text: // Copyright (c) 2014-2017 The Dash Core developers
  // Copyright (c) 2018 The TOUR Coin Core developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "activemasternode.h"
  #include "governance-classes.h"
  #include "masternode-payments.h"
  #include "masternode-sync.h"
  #include "masternodeman.h"
  #include "messagesigner.h"
  #include "netfulfilledman.h"
  #include "spork.h"
  #include "util.h"
  
  #include <boost/lexical_cast.hpp>
  
  /** Object for who's going to get paid on which blocks */
  CMasternodePayments mnpayments;
  
  CCriticalSection cs_vecPayees;
  CCriticalSection cs_mapMasternodeBlocks;
  CCriticalSection cs_mapMasternodePaymentVotes;
  
  /**
  * IsBlockValueValid
  *
  *   Determine if coinbase outgoing created money is the correct value
  *
  *   Why is this needed?
  *   - In TOUR some blocks are superblocks, which output much higher amounts of coins
  *   - Otherblocks are 10% lower in outgoing value, so in total, no extra coins are created
  *   - When non-superblocks are detected, the normal schedule should be maintained
  */
  
  bool IsBlockValueValid(const CBlock& block, int nBlockHeight, CAmount blockReward, std::string &strErrorRet)
  {
      strErrorRet = "";
  
      bool isBlockRewardValueMet = (block.vtx[0].GetValueOut() <= blockReward);
      if(fDebug) LogPrintf("block.vtx[0].GetValueOut() %lld <= blockReward %lld\n", block.vtx[0].GetValueOut(), blockReward);
  
      // we are still using budgets, but we have no data about them anymore,
      // all we know is predefined budget cycle and window
  
      const Consensus::Params& consensusParams = Params().GetConsensus();
  
      if(nBlockHeight < consensusParams.nSuperblockStartBlock) {
          int nOffset = nBlockHeight % consensusParams.nBudgetPaymentsCycleBlocks;
          if(nBlockHeight >= consensusParams.nBudgetPaymentsStartBlock &&
              nOffset < consensusParams.nBudgetPaymentsWindowBlocks) {
              // NOTE: make sure SPORK_13_OLD_SUPERBLOCK_FLAG is disabled when 12.1 starts to go live
              if(masternodeSync.IsSynced() && !sporkManager.IsSporkActive(SPORK_13_OLD_SUPERBLOCK_FLAG)) {
                  // no budget blocks should be accepted here, if SPORK_13_OLD_SUPERBLOCK_FLAG is disabled
                  LogPrint("gobject", "IsBlockValueValid -- Client synced but budget spork is disabled, checking block value against block reward\n");
                  if(!isBlockRewardValueMet) {
                      strErrorRet = strprintf("coinbase pays too much at height %d (actual=%d vs limit=%d), exceeded block reward, budgets are disabled",
                                              nBlockHeight, block.vtx[0].GetValueOut(), blockReward);
                  }
                  return isBlockRewardValueMet;
              }
              LogPrint("gobject", "IsBlockValueValid -- WARNING: Skipping budget block value checks, accepting block\n");
              // TODO: reprocess blocks to make sure they are legit?
              return true;
          }
          // LogPrint("gobject", "IsBlockValueValid -- Block is not in budget cycle window, checking block value against block reward\n");
          if(!isBlockRewardValueMet) {
              strErrorRet = strprintf("coinbase pays too much at height %d (actual=%d vs limit=%d), exceeded block reward, block is not in budget cycle window",
                                      nBlockHeight, block.vtx[0].GetValueOut(), blockReward);
          }
          return isBlockRewardValueMet;
      }
  
      // superblocks started
  
      CAmount nSuperblockMaxValue =  blockReward + CSuperblock::GetPaymentsLimit(nBlockHeight);
      bool isSuperblockMaxValueMet = (block.vtx[0].GetValueOut() <= nSuperblockMaxValue);
  
      LogPrint("gobject", "block.vtx[0].GetValueOut() %lld <= nSuperblockMaxValue %lld\n", block.vtx[0].GetValueOut(), nSuperblockMaxValue);
  
      if(!masternodeSync.IsSynced()) {
          // not enough data but at least it must NOT exceed superblock max value
          if(CSuperblock::IsValidBlockHeight(nBlockHeight)) {
              if(fDebug) LogPrintf("IsBlockPayeeValid -- WARNING: Client not synced, checking superblock max bounds only\n");
              if(!isSuperblockMaxValueMet) {
                  strErrorRet = strprintf("coinbase pays too much at height %d (actual=%d vs limit=%d), exceeded superblock max value",
                                          nBlockHeight, block.vtx[0].GetValueOut(), nSuperblockMaxValue);
              }
              return isSuperblockMaxValueMet;
          }
          if(!isBlockRewardValueMet) {
              strErrorRet = strprintf("coinbase pays too much at height %d (actual=%d vs limit=%d), exceeded block reward, only regular blocks are allowed at this height",
                                      nBlockHeight, block.vtx[0].GetValueOut(), blockReward);
          }
          // it MUST be a regular block otherwise
          return isBlockRewardValueMet;
      }
  
      // we are synced, let's try to check as much data as we can
  
      if(sporkManager.IsSporkActive(SPORK_9_SUPERBLOCKS_ENABLED)) {
          if(CSuperblockManager::IsSuperblockTriggered(nBlockHeight)) {
              if(CSuperblockManager::IsValid(block.vtx[0], nBlockHeight, blockReward)) {
                  LogPrint("gobject", "IsBlockValueValid -- Valid superblock at height %d: %s", nBlockHeight, block.vtx[0].ToString());
                  // all checks are done in CSuperblock::IsValid, nothing to do here
                  return true;
              }
  
              // triggered but invalid? that's weird
              LogPrintf("IsBlockValueValid -- ERROR: Invalid superblock detected at height %d: %s", nBlockHeight, block.vtx[0].ToString());
              // should NOT allow invalid superblocks, when superblocks are enabled
              strErrorRet = strprintf("invalid superblock detected at height %d", nBlockHeight);
              return false;
          }
          LogPrint("gobject", "IsBlockValueValid -- No triggered superblock detected at height %d\n", nBlockHeight);
          if(!isBlockRewardValueMet) {
              strErrorRet = strprintf("coinbase pays too much at height %d (actual=%d vs limit=%d), exceeded block reward, no triggered superblock detected",
                                      nBlockHeight, block.vtx[0].GetValueOut(), blockReward);
          }
      } else {
          // should NOT allow superblocks at all, when superblocks are disabled
          LogPrint("gobject", "IsBlockValueValid -- Superblocks are disabled, no superblocks allowed\n");
          if(!isBlockRewardValueMet) {
              strErrorRet = strprintf("coinbase pays too much at height %d (actual=%d vs limit=%d), exceeded block reward, superblocks are disabled",
                                      nBlockHeight, block.vtx[0].GetValueOut(), blockReward);
          }
      }
  
      // it MUST be a regular block
      return isBlockRewardValueMet;
  }
  
  bool IsBlockPayeeValid(const CTransaction& txNew, int nBlockHeight, CAmount blockReward)
  {
      if(!masternodeSync.IsSynced()) {
          //there is no budget data to use to check anything, let's just accept the longest chain
          if(fDebug) LogPrintf("IsBlockPayeeValid -- WARNING: Client not synced, skipping block payee checks\n");
          return true;
      }
  
      // we are still using budgets, but we have no data about them anymore,
      // we can only check masternode payments
  
      const Consensus::Params& consensusParams = Params().GetConsensus();
  
      if(nBlockHeight < consensusParams.nSuperblockStartBlock) {
          if(mnpayments.IsTransactionValid(txNew, nBlockHeight)) {
              LogPrint("mnpayments", "IsBlockPayeeValid -- Valid masternode payment at height %d: %s", nBlockHeight, txNew.ToString());
              return true;
          }
  
          int nOffset = nBlockHeight % consensusParams.nBudgetPaymentsCycleBlocks;
          if(nBlockHeight >= consensusParams.nBudgetPaymentsStartBlock &&
              nOffset < consensusParams.nBudgetPaymentsWindowBlocks) {
              if(!sporkManager.IsSporkActive(SPORK_13_OLD_SUPERBLOCK_FLAG)) {
                  // no budget blocks should be accepted here, if SPORK_13_OLD_SUPERBLOCK_FLAG is disabled
                  LogPrint("gobject", "IsBlockPayeeValid -- ERROR: Client synced but budget spork is disabled and masternode payment is invalid\n");
                  return false;
              }
              // NOTE: this should never happen in real, SPORK_13_OLD_SUPERBLOCK_FLAG MUST be disabled when 12.1 starts to go live
              LogPrint("gobject", "IsBlockPayeeValid -- WARNING: Probably valid budget block, have no data, accepting\n");
              // TODO: reprocess blocks to make sure they are legit?
              return true;
          }
  
          if(sporkManager.IsSporkActive(SPORK_8_MASTERNODE_PAYMENT_ENFORCEMENT)) {
              LogPrintf("IsBlockPayeeValid -- ERROR: Invalid masternode payment detected at height %d: %s", nBlockHeight, txNew.ToString());
              return false;
          }
  
          LogPrintf("IsBlockPayeeValid -- WARNING: Masternode payment enforcement is disabled, accepting any payee\n");
          return true;
      }
  
      // superblocks started
      // SEE IF THIS IS A VALID SUPERBLOCK
  
      if(sporkManager.IsSporkActive(SPORK_9_SUPERBLOCKS_ENABLED)) {
          if(CSuperblockManager::IsSuperblockTriggered(nBlockHeight)) {
              if(CSuperblockManager::IsValid(txNew, nBlockHeight, blockReward)) {
                  LogPrint("gobject", "IsBlockPayeeValid -- Valid superblock at height %d: %s", nBlockHeight, txNew.ToString());
                  return true;
              }
  
              LogPrintf("IsBlockPayeeValid -- ERROR: Invalid superblock detected at height %d: %s", nBlockHeight, txNew.ToString());
              // should NOT allow such superblocks, when superblocks are enabled
              return false;
          }
          // continue validation, should pay MN
          LogPrint("gobject", "IsBlockPayeeValid -- No triggered superblock detected at height %d\n", nBlockHeight);
      } else {
          // should NOT allow superblocks at all, when superblocks are disabled
          LogPrint("gobject", "IsBlockPayeeValid -- Superblocks are disabled, no superblocks allowed\n");
      }
  
      // IF THIS ISN'T A SUPERBLOCK OR SUPERBLOCK IS INVALID, IT SHOULD PAY A MASTERNODE DIRECTLY
      if(mnpayments.IsTransactionValid(txNew, nBlockHeight)) {
          LogPrint("mnpayments", "IsBlockPayeeValid -- Valid masternode payment at height %d: %s", nBlockHeight, txNew.ToString());
          return true;
      }
  
      if(sporkManager.IsSporkActive(SPORK_8_MASTERNODE_PAYMENT_ENFORCEMENT)) {
          LogPrintf("IsBlockPayeeValid -- ERROR: Invalid masternode payment detected at height %d: %s", nBlockHeight, txNew.ToString());
          return false;
      }
  
      LogPrintf("IsBlockPayeeValid -- WARNING: Masternode payment enforcement is disabled, accepting any payee\n");
      return true;
  }
  
  void FillBlockPayments(CMutableTransaction& txNew, int nBlockHeight, CAmount blockReward, CTxOut& txoutMasternodeRet, std::vector<CTxOut>& voutSuperblockRet)
  {
      // only create superblocks if spork is enabled AND if superblock is actually triggered
      // (height should be validated inside)
      if(sporkManager.IsSporkActive(SPORK_9_SUPERBLOCKS_ENABLED) &&
          CSuperblockManager::IsSuperblockTriggered(nBlockHeight)) {
              LogPrint("gobject", "FillBlockPayments -- triggered superblock creation at height %d\n", nBlockHeight);
              CSuperblockManager::CreateSuperblock(txNew, nBlockHeight, voutSuperblockRet);
              return;
      }
  
      // FILL BLOCK PAYEE WITH MASTERNODE PAYMENT OTHERWISE
      mnpayments.FillBlockPayee(txNew, nBlockHeight, blockReward, txoutMasternodeRet);
      LogPrint("mnpayments", "FillBlockPayments -- nBlockHeight %d blockReward %lld txoutMasternodeRet %s txNew %s",
                              nBlockHeight, blockReward, txoutMasternodeRet.ToString(), txNew.ToString());
  }
  
  std::string GetRequiredPaymentsString(int nBlockHeight)
  {
      // IF WE HAVE A ACTIVATED TRIGGER FOR THIS HEIGHT - IT IS A SUPERBLOCK, GET THE REQUIRED PAYEES
      if(CSuperblockManager::IsSuperblockTriggered(nBlockHeight)) {
          return CSuperblockManager::GetRequiredPaymentsString(nBlockHeight);
      }
  
      // OTHERWISE, PAY MASTERNODE
      return mnpayments.GetRequiredPaymentsString(nBlockHeight);
  }
  
  void CMasternodePayments::Clear()
  {
      LOCK2(cs_mapMasternodeBlocks, cs_mapMasternodePaymentVotes);
      mapMasternodeBlocks.clear();
      mapMasternodePaymentVotes.clear();
  }
  
  bool CMasternodePayments::CanVote(COutPoint outMasternode, int nBlockHeight)
  {
      LOCK(cs_mapMasternodePaymentVotes);
  
      if (mapMasternodesLastVote.count(outMasternode) && mapMasternodesLastVote[outMasternode] == nBlockHeight) {
          return false;
      }
  
      //record this masternode voted
      mapMasternodesLastVote[outMasternode] = nBlockHeight;
      return true;
  }
  
  /**
  *   FillBlockPayee
  *
  *   Fill Masternode ONLY payment block
  */
  
  void CMasternodePayments::FillBlockPayee(CMutableTransaction& txNew, int nBlockHeight, CAmount blockReward, CTxOut& txoutMasternodeRet)
  {
      // make sure it's not filled yet
      txoutMasternodeRet = CTxOut();
  
      CScript payee;
  
      if(!mnpayments.GetBlockPayee(nBlockHeight, payee)) {
          // no masternode detected...
          int nCount = 0;
          masternode_info_t mnInfo;
          if(!mnodeman.GetNextMasternodeInQueueForPayment(nBlockHeight, true, nCount, mnInfo)) {
              // ...and we can't calculate it on our own
              LogPrintf("CMasternodePayments::FillBlockPayee -- Failed to detect masternode to pay\n");
              return;
          }
          // fill payee with locally calculated winner and hope for the best
          payee = GetScriptForDestination(mnInfo.pubKeyCollateralAddress.GetID());
      }
  
      // GET MASTERNODE PAYMENT VARIABLES SETUP
      CAmount masternodePayment = GetMasternodePayment(nBlockHeight, blockReward);
  
      // split reward between miner ...
      txNew.vout[0].nValue -= masternodePayment;
      // ... and masternode
      txoutMasternodeRet = CTxOut(masternodePayment, payee);
      txNew.vout.push_back(txoutMasternodeRet);
  
      CTxDestination address1;
      ExtractDestination(payee, address1);
      CBitcoinAddress address2(address1);
  
      LogPrintf("CMasternodePayments::FillBlockPayee -- Masternode payment %lld to %s\n", masternodePayment, address2.ToString());
  }
  
  int CMasternodePayments::GetMinMasternodePaymentsProto() {
      return sporkManager.IsSporkActive(SPORK_10_MASTERNODE_PAY_UPDATED_NODES)
              ? MIN_MASTERNODE_PAYMENT_PROTO_VERSION_2
              : MIN_MASTERNODE_PAYMENT_PROTO_VERSION_1;
  }
  
  void CMasternodePayments::ProcessMessage(CNode* pfrom, std::string& strCommand, CDataStream& vRecv, CConnman& connman)
  {
      if(fLiteMode) return; // disable all TOUR specific functionality
  
      if (strCommand == NetMsgType::MASTERNODEPAYMENTSYNC) { //Masternode Payments Request Sync
  
          // Ignore such requests until we are fully synced.
          // We could start processing this after masternode list is synced
          // but this is a heavy one so it's better to finish sync first.
          if (!masternodeSync.IsSynced()) return;
  
          int nCountNeeded;
          vRecv >> nCountNeeded;
  
          if(netfulfilledman.HasFulfilledRequest(pfrom->addr, NetMsgType::MASTERNODEPAYMENTSYNC)) {
              // Asking for the payments list multiple times in a short period of time is no good
              LogPrintf("MASTERNODEPAYMENTSYNC -- peer already asked me for the list, peer=%d\n", pfrom->id);
              Misbehaving(pfrom->GetId(), 20);
              return;
          }
          netfulfilledman.AddFulfilledRequest(pfrom->addr, NetMsgType::MASTERNODEPAYMENTSYNC);
  
          Sync(pfrom, connman);
          LogPrintf("MASTERNODEPAYMENTSYNC -- Sent Masternode payment votes to peer %d\n", pfrom->id);
  
      } else if (strCommand == NetMsgType::MASTERNODEPAYMENTVOTE) { // Masternode Payments Vote for the Winner
  
          CMasternodePaymentVote vote;
          vRecv >> vote;
  
          if(pfrom->nVersion < GetMinMasternodePaymentsProto()) return;
  
          uint256 nHash = vote.GetHash();
  
          pfrom->setAskFor.erase(nHash);
  
          // TODO: clear setAskFor for MSG_MASTERNODE_PAYMENT_BLOCK too
  
          // Ignore any payments messages until masternode list is synced
          if(!masternodeSync.IsMasternodeListSynced()) return;
  
          {
              LOCK(cs_mapMasternodePaymentVotes);
              if(mapMasternodePaymentVotes.count(nHash)) {
                  LogPrint("mnpayments", "MASTERNODEPAYMENTVOTE -- hash=%s, nHeight=%d seen\n", nHash.ToString(), nCachedBlockHeight);
                  return;
              }
  
              // Avoid processing same vote multiple times
              mapMasternodePaymentVotes[nHash] = vote;
              // but first mark vote as non-verified,
              // AddPaymentVote() below should take care of it if vote is actually ok
              mapMasternodePaymentVotes[nHash].MarkAsNotVerified();
          }
  
          int nFirstBlock = nCachedBlockHeight - GetStorageLimit();
          if(vote.nBlockHeight < nFirstBlock || vote.nBlockHeight > nCachedBlockHeight+20) {
              LogPrint("mnpayments", "MASTERNODEPAYMENTVOTE -- vote out of range: nFirstBlock=%d, nBlockHeight=%d, nHeight=%d\n", nFirstBlock, vote.nBlockHeight, nCachedBlockHeight);
              return;
          }
  
          std::string strError = "";
          if(!vote.IsValid(pfrom, nCachedBlockHeight, strError, connman)) {
              LogPrint("mnpayments", "MASTERNODEPAYMENTVOTE -- invalid message, error: %s\n", strError);
              return;
          }
  
          if(!CanVote(vote.vinMasternode.prevout, vote.nBlockHeight)) {
              LogPrintf("MASTERNODEPAYMENTVOTE -- masternode already voted, masternode=%s\n", vote.vinMasternode.prevout.ToStringShort());
              return;
          }
  
          masternode_info_t mnInfo;
          if(!mnodeman.GetMasternodeInfo(vote.vinMasternode.prevout, mnInfo)) {
              // mn was not found, so we can't check vote, some info is probably missing
              LogPrintf("MASTERNODEPAYMENTVOTE -- masternode is missing %s\n", vote.vinMasternode.prevout.ToStringShort());
              mnodeman.AskForMN(pfrom, vote.vinMasternode.prevout, connman);
              return;
          }
  
          int nDos = 0;
          if(!vote.CheckSignature(mnInfo.pubKeyMasternode, nCachedBlockHeight, nDos)) {
              if(nDos) {
                  LogPrintf("MASTERNODEPAYMENTVOTE -- ERROR: invalid signature\n");
                  Misbehaving(pfrom->GetId(), nDos);
              } else {
                  // only warn about anything non-critical (i.e. nDos == 0) in debug mode
                  LogPrint("mnpayments", "MASTERNODEPAYMENTVOTE -- WARNING: invalid signature\n");
              }
              // Either our info or vote info could be outdated.
              // In case our info is outdated, ask for an update,
              mnodeman.AskForMN(pfrom, vote.vinMasternode.prevout, connman);
              // but there is nothing we can do if vote info itself is outdated
              // (i.e. it was signed by a mn which changed its key),
              // so just quit here.
              return;
          }
  
          CTxDestination address1;
          ExtractDestination(vote.payee, address1);
          CBitcoinAddress address2(address1);
  
          LogPrint("mnpayments", "MASTERNODEPAYMENTVOTE -- vote: address=%s, nBlockHeight=%d, nHeight=%d, prevout=%s, hash=%s new\n",
                      address2.ToString(), vote.nBlockHeight, nCachedBlockHeight, vote.vinMasternode.prevout.ToStringShort(), nHash.ToString());
  
          if(AddPaymentVote(vote)){
              vote.Relay(connman);
              masternodeSync.BumpAssetLastTime("MASTERNODEPAYMENTVOTE");
          }
      }
  }
  
  bool CMasternodePaymentVote::Sign()
  {
      std::string strError;
      std::string strMessage = vinMasternode.prevout.ToStringShort() +
                  boost::lexical_cast<std::string>(nBlockHeight) +
                  ScriptToAsmStr(payee);
  
      if(!CMessageSigner::SignMessage(strMessage, vchSig, activeMasternode.keyMasternode)) {
          LogPrintf("CMasternodePaymentVote::Sign -- SignMessage() failed\n");
          return false;
      }
  
      if(!CMessageSigner::VerifyMessage(activeMasternode.pubKeyMasternode, vchSig, strMessage, strError)) {
          LogPrintf("CMasternodePaymentVote::Sign -- VerifyMessage() failed, error: %s\n", strError);
          return false;
      }
  
      return true;
  }
  
  bool CMasternodePayments::GetBlockPayee(int nBlockHeight, CScript& payee)
  {
      if(mapMasternodeBlocks.count(nBlockHeight)){
          return mapMasternodeBlocks[nBlockHeight].GetBestPayee(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 blocks of votes
  bool CMasternodePayments::IsScheduled(CMasternode& mn, int nNotBlockHeight)
  {
      LOCK(cs_mapMasternodeBlocks);
  
      if(!masternodeSync.IsMasternodeListSynced()) return false;
  
      CScript mnpayee;
      mnpayee = GetScriptForDestination(mn.pubKeyCollateralAddress.GetID());
  
      CScript payee;
      for(int64_t h = nCachedBlockHeight; h <= nCachedBlockHeight + 8; h++){
          if(h == nNotBlockHeight) continue;
          if(mapMasternodeBlocks.count(h) && mapMasternodeBlocks[h].GetBestPayee(payee) && mnpayee == payee) {
              return true;
          }
      }
  
      return false;
  }
  
  bool CMasternodePayments::AddPaymentVote(const CMasternodePaymentVote& vote)
  {
      uint256 blockHash = uint256();
      if(!GetBlockHash(blockHash, vote.nBlockHeight - 101)) return false;
  
      if(HasVerifiedPaymentVote(vote.GetHash())) return false;
  
      LOCK2(cs_mapMasternodeBlocks, cs_mapMasternodePaymentVotes);
  
      mapMasternodePaymentVotes[vote.GetHash()] = vote;
  
      if(!mapMasternodeBlocks.count(vote.nBlockHeight)) {
         CMasternodeBlockPayees blockPayees(vote.nBlockHeight);
         mapMasternodeBlocks[vote.nBlockHeight] = blockPayees;
      }
  
      mapMasternodeBlocks[vote.nBlockHeight].AddPayee(vote);
  
      return true;
  }
  
  bool CMasternodePayments::HasVerifiedPaymentVote(uint256 hashIn)
  {
      LOCK(cs_mapMasternodePaymentVotes);
      std::map<uint256, CMasternodePaymentVote>::iterator it = mapMasternodePaymentVotes.find(hashIn);
      return it != mapMasternodePaymentVotes.end() && it->second.IsVerified();
  }
  
  void CMasternodeBlockPayees::AddPayee(const CMasternodePaymentVote& vote)
  {
      LOCK(cs_vecPayees);
  
      BOOST_FOREACH(CMasternodePayee& payee, vecPayees) {
          if (payee.GetPayee() == vote.payee) {
              payee.AddVoteHash(vote.GetHash());
              return;
          }
      }
      CMasternodePayee payeeNew(vote.payee, vote.GetHash());
      vecPayees.push_back(payeeNew);
  }
  
  bool CMasternodeBlockPayees::GetBestPayee(CScript& payeeRet)
  {
      LOCK(cs_vecPayees);
  
      if(!vecPayees.size()) {
          LogPrint("mnpayments", "CMasternodeBlockPayees::GetBestPayee -- ERROR: couldn't find any payee\n");
          return false;
      }
  
      int nVotes = -1;
      BOOST_FOREACH(CMasternodePayee& payee, vecPayees) {
          if (payee.GetVoteCount() > nVotes) {
              payeeRet = payee.GetPayee();
              nVotes = payee.GetVoteCount();
          }
      }
  
      return (nVotes > -1);
  }
  
  bool CMasternodeBlockPayees::HasPayeeWithVotes(const CScript& payeeIn, int nVotesReq)
  {
      LOCK(cs_vecPayees);
  
      BOOST_FOREACH(CMasternodePayee& payee, vecPayees) {
          if (payee.GetVoteCount() >= nVotesReq && payee.GetPayee() == payeeIn) {
              return true;
          }
      }
  
      LogPrint("mnpayments", "CMasternodeBlockPayees::HasPayeeWithVotes -- ERROR: couldn't find any payee with %d+ votes\n", nVotesReq);
      return false;
  }
  
  bool CMasternodeBlockPayees::IsTransactionValid(const CTransaction& txNew)
  {
      LOCK(cs_vecPayees);
  
      int nMaxSignatures = 0;
      std::string strPayeesPossible = "";
  
      CAmount nMasternodePayment = GetMasternodePayment(nBlockHeight, txNew.GetValueOut());
  
      //require at least MNPAYMENTS_SIGNATURES_REQUIRED signatures
  
      BOOST_FOREACH(CMasternodePayee& payee, vecPayees) {
          if (payee.GetVoteCount() >= nMaxSignatures) {
              nMaxSignatures = payee.GetVoteCount();
          }
      }
  
      // if we don't have at least MNPAYMENTS_SIGNATURES_REQUIRED signatures on a payee, approve whichever is the longest chain
      if(nMaxSignatures < MNPAYMENTS_SIGNATURES_REQUIRED) return true;
  
      BOOST_FOREACH(CMasternodePayee& payee, vecPayees) {
          if (payee.GetVoteCount() >= MNPAYMENTS_SIGNATURES_REQUIRED) {
              BOOST_FOREACH(CTxOut txout, txNew.vout) {
                  if (payee.GetPayee() == txout.scriptPubKey && nMasternodePayment == txout.nValue) {
                      LogPrint("mnpayments", "CMasternodeBlockPayees::IsTransactionValid -- Found required payment\n");
                      return true;
                  }
              }
  
              CTxDestination address1;
              ExtractDestination(payee.GetPayee(), address1);
              CBitcoinAddress address2(address1);
  
              if(strPayeesPossible == "") {
                  strPayeesPossible = address2.ToString();
              } else {
                  strPayeesPossible += "," + address2.ToString();
              }
          }
      }
  
      LogPrintf("CMasternodeBlockPayees::IsTransactionValid -- ERROR: Missing required payment, possible payees: '%s', amount: %f TOUR\n", strPayeesPossible, (float)nMasternodePayment/COIN);
      return false;
  }
  
  std::string CMasternodeBlockPayees::GetRequiredPaymentsString()
  {
      LOCK(cs_vecPayees);
  
      std::string strRequiredPayments = "Unknown";
  
      BOOST_FOREACH(CMasternodePayee& payee, vecPayees)
      {
          CTxDestination address1;
          ExtractDestination(payee.GetPayee(), address1);
          CBitcoinAddress address2(address1);
  
          if (strRequiredPayments != "Unknown") {
              strRequiredPayments += ", " + address2.ToString() + ":" + boost::lexical_cast<std::string>(payee.GetVoteCount());
          } else {
              strRequiredPayments = address2.ToString() + ":" + boost::lexical_cast<std::string>(payee.GetVoteCount());
          }
      }
  
      return strRequiredPayments;
  }
  
  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::CheckAndRemove()
  {
      if(!masternodeSync.IsBlockchainSynced()) return;
  
      LOCK2(cs_mapMasternodeBlocks, cs_mapMasternodePaymentVotes);
  
      int nLimit = GetStorageLimit();
  
      std::map<uint256, CMasternodePaymentVote>::iterator it = mapMasternodePaymentVotes.begin();
      while(it != mapMasternodePaymentVotes.end()) {
          CMasternodePaymentVote vote = (*it).second;
  
          if(nCachedBlockHeight - vote.nBlockHeight > nLimit) {
              LogPrint("mnpayments", "CMasternodePayments::CheckAndRemove -- Removing old Masternode payment: nBlockHeight=%d\n", vote.nBlockHeight);
              mapMasternodePaymentVotes.erase(it++);
              mapMasternodeBlocks.erase(vote.nBlockHeight);
          } else {
              ++it;
          }
      }
      LogPrintf("CMasternodePayments::CheckAndRemove -- %s\n", ToString());
  }
  
  bool CMasternodePaymentVote::IsValid(CNode* pnode, int nValidationHeight, std::string& strError, CConnman& connman)
  {
      masternode_info_t mnInfo;
  
      if(!mnodeman.GetMasternodeInfo(vinMasternode.prevout, mnInfo)) {
          strError = strprintf("Unknown Masternode: prevout=%s", vinMasternode.prevout.ToStringShort());
          // Only ask if we are already synced and still have no idea about that Masternode
          if(masternodeSync.IsMasternodeListSynced()) {
              mnodeman.AskForMN(pnode, vinMasternode.prevout, connman);
          }
  
          return false;
      }
  
      int nMinRequiredProtocol;
      if(nBlockHeight >= nValidationHeight) {
          // new votes must comply SPORK_10_MASTERNODE_PAY_UPDATED_NODES rules
          nMinRequiredProtocol = mnpayments.GetMinMasternodePaymentsProto();
      } else {
          // allow non-updated masternodes for old blocks
          nMinRequiredProtocol = MIN_MASTERNODE_PAYMENT_PROTO_VERSION_1;
      }
  
      if(mnInfo.nProtocolVersion < nMinRequiredProtocol) {
          strError = strprintf("Masternode protocol is too old: nProtocolVersion=%d, nMinRequiredProtocol=%d", mnInfo.nProtocolVersion, nMinRequiredProtocol);
          return false;
      }
  
      // Only masternodes should try to check masternode rank for old votes - they need to pick the right winner for future blocks.
      // Regular clients (miners included) need to verify masternode rank for future block votes only.
      if(!fMasterNode && nBlockHeight < nValidationHeight) return true;
  
      int nRank;
  
      if(!mnodeman.GetMasternodeRank(vinMasternode.prevout, nRank, nBlockHeight - 101, nMinRequiredProtocol)) {
          LogPrint("mnpayments", "CMasternodePaymentVote::IsValid -- Can't calculate rank for masternode %s\n",
                      vinMasternode.prevout.ToStringShort());
          return false;
      }
  
      if(nRank > 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 in normal mode, debug mode should print though
          strError = strprintf("Masternode is not in the top %d (%d)", MNPAYMENTS_SIGNATURES_TOTAL, nRank);
          // Only ban for new mnw which is out of bounds, for old mnw MN list itself might be way too much off
          if(nRank > MNPAYMENTS_SIGNATURES_TOTAL*2 && nBlockHeight > nValidationHeight) {
              strError = strprintf("Masternode is not in the top %d (%d)", MNPAYMENTS_SIGNATURES_TOTAL*2, nRank);
              LogPrintf("CMasternodePaymentVote::IsValid -- Error: %s\n", strError);
              Misbehaving(pnode->GetId(), 20);
          }
          // Still invalid however
          return false;
      }
  
      return true;
  }
  
  bool CMasternodePayments::ProcessBlock(int nBlockHeight, CConnman& connman)
  {
      // DETERMINE IF WE SHOULD BE VOTING FOR THE NEXT PAYEE
  
      if(fLiteMode || !fMasterNode) return false;
  
      // We have little chances to pick the right winner if winners list is out of sync
      // but we have no choice, so we'll try. However it doesn't make sense to even try to do so
      // if we have not enough data about masternodes.
      if(!masternodeSync.IsMasternodeListSynced()) return false;
  
      int nRank;
  
      if (!mnodeman.GetMasternodeRank(activeMasternode.outpoint, nRank, nBlockHeight - 101, GetMinMasternodePaymentsProto())) {
          LogPrint("mnpayments", "CMasternodePayments::ProcessBlock -- Unknown Masternode\n");
          return false;
      }
  
      if (nRank > MNPAYMENTS_SIGNATURES_TOTAL) {
          LogPrint("mnpayments", "CMasternodePayments::ProcessBlock -- Masternode not in the top %d (%d)\n", MNPAYMENTS_SIGNATURES_TOTAL, nRank);
          return false;
      }
  
  
      // LOCATE THE NEXT MASTERNODE WHICH SHOULD BE PAID
  
      LogPrintf("CMasternodePayments::ProcessBlock -- Start: nBlockHeight=%d, masternode=%s\n", nBlockHeight, activeMasternode.outpoint.ToStringShort());
  
      // 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;
      masternode_info_t mnInfo;
  
      if (!mnodeman.GetNextMasternodeInQueueForPayment(nBlockHeight, true, nCount, mnInfo)) {
          LogPrintf("CMasternodePayments::ProcessBlock -- ERROR: Failed to find masternode to pay\n");
          return false;
      }
  
      LogPrintf("CMasternodePayments::ProcessBlock -- Masternode found by GetNextMasternodeInQueueForPayment(): %s\n", mnInfo.vin.prevout.ToStringShort());
  
  
      CScript payee = GetScriptForDestination(mnInfo.pubKeyCollateralAddress.GetID());
  
      CMasternodePaymentVote voteNew(activeMasternode.outpoint, nBlockHeight, payee);
  
      CTxDestination address1;
      ExtractDestination(payee, address1);
      CBitcoinAddress address2(address1);
  
      LogPrintf("CMasternodePayments::ProcessBlock -- vote: payee=%s, nBlockHeight=%d\n", address2.ToString(), nBlockHeight);
  
      // SIGN MESSAGE TO NETWORK WITH OUR MASTERNODE KEYS
  
      LogPrintf("CMasternodePayments::ProcessBlock -- Signing vote\n");
      if (voteNew.Sign()) {
          LogPrintf("CMasternodePayments::ProcessBlock -- AddPaymentVote()\n");
  
          if (AddPaymentVote(voteNew)) {
              voteNew.Relay(connman);
              return true;
          }
      }
  
      return false;
  }
  
  void CMasternodePayments::CheckPreviousBlockVotes(int nPrevBlockHeight)
  {
      if (!masternodeSync.IsWinnersListSynced()) return;
  
      std::string debugStr;
  
      debugStr += strprintf("CMasternodePayments::CheckPreviousBlockVotes -- nPrevBlockHeight=%d, expected voting MNs:\n", nPrevBlockHeight);
  
      CMasternodeMan::rank_pair_vec_t mns;
      if (!mnodeman.GetMasternodeRanks(mns, nPrevBlockHeight - 101, GetMinMasternodePaymentsProto())) {
          debugStr += "CMasternodePayments::CheckPreviousBlockVotes -- GetMasternodeRanks failed\n";
          LogPrint("mnpayments", "%s", debugStr);
          return;
      }
  
      LOCK2(cs_mapMasternodeBlocks, cs_mapMasternodePaymentVotes);
  
      for (int i = 0; i < MNPAYMENTS_SIGNATURES_TOTAL && i < (int)mns.size(); i++) {
          auto mn = mns[i];
          CScript payee;
          bool found = false;
  
          if (mapMasternodeBlocks.count(nPrevBlockHeight)) {
              for (auto &p : mapMasternodeBlocks[nPrevBlockHeight].vecPayees) {
                  for (auto &voteHash : p.GetVoteHashes()) {
                      if (!mapMasternodePaymentVotes.count(voteHash)) {
                          debugStr += strprintf("CMasternodePayments::CheckPreviousBlockVotes --   could not find vote %s\n",
                                                voteHash.ToString());
                          continue;
                      }
                      auto vote = mapMasternodePaymentVotes[voteHash];
                      if (vote.vinMasternode.prevout == mn.second.vin.prevout) {
                          payee = vote.payee;
                          found = true;
                          break;
                      }
                  }
              }
          }
  
          if (!found) {
              debugStr += strprintf("CMasternodePayments::CheckPreviousBlockVotes --   %s - no vote received\n",
                                    mn.second.vin.prevout.ToStringShort());
              mapMasternodesDidNotVote[mn.second.vin.prevout]++;
              continue;
          }
  
          CTxDestination address1;
          ExtractDestination(payee, address1);
          CBitcoinAddress address2(address1);
  
          debugStr += strprintf("CMasternodePayments::CheckPreviousBlockVotes --   %s - voted for %s\n",
                                mn.second.vin.prevout.ToStringShort(), address2.ToString());
      }
      debugStr += "CMasternodePayments::CheckPreviousBlockVotes -- Masternodes which missed a vote in the past:\n";
      for (auto it : mapMasternodesDidNotVote) {
          debugStr += strprintf("CMasternodePayments::CheckPreviousBlockVotes --   %s: %d\n", it.first.ToStringShort(), it.second);
      }
  
      LogPrint("mnpayments", "%s", debugStr);
  }
  
  void CMasternodePaymentVote::Relay(CConnman& connman)
  {
      // Do not relay until fully synced
      if(!masternodeSync.IsSynced()) {
          LogPrint("mnpayments", "CMasternodePayments::Relay -- won't relay until fully synced\n");
          return;
      }
  
      CInv inv(MSG_MASTERNODE_PAYMENT_VOTE, GetHash());
      connman.RelayInv(inv);
  }
  
  bool CMasternodePaymentVote::CheckSignature(const CPubKey& pubKeyMasternode, int nValidationHeight, int &nDos)
  {
      // do not ban by default
      nDos = 0;
  
      std::string strMessage = vinMasternode.prevout.ToStringShort() +
                  boost::lexical_cast<std::string>(nBlockHeight) +
                  ScriptToAsmStr(payee);
  
      std::string strError = "";
      if (!CMessageSigner::VerifyMessage(pubKeyMasternode, vchSig, strMessage, strError)) {
          // Only ban for future block vote when we are already synced.
          // Otherwise it could be the case when MN which signed this vote is using another key now
          // and we have no idea about the old one.
          if(masternodeSync.IsMasternodeListSynced() && nBlockHeight > nValidationHeight) {
              nDos = 20;
          }
          return error("CMasternodePaymentVote::CheckSignature -- Got bad Masternode payment signature, masternode=%s, error: %s", vinMasternode.prevout.ToStringShort().c_str(), strError);
      }
  
      return true;
  }
  
  std::string CMasternodePaymentVote::ToString() const
  {
      std::ostringstream info;
  
      info << vinMasternode.prevout.ToStringShort() <<
              ", " << nBlockHeight <<
              ", " << ScriptToAsmStr(payee) <<
              ", " << (int)vchSig.size();
  
      return info.str();
  }
  
  // Send only votes for future blocks, node should request every other missing payment block individually
  void CMasternodePayments::Sync(CNode* pnode, CConnman& connman)
  {
      LOCK(cs_mapMasternodeBlocks);
  
      if(!masternodeSync.IsWinnersListSynced()) return;
  
      int nInvCount = 0;
  
      for(int h = nCachedBlockHeight; h < nCachedBlockHeight + 20; h++) {
          if(mapMasternodeBlocks.count(h)) {
              BOOST_FOREACH(CMasternodePayee& payee, mapMasternodeBlocks[h].vecPayees) {
                  std::vector<uint256> vecVoteHashes = payee.GetVoteHashes();
                  BOOST_FOREACH(uint256& hash, vecVoteHashes) {
                      if(!HasVerifiedPaymentVote(hash)) continue;
                      pnode->PushInventory(CInv(MSG_MASTERNODE_PAYMENT_VOTE, hash));
                      nInvCount++;
                  }
              }
          }
      }
  
      LogPrintf("CMasternodePayments::Sync -- Sent %d votes to peer %d\n", nInvCount, pnode->id);
      connman.PushMessage(pnode, NetMsgType::SYNCSTATUSCOUNT, MASTERNODE_SYNC_MNW, nInvCount);
  }
  
  // Request low data/unknown payment blocks in batches directly from some node instead of/after preliminary Sync.
  void CMasternodePayments::RequestLowDataPaymentBlocks(CNode* pnode, CConnman& connman)
  {
      if(!masternodeSync.IsMasternodeListSynced()) return;
  
      LOCK2(cs_main, cs_mapMasternodeBlocks);
  
      std::vector<CInv> vToFetch;
      int nLimit = GetStorageLimit();
  
      const CBlockIndex *pindex = chainActive.Tip();
  
      while(nCachedBlockHeight - pindex->nHeight < nLimit) {
          if(!mapMasternodeBlocks.count(pindex->nHeight)) {
              // We have no idea about this block height, let's ask
              vToFetch.push_back(CInv(MSG_MASTERNODE_PAYMENT_BLOCK, pindex->GetBlockHash()));
              // We should not violate GETDATA rules
              if(vToFetch.size() == MAX_INV_SZ) {
                  LogPrintf("CMasternodePayments::SyncLowDataPaymentBlocks -- asking peer %d for %d blocks\n", pnode->id, MAX_INV_SZ);
                  connman.PushMessage(pnode, NetMsgType::GETDATA, vToFetch);
                  // Start filling new batch
                  vToFetch.clear();
              }
          }
          if(!pindex->pprev) break;
          pindex = pindex->pprev;
      }
  
      std::map<int, CMasternodeBlockPayees>::iterator it = mapMasternodeBlocks.begin();
  
      while(it != mapMasternodeBlocks.end()) {
          int nTotalVotes = 0;
          bool fFound = false;
          BOOST_FOREACH(CMasternodePayee& payee, it->second.vecPayees) {
              if(payee.GetVoteCount() >= MNPAYMENTS_SIGNATURES_REQUIRED) {
                  fFound = true;
                  break;
              }
              nTotalVotes += payee.GetVoteCount();
          }
          // A clear winner (MNPAYMENTS_SIGNATURES_REQUIRED+ votes) was found
          // or no clear winner was found but there are at least avg number of votes
          if(fFound || nTotalVotes >= (MNPAYMENTS_SIGNATURES_TOTAL + MNPAYMENTS_SIGNATURES_REQUIRED)/2) {
              // so just move to the next block
              ++it;
              continue;
          }
          // DEBUG
          DBG (
              // Let's see why this failed
              BOOST_FOREACH(CMasternodePayee& payee, it->second.vecPayees) {
                  CTxDestination address1;
                  ExtractDestination(payee.GetPayee(), address1);
                  CBitcoinAddress address2(address1);
                  printf("payee %s votes %d\n", address2.ToString().c_str(), payee.GetVoteCount());
              }
              printf("block %d votes total %d\n", it->first, nTotalVotes);
          )
          // END DEBUG
          // Low data block found, let's try to sync it
          uint256 hash;
          if(GetBlockHash(hash, it->first)) {
              vToFetch.push_back(CInv(MSG_MASTERNODE_PAYMENT_BLOCK, hash));
          }
          // We should not violate GETDATA rules
          if(vToFetch.size() == MAX_INV_SZ) {
              LogPrintf("CMasternodePayments::SyncLowDataPaymentBlocks -- asking peer %d for %d payment blocks\n", pnode->id, MAX_INV_SZ);
              connman.PushMessage(pnode, NetMsgType::GETDATA, vToFetch);
              // Start filling new batch
              vToFetch.clear();
          }
          ++it;
      }
      // Ask for the rest of it
      if(!vToFetch.empty()) {
          LogPrintf("CMasternodePayments::SyncLowDataPaymentBlocks -- asking peer %d for %d payment blocks\n", pnode->id, vToFetch.size());
          connman.PushMessage(pnode, NetMsgType::GETDATA, vToFetch);
      }
  }
  
  std::string CMasternodePayments::ToString() const
  {
      std::ostringstream info;
  
      info << "Votes: " << (int)mapMasternodePaymentVotes.size() <<
              ", Blocks: " << (int)mapMasternodeBlocks.size();
  
      return info.str();
  }
  
  bool CMasternodePayments::IsEnoughData()
  {
      float nAverageVotes = (MNPAYMENTS_SIGNATURES_TOTAL + MNPAYMENTS_SIGNATURES_REQUIRED) / 2;
      int nStorageLimit = GetStorageLimit();
      return GetBlockCount() > nStorageLimit && GetVoteCount() > nStorageLimit * nAverageVotes;
  }
  
  int CMasternodePayments::GetStorageLimit()
  {
      return std::max(int(mnodeman.size() * nStorageCoeff), nMinBlocksToStore);
  }
  
  void CMasternodePayments::UpdatedBlockTip(const CBlockIndex *pindex, CConnman& connman)
  {
      if(!pindex) return;
  
      nCachedBlockHeight = pindex->nHeight;
      LogPrint("mnpayments", "CMasternodePayments::UpdatedBlockTip -- nCachedBlockHeight=%d\n", nCachedBlockHeight);
  
      int nFutureBlock = nCachedBlockHeight + 10;
  
      CheckPreviousBlockVotes(nFutureBlock - 1);
      ProcessBlock(nFutureBlock, connman);
  }
  