// Copyright (c) 2014-2015 The Dash developers
// Copyright (c) 2015-2019 The PIVX developers
// Copyright (c) 2022-2036 Agrarian Developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "masternode-payments.h"

#include "addrman.h"
#include "chainparams.h"
#include "masternode-budget.h"
#include "masternode-sync.h"
#include "masternodeman.h"
#include "obfuscation.h"
#include "spork.h"
#include "sync.h"
#include "util.h"
#include "utilmoneystr.h"

#include <boost/filesystem.hpp>

#include <algorithm>
#include <cstdio>
#include <limits>
#include <string>
#include <vector>

/** Object for who's going to get paid on which blocks */
CMasternodePayments masternodePayments;

CCriticalSection cs_vecPayments;
CCriticalSection cs_mapMasternodeBlocks;
CCriticalSection cs_mapMasternodePayeeVotes;

namespace {

// Select the correct "newly created" transaction for payee validation based on block type.
// - PoW blocks: coinbase is vtx[0]
// - PoS blocks: coinstake is vtx[1] (with a null coinbase at vtx[0])
//
// This must NOT be derived from height-era assumptions, because Agrarian runs PoW+PoS concurrently
// from Params().FIRST_POS_BLOCK() through Params().LAST_POW_BLOCK().
const CTransaction& GetBlockNewTxForPayeeChecks(const CBlock& block)
{
    // Defensive: preserve old behavior if vector is unexpectedly small.
    // A valid PoS block should have at least 2 tx; a valid PoW block at least 1 tx.
    if (block.IsProofOfStake() && block.vtx.size() > 1) {
        return block.vtx[1];
    }
    return block.vtx[0];
}

} // namespace

//
// CMasternodePaymentDB
//

CMasternodePaymentDB::CMasternodePaymentDB()
{
    pathDB = GetDataDir() / "mnpayments.dat";
    strMagicMessage = "MasternodePayments";
}

bool CMasternodePaymentDB::Write(const CMasternodePayments& objToSave)
{
    const int64_t nStart = GetTimeMillis();

    // serialize, checksum data up to that point, then append checksum
    CDataStream ssObj(SER_DISK, CLIENT_VERSION);
    ssObj << strMagicMessage;                   // masternode cache file specific magic message
    ssObj << FLATDATA(Params().MessageStart()); // network specific magic number
    ssObj << objToSave;
    const uint256 hash = Hash(ssObj.begin(), ssObj.end());
    ssObj << hash;

    // open output file, and associate with CAutoFile
    FILE* file = std::fopen(pathDB.string().c_str(), "wb");
    if (file == nullptr) {
        return error("%s : Failed to open file %s", __func__, pathDB.string());
    }

    CAutoFile fileout(file, SER_DISK, CLIENT_VERSION);
    if (fileout.IsNull()) {
        return error("%s : Failed to open file %s", __func__, pathDB.string());
    }

    // Write and commit header, data
    try {
        fileout << ssObj;
    } catch (const std::exception& e) {
        return error("%s : Serialize or I/O error - %s", __func__, e.what());
    }
    fileout.fclose();

    LogPrint("masternode", "Written info to mnpayments.dat  %dms\n", GetTimeMillis() - nStart);
    return true;
}

CMasternodePaymentDB::ReadResult CMasternodePaymentDB::Read(CMasternodePayments& objToLoad, bool fDryRun)
{
    const int64_t nStart = GetTimeMillis();

    // open input file, and associate with CAutoFile
    FILE* file = std::fopen(pathDB.string().c_str(), "rb");
    if (file == nullptr) {
        error("%s : Failed to open file %s", __func__, pathDB.string());
        return FileError;
    }

    CAutoFile filein(file, SER_DISK, CLIENT_VERSION);
    if (filein.IsNull()) {
        error("%s : Failed to open file %s", __func__, pathDB.string());
        return FileError;
    }

    int fileSize = 0;
    try {
        fileSize = static_cast<int>(boost::filesystem::file_size(pathDB));
    } catch (const std::exception& e) {
        error("%s : Unable to read file size %s (%s)", __func__, pathDB.string(), e.what());
        return FileError;
    }

    int dataSize = fileSize - static_cast<int>(sizeof(uint256));
    // Don't try to resize to a negative number if file is small
    if (dataSize < 0) {
        dataSize = 0;
    }

    std::vector<unsigned char> vchData;
    vchData.resize(static_cast<size_t>(dataSize));
    uint256 hashIn;

    // read data and checksum from file
    try {
        if (dataSize > 0) {
            filein.read(reinterpret_cast<char*>(&vchData[0]), dataSize);
        }
        filein >> hashIn;
    } catch (const std::exception& e) {
        error("%s : Deserialize or I/O error - %s", __func__, e.what());
        return HashReadError;
    }
    filein.fclose();

    CDataStream ssObj(vchData, SER_DISK, CLIENT_VERSION);

    // verify stored checksum matches input data
    const uint256 hashTmp = Hash(ssObj.begin(), ssObj.end());
    if (hashIn != hashTmp) {
        error("%s : Checksum mismatch, data corrupted", __func__);
        return IncorrectHash;
    }

    unsigned char pchMsgTmp[4];
    std::string strMagicMessageTmp;
    try {
        // de-serialize file header (masternode cache file specific magic message) and ..
        ssObj >> strMagicMessageTmp;

        // ... verify the message matches predefined one
        if (strMagicMessage != strMagicMessageTmp) {
            error("%s : Invalid masternode payment cache magic message", __func__);
            return IncorrectMagicMessage;
        }

        // de-serialize file header (network specific magic number) and ..
        ssObj >> FLATDATA(pchMsgTmp);

        // ... verify the network matches ours
        if (std::memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp))) {
            error("%s : Invalid network magic number", __func__);
            return IncorrectMagicNumber;
        }

        // de-serialize data into CMasternodePayments object
        ssObj >> objToLoad;
    } catch (const std::exception& e) {
        objToLoad.Clear();
        error("%s : Deserialize or I/O error - %s", __func__, e.what());
        return IncorrectFormat;
    }

    LogPrint("masternode", "Loaded info from mnpayments.dat  %dms\n", GetTimeMillis() - nStart);
    LogPrint("masternode", "  %s\n", objToLoad.ToString());

    if (!fDryRun) {
        LogPrint("masternode", "Masternode payments manager - cleaning....\n");
        objToLoad.CleanPaymentList();
        LogPrint("masternode", "Masternode payments manager - result:\n");
        LogPrint("masternode", "  %s\n", objToLoad.ToString());
    }

    return Ok;
}

void DumpMasternodePayments()
{
    const int64_t nStart = GetTimeMillis();

    CMasternodePaymentDB paymentdb;
    CMasternodePayments tempPayments;

    LogPrint("masternode", "Verifying mnpayments.dat format...\n");
    const CMasternodePaymentDB::ReadResult readResult = paymentdb.Read(tempPayments, true);

    // there was an error and it was not an error on file opening => do not proceed
    if (readResult == CMasternodePaymentDB::FileError) {
        LogPrint("masternode", "Missing payments file - mnpayments.dat, will try to recreate\n");
    } else if (readResult != CMasternodePaymentDB::Ok) {
        LogPrint("masternode", "Error reading mnpayments.dat: ");
        if (readResult == CMasternodePaymentDB::IncorrectFormat) {
            LogPrint("masternode", "magic is ok but data has invalid format, will try to recreate\n");
        } else {
            LogPrint("masternode", "file format is unknown or invalid, please fix it manually\n");
            return;
        }
    }

    LogPrint("masternode", "Writing info to mnpayments.dat...\n");
    paymentdb.Write(masternodePayments);

    LogPrint("masternode", "Payments dump finished  %dms\n", GetTimeMillis() - nStart);
}

bool IsBlockValueValid(const CBlock& block, CAmount nExpectedValue, CAmount nMinted)
{
    CBlockIndex* pindexPrev = chainActive.Tip();
    if (pindexPrev == nullptr) {
        return true;
    }

    int nHeight = 0;
    if (pindexPrev->GetBlockHash() == block.hashPrevBlock) {
        nHeight = pindexPrev->nHeight + 1;
    } else { // out of order
        BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
        if (mi != mapBlockIndex.end() && (*mi).second) {
            nHeight = (*mi).second->nHeight + 1;
        }
    }

    if (nHeight == 0) {
        LogPrint("masternode", "IsBlockValueValid() : WARNING: Couldn't find previous block\n");
    }

    if (!masternodeSync.IsSynced()) { // there is no budget data to use to check anything
        // super blocks will always be on these blocks, max 100 per budgeting
        if (nHeight % Params().GetBudgetCycleBlocks() < 100) {
            return true;
        }
        return nMinted <= nExpectedValue;
    }

    // we're synced and have data so check the budget schedule

    // are these blocks even enabled
    if (!IsSporkActive(SPORK_13_ENABLE_SUPERBLOCKS)) {
        return nMinted <= nExpectedValue;
    }

    if (budget.IsBudgetPaymentBlock(nHeight)) {
        // the value of the block is evaluated in CheckBlock
        return true;
    }

    return nMinted <= nExpectedValue;
}

bool IsBlockPayeeValid(const CBlock& block, int nBlockHeight)
{
    TrxValidationStatus transactionStatus = TrxValidationStatus::InValid;

    if (!masternodeSync.IsSynced()) { // there is no budget data to use to check anything -- find the longest chain
        LogPrint("mnpayments", "Client not synced, skipping block payee checks\n");
        return true;
    }

    const CTransaction& txNew = GetBlockNewTxForPayeeChecks(block);

    // check if it's a budget block
    if (IsSporkActive(SPORK_13_ENABLE_SUPERBLOCKS)) {
        if (budget.IsBudgetPaymentBlock(nBlockHeight)) {
            transactionStatus = budget.IsTransactionValid(txNew, nBlockHeight);
            if (transactionStatus == TrxValidationStatus::Valid) {
                return true;
            }

            if (transactionStatus == TrxValidationStatus::InValid) {
                LogPrint("masternode", "Invalid budget payment detected %s\n", txNew.ToString().c_str());
                if (IsSporkActive(SPORK_9_MASTERNODE_BUDGET_ENFORCEMENT)) {
                    return false;
                }
                LogPrint("masternode", "Budget enforcement is disabled, accepting block\n");
            }
        }
    }

    // If we end here the transaction was either InValid and Budget enforcement is disabled, or
    // a double budget payment (DoublePayment) was detected, or no/not enough masternode
    // votes (VoteThreshold) for a finalized budget were found.
    // In all cases a masternode will get the payment for this block.

    // check for masternode payee
    if (masternodePayments.IsTransactionValid(txNew, nBlockHeight)) {
        return true;
    }

    LogPrint("masternode", "Invalid mn payment detected %s\n", txNew.ToString().c_str());

    if (IsSporkActive(SPORK_8_MASTERNODE_PAYMENT_ENFORCEMENT)) {
        return false;
    }

    LogPrint("masternode", "Masternode payment enforcement is disabled, accepting block\n");
    return true;
}

void FillBlockPayee(CMutableTransaction& txNew, CAmount nFees, bool fProofOfStake, bool fZAGRStake)
{
    CBlockIndex* pindexPrev = chainActive.Tip();
    if (!pindexPrev) {
        return;
    }

    const int nextHeight = pindexPrev->nHeight + 1;
    if (IsSporkActive(SPORK_13_ENABLE_SUPERBLOCKS) && budget.IsBudgetPaymentBlock(nextHeight)) {
        budget.FillBlockPayee(txNew, nFees, fProofOfStake);
    } else {
        masternodePayments.FillBlockPayee(txNew, nFees, fProofOfStake, fZAGRStake);
    }
}

std::string GetRequiredPaymentsString(int nBlockHeight)
{
    if (IsSporkActive(SPORK_13_ENABLE_SUPERBLOCKS) && budget.IsBudgetPaymentBlock(nBlockHeight)) {
        return budget.GetRequiredPaymentsString(nBlockHeight);
    }
    return masternodePayments.GetRequiredPaymentsString(nBlockHeight);
}

void CMasternodePayments::FillBlockPayee(CMutableTransaction& txNew, int64_t /*nFees*/, bool fProofOfStake, bool fZAGRStake)
{
    CBlockIndex* pindexPrev = chainActive.Tip();
    if (!pindexPrev) {
        return;
    }

    bool hasPayment = true;
    CScript payee;

    // spork / schedule
    if (!masternodePayments.GetBlockPayee(pindexPrev->nHeight + 1, payee)) {
        // no masternode detected
        CMasternode* winningNode = mnodeman.GetCurrentMasterNode(1);
        if (winningNode) {
            payee = GetScriptForDestination(winningNode->pubKeyCollateralAddress.GetID());
        } else {
            LogPrint("masternode", "CreateNewBlock: Failed to detect masternode to pay\n");
            hasPayment = false;
        }
    }

    const int payHeight = pindexPrev->nHeight + 1;
    const CAmount blockValue = GetBlockValue(payHeight);
    const CAmount masternodePayment = GetMasternodePayment(payHeight, blockValue, 0, fZAGRStake);

    if (hasPayment) {
        if (fProofOfStake) {
            /** For Proof Of Stake vout[0] must be null.
             * Stake reward can be split into many different outputs, so we must
             * use vout.size() to align with several different cases.
             * An additional output is appended as the masternode payment.
             */
            const unsigned int i = txNew.vout.size();
            txNew.vout.resize(i + 1);
            txNew.vout[i].scriptPubKey = payee;
            txNew.vout[i].nValue = masternodePayment;

            // subtract mn payment from the stake reward
            // NOTE: original code used vout[1] and (i-1); keep behavior, but guard bounds.
            if (i > 0) {
                if (!txNew.vout[1].IsZerocoinMint() && (i - 1) < txNew.vout.size()) {
                    txNew.vout[i - 1].nValue -= masternodePayment;
                }
            }
        } else {
            txNew.vout.resize(2);
            txNew.vout[1].scriptPubKey = payee;
            txNew.vout[1].nValue = masternodePayment;
            txNew.vout[0].nValue = blockValue - masternodePayment;
        }

        CTxDestination address1;
        ExtractDestination(payee, address1);
        CBitcoinAddress address2(address1);

        LogPrint("masternode", "Masternode payment of %s to %s\n", FormatMoney(masternodePayment).c_str(), address2.ToString().c_str());
    }
}

int CMasternodePayments::GetMinMasternodePaymentsProto()
{
    if (IsSporkActive(SPORK_10_MASTERNODE_PAY_UPDATED_NODES))
        return ActiveProtocol(); // Allow only updated peers
    return MIN_PEER_PROTO_VERSION_BEFORE_ENFORCEMENT; // Also allow old peers as long as they are allowed to run
}

void CMasternodePayments::ProcessMessageMasternodePayments(CNode* pfrom, std::string& strCommand, CDataStream& vRecv)
{
    if (!masternodeSync.IsBlockchainSynced()) {
        return;
    }

    if (fLiteMode) {
        return; // disable all Obfuscation/Masternode related functionality
    }

    if (strCommand == "mnget") { // Masternode Payments Request Sync
        int nCountNeeded;
        vRecv >> nCountNeeded;

        if (Params().NetworkID() == CBaseChainParams::MAIN) {
            if (pfrom->HasFulfilledRequest("mnget")) {
                LogPrintf("CMasternodePayments::ProcessMessageMasternodePayments() : mnget - peer already asked me for the list\n");
                Misbehaving(pfrom->GetId(), 20);
                return;
            }
        }

        pfrom->FulfilledRequest("mnget");
        masternodePayments.Sync(pfrom, nCountNeeded);
        LogPrint("mnpayments", "mnget - Sent Masternode winners to peer %i\n", pfrom->GetId());
        return;
    }

    if (strCommand == "mnw") { // Masternode Payments Declare Winner
        CMasternodePaymentWinner winner;
        vRecv >> winner;

        if (pfrom->nVersion < ActiveProtocol()) {
            return;
        }

        int nHeight;
        {
            TRY_LOCK(cs_main, locked);
            if (!locked || chainActive.Tip() == nullptr) {
                return;
            }
            nHeight = chainActive.Tip()->nHeight;
        }

        if (masternodePayments.mapMasternodePayeeVotes.count(winner.GetHash())) {
            LogPrint("mnpayments", "mnw - Already seen - %s bestHeight %d\n", winner.GetHash().ToString().c_str(), nHeight);
            masternodeSync.AddedMasternodeWinner(winner.GetHash());
            return;
        }

        const int nFirstBlock = nHeight - static_cast<int>(mnodeman.CountEnabled() * 1.25);
        if (winner.nBlockHeight < nFirstBlock || winner.nBlockHeight > nHeight + 20) {
            LogPrint("mnpayments", "mnw - winner out of range - FirstBlock %d Height %d bestHeight %d\n", nFirstBlock, winner.nBlockHeight, nHeight);
            return;
        }

        std::string strError;
        if (!winner.IsValid(pfrom, strError)) {
            return;
        }

        if (!masternodePayments.CanVote(winner.vinMasternode.prevout, winner.nBlockHeight)) {
            return;
        }

        if (!winner.SignatureValid()) {
            if (masternodeSync.IsSynced()) {
                LogPrintf("CMasternodePayments::ProcessMessageMasternodePayments() : mnw - invalid signature\n");
                Misbehaving(pfrom->GetId(), 20);
            }
            // it could just be a non-synced masternode
            mnodeman.AskForMN(pfrom, winner.vinMasternode);
            return;
        }

        if (masternodePayments.AddWinningMasternode(winner)) {
            winner.Relay();
            masternodeSync.AddedMasternodeWinner(winner.GetHash());
        }
        return;
    }
}

bool CMasternodePaymentWinner::Sign(CKey& keyMasternode, CPubKey& pubKeyMasternode)
{
    std::string errorMessage;

    const std::string strMessage =
        vinMasternode.prevout.ToStringShort() + std::to_string(nBlockHeight) + payee.ToString();

    if (!obfuScationSigner.SignMessage(strMessage, errorMessage, vchSig, keyMasternode)) {
        LogPrint("masternode", "CMasternodePing::Sign() - Error: %s\n", errorMessage.c_str());
        return false;
    }

    if (!obfuScationSigner.VerifyMessage(pubKeyMasternode, vchSig, strMessage, errorMessage)) {
        LogPrint("masternode", "CMasternodePing::Sign() - Error: %s\n", errorMessage.c_str());
        return false;
    }

    return true;
}

bool CMasternodePayments::GetBlockPayee(int nBlockHeight, CScript& payee)
{
    if (mapMasternodeBlocks.count(nBlockHeight)) {
        return mapMasternodeBlocks[nBlockHeight].GetPayee(payee);
    }
    return false;
}

// Is this masternode scheduled to get paid soon?
// -- Only look ahead up to 8 blocks to allow for propagation of the latest 2 winners
bool CMasternodePayments::IsScheduled(CMasternode& mn, int nNotBlockHeight)
{
    LOCK(cs_mapMasternodeBlocks);

    int nHeight;
    {
        TRY_LOCK(cs_main, locked);
        if (!locked || chainActive.Tip() == nullptr) {
            return false;
        }
        nHeight = chainActive.Tip()->nHeight;
    }

    const CScript mnpayee = GetScriptForDestination(mn.pubKeyCollateralAddress.GetID());

    CScript payee;
    for (int64_t h = nHeight; h <= nHeight + 8; h++) {
        if (h == nNotBlockHeight) {
            continue;
        }
        if (mapMasternodeBlocks.count(h)) {
            if (mapMasternodeBlocks[h].GetPayee(payee)) {
                if (mnpayee == payee) {
                    return true;
                }
            }
        }
    }

    return false;
}

bool CMasternodePayments::AddWinningMasternode(CMasternodePaymentWinner& winnerIn)
{
    uint256 blockHash = 0;
    if (!GetBlockHash(blockHash, winnerIn.nBlockHeight - 100)) {
        return false;
    }

    {
        LOCK2(cs_mapMasternodePayeeVotes, cs_mapMasternodeBlocks);

        if (mapMasternodePayeeVotes.count(winnerIn.GetHash())) {
            return false;
        }

        mapMasternodePayeeVotes[winnerIn.GetHash()] = winnerIn;

        if (!mapMasternodeBlocks.count(winnerIn.nBlockHeight)) {
            CMasternodeBlockPayees blockPayees(winnerIn.nBlockHeight);
            mapMasternodeBlocks[winnerIn.nBlockHeight] = blockPayees;
        }
    }

    mapMasternodeBlocks[winnerIn.nBlockHeight].AddPayee(winnerIn.payee, 1);
    return true;
}

bool CMasternodeBlockPayees::IsTransactionValid(const CTransaction& txNew)
{
    LOCK(cs_vecPayments);

    int nMaxSignatures = 0;
    int nMasternode_Drift_Count = 0;

    std::string strPayeesPossible;

    const CAmount nReward = GetBlockValue(nBlockHeight);

    if (IsSporkActive(SPORK_8_MASTERNODE_PAYMENT_ENFORCEMENT)) {
        // Get a stable number of masternodes by ignoring newly activated (< 8000 sec old) masternodes
        nMasternode_Drift_Count = mnodeman.stable_size() + Params().MasternodeCountDrift();
    } else {
        // Account for the fact that all peers do not see the same masternode count.
        // An allowance of being off our masternode count is given.
        // We only need to look at an increased masternode count because as count increases, the reward decreases.
        // This code only checks for mnPayment >= required, so it only makes sense to check the max node count allowed.
        nMasternode_Drift_Count = mnodeman.size() + Params().MasternodeCountDrift();
    }

    const CAmount requiredMasternodePayment =
        GetMasternodePayment(nBlockHeight, nReward, nMasternode_Drift_Count, txNew.HasZerocoinSpendInputs());

    // require at least 6 signatures
    for (CMasternodePayee& payee : vecPayments) {
        if (payee.nVotes >= nMaxSignatures && payee.nVotes >= MNPAYMENTS_SIGNATURES_REQUIRED) {
            nMaxSignatures = payee.nVotes;
        }
    }

    // If we don't have at least 6 signatures on a payee, approve whichever is the longest chain
    if (nMaxSignatures < MNPAYMENTS_SIGNATURES_REQUIRED) {
        return true;
    }

    for (CMasternodePayee& payee : vecPayments) {
        bool found = false;

        for (const CTxOut& out : txNew.vout) {
            if (payee.scriptPubKey == out.scriptPubKey) {
                if (out.nValue >= requiredMasternodePayment) {
                    found = true;
                } else {
                    LogPrint("masternode", "Masternode payment is out of drift range. Paid=%s Min=%s\n",
                             FormatMoney(out.nValue).c_str(), FormatMoney(requiredMasternodePayment).c_str());
                }
            }
        }

        if (payee.nVotes >= MNPAYMENTS_SIGNATURES_REQUIRED) {
            if (found) {
                return true;
            }

            CTxDestination address1;
            ExtractDestination(payee.scriptPubKey, address1);
            CBitcoinAddress address2(address1);

            if (strPayeesPossible.empty()) {
                strPayeesPossible += address2.ToString();
            } else {
                strPayeesPossible += "," + address2.ToString();
            }
        }
    }

    LogPrint("masternode", "CMasternodePayments::IsTransactionValid - Missing required payment of %s to %s\n",
             FormatMoney(requiredMasternodePayment).c_str(), strPayeesPossible.c_str());
    return false;
}

std::string CMasternodeBlockPayees::GetRequiredPaymentsString()
{
    LOCK(cs_vecPayments);

    std::string ret = "Unknown";

    for (CMasternodePayee& payee : vecPayments) {
        CTxDestination address1;
        ExtractDestination(payee.scriptPubKey, address1);
        CBitcoinAddress address2(address1);

        if (ret != "Unknown") {
            ret += ", " + address2.ToString() + ":" + std::to_string(payee.nVotes);
        } else {
            ret = address2.ToString() + ":" + std::to_string(payee.nVotes);
        }
    }

    return ret;
}

std::string CMasternodePayments::GetRequiredPaymentsString(int nBlockHeight)
{
    LOCK(cs_mapMasternodeBlocks);

    if (mapMasternodeBlocks.count(nBlockHeight)) {
        return mapMasternodeBlocks[nBlockHeight].GetRequiredPaymentsString();
    }

    return "Unknown";
}

bool CMasternodePayments::IsTransactionValid(const CTransaction& txNew, int nBlockHeight)
{
    LOCK(cs_mapMasternodeBlocks);

    if (mapMasternodeBlocks.count(nBlockHeight)) {
        return mapMasternodeBlocks[nBlockHeight].IsTransactionValid(txNew);
    }

    return true;
}

void CMasternodePayments::CleanPaymentList()
{
    LOCK2(cs_mapMasternodePayeeVotes, cs_mapMasternodeBlocks);

    int nHeight;
    {
        TRY_LOCK(cs_main, locked);
        if (!locked || chainActive.Tip() == nullptr) {
            return;
        }
        nHeight = chainActive.Tip()->nHeight;
    }

    // keep up to five cycles for historical sake
    const int nLimit = std::max(static_cast<int>(mnodeman.size() * 1.25), 1000);

    std::map<uint256, CMasternodePaymentWinner>::iterator it = mapMasternodePayeeVotes.begin();
    while (it != mapMasternodePayeeVotes.end()) {
        const CMasternodePaymentWinner& winner = (*it).second;

        if (nHeight - winner.nBlockHeight > nLimit) {
            LogPrint("mnpayments", "CMasternodePayments::CleanPaymentList - Removing old Masternode payment - block %d\n", winner.nBlockHeight);
            masternodeSync.mapSeenSyncMNW.erase((*it).first);
            mapMasternodePayeeVotes.erase(it++);
            mapMasternodeBlocks.erase(winner.nBlockHeight);
        } else {
            ++it;
        }
    }
}

bool CMasternodePaymentWinner::IsValid(CNode* pnode, std::string& strError)
{
    CMasternode* pmn = mnodeman.Find(vinMasternode);

    if (!pmn) {
        strError = strprintf("Unknown Masternode %s", vinMasternode.prevout.hash.ToString());
        LogPrint("masternode", "CMasternodePaymentWinner::IsValid - %s\n", strError);
        mnodeman.AskForMN(pnode, vinMasternode);
        return false;
    }

    if (pmn->protocolVersion < ActiveProtocol()) {
        strError = strprintf("Masternode protocol too old %d - req %d", pmn->protocolVersion, ActiveProtocol());
        LogPrint("masternode", "CMasternodePaymentWinner::IsValid - %s\n", strError);
        return false;
    }

    const int n = mnodeman.GetMasternodeRank(vinMasternode, nBlockHeight - 100, ActiveProtocol());

    if (n > MNPAYMENTS_SIGNATURES_TOTAL) {
        // It's common to have masternodes mistakenly think they are in the top 10.
        // We don't want to print all of these messages, or punish them unless they're way off.
        if (n > MNPAYMENTS_SIGNATURES_TOTAL * 2) {
            strError = strprintf("Masternode not in the top %d (%d)", MNPAYMENTS_SIGNATURES_TOTAL * 2, n);
            LogPrint("masternode", "CMasternodePaymentWinner::IsValid - %s\n", strError);
            // if (masternodeSync.IsSynced()) Misbehaving(pnode->GetId(), 20);
        }
        return false;
    }

    return true;
}

bool CMasternodePayments::ProcessBlock(int nBlockHeight)
{
    if (!fMasterNode) {
        return false;
    }

    // reference node - hybrid mode
    const int n = mnodeman.GetMasternodeRank(activeMasternode.vin, nBlockHeight - 100, ActiveProtocol());

    if (n == -1) {
        LogPrint("mnpayments", "CMasternodePayments::ProcessBlock - Unknown Masternode\n");
        return false;
    }

    if (n > MNPAYMENTS_SIGNATURES_TOTAL) {
        LogPrint("mnpayments", "CMasternodePayments::ProcessBlock - Masternode not in the top %d (%d)\n", MNPAYMENTS_SIGNATURES_TOTAL, n);
        return false;
    }

    if (nBlockHeight <= nLastBlockHeight) {
        return false;
    }

    CMasternodePaymentWinner newWinner(activeMasternode.vin);

    if (budget.IsBudgetPaymentBlock(nBlockHeight)) {
        // budget payment block -- handled by the budgeting software
    } else {
        LogPrint("masternode", "CMasternodePayments::ProcessBlock() Start nHeight %d - vin %s. \n",
                 nBlockHeight, activeMasternode.vin.prevout.hash.ToString());

        // pay to the oldest MN that still had no payment but its input is old enough and it was active long enough
        int nCount = 0;
        CMasternode* pmn = mnodeman.GetNextMasternodeInQueueForPayment(nBlockHeight, true, nCount);

        if (pmn != nullptr) {
            LogPrint("masternode", "CMasternodePayments::ProcessBlock() Found by FindOldestNotInVec \n");

            newWinner.nBlockHeight = nBlockHeight;

            const CScript payee = GetScriptForDestination(pmn->pubKeyCollateralAddress.GetID());
            newWinner.AddPayee(payee);

            CTxDestination address1;
            ExtractDestination(payee, address1);
            CBitcoinAddress address2(address1);

            LogPrint("masternode", "CMasternodePayments::ProcessBlock() Winner payee %s nHeight %d. \n",
                     address2.ToString().c_str(), newWinner.nBlockHeight);
        } else {
            LogPrint("masternode", "CMasternodePayments::ProcessBlock() Failed to find masternode to pay\n");
        }
    }

    std::string errorMessage;
    CPubKey pubKeyMasternode;
    CKey keyMasternode;

    if (!obfuScationSigner.SetKey(strMasterNodePrivKey, errorMessage, keyMasternode, pubKeyMasternode)) {
        LogPrint("masternode", "CMasternodePayments::ProcessBlock() - Error upon calling SetKey: %s\n", errorMessage.c_str());
        return false;
    }

    LogPrint("masternode", "CMasternodePayments::ProcessBlock() - Signing Winner\n");
    if (newWinner.Sign(keyMasternode, pubKeyMasternode)) {
        LogPrint("masternode", "CMasternodePayments::ProcessBlock() - AddWinningMasternode\n");

        if (AddWinningMasternode(newWinner)) {
            newWinner.Relay();
            nLastBlockHeight = nBlockHeight;
            return true;
        }
    }

    return false;
}

void CMasternodePaymentWinner::Relay()
{
    CInv inv(MSG_MASTERNODE_WINNER, GetHash());
    RelayInv(inv);
}

bool CMasternodePaymentWinner::SignatureValid()
{
    CMasternode* pmn = mnodeman.Find(vinMasternode);

    if (pmn != nullptr) {
        const std::string strMessage =
            vinMasternode.prevout.ToStringShort() + std::to_string(nBlockHeight) + payee.ToString();

        std::string errorMessage;
        if (!obfuScationSigner.VerifyMessage(pmn->pubKeyMasternode, vchSig, strMessage, errorMessage)) {
            return error("CMasternodePaymentWinner::SignatureValid() - Got bad Masternode address signature %s\n",
                         vinMasternode.prevout.hash.ToString());
        }

        return true;
    }

    return false;
}

void CMasternodePayments::Sync(CNode* node, int nCountNeeded)
{
    LOCK(cs_mapMasternodePayeeVotes);

    int nHeight;
    {
        TRY_LOCK(cs_main, locked);
        if (!locked || chainActive.Tip() == nullptr) {
            return;
        }
        nHeight = chainActive.Tip()->nHeight;
    }

    int nCount = static_cast<int>(mnodeman.CountEnabled() * 1.25);
    if (nCountNeeded > nCount) {
        nCountNeeded = nCount;
    }

    int nInvCount = 0;
    std::map<uint256, CMasternodePaymentWinner>::iterator it = mapMasternodePayeeVotes.begin();
    while (it != mapMasternodePayeeVotes.end()) {
        const CMasternodePaymentWinner& winner = (*it).second;
        if (winner.nBlockHeight >= nHeight - nCountNeeded && winner.nBlockHeight <= nHeight + 20) {
            node->PushInventory(CInv(MSG_MASTERNODE_WINNER, winner.GetHash()));
            nInvCount++;
        }
        ++it;
    }

    node->PushMessage("ssc", MASTERNODE_SYNC_MNW, nInvCount);
}

std::string CMasternodePayments::ToString() const
{
    std::ostringstream info;
    info << "Votes: " << (int)mapMasternodePayeeVotes.size() << ", Blocks: " << (int)mapMasternodeBlocks.size();
    return info.str();
}

int CMasternodePayments::GetOldestBlock()
{
    LOCK(cs_mapMasternodeBlocks);

    int nOldestBlock = std::numeric_limits<int>::max();

    std::map<int, CMasternodeBlockPayees>::iterator it = mapMasternodeBlocks.begin();
    while (it != mapMasternodeBlocks.end()) {
        if ((*it).first < nOldestBlock) {
            nOldestBlock = (*it).first;
        }
        ++it;
    }

    return nOldestBlock;
}

int CMasternodePayments::GetNewestBlock()
{
    LOCK(cs_mapMasternodeBlocks);

    int nNewestBlock = 0;

    std::map<int, CMasternodeBlockPayees>::iterator it = mapMasternodeBlocks.begin();
    while (it != mapMasternodeBlocks.end()) {
        if ((*it).first > nNewestBlock) {
            nNewestBlock = (*it).first;
        }
        ++it;
    }

    return nNewestBlock;
}