// Copyright (c) 2021-2024 The Hush developers
// Copyright (c) 2020-2023 The Freicoin Developers
// Copyright (c) 2021-2023 Decker
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.
// Stratum protocol:
//   - https://en.bitcoin.it/wiki/Stratum_mining_protocol - Stratum mining protocol
//   - https://github.com/slushpool/poclbm-zcash/wiki/Stratum-protocol-changes-for-ZCash - Stratum protocol changes for ZCash

#include "stratum.h"
#include "base58.h"
#include "chainparams.h"
#include "consensus/validation.h"
#include "crypto/sha256.h"
#include "httpserver.h"
#include "miner.h"
#include "netbase.h"
#include "net.h"
#include "rpc/server.h"
#include "serialize.h"
#include "streams.h"
#include "sync.h"
#include "txmempool.h"
#include "uint256.h"
#include "util.h"
#include "util/strencodings.h"
#include <univalue.h>
#include <algorithm> // for std::reverse
#include <string>
#include <vector>

#include <boost/algorithm/string.hpp> // for boost::trim
#include <boost/lexical_cast.hpp>
#include <boost/none.hpp>
#include <boost/optional.hpp>
#include <boost/thread.hpp>

#include <event2/event.h>
#include <event2/listener.h>
#include <event2/buffer.h>
#include <event2/bufferevent.h>

#include <errno.h>
#ifdef WIN32
#include <winsock2.h>
#else
#include <arpa/inet.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#endif

#include "main.h" // cs_main
#include <boost/foreach.hpp>
#include "ui_interface.h"
#include <memory> // make_unique

#include <locale>
#include <boost/date_time/posix_time/posix_time.hpp>

#include <chrono>
#include <thread>

// https://en.cppreference.com/w/cpp/types/integer - cinttypes for format constants, like PRId64, etc.
#include <cinttypes>


extern uint16_t ASSETCHAINS_RPCPORT; // don't want to include hush_globals.h
UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails = false); // rpc/blockchain.cpp
bool DecodeHexTx(CTransaction& tx, const std::string& strHexTx); // src/core_read.cpp

static const long jobRebroadcastTimeout = 30;
static const long txMemPoolCheckTimeout = 10;

/**
 * Begin of helper routines,
 * included: missed in httpserver.cpp in our codebase, missed
 * constructors for CSubNet(...), etc.
*/

namespace { // better to use anonymous namespace for helper routines

    class CStratumParams {
        private:
            const arith_uint256 defaultHashTarget;
            arith_uint256 currentHashTarget;
        public:
            CStratumParams() : defaultHashTarget(UintToArith256(uint256S("00ffff0000000000000000000000000000000000000000000000000000000000"))),
                            currentHashTarget(defaultHashTarget), fAllowLowDiffShares(false), fCheckEquihashSolution(true),
                            fstdErrDebugOutput(false) { }
            ~CStratumParams() {}

            void setTarget(const arith_uint256& target) { currentHashTarget = target; }
            arith_uint256 getTarget() { return currentHashTarget; }

            bool fAllowLowDiffShares;
            bool fCheckEquihashSolution;
            bool fstdErrDebugOutput;

    } instance_of_cstratumparams;

    /** Check if a network address is allowed to access the Stratum server */
    static bool ClientAllowed(const std::vector<CSubNet>& allowed_subnets, const CNetAddr& netaddr)
    {
        if (!netaddr.IsValid())
            return false;
        for(const CSubNet& subnet : allowed_subnets)
            if (subnet.Match(netaddr))
                return true;
        return false;
    }

    /** Initialize ACL list for Stratum server */
    static bool InitStratumAllowList(std::vector<CSubNet>& allowed_subnets)
    {
        allowed_subnets.clear();
    	CNetAddr localv4, localv6;
    	LookupHost("127.0.0.1", localv4, false);
    	LookupHost("::1", localv6, false);

        allowed_subnets.push_back(CSubNet(localv4, 8)); // always allow IPv4 local subnet
        allowed_subnets.push_back(CSubNet(localv6));         // always allow IPv6 localhost
        if (mapMultiArgs.count("-stratumallowip")) {
            const std::vector<std::string>& vAllow = mapMultiArgs["-stratumallowip"];
            for(const std::string& strAllow : vAllow) {
		CSubNet subnet;
    		LookupSubNet(strAllow.c_str(), subnet);
                if (!subnet.IsValid()) {
                    uiInterface.ThreadSafeMessageBox(
                        strprintf("Invalid -stratumallowip subnet specification: %s. Valid are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. 1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24).", strAllow),
                        "", CClientUIInterface::MSG_ERROR);
                    return false;
                }
                allowed_subnets.push_back(subnet);
            }
        }
        return true;
    }

   double GetDifficultyFromBits(uint32_t bits) {

        uint32_t powLimit = UintToArith256(Params().GetConsensus().powLimit).GetCompact();
        int nShift = (bits >> 24) & 0xff;
        int nShiftAmount = (powLimit >> 24) & 0xff;

        double dDiff =
            (double)(powLimit & 0x00ffffff) /
            (double)(bits & 0x00ffffff);

        while (nShift < nShiftAmount)
        {
            dDiff *= 256.0;
            nShift++;
        }
        while (nShift > nShiftAmount)
        {
            dDiff /= 256.0;
            nShift--;
        }

        return dDiff;
    }

    std::string DateTimeStrPrecise() // or we can use standart one, like DateTimeStrFormat("[%Y-%m-%d %H:%M:%S.%f]", GetTime())
    {
        // https://stackoverflow.com/questions/28136660/format-a-posix-time-with-just-3-digits-in-fractional-seconds
        // https://www.boost.org/doc/libs/1_35_0/doc/html/date_time/date_time_io.html#date_time.format_flags

        // std::locale takes ownership of the pointer
        boost::posix_time::ptime const date_time = boost::posix_time::microsec_clock::local_time();
        std::locale loc(std::locale::classic(), new boost::posix_time::time_facet("[%Y-%m-%d %H:%M:%S.%f] "));
        std::stringstream ss;
        ss.imbue(loc);
        // ss << boost::posix_time::from_time_t(nTime);
        ss << date_time;
        return ss.str();
    }

    std::string get_stripped_username(const std::string& username) {
        std::string res(username);
        size_t dotpos = username.find('.');
        if (dotpos != std::string::npos)
            res.resize(dotpos);
        return res;
    }

    // C++11 map initialization
    const std::map<std::string,std::string> mapColors = {
        { "cl_N",  "\x1B[0m"  },
        { "cl_RED",  "\x1B[31m" },
        { "cl_GRN",  "\x1B[32m" },
        { "cl_YLW",  "\x1B[33m" },
        { "cl_BLU",  "\x1B[34m" },
        { "cl_MAG",  "\x1B[35m" },
        { "cl_CYN",  "\x1B[36m" },
        { "cl_BLK",  "\x1B[22;30m" }, /* black */
        { "cl_RD2",  "\x1B[22;31m" }, /* red */
        { "cl_GR2",  "\x1B[22;32m" }, /* green */
        { "cl_YL2",  "\x1B[22;33m" }, /* dark yellow */
        { "cl_BL2",  "\x1B[22;34m" }, /* blue */
        { "cl_MA2",  "\x1B[22;35m" }, /* magenta */
        { "cl_CY2",  "\x1B[22;36m" }, /* cyan */
        { "cl_SIL",  "\x1B[22;37m" }, /* gray */
        { "cl_LRD",  "\x1B[01;31m" }, /* light red */
        { "cl_LGR",  "\x1B[01;32m" }, /* light green */
        { "cl_LYL",  "\x1B[01;33m" }, /* tooltips */
        { "cl_LBL",  "\x1B[01;34m" }, /* light blue */
        { "cl_LMA",  "\x1B[01;35m" }, /* light magenta */
        { "cl_LCY",  "\x1B[01;36m" }, /* light cyan */
        { "cl_WHT",  "\x1B[01;37m" }, /* white */
    };

    enum ColorType
    {
        cl_N, cl_RED, cl_GRN, cl_YLW, cl_BLU, cl_MAG, cl_CYN, cl_BLK, cl_RD2, cl_GR2, cl_YL2, cl_BL2, cl_MA2, cl_CY2, cl_SIL, cl_LRD, cl_LGR, cl_LYL, cl_LBL, cl_LMA, cl_LCY, cl_WHT
    };

    char const* ColorTypeNames[]=
    {
        "\x1B[0m"    , "\x1B[31m"   , "\x1B[32m"   , "\x1B[33m"   , "\x1B[34m"   ,
        "\x1B[35m"   , "\x1B[36m"   , "\x1B[22;30m", "\x1B[22;31m", "\x1B[22;32m",
        "\x1B[22;33m", "\x1B[22;34m", "\x1B[22;35m", "\x1B[22;36m", "\x1B[22;37m",
        "\x1B[01;31m", "\x1B[01;32m", "\x1B[01;33m", "\x1B[01;34m", "\x1B[01;35m",
        "\x1B[01;36m", "\x1B[01;37m"
    };
}

namespace ccminer {

    bool hex2bin(void *output, const char *hexstr, size_t len)
    {
        unsigned char *p = (unsigned char *) output;
        char hex_byte[4];
        char *ep;

        hex_byte[2] = '\0';

        while (*hexstr && len) {
            if (!hexstr[1]) {
                LogPrint("stratum", "hex2bin str truncated");
                return false;
            }
            hex_byte[0] = hexstr[0];
            hex_byte[1] = hexstr[1];
            *p = (unsigned char) strtol(hex_byte, &ep, 16);
            if (*ep) {
                LogPrint("stratum", "hex2bin failed on '%s'", hex_byte);
                return false;
            }
            p++;
            hexstr += 2;
            len--;
        }

        return (len == 0 && *hexstr == 0) ? true : false;
    }

    // equi/equi-stratum.cpp
    double target_to_diff_equi(uint32_t* target)
    {
        unsigned char* tgt = (unsigned char*) target;
        uint64_t m =
            (uint64_t)tgt[30] << 24 |
            (uint64_t)tgt[29] << 16 |
            (uint64_t)tgt[28] << 8  |
            (uint64_t)tgt[27] << 0;

        if (!m)
            return 0.;
        else
            return (double)0xffff0000UL/m;
    }

    void diff_to_target_equi(uint32_t *target, double diff)
    {
        uint64_t m;
        int k;

        for (k = 6; k > 0 && diff > 1.0; k--)
            diff /= 4294967296.0;
        m = (uint64_t)(4294901760.0 / diff);
        if (m == 0 && k == 6)
            memset(target, 0xff, 32);
        else {
            memset(target, 0, 32);
            target[k + 1] = (uint32_t)(m >> 8);
            target[k + 2] = (uint32_t)(m >> 40);
            //memset(target, 0xff, 6*sizeof(uint32_t));
            for (k = 0; k < 28 && ((uint8_t*)target)[k] == 0; k++)
                ((uint8_t*)target)[k] = 0xff;
        }
    }

    void hush_diff_to_target_equi(uint32_t *target, double diff)
    {
        uint64_t m;
        int k;

        for (k = 6; k > 0 && diff > 1.0; k--)
            diff /= (double)((uint64_t)0x100000000);
        m = (uint64_t)((uint64_t)0x0f0f0f0f / diff);
        if (m == 0 && k == 6)
            memset(target, 0xff, 32);
        else {
            memset(target, 0, 32);
            target[k + 1] = (uint32_t)(m >> 8);
            target[k + 2] = (uint32_t)(m >> 40);
            //memset(target, 0xff, 6*sizeof(uint32_t));

            for (k = 0; k < 28 && ((uint8_t*)target)[k] == 0; k++)
                ((uint8_t*)target)[k] = 0xff;
            for (k = 0; k < 32; k++) ((uint8_t*)target)[31-k] = ((uint8_t*)target)[31-k-1];
            ((uint8_t*)target)[0] = 0xff;
        }
    }

    /* compute nbits to get the network diff */
    double equi_network_diff(uint32_t nbits)
    {
        //HUSH bits: "1e 015971",
        //HUSH target: "00 00 015971000000000000000000000000000000000000000000000000000000",
        //HUSH bits: "1d 686aaf",
        //HUSH target: "00 0000 686aaf0000000000000000000000000000000000000000000000000000",
        // uint32_t nbits = work->data[26];

        uint32_t bits = (nbits & 0xffffff);
        int16_t shift = (/*swab32*/bswap_32(nbits) & 0xff);
        shift = (31 - shift) * 8; // 8 bits shift for 0x1e, 16 for 0x1d
        uint64_t tgt64 = /*swab32*/bswap_32(bits);
        tgt64 = tgt64 << shift;
        // applog_hex(&tgt64, 8);
        uint8_t net_target[32] = { 0 };
        for (int b=0; b<8; b++)
            net_target[31-b] = ((uint8_t*)&tgt64)[b];
        // applog_hex(net_target, 32);
        double d = target_to_diff_equi((uint32_t*)net_target);
        return d;
    }

    double equi_stratum_target_to_diff(const std::string& target)
    {
        uint8_t target_bin[32], target_be[32];

        const char *target_hex = target.c_str();
        if (!target_hex || strlen(target_hex) == 0)
            return false;

        hex2bin(target_bin, target_hex, 32);
        memset(target_be, 0xff, 32);
        int filled = 0;
        for (int i=0; i<32; i++) {
            if (filled == 3) break;
            target_be[31-i] = target_bin[i];
            if (target_bin[i]) filled++;
        }

        double d = target_to_diff_equi((uint32_t*) &target_be);
        return d;
    }

    /* Subtract the `struct timeval' values X and Y,
       storing the result in RESULT.
       Return 1 if the difference is negative, otherwise 0.  */
    int timeval_subtract(struct timeval *result, struct timeval *x,
        struct timeval *y)
    {
        /* Perform the carry for the later subtraction by updating Y. */
        if (x->tv_usec < y->tv_usec) {
            int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
            y->tv_usec -= 1000000 * nsec;
            y->tv_sec += nsec;
        }
        if (x->tv_usec - y->tv_usec > 1000000) {
            int nsec = (x->tv_usec - y->tv_usec) / 1000000;
            y->tv_usec += 1000000 * nsec;
            y->tv_sec -= nsec;
        }

        /* Compute the time remaining to wait.
        * `tv_usec' is certainly positive. */
        result->tv_sec = x->tv_sec - y->tv_sec;
        result->tv_usec = x->tv_usec - y->tv_usec;

        /* Return 1 if result is negative. */
        return x->tv_sec < y->tv_sec;
    }

}

/**
 * End of helper routines
*/

struct StratumClient
{
    evconnlistener* m_listener;
    evutil_socket_t m_socket;
    bufferevent* m_bev;
    CService m_from;
    int m_nextid;
    uint256 m_secret;

    CService GetPeer() const
      { return m_from; }

    std::string m_client;

    bool m_authorized;
    CBitcoinAddress m_addr;
    double m_mindiff;

    uint32_t m_version_rolling_mask;

    CBlockIndex* m_last_tip;
    bool m_second_stage;
    bool m_send_work;

    bool m_supports_aux;
    std::set<CBitcoinAddress> m_aux_addr;

    bool m_supports_extranonce;

    StratumClient() : m_listener(0), m_socket(0), m_bev(0), m_nextid(0), m_authorized(false), m_mindiff(0.0), m_version_rolling_mask(0x00000000), m_last_tip(0), m_second_stage(false), m_send_work(false), m_supports_aux(false), m_supports_extranonce(false) { GenSecret(); }
    StratumClient(evconnlistener* listener, evutil_socket_t socket, bufferevent* bev, CService from) : m_listener(listener), m_socket(socket), m_bev(bev), m_nextid(0), m_from(from), m_authorized(false), m_mindiff(0.0), m_version_rolling_mask(0x00000000), m_last_tip(0), m_second_stage(false), m_send_work(false), m_supports_aux(false), m_supports_extranonce(false) { GenSecret(); }

    void GenSecret();
    std::vector<unsigned char> ExtraNonce1(uint256 job_id) const;
};

void StratumClient::GenSecret()
{
    GetRandBytes(m_secret.begin(), 32);
}

std::vector<unsigned char> StratumClient::ExtraNonce1(uint256 job_id) const
{
    CSHA256 nonce_hasher;
    nonce_hasher.Write(m_secret.begin(), 32);

    if (m_supports_extranonce) {
        nonce_hasher.Write(job_id.begin(), 32);
    }

    uint256 job_nonce;
    nonce_hasher.Finalize(job_nonce.begin());
    return {job_nonce.begin(), job_nonce.begin()+8};
}

struct StratumWork {
    CBlockTemplate m_block_template;
    // First we generate the segwit commitment for the miner's coinbase with
    // ComputeFastMerkleBranch.
    std::vector<uint256> m_cb_wit_branch;
    // Then we compute the initial right-branch for the block-tx Merkle tree
    // using ComputeStableMerkleBranch...
    std::vector<uint256> m_bf_branch;
    // ...which is appended to the end of m_cb_branch so we can compute the
    // block's hashMerkleRoot with ComputeMerkleBranch.
    std::vector<uint256> m_cb_branch;
    bool m_is_witness_enabled;

    int32_t nHeight;
    std::string local_diff;

    // The cached 2nd-stage auxiliary hash value, if an auxiliary proof-of-work
    // solution has been found.
    boost::optional<uint256> m_aux_hash2;

    StratumWork() : m_is_witness_enabled(false),nHeight(0) { };
    StratumWork(const CBlockTemplate& block_template, bool is_witness_enabled);

    CBlock& GetBlock()
      { return m_block_template.block; }
    const CBlock& GetBlock() const
      { return m_block_template.block; }
};

StratumWork::StratumWork(const CBlockTemplate& block_template, bool is_witness_enabled)
    : m_block_template(block_template)
    , m_is_witness_enabled(is_witness_enabled), nHeight(0)
{
    // Generate the block-witholding secret for the work unit.

    std::vector<uint256> leaves;
    for (const auto& tx : m_block_template.block.vtx) {
        leaves.push_back(tx.GetHash());
    }

    std::vector<uint256> vMerkleTree; uint256 merkleRoot; bool fMutated;

    merkleRoot = BuildMerkleTree(&fMutated, leaves, vMerkleTree);
    m_cb_branch = GetMerkleBranch(0, leaves.size(), vMerkleTree);
    // m_cb_branch = ComputeMerkleBranch(leaves, 0);
};

//! Critical seciton guarding access to any of the stratum global state
static CCriticalSection cs_stratum;

//! List of subnets to allow stratum connections from
static std::vector<CSubNet> stratum_allow_subnets;

//! Bound stratum listening sockets
static std::map<evconnlistener*, CService> bound_listeners;

//! Active miners connected to us
static std::map<bufferevent*, StratumClient> subscriptions;

//! Mapping of stratum method names -> handlers
static std::map<std::string, boost::function<UniValue(StratumClient&, const UniValue&)> > stratum_method_dispatch;

//! A mapping of job_id -> work templates
static std::map<uint256, StratumWork> work_templates;

//! The job_id of the first work unit to have its auxiliary proof-of-work solved
//! for the current block, or boost::none if no solution has been returned yet.
static boost::optional<uint256> half_solved_work;

//! A thread to watch for new blocks and send mining notifications
static boost::thread block_watcher_thread;

std::string HexInt4(uint32_t val)
{
    std::vector<unsigned char> vch;
    vch.push_back((val >> 24) & 0xff);
    vch.push_back((val >> 16) & 0xff);
    vch.push_back((val >>  8) & 0xff);
    vch.push_back( val        & 0xff);
    return HexStr(vch);
}

uint32_t ParseHexInt4(const UniValue& hex, const std::string& name)
{
    std::vector<unsigned char> vch = ParseHexV(hex, name);
    if (vch.size() != 4) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, name+" must be exactly 4 bytes / 8 hex");
    }
    uint32_t ret = 0;
    ret |= vch[0] << 24;
    ret |= vch[1] << 16;
    ret |= vch[2] <<  8;
    ret |= vch[3];
    return ret;
}

uint256 ParseUInt256(const UniValue& hex, const std::string& name)
{
    if (!hex.isStr()) {
        throw std::runtime_error(name+" must be a hexidecimal string");
    }
    std::vector<unsigned char> vch = ParseHex(hex.get_str());
    if (vch.size() != 32) {
        throw std::runtime_error(name+" must be exactly 32 bytes / 64 hex");
    }
    uint256 ret;
    std::copy(vch.begin(), vch.end(), ret.begin());
    return ret;
}

static double ClampDifficulty(const StratumClient& client, double diff)
{
    if (client.m_mindiff > 0) {
        diff = client.m_mindiff;
    }
    diff = std::max(diff, 0.001);
    return diff;
}

static std::string GetExtraNonceRequest(StratumClient& client, const uint256& job_id)
{
    // https://en.bitcoin.it/wiki/Stratum_mining_protocol#mining.set_extranonce
    // mining.set_extranonce("extranonce1", extranonce2_size)

    std::string ret;
    if (client.m_supports_extranonce)
    {
        std::vector<unsigned char> extranonce1 = client.ExtraNonce1(job_id);

        const std::string k_extranonce_req = std::string()
            + "{"
            +     "\"id\":";
        const std::string k_extranonce_req2 = std::string()
            +     ","
            +     "\"method\":\"mining.set_extranonce\","
            +     "\"params\":["
            +         "\"";
        const std::string k_extranonce_req3 = std::string()
            +            "\","                                 // extranonce1
            +         strprintf("%d", 32 - extranonce1.size()) // extranonce2.size() = 32 - extranonce1.size()
            +     "]"
            + "}"
            + "\n";

        ret = k_extranonce_req
            + strprintf("%d", client.m_nextid++)
            + k_extranonce_req2
            + HexStr(extranonce1)
            + k_extranonce_req3;
    }
    return ret;
}

/**
 * @brief
 *
 * @param client
 * @param current_work
 * @param addr
 * @param extranonce1
 * @param extranonce2
 * @param cb
 * @param bf
 * @param cb_branch
 */
void CustomizeWork(const StratumClient& client, const StratumWork& current_work, const CBitcoinAddress& addr, const std::vector<unsigned char>& extranonce1, const std::vector<unsigned char>& extranonce2, CMutableTransaction& cb, CMutableTransaction& bf, std::vector<uint256>& cb_branch)
{
    if (current_work.GetBlock().vtx.empty()) {
        const std::string msg = strprintf("%s: no transactions in block template; unable to submit work", __func__);
        LogPrint("stratum", "%s\n", msg);
        throw std::runtime_error(msg);
    }

    cb = CMutableTransaction(current_work.GetBlock().vtx[0]);

    if (cb.vin.size() != 1) {
        const std::string msg = strprintf("%s: unexpected number of inputs; is this even a coinbase transaction?", __func__);
        LogPrint("stratum", "%s\n", msg);
        throw std::runtime_error(msg);
    }

    std::vector<unsigned char> nonce(extranonce1);

    if ((nonce.size() + extranonce2.size()) != 32) {
        const std::string msg = strprintf("%s: unexpected combined nonce length: extranonce1(%d) + extranonce2(%d) != 32; unable to submit work", __func__, nonce.size(), extranonce2.size());
        LogPrint("stratum", "%s\n", msg);
        throw std::runtime_error(msg);
    }
    nonce.insert(nonce.end(), extranonce2.begin(), extranonce2.end());

    // nonce = extranonce1 + extranonce2
    // if (instance_of_cstratumparams.fstdErrDebugOutput) {
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " nonce = " << HexStr(nonce) << std::endl;
    // }

    if (cb.vin.empty()) {
        const std::string msg = strprintf("%s: first transaction is missing coinbase input; unable to customize work to miner", __func__);
        LogPrint("stratum", "%s\n", msg);
        throw std::runtime_error(msg);
    }
    // cb.vin[0].scriptSig =
    //        CScript()
    //     << cb.lock_height
    //     << nonce;

    /* actually we will change only cb destination on the miner address */
    {
        if (cb.vout.empty()) {
            const std::string msg = strprintf("%s: coinbase transaction is missing outputs; unable to customize work to miner", __func__);
            LogPrint("stratum", "%s\n", msg);
            throw std::runtime_error(msg);
        }
        if (cb.vout[0].scriptPubKey == (CScript() << OP_FALSE)) {
            cb.vout[0].scriptPubKey = GetScriptForDestination(addr.Get());
        }
    }

    // cb_branch = current_work.m_cb_branch;
}

std::string GetWorkUnit(StratumClient& client)
{
    // LOCK(cs_main);

    /* if (!g_connman) {
        throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
    } */

    /* if (!Params().MineBlocksOnDemand() && g_connman->GetNodeCount(CConnman::CONNECTIONS_ALL) == 0) {
        throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Hush is not connected!");
    } */

    bool fvNodesEmpty;
    {
        LOCK(cs_vNodes);
        fvNodesEmpty = vNodes.empty();
    }

    if (Params().MiningRequiresPeers() && fvNodesEmpty)
    {
        const std::string msg = strprintf("%s: Unable to get work unit, Hush is not connected!", __func__);
        LogPrint("stratum", "%s\n", msg);
        throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Hush is not connected!");
    }

    if (IsInitialBlockDownload()) {
        const std::string msg = strprintf("%s: Unable to get work unit, Hush is still downloading blocks!", __func__);
        LogPrint("stratum", "%s\n", msg);
        throw JSONRPCError(RPC_CLIENT_IN_INITIAL_DOWNLOAD, "Hush is downloading blocks...");
    }

    if (!client.m_authorized && client.m_aux_addr.empty()) {
        const std::string msg = strprintf("%s: Unable to get work unit, client not authorized! Use address 'x' to mine to the default address", __func__);
        LogPrint("stratum", "%s\n", msg);
        throw JSONRPCError(RPC_INVALID_REQUEST, "Stratum client not authorized.  Use mining.authorize first, with a Hush R.. address as the username or 'x' to mine to the default address.");
    }

    static CBlockIndex* tip = NULL; // pindexPrev
    static uint256 job_id;
    static unsigned int transactions_updated_last = 0;
    static int64_t last_update_time = 0;

    // rpc/mining.cpp -> getblocktemplate -> Update block
    if ( tip != chainActive.Tip() ||
        (mempool.GetTransactionsUpdated() != transactions_updated_last && (GetTime() - last_update_time) > 5) ||
        !work_templates.count(job_id))
    {
        CBlockIndex *tip_new = chainActive.Tip();

        /**
         * We will check script later inside CustomizeWork, if it will be == CScript() << OP_FALSE it will mean
         * that work need to be customized, and in that case cb.vout[0].scriptPubKey will be set to GetScriptForDestination(addr.Get()) .
         * In other words to the address with which stratum client is authorized.
        */
        const CScript scriptDummy = CScript() << OP_FALSE;
        std::unique_ptr<CBlockTemplate> new_work(CreateNewBlock(CPubKey(), scriptDummy, HUSH_MAXGPUCOUNT, false)); // std::unique_ptr<CBlockTemplate> new_work = BlockAssembler(Params()).CreateNewBlock(script);

        /* test values for debug */
        // new_work->block.nBits = 0x200f0f0f;
        // new_work->block.nTime = 1623567886;
        // new_work->block.hashPrevBlock = uint256S("027e3758c3a65b12aa1046462b486d0a63bfa1beae327897f56c5cfb7daaae71");
        // new_work->block.hashMerkleRoot = uint256S("29f0e769c762b691d81d31bbb603719a94ef04d53d332f7de5e5533ddfd08e19");
        // new_work->block.hashFinalSaplingRoot = uint256S("3e49b5f954aa9d3545bc6c37744661eea48d7c34e3000d82b7f0010c30f4c2fb");
        // DecodeHexTx(new_work->block.vtx[0], "01000000010000000000000000000000000000000000000000000000000000000000000000ffffffff03510101ffffffff01aa2ce73b0000000023210325b4ca6736f90679f712be1454c5302050aae6edb51b0d2a051156bc868fec16ac4aabc560");

        if (!new_work) {
            const std::string msg = strprintf("%s: Out of memory!", __func__);
            LogPrint("stratum", "%s\n", msg);
            throw JSONRPCError(RPC_OUT_OF_MEMORY, "Out of memory");
        }

        // if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << "hashMerkleRoot = " << new_work->block.hashMerkleRoot.ToString() << std::endl;

        // So that block.GetHash() is correct
        //new_work->block.hashMerkleRoot = BlockMerkleRoot(new_work->block);
        new_work->block.hashMerkleRoot = new_work->block.BuildMerkleTree();

        // NB! here we have merkle with scriptDummy script in coinbase, after CustomizeWork we should recalculate it (!)
        // if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << "hashMerkleRoot = " << new_work->block.hashMerkleRoot.ToString() << std::endl;

        job_id = new_work->block.GetHash();
        //work_templates[job_id] = StratumWork(*new_work, new_work->block.vtx[0]->HasWitness());
        work_templates[job_id] = StratumWork(*new_work, false);

        tip = tip_new;

        transactions_updated_last = mempool.GetTransactionsUpdated();
        last_update_time = GetTime();

        LogPrint("stratum", "New stratum block template (%d total): %s\n", work_templates.size(), HexStr(job_id.begin(), job_id.end()));

        // Remove any old templates
        std::vector<uint256> old_job_ids;
        boost::optional<uint256> oldest_job_id = boost::none;
        uint32_t oldest_job_nTime = last_update_time;
        for (const auto& work_template : work_templates) {
            // If, for whatever reason the new work was generated with
            // an old nTime, don't erase it!
            if (work_template.first == job_id) {
                continue;
            }
            // Build a list of outdated work units to free.
            if (work_template.second.GetBlock().nTime < (last_update_time - 900)) {
                old_job_ids.push_back(work_template.first);
            }
            // Track the oldest work unit, in case we have too much
            // recent work.
            if (work_template.second.GetBlock().nTime <= oldest_job_nTime) {
                oldest_job_id = work_template.first;
                oldest_job_nTime = work_template.second.GetBlock().nTime;
            }
        }
        // Remove all outdated work.
        for (const auto& old_job_id : old_job_ids) {
            work_templates.erase(old_job_id);
            LogPrint("stratum", "Removed outdated stratum block template (%d total): %s\n", work_templates.size(), HexStr(old_job_id.begin(), old_job_id.end()));
        }
        // Remove the oldest work unit if we're still over the maximum
        // number of stored work templates.
        if (work_templates.size() > 30 && oldest_job_id) {
            work_templates.erase(oldest_job_id.get());
            LogPrint("stratum", "Removed oldest stratum block template (%d total): %s\n", work_templates.size(), HexStr(oldest_job_id.get().begin(), oldest_job_id.get().end()));
        }
    }

    StratumWork& current_work = work_templates[job_id];


    CBlockIndex tmp_index;

    // Native proof-of-work difficulty
    tmp_index.nBits = current_work.GetBlock().nBits;
    double diff = ClampDifficulty(client, GetDifficulty(&tmp_index));

    UniValue set_target(UniValue::VOBJ);
    set_target.push_back(Pair("id", client.m_nextid++));
    set_target.push_back(Pair("method", "mining.set_target"));
    UniValue set_target_params(UniValue::VARR);

    std::string strTarget; // set_target
    {
        arith_uint256 hashTarget; bool fNegative,fOverflow;
        /*

        // Targets Table Example: hush diff and ccminer diff are different (!),
        // Hush diff = NiceHash diff, ccminer_diff = Yiimp diff.

        hashTarget.SetCompact(HUSH_MINDIFF_NBITS,&fNegative,&fOverflow); // blkhdr.nBits
        hashTarget = UintToArith256(uint256S("0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f"));
        hashTarget.SetHex("0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f");

        hashTarget.SetHex("00ffff0000000000000000000000000000000000000000000000000000000000"); // hush_diff = 15.0591, ccminer_diff = 1
        hashTarget.SetHex("003fffc000000000000000000000000000000000000000000000000000000000"); // hush_diff = 60.2362, ccminer_diff = 4
        hashTarget.SetHex("0007fff800000000000000000000000000000000000000000000000000000000"); // hush_diff = 481.89, ccminer_diff = 31.9999
        hashTarget.SetHex("c7ff3800ffffffffffffffffffffffffffffffffffffffffffffffffffffffff"); // hush_diff = 0.0752956, ccminer_diff = 1.00303
        hashTarget.SetHex("0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f"); // hush_diff = 1, ccminer_diff = 16.9956
        */

        arith_uint256 aHashTarget = instance_of_cstratumparams.getTarget();

        // arith_uint256 aHashTarget = UintToArith256(uint256S("00ffff0000000000000000000000000000000000000000000000000000000000")); // 1.0
        // aHashTarget = aHashTarget / 8704; // hush_diff = 131074 (NiceHash), ccminer_diff = 8704 (Yiimp)

        /* here we can adjust diff by some algo, note that 00ffff0000000000000000000000000000000000000000000000000000000000 / 8704 =
           0000078780000000000000000000000000000000000000000000000000000000, which is equivalent to hush_diff = 131074 (NiceHash),
           ccminer_diff = 8704 (Yiimp)
        */

        hashTarget = aHashTarget;
        strTarget = hashTarget.GetHex();
        current_work.local_diff = strTarget;

        if (instance_of_cstratumparams.fstdErrDebugOutput) {
            std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ <<
                    strprintf(" target = %s, hush_diff = %g, ccminer_diff = %g",
                    strTarget, GetDifficultyFromBits(hashTarget.GetCompact(false)), ccminer::equi_stratum_target_to_diff(strTarget)) << std::endl;
        }
    }

    set_target_params.push_back(UniValue(strTarget)); // TODO: send real local diff (!)
    set_target.push_back(Pair("params", set_target_params));

    CMutableTransaction cb, bf;
    std::vector<uint256> cb_branch;

    // if (instance_of_cstratumparams.fstdErrDebugOutput)
    // {
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " [1] cb = " << CTransaction(cb).ToString() << std::endl;
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " [1] current_work.GetBlock().vtx[0] = " << current_work.GetBlock().vtx[0].ToString() << std::endl;
    // }

    {
        std::vector<unsigned char> extranonce1 = client.ExtraNonce1(job_id);

        static const std::vector<unsigned char> dummy(32-extranonce1.size(), 0x00); // extranonce2
        CustomizeWork(client, current_work, client.m_addr, extranonce1, dummy, cb, bf, cb_branch);

        // without 2 lines below equihash solutinon on SubmitWork will be incorrect, bcz we should
        // change vtx[0] in current work and re-calc hashMerkleRoot
        // TODO: refactor all of these ... may be change this in current_work directly is bad idea,
        // and we should do all checks and hashMerkleRoot at SubmitBlock(...)

        current_work.GetBlock().vtx[0] = cb;
        current_work.GetBlock().hashMerkleRoot = current_work.GetBlock().BuildMerkleTree();

    }

    // if (instance_of_cstratumparams.fstdErrDebugOutput)
    // {
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " [2] cb = " << CTransaction(cb).ToString() << std::endl;
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " [2] current_work.GetBlock().vtx[0] = " << current_work.GetBlock().vtx[0].ToString() << std::endl;
    // }

    CBlockHeader blkhdr;
    // Setup native proof-of-work

    blkhdr = current_work.GetBlock().GetBlockHeader(); // copy entire blockheader created with CreateNewBlock to blkhdr
    // CDataStream ds(SER_GETHASH, SERIALIZE_TRANSACTION_NO_WITNESS);
    CDataStream ds(SER_GETHASH, PROTOCOL_VERSION);
    ds << cb;

    /*
        HexInt4(blkhdr.nVersion) = 00000004, so we can't use it here, will use swab conversion via 1 of 3 methods:

        (1) params.push_back(HexStr((unsigned char *)&blkhdr.nVersion, (unsigned char *)&blkhdr.nVersion + sizeof(blkhdr.nVersion))); // VERSION
        (2) std::vector<unsigned char> vnVersion(4, 0);
            WriteLE64(&vnVersion[0], blkhdr.nVersion);
            params.push_back(HexStr(vnVersion));
        (3) params.push_back(HexInt4(bswap_32(blkhdr.nVersion)));

            Bytes order, cheatsheet:

            [ need ] fbc2f4300c01f0b7820d00e3347c8da4ee614674376cbc45359daa54f9b5493e - HexStr(ToByteVector(blkhdr.hashFinalSaplingRoot))
            [ need ] fbc2f4300c01f0b7820d00e3347c8da4ee614674376cbc45359daa54f9b5493e - HexStr(blkhdr.hashFinalSaplingRoot)
            [ ---- ] 3e49b5f954aa9d3545bc6c37744661eea48d7c34e3000d82b7f0010c30f4c2fb - blkhdr.hashFinalSaplingRoot.GetHex()
            [ ---- ] 3e49b5f954aa9d3545bc6c37744661eea48d7c34e3000d82b7f0010c30f4c2fb - blkhdr.hashFinalSaplingRoot.ToString()
    */

    /* mining.notify params */
    UniValue params(UniValue::VARR); // mining.notify params
    params.push_back(HexStr(job_id.begin(), job_id.end())); // JOB_ID
    params.push_back(HexInt4(bswap_32(blkhdr.nVersion))); // VERSION (0x4 -> "04000000")
    params.push_back(HexStr(blkhdr.hashPrevBlock));  // PREVHASH
    params.push_back(HexStr(blkhdr.hashMerkleRoot)); // MERKLEROOT
    params.push_back(HexStr(blkhdr.hashFinalSaplingRoot)); // RESERVED -> hashFinalSaplingRoot

    UpdateTime(&blkhdr, Params().GetConsensus(), tip /* or pindexPrev [tip-1] is needed? */);
    // blkhdr.nTime = GetTime();

    params.push_back(HexInt4(bswap_32(blkhdr.nTime))); // TIME
    params.push_back(HexInt4(bswap_32(blkhdr.nBits))); // BITS

    // Clean Jobs. If true, miners should abort their current work and immediately use the new job.
    // If false, they can still use the current job, but should move to the new one after exhausting the current nonce range.

    UniValue clean_jobs(UniValue::VBOOL);
    clean_jobs = client.m_last_tip != tip;
    params.push_back(clean_jobs); // CLEAN_JOBS

    if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << "New job: " << HexStr(job_id) << " " << strprintf("%08x", blkhdr.nTime) << std::endl;

    client.m_last_tip = tip;

    UniValue mining_notify(UniValue::VOBJ);
    mining_notify.push_back(Pair("id", client.m_nextid++));
    mining_notify.push_back(Pair("method", "mining.notify"));
    mining_notify.push_back(Pair("params", params));

    return GetExtraNonceRequest(client, job_id)
         + set_target.write() + "\n"
         + mining_notify.write()  + "\n";
}
bool SubmitBlock(StratumClient& client, const uint256& job_id, const StratumWork& current_work,
                 const std::vector<unsigned char>& extranonce1, const std::vector<unsigned char>& extranonce2,
                 boost::optional<uint32_t> nVersion, uint32_t nTime, const std::vector<unsigned char>& sol)
{
    // called from stratum_mining_submit and uses following data, came from client:
    // ["WORKER_NAME", "JOB_ID", "TIME", "NONCE_2", "EQUIHASH_SOLUTION"]
    // all other params we have saved in other places

    if (extranonce1.size() + extranonce2.size() != 32) {
        std::string msg = strprintf("extranonce1 [%d] length + extranonce2 [%d] length != %d", extranonce1.size(), extranonce2.size(), 32);
        LogPrint("stratum", "%s\n", msg);
        throw JSONRPCError(RPC_INVALID_PARAMETER, msg);
    }

    // TODO: change hardcoded constants on actual determine of solution size, depends on equihash algo type: 200.9, etc.
    if (sol.size() != 1347) {
        std::string msg = strprintf("%s: solution is wrong length (received %d bytes; expected %d bytes", __func__, extranonce2.size(), 1347);
        LogPrint("stratum", "%s\n", msg);
        throw JSONRPCError(RPC_INVALID_PARAMETER, msg);
    }

    CMutableTransaction cb, bf;
    std::vector<uint256> cb_branch;
    CustomizeWork(client, current_work, client.m_addr, extranonce1, extranonce2, cb, bf, cb_branch);

    bool res = false;
    {
        // Check native proof-of-work
        uint32_t version = current_work.GetBlock().nVersion;

        if (nVersion) version = *nVersion;
        CBlockHeader blkhdr(current_work.GetBlock());

        blkhdr.nVersion = version;
        blkhdr.hashPrevBlock = current_work.GetBlock().hashPrevBlock;
        // blkhdr.hashMerkleRoot = ComputeMerkleRootFromBranch(cb.GetHash(), cb_branch, 0);
        // blkhdr.hashMerkleRoot = blkhdr.BuildMerkleTree();
        blkhdr.nTime = nTime;
        blkhdr.nBits = current_work.GetBlock().nBits;

        // just an example of how-to reverse the things, don't needed in real life
        // std::vector<unsigned char> noncerev(extranonce1);
        // std::reverse(noncerev.begin(), noncerev.end());
        // noncerev.insert(noncerev.begin(), extranonce2.rbegin(), extranonce2.rend());

        std::vector<unsigned char> nonce(extranonce1);
        nonce.insert(nonce.end(), extranonce2.begin(), extranonce2.end());

        blkhdr.nSolution = std::vector<unsigned char>(sol.begin() + 3, sol.end());

        blkhdr.hashFinalSaplingRoot = current_work.GetBlock().hashFinalSaplingRoot;
        blkhdr.hashMerkleRoot = current_work.GetBlock().hashMerkleRoot;
        blkhdr.nNonce = (uint256) nonce;

        // example how to display constructed block
        // if (instance_of_cstratumparams.fstdErrDebugOutput) {
        //     CBlockIndex index {blkhdr};
        //     index.SetHeight(current_work.nHeight);
        //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " blkhdr.hashPrevBlock = " << blkhdr.hashPrevBlock.GetHex() << std::endl;
        //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " blkhdr = " << blockToJSON(blkhdr, &index).write() << std::endl;
        // }

        // block is constructed, now it's time to VerifyEH

        if (instance_of_cstratumparams.fCheckEquihashSolution && !CheckEquihashSolution(&blkhdr, Params()))
                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid equihash solution");

        arith_uint256 bnTarget; bool fNegative, fOverflow;
        bnTarget.SetCompact(blkhdr.nBits, &fNegative, &fOverflow);

        // check range
        // if (fNegative || bnTarget == 0 || fOverflow || bnTarget > UintToArith256(params.powLimit))
        //     return false;

        if (UintToArith256(blkhdr.GetHash()) > bnTarget) {
            res = false;
        } else {
            uint8_t pubkey33[33]; int32_t height = current_work.nHeight;
            res = CheckProofOfWork(blkhdr, pubkey33, height, Params().GetConsensus());
        }
        // if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << "res[1] = " << res << std::endl;

        uint256 hash = blkhdr.GetHash();

        // bits = GetNextWorkRequired(blockindex, nullptr, Params().GetConsensus());

        static uint64_t counter_TotalBlocks, counter_TotalShares, counter_prev;
        if (res)
            counter_TotalBlocks++;
        counter_TotalShares++;

        // https://en.cppreference.com/w/cpp/types/integer - PRId64, PRIu64 (people always forget about various OS and format specifications)

        // native proof-of-work difficulty
        CBlockIndex tmp_index;

        tmp_index.nBits = blkhdr.nBits;
        double hush_target_diff = GetDifficulty(&tmp_index); // diff from nbits (target)
        tmp_index.nBits = UintToArith256(hash).GetCompact();
        double hush_real_diff = GetDifficulty(&tmp_index); // real diff (from hash)
        tmp_index.nBits = arith_uint256(current_work.local_diff).GetCompact();
        double hush_local_diff = GetDifficulty(&tmp_index); // local diff (from local port diff)

        double ccminer_real_diff = ccminer::equi_stratum_target_to_diff(hash.ToString());
        double ccminer_target_diff = ccminer::equi_stratum_target_to_diff(arith_uint256().SetCompact(blkhdr.nBits).ToString());
        double ccminer_local_diff = ccminer::equi_stratum_target_to_diff(current_work.local_diff);

        static std::chrono::high_resolution_clock::time_point start;
        std::chrono::high_resolution_clock::time_point finish = std::chrono::high_resolution_clock::now();
        std::chrono::duration<double, std::milli> elapsed;
        uint64_t shares_accepted_since_last;

        // TODO: we need to check hash > local port diff, and if it's true -> throw an exception -> diff too low (!)
        if (!instance_of_cstratumparams.fAllowLowDiffShares)
            if (UintToArith256(blkhdr.GetHash()) > arith_uint256(current_work.local_diff))
                throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Low diff share (diff %g, local %g)", hush_real_diff, hush_local_diff));

        if (finish > start)
        {
            elapsed = finish - start;
            shares_accepted_since_last = counter_TotalShares - counter_prev;
            start = finish;
            counter_prev = counter_TotalShares;
            // std::cerr << strprintf("%f ms - %" PRIu64 "", elapsed.count(), shares_accepted_since_last) << std::endl;
        }

        bool fDisplayDiffHUSH = true; // otherwise it will display ccminer diff

        std::cerr << DateTimeStrPrecise() <<
                     strprintf("%saccepted: %" PRIu64 "/%" PRIu64 "%s ", ColorTypeNames[cl_WHT], counter_TotalBlocks, counter_TotalShares, ColorTypeNames[cl_N] );
        if (fDisplayDiffHUSH) {
            /* hushd diff display */
            std::cerr << strprintf("%slocal %g%s ", "\x1B[90m", hush_local_diff, ColorTypeNames[cl_N]) <<
                         strprintf("%s(diff %g, target %g) %s ", ColorTypeNames[cl_WHT], hush_real_diff, hush_target_diff, ColorTypeNames[cl_N]);
        } else {   /* ccminer diff display */
            std::cerr << strprintf("%slocal %.3f%s ", "\x1B[90m", ccminer_local_diff, ColorTypeNames[cl_N]) <<
                         strprintf("%s(diff %.3f, target %.3f) %s", ColorTypeNames[cl_WHT], ccminer_real_diff, ccminer_target_diff, ColorTypeNames[cl_N]); // ccminer diff
        }

        std::cerr << "" <<
                     strprintf("%f ms ", elapsed.count()) << // 1 share took elapsed ms
                     strprintf("%s%s%s ", ColorTypeNames[cl_LGR], (res ? "yay!!!": "yes!"), ColorTypeNames[cl_N]) <<
        std::endl;

        // (diff %g, target %g), %
        if (res) {

            LogPrintf("GOT BLOCK!!! by %s: %s\n", client.m_addr.ToString(), hash.ToString());

            CBlock block(current_work.GetBlock());
            // block.vtx[0] = MakeTransactionRef(std::move(cb));
            block.vtx[0] = cb;

            // if (!current_work.m_aux_hash2 && current_work.m_is_witness_enabled) {
            //     block.vtx.back() = MakeTransactionRef(std::move(bf));
            // }
            block.nVersion = version;
            // block.hashMerkleRoot = BlockMerkleRoot(block);
            block.hashMerkleRoot = block.BuildMerkleTree();
            //if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << "hashMerkleRoot = " << block.hashMerkleRoot.GetHex() << std::endl;

            block.nTime = nTime;
            // block.nNonce = nNonce;
            // nNonce <<= 32; nNonce >>= 16; // clear the top and bottom 16 bits (for local use as thread flags and counters)

            block.nNonce = (uint256) nonce;
            block.nSolution = std::vector<unsigned char>(sol.begin() + 3, sol.end());

            // example how to pre-check the equihash solution
            // if(instance_of_cstratumparams.fstdErrDebugOutput) {
            //     CBlockIndex index {blkhdr};
            //     index.SetHeight(-1);
            //     std::cerr << "block = " << blockToJSON(block, &index, true).write(1) << std::endl;
            //     std::cerr << "CheckEquihashSolution = " << CheckEquihashSolution(&block, Params()) << std::endl;
            // }

            // std::shared_ptr<const CBlock> pblock = std::make_shared<const CBlock>(block);
            // res = ProcessNewBlock(Params(), pblock, true, NULL);

            CValidationState state;
            res = ProcessNewBlock(0,0,state, NULL, &block, true /* forceProcessing */ , NULL);

            //if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << "res[2] = " << res << std::endl;

            // we haven't PreciousBlock, so we can't prioritize the block this way for now
            /*
            if (res) {
                // LOCK(cs_main);
                if (!mapBlockIndex.count(hash)) {
                    LogPrintf("Unable to find new block index entry; cannot prioritise block 0x%s\n", hash.ToString());
                } else
                {
                    CBlockIndex* block_index = mapBlockIndex.at(hash);
                    CValidationState state;

                    // PreciousBlock(state, Params(), block_index);
                    // if (!state.IsValid()) {
                    //     LogPrintf("Database error while prioritising new block 0x%s: %d (%s) %s\n", hash.ToString(), state.GetRejectCode(), state.GetRejectReason(), state.GetDebugMessage());
                    // }
                }
            }
            */
        } else {
            LogPrintf("NEW SHARE!!! by %s: %s\n", client.m_addr.ToString(), hash.ToString());
        }
    }

    if (res) {
        client.m_send_work = true;
    }

    return res;
}

void BoundParams(const std::string& method, const UniValue& params, size_t min, size_t max)
{
    if (params.size() < min) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("%s expects at least %d parameters; received %d", method, min, params.size()));
    }

    if (params.size() > max) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("%s receives no more than %d parameters; got %d", method, max, params.size()));
    }
}

UniValue stratum_mining_subscribe(StratumClient& client, const UniValue& params)
{
    const std::string method("mining.subscribe");
    BoundParams(method, params, 0, 4);

    if (params.size() >= 1) {
        client.m_client = params[0].get_str();
        LogPrint("stratum", "Received subscription from client %s\n", client.m_client);
    }

    // According to 'Stratum protocol changes for ZCash' - https://github.com/slushpool/poclbm-zcash/wiki/Stratum-protocol-changes-for-ZCash
    // mining.subscribe params looks like following:

    // {"id": 1, "method": "mining.subscribe", "params": ["CONNECT_HOST", CONNECT_PORT, "MINER_USER_AGENT", "SESSION_ID"]}
    // So, params[params.size()-1] should be SESSION_ID, but currently we don't support it.

    // Also we should answer with these:
    // {"id": 1, "result": ["SESSION_ID", "NONCE_1"], "error": null}
    // {"id":1,"result":[null,"81000001"],"error":null}

    // NONCE_1 is first part of the block header nonce (in hex).

    // By protocol, Zcash's nonce is 32 bytes long. The miner will pick NONCE_2 such that len(NONCE_2) = 32 - len(NONCE_1).
    // Please note that Stratum use hex encoding, so you have to convert NONCE_1 from hex to binary before.

    // ["CONNECT_HOST", CONNECT_PORT, "MINER_USER_AGENT", "SESSION_ID"]
    // ["NiceHash/1.0.0", null, "stratum.hush.is", 28030] // ua, session_id, host, port?
    // ["ccminer/2.3.1"]

    UniValue ret(UniValue::VARR);

    // ExtraNonce1 -> client.m_supports_extranonce is false, so the job_id isn't used
    std::vector<unsigned char> vExtraNonce1 = client.ExtraNonce1(uint256());

    // std::string sExtraNonce1 = HexStr(vExtraNonce1.begin(), vExtraNonce1.begin() + (vExtraNonce1.size() > 3 ? 4 : vExtraNonce1.size()));
    std::string sExtraNonce1 = HexStr(vExtraNonce1);

    /**
     * Potentially we can use something like strprintf("%08x", GetRand(std::numeric_limits<uint64_t>::max())
     * here to generate sExtraNonce1, but don't forget that client.ExtraNonce1 method return 8 bytes
     * job_nonce:8 = sha256(client.m_secret:32 + client.job_id:32) , so, somewhere in future we can re-calculate
     * sExtraNonce1 for a given client based on m_secret.
     */

    // if (instance_of_cstratumparams.fstdErrDebugOutput && vExtraNonce1.size() > 3) {
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " " << strprintf("client.m_supports_extranonce = %d, [%d, %d, %d, %d], %s", client.m_supports_extranonce, vExtraNonce1[0], vExtraNonce1[1], vExtraNonce1[2], vExtraNonce1[3], sExtraNonce1) << std::endl;
    //     // recalc from client.m_secret example
    //     uint256 sha256;
    //     CSHA256().Write(client.m_secret.begin(), 32).Finalize(sha256.begin());
    //     std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << " " << HexStr(std::vector<unsigned char>(sha256.begin(), sha256.begin() + 4)) << std::endl;
    // }

    ret.push_back(NullUniValue);
    ret.push_back(sExtraNonce1);

    // On mining.subscribe we don't need to send anything else, we will send
    // mining.set_target and mining.notify bit later, inside GetWorkUnit.
    // Scheme is the following:
    // 1. stratum_read_cb(bufferevent * bev, void * ctx)
    // 2. if (client.m_send_work) -> GetWorkUnit
    // 3. CustomizeWork (throw if error and exit from GetWorkUnit)
    // 4. set_target
    // 5. ...
    // Last. GetWorkUnit returns string data (!) to send to client ( ... + mining.set_target + mining.notify + ... )

    return ret;
}

UniValue stratum_mining_authorize(StratumClient& client, const UniValue& params)
{
    const std::string method("mining.authorize");
    BoundParams(method, params, 1, 2);

    std::string username = params[0].get_str();
    boost::trim(username);

    // params[1] is the client-provided password.  We do not perform
    // user authorization, so we ignore this value.

    double mindiff = 0.0;
    size_t pos = username.find('+');
    if (pos != std::string::npos) {
        // Extract the suffix and trim it
        std::string suffix(username, pos+1);
        boost::trim_left(suffix);
        // Extract the minimum difficulty request
        mindiff = boost::lexical_cast<double>(suffix);
        // Remove the '+' and everything after
        username.resize(pos);
        boost::trim_right(username);
    }

    CBitcoinAddress addr(get_stripped_username(username));

    // If given the special address "x", mine to the default address given by -stratumaddress
    // This means a miner can run a private pool without TLS and not
    // worry about MITM attacks that change addresses, and leaks less metadata.
    // It also means many miners can be used and updating their mining address does not
    // require any changes on each miner, just restart hushd with a new -stratumaddress
    if(addr.ToString() == "x") {
        addr = CBitcoinAddress(GetArg("-stratumaddress", ""));
        const std::string msg = strprintf("%s: Authorized client with default stratum address=%s", __func__, addr.ToString());
        LogPrint("stratum", "%s\n", msg);
    }

    if (!addr.IsValid()) {
        const std::string msg = strprintf("%s: Invalid Hush address=%s", __func__, addr.ToString());
        LogPrint("stratum", "%s\n", msg);
        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid Hush address: %s", username));
    }

    client.m_addr       = addr;
    client.m_mindiff    = mindiff;
    client.m_authorized = true;
    client.m_send_work  = true;

    LogPrintf("Authorized stratum miner %s from %s, mindiff=%f\n", addr.ToString(), client.GetPeer().ToString(), mindiff);

    return true;
}

UniValue stratum_mining_configure(StratumClient& client, const UniValue& params)
{
    const std::string method("mining.configure");
    BoundParams(method, params, 2, 2);

    UniValue res(UniValue::VOBJ);

    UniValue extensions = params[0].get_array();
    UniValue config = params[1].get_obj();
    for (int i = 0; i < extensions.size(); ++i) {
        std::string name = extensions[i].get_str();

        if ("version-rolling" == name) {
            uint32_t mask = ParseHexInt4(find_value(config, "version-rolling.mask"), "version-rolling.mask");
            size_t min_bit_count = find_value(config, "version-rolling.min-bit-count").get_int();
            client.m_version_rolling_mask = mask & 0x1fffe000;
            res.push_back(Pair("version-rolling", true));
            res.push_back(Pair("version-rolling.mask", HexInt4(client.m_version_rolling_mask)));
            LogPrint("stratum", "Received version rolling request from %s\n", client.GetPeer().ToString());
        }

        else {
            LogPrint("stratum", "Unrecognized stratum extension '%s' sent by %s\n", name, client.GetPeer().ToString());
        }
    }

    return res;
}

UniValue stratum_mining_submit(StratumClient& client, const UniValue& params)
{
    // {"id": 4, "method": "mining.submit", "params": ["WORKER_NAME", "JOB_ID", "TIME", "NONCE_2", "EQUIHASH_SOLUTION"]}\n

    // NONCE_1 is first part of the block header nonce (in hex).
    // By protocol, Zcash's nonce is 32 bytes long. The miner will pick NONCE_2 such that len(NONCE_2) = 32 - len(NONCE_1). Please note that Stratum use hex encoding, so you have to convert NONCE_1 from hex to binary before.
    // NONCE_2 is the second part of the block header nonce.
    /**
     *
     * {"method":"mining.submit","params":[
        [0] WORKER_NAME "RDeckerSubnU8QVgrhj27apzUvbVK3pnTk",
        [1] JOB_ID "1",
        [2] TIME "0eaec560",
        [3] NONCE_2 "0000000000000000d890000001000000000000000000000000000000",
        [4] EQUIHASH_SOLUTION(1347) "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"
        ],
        "id":10}
     */

    const std::string method("mining.submit");
    BoundParams(method, params, 5,5);
    // First parameter is the client username, which is ignored.

    /* EWBF 31 bytes job_id fix */
    bool fEWBFJobIDFixNeeded = false;
    uint256 ret;
    if (params[1].isStr()) {
        //std::cerr << "\"" << params[1].get_str() << "\"" << std::endl;
        const std::string job_id_str = params[1].get_str();
        const std::string hexDigits = "0123456789abcdef";
        // std::cerr << strprintf("\"%s\" (%d)", job_id_str, job_id_str.length()) << std::endl;
        if (job_id_str.length() == 63) {
            fEWBFJobIDFixNeeded = true;
            for(const auto& hexDigit : hexDigits) {
                ret = uint256(ParseHex(job_id_str + hexDigit));
                if (work_templates.count(ret)) break;
            }
        }
    }

    uint256 job_id;
    if (!fEWBFJobIDFixNeeded)
        job_id = ParseUInt256(params[1], "job_id");
    else
        job_id = ret;

    // uint256 job_id = ParseUInt256(params[1], "job_id");
    if (!work_templates.count(job_id)) {
        LogPrint("stratum", "Received completed share for unknown job_id : %s\n", HexStr(job_id.begin(), job_id.end()));
        return false;
    }

    StratumWork &current_work = work_templates[job_id];

    uint32_t nTime = bswap_32(ParseHexInt4(params[2], "nTime"));

    std::vector<unsigned char> sol = ParseHexV(params[4], "solution");
    if (sol.size() != 1347) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("solution is wrong length (received %d bytes; expected %d bytes", sol.size(), 1347));
    }

    std::vector<unsigned char> extranonce1 = client.ExtraNonce1(job_id);
    std::vector<unsigned char> extranonce2 = ParseHexV(params[3], "extranonce2");
    boost::optional<uint32_t> nVersion = 4; // block version always 4

    SubmitBlock(client, job_id, current_work, extranonce1, extranonce2, nVersion, nTime, sol);

    return true;
}

UniValue stratum_mining_extranonce_subscribe(StratumClient& client, const UniValue& params)
{
    const std::string method("mining.extranonce.subscribe");
    BoundParams(method, params, 0, 0);

    /*client.m_supports_extranonce = true;

    return true;*/
    client.m_supports_extranonce = false;

    return true;
}

UniValue stratum_mining_multi_version(StratumClient& client, const UniValue& params)
{
    const std::string method("mining.multi_version");
    BoundParams(method, params, 0, 1);

    /*
    Received stratum request from Miner: {"id": 135828, "method": "mining.multi_version", "params": [1]}
    Sending stratum response to Miner : {"result":null,"error":{"code":-32601,"message":"Method 'mining.multi_version' not found"},"id":135828}
    */

    return false;
}



/** Callback to write from a stratum connection. */
static void stratum_write_cb(bufferevent *bev, void *ctx)
{
    /* template */
}

/** Callback to read from a stratum connection. */
static void stratum_read_cb(bufferevent *bev, void *ctx)
{
    evconnlistener *listener = (evconnlistener*)ctx;
    LOCK(cs_stratum);
    // Lookup the client record for this connection
    if (!subscriptions.count(bev)) {
        LogPrint("stratum", "Received read notification for unknown stratum connection 0x%x\n", (size_t)bev);
        return;
    }
    StratumClient& client = subscriptions[bev];
    // Get links to the input and output buffers
    evbuffer *input = bufferevent_get_input(bev);
    assert(input);
    evbuffer *output = bufferevent_get_output(bev);
    assert(output);

    // Process each line of input that we have received
    char *cstr = 0;
    size_t len = 0;
    while ((cstr = evbuffer_readln(input, &len, EVBUFFER_EOL_CRLF))) {
        std::string line(cstr, len);
        free(cstr);
        LogPrint("stratum", "Received stratum request from %s : %s\n", client.GetPeer().ToString(), line);

        JSONRequest jreq;

        std::string reply;
        try {
            // Parse request
            UniValue valRequest;
            if (!valRequest.read(line)) {
                // Not JSON; is this even a stratum miner?
                throw JSONRPCError(RPC_PARSE_ERROR, strprintf("Invalid JSON, Parse error on: %s",line) );
            }
            if (!valRequest.isObject()) {
                // Not a JSON object; don't know what to do.
                throw JSONRPCError(RPC_PARSE_ERROR, "Not a JSON object");
            }
            if (valRequest.exists("result")) {
                // JSON-RPC reply.  Ignore.
                LogPrint("stratum", "Ignoring JSON-RPC response\n");
                continue;
            }
            jreq.parse(valRequest);

            // Dispatch to method handler
            UniValue result = NullUniValue;
            if (stratum_method_dispatch.count(jreq.strMethod)) {
                result = stratum_method_dispatch[jreq.strMethod](client, jreq.params);
            } else {
                throw JSONRPCError(RPC_METHOD_NOT_FOUND, strprintf("Method '%s' not found", jreq.strMethod));
            }

            // Compose reply
            reply = JSONRPCReply(result, NullUniValue, jreq.id);
        } catch (const UniValue& objError) {
            reply = JSONRPCReply(NullUniValue, objError, jreq.id);
        } catch (const std::exception& e) {
            reply = JSONRPCReply(NullUniValue, JSONRPCError(RPC_INTERNAL_ERROR, e.what()), jreq.id);
        }

        LogPrint("stratum", "Sending stratum response to %s : %s", client.GetPeer().ToString(), reply);
        assert(output);
        if (evbuffer_add(output, reply.data(), reply.size())) {
            LogPrint("stratum", "Sending stratum response failed. (Reason: %d, '%s')\n", errno, evutil_socket_error_to_string(errno));
        }
    }

    // If required, send new work to the client.
    if (client.m_send_work) {
        std::string data;
        try {
            data = GetWorkUnit(client);
        } catch (const UniValue& objError) {
            data = JSONRPCReply(NullUniValue, objError, NullUniValue);
        } catch (const std::exception& e) {
            data = JSONRPCReply(NullUniValue, JSONRPCError(RPC_INTERNAL_ERROR, e.what()), NullUniValue);
        }

        LogPrint("stratum", "Sending requested stratum work unit to %s : %s", client.GetPeer().ToString(), data);
        assert(output);
        if (evbuffer_add(output, data.data(), data.size())) {
            LogPrint("stratum", "Sending stratum work unit failed. (Reason: %d, '%s')\n", errno, evutil_socket_error_to_string(errno));
        }

        client.m_send_work = false;
    }
}

/** Callback to handle unrecoverable errors in a stratum link. */
static void stratum_event_cb(bufferevent *bev, short what, void *ctx)
{
    evconnlistener *listener = (evconnlistener*)ctx;
    LOCK(cs_stratum);
    // Fetch the return address for this connection, for the debug log.
    std::string from("UNKNOWN");
    if (!subscriptions.count(bev)) {
        LogPrint("stratum", "Received event notification for unknown stratum connection 0x%x\n", (size_t)bev);
        return;
    } else {
        from = subscriptions[bev].GetPeer().ToString();
    }
    // Report the reason why we are closing the connection.
    if (what & BEV_EVENT_ERROR) {
        LogPrint("stratum", "Error detected on stratum connection from %s\n", from);
    }
    if (what & BEV_EVENT_EOF) {
        LogPrint("stratum", "Remote disconnect received on stratum connection from %s\n", from);
    }
    // Remove the connection from our records, and tell libevent to
    // disconnect and free its resources.
    if (what & (BEV_EVENT_EOF | BEV_EVENT_ERROR)) {
        LogPrint("stratum", "Closing stratum connection from %s\n", from);
        subscriptions.erase(bev);
        if (bev) {
            bufferevent_free(bev);
            bev = NULL;
        }
    }
}

/** Callback to accept a stratum connection. */
static void stratum_accept_conn_cb(evconnlistener *listener, evutil_socket_t fd, sockaddr *address, int socklen, void *ctx)
{
    // Parse the return address
    CService from;
    from.SetSockAddr(address);
    // Early address-based allow check

    if (!ClientAllowed(stratum_allow_subnets, from))
    {
        // evconnlistener_free(listener);

        /*
            Here we shouldn't free listener, bcz if somebody will connect on stratum port from
            disallowed network -> future connections will be anavailable.
        */
        LogPrint("stratum", "Rejected connection from disallowed subnet: %s\n", from.ToString());
        return;
    }

    {
        LOCK(cs_stratum);
        // Should be the same as EventBase(), but let's get it the official way.
        event_base *base = evconnlistener_get_base(listener);
        // Create a buffer for sending/receiving from this connection.
        bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
        // Disable Nagle's algorithm, so that TCP packets are sent
        // immediately, even if it results in a small packet.
        int one = 1;
        setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char*)&one, sizeof(one));
        // Setup the read and event callbacks to handle receiving requests
        // from the miner and error handling.  A write callback isn't
        // needed because we're not sending enough data to fill buffers.
        bufferevent_setcb(bev, stratum_read_cb, NULL, stratum_event_cb, (void*)listener);
        // Enable bidirectional communication on the connection.
        bufferevent_enable(bev, EV_READ|EV_WRITE);
        // Record the connection state
        subscriptions[bev] = StratumClient(listener, fd, bev, from);
        // Log the connection.
        LogPrint("stratum", "Accepted stratum connection from %s\n", from.ToString());
    }
}

/** Setup the stratum connection listening services */
static bool StratumBindAddresses(event_base* base)
{
    int stratumPort = BaseParams().StratumPort();
    int defaultPort = GetArg("-stratumport", stratumPort);
    std::vector<std::pair<std::string, uint16_t> > endpoints;

    // Determine what addresses to bind to
    if (!mapArgs.count("-stratumallowip")) { // Default to loopback if not allowing external IPs
        endpoints.push_back(std::make_pair("::1", defaultPort));
        endpoints.push_back(std::make_pair("127.0.0.1", defaultPort));
        if (mapArgs.count("-stratumbind")) {
            LogPrintf("WARNING: option -stratumbind was ignored because -stratumallowip was not specified, refusing to allow everyone to connect\n");
        }
    } else if (mapArgs.count("-stratumbind")) { // Specific bind address
        const std::vector<std::string>& vbind = mapMultiArgs["-stratumbind"];
        for (std::vector<std::string>::const_iterator i = vbind.begin(); i != vbind.end(); ++i) {
            int port = defaultPort;
            std::string host;
            SplitHostPort(*i, port, host);
            endpoints.push_back(std::make_pair(host, port));
        }
    } else { // No specific bind address specified, bind to any
        endpoints.push_back(std::make_pair("::", defaultPort));
        endpoints.push_back(std::make_pair("0.0.0.0", defaultPort));
    }

    // Bind each addresses
    for (const auto& endpoint : endpoints) {
        LogPrint("stratum", "Binding stratum on address %s port %i\n", endpoint.first, endpoint.second);
        // Use CService to translate string -> sockaddr
        CNetAddr netaddr;
        std::vector<CNetAddr> vIP;

        LookupHost(endpoint.first.c_str(), vIP, 1, true);
        assert(vIP.size() >= 1);

        netaddr = vIP[0];

        CService socket(netaddr, endpoint.second);
        union {
            sockaddr     ipv4;
            sockaddr_in6 ipv6;
        } addr;
        socklen_t len = sizeof(addr);
        socket.GetSockAddr((sockaddr*)&addr, &len);
        // Setup an event listener for the endpoint
        evconnlistener *listener = evconnlistener_new_bind(base, stratum_accept_conn_cb, NULL, LEV_OPT_CLOSE_ON_FREE|LEV_OPT_REUSEABLE, -1, (sockaddr*)&addr, len);
        // Only record successful binds
        if (listener) {
            bound_listeners[listener] = socket;
        } else {
            LogPrintf("Binding stratum on address %s port %i failed. (Reason: %d, '%s')\n", endpoint.first, endpoint.second, errno, evutil_socket_error_to_string(errno));
        }
    }

    return !bound_listeners.empty();
}

/** Watches for new blocks and send updated work to miners. */
static bool g_shutdown = false;

void BlockWatcher()
{
    RenameThread("hush-stratum-blkwatcher");
    boost::unique_lock<boost::mutex> lock(csBestBlock);
    boost::system_time checktxtime;
    boost::system_time starttime = boost::get_system_time();

    unsigned int txns_updated_last = 0;
    boost::posix_time::time_duration time_passed = boost::posix_time::seconds(0);
    bool fRebroadcastAnyway = false;

    if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << " time = " << boost::get_system_time() << " checktxtime = " << checktxtime << std::endl;
    while (true) { // (A)
        /* This will execute before waiting of cvBlockChange */

        if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << " time = " << boost::get_system_time() << " checktxtime = " << checktxtime << std::endl;
        checktxtime = boost::get_system_time() + boost::posix_time::seconds(txMemPoolCheckTimeout);
        // - time_passed
        if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << " time = " << boost::get_system_time() << " checktxtime = " << checktxtime << std::endl;

        if (!cvBlockChange.timed_wait(lock, checktxtime)) {
            // Timeout: Check to see if mempool was updated.

            /* This will execute after txMemPoolCheckTimeout seconds */
            unsigned int txns_updated_next = mempool.GetTransactionsUpdated();

            if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << ColorTypeNames[cl_WHT] << " seconds_passed = " << (boost::get_system_time() - starttime) << ColorTypeNames[cl_N] << " txns_updated_last = " << txns_updated_last << " txns_updated_next = " << txns_updated_next << std::endl;
            time_passed = boost::posix_time::time_duration(boost::get_system_time() - starttime);

            if ((boost::get_system_time() - starttime) < boost::posix_time::seconds(jobRebroadcastTimeout)) {
                if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << "seconds_passed < jobRebroadcastTimeout" << std::endl;
                fRebroadcastAnyway = false;
                if (txns_updated_last == txns_updated_next) continue; // (A)
            } else {
                if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << ColorTypeNames[cl_GRN] << "Force update work!"<< ColorTypeNames[cl_N] << " seconds_passed >= jobRebroadcastTimeout" << std::endl;
                // in case of rebroadcast we should "emulate" that everything is changed and clients must go for new work
                mempool.AddTransactionsUpdated(1);
                for (auto& subscription : subscriptions) {
                    subscription.second.m_last_tip = (subscription.second.m_last_tip ? nullptr : chainActive.Tip());
                }
                fRebroadcastAnyway = true;
                starttime += boost::posix_time::seconds(jobRebroadcastTimeout);
            }

            if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << std::endl;
            txns_updated_last = txns_updated_next;
        }

        /* This will excute after wait cvBlockChange will completed, or if 'timeout branch' will allow
           execution goes here (mean, if it will not use condition with `continue`) */

        if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << " time = " << boost::get_system_time() << " checktxtime = " << checktxtime << std::endl;

        if (g_shutdown) {
            break;
        }

        // Either new block, or updated transactions.  Either way,
        // send updated work to miners.
        {
            LOCK(cs_stratum);
            for (auto& subscription : subscriptions) {

            bufferevent* bev = subscription.first;

            if (!bev)
                continue;
            evbuffer *output = bufferevent_get_output(bev);
            if (!output)
                continue;

            StratumClient& client = subscription.second;
            // Ignore clients that aren't authorized yet.
            if (!client.m_authorized && client.m_aux_addr.empty()) {
                continue;
            }
            // Ignore clients that are already working on the new block.
            // Typically this is just the miner that found the block, who was
            // immediately sent a work update.  This check avoids sending that
            // work notification again, moments later.  Due to race conditions
            // there could be more than one miner that have already received an
            // update, however.
            if (!fRebroadcastAnyway && client.m_last_tip == chainActive.Tip()) {
                continue;
            }

            if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << " time = " << boost::get_system_time() << " checktxtime = " << checktxtime << std::endl;

            // Get new work
            std::string data;
            try {
                data = GetWorkUnit(client);
            } catch (const UniValue& objError) {
                data = JSONRPCReply(NullUniValue, objError, NullUniValue);
            } catch (const std::exception& e) {
                // Some sort of error.  Ignore.
                std::string msg = strprintf("Error generating updated work for stratum client: %s", e.what());
                LogPrint("stratum", "%s\n", msg);
                data = JSONRPCReply(NullUniValue, JSONRPCError(RPC_INTERNAL_ERROR, msg), NullUniValue);
            }
            // Send the new work to the client

            assert(output);
            if (evbuffer_add(output, data.data(), data.size())) {
                LogPrint("stratum", "Sending stratum work unit failed. (Reason: %d, '%s')\n", errno, evutil_socket_error_to_string(errno));
            }
        }
        }

        if (instance_of_cstratumparams.fstdErrDebugOutput) std::cerr << DateTimeStrPrecise() << __func__ << ": " << __FILE__ << "," << __LINE__ << " time = " << boost::get_system_time() << " checktxtime = " << checktxtime << std::endl;
    }
}

void SendKeepAlivePackets()
{
    RenameThread("hush-stratum-keepalive");
    while (true) {
        // Run the notifier on an integer second in the steady clock.
        auto now = std::chrono::steady_clock::now().time_since_epoch();
        auto nextFire = std::chrono::duration_cast<std::chrono::seconds>(
            now + std::chrono::seconds(10));
        std::this_thread::sleep_until(
        std::chrono::time_point<std::chrono::steady_clock>(nextFire));

        boost::this_thread::interruption_point();

        // Either new block, or updated transactions.  Either way,
        // send updated work to miners.
        for (auto& subscription : subscriptions) {
            bufferevent* bev = subscription.first;

            if (!bev)
                continue;
            evbuffer *output = bufferevent_get_output(bev);
            if (!output)
                continue;
            evbuffer *input = bufferevent_get_input(bev);
            if (!input)
                continue;

            StratumClient& client = subscription.second;

            if (instance_of_cstratumparams.fstdErrDebugOutput) {
                std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << std::endl <<
                "client.m_authorized = " << client.m_authorized << std::endl <<
                "client.m_aux_addr.size() = " << client.m_aux_addr.size() << std::endl <<
                "client.m_last_tip = " << strprintf("%p", client.m_last_tip) << std::endl <<
                (client.m_last_tip ? strprintf("client.m_last_tip->GetHeight() = %d", client.m_last_tip->GetHeight()) : "") << std::endl <<
                "chainActive.Tip()->GetHeight() = " << chainActive.Tip()->GetHeight() << std::endl <<
                "client.m_supports_extranonce = " << client.m_supports_extranonce << std::endl <<
                "client.m_send_work = " << client.m_send_work << std::endl <<
                std::endl;
            }

            // Ignore clients that aren't authorized yet.
            if (!client.m_authorized && client.m_aux_addr.empty()) {
                continue;
            }

            std::string data = "\r\n";
            // to see the socket / connection is alive, we will see bunch of
            // JSON decode failed(1): '[' or '{' expected near end of file
            // on client if will send "\r\n" every second

            assert(output);
            if (evbuffer_add(output, data.data(), data.size())) {
                LogPrint("stratum", "Sending stratum keepalive unit failed. (Reason: %d, '%s')\n", errno, evutil_socket_error_to_string(errno));
            }

            if ( (client.m_last_tip && client.m_last_tip->GetHeight() == chainActive.Tip()->GetHeight()) || (!client.m_last_tip) )
            {
                LOCK(cs_stratum);
                std::cerr << DateTimeStrPrecise() << "\033[31m" << client.m_from.ToString() << "\033[0m seems stucked (ccminer issue), need to emulate new block incoming to unstuck!" << std::endl;
                mempool.AddTransactionsUpdated(1);
                client.m_last_tip = (client.m_last_tip ? nullptr : chainActive.Tip());
                client.m_nextid++;
                cvBlockChange.notify_all(); // change the state of all threads waiting on *this to ready
                // cvBlockChange.notify_one(); // if there is a thread waiting on *this, change that thread state to ready
            }
        }

    }

}

/** Configure the Hush stratum server */
bool InitStratumServer()
{
    LOCK(cs_stratum);

    int stratumPort = BaseParams().StratumPort();
    int defaultPort = GetArg("-stratumport", stratumPort);
    fprintf(stderr,"%s: Starting built-in stratum server on port %d\n",__func__, defaultPort );


    if (!InitStratumAllowList(stratum_allow_subnets)) {
        LogPrint("stratum", "Unable to bind stratum server to an endpoint.\n");
        return false;
    }

    std::string strAllowed;
    for(const CSubNet& subnet : stratum_allow_subnets)
        strAllowed += subnet.ToString() + " ";
    LogPrint("stratum", "Allowing Stratum connections from: %s\n", strAllowed);

    event_base* base = EventBase();
    if (!base) {
        LogPrint("stratum", "No event_base object, cannot setup stratum server.\n");
        return false;
    }

    if (!StratumBindAddresses(base)) {
        LogPrintf("Unable to bind any endpoint for stratum server\n");
    } else {
        LogPrint("stratum", "Initialized stratum server\n");
    }

    stratum_method_dispatch["mining.subscribe"]            = stratum_mining_subscribe;
    stratum_method_dispatch["mining.authorize"]            = stratum_mining_authorize;
    stratum_method_dispatch["mining.configure"]            = stratum_mining_configure;
    stratum_method_dispatch["mining.submit"]               = stratum_mining_submit;
    stratum_method_dispatch["mining.extranonce.subscribe"] = stratum_mining_extranonce_subscribe;
    stratum_method_dispatch["mining.multi_version"]        = stratum_mining_multi_version;


    // Start thread to wait for block notifications and send updated
    // work to miners.
    block_watcher_thread = boost::thread(BlockWatcher);
    // block_watcher_thread = boost::thread(SendKeepAlivePackets);

    return true;
}

/** Interrupt the stratum server connections */
void InterruptStratumServer()
{
    LOCK(cs_stratum);
    // Stop listening for connections on stratum sockets
    for (const auto& binding : bound_listeners) {
        LogPrint("stratum", "Interrupting stratum service on %s\n", binding.second.ToString());
        evconnlistener_disable(binding.first);
    }
    // Tell the block watching thread to stop
    g_shutdown = true;
}

/** Cleanup stratum server network connections and free resources. */
void StopStratumServer()
{
    LOCK(cs_stratum);
    /* Tear-down active connections. */
    for (const auto& subscription : subscriptions) {
        LogPrint("stratum", "Closing stratum server connection to %s due to process termination\n", subscription.second.GetPeer().ToString());
        bufferevent_free(subscription.first);
    }
    subscriptions.clear();
    /* Un-bind our listeners from their network interfaces. */
    for (const auto& binding : bound_listeners) {
        LogPrint("stratum", "Removing stratum server binding on %s\n", binding.second.ToString());
        evconnlistener_free(binding.first);
    }
    bound_listeners.clear();
    /* Free any allocated block templates. */
    work_templates.clear();
}

/* RPC */
UniValue rpc_stratum_updatework(const UniValue& params, bool fHelp, const CPubKey& mypk)
{
    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "stratum_updatework\n"
            "Tries to immediatelly update work on all connected miners.\n"
            "\nExamples:\n"
            + HelpExampleCli("stratum_updatework", "")
            + HelpExampleRpc("stratum_updatework", "")
        );

    UniValue obj(UniValue::VOBJ);
    UniValue json_clients(UniValue::VARR);
    uint64_t skipped = 0;

    // send updated work to miners
    // if (cs_stratum.try_lock())
    {
        LOCK(cs_stratum);
        for (auto& subscription : subscriptions) {

            bufferevent* bev = subscription.first;

            if (!bev)
                continue;
            evbuffer *output = bufferevent_get_output(bev);
            if (!output)
                continue;
            evbuffer *input = bufferevent_get_input(bev);
            if (!input)
                continue;

            StratumClient& client = subscription.second;

            if (instance_of_cstratumparams.fstdErrDebugOutput) {
                std::cerr << __func__ << ": " << __FILE__ << "," << __LINE__ << std::endl <<
                "client.m_authorized = " << client.m_authorized << std::endl <<
                "client.m_aux_addr.size() = " << client.m_aux_addr.size() << std::endl <<
                "client.m_last_tip = " << strprintf("%p", client.m_last_tip) << std::endl <<
                (client.m_last_tip ? strprintf("client.m_last_tip->GetHeight() = %d", client.m_last_tip->GetHeight()) : "") << std::endl <<
                "chainActive.Tip()->GetHeight() = " << chainActive.Tip()->GetHeight() << std::endl <<
                "client.m_supports_extranonce = " << client.m_supports_extranonce << std::endl <<
                "client.m_send_work = " << client.m_send_work << std::endl <<
                std::endl;
            }

            // Ignore clients that aren't authorized yet.
            if (!client.m_authorized && client.m_aux_addr.empty()) {
                fprintf(stderr,"%s: Ignoring unauthorized client\n", __func__);
                continue;
            }

            if ( (client.m_last_tip && client.m_last_tip->GetHeight() == chainActive.Tip()->GetHeight()) || (!client.m_last_tip) )
            {
                mempool.AddTransactionsUpdated(1);
                client.m_last_tip = (client.m_last_tip ? nullptr : chainActive.Tip());
                cvBlockChange.notify_all();
            }

            std::string data = "";

            try {
                data = GetWorkUnit(client);

                UniValue json_client(UniValue::VOBJ);
                json_client.push_back(Pair("addr", client.m_addr.ToString()));
                json_client.push_back(Pair("service", client.m_from.ToString()));

                json_clients.push_back(json_client);

            } catch (const UniValue& objError) {
                data = JSONRPCReply(NullUniValue, objError, NullUniValue);
                skipped++;
            } catch (const std::exception& e) {
                // Some sort of error.  Ignore.
                std::string msg = strprintf("Error generating updated work for stratum client: %s", e.what());
                LogPrint("stratum", "%s\n", msg);
                data = JSONRPCReply(NullUniValue, JSONRPCError(RPC_INTERNAL_ERROR, msg), NullUniValue);
                skipped++;
            }

            assert(output);
            if (evbuffer_add(output, data.data(), data.size())) {
                LogPrint("stratum", "Sending stratum work unit failed. (Reason: %d, '%s')\n", errno, evutil_socket_error_to_string(errno));
            }
        }
    }
    // else {
    //     throw JSONRPCError(RPC_INTERNAL_ERROR, "Something went wrong, plz try again!");
    // }

	uint64_t clientsSize = json_clients.size();
	uint64_t subscriptionsSize = subscriptions.size();

    obj.push_back(Pair("clients", json_clients));
    obj.push_back(Pair("updated", clientsSize));
    obj.push_back(Pair("skipped", skipped));
    obj.push_back(Pair("total", subscriptionsSize));

    return obj;
}

UniValue rpc_stratum_getdifficulty (const UniValue& params, bool fHelp, const CPubKey& mypk) {

    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "stratum_getdifficulty\n"
            "Show the current local diff of a stratum port.\n"
            "\nExamples:\n"
            + HelpExampleCli("stratum_getdifficulty", "")
            + HelpExampleRpc("stratum_getdifficulty", "")
        );

    UniValue obj(UniValue::VOBJ);

    arith_uint256 aHashTarget = instance_of_cstratumparams.getTarget();
    std::string strTarget = aHashTarget.GetHex();

    CBlockIndex tmp_index;
    tmp_index.nBits = arith_uint256(strTarget).GetCompact();
    double hush_diff = GetDifficulty(&tmp_index);
    double ccminer_diff = ccminer::equi_stratum_target_to_diff(strTarget);

    obj.push_back(Pair("target", strTarget));
    obj.push_back(Pair("target_compact", strprintf("%08x",tmp_index.nBits)));
    obj.push_back(Pair("hush_diff_str", strprintf("%g",hush_diff)));
    obj.push_back(Pair("ccminer_diff_str", strprintf("%g", ccminer_diff)));
    obj.push_back(Pair("hush_diff", hush_diff));
    obj.push_back(Pair("ccminer_diff", ccminer_diff));

    return obj;
};

UniValue rpc_stratum_setdifficulty (const UniValue& params, bool fHelp, const CPubKey& mypk) {

    /*
        https://bitcoin.stackexchange.com/questions/30467/what-are-the-equations-to-convert-between-bits-and-difficulty

        There are 3 representations of the same thing (with varying degrees of precision) in Bitcoin:

            - bits - unsigned int 32-bit
            - target - unsigned int 256-bit
            - difficulty - double-precision float (64-bit)

        and 6 methods are necessary to convert between any two of these:

            - bits -> target (SetCompact() in bitcoin/src/arith_uint256.cpp)
            - bits -> difficulty (GetDifficulty() in bitcoin/src/rpc/blockchain.cpp)
            - target -> bits (GetCompact() in bitcoin/src/arith_uint256.cpp)
            - target -> difficulty (same as target -> bits -> difficulty)
            - difficulty -> bits (not done in bitcoin/src) -> we will use hush_diff_to_target_equi for that
            - difficulty -> target (same as difficulty -> bits -> target)
    */
    if (fHelp || params.size() != 1)
        throw std::runtime_error(
            "stratum_setdifficulty\n"
            "Set the diff on a stratum port.\n"
            "\nExamples:\n"
            + HelpExampleCli("stratum_setdifficulty", "")
            + HelpExampleRpc("stratum_setdifficulty", "")
        );

    // diff can be accepted in two ways: as a hex target or as a hush_diff, both variants assume
    // passing a string with 32 bytes hex target or string (!) with a double value, or double
    // value as a double

    double hush_diff; // calculated value: diff_str -> hush_diff
    std::string diff_str = instance_of_cstratumparams.getTarget().ToString();

    if (params[0].getType() == UniValue::VSTR) {
        std::string param_str = params[0].get_str();
        if (IsHex(param_str) && param_str.size() == 64) {
            // hex target passed
            diff_str = param_str;

        } else {
            if (ParseDouble(param_str, &hush_diff)) {
                // hush diff as a str passed
                // difficulty = difficulty_1_target / current_target
                arith_uint256 target;
                ccminer::hush_diff_to_target_equi((uint32_t *)&target, hush_diff);
                diff_str = target.ToString();

            } else
                throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid difficulty (not hex target, not hush_diff)");
        }
    } else if (params[0].getType() == UniValue::VNUM) {
        // hush diff as a num passed
        hush_diff = params[0].get_real();

        // difficulty = difficulty_1_target / current_target
        arith_uint256 target;
        ccminer::hush_diff_to_target_equi((uint32_t *)&target, hush_diff);
        diff_str = target.ToString();

    } else
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid difficulty");

    instance_of_cstratumparams.setTarget(arith_uint256(diff_str));

    UniValue obj(UniValue::VOBJ);
    obj.push_back(Pair("target", diff_str));

    CBlockIndex tmp_index;
    tmp_index.nBits = arith_uint256(diff_str).GetCompact();

    double new_hush_diff = GetDifficulty(&tmp_index);
    obj.push_back(Pair("hush_diff_str", strprintf("%g",new_hush_diff)));
    obj.push_back(Pair("hush_diff", new_hush_diff));

    return obj;
};

UniValue rpc_stratum_getclientscount (const UniValue& params, bool fHelp, const CPubKey& mypk) {

    if (fHelp || params.size() != 0)
        throw std::runtime_error(
            "stratum_getclientscount\n"
            "Show the the number of stratum clients.\n"
            "\nExamples:\n"
            + HelpExampleCli("stratum_getclientscount", "")
            + HelpExampleRpc("stratum_getclientscount", "")
        );
    UniValue obj(UniValue::VOBJ);
    uint64_t subscriptionsSize = subscriptions.size();
    obj.push_back(Pair("total", subscriptionsSize));

    return obj;
};

static const CRPCCommand commands[] =
{ //  category              name                       actor (function)              okSafeMode
  //  --------------------- ------------------------   -----------------------       ----------
    { "stratum",            "stratum_updatework",      &rpc_stratum_updatework,      true },
    { "stratum",            "stratum_getdifficulty",   &rpc_stratum_getdifficulty,   true },
    { "stratum",            "stratum_setdifficulty",   &rpc_stratum_setdifficulty,   true },
    { "stratum",            "stratum_getclientscount", &rpc_stratum_getclientscount, true },
};

void RegisterStratumRPCCommands(CRPCTable &tableRPC)
{
    for (unsigned int vcidx = 0; vcidx < ARRAYLEN(commands); vcidx++)
        tableRPC.appendCommand(commands[vcidx].name, &commands[vcidx]);
}

// End of File