> device)
  : ContextBase{device.get()}, mALDevice{std::move(device)}
{
    mPropsDirty.test_and_clear(std::memory_order_relaxed);
}

ALCcontext::~ALCcontext()
{
    TRACE("Freeing context %p\n", voidp{this});

    size_t count{std::accumulate(mSourceList.cbegin(), mSourceList.cend(), size_t{0u},
        [](size_t cur, const SourceSubList &sublist) noexcept -> size_t
        { return cur + static_cast<uint>(al::popcount(~sublist.FreeMask)); })};
    if(count > 0)
        WARN("%zu Source%s not deleted\n", count, (count==1)?"":"s");
    mSourceList.clear();
    mNumSources = 0;

    mDefaultSlot = nullptr;
    count = std::accumulate(mEffectSlotList.cbegin(), mEffectSlotList.cend(), size_t{0u},
        [](size_t cur, const EffectSlotSubList &sublist) noexcept -> size_t
        { return cur + static_cast<uint>(al::popcount(~sublist.FreeMask)); });
    if(count > 0)
        WARN("%zu AuxiliaryEffectSlot%s not deleted\n", count, (count==1)?"":"s");
    mEffectSlotList.clear();
    mNumEffectSlots = 0;
}

void ALCcontext::init()
{
    if(sDefaultEffect.type != AL_EFFECT_NULL && mDevice->Type == DeviceType::Playback)
    {
        mDefaultSlot = std::make_unique<ALeffectslot>();
        aluInitEffectPanning(&mDefaultSlot->mSlot, this);
    }

    EffectSlotArray *auxslots;
    if(!mDefaultSlot)
        auxslots = EffectSlot::CreatePtrArray(0);
    else
    {
        auxslots = EffectSlot::CreatePtrArray(1);
        (*auxslots)[0] = &mDefaultSlot->mSlot;
        mDefaultSlot->mState = SlotState::Playing;
    }
    mActiveAuxSlots.store(auxslots, std::memory_order_relaxed);

    allocVoiceChanges(1);
    {
        VoiceChange *cur{mVoiceChangeTail};
        while(VoiceChange *next{cur->mNext.load(std::memory_order_relaxed)})
            cur = next;
        mCurrentVoiceChange.store(cur, std::memory_order_relaxed);
    }

    mExtensionList = alExtList;


    mParams.Matrix = alu::Matrix::Identity();
    mParams.Velocity = alu::Vector{};
    mParams.Gain = mListener.Gain;
    mParams.MetersPerUnit = mListener.mMetersPerUnit;
    mParams.DopplerFactor = mDopplerFactor;
    mParams.SpeedOfSound = mSpeedOfSound * mDopplerVelocity;
    mParams.SourceDistanceModel = mSourceDistanceModel;
    mParams.mDistanceModel = mDistanceModel;


    mAsyncEvents = RingBuffer::Create(511, sizeof(AsyncEvent), false);
    StartEventThrd(this);


    allocVoices(256);
    mActiveVoiceCount.store(64, std::memory_order_relaxed);
}

bool ALCcontext::deinit()
{
    if(sLocalContext == this)
    {
        WARN("%p released while current on thread\n", voidp{this});
        sThreadContext.set(nullptr);
        release();
    }

    ALCcontext *origctx{this};
    if(sGlobalContext.compare_exchange_strong(origctx, nullptr))
        release();

    bool ret{};
    /* First make sure this context exists in the device's list. */
    auto *oldarray = mDevice->mContexts.load(std::memory_order_acquire);
    if(auto toremove = static_cast<size_t>(std::count(oldarray->begin(), oldarray->end(), this)))
    {
        using ContextArray = al::FlexArray<ContextBase*>;
        auto alloc_ctx_array = [](const size_t count) -> ContextArray*
        {
            if(count == 0) return &DeviceBase::sEmptyContextArray;
            return ContextArray::Create(count).release();
        };
        auto *newarray = alloc_ctx_array(oldarray->size() - toremove);

        /* Copy the current/old context handles to the new array, excluding the
         * given context.
         */
        std::copy_if(oldarray->begin(), oldarray->end(), newarray->begin(),
            std::bind(std::not_equal_to<>{}, _1, this));

        /* Store the new context array in the device. Wait for any current mix
         * to finish before deleting the old array.
         */
        mDevice->mContexts.store(newarray);
        if(oldarray != &DeviceBase::sEmptyContextArray)
        {
            mDevice->waitForMix();
            delete oldarray;
        }

        ret = !newarray->empty();
    }
    else
        ret = !oldarray->empty();

    StopEventThrd(this);

    return ret;
}

void ALCcontext::processUpdates()
{
    std::lock_guard<std::mutex> _{mPropLock};
    if(mDeferUpdates.exchange(false, std::memory_order_acq_rel))
    {
        /* Tell the mixer to stop applying updates, then wait for any active
         * updating to finish, before providing updates.
         */
        mHoldUpdates.store(true, std::memory_order_release);
        while((mUpdateCount.load(std::memory_order_acquire)&1) != 0) {
            /* busy-wait */
        }

        if(mPropsDirty.test_and_clear(std::memory_order_acq_rel))
            UpdateContextProps(this);
        if(mListener.mPropsDirty.test_and_clear(std::memory_order_acq_rel))
            UpdateListenerProps(this);
        UpdateAllEffectSlotProps(this);
        UpdateAllSourceProps(this);

        /* Now with all updates declared, let the mixer continue applying them
         * so they all happen at once.
         */
        mHoldUpdates.store(false, std::memory_order_release);
    }
}