/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuNetStream.NT.cpp
    Date: 2022-8-17
    Author: Reece
***/
#include "Networking.hpp"
#include "AuNetStream.NT.hpp"
#include "AuNetSocket.hpp"
#include "AuNetWorker.hpp"
#include "AuNetEndpoint.hpp"
#include <Source/IO/Loop/LSEvent.hpp>

namespace Aurora::IO::Net
{
    NtAsyncNetworkTransaction::NtAsyncNetworkTransaction(SocketBase *pSocket) :
        pSocket(pSocket)
    {
        if (this->pSocket->GetRemoteEndpoint().transportProtocol == ETransportProtocol::eProtocolTCP)
        {
            this->dwRecvFlags = MSG_PARTIAL;
        }
    }

    NtAsyncNetworkTransaction::~NtAsyncNetworkTransaction()
    {
        Reset();
    }

    static void __stdcall WsaOverlappedCompletionRoutine(DWORD dwErrorCode,
                                                         DWORD cbTransferred,
                                                         LPWSAOVERLAPPED lpOverlapped,
                                                         DWORD dwFlags
    )
    {
        auto transaction = reinterpret_cast<NtAsyncNetworkTransaction *>(reinterpret_cast<AuUInt8 *>(lpOverlapped) - offsetof(NtAsyncNetworkTransaction, overlap));
        auto hold = AuExchange(transaction->pPin, {});

        if (dwErrorCode)
        {
            hold->bHasFailed = true;
            hold->dwOsErrorCode = dwErrorCode;
        }
        else if (!hold->dwLastAbstractStat)
        {
            return;
        }

        SetEvent(lpOverlapped->hEvent);
        auto pHold1 = AuExchange(hold->readView, {});
        auto pHold2 = AuExchange(hold->writeView, {});
        hold->CompleteEx(cbTransferred, true);
    }

    bool     NtAsyncNetworkTransaction::StartRead(AuUInt64 offset, const AuMemoryViewWrite &memoryView)
    {
        if (this->bDisallowRecv)
        {
            SysPushErrorIO("Recv isn't allowed");
            return false;
        }

        if (!this->pSocket)
        {
            return false;
        }

        if (this->pSocket->bHasEnded)
        {
            return false;
        }

        if (this->bIsIrredeemable)
        {
            SysPushErrorIO("Transaction was signaled to be destroyed to reset mid synchronizable operation. You can no longer use this stream object");
            return false;
        }

        if (!IDontWannaUsePorts())
        {
            return false;
        }

        if (!memoryView)
        {
            SysPushErrorArg();
            return {};
        }

        if (this->readView ||
            this->writeView)
        {
            SysPushErrorIO("IO Operation in progress");
            return {};
        }

        this->bLatch = false;

        this->writeView = memoryView;
        this->bHasFailed = false;

        this->dwLastAbstractStat = memoryView.length;
        this->dwLastAbstractOffset = offset;
        this->dwLastBytes = 0;

        this->overlap.Offset     = AuBitsToLower<AuUInt64>(offset);
        this->overlap.OffsetHigh = AuBitsToHigher<AuUInt64>(offset);

        this->bIsWriting = false;

        WSABUF bufferArray[] {
            {
                (ULONG)writeView.length,
                writeView.Begin<CHAR>()
            }
        };

        this->overlap.hEvent = this->GetAlertable();
        
        DWORD todo { this->dwRecvFlags };
        int ret;

        if (!this->bDatagramMode)
        {
            if (!pWSARecv)
            {
                return this->TranslateLastError(false, true);
            }

            ret = pWSARecv(this->GetSocket(),
                           bufferArray,
                           1,
                           NULL,
                           &todo,
                           &this->overlap,
                           WsaOverlappedCompletionRoutine);
        }
        else
        {
            if (!pWSARecvFrom)
            {
                return this->TranslateLastError(false, true);
            }

            this->iSocketLength = this->pSocket->endpointSize_;
            ret = pWSARecvFrom(this->GetSocket(),
                               bufferArray,
                               1,
                               NULL,
                               &todo,
                               (sockaddr *)netEndpoint.hint,
                               &this->iSocketLength,
                               &this->overlap,
                               WsaOverlappedCompletionRoutine);
        }

        return this->TranslateLastError(ret != -1);
    }

    bool     NtAsyncNetworkTransaction::StartWrite(AuUInt64 offset, const AuMemoryViewRead &memoryView)
    {
        if (this->bDisallowSend)
        {
            SysPushErrorIO("Send isn't allowed");
            return false;
        }

        if (this->bIsIrredeemable)
        {
            SysPushErrorIO("Transaction was signaled to be destroyed to reset mid synchronizable operation. You can no longer use this stream object");
            return false;
        }

        if (!IDontWannaUsePorts())
        {
            return false;
        }

        if (!this->pSocket)
        {
            return false;
        }

        if (this->pSocket->bHasEnded)
        {
            return false;
        }

        if (!memoryView)
        {
            SysPushErrorArg();
            return {};
        }

        if (this->readView ||
            this->writeView)
        {
            SysPushErrorIO("IO Operation in progress");
            return {};
        }

        this->bLatch = false;

        this->readView = memoryView;
        this->bHasFailed = false;

        this->dwLastAbstractStat = memoryView.length;
        this->dwLastAbstractOffset = offset;
        this->dwLastBytes = 0;

        this->bIsWriting = true;

        this->overlap.Offset     = AuBitsToLower<AuUInt64>(offset);
        this->overlap.OffsetHigh = AuBitsToHigher<AuUInt64>(offset);

        WSABUF bufferArray[] {
            {
                (ULONG)memoryView.length,
                (CHAR *)memoryView.Begin<CHAR>()
            }
        };

        this->overlap.hEvent = this->GetAlertable();
        
        int ret;
        if (!this->bDatagramMode)
        {
            if (!pWSASend)
            {
                return this->TranslateLastError(false, true);
            }

            ret = pWSASend(this->GetSocket(),
                          bufferArray,
                          1,
                          NULL,
                          this->dwRecvFlags,
                          &this->overlap,
                          WsaOverlappedCompletionRoutine);
        }
        else
        {
            if (!pWSASendTo)
            {
                return this->TranslateLastError(false, true);
            }

            this->iSocketLength = this->pSocket->endpointSize_;
            ret = pWSASendTo(this->GetSocket(),
                             bufferArray,
                             1,
                             NULL,
                             this->dwRecvFlags,
                             (sockaddr *)netEndpoint.hint,
                             EndpointToLength(netEndpoint),
                             &this->overlap,
                             WsaOverlappedCompletionRoutine);
        }

        return this->TranslateLastError(ret != -1);
    }

    bool     NtAsyncNetworkTransaction::TranslateLastError(bool bReturnValue, bool bForceFail)
    {
        auto er = bForceFail ?
            ERROR_IO_PREEMPTED :
            pWSAGetLastError();
        if (bReturnValue)
        {
            return true;
        }
        else if (er == ERROR_IO_PENDING)
        {
            if (AuExchange(this->bForceNextWait, false))
            {
                SysAssertDbg(this->pWaitable, "missing waitable for wait next");
                this->pWaitable->WaitOn(0);
            }
            return true;
        }
        else if ((er == ERROR_HANDLE_EOF) ||
                 (er == WSAECONNABORTED) ||
                 (er == WSAECONNRESET) ||
                 (er == WSAEDISCON))
        {
            this->dwLastAbstractStat = 0;
            this->bHasFailed = true; // to pass completion
            this->dwOsErrorCode = er;// to suppress actual error condition

            if (!AuExchange(this->bSendEOSOnce, true))
            {
                DispatchCb(0);
            }

            if (this->pSocket)
            {
                this->pSocket->SendEnd();
            }

            AuResetMember(this->readView);
            AuResetMember(this->writeView);

            this->pPin.reset();
            return true;
        }
        else
        {
            this->pPin.reset();
            this->Reset();
            this->dwOsErrorCode = er;
            this->bHasFailed = true;
            SysPushErrorNet("QoA async FIO error: {} on {}", this->dwOsErrorCode, (int)this->GetSocket());
            return false;
        }
    }

    bool NtAsyncNetworkTransaction::HasCompletedForGCWI()
    {
        return this->HasCompleted();
    }

    void NtAsyncNetworkTransaction::CleanupForGCWI()
    {
        this->overlap.hEvent = INVALID_HANDLE_VALUE;
        AuResetMember(this->pCompletionGroup_);
    }

    bool NtAsyncNetworkTransaction::TryAttachToCompletionGroup(const AuSPtr<CompletionGroup::ICompletionGroup> &pCompletionGroup)
    {
        if (bool(this->pCompletionGroup_) ||
            !pCompletionGroup)
        {
            return false;
        }

        auto pLoopSource = pCompletionGroup->GetTriggerLoopSource();
        if (!pLoopSource)
        {
            return false;
        }

        this->overlap.hEvent = (HANDLE)AuStaticCast<Loop::LSEvent>(pLoopSource)->GetHandle();
        pCompletionGroup->AddWorkItem(this->SharedFromThis());
        this->pCompletionGroup_ = pCompletionGroup;
        return true;
    }

    CompletionGroup::ICompletionGroupWorkHandle *NtAsyncNetworkTransaction::ToCompletionGroupHandle()
    {
        return this;
    }

    AuSPtr<CompletionGroup::ICompletionGroup> NtAsyncNetworkTransaction::GetCompletionGroup()
    {
        return this->pCompletionGroup_;
    }

    bool     NtAsyncNetworkTransaction::Complete()
    {
        return CompleteEx(0);
    }

    bool     NtAsyncNetworkTransaction::CompleteEx(AuUInt completeRoutine, bool bForce)
    {
        DWORD read {};

        if (!completeRoutine)
        {
            if (this->dwLastBytes || this->bHasFailed)
            {
                return true;
            }

            if (!this->readView &&
                !this->writeView)
            {
                if (bForce)
                {
                    if (!AuExchange(this->bSendEOSOnce, true))
                    {
                        DispatchCb(0);
                        return true;
                    }
                }

                return false;
            }

            if (::GetOverlappedResult((HANDLE)this->GetSocket(), &this->overlap, &read, false) && (read || bForce))
            {
                DispatchCb(read);
                return true;
            }
        }
        else
        {
            if ((this->dwOsErrorCode == ERROR_HANDLE_EOF) ||
                (this->dwOsErrorCode == WSAECONNABORTED) ||
                (this->dwOsErrorCode == WSAECONNRESET) ||
                (this->dwOsErrorCode == WSAEDISCON))
            {
                if (!AuExchange(this->bSendEOSOnce, true))
                {
                    DispatchCb(0);
                }
            }
            else
            {
                DispatchCb(completeRoutine);
            }

            return true;
        }

        return false;
    }

    bool     NtAsyncNetworkTransaction::HasFailed()
    {
        return this->bHasFailed &&
               this->dwOsErrorCode != ERROR_HANDLE_EOF &&
               this->dwOsErrorCode != WSAECONNABORTED &&
               this->dwOsErrorCode != WSAECONNRESET &&
               this->dwOsErrorCode != WSAEDISCON;
    }
    
    bool NtAsyncNetworkTransaction::HasErrorCode()
    {
        return this->bHasFailed &&
            this->dwOsErrorCode != ERROR_HANDLE_EOF;
    }

    bool NtAsyncNetworkTransaction::HasCompleted()
    {
        return this->bHasFailed ||
            this->dwLastBytes;
    }

    AuUInt   NtAsyncNetworkTransaction::GetOSErrorCode()
    {
        return this->dwOsErrorCode;
    }

    AuUInt32 NtAsyncNetworkTransaction::GetLastPacketLength()
    {
        return this->dwLastBytes;
    }

    void     NtAsyncNetworkTransaction::SetCallback(const AuSPtr<IAsyncFinishedSubscriber> &sub)
    {
        this->pSub = sub;
    }

    bool NtAsyncNetworkTransaction::Wait(AuUInt32 timeout)
    {
        return this->bLatch;
    }

    AuSPtr<AuLoop::ILoopSource> NtAsyncNetworkTransaction::NewLoopSource()
    {
        AuLoop::ILSEvent *optEvent {};

        if (auto pLoopSource = this->pCompletionGroup_->GetTriggerLoopSource())
        {
            return pLoopSource;
        }
        else
        {
            if (auto pWaitable = this->pWaitable)
            {
                return pWaitable;
            }
        }

        return {};
    }

    void NtAsyncNetworkTransaction::SetBaseOffset(AuUInt64 uBaseOffset)
    {

    }

    void NtAsyncNetworkTransaction::Reset()
    {
        if (this->dwLastAbstractStat)
        {
            this->bIsIrredeemable = true;
            this->bHasFailed = true;
            if (pCancelIoEx)
            {
                pCancelIoEx((HANDLE)this->GetSocket(), &this->overlap);
            }
            else
            {
                ::CancelIo((HANDLE)this->GetSocket());
            }
            this->dwOsErrorCode = ERROR_ABANDONED_WAIT_0;
        }
        else
        {
            this->bHasFailed = false;
        }

        this->dwLastBytes = 0;
        this->dwLastAbstractStat = 0;
    }

    void NtAsyncNetworkTransaction::MakeSyncable()
    {
        this->pWaitable = AuLoop::NewLSEventSlow(false, true);
        SysAssert(this->pWaitable);
        this->overlap.hEvent = (HANDLE)AuStaticCast<Loop::LSEvent>(this->pWaitable)->GetHandle();
    }

    void NtAsyncNetworkTransaction::ForceNextWriteWait()
    {
        this->bForceNextWait = true;
    }

    bool NtAsyncNetworkTransaction::IDontWannaUsePorts()
    {
        if (AuExchange(this->pPin, AuSharedFromThis()))
        {
            while (SleepEx(0, true) == WAIT_IO_COMPLETION)
            {

            }

            if (AuExchange(this->pPin, AuSharedFromThis()))
            {
                SysPushErrorUnavailableError();
                return {};
            }
        }

        return true;
    }

    void NtAsyncNetworkTransaction::DispatchCb(AuUInt32 read)
    {
        if (this->bIsWriting)
        {
            if (read != this->dwLastAbstractStat)
            {
                this->dwOsErrorCode = WSAEMSGSIZE;
                this->bHasFailed = true;
            }
        }

        this->dwLastAbstractStat = 0;
        this->dwLastBytes = read;
        if (AuExchange(this->bLatch, true))
        {
            return;
        }

        if (this->pSub)
        {
            this->RoutineCallCB(read);
        }
    }

#if defined(__AUHAS_COROUTINES_CO_AWAIT) && defined(AU_LANG_CPP_20_)
    AuVoidTask NtAsyncNetworkTransaction::RoutineCallCB_(AuUInt32 len)
    {
        if (this->pSub)
        {
            try
            {
                this->pSub->OnAsyncFileOpFinished(this->dwLastAbstractOffset, len);
            }
            catch (...)
            {
                SysPushErrorCatch();
            }
        }

        co_return;
    }
#endif

    void NtAsyncNetworkTransaction::RoutineCallCB(AuUInt32 len)
    {
    #if defined(__AUHAS_COROUTINES_CO_AWAIT) && defined(AU_LANG_CPP_20_)
        if (gRuntimeConfig.ioConfig.bAPCUseCoroutineStack)
        {
            this->RoutineCallCB_(len);
            return;
        }
    #endif

        if (this->pSub)
        {
            this->pSub->OnAsyncFileOpFinished(this->dwLastAbstractOffset, len);
        }
    }

    SOCKET NtAsyncNetworkTransaction::GetSocket()
    {
        return this->pSocket ? this->pSocket->ToPlatformHandle() : SOCKET {};
    }

    HANDLE NtAsyncNetworkTransaction::GetAlertable()
    {
        if (this->pCompletionGroup_)
        {
            auto pLoopSource = this->pCompletionGroup_->GetTriggerLoopSource();
            if (!pLoopSource)
            {
                return INVALID_HANDLE_VALUE;
            }

            return (HANDLE)AuStaticCast<Loop::LSEvent>(pLoopSource)->GetHandle();
        }
        else
        {
            if (auto pSocket = this->pSocket)
            {
                return (HANDLE)AuStaticCast<AuLoop::LSEvent>(pSocket->ToWorkerEx()->ToEvent())->GetHandle();
            }
            else
            {
                return INVALID_HANDLE_VALUE;
            }
        }
    }
}