/*
* Copyright (c) 2013-2021, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#include <string.h>
#include "I2PEndian.h"
#include "Log.h"
#include "RouterContext.h"
#include "I2NPProtocol.h"
#include "Tunnel.h"
#include "Transports.h"
#include "TransitTunnel.h"

namespace i2p {
    namespace tunnel {
        TransitTunnel::TransitTunnel(uint32_t receiveTunnelID,
                                     const uint8_t *nextIdent, uint32_t nextTunnelID,
                                     const uint8_t *layerKey, const uint8_t *ivKey) :
                TunnelBase(receiveTunnelID, nextTunnelID, nextIdent) {
            m_Encryption.SetKeys(layerKey, ivKey);
        }

        void TransitTunnel::EncryptTunnelMsg(std::shared_ptr<const I2NPMessage> in, std::shared_ptr<I2NPMessage> out) {
            m_Encryption.Encrypt(in->GetPayload() + 4, out->GetPayload() + 4);
            i2p::transport::transports.UpdateTotalTransitTransmittedBytes(TUNNEL_DATA_MSG_SIZE);
        }

        TransitTunnelParticipant::~TransitTunnelParticipant() {
        }

        void TransitTunnelParticipant::HandleTunnelDataMsg(std::shared_ptr<i2p::I2NPMessage> &&tunnelMsg) {
            EncryptTunnelMsg(tunnelMsg, tunnelMsg);

            m_NumTransmittedBytes += tunnelMsg->GetLength();
            htobe32buf(tunnelMsg->GetPayload(), GetNextTunnelID());
            tunnelMsg->FillI2NPMessageHeader(eI2NPTunnelData);
            m_TunnelDataMsgs.push_back(tunnelMsg);
        }

        void TransitTunnelParticipant::FlushTunnelDataMsgs() {
            if (!m_TunnelDataMsgs.empty()) {
                auto num = m_TunnelDataMsgs.size();
                if (num > 1)
                    LogPrint(eLogDebug, "TransitTunnel: ", GetTunnelID(), "->", GetNextTunnelID(), " ", num);
                i2p::transport::transports.SendMessages(GetNextIdentHash(), m_TunnelDataMsgs);
                m_TunnelDataMsgs.clear();
            }
        }

        void TransitTunnel::SendTunnelDataMsg(std::shared_ptr<i2p::I2NPMessage> msg) {
            LogPrint(eLogError, "TransitTunnel: We are not a gateway for ", GetTunnelID());
        }

        void TransitTunnel::HandleTunnelDataMsg(std::shared_ptr<i2p::I2NPMessage> &&tunnelMsg) {
            LogPrint(eLogError, "TransitTunnel: Incoming tunnel message is not supported ", GetTunnelID());
        }

        void TransitTunnelGateway::SendTunnelDataMsg(std::shared_ptr<i2p::I2NPMessage> msg) {
            TunnelMessageBlock block;
            block.deliveryType = eDeliveryTypeLocal;
            block.data = msg;
            std::unique_lock<std::mutex> l(m_SendMutex);
            m_Gateway.PutTunnelDataMsg(block);
        }

        void TransitTunnelGateway::FlushTunnelDataMsgs() {
            std::unique_lock<std::mutex> l(m_SendMutex);
            m_Gateway.SendBuffer();
        }

        void TransitTunnelEndpoint::HandleTunnelDataMsg(std::shared_ptr<i2p::I2NPMessage> &&tunnelMsg) {
            auto newMsg = CreateEmptyTunnelDataMsg(true);
            EncryptTunnelMsg(tunnelMsg, newMsg);

            LogPrint(eLogDebug, "TransitTunnel: handle msg for endpoint ", GetTunnelID());
            m_Endpoint.HandleDecryptedTunnelDataMsg(newMsg);
        }

        std::shared_ptr<TransitTunnel> CreateTransitTunnel(uint32_t receiveTunnelID,
                                                           const uint8_t *nextIdent, uint32_t nextTunnelID,
                                                           const uint8_t *layerKey, const uint8_t *ivKey,
                                                           bool isGateway, bool isEndpoint) {
            if (isEndpoint) {
                LogPrint(eLogDebug, "TransitTunnel: endpoint ", receiveTunnelID, " created");
                return std::make_shared<TransitTunnelEndpoint>(receiveTunnelID, nextIdent, nextTunnelID, layerKey,
                                                               ivKey);
            } else if (isGateway) {
                LogPrint(eLogInfo, "TransitTunnel: gateway ", receiveTunnelID, " created");
                return std::make_shared<TransitTunnelGateway>(receiveTunnelID, nextIdent, nextTunnelID, layerKey,
                                                              ivKey);
            } else {
                LogPrint(eLogDebug, "TransitTunnel: ", receiveTunnelID, "->", nextTunnelID, " created");
                return std::make_shared<TransitTunnelParticipant>(receiveTunnelID, nextIdent, nextTunnelID, layerKey,
                                                                  ivKey);
            }
        }
    }
}