/*---------------------------------------------------------------------------*
  Project:  Horizon
  File:     rdt_SenderImpl.cpp

  Copyright (C)2009-2012 Nintendo Co., Ltd.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Rev: 46347 $
 *---------------------------------------------------------------------------*/

#include "stdafx.h"

#include "rdt_SenderImpl.h"

#include <nn/rdt/CTR/rdt_define.h>
#include <nn/rdt/CTR/rdt_Result.h>

#include "rdt_Stopwatch.h"

#include "Test.h"


namespace
{

}  // End of anonymous namespace


namespace nn { namespace rdt { namespace CTR {


// Base class for "state."
class SenderStateBase{
public:
    virtual ~SenderStateBase(void){}

    virtual void initialize(SenderImpl *pSender); // Called when this state begins
    virtual void finalize  (SenderImpl *pSender); // Called when this state ends
    void update    (SenderImpl *pSender);
    virtual void updatePrologue   (SenderImpl *pSender);
    virtual void updateCore       (SenderImpl *pSender);
    virtual void updateEpilogue   (SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const = 0;

protected:
    SenderStateBase(void){}
};


void SenderStateBase::initialize(SenderImpl *pSender)
{
    (void)pSender;
}


void SenderStateBase::finalize(SenderImpl *pSender)
{
    (void)pSender;
}


void SenderStateBase::updatePrologue(SenderImpl *pSender)
{
    (void)pSender;
}


void SenderStateBase::updateCore(SenderImpl *pSender)
{
    (void)pSender;
}


void SenderStateBase::updateEpilogue(SenderImpl *pSender)
{
    (void)pSender;
}


void SenderStateBase::update(SenderImpl *pSender)
{
    updatePrologue(pSender);
    updateCore(pSender);
    updateEpilogue(pSender);
}


class SenderStateOpenRequested : public SenderStateBase{
public:
    static SenderStateBase* getInstance(void);

    virtual void updateCore(SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const;

protected:
    SenderStateOpenRequested(void){}
};


class SenderStateOpening : public SenderStateBase{
public:
    static SenderStateBase* getInstance(void);

    virtual void updateCore(SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const;

protected:
    SenderStateOpening(void){}
};


class SenderStateOpened : public SenderStateBase{
public:
    static SenderStateBase* getInstance(void);

    virtual void updateCore(SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const;

protected:
    SenderStateOpened(void){}
};


class SenderStateCloseRequested : public SenderStateBase{
public:
    static SenderStateBase* getInstance(void);

    virtual void updateCore(SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const;

protected:
    SenderStateCloseRequested(void){}
};


class SenderStateClosing : public SenderStateBase{
public:
    static SenderStateBase* getInstance(void);

    virtual void updateCore(SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const;

protected:
    SenderStateClosing(void){}
};


class SenderStateClosed : public SenderStateBase{
public:
    static SenderStateBase* getInstance(void);

    virtual void initialize(SenderImpl *pSender);
    virtual void updateCore(SenderImpl *pSender);
    virtual enum SenderState getStatus(void) const;

protected:
    SenderStateClosed(void){}
};


// Below is the implementation of the State derived class.
SenderStateBase* SenderStateClosed::getInstance(void)
{
    static SenderStateClosed s_instance;
    return &s_instance;
}


enum SenderState SenderStateClosed::getStatus(void) const
{
    return SENDER_STATE_CLOSED;
}


void SenderStateClosed::initialize(SenderImpl *pSender)
{
    ASSERT(pSender!=NULL);

    pSender->clear();
}


void SenderStateClosed::updateCore(SenderImpl *pSender)
{
    ASSERT(pSender!=NULL);

    // Respond with RST to segments without RST that were received during CLOSED state
    Segment seg;
    if(pSender->pullSegment(&seg).IsSuccess() && !seg.IsRst())
    {
#if 0
        LOG("The Sender is in a CLOSED state, but because the segment was received, responds with RST. \n");
        LOG("The received segment contains \n.");
        seg.PrintDebugInfo();
        LOG("   \n");
        const u32 SEQ = 0;
        pSender->sendRstSegment(SEQ);
#else
        LOG("Sender is in CLOSED state, but received segment.  Ignored.\n");
#endif
    }
}


SenderStateBase* SenderStateOpenRequested::getInstance(void)
{
    static SenderStateOpenRequested s_instance;
    return &s_instance;
}


enum SenderState SenderStateOpenRequested::getStatus(void) const
{
    return SENDER_STATE_OPEN_REQUESTED;
}


void SenderStateOpenRequested::updateCore(SenderImpl *pSender)
{
    // Send connection request segment
    pSender->sendSynSegment();

    // Go to the next state.
    pSender->setNextState(SenderStateOpening::getInstance());
}


SenderStateBase* SenderStateOpening::getInstance(void)
{
    static SenderStateOpening s_instance;
    return &s_instance;
}


enum SenderState SenderStateOpening::getStatus(void) const
{
    return SENDER_STATE_OPENING;
}


void SenderStateOpening::updateCore(SenderImpl *pSender)
{
    ASSERT(pSender!=NULL);

    // Check content of the received segment.
    Segment seg;
    if(pSender->pullSegment(&seg).IsSuccess())
    {
        pSender->processReceivedSegment(seg);

        if(seg.IsRst())
        {
            // Check if the RST is for this SYN. If not, discard segment.
            if(seg.IsAck() && seg.GetAckNumber()==pSender->getInitialSequenceNumber()+1)
            {
                // Treat as though the SYN was refused. To CLOSED.
                LOG("SYN rejected.  CLOSED... ack of segment = %u\n", seg.GetAckNumber());
                pSender->setNextState(SenderStateClosed::getInstance());
                pSender->errorHandling(ResultResetReceived());
                return;
            }
            else
            {
                LOG("Ignored RST segment.\n");
            }
        }
        else if(seg.IsAck())
        {
            if(seg.GetAckNumber()==pSender->getInitialSequenceNumber()+1)
            {
                // Transition to next state because an ACK was received for the SYN.
                pSender->setNextState(SenderStateOpened::getInstance());
            }
            else
            {
                LOG("ack : %u\n", seg.GetAckNumber());
                LOG("una : %u\n", pSender->getUnacknowledgeNumber());
                LOG("nxt : %u\n", pSender->getNextSequenceNumber());
                LOG("It seems that it isn't ACK for SYN.  Ignored\n");
            }
        }
    }

    // Resend process.
    pSender->processResending();
}


SenderStateBase* SenderStateOpened::getInstance(void)
{
    static SenderStateOpened s_instance;
    return &s_instance;
}


enum SenderState SenderStateOpened::getStatus(void) const
{
    return SENDER_STATE_OPENED;
}


void SenderStateOpened::updateCore(SenderImpl *pSender)
{
    ASSERT(pSender!=NULL);

    // Check content of the received segment.
    Segment seg;
    if(pSender->pullSegment(&seg).IsSuccess())
    {
        pSender->processReceivedSegment(seg);

        if(seg.IsRst())
        {
            // Because it was RST, goes to CLOSED.
            pSender->setNextState(SenderStateClosed::getInstance());
            pSender->errorHandling(ResultResetReceived());
            return;
        }
    }

    bool bSent = false;  // Set to TRUE if the send process has been executed.

    // Resend process.
    bSent = pSender->processResending();

    // A chance for data transmission if the send process has not occurred even once.
    if(!bSent)
    {
        if(!pSender->isSendBufferEmpty())
        {
            pSender->sendData();
            bSent = true;
        }
    }
}


SenderStateBase* SenderStateCloseRequested::getInstance(void)
{
    static SenderStateCloseRequested s_instance;
    return &s_instance;
}


enum SenderState SenderStateCloseRequested::getStatus(void) const
{
    return SENDER_STATE_CLOSE_REQUESTED;
}


void SenderStateCloseRequested::updateCore(SenderImpl *pSender)
{
    ASSERT(pSender!=NULL);

    // Check content of the received segment. Around this is the same as the Opened state.
    Segment seg;
    if(pSender->pullSegment(&seg).IsSuccess())
    {
        pSender->processReceivedSegment(seg);

        if(seg.IsRst())
        {
            // Because it was RST, goes to CLOSED.
            pSender->setNextState(SenderStateClosed::getInstance());
            pSender->errorHandling(ResultResetReceived());
            return;
        }
    }

    bool bSent = false;  // Set to TRUE if the send process has been executed.

    // Resend process.
    bSent = pSender->processResending();

    if(pSender->isSendBufferEmpty())
    {
        // Send FIN segment
        if(!bSent)
        {
            pSender->sendFinSegment();
            bSent = true;

            // To CLOSING state.
            pSender->setNextState(SenderStateClosing::getInstance());
        }
    }
    else
    {
        // Releases the send buffer data
        if(!bSent)
        {
            pSender->sendData();
            bSent = true;
        }
    }

    // A chance for data transmission if the send process has not occurred even once.
    if(!bSent)
    {
        if(!pSender->isSendBufferEmpty())
        {
            pSender->sendData();
            bSent = true;
        }
    }
}


SenderStateBase* SenderStateClosing::getInstance(void)
{
    static SenderStateClosing s_instance;
    return &s_instance;
}


enum SenderState SenderStateClosing::getStatus(void) const
{
    return SENDER_STATE_CLOSING;
}


void SenderStateClosing::updateCore(SenderImpl *pSender)
{
    ASSERT(pSender!=NULL);

    // Resend process.
    pSender->processResending();

    // Check content of the received segment.
    Segment seg;
    if(pSender->pullSegment(&seg).IsSuccess())
    {
        pSender->processReceivedSegment(seg);

        if(seg.IsRst())
        {
            // Because it was RST, goes to CLOSED.
            pSender->setNextState(SenderStateClosed::getInstance());
            pSender->errorHandling(ResultResetReceived());
            return;
        }
        else if(seg.IsAck() && seg.GetAckNumber()==pSender->m_sendBuffer.GetCurrentSequenceNumber()+1)
        {
            // Check content of the received segment. (FIN check.)
            // Because an ACK was received for the FIN, goes to CLOSED.
            pSender->setNextState(SenderStateClosed::getInstance());
        }
        else
        {
            VERBOSE("Although a segment was received, it does not seem to be an ACK segment to FIN. Destroy. \n");
        }
    }
}



//
SenderImpl::SenderImpl(void) throw()
     :m_initialized(false)
{
}


//
SenderImpl::~SenderImpl(void)
{
    Finalize();
}


#ifdef _WIN32
nn::Result SenderImpl::Initialize(SOCKET sock, void *pSendBuf, u16 sendBufSize)
#else
nn::Result SenderImpl::Initialize(u16 nodeId, u8 port, void *pSendBuf, u16 sendBufSize)
#endif
{
    if(m_initialized)
    {
        return ResultAlreadyInitialized();
    }
    else
    {
        if(pSendBuf==NULL)
        {
            return ResultNullPointer();
        }

        if(sendBufSize==0)
        {
            return ResultInvalidSize();
        }

#ifdef _WIN32
        nn::Result result = HostBase::Initialize(sock);
#elif defined(NN_PLATFORM_CTR)
        nn::Result result = HostBase::Initialize(nodeId, port);
#endif
        if(result.IsFailure())
        {
            return result;
        }
        else
        {
            m_sendBuffer.Initialize(pSendBuf, sendBufSize);
            m_pState     = SenderStateClosed::getInstance();
            m_pNextState = NULL;

            clear();

            m_initialized = true;
            return ResultSuccess();
        }
    }
}


void SenderImpl::Finalize(void)
{
    if(m_initialized)
    {
        m_initialized = false;
        m_sendBuffer.Finalize();
        HostBase::Finalize();
    }
    else
    {
        // Do nothing.
    }
}


nn::Result SenderImpl::Process(void)
{
    ASSERT(m_initialized);

    // The update function according to the state
    if(m_pState)
    {
        m_pState->update(this);
    }

    // State Transitions
    changeState();

    // For debugging
    //    PrintDebugInfo();

    // Errors are returned here.
    // If returned, errors are reset.
    nn::Result ret = GetErrorCode();
    errorHandling(ResultSuccess());
    return ret;
}


nn::Result SenderImpl::Open(void)
{
    ASSERT(m_initialized);

    if(GetStatus()==SENDER_STATE_CLOSED)
    {
        setNextState(SenderStateOpenRequested::getInstance());
        changeState();
        return ResultSuccess();
    }
    else
    {
        return ResultUntimelyFunctionCall();
    }
}


nn::Result SenderImpl::Close(void)
{
    ASSERT(m_initialized);

    if(GetStatus()==SENDER_STATE_OPENED)
    {
        setNextState(SenderStateCloseRequested::getInstance());
        changeState();
        return ResultSuccess();
    }
    else
    {
        // Error if the Close function is called while in a CLOSED state.
        // This behavior follows the TCP RFC, and this behavior is also included here.
        return ResultUntimelyFunctionCall();
    }
}


nn::Result SenderImpl::Send(const void *pBuf, size_t bufSize)
{
    ASSERT(m_initialized);

    if(pBuf==NULL)
    {
        return ResultNullPointer();
    }

    if(bufSize==0)
    {
        return ResultDoNothing();
    }

    if(GetStatus()!=SENDER_STATE_OPENED)
    {
        return ResultUntimelyFunctionCall();
    }

    if(m_sendBuffer.Push(pBuf, bufSize))
    {
        return ResultSuccess();
    }
    else
    {
        return ResultSendBufferIsNotAvailable();
    }
}


void SenderImpl::Cancel(void)
{
    ASSERT(m_initialized);

    // Cancel processes execute immediately without waiting for the Process function.
    // This way of implementing error handling might be easier for the application to use.
    // 

    // RST transmission
    sendRstSegment(m_sendBuffer.GetCurrentSequenceNumber());

    // Immediately to Closed state.
    setNextState(SenderStateClosed::getInstance());
    changeState();
}


enum SenderState SenderImpl::GetStatus(void) const
{
    ASSERT(m_initialized);
    ASSERT(m_pState!=NULL);

    return m_pState->getStatus();
}


bool SenderImpl::processResending(void)
{
    Segment seg;
    // Either a segment that had met a timeout was found in the queue, or such a segment was found and is in a state to wait for the sending of the remaining segments to complete.
    // 
    // 
    if(m_resendQueue.IsResendMode())
    {
        bool ret = m_resendQueue.Front(&seg);
        ASSERT(ret);
        VERBOSE("Execute the new send or resend process. \n");
        VERBOSE("The send segment sequence number is: %d. \n", seg.GetSeqNumber());
        putSegment(seg);

        static detail::Stopwatch s_sp("ResendQueue::TryAgain()");
        s_sp.Start();
        m_resendQueue.TryAgain();  // Sends the first request in the queue to the end.
        s_sp.Stop();
        return true;
    }
    else
    {
        return false;
    }
}


void SenderImpl::sendData(void)
{
    if(m_sendBuffer.IsEmpty())
    {
        VERBOSE("The send buffer was empty, so the send process is not run. \n");
        return;
    }

    u32 unackDataSize = m_resendQueue.GetTotalDataSize();
    if(unackDataSize >= m_remoteWindowSize)
    {
        VERBOSE("The unconfirmed received data is larger than the receive window size, so the data send is skipped. \n");
        return;
    }

    if(m_resendQueue.IsFull())
    {
        VERBOSE("The resend queue is full, so the send process is not run. \n");
        return;
    }

    size_t vacant = m_remoteWindowSize - unackDataSize;
    size_t pullSize = min(Segment::PAYLOAD_SIZE, vacant);  // Amount taken from the send buffer.
    ASSERT(pullSize > 0);

    // The data send process.
    Segment seg;
    seg.ClearHeader();
    u32 seq = 0;

    // Runs the process to pack data in the segment.
    size_t sz = m_sendBuffer.Pull(seg.payload, &seq, pullSize);
    ASSERT(sz > 0);

    // To get to here, the send process must be guaranteed to have been run (that is, the resend queue must have space).
    // 
    seg.header.dataLength = sz;
    seg.SetSeqNumber(seq);
    putSegmentWithResend(seg);
}


void SenderImpl::sendSynSegment(void)
{
    Segment seg;
    seg.ClearHeader();
    seg.SetSeqNumber(getInitialSequenceNumber());
    seg.SetSyn();
    putSegmentWithResend(seg);
}


void SenderImpl::sendFinSegment(void)
{
    ASSERTMSG(m_sendBuffer.IsEmpty(), "You cannot request FIN if send buffer is not empty.");

    VERBOSE("sendFinSegment() called.\n");

    Segment seg;
    seg.ClearHeader();
    seg.SetFin();
    seg.SetSeqNumber(m_sendBuffer.GetCurrentSequenceNumber());
    putSegmentWithResend(seg);
}


void SenderImpl::clear(void)
{
    m_resendQueue.Clear();
    m_remoteWindowSize = 0;
#if 1
    m_iss = static_cast<u32>(0xffffffff & GetCurrentTimeAsMillisecond());
#else
    m_iss = 0xffffffff - 100;
#endif
    m_sendBuffer.Clear(m_iss);
    m_una = m_iss;
    m_nxt = m_iss;

    m_arrivals = 0;
}


bool SenderImpl::isValidAckNumber(u32 ack) const
{
    s32 s32_ack = static_cast<s32>(ack);
    s32 s32_una = static_cast<s32>(getUnacknowledgeNumber());
    s32 s32_nxt = static_cast<s32>(getNextSequenceNumber());

    // The permission ACK inequality expresses snd.una < seg.ack <= snd.nxt.
    if((0 <= s32_una - s32_ack) || (0 < s32_ack - s32_nxt))
    {
        return false;
    }
    else
    {
        return true;
    }
}



// State Transitions. Do nothing in particular if the next state is not set.
void SenderImpl::changeState(void)
{
    if(m_pNextState)
    {
        if(m_pState)
        {
            m_pState->finalize(this);
        }
        m_pState = m_pNextState;
        m_pNextState = NULL;
        m_pState->initialize(this);
    }
}


void SenderImpl::setNextState(SenderStateBase *p)
{
    ASSERT(p!=NULL);
    ASSERT(m_pNextState==NULL);

    m_pNextState = p;
}


void SenderImpl::putSegmentWithResend(const Segment &seg)
{
    // As long as the resend queue is full, reliable communication is not possible.
    ASSERT(!m_resendQueue.IsFull());

    putSegment(seg);

    // All segments depend on being resend targets.
    // If the SYN segment is removed from the resend target, it will not work.
    // 
    m_nxt = seg.GetLastSeqNumber() + 1;

    // Place a segment in the resend queue.
    // The sender must resend if an "arrival" cannot be confirmed.
    // The receiver does not track whether its response is received by the sender.
    // If the receiver's response is not received by the sender, the sender must resend.
    bool ret = m_resendQueue.Push(seg);
    if(!ret)
    {
        errorHandling(ResultResendQueueIsFull());
        PANIC("It seems that resend queue in RDT library is full.");
    }
}


void SenderImpl::processReceivedSegment(const Segment &seg)
{
    // The processes that must be run when a segment arrives are summarized here.
    // 

    ++m_arrivals;

    // ACK field check
    if(seg.IsAck())
    {
        const u32 ack = seg.GetAckNumber();
        if(isValidAckNumber(ack))
        {
            m_una = ack;

            // Packets for which distribution can be confirmed can be deleted from the resend queue.
            VERBOSE("ACK number %d was received. \n", ack);
            m_resendQueue.Remove(ack);

            // Update window size
            m_remoteWindowSize = seg.GetWindowSize();
        }
        else
        {
            VERBOSE("una : %d\n", getUnacknowledgeNumber());
            VERBOSE("nxt : %d\n", getNextSequenceNumber());
            VERBOSE("ACK number is not valid or has already been received. (%u)\n", ack);
        }
    }
}


void SenderImpl::PrintDebugInfo(void) const
{
    ASSERT(m_initialized);

    m_resendQueue.PrintDebugInfo();
    m_sendBuffer.PrintDebugInfo();
    LOG("m_remoteWindowSize: %d\n", m_remoteWindowSize);
    LOG("m_arrivals: %u\n", m_arrivals);
}


void SenderImpl::PrintProperty(void)
{
    LOG("m_sendBuffer: %d (%d)\n",       offsetof(SenderImpl, m_sendBuffer), sizeof(SendBuffer));
    LOG("m_remoteWindowSize: %d (%d)\n", offsetof(SenderImpl, m_remoteWindowSize), sizeof(u16));
    LOG("m_resendQueue: %d (%d)\n",      offsetof(SenderImpl, m_resendQueue), sizeof(ResendQueue));
    LOG("m_pState: %d (%d)\n",           offsetof(SenderImpl, m_pState), sizeof(SenderStateBase*));
    LOG("m_pNextState: %d (%d)\n",       offsetof(SenderImpl, m_pNextState), sizeof(SenderStateBase*));
    LOG("m_arrivals: %d (%d)\n",         offsetof(SenderImpl, m_arrivals), sizeof(u32));

    LOG("sizeof(SenderImpl)=%ld\n", (long) sizeof(SenderImpl));
}


// This stand-alone test aims to be a test that can be run without a Receiver, but it is pending.
// 
void SenderImpl::Test(void)
{
    /*
    const int BUFSIZE = 1024;
    char buf[BUFSIZE];
    SenderImpl s;
    const int SUCCESS = 0;
    CU_ASSERT(s.GetStatus()==SENDER_STATE_CLOSED);
    CU_ASSERT(s.Open()==SUCCESS);
    for(int i=0; i10; ++i)
    {
        CU_ASSERT(s.Process()==SUCCESS);
        CU_ASSERT(s.GetStatus()==SENDER_STATE_OPENING);
        SleepCurrentThread(50);
    }
    CU_ASSERT(s.Cancel()==SUCCESS);
    while(1)
    {
        CU_ASSERT(s.Process()==SUCCESS);
        CU_ASSERT(s.GetStatus()==SENDER_STATE_CLOSED);
        SleepCurrentThread(50);
    }
     



*/
}


}}} // namespace nn::rdt::CTR