/** 
* @file llperfstats.h
* @brief Statistics collection to support autotune and perf flaoter.
*
* $LicenseInfo:firstyear=2022&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2022, Linden Research, Inc.
* 
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
* 
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
* 
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
* 
* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
* $/LicenseInfo$
*/
#pragma once
#ifndef LL_PERFSTATS_H_INCLUDED
#define LL_PERFSTATS_H_INCLUDED

#include <atomic>
#include <chrono>
#include <array>
#include <unordered_map>
#include <mutex>
#include "lluuid.h"
#include "llfasttimer.h"
#include "llapp.h"
#include "llprofiler.h"
#include "pipeline.h"

extern U32 gFrameCount;
extern LLUUID gAgentID;
namespace LLPerfStats
{
// Note if changing these, they should correspond with the log range of the correpsonding sliders
    static constexpr U64 ART_UNLIMITED_NANOS{50000000};
    static constexpr U64 ART_MINIMUM_NANOS{100000};
    static constexpr U64 ART_MIN_ADJUST_UP_NANOS{10000};
    static constexpr U64 ART_MIN_ADJUST_DOWN_NANOS{10000}; 

    static constexpr F32 PREFERRED_DD{180};
    static constexpr U32 SMOOTHING_PERIODS{50};
    static constexpr U32 DD_STEP{10};

    static constexpr U32 TUNE_AVATARS_ONLY{0};
    static constexpr U32 TUNE_SCENE_AND_AVATARS{1};

    extern F64 cpu_hertz;

    extern std::atomic<int64_t> tunedAvatars;
    extern std::atomic<U64> renderAvatarMaxART_ns;
    extern bool belowTargetFPS;
    extern U32 lastGlobalPrefChange;
    extern std::mutex bufferToggleLock;

    enum class ObjType_t{
        OT_GENERAL=0, // Also Unknown. Used for n/a type stats such as scenery
        OT_AVATAR,
        OT_ATTACHMENT,
        OT_HUD,
        OT_COUNT
    };
    enum class StatType_t{
        RENDER_GEOMETRY=0,
        RENDER_SHADOWS,
        RENDER_HUDS,
        RENDER_UI,
        RENDER_COMBINED,
        RENDER_SWAP,
        RENDER_FRAME,
        RENDER_DISPLAY,
        RENDER_SLEEP,
        RENDER_LFS,
        RENDER_MESHREPO,
        //RENDER_FPSLIMIT,
        RENDER_FPS,
        RENDER_IDLE,
        RENDER_DONE, // toggle buffer & clearbuffer (see processUpdate for hackery)
        STATS_COUNT
    };

    struct StatsRecord
    { 
        StatType_t  statType;
        ObjType_t   objType;
        LLUUID      avID;
        LLUUID      objID;
        uint64_t    time;
        bool        isRigged;
        bool        isHUD;
    };

    struct Tunables
    {
        static constexpr U32 Nothing{0};
        static constexpr U32 NonImpostors{1};
        static constexpr U32 ReflectionDetail{2};
        static constexpr U32 FarClip{4};
        static constexpr U32 UserMinDrawDistance{8};
        static constexpr U32 UserTargetDrawDistance{16};
        static constexpr U32 UserImpostorDistance{32};
        static constexpr U32 UserImpostorDistanceTuningEnabled{64};
        static constexpr U32 UserFPSTuningStrategy{128};
        static constexpr U32 UserAutoTuneEnabled{256};
        static constexpr U32 UserTargetFPS{512};
        static constexpr U32 UserARTCutoff{1024};
        static constexpr U32 UserTargetReflections{2048};
        static constexpr U32 UserAutoTuneLock{4096};

        U32 tuningFlag{0}; // bit mask for changed settings

        // proxy variables, used to pas the new value to be set via the mainthread
        U32 nonImpostors{0}; 
        S32 reflectionDetail{0}; 
        F32 farClip{0.0}; 
        F32 userMinDrawDistance{0.0}; 
        F32 userTargetDrawDistance{0.0};
        F32 userImpostorDistance{0.0};
        bool userImpostorDistanceTuningEnabled{false};
        U32 userFPSTuningStrategy{0};
        bool userAutoTuneEnabled{false};
        bool userAutoTuneLock{true};
        U32 userTargetFPS{0};
        F32 userARTCutoffSliderValue{0};
        S32 userTargetReflections{0};

        void updateNonImposters(U32 nv){nonImpostors=nv; tuningFlag |= NonImpostors;};
        void updateReflectionDetail(S32 nv){reflectionDetail=nv; tuningFlag |= ReflectionDetail;};
        void updateFarClip(F32 nv){farClip=nv; tuningFlag |= FarClip;};
        void updateUserMinDrawDistance(F32 nv){userMinDrawDistance=nv; tuningFlag |= UserMinDrawDistance;};
        void updateUserTargetDrawDistance(F32 nv){userTargetDrawDistance=nv; tuningFlag |= UserTargetDrawDistance;};
        void updateImposterDistance(F32 nv){userImpostorDistance=nv; tuningFlag |= UserImpostorDistance;};
        void updateImposterDistanceTuningEnabled(bool nv){userImpostorDistanceTuningEnabled=nv; tuningFlag |= UserImpostorDistanceTuningEnabled;};
        void updateUserFPSTuningStrategy(U32 nv){userFPSTuningStrategy=nv; tuningFlag |= UserFPSTuningStrategy;};
        void updateTargetFps(U32 nv){userTargetFPS=nv; tuningFlag |= UserTargetFPS;};
        void updateUserARTCutoffSlider(F32 nv){userARTCutoffSliderValue=nv; tuningFlag |= UserARTCutoff;};
        void updateUserAutoTuneEnabled(bool nv){userAutoTuneEnabled=nv; tuningFlag |= UserAutoTuneEnabled;};
        void updateUserAutoTuneLock(bool nv){userAutoTuneLock=nv; tuningFlag |= UserAutoTuneLock;};
        void updateUserTargetReflections(S32 nv){userTargetReflections=nv; tuningFlag |= UserTargetReflections;};

        void resetChanges(){tuningFlag=Nothing;};
        void initialiseFromSettings();
        void updateRenderCostLimitFromSettings();
        void updateSettingsFromRenderCostLimit();
        void applyUpdates();
    };

    extern Tunables tunables;

    class StatsRecorder{
        using Queue = LLThreadSafeQueue<StatsRecord>;
    public:

        static inline StatsRecorder& getInstance()
        {
            static StatsRecorder instance;
            return instance;
        }
        static inline void setFocusAv(const LLUUID& avID){focusAv = avID;};
        static inline const LLUUID& getFocusAv(){return focusAv;};
        static inline void send(StatsRecord && upd){StatsRecorder::getInstance().q.pushFront(std::move(upd));};
        static void endFrame(){StatsRecorder::getInstance().q.pushFront(StatsRecord{StatType_t::RENDER_DONE, ObjType_t::OT_GENERAL, LLUUID::null, LLUUID::null, 0});};
        static void clearStats(){StatsRecorder::getInstance().q.pushFront(StatsRecord{StatType_t::RENDER_DONE, ObjType_t::OT_GENERAL, LLUUID::null, LLUUID::null, 1});};

        static inline void setEnabled(bool on_or_off){collectionEnabled=on_or_off;};
        static inline void enable()     { collectionEnabled=true; };
        static inline void disable()    { collectionEnabled=false; };
        static inline bool enabled()    { return collectionEnabled; };

        static inline int getReadBufferIndex() { return (writeBuffer ^ 1); };
        // static inline const StatsTypeMatrix& getCurrentStatsMatrix(){ return statsDoubleBuffer[getReadBufferIndex()];}
        static inline uint64_t get(ObjType_t otype, LLUUID id, StatType_t type)
        {
            return statsDoubleBuffer[getReadBufferIndex()][static_cast<size_t>(otype)][id][static_cast<size_t>(type)];
        }
        static inline uint64_t getSceneStat(StatType_t type)
        {
            return statsDoubleBuffer[getReadBufferIndex()][static_cast<size_t>(ObjType_t::OT_GENERAL)][LLUUID::null][static_cast<size_t>(type)];
        }

        static inline uint64_t getSum(ObjType_t otype, StatType_t type)
        {
            return sum[getReadBufferIndex()][static_cast<size_t>(otype)][static_cast<size_t>(type)];
        }
        static inline uint64_t getMax(ObjType_t otype, StatType_t type)
        {
            return max[getReadBufferIndex()][static_cast<size_t>(otype)][static_cast<size_t>(type)];
        }
        static void updateAvatarParams();
    private:
        StatsRecorder();

        static int countNearbyAvatars(S32 distance);
// StatsArray is a uint64_t for each possible statistic type.
        using StatsArray    = std::array<uint64_t, static_cast<size_t>(LLPerfStats::StatType_t::STATS_COUNT)>;
        using StatsMap      = std::unordered_map<LLUUID, StatsArray, boost::hash<LLUUID>>;
        using StatsTypeMatrix = std::array<StatsMap, static_cast<size_t>(LLPerfStats::ObjType_t::OT_COUNT)>;
        using StatsSummaryArray = std::array<StatsArray, static_cast<size_t>(LLPerfStats::ObjType_t::OT_COUNT)>;

        static std::atomic<int> writeBuffer;
        static LLUUID focusAv;
        static std::array<StatsTypeMatrix,2> statsDoubleBuffer;
        static std::array<StatsSummaryArray,2> max;
        static std::array<StatsSummaryArray,2> sum;
        static bool collectionEnabled;


        void processUpdate(const StatsRecord& upd) const
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_STATS;
            // LL_INFOS("perfstats") << "processing update:" << LL_ENDL;
            // Note: nullptr is used as the key for global stats
            #ifdef TRACY_ENABLE
            static char avstr[36];
            static char obstr[36];
            #endif

            if (upd.statType == StatType_t::RENDER_DONE && upd.objType == ObjType_t::OT_GENERAL && upd.time == 0)
            {
                // LL_INFOS("perfstats") << "End of Frame Toggle Buffer:" << gFrameCount << LL_ENDL;
                toggleBuffer();
                return;
            }
            if (upd.statType == StatType_t::RENDER_DONE && upd.objType == ObjType_t::OT_GENERAL && upd.time == 1)
            {
                // LL_INFOS("perfstats") << "New region - clear buffers:" << gFrameCount << LL_ENDL;
                clearStatsBuffers();
                return;
            }

            auto ot{upd.objType};
            auto& key{upd.objID};
            auto& avKey{upd.avID};
            auto type {upd.statType};
            auto val {upd.time};

            if (ot == ObjType_t::OT_GENERAL)
            {
                // LL_INFOS("perfstats") << "General update:" << LL_ENDL;
                doUpd(key, ot, type,val);
                return;
            }

            if (ot == ObjType_t::OT_AVATAR)
            {
                // LL_INFOS("perfstats") << "Avatar update:" << LL_ENDL;
                doUpd(avKey, ot, type, val);
                return;
            }

            if (ot == ObjType_t::OT_ATTACHMENT)
            {
                if( !upd.isHUD ) // don't include HUD cost in self.
                {
                    LL_PROFILE_ZONE_NAMED("Att as Av")
                    // For all attachments that are not rigged we add them to the avatar (for all avatars) cost.
                    doUpd(avKey, ObjType_t::OT_AVATAR, type, val);
                }
                if( avKey == focusAv )
                {
                    LL_PROFILE_ZONE_NAMED("Att as Att")
                // For attachments that are for the focusAv (self for now) we record them for the attachment/complexity view
                    if(upd.isHUD)
                    {
                        ot = ObjType_t::OT_HUD;
                    }
                    // LL_INFOS("perfstats") << "frame: " << gFrameCount << " Attachment update("<< (type==StatType_t::RENDER_GEOMETRY?"GEOMETRY":"SHADOW") << ": " << key.asString() << " = " << val << LL_ENDL;
                    doUpd(key, ot, type, val);
                }
                // else
                // {
                //     // LL_INFOS("perfstats") << "frame: " << gFrameCount << " non-self Att update("<< (type==StatType_t::RENDER_GEOMETRY?"GEOMETRY":"SHADOW") << ": " << key.asString() << " = " << val << " for av " << avKey.asString() << LL_ENDL;
                // }
            }
        }

        static inline void doUpd(const LLUUID& key, ObjType_t ot, StatType_t type, uint64_t val)
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_STATS;
            using ST = StatType_t;
            StatsMap& stm {statsDoubleBuffer[writeBuffer][static_cast<size_t>(ot)]};
            auto& thisAsset = stm[key];

            thisAsset[static_cast<size_t>(type)] += val;
            thisAsset[static_cast<size_t>(ST::RENDER_COMBINED)] += val;

            sum[writeBuffer][static_cast<size_t>(ot)][static_cast<size_t>(type)] += val;
            sum[writeBuffer][static_cast<size_t>(ot)][static_cast<size_t>(ST::RENDER_COMBINED)] += val;

            if(max[writeBuffer][static_cast<size_t>(ot)][static_cast<size_t>(type)] < thisAsset[static_cast<size_t>(type)])
            {
                max[writeBuffer][static_cast<size_t>(ot)][static_cast<size_t>(type)] = thisAsset[static_cast<size_t>(type)];
            }
            if(max[writeBuffer][static_cast<size_t>(ot)][static_cast<size_t>(ST::RENDER_COMBINED)] < thisAsset[static_cast<size_t>(ST::RENDER_COMBINED)])
            {
                max[writeBuffer][static_cast<size_t>(ot)][static_cast<size_t>(ST::RENDER_COMBINED)] = thisAsset[static_cast<size_t>(ST::RENDER_COMBINED)];
            }
        }

        static void toggleBuffer();
        static void clearStatsBuffers();

        // thread entry
        static void run()
        {
            StatsRecord upd[10];
            auto & instance {StatsRecorder::getInstance()};
            LL_PROFILER_SET_THREAD_NAME("PerfStats");

            while( enabled() && !LLApp::isExiting() )
            {
                auto count = 0;
                while (count < 10)
                {
                    if (instance.q.tryPopFor(std::chrono::milliseconds(10), upd[count]))
                    {
                        count++;
                    }
                    else
                    {
                        break;
                    }
                }
                //LL_PROFILER_THREAD_BEGIN("PerfStats");
                if(count)
                {
                    // LL_INFOS("perfstats") << "processing " << count << " updates." << LL_ENDL;
                    for(auto i =0; i < count; i++)
                    {
                        instance.processUpdate(upd[i]);
                    }
                }
                //LL_PROFILER_THREAD_END("PerfStats");
            }
        }

        Queue q;
        std::thread t;

        ~StatsRecorder() = default;
        StatsRecorder(const StatsRecorder&) = delete;
        StatsRecorder& operator=(const StatsRecorder&) = delete;

    };

    template <enum ObjType_t ObjTypeDiscriminator>
    class RecordTime
    {

    private:
        RecordTime(const RecordTime&) = delete;
        RecordTime() = delete;
        U64 start;
    public:
        StatsRecord stat;

        RecordTime( const LLUUID& av, const LLUUID& id, StatType_t type, bool isRiggedAtt=false, bool isHUDAtt=false):
                    start{LLTrace::BlockTimer::getCPUClockCount64()},
                    stat{type, ObjTypeDiscriminator, std::move(av), std::move(id), 0, isRiggedAtt, isHUDAtt}
        {
            //LL_PROFILE_ZONE_COLOR(tracy::Color::Orange);
        };

        template < ObjType_t OD = ObjTypeDiscriminator,
                   std::enable_if_t<OD == ObjType_t::OT_GENERAL> * = nullptr>
        explicit RecordTime( StatType_t type ):RecordTime<ObjTypeDiscriminator>(LLUUID::null, LLUUID::null, type )
        {
            LL_PROFILE_ZONE_SCOPED_CATEGORY_STATS;
        };

        template < ObjType_t OD = ObjTypeDiscriminator,
                   std::enable_if_t<OD == ObjType_t::OT_AVATAR> * = nullptr>
        RecordTime( const LLUUID & av, StatType_t type ):RecordTime<ObjTypeDiscriminator>(std::move(av), LLUUID::null, type)
        {
            //LL_PROFILE_ZONE_COLOR(tracy::Color::Purple);
        };

        ~RecordTime()
        { 
            if(!LLPerfStats::StatsRecorder::enabled())
            {
                return;
            }

            //LL_PROFILE_ZONE_COLOR(tracy::Color::Red);

            stat.time = LLTrace::BlockTimer::getCPUClockCount64() - start;
            StatsRecorder::send(std::move(stat));
        };
    };

    
    inline double raw_to_ns(U64 raw)    { return (static_cast<double>(raw) * 1000000000.0) / LLPerfStats::cpu_hertz; };
    inline double raw_to_us(U64 raw)    { return (static_cast<double>(raw) *    1000000.0) / LLPerfStats::cpu_hertz; };
    inline double raw_to_ms(U64 raw)    { return (static_cast<double>(raw) *       1000.0) / LLPerfStats::cpu_hertz; };

    using RecordSceneTime = RecordTime<ObjType_t::OT_GENERAL>;
    using RecordAvatarTime = RecordTime<ObjType_t::OT_AVATAR>;
    using RecordAttachmentTime = RecordTime<ObjType_t::OT_ATTACHMENT>;
    using RecordHudAttachmentTime = RecordTime<ObjType_t::OT_HUD>;
     
};// namespace LLPerfStats

// helper functions
using RATptr = std::unique_ptr<LLPerfStats::RecordAttachmentTime>;
using RSTptr = std::unique_ptr<LLPerfStats::RecordSceneTime>;

template <typename T>
static inline void trackAttachments(const T * vobj, bool isRigged, RATptr* ratPtrp)
{
    if( !vobj ){ ratPtrp->reset(); return;};
    
    const T* rootAtt{vobj};
    if (rootAtt->isAttachment())
    {
        LL_PROFILE_ZONE_SCOPED_CATEGORY_STATS;

        while( !rootAtt->isRootEdit() )
        {
            rootAtt = (T*)(rootAtt->getParent());
        }

        auto avPtr = (T*)(rootAtt->getParent()); 
        if(!avPtr){ratPtrp->reset(); return;}

        auto& av = avPtr->getID();
        auto& obj = rootAtt->getAttachmentItemID();
        if (!*ratPtrp || (*ratPtrp)->stat.objID != obj || (*ratPtrp)->stat.avID != av)
        {
            if (*ratPtrp)
            {
                // deliberately reset to ensure destruction before construction of replacement.
                ratPtrp->reset();
            };
            *ratPtrp = std::make_unique<LLPerfStats::RecordAttachmentTime>( 
                av, 
                obj,
                ( LLPipeline::sShadowRender?LLPerfStats::StatType_t::RENDER_SHADOWS : LLPerfStats::StatType_t::RENDER_GEOMETRY ), 
                isRigged, 
                rootAtt->isHUDAttachment());
        }
    }
    return;
};

#endif