/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Loop.NT.cpp
    Date: 2021-10-1
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "Loop.NT.hpp"
#include "ILoopSourceEx.hpp"
#include "LSWin32.NT.hpp"

#define MAXIMUM_WAIT_OBJECTS_ (MAXIMUM_WAIT_OBJECTS - 1) 

namespace Aurora::IO::Loop
{
    extern AuRWRenterableLock gWaitForMultipleALLLock;

    void ResetLoopSourceFalseAlarm(const AuSPtr<Loop::ILoopSource> &pLoopSource);

    AuList<AuSPtr<ILoopSource>> WaitMultipleOrObjects(const AuList<AuSPtr<ILoopSource>> &objects, bool bAlert, bool bBreakAPCs, bool bZeroTick, AuUInt32 dwTimeoutReq, bool bAllowOthers, bool &bTooMany)
    {
        bool                        bIsWinLoop;
        AuSPtr<ILoopSourceEx>       loopSourceExs[MAXIMUM_WAIT_OBJECTS_];
        HANDLE                      handleArray[MAXIMUM_WAIT_OBJECTS_];
        AuUInt32                    uCounterHandle, uCounterFD;
        AuSPtr<ILoopSource>         pMsgSource;
        AuList<AuSPtr<ILoopSource>> triggered;

        bIsWinLoop     = false;
        uCounterHandle = 0;
        uCounterFD     = 0;

        try
        {
            triggered.reserve(objects.size());
        }
        catch (...)
        {
            return {};
        }
        
        for (const auto &source : objects)
        {
            if (!source)
            {
                continue;
            }

            if (source->GetType() == ELoopSource::eSourceWin32)
            {
                bIsWinLoop = true;
                pMsgSource = source;
                continue;
            }

            if (auto extended = AuDynamicCast<ILoopSourceEx>(source))
            {
                {
                    auto uNewIndex = uCounterHandle++;
                    if (uNewIndex == MAXIMUM_WAIT_OBJECTS_)
                    {
                        bTooMany = true;
                        return {};
                    }
                    loopSourceExs[uNewIndex] = extended;
                }

                if (extended->Singular())
                {
                    auto uNewIndex = uCounterFD++;
                    if (uNewIndex == MAXIMUM_WAIT_OBJECTS_)
                    {
                        bTooMany = true;
                        return {};
                    }
                    handleArray[uNewIndex] = reinterpret_cast<HANDLE>(extended->GetHandle());
                }
                else
                {
                    for (const auto &handle : extended->GetHandles())
                    {
                        auto uNewIndex = uCounterFD++;
                        if (uNewIndex == MAXIMUM_WAIT_OBJECTS_)
                        {
                            bTooMany = true;
                            return {};
                        }
                        handleArray[uNewIndex] = reinterpret_cast<HANDLE>(extended->GetHandle());
                    }
                }
            }
        }

        for (AU_ITERATE_N(i, uCounterHandle))
        {
            loopSourceExs[i]->OnPresleep();
        }

        AuUInt32 uTimeout {};
        if (!bZeroTick)
        {
            uTimeout = dwTimeoutReq ?
                dwTimeoutReq :
                INFINITE;
        }

        DWORD ret;
        if (bIsWinLoop &&
            pMsgWaitForMultipleObjectsEx)
        {
            ret = pMsgWaitForMultipleObjectsEx(uCounterFD, handleArray, uTimeout, QS_ALLPOSTMESSAGE | QS_ALLINPUT, MWMO_INPUTAVAILABLE | (bAlert ? MWMO_ALERTABLE : 0));
        }
        else
        {
            ret = ::WaitForMultipleObjectsEx(uCounterFD, handleArray, false, uTimeout, bAlert);
        }

        bool error = ((ret == WAIT_TIMEOUT) ||
                      (ret == WAIT_IO_COMPLETION) ||
                      (ret == WAIT_FAILED));

        bool isPump = WAIT_OBJECT_0 + uCounterFD == ret;

        AuUInt firstTriggered {};
        if (!error)
        {
            if (!isPump)
            {
                firstTriggered = reinterpret_cast<AuUInt>(handleArray[ret - WAIT_OBJECT_0]);
            }
        }

        if (isPump)
        {
            // msg loop queue for trigger 
            AuTryInsert(triggered, pMsgSource);

            if (!bAllowOthers)
            {
                error = true;
            }
        }

        for (AU_ITERATE_N(i, uCounterHandle))
        {
            auto &pSource = loopSourceExs[i];

            if (!error)
            {
                AuUInt lastHandle {};
                bool wasTriggered {};

                if (pSource->Singular())
                {
                    auto handle = pSource->GetHandle();
                    if ((firstTriggered == handle) ||
                        (bAllowOthers && WaitForSingleObject(reinterpret_cast<HANDLE>(handle), 0) == WAIT_OBJECT_0))
                    {
                        lastHandle = handle;
                        wasTriggered = true;
                    }
                }
                else
                {
                    for (const auto &handle : pSource->GetHandles())
                    {
                        if ((firstTriggered == handle) ||
                            (bAllowOthers && WaitForSingleObject(reinterpret_cast<HANDLE>(handle), 0) == WAIT_OBJECT_0))
                        {
                            lastHandle = handle;
                            wasTriggered = true;
                            break;
                        }
                    }
                }

                // notify the loopsource of ex, only signal once we've filtered the kernel signal
                if (wasTriggered && pSource->OnTrigger(lastHandle))
                {
                    // pog
                    AuTryInsert(triggered, pSource);
                }
            }

            pSource->OnFinishSleep();
        }

        return AuMove(triggered);
    }

    bool WaitMultipleAndObjects_(const AuList<AuSPtr<ILoopSource>> &objects, bool bAlert, bool bBreakAPCs, bool bZeroTick, AuUInt64 qwTimeoutAbs, bool &bTooMany, bool &bTimeout)
    {
        bool                        bIsWinLoop;
        bool                        bRet;
        AuSPtr<ILoopSourceEx>       loopSourceExs[MAXIMUM_WAIT_OBJECTS_];
        HANDLE                      handleArray[MAXIMUM_WAIT_OBJECTS_];
        AuUInt32                    uCounterHandle, uCounterFD;
        AuSPtr<ILoopSource>         pMsgSource;

        bIsWinLoop     = false;
        uCounterHandle = 0;
        uCounterFD     = 0;
        bRet           = true;

        for (const auto &source : objects)
        {
            if (!source)
            {
                continue;
            }

            if (source->GetType() == ELoopSource::eSourceWin32)
            {
                bIsWinLoop = true;
                pMsgSource = source;
                continue;
            }

            if (auto extended = AuDynamicCast<ILoopSourceEx>(source))
            {
                {
                    auto uNewIndex = uCounterHandle++;
                    if (uNewIndex == MAXIMUM_WAIT_OBJECTS_)
                    {
                        bTooMany = true;
                        return {};
                    }
                    loopSourceExs[uNewIndex] = extended;
                }

                if (extended->Singular())
                {
                    auto uNewIndex = uCounterFD++;
                    if (uNewIndex == MAXIMUM_WAIT_OBJECTS_)
                    {
                        bTooMany = true;
                        return {};
                    }
                    handleArray[uNewIndex] = reinterpret_cast<HANDLE>(extended->GetHandle());
                }
                else
                {
                    for (const auto &handle : extended->GetHandles())
                    {
                        auto uNewIndex = uCounterFD++;
                        if (uNewIndex == MAXIMUM_WAIT_OBJECTS_)
                        {
                            bTooMany = true;
                            return {};
                        }
                        handleArray[uNewIndex] = reinterpret_cast<HANDLE>(extended->GetHandle());
                    }
                }
            }
        }

        for (AU_ITERATE_N(i, uCounterHandle))
        {
            loopSourceExs[i]->OnPresleep();
        }

        DWORD ret;
        do
        {
            AuUInt32 uTimeout;

            if (bZeroTick)
            {
                uTimeout = 0;
            }
            else if (qwTimeoutAbs)
            {
                auto uNow = AuTime::SteadyClockNS();
                if (uNow >= qwTimeoutAbs)
                {
                    uTimeout = 0;
                }
                else
                {
                    uTimeout = AuNSToMS<AuUInt32>(qwTimeoutAbs - uNow);
                }
            }
            else
            {
                uTimeout = -1;
            }

            if (bIsWinLoop &&
                pMsgWaitForMultipleObjectsEx)
            {
                ret = pMsgWaitForMultipleObjectsEx(uCounterFD, handleArray, uTimeout, QS_ALLPOSTMESSAGE | QS_ALLINPUT, MWMO_INPUTAVAILABLE | MWMO_WAITALL | (bAlert ? MWMO_ALERTABLE : 0));
            }
            else
            {
                ret = ::WaitForMultipleObjectsEx(uCounterFD, handleArray, TRUE, uTimeout, bAlert);
            }
        }
        while (!bBreakAPCs && ret == WAIT_IO_COMPLETION);

        bool error = ((ret == WAIT_TIMEOUT) ||
                      (ret == WAIT_IO_COMPLETION) ||
                      (ret == WAIT_FAILED));

        if (WAIT_OBJECT_0 + uCounterFD == ret)
        {
            bTimeout = false;
            bRet = false;
        }
        else if (error)
        {
            bTimeout = ret == WAIT_TIMEOUT;
            bRet = false;
        }

        {
            AU_LOCK_GLOBAL_GUARD(gWaitForMultipleALLLock->AsWritable());

            for (AU_ITERATE_N(i, uCounterHandle))
            {
                auto &pSource = loopSourceExs[i];

                if (bRet)
                {
                    AuUInt lastHandle {};
                    bool wasTriggered {};

                    if (pSource->Singular())
                    {
                        auto handle = pSource->GetHandle();
                        lastHandle = handle;
                    }
                    else
                    {
                        for (const auto &handle : pSource->GetHandles())
                        {
                            lastHandle = handle;
                            break;
                        }
                    }

                    if (!pSource->OnTrigger(lastHandle))
                    {
                        for (AU_ITERATE_N(z, i))
                        {
                            ResetLoopSourceFalseAlarm(loopSourceExs[z]);
                        }

                        bRet = false;
                        break;
                    }
                }

                pSource->OnFinishSleep();
            }
        }

        return bRet;
    }

    bool WaitMultipleAndObjects(const AuList<AuSPtr<ILoopSource>> &objects, bool bAlert, bool bBreakAPCs, bool bZeroTick, AuUInt64 qwTimeoutAbs, bool &bTooMany, bool &bTimeout)
    {
        bool bRet {};
        do
        {
            bRet = WaitMultipleAndObjects_(objects, bAlert, bBreakAPCs, bZeroTick, qwTimeoutAbs, bTooMany, bTimeout);
        }
        while (!bRet && !bTimeout && !bTooMany);
        return bRet;
    }
}