text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2015 The Bitcoin Core developers
  // Copyright (c) 2014-2017 The Crowdcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "miner.h"
  
  #include "amount.h"
  #include "chain.h"
  #include "chainparams.h"
  #include "coins.h"
  #include "consensus/consensus.h"
  #include "consensus/merkle.h"
  #include "consensus/validation.h"
  #include "hash.h"
  #include "validation.h"
  #include "net.h"
  #include "policy/policy.h"
  #include "pow.h"
  #include "primitives/transaction.h"
  #include "script/standard.h"
  #include "timedata.h"
  #include "txmempool.h"
  #include "util.h"
  #include "utilmoneystr.h"
  #include "masternode-payments.h"
  #include "masternode-sync.h"
  #include "validationinterface.h"
  
  #include <boost/thread.hpp>
  #include <boost/tuple/tuple.hpp>
  #include <queue>
  
  using namespace std;
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // DashMiner
  //
  
  //
  // 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.
  
  uint64_t nLastBlockTx = 0;
  uint64_t nLastBlockSize = 0;
  
  class ScoreCompare
  {
  public:
      ScoreCompare() {}
  
      bool operator()(const CTxMemPool::txiter a, const CTxMemPool::txiter b)
      {
          return CompareTxMemPoolEntryByScore()(*b,*a); // Convert to less than
      }
  };
  
  int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
  {
      int64_t nOldTime = pblock->nTime;
      int64_t nNewTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
  
      if (nOldTime < nNewTime)
          pblock->nTime = nNewTime;
  
      // Updating time can change work required on testnet:
      if (consensusParams.fPowAllowMinDifficultyBlocks)
          pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams);
  
      return nNewTime - nOldTime;
  }
  
  CBlockTemplate* CreateNewBlock(const CChainParams& chainparams, const CScript& scriptPubKeyIn)
  {
      // Create new block
      std::unique_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
      if(!pblocktemplate.get())
          return NULL;
      CBlock *pblock = &pblocktemplate->block; // pointer for convenience
  
      // Create coinbase tx
      CMutableTransaction txNew;
      txNew.vin.resize(1);
      txNew.vin[0].prevout.SetNull();
      txNew.vout.resize(1);
      txNew.vout[0].scriptPubKey = scriptPubKeyIn;
  
      // Largest block you're willing to create:
      unsigned int nBlockMaxSize = GetArg("-blockmaxsize", DEFAULT_BLOCK_MAX_SIZE);
      // Limit to between 1K and MAX_BLOCK_SIZE-1K for sanity:
      nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MaxBlockSize(fDIP0001ActiveAtTip)-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
      CTxMemPool::setEntries inBlock;
      CTxMemPool::setEntries waitSet;
  
      // This vector will be sorted into a priority queue:
      vector<TxCoinAgePriority> vecPriority;
      TxCoinAgePriorityCompare pricomparer;
      std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash> waitPriMap;
      typedef std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash>::iterator waitPriIter;
      double actualPriority = -1;
  
      std::priority_queue<CTxMemPool::txiter, std::vector<CTxMemPool::txiter>, ScoreCompare> clearedTxs;
      bool fPrintPriority = GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
      uint64_t nBlockSize = 1000;
      uint64_t nBlockTx = 0;
      unsigned int nBlockSigOps = 100;
      int lastFewTxs = 0;
      CAmount nFees = 0;
  
      {
          LOCK(cs_main);
  
          CBlockIndex* pindexPrev = chainActive.Tip();
          const int nHeight = pindexPrev->nHeight + 1;
          pblock->nTime = GetAdjustedTime();
          const int64_t nMedianTimePast = pindexPrev->GetMedianTimePast();
  
          // Add our coinbase tx as first transaction
          pblock->vtx.push_back(txNew);
          pblocktemplate->vTxFees.push_back(-1); // updated at end
          pblocktemplate->vTxSigOps.push_back(-1); // updated at end
          pblock->nVersion = ComputeBlockVersion(pindexPrev, chainparams.GetConsensus());
          // -regtest only: allow overriding block.nVersion with
          // -blockversion=N to test forking scenarios
          if (chainparams.MineBlocksOnDemand())
              pblock->nVersion = GetArg("-blockversion", pblock->nVersion);
  
          int64_t nLockTimeCutoff = (STANDARD_LOCKTIME_VERIFY_FLAGS & LOCKTIME_MEDIAN_TIME_PAST)
                                  ? nMedianTimePast
                                  : pblock->GetBlockTime();
  
          {
              LOCK(mempool.cs);
  
              bool fPriorityBlock = nBlockPrioritySize > 0;
              if (fPriorityBlock) {
                  vecPriority.reserve(mempool.mapTx.size());
                  for (CTxMemPool::indexed_transaction_set::iterator mi = mempool.mapTx.begin();
                       mi != mempool.mapTx.end(); ++mi)
                  {
                      double dPriority = mi->GetPriority(nHeight);
                      CAmount dummy;
                      mempool.ApplyDeltas(mi->GetTx().GetHash(), dPriority, dummy);
                      vecPriority.push_back(TxCoinAgePriority(dPriority, mi));
                  }
                  std::make_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
              }
  
              CTxMemPool::indexed_transaction_set::nth_index<3>::type::iterator mi = mempool.mapTx.get<3>().begin();
              CTxMemPool::txiter iter;
  
              while (mi != mempool.mapTx.get<3>().end() || !clearedTxs.empty())
              {
                  bool priorityTx = false;
                  if (fPriorityBlock && !vecPriority.empty()) { // add a tx from priority queue to fill the blockprioritysize
                      priorityTx = true;
                      iter = vecPriority.front().second;
                      actualPriority = vecPriority.front().first;
                      std::pop_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
                      vecPriority.pop_back();
                  }
                  else if (clearedTxs.empty()) { // add tx with next highest score
                      iter = mempool.mapTx.project<0>(mi);
                      mi++;
                  }
                  else {  // try to add a previously postponed child tx
                      iter = clearedTxs.top();
                      clearedTxs.pop();
                  }
  
                  if (inBlock.count(iter))
                      continue; // could have been added to the priorityBlock
  
                  const CTransaction& tx = iter->GetTx();
  
                  bool fOrphan = false;
                  BOOST_FOREACH(CTxMemPool::txiter parent, mempool.GetMemPoolParents(iter))
                  {
                      if (!inBlock.count(parent)) {
                          fOrphan = true;
                          break;
                      }
                  }
                  if (fOrphan) {
                      if (priorityTx)
                          waitPriMap.insert(std::make_pair(iter,actualPriority));
                      else
                          waitSet.insert(iter);
                      continue;
                  }
  
                  unsigned int nTxSize = iter->GetTxSize();
                  if (fPriorityBlock &&
                      (nBlockSize + nTxSize >= nBlockPrioritySize || !AllowFree(actualPriority))) {
                      fPriorityBlock = false;
                      waitPriMap.clear();
                  }
                  if (!priorityTx &&
                      (iter->GetModifiedFee() < ::minRelayTxFee.GetFee(nTxSize) && nBlockSize >= nBlockMinSize)) {
                      break;
                  }
                  if (nBlockSize + nTxSize >= nBlockMaxSize) {
                      if (nBlockSize >  nBlockMaxSize - 100 || lastFewTxs > 50) {
                          break;
                      }
                      // Once we're within 1000 bytes of a full block, only look at 50 more txs
                      // to try to fill the remaining space.
                      if (nBlockSize > nBlockMaxSize - 1000) {
                          lastFewTxs++;
                      }
                      continue;
                  }
  
                  if (!IsFinalTx(tx, nHeight, nLockTimeCutoff))
                      continue;
  
                  unsigned int nTxSigOps = iter->GetSigOpCount();
                  unsigned int nMaxBlockSigOps = MaxBlockSigOps(fDIP0001ActiveAtTip);
                  if (nBlockSigOps + nTxSigOps >= nMaxBlockSigOps) {
                      if (nBlockSigOps > nMaxBlockSigOps - 2) {
                          break;
                      }
                      continue;
                  }
  
                  CAmount nTxFees = iter->GetFee();
                  // Added
                  pblock->vtx.push_back(tx);
                  pblocktemplate->vTxFees.push_back(nTxFees);
                  pblocktemplate->vTxSigOps.push_back(nTxSigOps);
                  nBlockSize += nTxSize;
                  ++nBlockTx;
                  nBlockSigOps += nTxSigOps;
                  nFees += nTxFees;
  
                  if (fPrintPriority)
                  {
                      double dPriority = iter->GetPriority(nHeight);
                      CAmount dummy;
                      mempool.ApplyDeltas(tx.GetHash(), dPriority, dummy);
                      LogPrintf("priority %.1f fee %s txid %s\n",
                                dPriority , CFeeRate(iter->GetModifiedFee(), nTxSize).ToString(), tx.GetHash().ToString());
                  }
  
                  inBlock.insert(iter);
  
                  // Add transactions that depend on this one to the priority queue
                  BOOST_FOREACH(CTxMemPool::txiter child, mempool.GetMemPoolChildren(iter))
                  {
                      if (fPriorityBlock) {
                          waitPriIter wpiter = waitPriMap.find(child);
                          if (wpiter != waitPriMap.end()) {
                              vecPriority.push_back(TxCoinAgePriority(wpiter->second,child));
                              std::push_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
                              waitPriMap.erase(wpiter);
                          }
                      }
                      else {
                          if (waitSet.count(child)) {
                              clearedTxs.push(child);
                              waitSet.erase(child);
                          }
                      }
                  }
              }
  
          }
  
          // NOTE: unlike in bitcoin, we need to pass PREVIOUS block height here
          CAmount blockReward = nFees + GetBlockSubsidy(pindexPrev->nBits, pindexPrev->nHeight, Params().GetConsensus());
  
          // Compute regular coinbase transaction.
          txNew.vout[0].nValue = blockReward;
          txNew.vin[0].scriptSig = CScript() << nHeight << OP_0;
  
          // Update coinbase transaction with additional info about masternode and governance payments,
          // get some info back to pass to getblocktemplate
          FillBlockPayments(txNew, nHeight, blockReward, pblock->txoutMasternode, pblock->voutSuperblock);
          // LogPrintf("CreateNewBlock -- nBlockHeight %d blockReward %lld txoutMasternode %s txNew %s",
          //             nHeight, blockReward, pblock->txoutMasternode.ToString(), txNew.ToString());
  
          nLastBlockTx = nBlockTx;
          nLastBlockSize = nBlockSize;
          LogPrintf("CreateNewBlock(): total size %u txs: %u fees: %ld sigops %d\n", nBlockSize, nBlockTx, nFees, nBlockSigOps);
  
          // Update block coinbase
          pblock->vtx[0] = txNew;
          pblocktemplate->vTxFees[0] = -nFees;
  
          // Fill in header
          pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
          UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
          pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock, chainparams.GetConsensus());
          pblock->nNonce         = 0;
          pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
  
          CValidationState state;
          if (!TestBlockValidity(state, chainparams, *pblock, pindexPrev, false, false)) {
              throw std::runtime_error(strprintf("%s: TestBlockValidity failed: %s", __func__, FormatStateMessage(state)));
          }
      }
  
      return pblocktemplate.release();
  }
  
  void IncrementExtraNonce(CBlock* pblock, const 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);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  //
  // Internal miner
  //
  
  // ***TODO*** ScanHash is not yet used in Crowdcoin
  //
  // ScanHash scans nonces looking for a hash with at least some zero bits.
  // The nonce is usually preserved between calls, but periodically or if the
  // nonce is 0xffff0000 or above, the block is rebuilt and nNonce starts over at
  // zero.
  //
  //bool static ScanHash(const CBlockHeader *pblock, uint32_t& nNonce, uint256 *phash)
  //{
  //    // Write the first 76 bytes of the block header to a double-SHA256 state.
  //    CHash256 hasher;
  //    CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
  //    ss << *pblock;
  //    assert(ss.size() == 80);
  //    hasher.Write((unsigned char*)&ss[0], 76);
  
  //    while (true) {
  //        nNonce++;
  
  //        // Write the last 4 bytes of the block header (the nonce) to a copy of
  //        // the double-SHA256 state, and compute the result.
  //        CHash256(hasher).Write((unsigned char*)&nNonce, 4).Finalize((unsigned char*)phash);
  
  //        // Return the nonce if the hash has at least some zero bits,
  //        // caller will check if it has enough to reach the target
  //        if (((uint16_t*)phash)[15] == 0)
  //            return true;
  
  //        // If nothing found after trying for a while, return -1
  //        if ((nNonce & 0xfff) == 0)
  //            return false;
  //    }
  //}
  
  static bool ProcessBlockFound(const CBlock* pblock, const CChainParams& chainparams)
  {
      LogPrintf("%s\n", pblock->ToString());
      LogPrintf("generated %s\n", FormatMoney(pblock->vtx[0].vout[0].nValue));
  
      // Found a solution
      {
          LOCK(cs_main);
          if (pblock->hashPrevBlock != chainActive.Tip()->GetBlockHash())
              return error("ProcessBlockFound -- generated block is stale");
      }
  
      // Inform about the new block
      GetMainSignals().BlockFound(pblock->GetHash());
  
      // Process this block the same as if we had received it from another node
      if (!ProcessNewBlock(chainparams, pblock, true, NULL, NULL))
          return error("ProcessBlockFound -- ProcessNewBlock() failed, block not accepted");
  
      return true;
  }
  
  // ***TODO*** that part changed in bitcoin, we are using a mix with old one here for now
  void static BitcoinMiner(const CChainParams& chainparams, CConnman& connman)
  {
      LogPrintf("DashMiner -- started\n");
      SetThreadPriority(THREAD_PRIORITY_LOWEST);
      RenameThread("dash-miner");
  
      unsigned int nExtraNonce = 0;
  
      boost::shared_ptr<CReserveScript> coinbaseScript;
      GetMainSignals().ScriptForMining(coinbaseScript);
  
      try {
          // Throw an error if no script was provided.  This can happen
          // due to some internal error but also if the keypool is empty.
          // In the latter case, already the pointer is NULL.
          if (!coinbaseScript || coinbaseScript->reserveScript.empty())
              throw std::runtime_error("No coinbase script available (mining requires a wallet)");
  
          while (true) {
              if (chainparams.MiningRequiresPeers()) {
                  // Busy-wait for the network to come online so we don't waste time mining
                  // on an obsolete chain. In regtest mode we expect to fly solo.
                  do {
                      bool fvNodesEmpty = connman.GetNodeCount(CConnman::CONNECTIONS_ALL) == 0;
                      if (!fvNodesEmpty && !IsInitialBlockDownload() && masternodeSync.IsSynced())
                          break;
                      MilliSleep(1000);
                  } while (true);
              }
  
  
              //
              // Create new block
              //
              unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
              CBlockIndex* pindexPrev = chainActive.Tip();
              if(!pindexPrev) break;
  
              std::unique_ptr<CBlockTemplate> pblocktemplate(CreateNewBlock(chainparams, coinbaseScript->reserveScript));
              if (!pblocktemplate.get())
              {
                  LogPrintf("DashMiner -- Keypool ran out, please call keypoolrefill before restarting the mining thread\n");
                  return;
              }
              CBlock *pblock = &pblocktemplate->block;
              IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
  
              LogPrintf("DashMiner -- Running miner with %u transactions in block (%u bytes)\n", pblock->vtx.size(),
                  ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
  
              //
              // Search
              //
              int64_t nStart = GetTime();
              arith_uint256 hashTarget = arith_uint256().SetCompact(pblock->nBits);
              while (true)
              {
                  unsigned int nHashesDone = 0;
  
                  uint256 hash;
                  while (true)
                  {
                      hash = pblock->GetHash();
                      if (UintToArith256(hash) <= hashTarget)
                      {
                          // Found a solution
                          SetThreadPriority(THREAD_PRIORITY_NORMAL);
                          LogPrintf("DashMiner:\n  proof-of-work found\n  hash: %s\n  target: %s\n", hash.GetHex(), hashTarget.GetHex());
                          ProcessBlockFound(pblock, chainparams);
                          SetThreadPriority(THREAD_PRIORITY_LOWEST);
                          coinbaseScript->KeepScript();
  
                          // In regression test mode, stop mining after a block is found. This
                          // allows developers to controllably generate a block on demand.
                          if (chainparams.MineBlocksOnDemand())
                              throw boost::thread_interrupted();
  
                          break;
                      }
                      pblock->nNonce += 1;
                      nHashesDone += 1;
                      if ((pblock->nNonce & 0xFF) == 0)
                          break;
                  }
  
                  // Check for stop or if block needs to be rebuilt
                  boost::this_thread::interruption_point();
                  // Regtest mode doesn't require peers
                  if (connman.GetNodeCount(CConnman::CONNECTIONS_ALL) == 0 && chainparams.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
                  if (UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev) < 0)
                      break; // Recreate the block if the clock has run backwards,
                             // so that we can use the correct time.
                  if (chainparams.GetConsensus().fPowAllowMinDifficultyBlocks)
                  {
                      // Changing pblock->nTime can change work required on testnet:
                      hashTarget.SetCompact(pblock->nBits);
                  }
              }
          }
      }
      catch (const boost::thread_interrupted&)
      {
          LogPrintf("DashMiner -- terminated\n");
          throw;
      }
      catch (const std::runtime_error &e)
      {
          LogPrintf("DashMiner -- runtime error: %s\n", e.what());
          return;
      }
  }
  
  void GenerateBitcoins(bool fGenerate, int nThreads, const CChainParams& chainparams, CConnman& connman)
  {
      static boost::thread_group* minerThreads = NULL;
  
      if (nThreads < 0)
          nThreads = GetNumCores();
  
      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(&BitcoinMiner, boost::cref(chainparams), boost::ref(connman)));
  }
  