AuroraRPC/Source/AuRPCServerChannel.cpp

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

    File: AuRPCServerChannel.cpp
    Date: 2022-6-29
    Author: Reece
***/
#include <AuroraRuntime.hpp>
#include "AuRPC.hpp"
#include "AuRPCServerChannel.hpp"
#include "AuRPCRequest.hpp"
#include "AuRPCPipePacket.hpp"

AuRPCServerChannel::AuRPCServerChannel(AuSPtr<AuRPC> parent, AuSPtr<AuRPCServer> server) :
    parent(parent),
    pipe(this),
    server_(server)
{
    this->uConnectTime_ = AuTime::SteadyClockNS();
}

AuRPCServerChannel::~AuRPCServerChannel()
{
    this->RemoveFromParent();
}

AuSPtr<AuRPC> AuRPCServerChannel::ToContext()
{
    return this->parent;
}

void AuRPCServerChannel::SendResponse(AuSPtr<AuRPCResponse> response)
{
    if (response->message->flagWriteError)
    {
        this->FatalError();
        return;
    }

    AuRPCPipePacket packet;
    packet.serverResponse = response;
    this->pipe.SendPacket(packet);
}

AuString AuRPCServerChannel::ExportString()
{
    return this->pipe.pipe->ExportToString();
}

bool AuRPCServerChannel::OnConnect()
{
    RpcLogDebug("Server channel: on connect");
    return true;
}

void AuRPCServerChannel::OnDisconnect(bool error)
{
    RpcLogDebug("Server channel disconnected: {}", error);
    this->RemoveFromParent();
}

void AuRPCServerChannel::RemoveFromParent()
{
    if (auto pParent = this->server_)
    {
        AU_LOCK_GUARD(pParent->lock->AsWritable());

        if (auto pChannel = pParent->channel)
        {
            AuRemoveIf(pChannel->subchannels_,
                       [=](AuSPtr<AuRPCServerChannel> pChannel) -> bool
            {
                return pChannel.get() == this;
            });
        }
    }
}

bool AuRPCServerChannel::OnDataAvailable(AuByteBuffer& view)
{
    do
    {
        auto bytesAvailable = view.RemainingBytes();

        if (bytesAvailable < 4)
        {
            return true;
        }

        auto oldRead = view.readPtr;
        
        auto frameLength = view.Read<AuUInt32>();
        if (!frameLength)
        {
            FatalError();
            return false;
        }

        if (frameLength > bytesAvailable)
        {
            view.readPtr = oldRead;
            return true;
        }

        auto packetType = view.Read<AuUInt8>();

        if (packetType == kRequestConnect)
        {
            if (this->isTempChannel_)
            {
                this->SendToNewChannel();
            }
            else
            {
                this->SendConnectOK();
            }
        }
        else if (packetType == kRequestRPC)
        {
            auto request = AuMakeShared<AuRPCRequest>();
            if (!request)
            {
                SysPushErrorMem();
                view.readPtr = oldRead;
                return true;
            }

            request->serviceId = view.Read<AuUInt32>();
            request->methodId = view.Read<AuUInt32>();
            request->cookie = view.Read<AuUInt64>();

            auto oldLength = view.length;
            auto oldWriteHead = view.writePtr;
            view.length = (oldRead - view.base) + frameLength;
            view.writePtr = view.base + view.length;

            this->server_->Dispatch(this, request, &view);

            view.readPtr = oldRead + frameLength;
            view.writePtr = oldWriteHead;
            view.length = oldLength;
        }
        else if (packetType == kGeneralServerMessage)
        {
            auto oldLength = view.length;
            auto oldWriteHead = view.writePtr;
            view.length = (oldRead - view.base) + frameLength;
            view.writePtr = view.base + view.length;

            if (auto pCallbacks = this->server_->pCallbacks)
            {
                pCallbacks->OnMessage(this->SharedFromThis(),
                                      view);
            }

            view.readPtr = oldRead + frameLength;
            view.writePtr = oldWriteHead;
            view.length = oldLength;
        }

    }
    while (true);

    return true;
}

AuUInt64 AuRPCServerChannel::GetConnectTimeNS()
{
    return this->uConnectTime_;
}

void AuRPCServerChannel::SendMessage(const AuMemoryViewRead &view)
{
    auto pMessage = AuMakeSharedPanic<AuRPCResponseOwned>();
    pMessage->PrepareResponse(kGeneralClientMessage);
    pMessage->buffer->Write(view.ptr, view.length);
    pMessage->FinalizeWrite();
    this->SendResponse(pMessage);
}

void AuRPCServerChannel::SendConnectOK()
{
    RpcLogDebug("AuRPCServerChannel::SendConnectOK");

    auto res = AuMakeShared<AuRPCResponseOwned>();
    if (!res)
    {
        FatalError();
        return;
    }

    res->PrepareResponse(kResponseConnectOK);
    res->FinalizeWrite();

    this->SendResponse(res);
}

void AuRPCServerChannel::SendToNewChannel()
{
    RpcLogDebug("AuRPCServerChannel::SendToNewChannel");

    auto res = AuMakeShared<AuRPCResponseOwned>();
    if (!res)
    {
        FatalError();
        return;
    }

    res->PrepareResponse(kResponseMulticonnect);
    auto channel = this->server_->NewChannel(false);
    if (!channel)
    {
        this->FatalError();
        return;
    }

    if (!AuTryInsert(this->subchannels_, channel))
    {
        this->FatalError();
        return;
    }

    res->buffer->Write(channel->ExportString());

    res->FinalizeWrite();

    this->SendResponse(res);
}

void AuRPCServerChannel::FatalError()
{
    RpcLogDebug("AuRPCServerChannel::FatalError");
    this->pipe.Deinit();
}

bool AuRPCServerChannel::Init()
{
    return this->pipe.Init(this->parent->optPipeLength);
}