// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2012 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_NET_H
#define BITCOIN_NET_H

#include "mruset.h"
#include "netbase.h"
#include "addrman.h"
#include "hash.h"
#include "streams.h"

#ifndef WIN32
#include <arpa/inet.h>
#endif

#include <limits>
#include <deque>


class CNode;
class CBlockIndex;
extern int nBestHeight;

const uint16_t nSocksDefault = 9050;
const uint16_t nPortZero = 0;


inline uint64_t ReceiveBufferSize() { return 1000*GetArg("-maxreceivebuffer", 5*1000); }
inline uint64_t SendBufferSize() { return 1000*GetArg("-maxsendbuffer", 1*1000); }

void AddOneShot(std::string strDest);
bool RecvLine(SOCKET hSocket, std::string& strLine);
bool GetMyExternalIP(CNetAddr& ipRet);
void AddressCurrentlyConnected(const CService& addr);
CNode* FindNode(const CNetAddr& ip);
CNode* FindNode(const CService& ip);
CNode* ConnectNode(CAddress addrConnect, const char *strDest = NULL, int64_t nTimeout=0);
bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false);
void MapPort();
unsigned short GetListenPort();
bool BindListenPort(const CService &bindAddr, std::string& strError=REF(std::string()));
void StartNode(void* parg);
bool StopNode();

enum
{
    LOCAL_NONE,   // unknown
    LOCAL_IF,     // address a local interface listens on
    LOCAL_BIND,   // address explicit bound to
    LOCAL_IRC,    // address reported by IRC (deprecated)
    LOCAL_HTTP,   // address reported by whatismyip.com and similar
    LOCAL_MANUAL, // address explicitly specified (-externalip=)

    LOCAL_MAX
};


bool IsPeerAddrLocalGood(CNode *pnode);
void AdvertiseLocal(CNode *pnode);
void SetLimited(enum Network net, bool fLimited = true);
bool IsLimited(enum Network net);
bool IsLimited(const CNetAddr& addr);
bool AddLocal(const CService& addr, int nScore = LOCAL_NONE);
bool AddLocal(const CNetAddr& addr, int nScore = LOCAL_NONE);
bool SeenLocal(const CService& addr);
bool IsLocal(const CService& addr);
bool GetLocal(CService &addr, const CNetAddr *paddrPeer = NULL);
bool IsReachable(const CNetAddr &addr);
void SetReachable(enum Network net, bool fFlag = true);
CAddress GetLocalAddress(const CNetAddr *paddrPeer = NULL);


enum
{
    MSG_TX = 1,
    MSG_BLOCK
};


/** Thread types */
enum threadId
{
    THREAD_SOCKETHANDLER,
    THREAD_OPENCONNECTIONS,
    THREAD_MESSAGEHANDLER,
    THREAD_RPCLISTENER,
    THREAD_DNSSEED,
    THREAD_ADDEDCONNECTIONS,
    THREAD_DUMPADDRESS,
    THREAD_RPCHANDLER,
    THREAD_MINTER,
    THREAD_SCRIPTCHECK,
    THREAD_NTP,
    THREAD_IPCOLLECTOR,

    THREAD_MAX
};

extern bool fClient;
extern bool fDiscover;
extern bool fNoListen;

extern bool fDiscover;
extern uint64_t nLocalServices;
extern uint64_t nLocalHostNonce;
extern CAddress addrSeenByPeer;
extern std::array<int, THREAD_MAX> vnThreadsRunning;
extern CAddrMan addrman;

extern std::vector<CNode*> vNodes;
extern CCriticalSection cs_vNodes;
extern std::vector<std::string> vAddedNodes;
extern CCriticalSection cs_vAddedNodes;
extern std::map<CInv, CDataStream> mapRelay;
extern std::deque<std::pair<int64_t, CInv> > vRelayExpiration;
extern CCriticalSection cs_mapRelay;
extern std::map<CInv, int64_t> mapAlreadyAskedFor;




class CNodeStats
{
public:
    uint64_t nServices;
    int64_t nLastSend;
    int64_t nLastRecv;
    int64_t nTimeConnected;
    std::string addrName;
    int32_t nVersion;
    std::string strSubVer;
    bool fInbound;
    int64_t nReleaseTime;
    int32_t nStartingHeight;
    int32_t nMisbehavior;
    uint64_t nSendBytes;
    uint64_t nRecvBytes;
    bool fSyncNode;
};





/** Information about a peer */
class CNode
{
public:
    // socket
    uint64_t nServices;
    SOCKET hSocket;
    CDataStream vSend;
    CDataStream vRecv;
    uint64_t nSendBytes;
    uint64_t nRecvBytes;
    CCriticalSection cs_vSend;
    CCriticalSection cs_vRecv;
    int64_t nLastSend;
    int64_t nLastRecv;
    int64_t nLastSendEmpty;
    int64_t nTimeConnected;
    int32_t nHeaderStart;
    uint32_t nMessageStart;
    CAddress addr;
    std::string addrName;
    CService addrLocal;
    int32_t nVersion;
    std::string strSubVer;
    bool fOneShot;
    bool fClient;
    bool fInbound;
    bool fNetworkNode;
    bool fSuccessfullyConnected;
    bool fDisconnect;
    CSemaphoreGrant grantOutbound;
protected:
    int nRefCount;

    // Denial-of-service detection/prevention
    // Key is IP address, value is banned-until-time
    static std::map<CNetAddr, int64_t> setBanned;
    static CCriticalSection cs_setBanned;
    int nMisbehavior;

public:
    int64_t nReleaseTime;
    uint256 hashContinue;
    CBlockIndex* pindexLastGetBlocksBegin;
    uint256 hashLastGetBlocksEnd;
    int32_t nStartingHeight;
    bool fStartSync;

    // flood relay
    std::vector<CAddress> vAddrToSend;
    std::set<CAddress> setAddrKnown;
    bool fGetAddr;
    std::set<uint256> setKnown;
    uint256 hashCheckpointKnown; // ppcoin: known sent sync-checkpoint
    int64_t nNextAddrSend;
    int64_t nNextLocalAddrSend;
    int64_t nNextInvSend;

    // inventory based relay
    mruset<CInv> setInventoryKnown;
    std::vector<CInv> vInventoryToSend;
    CCriticalSection cs_inventory;
    std::multimap<int64_t, CInv> mapAskFor;

    CNode(SOCKET hSocketIn, CAddress addrIn, std::string addrNameIn = "", bool fInboundIn=false) : vSend(SER_NETWORK, MIN_PROTO_VERSION), vRecv(SER_NETWORK, MIN_PROTO_VERSION)
    {
        nServices = 0;
        hSocket = hSocketIn;
        nLastSend = 0;
        nLastRecv = 0;
        nSendBytes = 0;
        nRecvBytes = 0;
        nLastSendEmpty = GetTime();
        nTimeConnected = GetTime();
        nHeaderStart = -1;
        nMessageStart = std::numeric_limits<uint32_t>::max();
        addr = addrIn;
        addrName = addrNameIn.empty() ? addr.ToStringIPPort() : addrNameIn;
        nVersion = 0;
        strSubVer.clear();
        fOneShot = false;
        fClient = false; // set by version message
        fInbound = fInboundIn;
        fNetworkNode = false;
        fSuccessfullyConnected = false;
        fDisconnect = false;
        nRefCount = 0;
        nReleaseTime = 0;
        hashContinue = 0;
        pindexLastGetBlocksBegin = 0;
        hashLastGetBlocksEnd = 0;
        nStartingHeight = -1;
        nNextLocalAddrSend = 0;
        nNextAddrSend = 0;
        nNextInvSend = 0;
        fStartSync = false;
        fGetAddr = false;
        nMisbehavior = 0;
        hashCheckpointKnown = 0;
        setInventoryKnown.max_size((size_t)SendBufferSize() / 1000);

        // Be shy and don't send version until we hear
        if (hSocket != INVALID_SOCKET && !fInbound)
            PushVersion();
    }

    ~CNode()
    {
        if (hSocket != INVALID_SOCKET)
        {
            CloseSocket(hSocket);
        }
    }


private:
    // Network usage totals
    static CCriticalSection cs_totalBytesRecv;
    static CCriticalSection cs_totalBytesSent;
    static uint64_t nTotalBytesRecv;
    static uint64_t nTotalBytesSent;
    CNode(const CNode&);
    void operator=(const CNode&);
public:


    int GetRefCount()
    {
        return std::max(nRefCount, 0) + (GetTime() < nReleaseTime ? 1 : 0);
    }

    CNode* AddRef(int64_t nTimeout=0)
    {
        if (nTimeout != 0)
            nReleaseTime = std::max(nReleaseTime, GetTime() + nTimeout);
        else
            nRefCount++;
        return this;
    }

    void Release()
    {
        nRefCount--;
    }



    void AddAddressKnown(const CAddress& addr)
    {
        setAddrKnown.insert(addr);
    }

    void PushAddress(const CAddress& addr)
    {
        // Known checking here is only to save space from duplicates.
        // SendMessages will filter it again for knowns that were added
        // after addresses were pushed.
        if (addr.IsValid() && !setAddrKnown.count(addr))
            vAddrToSend.push_back(addr);
    }


    void AddInventoryKnown(const CInv& inv)
    {
        {
            LOCK(cs_inventory);
            setInventoryKnown.insert(inv);
        }
    }

    void PushInventory(const CInv& inv)
    {
        {
            LOCK(cs_inventory);
            if (!setInventoryKnown.count(inv))
                vInventoryToSend.push_back(inv);
        }
    }

    void AskFor(const CInv& inv)
    {
        // We're using mapAskFor as a priority queue,
        // the key is the earliest time the request can be sent
        int64_t& nRequestTime = mapAlreadyAskedFor[inv];
        if (fDebugNet)
            printf("askfor %s   %" PRId64 " (%s)\n", inv.ToString().c_str(), nRequestTime, DateTimeStrFormat("%H:%M:%S", nRequestTime/1000000).c_str());

        // Make sure not to reuse time indexes to keep things in the same order
        int64_t nNow = (GetTime() - 1) * 1000000;
        static int64_t nLastTime;
        ++nLastTime;
        nNow = std::max(nNow, nLastTime);
        nLastTime = nNow;

        // Each retry is 2 minutes after the last
        nRequestTime = std::max(nRequestTime + 2 * 60 * 1000000, nNow);
        mapAskFor.insert(std::make_pair(nRequestTime, inv));
    }

    void BeginMessage(const char* pszCommand)
    {
        ENTER_CRITICAL_SECTION(cs_vSend);
        if (nHeaderStart != -1)
            AbortMessage();
        nHeaderStart = (int32_t)vSend.size();
        vSend << CMessageHeader(pszCommand, 0);
        nMessageStart = (uint32_t)vSend.size();
        if (fDebug)
            printf("sending: %s ", pszCommand);
    }

    void AbortMessage()
    {
        if (nHeaderStart < 0)
            return;
        vSend.resize(nHeaderStart);
        nHeaderStart = -1;
        nMessageStart = std::numeric_limits<uint32_t>::max();
        LEAVE_CRITICAL_SECTION(cs_vSend);

        if (fDebug)
            printf("(aborted)\n");
    }

    void EndMessage();

    void EndMessageAbortIfEmpty()
    {
        if (nHeaderStart < 0)
            return;
        int nSize = (int) vSend.size() - nMessageStart;
        if (nSize > 0)
            EndMessage();
        else
            AbortMessage();
    }

    void PushVersion();

    template<typename ...Args>
    void PushMessage(const char* pszCommand, const Args&... args)
    {
        try
        {
            BeginMessage(pszCommand);
            if constexpr (sizeof...(Args) > 0)
                (vSend << ... << args);
            EndMessage();
        }
        catch (...)
        {
            AbortMessage();
            throw;
        }
    }

    void PushGetBlocks(CBlockIndex* pindexBegin, uint256 hashEnd);
    bool IsSubscribed(unsigned int nChannel);
    void Subscribe(unsigned int nChannel, unsigned int nHops=0);
    void CancelSubscribe(unsigned int nChannel);
    void CloseSocketDisconnect();
    void Cleanup();


    // Denial-of-service detection/prevention
    // The idea is to detect peers that are behaving
    // badly and disconnect/ban them, but do it in a
    // one-coding-mistake-won't-shatter-the-entire-network
    // way.
    // IMPORTANT:  There should be nothing I can give a
    // node that it will forward on that will make that
    // node's peers drop it. If there is, an attacker
    // can isolate a node and/or try to split the network.
    // Dropping a node for sending stuff that is invalid
    // now but might be valid in a later version is also
    // dangerous, because it can cause a network split
    // between nodes running old code and nodes running
    // new code.
    static void ClearBanned(); // needed for unit testing
    static bool IsBanned(CNetAddr ip);
    bool Misbehaving(int howmuch); // 1 == a little, 100 == a lot
    void copyStats(CNodeStats &stats);
    // Network stats
    static void RecordBytesRecv(uint64_t bytes);
    static void RecordBytesSent(uint64_t bytes);

    static uint64_t GetTotalBytesRecv();
    static uint64_t GetTotalBytesSent();
};

class CTransaction;
void RelayTransaction(const CTransaction& tx, const uint256& hash);
void RelayTransaction(const CTransaction& tx, const uint256& hash, const CDataStream& ss);


/** Return a timestamp in the future (in microseconds) for exponentially distributed events. */
int64_t PoissonNextSend(int64_t nNow, int average_interval_seconds);

#endif