miner.cpp

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Copyright (c) 2014-2015 The Dash developers
// Copyright (c) 2015-2018 The PIVX developers
// Copyright (c) 2018-2020 The DAPS Project developers
// Copyright (c) 2020-2022 The PRivaCY Coin Developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 
#include "miner.h"
 
#include "amount.h"
#include "blocksignature.h"
#include "consensus/merkle.h"
#include "consensus/tx_verify.h"
#include "hash.h"
#include "invalid.h"
#include "main.h"
#include "masternode-sync.h"
#include "net.h"
#include "poa.h"
#include "primitives/block.h"
#include "primitives/transaction.h"
#include "timedata.h"
#include "util.h"
#include "utilmoneystr.h"
#ifdef ENABLE_WALLET
#include "wallet/wallet.h"
extern CWallet* pwalletMain;
#endif
#include "masternode-payments.h"
#include "validationinterface.h"
 
#include <boost/thread.hpp>
#include <boost/tuple/tuple.hpp>
 
 
//
// PRCYcoinMiner
//
 
//
// Unconfirmed transactions in the memory pool often depend on other
// transactions in the memory pool. When we select transactions from the
// pool, we select by highest priority or fee rate, so we might consider
// transactions that depend on transactions that aren't yet in the block.
// The COrphan class keeps track of these 'temporary orphans' while
// CreateBlock is figuring out which transactions to include.
//
class COrphan
{
public:
    const CTransaction* ptx;
    std::set<uint256> setDependsOn;
    CFeeRate feeRate;
    double dPriority;
 
    COrphan(const CTransaction* ptxIn) : ptx(ptxIn), feeRate(0), dPriority(0)
    {
    }
};
 
uint64_t nLastBlockTx = 0;
uint64_t nLastBlockSize = 0;
int64_t nLastCoinStakeSearchInterval = 0;
int64_t nDefaultMinerSleep = 0;
//int64_t nConsolidationTime = 0;
 
// We want to sort transactions by priority and fee rate, so:
typedef boost::tuple<double, CFeeRate, const CTransaction*> TxPriority;
class TxPriorityCompare
{
    bool byFee;
 
public:
    TxPriorityCompare(bool _byFee) : byFee(_byFee) {}
 
    bool operator()(const TxPriority& a, const TxPriority& b)
    {
        if (byFee) {
            if (a.get<1>() == b.get<1>())
                return a.get<0>() < b.get<0>();
            return a.get<1>() < b.get<1>();
        } else {
            if (a.get<0>() == b.get<0>())
                return a.get<1>() < b.get<1>();
            return a.get<0>() < b.get<0>();
        }
    }
};
 
void UpdateTime(CBlockHeader* pblock, const CBlockIndex* pindexPrev)
{
    pblock->nTime = std::max(pindexPrev->GetMedianTimePast() + 1, GetAdjustedTime());
 
    // Updating time can change work required on testnet:
    if (Params().AllowMinDifficultyBlocks())
        pblock->nBits = GetNextWorkRequired(pindexPrev, pblock);
}
 
uint32_t GetListOfPoSInfo(uint32_t currentHeight, std::vector<PoSBlockSummary>& audits)
{
    //A PoA block should be mined only after at least 59 PoS blocks have not been audited
    //Look for the previous PoA block
    uint32_t nloopIdx = currentHeight;
    while (nloopIdx >= Params().START_POA_BLOCK()) {
        if (chainActive[nloopIdx]->GetBlockHeader().IsPoABlockByVersion()) {
            break;
        }
        nloopIdx--;
    }
    if (nloopIdx <= Params().START_POA_BLOCK()) {
        //this is the first PoA block ==> take all PoS blocks from LAST_POW_BLOCK up to currentHeight - 60 inclusive
        for (int i = Params().LAST_POW_BLOCK() + 1; i <= Params().LAST_POW_BLOCK() + (size_t)Params().MAX_NUM_POS_BLOCKS_AUDITED(); i++) {
            PoSBlockSummary pos;
            pos.hash = chainActive[i]->GetBlockHash();
            CBlockIndex* pindex = mapBlockIndex[pos.hash];
            pos.nTime = ReVerifyPoSBlock(pindex) ? chainActive[i]->GetBlockHeader().nTime : 0;
            pos.height = i;
            audits.push_back(pos);
        }
    } else {
        //Find the previous PoA block
        uint32_t start = nloopIdx;
        if (start > Params().START_POA_BLOCK()) {
            CBlockIndex* pblockindex = chainActive[start];
            CBlock block;
            if (!ReadBlockFromDisk(block, pblockindex))
                throw std::runtime_error("Can't read block from disk");
            PoSBlockSummary back = block.posBlocksAudited.back();
            uint32_t lastAuditedHeight = back.height;
            uint32_t nextAuditHeight = lastAuditedHeight + 1;
 
            while (nextAuditHeight <= currentHeight) {
                CBlockIndex* posIndex = chainActive[nextAuditHeight];
                CBlock posBlock;
                if (!ReadBlockFromDisk(posBlock, posIndex))
                    throw std::runtime_error("Can't read block from disk");
                if (posBlock.IsProofOfStake()) {
                    PoSBlockSummary pos;
                    pos.hash = chainActive[nextAuditHeight]->GetBlockHash();
                    CBlockIndex* pindex = mapBlockIndex[pos.hash];
                    pos.nTime = ReVerifyPoSBlock(pindex) ? chainActive[nextAuditHeight]->GetBlockHeader().nTime : 0;
                    pos.height = nextAuditHeight;
                    audits.push_back(pos);
                }
                //The current number of PoS blocks audited in a PoA block is changed from 59 to MAX
                if (audits.size() == (size_t)Params().MAX_NUM_POS_BLOCKS_AUDITED()) {
                    break;
                }
                nextAuditHeight++;
            }
        }
    }
    return nloopIdx;
}
 
CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn, const CPubKey& txPub, const CKey& txPriv, CWallet* pwallet, bool fProofOfStake)
{
    CReserveKey reservekey(pwallet);
 
    // Create new block
    std::unique_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
    if (!pblocktemplate.get())
        return NULL;
 
    CBlock* pblock = &pblocktemplate->block; // pointer for convenience
 
    // Tip
    CBlockIndex* pindexPrev = nullptr;
    {   // Don't keep cs_main locked
        LOCK(cs_main);
        pindexPrev = chainActive.Tip();
    }
 
    const int nHeight = pindexPrev->nHeight + 1;
 
    pblock->nVersion = 5;   // Supports CLTV activation
 
    // -regtest only: allow overriding block.nVersion with
    // -blockversion=N to test forking scenarios
    if (Params().MineBlocksOnDemand())
        pblock->nVersion = GetArg("-blockversion", pblock->nVersion);
 
    // Create coinbase tx
    CMutableTransaction txNew;
    txNew.vin.resize(1);
    txNew.vin[0].prevout.SetNull();
    txNew.vout.resize(1);
    txNew.vout[0].scriptPubKey = scriptPubKeyIn;
    std::copy(txPub.begin(), txPub.end(), std::back_inserter(txNew.vout[0].txPub));
    std::copy(txPriv.begin(), txPriv.end(), std::back_inserter(txNew.vout[0].txPriv));
 
    CBlockIndex* prev = chainActive.Tip();
    CAmount nValue = GetBlockValue(prev->nHeight);
    txNew.vout[0].nValue = nValue;
 
    pblock->vtx.push_back(txNew);
    pblocktemplate->vTxFees.push_back(-1);   // updated at end
    pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 
    // ppcoin: if coinstake available add coinstake tx
    static int64_t nLastCoinStakeSearchTime = GetAdjustedTime(); // only initialized at startup
 
    if (fProofOfStake) {
        boost::this_thread::interruption_point();
        pblock->nTime = GetAdjustedTime();
        pblock->nBits = GetNextWorkRequired(pindexPrev, pblock);
 
        int64_t nSearchTime = pblock->nTime; // search to current time
        bool fStakeFound = false;
        if (nSearchTime >= nLastCoinStakeSearchTime) {
            unsigned int nTxNewTime = 0;
            CMutableTransaction txCoinStake;
            if (pwallet->CreateCoinStake(*pwallet, pblock->nBits, nSearchTime - nLastCoinStakeSearchTime, txCoinStake, nTxNewTime)) {
                pblock->nTime = nTxNewTime;
                pblock->vtx[0].vout[0].SetEmpty();
                CTransaction copied(txCoinStake);
                pblock->vtx.push_back(copied);
                fStakeFound = true;
            }
 
            nLastCoinStakeSearchInterval = nSearchTime - nLastCoinStakeSearchTime;
            nLastCoinStakeSearchTime = nSearchTime;
        }
 
        if (!fStakeFound) {
            LogPrint(BCLog::STAKING, "CreateNewBlock(): stake not found\n");
            return NULL;
        }
    }
 
    // Largest block you're willing to create:
    unsigned int nBlockMaxSize = GetArg("-blockmaxsize", DEFAULT_BLOCK_MAX_SIZE);
    // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
    unsigned int nBlockMaxSizeNetwork = MAX_BLOCK_SIZE_CURRENT;
    nBlockMaxSize = std::max((unsigned int)1000, std::min((nBlockMaxSizeNetwork - 1000), nBlockMaxSize));
 
    // How much of the block should be dedicated to high-priority transactions,
    // included regardless of the fees they pay
    unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", DEFAULT_BLOCK_PRIORITY_SIZE);
    nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
 
    // Minimum block size you want to create; block will be filled with free transactions
    // until there are no more or the block reaches this size:
    unsigned int nBlockMinSize = GetArg("-blockminsize", DEFAULT_BLOCK_MIN_SIZE);
    nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
 
    // Collect memory pool transactions into the block
    CAmount nFees = 0;
 
    {
        LOCK2(cs_main, mempool.cs);
 
        CBlockIndex* pindexPrev = chainActive.Tip();
        const int nHeight = pindexPrev->nHeight + 1;
        CCoinsViewCache view(pcoinsTip);
 
        // Priority order to process transactions
        std::list<COrphan> vOrphan; // list memory doesn't move
        std::map<uint256, std::vector<COrphan*> > mapDependers;
        bool fPrintPriority = GetBoolArg("-printpriority", false);
 
        // This vector will be sorted into a priority queue:
        std::vector<TxPriority> vecPriority;
        vecPriority.reserve(mempool.mapTx.size());
        std::set<CKeyImage> keyImages;
        for (std::map<uint256, CTxMemPoolEntry>::iterator mi = mempool.mapTx.begin();
             mi != mempool.mapTx.end(); ++mi) {
            const CTransaction& tx = mi->second.GetTx();
            if (tx.IsCoinBase() || tx.IsCoinStake() || !IsFinalTx(tx, nHeight)) {
                continue;
            }
            bool fKeyImageCheck = true;
            // Check key images not duplicated with what in db
            for (const CTxIn& txin : tx.vin) {
                const CKeyImage& keyImage = txin.keyImage;
                if (IsSpentKeyImage(keyImage.GetHex(), UINT256_ZERO)) {
                    fKeyImageCheck = false;
                    break;
                }
                //Check for invalid/fraudulent inputs. They shouldn't make it through mempool, but check anyways.
                if (invalid_out::ContainsOutPoint(txin.prevout)) {
                    LogPrintf("%s : found invalid input %s in tx %s", __func__, txin.prevout.ToString(), tx.GetHash().ToString());
                    break;
                }
            }
 
            if (!fKeyImageCheck) {
                continue;
            }
 
            if (!CheckHaveInputs(view, tx)) continue;
 
            COrphan* porphan = NULL;
            double dPriority = 0;
            CAmount nTotalIn = 0;
 
            // Priority is sum(valuein * age) / modified_txsize
            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
            dPriority = GetPriority(tx, chainActive.Height());
 
            uint256 hash = tx.GetHash();
            mempool.ApplyDeltas(hash, dPriority, nTotalIn);
 
            CFeeRate feeRate(tx.nTxFee, nTxSize);
 
            bool isDuplicate = false;
            for (const CTxIn& txin : tx.vin) {
                const CKeyImage& keyImage = txin.keyImage;
                if (keyImages.count(keyImage)) {
                    isDuplicate = true;
                    break;
                }
                keyImages.insert(keyImage);
            }
            if (isDuplicate) continue;
            vecPriority.push_back(TxPriority(dPriority, feeRate, &mi->second.GetTx()));
        }
 
        LogPrint(BCLog::STAKING, "Selecting %d transactions from mempool\n", vecPriority.size());
        // Collect transactions into block
        uint64_t nBlockSize = 1000;
        uint64_t nBlockTx = 0;
        int nBlockSigOps = 100;
        bool fSortedByFee = (nBlockPrioritySize <= 0);
 
        TxPriorityCompare comparer(fSortedByFee);
        std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 
        std::vector<CBigNum> vBlockSerials;
        std::vector<CBigNum> vTxSerials;
        while (!vecPriority.empty()) {
            // Take highest priority transaction off the priority queue:
            double dPriority = vecPriority.front().get<0>();
            CFeeRate feeRate = vecPriority.front().get<1>();
            const CTransaction& tx = *(vecPriority.front().get<2>());
 
            std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
            vecPriority.pop_back();
 
            // Size limits
            unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
            if (nBlockSize + nTxSize >= nBlockMaxSize)
                continue;
 
            // Skip free transactions if we're past the minimum block size:
            const uint256& hash = tx.GetHash();
            double dPriorityDelta = 0;
            CAmount nFeeDelta = 0;
            mempool.ApplyDeltas(hash, dPriorityDelta, nFeeDelta);
            CFeeRate customMinRelayTxFee = CFeeRate(5000);
            if (fSortedByFee && (feeRate < customMinRelayTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
                continue;
 
            // Prioritise by fee once past the priority size or we run out of high-priority
            // transactions:
            if (!fSortedByFee &&
                ((nBlockSize + nTxSize >= nBlockPrioritySize) || !AllowFree(dPriority))) {
                fSortedByFee = true;
                comparer = TxPriorityCompare(fSortedByFee);
                std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
            }
 
            if (!CheckHaveInputs(view, tx))
                continue;
 
            CAmount nTxFees = tx.nTxFee;
 
            // Note that flags: we don't want to set mempool/IsStandard()
            // policy here, but we still have to ensure that the block we
            // create only contains transactions that are valid in new blocks.
 
            CValidationState state;
            if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true))
                continue;
 
            CTxUndo txundo;
            if (tx.IsCoinStake()) {
                UpdateCoins(tx, view, txundo, nHeight);
            }
 
            // Added
            pblock->vtx.push_back(tx);
            pblocktemplate->vTxFees.push_back(nTxFees);
            pblocktemplate->vTxSigOps.push_back(0);
            nBlockSize += nTxSize;
            ++nBlockTx;
            nFees += nTxFees;
 
            for (const CBigNum& bnSerial : vTxSerials)
                vBlockSerials.emplace_back(bnSerial);
 
            if (fPrintPriority) {
                LogPrintf("priority %.1f fee %s txid %s\n",
                    dPriority, feeRate.ToString(), tx.GetHash().ToString());
            }
 
            // Add transactions that depend on this one to the priority queue
            if (mapDependers.count(hash)) {
                for (COrphan* porphan : mapDependers[hash]) {
                    if (!porphan->setDependsOn.empty()) {
                        porphan->setDependsOn.erase(hash);
                        if (porphan->setDependsOn.empty()) {
                            vecPriority.push_back(TxPriority(porphan->dPriority, porphan->feeRate, porphan->ptx));
                            std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
                        }
                    }
                }
            }
        }
 
        if (!fProofOfStake) {
            //Masternode and general budget payments
            FillBlockPayee(txNew, nFees, fProofOfStake);
 
            //Make payee
            if (txNew.vout.size() > 1) {
                pblock->payee = txNew.vout[1].scriptPubKey;
            } else {
                CAmount blockValue = nFees + GetBlockValue(pindexPrev->nHeight);
                txNew.vout[0].nValue = blockValue;
                txNew.vin[0].scriptSig = CScript() << nHeight << OP_0;
            }
        }
 
        nLastBlockTx = nBlockTx;
        nLastBlockSize = nBlockSize;
 
        // Compute final coinbase transaction.
        pblock->vtx[0].vin[0].scriptSig = CScript() << nHeight << OP_0;
        pblock->vtx[0].txType = TX_TYPE_REVEAL_AMOUNT;
        if (!fProofOfStake) {
            pblock->vtx[0].vout[0].nValue += nFees;
            pblocktemplate->vTxFees[0] = nFees;
        } else {
            pblock->vtx[1].vout[2].nValue += nFees;
            pblocktemplate->vTxFees[0] = nFees;
        }
 
        CPubKey sharedSec;
        sharedSec.Set(txPub.begin(), txPub.end());
        //compute commitment
        unsigned char zeroBlind[32];
        memset(zeroBlind, 0, 32);
        if (pblock->IsProofOfWork()) {
            pwallet->EncodeTxOutAmount(pblock->vtx[0].vout[0], pblock->vtx[0].vout[0].nValue, sharedSec.begin());
            nValue = pblock->vtx[0].vout[0].nValue;
            if (!pwallet->CreateCommitment(zeroBlind, nValue, pblock->vtx[0].vout[0].commitment)) {
                return NULL;
            }
        } else {
            pblock->vtx[1].vout[1].nValue += pblock->vtx[1].vout[2].nValue;
            pblock->vtx[1].vout[2].SetEmpty();
            sharedSec.Set(pblock->vtx[1].vout[1].txPub.begin(), pblock->vtx[1].vout[1].txPub.end());
            pwallet->EncodeTxOutAmount(pblock->vtx[1].vout[1], pblock->vtx[1].vout[1].nValue, sharedSec.begin());
            nValue = pblock->vtx[1].vout[1].nValue;
            pblock->vtx[1].vout[1].commitment.clear();
            if (!pwallet->CreateCommitment(zeroBlind, nValue, pblock->vtx[1].vout[1].commitment)) {
                return NULL;
            }
 
            //Shnorr sign
            if (!pwalletMain->MakeShnorrSignature(pblock->vtx[1])) {
                LogPrintf("%s : failed to make Shnorr signature\n", __func__);
                return NULL;
            }
 
            //Test verify shnorr signature
            if (!VerifyShnorrKeyImageTx(pblock->vtx[1])) {
                LogPrintf("%s: Failed to verify shnorr key image\n", __func__);
                return NULL;
            }
            pwalletMain->IsTransactionForMe(pblock->vtx[1]);
        }
 
        // Fill in header
        pblock->hashPrevBlock = pindexPrev->GetBlockHash();
        if (!fProofOfStake)
            UpdateTime(pblock, pindexPrev);
        pblock->nBits = GetNextWorkRequired(pindexPrev, pblock);
        pblock->nNonce = 0;
        uint256 nCheckpoint = 0;
        pblock->nAccumulatorCheckpoint = nCheckpoint;
        pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 
        if (fProofOfStake) {
            unsigned int nExtraNonce = 0;
            IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
            LogPrintf("CPUMiner : proof-of-stake block found %s \n", pblock->GetHash().ToString().c_str());
            if (!SignBlock(*pblock, *pwallet)) {
                LogPrintf("%s: Signing new block failed, computing private key \n", __func__);
                if (pblock->vtx.size() > 1 && pblock->vtx[1].vout.size() > 1) {
                    pwallet->AddComputedPrivateKey(pblock->vtx[1].vout[1]);
                }
                if (!SignBlock(*pblock, *pwallet)) {
                    LogPrintf("%s: Signing new block with UTXO key failed \n", __func__);
                    return NULL;
                }
            }
        }
    }
 
    return pblocktemplate.release();
}
 
CBlockTemplate* CreateNewPoABlock(const CScript& scriptPubKeyIn, const CPubKey& txPub, const CKey& txPriv, CWallet* pwallet)
{
    CReserveKey reservekey(pwallet);
 
    if (chainActive.Tip()->nHeight < Params().START_POA_BLOCK()) {
        return NULL;
    }
 
    // Create new block
    std::unique_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
    if (!pblocktemplate.get())
        return NULL;
    CBlock* pblock = &pblocktemplate->block; // pointer for convenience
 
    pblock->SetNull();
    // Create coinbase tx
    CMutableTransaction txNew;
    txNew.vin.resize(1);
    txNew.vin[0].prevout.SetNull();
    txNew.vout.resize(1);
    //Value of this vout coinbase will be computed based on the number of audited PoS blocks
    //This will be computed later
    txNew.vout[0].scriptPubKey = scriptPubKeyIn;
    std::copy(txPub.begin(), txPub.end(), std::back_inserter(txNew.vout[0].txPub));
    std::copy(txPriv.begin(), txPriv.end(), std::back_inserter(txNew.vout[0].txPriv));
 
    pblock->vtx.push_back(txNew);
    pblocktemplate->vTxFees.push_back(-1);   // updated at end
    pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 
    boost::this_thread::interruption_point();
    pblock->nTime = GetAdjustedTime();
    CBlockIndex* pindexPrev = chainActive.Tip();
    pblock->nBits = GetNextWorkRequired(pindexPrev, pblock);
 
    int nprevPoAHeight;
 
    nprevPoAHeight = GetListOfPoSInfo(pindexPrev->nHeight, pblock->posBlocksAudited);
 
    if (pblock->posBlocksAudited.size() == 0) {
        return NULL;
    }
 
    // Set block version to differentiate PoA blocks from PoS blocks
    pblock->SetVersionPoABlock();
    pblock->nTime = GetAdjustedTime();
 
    //compute PoA block reward
    CAmount nReward;
    if (pindexPrev->nHeight >= Params().HardFork()) {
        nReward = pblock->posBlocksAudited.size() * 0.25 * COIN;
    } else {
        nReward = pblock->posBlocksAudited.size() * 0.5 * COIN;
    }
    pblock->vtx[0].vout[0].nValue = nReward;
    pblock->vtx[0].txType = TX_TYPE_REVEAL_AMOUNT;
 
    CPubKey sharedSec;
    sharedSec.Set(txPub.begin(), txPub.end());
    unsigned char zeroBlind[32];
    memset(zeroBlind, 0, 32);
    pwallet->EncodeTxOutAmount(pblock->vtx[0].vout[0], pblock->vtx[0].vout[0].nValue, sharedSec.begin());
    if (!pwallet->CreateCommitment(zeroBlind, pblock->vtx[0].vout[0].nValue, pblock->vtx[0].vout[0].commitment)) {
        LogPrintf("%s: unable to create commitment to 0\n", __func__);
        return NULL;
    }
    pwallet->EncodeTxOutAmount(pblock->vtx[0].vout[0], pblock->vtx[0].vout[0].nValue, sharedSec.begin());
 
    //Comment out all previous code, because a PoA block does not verify any transaction, except reward transactions to miners
    // No need to collect memory pool transactions into the block
    const int nHeight = pindexPrev->nHeight + 1;
 
    // Fill in header
    pblock->hashPrevBlock = pindexPrev->GetBlockHash();
    if (nprevPoAHeight >= Params().START_POA_BLOCK()) {
        pblock->hashPrevPoABlock = *(chainActive[nprevPoAHeight]->phashBlock);
    } else {
        pblock->hashPrevPoABlock.SetNull();
    }
 
    //ATTENTION: This is used for setting always the easiest difficulty for PoA miners
    pblock->nBits = GetNextWorkRequired(pindexPrev, pblock);
    pblock->nNonce = 0;
 
    pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 
    // Compute final coinbase transaction.
    CMutableTransaction txCoinbase(pblock->vtx[0]);
    txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(1)) + COINBASE_FLAGS;
    assert(txCoinbase.vin[0].scriptSig.size() <= 100);
 
    pblock->vtx[0] = txCoinbase;
    pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
 
    pblock->hashPoAMerkleRoot = pblock->ComputePoAMerkleTree();
    pblock->minedHash = pblock->ComputeMinedHash();
 
    return pblocktemplate.release();
}
 
void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
{
    // Update nExtraNonce
    static uint256 hashPrevBlock;
    if (hashPrevBlock != pblock->hashPrevBlock) {
        nExtraNonce = 0;
        hashPrevBlock = pblock->hashPrevBlock;
    }
    ++nExtraNonce;
    unsigned int nHeight = pindexPrev->nHeight + 1; // Height first in coinbase required for block.version=2
    CMutableTransaction txCoinbase(pblock->vtx[0]);
    txCoinbase.vin[0].scriptSig = (CScript() << nHeight << CScriptNum(nExtraNonce)) + COINBASE_FLAGS;
    assert(txCoinbase.vin[0].scriptSig.size() <= 100);
 
    pblock->vtx[0] = txCoinbase;
    pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
}
 
#ifdef ENABLE_WALLET
//
// Internal miner
//
double dHashesPerSec = 0.0;
int64_t nHPSTimerStart = 0;
 
CBlockTemplate* CreateNewBlockWithKey(CReserveKey& reservekey, CWallet* pwallet, bool fProofOfStake)
{
    CPubKey pubkey, txPub;
    CKey priv;
    if (!pwallet->GenerateAddress(pubkey, txPub, priv))
        return nullptr;
 
    const int nHeightNext = chainActive.Tip()->nHeight + 1;
    static int nLastPOWBlock = Params().LAST_POW_BLOCK();
 
    // If we're building a late PoW block, don't continue
    if ((nHeightNext > nLastPOWBlock) && !fProofOfStake) {
        LogPrintf("%s: Aborting PoW block creation during PoS phase\n", __func__);
        // sleep 1/2 a block time so we don't go into a tight loop.
        MilliSleep((Params().TargetSpacing() * 1000) >> 1);
        return nullptr;
    }
 
    CScript scriptPubKey = CScript() << ToByteVector(pubkey) << OP_CHECKSIG;
    return CreateNewBlock(scriptPubKey, txPub, priv, pwallet, fProofOfStake);
}
 
CBlockTemplate* CreateNewPoABlockWithKey(CReserveKey& reservekey, CWallet* pwallet)
{
    CPubKey pubkey, txPub;
    CKey txPriv;
    if (!pwallet->GenerateAddress(pubkey, txPub, txPriv))
        return NULL;
 
    CScript scriptPubKey = CScript() << ToByteVector(pubkey) << OP_CHECKSIG;
    return CreateNewPoABlock(scriptPubKey, txPub, txPriv, pwallet);
}
 
bool ProcessBlockFound(CBlock* pblock, CWallet& wallet, CReserveKey& reservekey)
{
    LogPrintf("%s\n", pblock->ToString());
 
    // Found a solution
    {
        WAIT_LOCK(g_best_block_mutex, lock);
        if (pblock->hashPrevBlock != g_best_block)
            return error("PRCYcoinMiner : generated block is stale");
    }
 
    // Remove key from key pool
    reservekey.KeepKey();
 
    // Track how many getdata requests this block gets
    {
        LOCK(wallet.cs_wallet);
        wallet.mapRequestCount[pblock->GetHash()] = 0;
    }
 
    // Inform about the new block
    GetMainSignals().BlockFound(pblock->GetHash());
 
    // Process this block the same as if we had received it from another node
    CValidationState state;
    if (!ProcessNewBlock(state, NULL, pblock))
        return error("PRCYcoinMiner : ProcessNewBlock, block not accepted");
 
    for (CNode* node : vNodes) {
        node->PushInventory(CInv(MSG_BLOCK, pblock->GetHash()));
    }
 
    return true;
}
 
bool fGeneratePrcycoins = false;
bool fMintableCoins = false;
int nMintableLastCheck = 0;
 
// ***TODO*** that part changed in bitcoin, we are using a mix with old one here for now
 
void BitcoinMiner(CWallet* pwallet, bool fProofOfStake)
{
    LogPrintf("PRCYcoinMiner started\n");
    SetThreadPriority(THREAD_PRIORITY_LOWEST);
    util::ThreadRename("prcycoin-miner");
    fGeneratePrcycoins = true;
    // Each thread has its own key and counter
    CReserveKey reservekey(pwallet);
    unsigned int nExtraNonce = 0;
    bool fLastLoopOrphan = false;
    while (fGeneratePrcycoins || fProofOfStake) {
        if (chainActive.Tip()->nHeight >= Params().LAST_POW_BLOCK()) fProofOfStake = true;
        if (fProofOfStake) {
            //control the amount of times the client will check for mintable coins
            if ((GetTime() - nMintableLastCheck > 5 * 60)) // 5 minute check time
            {
                nMintableLastCheck = GetTime();
                fMintableCoins = pwallet->MintableCoins();
            }
 
            while (vNodes.empty() || pwallet->IsLocked() || !fMintableCoins ||
                   nReserveBalance >= pwallet->GetBalance() || !masternodeSync.IsSynced()) {
                nLastCoinStakeSearchInterval = 0;
                MilliSleep(5000);
                // Do a separate 1 minute check here to ensure fMintableCoins is updated
                if (!fMintableCoins && (GetTime() - nMintableLastCheck > 1 * 60)) // 1 minute check time
                {
                    nMintableLastCheck = GetTime();
                    fMintableCoins = pwallet->MintableCoins();
                }
                if (!fGeneratePrcycoins) {
                    break;
                }
            }
 
            if (!fGeneratePrcycoins) {
                LogPrintf("Stopping staking or mining\n");
                nLastCoinStakeSearchInterval = 0;
                break;
            }
 
            //search our map of hashed blocks, see if bestblock has been hashed yet
            if (mapHashedBlocks.count(chainActive.Tip()->nHeight) && !fLastLoopOrphan)
            {
                // wait half of the nHashDrift with max wait of 3 minutes
                if (GetTime() - mapHashedBlocks[chainActive.Tip()->nHeight] < std::max(pwallet->nHashInterval, (unsigned int)1))
                {
                    MilliSleep(5000);
                    continue;
                }
            }
        } else { // PoW
            if ((chainActive.Tip()->nHeight - 6) > Params().LAST_POW_BLOCK())
            {
                // Run for a little while longer, just in case there is a rewind on the chain.
                LogPrintf("%s: Exiting Proof of Work Mining Thread at height: %d\n",
                          __func__, chainActive.Tip()->nHeight);
                return;
            }
       }
 
        //
        // Create new block
        //
        unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
        CBlockIndex* pindexPrev;
        {
            LOCK(cs_main);
            pindexPrev = chainActive.Tip();
        }
        if (!pindexPrev)
            continue;
 
        std::unique_ptr<CBlockTemplate> pblocktemplate(CreateNewBlockWithKey(reservekey, pwallet, fProofOfStake));
        if (!pblocktemplate.get())
            continue;
 
        CBlock* pblock = &pblocktemplate->block;
        IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
 
        //Stake miner main
        if (fProofOfStake) {
            LogPrintf("CPUMiner : proof-of-stake block found %s \n", pblock->GetHash().ToString().c_str());
            if (!SignBlock(*pblock, *pwallet)) {
                LogPrintf("%s: Signing new block failed, computing private key \n", __func__);
                if (pblock->vtx.size() > 1 && pblock->vtx[1].vout.size() > 1) {
                    pwallet->AddComputedPrivateKey(pblock->vtx[1].vout[1]);
                }
                if (!SignBlock(*pblock, *pwallet)) {
                    LogPrintf("%s: Signing new block with UTXO key failed \n", __func__);
                    continue;
                }
            }
 
            LogPrintf("CPUMiner : proof-of-stake block was signed %s \n", pblock->GetHash().ToString().c_str());
            SetThreadPriority(THREAD_PRIORITY_NORMAL);
            if (!ProcessBlockFound(pblock, *pwallet, reservekey)) {
                continue;
            }
            SetThreadPriority(THREAD_PRIORITY_LOWEST);
 
            continue;
        }
 
        LogPrint(BCLog::STAKING, "Running PRCYcoinMiner with %u transactions in block (%u bytes)\n", pblock->vtx.size(),
            ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
 
        //
        // Search
        //
        int64_t nStart = GetTime();
        uint256 hashTarget = uint256().SetCompact(pblock->nBits);
        while (true) {
            unsigned int nHashesDone = 0;
 
            uint256 hash;
            while (true) {
                hash = pblock->GetHash();
                if (hash <= hashTarget) {
                    // Found a solution
                    SetThreadPriority(THREAD_PRIORITY_NORMAL);
                    ProcessBlockFound(pblock, *pwallet, reservekey);
                    if (!ProcessBlockFound(pblock, *pwallet, reservekey)) {
                        fLastLoopOrphan = true;
                        continue;
                    }
                    SetThreadPriority(THREAD_PRIORITY_LOWEST);
 
                    // In regression test mode, stop mining after a block is found. This
                    // allows developers to controllably generate a block on demand.
                    if (Params().MineBlocksOnDemand()) {
                        throw boost::thread_interrupted();
                    }
 
                    break;
                }
                pblock->nNonce += 1;
                nHashesDone += 1;
                if ((pblock->nNonce & 0xFF) == 0)
                    break;
            }
 
            // Meter hashes/sec
            static int64_t nHashCounter;
            if (nHPSTimerStart == 0) {
                nHPSTimerStart = GetTimeMillis();
                nHashCounter = 0;
            } else
                nHashCounter += nHashesDone;
            if (GetTimeMillis() - nHPSTimerStart > 4000) {
                static RecursiveMutex cs;
                {
                    LOCK(cs);
                    if (GetTimeMillis() - nHPSTimerStart > 4000) {
                        dHashesPerSec = 1000.0 * nHashCounter / (GetTimeMillis() - nHPSTimerStart);
                        nHPSTimerStart = GetTimeMillis();
                        nHashCounter = 0;
                        static int64_t nLogTime;
                        if (GetTime() - nLogTime > 30 * 60) {
                            nLogTime = GetTime();
                            LogPrintf("hashmeter %6.0f khash/s\n", dHashesPerSec / 1000.0);
                        }
                    }
                }
            }
 
            // Check for stop or if block needs to be rebuilt
            boost::this_thread::interruption_point();
            // Regtest mode doesn't require peers
            if (vNodes.empty() && Params().MiningRequiresPeers())
                break;
            if (pblock->nNonce >= 0xffff0000)
                break;
            if (mempool.GetTransactionsUpdated() != nTransactionsUpdatedLast && GetTime() - nStart > 60)
                break;
            if (pindexPrev != chainActive.Tip())
                break;
 
            // Update nTime every few seconds
            UpdateTime(pblock, pindexPrev);
            if (Params().AllowMinDifficultyBlocks()) {
                // Changing pblock->nTime can change work required on testnet:
                hashTarget.SetCompact(pblock->nBits);
            }
        }
    }
}
 
void static ThreadBitcoinMiner(void* parg)
{
    boost::this_thread::interruption_point();
    CWallet* pwallet = (CWallet*)parg;
    try {
        if (chainActive.Tip()->nHeight >= Params().LAST_POW_BLOCK()) {
            BitcoinMiner(pwallet, true);
        } else {
            BitcoinMiner(pwallet, false);
        }
        boost::this_thread::interruption_point();
    } catch (const std::exception& e) {
        LogPrintf("PRCYcoinMiner exception\n");
    } catch (...) {
        LogPrintf("PRCYcoinMiner exception\n");
    }
 
    LogPrintf("PRCYcoinMiner exiting\n");
}
 
void static ThreadPrcycoinMiner(void* parg)
{
    boost::this_thread::interruption_point();
    try {
        //create a PoA after every 3 minute if enough PoS blocks created
        while (true) {
            boost::this_thread::sleep_for(boost::chrono::milliseconds(180 * 1000));
            //TODO: call CreateNewPoABlock function to create PoA blocks
        }
        boost::this_thread::interruption_point();
    } catch (const std::exception& e) {
        LogPrintf("ThreadBitcoinMiner() exception: %s \n", e.what());
    } catch (...) {
        LogPrintf("ThreadBitcoinMiner() error \n");
    }
 
    LogPrintf("ThreadBitcoinMiner exiting\n");
}
 
void GeneratePoAPrcycoin(CWallet* pwallet, int period)
{
    static boost::thread_group* minerThreads = NULL;
 
    if (minerThreads != NULL) {
        minerThreads->interrupt_all();
        delete minerThreads;
        minerThreads = NULL;
    }
 
    minerThreads = new boost::thread_group();
    minerThreads->create_thread(boost::bind(&ThreadPrcycoinMiner, pwallet));
}
 
void GeneratePrcycoins(bool fGenerate, CWallet* pwallet, int nThreads)
{
    static boost::thread_group* minerThreads = NULL;
    fGeneratePrcycoins = fGenerate;
 
    if (nThreads < 0) {
        // In regtest threads defaults to 1
        if (Params().DefaultMinerThreads())
            nThreads = Params().DefaultMinerThreads();
        else
            nThreads = boost::thread::hardware_concurrency();
    }
 
    if (minerThreads != NULL) {
        minerThreads->interrupt_all();
        delete minerThreads;
        minerThreads = NULL;
    }
 
    if (nThreads == 0 || !fGenerate)
        return;
 
    minerThreads = new boost::thread_group();
    for (int i = 0; i < nThreads; i++)
        minerThreads->create_thread(boost::bind(&ThreadBitcoinMiner, pwallet));
}
 
// ppcoin: stake minter thread
void ThreadStakeMinter()
{
    boost::this_thread::interruption_point();
    LogPrintf("ThreadStakeMinter started\n");
    CWallet* pwallet = pwalletMain;
    try {
        BitcoinMiner(pwallet, true);
        boost::this_thread::interruption_point();
    } catch (const std::exception& e) {
        LogPrintf("ThreadStakeMinter() exception: %s \n", e.what());
    } catch (...) {
        LogPrintf("ThreadStakeMinter() error \n");
    }
    LogPrintf("ThreadStakeMinter exiting,\n");
}
 
#endif // ENABLE_WALLET