/*
 * This file is part of the Flowee project
 * Copyright (c) 2009-2010 Satoshi Nakamoto
 * Copyright (c) 2009-2015 The Bitcoin Core developers
 * Copyright (C) 2019-2024 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#if defined(HAVE_CONFIG_H)
#include "config/flowee-config.h"
#endif

#include "init.h"
#include <SettingsDefaults.h>

#include "Application.h"
#include "addrman.h"
#include "amount.h"
#include "chain.h"
#include "chainparams.h"
#include "checkpoints.h"
#include "compat/sanity.h"
#include "DoubleSpendProofStorage.h"
#include "httpserver.h"
#include "httprpc.h"
#include <primitives/PrivateKey.h>
#include "main.h"
#include "miner.h"
#include "net.h"
#include "policy/policy.h"
#include "rpcserver.h"
#include "script/standard.h"
#include "script/sigcache.h"
#include "scheduler.h"
#include "BlocksDB.h"
#include "txmempool.h"
#include "torcontrol.h"
#include "UiInterface.h"
#include <util.h>
#include <utiltime.h>
#include "serverutil.h"
#include <utilmoneystr.h>
#include <utilstrencodings.h>
#include "txorphancache.h"
#include "validationinterface.h"
#include <validation/Engine.h>
#include <cstdint>
#include <cstdio>

#ifndef WIN32
#include <csignal>
#include <sys/resource.h>
#endif

#include <validation/VerifyDB.h>
#include <utxo/UnspentOutputDatabase.h>
#include <boost/algorithm/string/classification.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string/case_conv.hpp> // for to_lower()
#include <boost/lexical_cast.hpp>
#include <boost/filesystem.hpp>
#include <boost/function.hpp>
#include <boost/interprocess/sync/file_lock.hpp>
#include <boost/thread.hpp>
#include <openssl/crypto.h>
#include <boost/date_time/posix_time/posix_time.hpp>


#if ENABLE_ZMQ
#include "zmq/zmqnotificationinterface.h"
#endif

#if ENABLE_ZMQ
static CZMQNotificationInterface* pzmqNotificationInterface = NULL;
#endif

#ifdef WIN32
// Win32 LevelDB doesn't use filedescriptors, and the ones used for
// accessing block files don't count towards the fd_set size limit
// anyway.
#define MIN_CORE_FILEDESCRIPTORS 0
#else
#define MIN_CORE_FILEDESCRIPTORS 1000
#endif

/** Used to pass flags to the Bind() function */
enum BindFlags {
    BF_NONE         = 0,
    BF_EXPLICIT     = (1U << 0),
    BF_REPORT_ERROR = (1U << 1),
    BF_WHITELIST    = (1U << 2),
};

CClientUIInterface uiInterface; // Declared but not defined in ui_interface.h

namespace {
/**
 * this function tries to raise the file descriptor limit to the requested number.
 * It returns the actual file descriptor limit (which may be more or less than nMinFD)
 */
int RaiseFileDescriptorLimit(int nMinFD) {
#if defined(WIN32)
    return 2048;
#else
    struct rlimit limitFD;
    if (getrlimit(RLIMIT_NOFILE, &limitFD) != -1) {
        if (limitFD.rlim_cur < (rlim_t)nMinFD) {
            limitFD.rlim_cur = nMinFD;
            if (limitFD.rlim_cur > limitFD.rlim_max)
                limitFD.rlim_cur = limitFD.rlim_max;
            setrlimit(RLIMIT_NOFILE, &limitFD);
            getrlimit(RLIMIT_NOFILE, &limitFD);
        }
        return limitFD.rlim_cur;
    }
    return nMinFD; // getrlimit failed, assume it's fine
#endif
}

#ifndef WIN32
boost::filesystem::path GetPidFile()
{
    boost::filesystem::path pathPidFile(GetArg("-pid", Settings::hubPidFilename()));
    if (!pathPidFile.is_absolute()) pathPidFile = GetDataDir() / pathPidFile;
    return pathPidFile;
}

void CreatePidFile(const boost::filesystem::path &path, pid_t pid)
{
    FILE* file = fopen(path.string().c_str(), "w");
    if (file)
    {
        fprintf(file, "%d\n", pid);
        fclose(file);
    }
}
#endif

void ShrinkDebugFile()
{
    // Scroll hub.log if it's getting too big
    boost::filesystem::path pathLog = GetDataDir() / "hub.log";
    FILE* file = fopen(pathLog.string().c_str(), "r");
    if (file && boost::filesystem::file_size(pathLog) > 10 * 1000000)
    {
        // Restart the file with some of the end
        std::vector <char> vch(200000,0);
        fseek(file, -((long)vch.size()), SEEK_END);
        int nBytes = fread(begin_ptr(vch), 1, vch.size(), file);
        fclose(file);

        file = fopen(pathLog.string().c_str(), "w");
        if (file)
        {
            fwrite(begin_ptr(vch), 1, nBytes, file);
            fclose(file);
        }
    }
    else if (file != NULL)
        fclose(file);
}


}

//////////////////////////////////////////////////////////////////////////////
//
// Shutdown
//

//
// Thread management and startup/shutdown:
//
// The network-processing threads are all part of a thread group
// created by AppInit() or the Qt main() function.
//
// A clean exit happens when StartShutdown() or the SIGTERM
// signal handler sets fRequestShutdown, which triggers
// the DetectShutdownThread(), which interrupts the main thread group.
// DetectShutdownThread() then exits, which causes AppInit() to
// continue (it .joins the shutdown thread).
// Shutdown() is then
// called to clean up database connections, and stop other
// threads that should only be stopped after the main network-processing
// threads have exited.
//
// Note that if running -daemon the parent process returns from AppInit2
// before adding any threads to the threadGroup, so .join_all() returns
// immediately and the parent exits from main().
//
// Shutdown for Qt is very similar, only it uses a QTimer to detect
// fRequestShutdown getting set, and then does the normal Qt
// shutdown thing.
//

volatile bool fRequestShutdown = false;

void StartShutdown()
{
    fRequestShutdown = true;
}
bool ShutdownRequested()
{
    return fRequestShutdown;
}

static boost::scoped_ptr<ECCVerifyHandle> globalVerifyHandle;

UnspentOutputDatabase *g_utxo = nullptr;

void Interrupt(boost::thread_group& threadGroup)
{
    InterruptHTTPServer();
    InterruptRPC();
    InterruptTorControl();
    threadGroup.interrupt_all();
}

void Shutdown()
{
    logCritical(Log::Bitcoin) << "Shutdown in progress...";
    static CCriticalSection cs_Shutdown;
    TRY_LOCK(cs_Shutdown, lockShutdown);
    if (!lockShutdown)
        return;

    /// Note: Shutdown() must be able to handle cases in which AppInit2() failed part of the way,
    /// for example if the data directory was found to be locked.
    /// Be sure that anything that writes files or flushes caches only does this if the respective
    /// module was initialized.
    RenameThread("hub-shutoff");
    mempool.AddTransactionsUpdated(1);

    StopHTTPRPC();
    StopREST();
    StopRPC();
    StopHTTPServer();
    Mining::Stop();
    StopNode();
    StopTorControl();
    UnregisterNodeSignals(GetNodeSignals());

    Application::quit(0);
    Application::exec(); // waits for threads to finish.

    {
        LOCK(cs_main);
        FlushStateToDisk();
        delete g_utxo;
        g_utxo = nullptr;
        Blocks::DB::shutdown();
    }

#if ENABLE_ZMQ
    if (pzmqNotificationInterface) {
        ValidationNotifier().removeListener(pzmqNotificationInterface);
        delete pzmqNotificationInterface;
        pzmqNotificationInterface = NULL;
    }
#endif

#ifndef WIN32
    try {
        boost::filesystem::remove(GetPidFile());
    } catch (const boost::filesystem::filesystem_error& e) {
        logCritical(Log::Bitcoin) << "Shutdown: Unable to remove pidfile:" <<  e;
    }
#endif
    ValidationNotifier().removeAll();
    globalVerifyHandle.reset();
    ECC_Stop();
    logCritical(Log::Bitcoin) << "Shutdown: done";
}

/**
 * Signal handlers are very limited in what they are allowed to do, so:
 */
void HandleSIGTERM(int)
{
    fRequestShutdown = true;
}

void HandleSIGHUP(int)
{
    Log::Manager::instance()->reopenLogFiles();
    Log::Manager::instance()->parseConfig(GetConfigFile("logs.conf"), GetDataDir(true) / "hub.log");
}

bool static InitError(const std::string &str)
{
    uiInterface.ThreadSafeMessageBox(str, "", CClientUIInterface::MSG_ERROR);
    return false;
}

bool static InitWarning(const std::string &str)
{
    uiInterface.ThreadSafeMessageBox(str, "", CClientUIInterface::MSG_WARNING);
    return true;
}

bool static Bind(const CService &addr, unsigned int flags) {
    if (!(flags & BF_EXPLICIT) && IsLimited(addr))
        return false;
    std::string strError;
    if (!BindListenPort(addr, strError, (flags & BF_WHITELIST) != 0)) {
        if (flags & BF_REPORT_ERROR)
            return InitError(strError);
        return false;
    }
    return true;
}

void OnRPCStopped()
{
    cvBlockChange.notify_all();
    logInfo(Log::RPC) << "RPC stopped.";
}

void OnRPCPreCommand(const CRPCCommand& cmd)
{
    // Observe safe mode
    std::string strWarning = GetWarnings("rpc");
    if (strWarning != "" && !GetBoolArg("-disablesafemode", Settings::DefaultDisableSafemode) &&
        !cmd.okSafeMode)
        throw JSONRPCError(RPC_FORBIDDEN_BY_SAFE_MODE, std::string("Safe mode: ") + strWarning);
}

static void BlockNotifyCallback(bool initialSync, const CBlockIndex *pBlockIndex)
{
    if (initialSync || !pBlockIndex)
        return;

    std::string strCmd = GetArg("-blocknotify", "");

    boost::replace_all(strCmd, "%s", pBlockIndex->GetBlockHash().GetHex());
    boost::thread t(runCommand, strCmd); // thread runs free
}


/** Sanity checks
 *  Ensure that Bitcoin is running in a usable environment with all
 *  necessary library support.
 */
bool InitSanityCheck(void)
{
    if(!ECC_InitSanityCheck()) {
        InitError("Elliptic curve cryptography sanity check failure. Aborting.");
        return false;
    }
    if (!glibc_sanity_test() || !glibcxx_sanity_test())
        return false;

    return true;
}

bool AppInitServers()
{
    RPCServer::OnStopped(&OnRPCStopped);
    RPCServer::OnPreCommand(&OnRPCPreCommand);
    if (!InitHTTPServer())
        return false;
    StartRPC();
    if (!StartHTTPRPC())
        return false;
    if (GetBoolArg("-rest", Settings::DefaultRestEnable))
        StartREST();
    StartHTTPServer();
    return true;
}

// Parameter interaction based on rules
void InitParameterInteraction()
{
    // when specifying an explicit binding address, you want to listen on it
    // even when -connect or -proxy is specified
    if (mapArgs.count("-bind")) {
        if (SoftSetBoolArg("-listen", true))
            logCritical(Log::Net) << "parameter interaction: -bind set -> setting -listen=1";
    }
    if (mapArgs.count("-whitebind")) {
        if (SoftSetBoolArg("-listen", true))
            logCritical(Log::Net) << "parameter interaction: -whitebind set -> setting -listen=1";
    }

    if (mapArgs.count("-connect") && mapMultiArgs["-connect"].size() > 0) {
        // when only connecting to trusted nodes, do not seed via DNS, or listen by default
        if (SoftSetBoolArg("-dnsseed", false))
            logCritical(Log::Net) << "parameter interaction: -connect set -> setting -dnsseed=0";
        if (SoftSetBoolArg("-listen", false))
            logCritical(Log::Net) << "parameter interaction: -connect set -> setting -listen=0";
    }

    if (mapArgs.count("-proxy")) {
        // to protect privacy, do not listen by default if a default proxy server is specified
        if (SoftSetBoolArg("-listen", false))
            logCritical(Log::Proxy) << "parameter interaction: -proxy set -> setting -listen=0";
        // to protect privacy, do not use UPNP when a proxy is set. The user may still specify -listen=1
        // to listen locally, so don't rely on this happening through -listen below.
        if (SoftSetBoolArg("-upnp", false))
            logCritical(Log::Proxy) << "parameter interaction: -proxy set -> setting -upnp=0";
        // to protect privacy, do not discover addresses by default
        if (SoftSetBoolArg("-discover", false))
            logCritical(Log::Proxy) << "parameter interaction: -proxy set -> setting -discover=0";
    }

    if (!GetBoolArg("-listen", DEFAULT_LISTEN)) {
        // do not map ports or try to retrieve public IP when not listening (pointless)
        if (SoftSetBoolArg("-upnp", false))
            logCritical(Log::Net) << "parameter interaction: -listen=0 -> setting -upnp=0";
        if (SoftSetBoolArg("-discover", false))
            logCritical(Log::Net) << "parameter interaction: -listen=0 -> setting -discover=0";
        if (SoftSetBoolArg("-listenonion", false))
            logCritical(Log::Net) << "parameter interaction: -listen=0 -> setting -listenonion=0";
    }

    if (mapArgs.count("-externalip")) {
        // if an explicit public IP is specified, do not try to find others
        if (SoftSetBoolArg("-discover", false))
            logCritical(Log::Net) << "parameter interaction: -externalip set -> setting -discover=false";
    }

    // disable walletbroadcast and whitelistrelay in blocksonly mode
    if (GetBoolArg("-blocksonly", Settings::DefaultBlocksOnly)) {
        if (SoftSetBoolArg("-whitelistrelay", false))
            logCritical(Log::Net) << "parameter interaction: -blocksonly=true -> setting -whitelistrelay=false";
    }

    // Forcing relay from whitelisted hosts implies we will accept relays from them in the first place.
    if (GetBoolArg("-whitelistforcerelay", Settings::DefaultWhitelistForceRelay)) {
        if (SoftSetBoolArg("-whitelistrelay", true))
            logCritical(Log::Net) << "parameter interaction: -whitelistforcerelay=true -> setting -whitelistrelay=true";
    }

    auto miningSize = GetArg("-blockmaxsize", -1);
    if (miningSize > 0x7FFFFFFF) { // overflow
        logCritical(Log::Mining) << "parameter -blockmaxsize is too large. Max is 31bit int";
        throw std::runtime_error("invalid parameter passed to -blockmaxsize");
    }

    int32_t acceptSize = Policy::blockSizeAcceptLimit();
    if (GetBoolArg("-scalenet", false) && acceptSize < 268435456) {
        logCritical(Log::Net) << "parameter interaction: -scalenet -> setting -blockmaxsize";
        miningSize = acceptSize = 268435456;
        SoftSetArg("-blocksizeacceptlimit", "270");
        SoftSetArg("-blockmaxsize", "268435456");
    }
    if ((int) miningSize > acceptSize) {
        if (SoftSetArg("-blocksizeacceptlimit", boost::lexical_cast<std::string>((miningSize + 100000) / 1E6)))
            logCritical(Log::Net) << "parameter interaction: -blockmaxsize  N -> setting -blockacceptlimit=N";
        else
            throw std::runtime_error("Block Accept setting smaller than block mining size. Please adjust and restart");
    }
    assert(Policy::blockSizeAcceptLimit() >= miningSize);

    const int64_t mempoolMaxSize = GetArg("-maxmempool", Settings::DefaultMaxMempoolSize) * 4500000;
    if (mempoolMaxSize < miningSize * 4) {
        if (SoftSetArg("-maxmempool", boost::lexical_cast<std::string>(miningSize * 4)))
            logCritical(Log::Net) << "parameter interaction: -blockmaxsize  N -> setting -maxmempool=4N";
    }

}

void InitLogging()
{
    fLogIPs = GetBoolArg("-logips", DEFAULT_LOGIPS);

    auto *manager = Log::Manager::instance();
#if 1
    manager->parseConfig(GetConfigFile("logs.conf"), GetDataDir(true) / "hub.log");
#else
    // this is high speed logging. Possibly filling up your memory, only useful for timing specific work.
    manager->clearChannels();
    manager->addFastLogChannel(GetDataDir(true) / "hub.log");
#endif
    logCritical(Log::Bitcoin) << "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
    logCritical(Log::Bitcoin) << "Flowee the Hub version " << CLIENT_BUILD.c_str()
                              << "Built:" << CLIENT_DATE.c_str();
}

/** Initialize bitcoin.
 *  @pre Parameters should be parsed and config file should be read.
 */
bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
{
    // ********************************************************* Step 1: setup
#ifdef _MSC_VER
    // Turn off Microsoft heap dump noise
    _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_FILE);
    _CrtSetReportFile(_CRT_WARN, CreateFileA("NUL", GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, 0));
#endif
#if _MSC_VER >= 1400
    // Disable confusing "helpful" text message on abort, Ctrl-C
    _set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
#endif
#ifdef WIN32
    // Enable Data Execution Prevention (DEP)
    // Minimum supported OS versions: WinXP SP3, WinVista >= SP1, Win Server 2008
    // A failure is non-critical and needs no further attention!
#ifndef PROCESS_DEP_ENABLE
    // We define this here, because GCCs winbase.h limits this to _WIN32_WINNT >= 0x0601 (Windows 7),
    // which is not correct. Can be removed, when GCCs winbase.h is fixed!
#define PROCESS_DEP_ENABLE 0x00000001
#endif
    typedef BOOL (WINAPI *PSETPROCDEPPOL)(DWORD);
    PSETPROCDEPPOL setProcDEPPol = (PSETPROCDEPPOL)GetProcAddress(GetModuleHandleA("Kernel32.dll"), "SetProcessDEPPolicy");
    if (setProcDEPPol != NULL) setProcDEPPol(PROCESS_DEP_ENABLE);
#endif

#ifdef USE_UNSAFE_RANDOM
    /* Intializes random number generator in case the operator wanted non-safe random */
    srand(unsigned(boost::posix_time::microsec_clock::local_time().time_of_day().total_microseconds()));
#endif

    if (!SetupNetworking())
        return InitError("Initializing networking failed");

#ifndef WIN32

    // Clean shutdown on SIGTERM
    struct sigaction sa;
    sa.sa_handler = HandleSIGTERM;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sigaction(SIGTERM, &sa, NULL);
    sigaction(SIGINT, &sa, NULL);

    // Reopen hub.log on SIGHUP
    struct sigaction sa_hup;
    sa_hup.sa_handler = HandleSIGHUP;
    sigemptyset(&sa_hup.sa_mask);
    sa_hup.sa_flags = 0;
    sigaction(SIGHUP, &sa_hup, NULL);

    // Ignore SIGPIPE, otherwise it will bring the daemon down if the client closes unexpectedly
    signal(SIGPIPE, SIG_IGN);
#endif

    // ********************************************************* Step 2: parameter interactions
    const CChainParams& chainparams = Params();

    // also see: InitParameterInteraction()

    // Make sure enough file descriptors are available
    int nBind = std::max((int)mapArgs.count("-bind") + (int)mapArgs.count("-whitebind"), 1);
    int nUserMaxConnections = GetArg("-maxconnections", Settings::DefaultMaxPeerConnections);
    nMaxConnections = std::max(nUserMaxConnections, 0);

    // Trim requested connection counts, to fit into system limitations
    int nFD = RaiseFileDescriptorLimit(nMaxConnections + MIN_CORE_FILEDESCRIPTORS + nBind);
    nMaxConnections = std::max(std::min(nMaxConnections, (int)(nFD - nBind - MIN_CORE_FILEDESCRIPTORS)), 0);
    logFatal() << "num file descriptors:" << nFD;
    if (nFD < MIN_CORE_FILEDESCRIPTORS)
        return InitError(_("Not enough file descriptors available."));
    nMaxConnections = std::min(nFD - MIN_CORE_FILEDESCRIPTORS, nMaxConnections);

    if (nMaxConnections < nUserMaxConnections)
        InitWarning(strprintf(_("Reducing -maxconnections from %d to %d, because of system limitations."), nUserMaxConnections, nMaxConnections));

    // ********************************************************* Step 3: parameter-to-internal-flags

    fCheckpointsEnabled = GetBoolArg("-checkpoints", Settings::DefaultCheckpointsEnabled);

    // mempool limits
    int64_t nMempoolSizeMax = GetArg("-maxmempool", Settings::DefaultMaxMempoolSize) * 1000000;
    int64_t nMempoolSizeMin = GetArg("-limitdescendantsize", Settings::DefaultDescendantSizeLimit) * 1000 * 40;
    if (nMempoolSizeMax < 0 || nMempoolSizeMax < nMempoolSizeMin)
        return InitError(strprintf(_("-maxmempool must be at least %d MB"), std::ceil(nMempoolSizeMin / 1000000.0)));

    fServer = GetBoolArg("-server", false);

    nConnectTimeout = GetArg("-timeout", Settings::DefaultConnectTimeout);
    if (nConnectTimeout <= 0)
        nConnectTimeout = Settings::DefaultConnectTimeout;

    // Fee-per-kilobyte amount considered the same as "free"
    // If you are mining, be careful setting this:
    // if you set it to zero then
    // a transaction spammer can cheaply fill blocks using
    // 1-satoshi-fee transactions. It should be set above the real
    // cost to you of processing a transaction.
    if (mapArgs.count("-minrelaytxfee"))
    {
        int64_t n = 0;
        if (ParseMoney(mapArgs["-minrelaytxfee"], n) && n > 0) {
            logCritical(Log::Bitcoin) << "Setting min relay Transaction fee to" << n << "satoshi";
            ::minRelayTxFee = CFeeRate(n);
        } else {
            return InitError(strprintf(_("Invalid amount for -minrelaytxfee=<amount>: '%s'"), mapArgs["-minrelaytxfee"]));
        }
    }

    fRequireStandard = !GetBoolArg("-acceptnonstdtxn", !Params().RequireStandard());

    fIsBareMultisigStd = GetBoolArg("-permitbaremultisig", Settings::DefaultPermitBareMultisig);
    fAcceptDatacarrier = GetBoolArg("-datacarrier", Settings::DefaultAcceptDataCarrier);
    nMaxDatacarrierBytes = GetArg("-datacarriersize", Settings::MaxOpReturnRelay);

    // Option to startup with mocktime set (used for regression testing):
    SetMockTime(GetArg("-mocktime", 0)); // SetMockTime(0) is a no-op

    if (GetBoolArg("-peerbloomfilters", true))
        nLocalServices |= NODE_BLOOM;

    if (GetBoolArg("-use-thinblocks", false))
        nLocalServices |= NODE_XTHIN;
    if (Params().NetworkIDString() == CBaseChainParams::MAIN) {
        if (Policy::blockSizeAcceptLimit() < 8000000)
            return InitError("The block size accept limit is too low, the minimum is 8MB. The Hub is shutting down.");
        if (GetArg("-blockmaxsize", Settings::DefaultBlockMAxSize) <= 1000000)
            return InitError("The maxblocksize mining limit is too low, it should be over 1MB. The Hub is shutting down.");
    }
    else if (Params().NetworkIDString() == CBaseChainParams::REGTEST) { // setup for testing to not use so much disk space.
        UnspentOutputDatabase::setSmallLimits();
    }

    // ********************************************************* Step 4: application initialization: dir lock, daemonize, pidfile, hub log

    // Initialize elliptic curve code
    ECC_Start();
    globalVerifyHandle.reset(new ECCVerifyHandle());

    // Initialize SigCache
    InitSignatureCache();

    // Sanity check
    if (!InitSanityCheck())
        return InitError(_("Initialization sanity check failed. The Hub is shutting down."));

    std::string strDataDir = GetDataDir().string();
    // Make sure only a single Bitcoin process is using the data directory.
    boost::filesystem::path pathLockFile = GetDataDir() / ".lock";
    FILE* file = fopen(pathLockFile.string().c_str(), "a"); // empty lock file; created if it doesn't exist.
    if (file) fclose(file);

    try {
        static boost::interprocess::file_lock lock(pathLockFile.string().c_str());
        if (!lock.try_lock())
            return InitError(strprintf(_("Cannot obtain a lock on data directory %s. The Hub is probably already running."), strDataDir));
    } catch(const boost::interprocess::interprocess_exception& e) {
        return InitError(strprintf(_("Cannot obtain a lock on data directory %s. The Hub is probably already running.") + " %s.", strDataDir, e.what()));
    }

#ifndef WIN32
    CreatePidFile(GetPidFile(), getpid());
#endif
    if (GetBoolArg("-shrinkdebugfile", true))
        ShrinkDebugFile();

    logCritical(Log::Bitcoin) << "Startup time:" << DateTimeStrFormat("%Y-%m-%d %H:%M:%S", GetTime());
    logCritical(Log::Bitcoin) << "Using data directory" << strDataDir;
    logCritical(Log::Bitcoin) << "Using config file" << GetConfigFile().string();
    logCritical(Log::Bitcoin) << "Using log-config file" << GetConfigFile("logs.conf").string();
    logInfo(Log::Net) << "Using at most" << nMaxConnections  << "connections.";
    logInfo(Log::Internals) << nFD << "file descriptors available";
    std::ostringstream strErrors;

    // Start the lightweight task scheduler thread
    CScheduler::Function serviceLoop = std::bind(&CScheduler::serviceQueue, &scheduler);
    threadGroup.create_thread(std::bind(&TraceThread<CScheduler::Function>, "scheduler", serviceLoop));

    /* Start the RPC server already.  It will be started in "warmup" mode
     * and not really process calls already (but it will signify connections
     * that the server is there and will be ready later).  Warmup mode will
     * be disabled when initialisation is finished.
     */
    if (fServer)
    {
        uiInterface.InitMessage.connect(SetRPCWarmupStatus);
        if (!AppInitServers())
            return InitError(_("Unable to start HTTP server. See hub log for details."));
    }

    Application::instance()->validation()->enableFeeResolveForMetaData(GetBoolArg("-feesmetadata", false));
    Application::instance()->validation()->setMempool(&mempool);
    scheduler.scheduleEvery(std::bind(&DoubleSpendProofStorage::periodicCleanup,  mempool.doubleSpendProofStorage()), 60);

    // ********************************************************* Step 5: load block chain

    bool fReindex = GetBoolArg("-reindex", false);
    bool fLoaded = false;
    int64_t nStart;
    while (!fLoaded) {
        bool fReset = fReindex;
        std::string strLoadError;

        uiInterface.InitMessage(_("Loading block index..."));

        nStart = GetTimeMillis();
        do {
            try {
                UnloadBlockIndex();
                delete g_utxo;
                g_utxo = nullptr;
                Blocks::DB::createInstance(40 << 20, fReindex, &scheduler);
                const auto utxoDir = GetDataDir() / "unspent";
                if (fReindex) {
                    boost::system::error_code error;
                    // delete all files under unspent. Don't delete itself, it may be a symlink.
                    boost::filesystem::directory_iterator iter(utxoDir, error);
                    while (!error && iter != boost::filesystem::directory_iterator()) {
                        boost::filesystem::remove_all(*iter, error);
                        ++iter;
                    }
                    if (error) {
                        // then try to delete the utxo dir itself.
                        boost::filesystem::remove_all(utxoDir, error);
                        if (error) {
                            fRequestShutdown = true;
                            logFatal(Log::Bitcoin) << "Can't remove the unspent dir to do a reindex" << error.message();
                            break;
                        }
                    }
                }
                g_utxo = new UnspentOutputDatabase(Application::instance()->ioContext(), utxoDir);
                mempool.setUtxo(g_utxo);
                if (fReindex)
                    Blocks::DB::instance()->setReindexing(Blocks::ScanningFiles);

                if (!fReindex && !LoadBlockIndexDB(g_utxo)) {
                    strLoadError = _("Error loading block database");
                    break;
                }
                Application::instance()->validation()->setBlockchain(&chainActive);

                while (!fReindex) {
                    auto tip = Blocks::Index::get(g_utxo->blockId());
                    // now lets see if the utxo and the block-database like each other
                    if (tip) {
                        pindexBestHeader = Blocks::DB::instance()->headerChain().Tip();
                        chainActive.SetTip(tip);
                        // Set the chain again after it received a Tip()
                        Application::instance()->validation()->setBlockchain(&chainActive);

                        // verify basics
                        if (!VerifyDB().verifyDB(GetArg("-checklevel", Settings::DefaultCheckLevel),
                                                 GetArg("-checkblocks", Settings::DefaultCheckBlocks))) {
                            // verify failed, go to an older state.
                            tip = nullptr;
                        }
                    } else if (g_utxo->blockId().IsNull()) { // first start.
                        break;
                    } else {
                        logCritical(Log::Bitcoin) << "UTXO has tip which we don't have in the block-index. UTXO best block:"
                                                  << g_utxo->blockId() << g_utxo->blockheight();
                    }

                    if (tip) { // yes, lets go!
                        logCritical(Log::Bitcoin) << "LoadBlockIndexDB: hashBestChain:" << tip->GetBlockHash()
                                                 << "height:" << tip->nHeight
                                                 << "nTx:" << tip->nChainTx
                                                 << "date:" << DateTimeStrFormat("%Y-%m-%d %H:%M:%S", tip->GetBlockTime()).c_str()
                                                 << "header height:" << Blocks::DB::instance()->headerChain().Height();
                        break;
                    } else {
                        // they don't like each other. Try an older UTXO state.
                        if (!g_utxo->loadOlderState()) {
                            fRequestShutdown = true;
                            break;
                        }
                    }
                }
                if (fRequestShutdown)
                    break;

                // Check whether we need to continue reindexing
                fReindex = fReindex || Blocks::DB::instance()->reindexing() != Blocks::NoReindex;

                // If the loaded chain has a wrong genesis, bail out immediately
                // (we're likely using a testnet datadir, or the other way around).
                if (!Blocks::Index::empty() && !Blocks::Index::exists(chainparams.GetConsensus().hashGenesisBlock))
                    return InitError(_("Incorrect or no genesis block found. Wrong datadir for network?"));

                // Initialize the block index (no-op if non-empty database was already loaded)
                if (!InitBlockIndex(chainparams)) {
                    strLoadError = _("Error initializing block database");
                    break;
                }

                uiInterface.InitMessage(_("Verifying blocks..."));
                {
                    LOCK(cs_main);
                    CBlockIndex* tip = chainActive.Tip();
                    if (tip && tip->nTime > GetAdjustedTime() + 2 * 60 * 60) {
                        strLoadError = _("The block database contains a block which appears to be from the future. "
                                "This may be due to your computer's date and time being set incorrectly. "
                                "Only rebuild the block database if you are sure that your computer's date and time are correct");
                        break;
                    }
                }
                scheduler.scheduleEvery(std::bind(&UnspentOutputDatabase::saveCaches, g_utxo), 5 * 60);
            } catch (const std::exception& e) {
                logWarning() << e;
                strLoadError = _("Error opening block database");
                break;
            }

            fLoaded = true;
        } while(false);

        if (fRequestShutdown)
            break;

        if (!fLoaded) {
            // first suggest a reindex
            if (!fReset) {
                bool fRet = uiInterface.ThreadSafeMessageBox(
                    strLoadError + ".\n\n" + _("Do you want to rebuild the block database now?"),
                    "", CClientUIInterface::MSG_ERROR | CClientUIInterface::BTN_ABORT);
                if (fRet) {
                    fReindex = true;
                    Blocks::DB::instance()->setReindexing(Blocks::ScanningFiles);
                    fRequestShutdown = false;
                } else {
                    logFatal(Log::Bitcoin) << "Aborted block database rebuild. Exiting.";
                    return false;
                }
            } else {
                return InitError(strLoadError);
            }
        }
    }

    // As LoadBlockIndex can take several minutes, it's possible the user
    // requested to kill the GUI during the last operation. If so, exit.
    // As the program has not fully started yet, Shutdown() is possibly overkill.
    if (fRequestShutdown)
    {
        logFatal(Log::Bitcoin) << "Shutdown requested. Exiting.";
        return false;
    }
    logInfo(Log::Bench).nospace() << "block index load took: " << GetTimeMillis() - nStart << "ms";

    if (Params().NetworkIDString() != CBaseChainParams::REGTEST) { // For non-testing setups, keep tracks of disk-space free stats.
        auto &dsc = Application::instance()->diskSpaceChecker();
        if (!dsc.enoughSpaceAvailable())
            return InitError("Not enough disk space available to safely start");
        dsc.start(); // keep checking
    }

    // ********************************************************* Step 6: network initialization

    CTxOrphanCache::instance()->setLimit((unsigned int)std::max((int64_t)0, GetArg("-maxorphantx", Settings::DefaultMaxOrphanTransactions)));

    RegisterNodeSignals(GetNodeSignals());

    if (mapArgs.count("-onlynet")) {
        std::set<CNetAddr::Network> nets;
        for (const std::string& snet : mapMultiArgs["-onlynet"]) {
            CNetAddr::Network net = ParseNetwork(snet);
            if (net == CNetAddr::NET_UNROUTABLE)
                return InitError(strprintf(_("Unknown network specified in -onlynet: '%s'"), snet));
            nets.insert(net);
        }
        for (int n = 0; n < CNetAddr::NET_MAX; n++) {
            CNetAddr::Network net = (CNetAddr::Network)n;
            if (!nets.count(net))
                SetLimited(net);
        }
    }

    if (mapArgs.count("-whitelist")) {
        for (const std::string& net : mapMultiArgs["-whitelist"]) {
            CSubNet subnet(net);
            if (!subnet.IsValid())
                return InitError(strprintf(_("Invalid netmask specified in -whitelist: '%s'"), net));
            CNode::AddWhitelistedRange(subnet);
        }
    }

    bool proxyRandomize = GetBoolArg("-proxyrandomize", Settings::DefaultProxyRandomize);
    // -proxy sets a proxy for all outgoing network traffic
    // -noproxy (or -proxy=0) as well as the empty string can be used to not set a proxy, this is the default
    std::string proxyArg = GetArg("-proxy", "");
    SetLimited(CNetAddr::NET_TOR);
    if (proxyArg != "" && proxyArg != "0") {
        proxyType addrProxy = proxyType(CService(proxyArg, 9050), proxyRandomize);
        if (!addrProxy.IsValid())
            return InitError(strprintf(_("Invalid -proxy address: '%s'"), proxyArg));

        SetProxy(CNetAddr::NET_IPV4, addrProxy);
        SetProxy(CNetAddr::NET_IPV6, addrProxy);
        SetProxy(CNetAddr::NET_TOR, addrProxy);
        SetNameProxy(addrProxy);
        SetLimited(CNetAddr::NET_TOR, false); // by default, -proxy sets onion as reachable, unless -noonion later
    }

    // -onion can be used to set only a proxy for .onion, or override normal proxy for .onion addresses
    // -noonion (or -onion=0) disables connecting to .onion entirely
    // An empty string is used to not override the onion proxy (in which case it defaults to -proxy set above, or none)
    std::string onionArg = GetArg("-onion", "");
    if (onionArg != "") {
        if (onionArg == "0") { // Handle -noonion/-onion=0
            SetLimited(CNetAddr::NET_TOR); // set onions as unreachable
        } else {
            proxyType addrOnion = proxyType(CService(onionArg, 9050), proxyRandomize);
            if (!addrOnion.IsValid())
                return InitError(strprintf(_("Invalid -onion address: '%s'"), onionArg));
            SetProxy(CNetAddr::NET_TOR, addrOnion);
            SetLimited(CNetAddr::NET_TOR, false);
        }
    }

    // see Step 2: parameter interactions for more information about these
    fListen = GetBoolArg("-listen", DEFAULT_LISTEN);
    fDiscover = GetBoolArg("-discover", true);
    fNameLookup = GetBoolArg("-dns", Settings::DefaultNameLookup);

    bool fBound = false;
    if (fListen) {
        if (mapArgs.count("-bind") || mapArgs.count("-whitebind")) {
            for (const std::string& strBind : mapMultiArgs["-bind"]) {
                CService addrBind;
                if (!Lookup(strBind.c_str(), addrBind, GetListenPort(), false))
                    return InitError(strprintf(_("Cannot resolve -bind address: '%s'"), strBind));
                fBound |= Bind(addrBind, (BF_EXPLICIT | BF_REPORT_ERROR));
            }
            for (const std::string& strBind : mapMultiArgs["-whitebind"]) {
                CService addrBind;
                if (!Lookup(strBind.c_str(), addrBind, 0, false))
                    return InitError(strprintf(_("Cannot resolve -whitebind address: '%s'"), strBind));
                if (addrBind.GetPort() == 0)
                    return InitError(strprintf(_("Need to specify a port with -whitebind: '%s'"), strBind));
                fBound |= Bind(addrBind, (BF_EXPLICIT | BF_REPORT_ERROR | BF_WHITELIST));
            }
        }
        else {
            struct in_addr inaddr_any;
            inaddr_any.s_addr = INADDR_ANY;
            fBound |= Bind(CService(in6addr_any, GetListenPort()), BF_NONE);
            fBound |= Bind(CService(inaddr_any, GetListenPort()), !fBound ? BF_REPORT_ERROR : BF_NONE);
        }
        if (!fBound)
            return InitError(_("Failed to listen on any port. Use -listen=0 if you want this."));
    }

    if (mapArgs.count("-externalip")) {
        for (const std::string& strAddr : mapMultiArgs["-externalip"]) {
            CService addrLocal(strAddr, GetListenPort(), fNameLookup);
            if (!addrLocal.IsValid())
                return InitError(strprintf(_("Cannot resolve -externalip address: '%s'"), strAddr));
            AddLocal(CService(strAddr, GetListenPort(), fNameLookup), LOCAL_MANUAL);
        }
    }

    for (const std::string& strDest : mapMultiArgs["-seednode"])
        AddOneShot(strDest);

#if ENABLE_ZMQ
    pzmqNotificationInterface = CZMQNotificationInterface::CreateWithArguments(mapArgs);

    if (pzmqNotificationInterface) {
        ValidationNotifier().addListener(pzmqNotificationInterface);
    }
#endif
    if (mapArgs.count("-maxuploadtarget")) {
        CNode::SetMaxOutboundTarget(GetArg("-maxuploadtarget", Settings::DefaultMaxUploadTarget)*1024*1024);
    }


    // ********************************************************* Step 7: import blocks

    if (mapArgs.count("-blocknotify"))
        uiInterface.NotifyBlockTip.connect(BlockNotifyCallback);

    Blocks::DB::startBlockImporter();
    if (chainActive.Tip() == nullptr) {
        logDebug(Log::Bitcoin) << "Waiting for genesis block to be imported...";
        while (!fRequestShutdown && chainActive.Tip() == nullptr)
            MilliSleep(10);
    }
    Application::instance()->validation()->start();

    // ********************************************************* Step 8: start node

    if (!CheckDiskSpace())
        return false;

    if (!strErrors.str().empty())
        return InitError(strErrors.str());

    RandAddSeedPerfmon();

    //// debug print
    logDebug(Log::DB) << "mapBlockIndex.size() =" << Blocks::Index::size();
    logDebug(Log::BlockValidation) << "nBestHeight =" << chainActive.Height();

    if (GetBoolArg("-listenonion", Settings::DefaultListenOnion))
        StartTorControl(threadGroup, scheduler);

    StartNode(threadGroup, scheduler);

    // Monitor the chain, and alert if we get blocks much quicker or slower than expected
    const int64_t nPowTargetSpacing = Params().GetConsensus().nPowTargetSpacing;
    scheduler.scheduleEvery(std::bind(&Blocks::DB::partitionCheck, Blocks::DB::instance(), nPowTargetSpacing), nPowTargetSpacing);

    // Generate coins in the background
    try {
        Mining::GenerateBitcoins(GetBoolArg("-gen", Settings::DefaultGenerateCoins), GetArg("-genproclimit", Settings::DefaultGenerateThreads),
                                 chainparams, GetArg("-gencoinbase", ""));
    } catch (const std::exception &e) {
        logCritical(Log::Bitcoin) << "Mining could not be activated. Reason:" << e;
    }

    // ********************************************************* Step 9: finished

    SetRPCWarmupFinished();
    uiInterface.InitMessage(_("Done loading"));

    return !fRequestShutdown;
}