/* Copyright (C) 2014 InfiniDB, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; version 2 of
   the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

/*
 * $Id: we_dbrootextenttracker.cpp 3672 2012-03-26 12:31:27Z rdempsey $
 */

#include <unistd.h>
#include <algorithm>
#include <sstream>
#include <boost/scoped_ptr.hpp>

#include "dbrm.h"
#include "batchloader.h"

using namespace std;
using namespace boost;
using namespace BRM;
using namespace oam;
using namespace execplan;

namespace batchloader
{
//------------------------------------------------------------------------------
// ChooseStartLoadPM constructor
//
// Mutex lock not needed in this function as it is only called from main thread
//------------------------------------------------------------------------------
BatchLoader::BatchLoader(uint32_t tableOid, execplan::CalpontSystemCatalog::SCN sessionId,
                         std::vector<uint32_t>& PMs)
{
  fFirstPm = 0;
  fNextIdx = 0;
  fPMs = PMs;
  fSessionId = sessionId;
  fTableOid = tableOid;
  OamCache* oamcache = OamCache::makeOamCache();
  oam::OamCache::PMDbrootsMap_t systemPmDbrootMap = oamcache->getPMToDbrootsMap();
  std::map<int, OamCache::dbRoots>::iterator iter = systemPmDbrootMap->begin();
  // cout << "fPMs size is " << fPMs.size() << endl;
  fPmDbrootMap.reset(new OamCache::PMDbrootsMap_t::element_type());
  fDbrootPMmap.reset(new map<int, int>());

  for (uint32_t i = 0; i < fPMs.size(); i++)
  {
    iter = systemPmDbrootMap->find(fPMs[i]);

    if (iter != systemPmDbrootMap->end())
    {
      fDbRoots.insert(fDbRoots.end(), (iter->second).begin(), (iter->second).end());
      (*fPmDbrootMap)[fPMs[i]] = iter->second;
    }
  }

  // Build dbroot to PM map
  for (iter = fPmDbrootMap->begin(); iter != fPmDbrootMap->end(); iter++)
  {
    for (uint32_t i = 0; i < iter->second.size(); i++)
    {
      (*fDbrootPMmap)[iter->second[i]] = iter->first;
    }
  }
}
//------------------------------------------------------------------------------
// Select the first PM to send the first batch of rows.
/*Look up extent map to decide which dbroot to start
        1. If newly created table, starts from the pm where the abbreviated extent created.
        2. If the abbreviated extent has hwm > 0, and other PMs don't have any extent, start from next PM on
   the list. 2.5If some DBRoots have extents and some don't the DBRoot with the fewest extents or blocks is
   chosen, "unless" the partition 0, segment 0 extent is one of the HWM extents.  In that case the partition
   0, segment 0 extent still takes precedence.
        3. If all PMs have extents, count the number of extents under each dbroot, find the dbroot which has
   the least extents to start
        4. If all dbroots have same number of extents, starts from the dbroot which has least number of blocks
*/
//------------------------------------------------------------------------------
void BatchLoader::selectFirstPM(uint32_t& PMId)
{
  boost::shared_ptr<CalpontSystemCatalog> systemCatalogPtr =
      CalpontSystemCatalog::makeCalpontSystemCatalog(fSessionId);
  // cout << "calling tableName for oid " << fTableOid << endl;
  CalpontSystemCatalog::TableName aTableName = systemCatalogPtr->tableName(fTableOid);

  CalpontSystemCatalog::RIDList ridList;
  ridList = systemCatalogPtr->columnRIDs(aTableName, true);  // exception will be handled in caller program.

  scoped_ptr<DBRM> dbrmp(new DBRM());

  // Build distVec, start from the PM where the table is created. If not in the PM list, 0 will be used.
  uint16_t createdDbroot = 0;
  int rc = 0;
  std::vector<BRM::EmDbRootHWMInfo_v> allInfo(fPMs.size());

  for (unsigned i = 0; i < fPMs.size(); i++)
  {
    rc = dbrmp->getDbRootHWMInfo((ridList[0].objnum), fPMs[i], allInfo[i]);

    if (rc != 0)  //@Bug 4760
      break;
  }

  if (rc != 0)
  {
    ostringstream oss;
    oss << "There is no extent information for table " << aTableName.table;
    throw std::runtime_error(oss.str());
  }

  uint32_t numDbroot = fDbRoots.size();

  if (numDbroot == 0)
  {
    throw std::runtime_error("There are no dbroots found during selectFirstPM");
  }

  uint64_t* rootExtents =
      (uint64_t*)alloca((numDbroot + 1) * sizeof(uint64_t));  // array of number extents for each dbroot

  for (unsigned i = 0; i < fDbRoots.size(); i++)
  {
    uint64_t numExtents;
    dbrmp->getExtentCount_dbroot((ridList[0].objnum), fDbRoots[i], false, numExtents);
    rootExtents[fDbRoots[i]] = numExtents;
  }

  bool startDBRootSet = false;
  uint64_t* rootBlocks = (uint64_t*)alloca(
      (numDbroot + 1) *
      sizeof(uint64_t));  // array of number of blocks for the last partition for each dbroot
  // cout << "allInfo size is " << allInfo.size() << endl;

  //--------------------------------------------------------------------------
  // Load rootBlocks to carry total blocks for each DBRoot
  // Set startDBRootSet if the partition 0 segment 0 extent is empty
  // Set createdDbroot for the DBRoot that carries the partition 0
  //     segment 0 extent (used to set the default PMId)
  //--------------------------------------------------------------------------
  for (unsigned i = 0; i < allInfo.size(); i++)  // All PMs
  {
    BRM::EmDbRootHWMInfo_v emDbRootHWMInfos = allInfo[i];  // one pm

    for (unsigned j = 0; j < emDbRootHWMInfos.size(); j++)
    {
      if (emDbRootHWMInfos[j].totalBlocks == 0)
      {
        // cout << "totalBlocks is 0" << endl;
        continue;
      }

      //------------------------------------------------------------------
      // Ignore partition 0, segment 0 HWM extent if it is disabled
      //------------------------------------------------------------------
      if ((emDbRootHWMInfos[j].partitionNum == 0) && (emDbRootHWMInfos[j].segmentNum == 0) &&
          (emDbRootHWMInfos[j].status != BRM::EXTENTOUTOFSERVICE))
      {
        if (emDbRootHWMInfos[j].localHWM == 0)
        {
          // newly created table
          // cout << " This is newly created table. PM id is " << PMId;
          startDBRootSet = true;
          createdDbroot = emDbRootHWMInfos[j].dbRoot;
          break;
        }
        else
        {
          createdDbroot = emDbRootHWMInfos[j].dbRoot;
          // cout << " and createdDbroot is " << createdDbroot << endl;
          rootBlocks[emDbRootHWMInfos[j].dbRoot] = emDbRootHWMInfos[j].totalBlocks;
        }
      }
      else
      {
        rootBlocks[emDbRootHWMInfos[j].dbRoot] = emDbRootHWMInfos[j].totalBlocks;
      }
    }

    if (startDBRootSet)
      break;
  }

  //--------------------------------------------------------------------------
  // Set the default PMId to the PM with the partition 0 segment 0 extent
  //--------------------------------------------------------------------------
  PMId = 0;

  if (createdDbroot != 0)
  {
    std::map<int, int>::iterator iter = fDbrootPMmap->begin();

    iter = fDbrootPMmap->find(createdDbroot);

    if (iter != fDbrootPMmap->end())
      PMId = iter->second;
  }

  // This will build the batch distribution sequence
  // cout << "Building BatchDistSeqVector with PMId " << PMId << endl;
  buildBatchDistSeqVector(PMId);

  // cout << "startDBRootSet = " << startDBRootSet << endl;
  bool allEqual = true;
  bool allOtherDbrootEmpty = true;

  //--------------------------------------------------------------------------
  // startDBRootSet == false
  // We don't have an empty partition 0, segment 0 extent to load;
  // so evaluate more selection criteria.
  //--------------------------------------------------------------------------
  if (!startDBRootSet)
  {
    std::vector<PMRootInfo> rootsExtentsBlocks;
    std::map<int, OamCache::dbRoots>::iterator iter;

    //----------------------------------------------------------------------
    // Load rootsExtentsBlocks to carry the number of extents and blocks
    // for each DBRoot.
    //----------------------------------------------------------------------
    for (unsigned j = 0; j < fPmDistSeq.size(); j++)
    {
      PMRootInfo aEntry;
      aEntry.PMId = fPmDistSeq[j];
      iter = fPmDbrootMap->find(aEntry.PMId);

      for (unsigned k = 0; k < (iter->second).size(); k++)
      {
        RootExtentsBlocks aRootInfo;
        aRootInfo.DBRoot = (iter->second)[k];
        aRootInfo.numExtents = rootExtents[aRootInfo.DBRoot];
        aRootInfo.numBlocks = rootBlocks[aRootInfo.DBRoot];
        // cout << "aRootInfo DBRoot:numExtents:numBlocks = " <<
        // aRootInfo.DBRoot<<":"<<aRootInfo.numExtents<<":"<<aRootInfo.numBlocks<<endl;
        aEntry.rootInfo.push_back(aRootInfo);
      }

      rootsExtentsBlocks.push_back(aEntry);
    }

    // cout << "rootsExtentsBlocks size is " << rootsExtentsBlocks.size() << " and allOtherDbrootEmpty is " <<
    // allOtherDbrootEmpty<< endl;

    //----------------------------------------------------------------------
    // See if all other DBRoots other than the createdDbroot have 0 extents
    //----------------------------------------------------------------------
    for (unsigned i = 1; i < rootsExtentsBlocks.size(); i++)
    {
      if (!allOtherDbrootEmpty)
        break;

      // cout << "createdDbroot is " << createdDbroot << endl;
      if (i != createdDbroot)
      {
        for (unsigned j = 0; j < rootsExtentsBlocks[i].rootInfo.size(); j++)
        {
          if (rootsExtentsBlocks[i].rootInfo[j].numExtents != 0)
          {
            // cout << "setting allOtherDbrootEmpty to false and i:j = " << i<<":"<<j<<endl;
            // cout << "numExtents = " << rootsExtentsBlocks[i].rootInfo[j].numExtents << endl;
            allOtherDbrootEmpty = false;
            break;
          }
        }
      }
    }

    // cout << "allOtherDbrootEmpty is " << allOtherDbrootEmpty << endl;

    //----------------------------------------------------------------------
    // allOtherDbrootEmpty == true
    // No DBRoots (other than the DBRoot having the partition 0,
    // segment 0 extent) have extents
    //----------------------------------------------------------------------
    if (allOtherDbrootEmpty)
    {
      // find the next PM id on the list
      startDBRootSet = true;
      buildBatchDistSeqVector();

      allEqual = false;
    }
    //----------------------------------------------------------------------
    // allOtherDbrootEmpty == false
    // Some DBRoots (other than the DBRoot having the partition 0,
    // segment 0 extent) have extents.  More evaluation necessary.
    //----------------------------------------------------------------------
    else  // find the dbroot which has the least extents to start
    {
      // cout << "finding least dbroot to start." << endl;
      //------------------------------------------------------------------
      // Select PM with DBRoot having the fewest extents.
      //------------------------------------------------------------------
      uint32_t tmpLeastExtents = rootsExtentsBlocks[0].rootInfo[0].numExtents;
      PMId = rootsExtentsBlocks[0].PMId;  //@Bug 4809.

      for (unsigned j = 1; j < rootsExtentsBlocks[0].rootInfo.size(); j++)
      {
        if (tmpLeastExtents > rootsExtentsBlocks[0].rootInfo[j].numExtents)
          tmpLeastExtents = rootsExtentsBlocks[0].rootInfo[j].numExtents;
      }

      for (unsigned i = 1; i < rootsExtentsBlocks.size(); i++)
      {
        uint32_t leastExtents = rootsExtentsBlocks[i].rootInfo[0].numExtents;

        for (unsigned j = 0; j < rootsExtentsBlocks[i].rootInfo.size(); j++)
        {
          if (leastExtents > rootsExtentsBlocks[i].rootInfo[j].numExtents)
            leastExtents = rootsExtentsBlocks[i].rootInfo[j].numExtents;
        }

        if (leastExtents < tmpLeastExtents)
        {
          tmpLeastExtents = leastExtents;
          PMId = rootsExtentsBlocks[i].PMId;
          allEqual = false;
        }
        else if (leastExtents > tmpLeastExtents)
          allEqual = false;
      }

      // cout << "allEqual is " << allEqual << endl;

      //------------------------------------------------------------------
      // All DBRoots have the same number of extents.
      // Select PM with DBRoot having the fewest number of blocks.
      //------------------------------------------------------------------
      if (allEqual)  // Find the dbroot which has least number of blocks
      {
        // cout << "All PMs have equal # of least extents" << endl;
        uint32_t tmpBloks = rootsExtentsBlocks[0].rootInfo[0].numBlocks;

        PMId = rootsExtentsBlocks[0].PMId;

        // cout << "tmpBloks:PMId = " << tmpBloks <<":"<<PMId<<endl;
        for (unsigned j = 1; j < rootsExtentsBlocks[0].rootInfo.size(); j++)
        {
          if (tmpBloks > rootsExtentsBlocks[0].rootInfo[j].numBlocks)
            tmpBloks = rootsExtentsBlocks[0].rootInfo[j].numBlocks;
        }

        for (unsigned i = 1; i < rootsExtentsBlocks.size(); i++)
        {
          uint32_t leastBlocks = rootsExtentsBlocks[i].rootInfo[0].numBlocks;

          // cout << "leastBlocks = " << leastBlocks << endl;
          for (unsigned j = 0; j < rootsExtentsBlocks[i].rootInfo.size(); j++)
          {
            if (leastBlocks > rootsExtentsBlocks[i].rootInfo[j].numBlocks)
              leastBlocks = rootsExtentsBlocks[i].rootInfo[j].numBlocks;
          }

          if (leastBlocks < tmpBloks)
          {
            tmpBloks = leastBlocks;
            // cout << "tmpBloks changed to " << tmpBloks << endl;
            PMId = rootsExtentsBlocks[i].PMId;
            // cout << "setting allEqual to false now" << endl;
            allEqual = false;
          }
        }
      }
    }
  }
  //--------------------------------------------------------------------------
  // startDBRootSet == true
  // We select the empty partition 0, segment 0 extent to load
  //--------------------------------------------------------------------------
  else
  {
    allEqual = false;
  }

  fFirstPm = PMId;

  if (!allOtherDbrootEmpty || (PMId == 0))
  {
    prepareForSecondPM();
    // cout << "prepareForSecondPM is called. " << endl;
  }

  if ((allEqual && (PMId == 0)) || allOtherDbrootEmpty)
  {
    PMId = selectNextPM();
    fFirstPm = PMId;
    // cout << "PMId is now " << PMId << endl;
  }
}

//------------------------------------------------------------------------------
/*
 * Build the sequence of distribution as a vector.
 */

//------------------------------------------------------------------------------
void BatchLoader::buildBatchDistSeqVector()
{
  fPmDistSeq.clear();
  BlIntVec aDbCntVec(fPMs.size());

  std::map<int, OamCache::dbRoots>::iterator iter = fPmDbrootMap->begin();

  for (uint32_t i = 0; i < fPMs.size(); i++)
  {
    iter = fPmDbrootMap->find(fPMs[i]);

    if ((iter != fPmDbrootMap->end()) && ((iter->second).begin() != (iter->second).end()))
    {
      try
      {
        aDbCntVec[i] = (iter->second).size();
        // cout << "PM - "<<fPMs[i] << " Size = " << aDbCntVec[i] << endl;
      }
      catch (std::exception& exp)
      {
        throw runtime_error(exp.what());
      }
    }
    else
      aDbCntVec[i] = 0;
  }

  int aTotDbRoots = 0;

  for (uint32_t i = 0; i < aDbCntVec.size(); i++)
    aTotDbRoots += aDbCntVec[i];

  int aIdx = 0;

  while (aIdx < aTotDbRoots)
  {
    uint32_t aMax = 0;
    uint32_t aPmId = 0;
    uint32_t aRefIdx = 0;

    for (uint32_t i = 0; i < aDbCntVec.size(); i++)
    {
      if (aDbCntVec[i] > aMax)
      {
        aMax = aDbCntVec[i];
        aPmId = fPMs[i];
        aRefIdx = i;
      }
    }

    if (aMax > 0)
    {
      fPmDistSeq.push_back(aPmId);
      aDbCntVec[aRefIdx]--;
    }

    aIdx++;
  }
}

//------------------------------------------------------------------------------
/*
 * Build the sequence of distribution as a vector.
 */

//------------------------------------------------------------------------------
void BatchLoader::buildBatchDistSeqVector(uint32_t StartPm)
{
  fPmDistSeq.clear();
  BlIntVec aDbCntVec(fPMs.size());
  BlIntVec aPms;

  if ((fPMs.size() == 0) && (StartPm != 0))
    throw runtime_error("ERROR : PM list empty while Start != 0");

  // for (uint32_t i=0; i<fPMs.size(); i++)
  //	cout <<"fPM list  "<<i <<" = " << fPMs[i] << endl;
  // cout << "StartPm = "<< StartPm << endl;

  if (StartPm == 0)
    aPms = fPMs;
  else
  {
    aPms.push_back(StartPm);
    uint32_t aLast = fPMs.back();
    uint32_t aFirst = fPMs.front();

    // Add all the PMs with index more than "StartPm"
    for (uint32_t i = 0; i < fPMs.size(); i++)
    {
      if ((fPMs[i] > StartPm) && (fPMs[i] <= aLast))
        aPms.push_back(fPMs[i]);
    }

    // Add all the PMs with index less than "StartPm"
    for (uint32_t i = 0; i < fPMs.size(); i++)
    {
      if ((fPMs[i] < StartPm) && (fPMs[i] >= aFirst))
        aPms.push_back(fPMs[i]);
    }
  }

  std::map<int, OamCache::dbRoots>::iterator iter = fPmDbrootMap->begin();

  for (uint32_t i = 0; i < aPms.size(); i++)
  {
    iter = fPmDbrootMap->find(aPms[i]);

    if ((iter != fPmDbrootMap->end()) && ((iter->second).begin() != (iter->second).end()))
    {
      aDbCntVec[i] = (iter->second).size();
      // cout << "PM - "<<aPms[i] << " Size = " << aDbCntVec[i] << endl;
    }
    else
      aDbCntVec[i] = 0;
  }

  int aTotDbRoots = 0;

  for (uint32_t i = 0; i < aDbCntVec.size(); i++)
    aTotDbRoots += aDbCntVec[i];

  // cout << "DbCntVec Size = " << aDbCntVec.size() << " TotDbRoots = "<<aTotDbRoots << endl;

  int aIdx = 0;

  while (aIdx < aTotDbRoots)
  {
    uint32_t aMax = 0;
    uint32_t aPmId = 0;
    uint32_t aRefIdx = 0;

    for (uint32_t i = 0; i < aDbCntVec.size(); i++)
    {
      if (aDbCntVec[i] > aMax)
      {
        aMax = aDbCntVec[i];
        aPmId = aPms[i];
        aRefIdx = i;
      }
    }

    if (aMax > 0)
    {
      fPmDistSeq.push_back(aPmId);
      aDbCntVec[aRefIdx]--;
    }

    aIdx++;
  }

  // cout <<"PM Distribution vector size "<< fPmDistSeq.size() << endl;
  // for (uint32_t i=0; i<fPmDistSeq.size(); i++)
  //	cout <<"PM Distribution vector "<<i <<" = " << fPmDistSeq[i] << endl;
}

//------------------------------------------------------------------------------

uint32_t BatchLoader::selectNextPM()
{
  if (0 == fPmDistSeq.size())  // Dist sequence not ready. First time the function is called
  {
    uint32_t PMId = 0;
    // cout << "selectNextPM: size is 0. " << endl;
    selectFirstPM(PMId);
    return PMId;
  }

  if (fNextIdx >= fPmDistSeq.size())
    fNextIdx = 0;  // reset it

  return fPmDistSeq[fNextIdx++];
}

//------------------------------------------------------------------------------

void BatchLoader::reverseSequence()
{
  if (0 == fNextIdx)
    fNextIdx = fPmDistSeq.size() - 1;
  else
    fNextIdx--;
}

//------------------------------------------------------------------------------

void BatchLoader::prepareForSecondPM()
{
  // We loop thru by calling the selectNextPM()
  // When we get the aSecPm == aFirstPM, we will break so that when
  // we call the same function again when we come back get the next PM
  if ((fFirstPm != 0) && (fPMs.size() > 1))
  {
    unsigned int aSecPm = selectNextPM();

    while (fFirstPm != aSecPm)
      aSecPm = selectNextPM();
  }
}

}  // namespace batchloader