//===========================================================================//
// This file is part of the DIP Solver Framework.                            //
//                                                                           //
// DIP is distributed under the Eclipse Public License as part of the        //
// COIN-OR repository (http://www.coin-or.org).                              //
//                                                                           //
// Authors: Matthew Galati, SAS Institute Inc. (matthew.galati@sas.com)      //
//          Ted Ralphs, Lehigh University (ted@lehigh.edu)                   //
//          Jiadong Wang, Lehigh University (jiw408@lehigh.edu)              //
//                                                                           //
// Copyright (C) 2002-2015, Lehigh University, Matthew Galati, Ted Ralphs    //
// All Rights Reserved.                                                      //
//===========================================================================//

/**
 * \todo cleanup decomp status codes - scope them like Alps
 */

//===========================================================================//
#include "DecompAlgo.h"
#include "DecompApp.h"

//===========================================================================//
#include "AlpsKnowledgeBroker.h"
#include "AlpsDecompTreeNode.h"
#include "AlpsDecompNodeDesc.h"
#include "AlpsDecompSolution.h"
#include "AlpsDecompModel.h"

//===========================================================================//
#include "CoinUtility.hpp"

using namespace std;

//===========================================================================//
AlpsTreeNode*
AlpsDecompTreeNode::createNewTreeNode(AlpsNodeDesc*& desc) const
{
   //---
   //--- Create a new tree node, set node description.
   //---    NOTE: we are not using differencing, constructs node from scratch
   //---
   AlpsDecompModel*     model
   = dynamic_cast<AlpsDecompModel*>(desc->getModel());
   AlpsDecompParam&     param = model->getParam();
   UtilPrintFuncBegin(&cout, m_classTag,
                      "createNewTreeNode()", param.msgLevel, 3);
   AlpsDecompTreeNode* node = new AlpsDecompTreeNode();
   node->desc_ = desc;
   UtilPrintFuncEnd(&cout, m_classTag,
                    "createNewTreeNode()", param.msgLevel, 3);
   return node;
}

//===========================================================================//
bool AlpsDecompTreeNode::checkIncumbent(AlpsDecompModel*       model,
                                        const DecompSolution* decompSol)
{
   DecompAlgo*          decompAlgo = model->getDecompAlgo();
   //---
   //--- decompAlgo found an IP (and user) feasible point
   //---
   double currentUB   = getKnowledgeBroker()->getIncumbentValue();
   double candidateUB = decompSol->getQuality();
   UTIL_DEBUG(model->getParam().msgLevel, 3,
              cout
              << "DecompAlgo found IP incum = "
              << UtilDblToStr(candidateUB)
              << " currentUB " << UtilDblToStr(currentUB) << endl;
             );

   if (candidateUB < currentUB) {
      //---
      //--- create a new solution and add to alps knowledge
      //---
      AlpsDecompSolution* alpsDecompSol =
         new AlpsDecompSolution(decompSol->getSize(),
                                decompSol->getValues(),
                                decompSol->getQuality(),
                                decompAlgo->getDecompApp(),
                                getIndex(),
                                getDepth());
      getKnowledgeBroker()->addKnowledge(AlpsKnowledgeTypeSolution,
                                         alpsDecompSol,
                                         candidateUB);
      //---
      //--- print the new solution (if debugging)
      //---
      UTIL_DEBUG(model->getParam().msgLevel, 3,
                 const DecompApp            * app
                 = decompAlgo->getDecompApp();
                 const DecompConstraintSet  * modelCore
                 = decompAlgo->getModelCore().getModel();
                 app->printOriginalSolution(decompSol->getSize(),
                                            modelCore->getColNames(),
                                            decompSol->getValues()););
      return true;
   }

   return false;
}

//===========================================================================//
int AlpsDecompTreeNode::process(bool isRoot,
                                bool rampUp)
{
   //---
   //--- get pointer / reference to model, node description, decomp algo(s)
   //---
   AlpsDecompNodeDesc* desc
   = dynamic_cast<AlpsDecompNodeDesc*>(desc_);
   AlpsDecompModel*     model
   = dynamic_cast<AlpsDecompModel*>(desc->getModel());
   AlpsDecompParam&     param      = model->getParam();
   DecompAlgo*          decompAlgo = model->getDecompAlgo();
   CoinAssertDebug(desc && model);
   UtilPrintFuncBegin(&cout, m_classTag,
                      "process()", param.msgLevel, 3);
   UTIL_DEBUG(param.msgLevel, 3,
              cout
              << "Start process of node: " << getIndex()
              << " (parent = " << getParentIndex() << ")" << endl;
             );
   int            status       = AlpsReturnStatusOk;
   bool           doFathom     = false;
   DecompStatus   decompStatus = STAT_FEASIBLE;
   double         relTolerance = 0.0001; //0.01% means optimal (make param)
   double         gap;
   //---
   //--- check if this can be fathomed based on parent by objective cutoff
   //---
   double currentUB       = getKnowledgeBroker()->getIncumbentValue();
   double parentObjValue  = getQuality();
   double primalTolerance = 1.0e-6;
   double globalLB        = -DecompInf;
   double globalUB        =  DecompInf;
   double thisQuality;
   AlpsTreeNode*         bestNode  = NULL;
   const double*         lbs       = desc->lowerBounds_;
   const double*         ubs       = desc->upperBounds_;
   const DecompApp*      app       = decompAlgo->getDecompApp();
   DecompConstraintSet* modelCore = decompAlgo->getModelCore().getModel();
   const int             n_cols    = modelCore->getNumCols();
   //TODO: cutoffIncrement (currentUB-cutoffIncrement)

   /** \todo get primalTolerance from parameter */
   if ((parentObjValue - primalTolerance) > currentUB) {
      doFathom = true;
      UTIL_DEBUG(param.msgLevel, 3,
                 cout << "Fathom since parentObjValue="
                 << setw(10) << UtilDblToStr(parentObjValue)
                 << " currentUB = " << setw(10) << UtilDblToStr(currentUB) << endl;
                );
      goto TERM_PROCESS;
   }

   //---
   //--- the destructor initializes quality_ = infinity
   //---   we really want -infinity
   //---
   if (isRoot) {
      quality_ = -ALPS_OBJ_MAX;
   }

   //---
   //--- reset user-currentUB (if none given, this will have no effect)
   //---
   decompAlgo->setObjBoundIP(decompAlgo->getCutoffUB());

   if (!isRoot) {
      //---
      //--- set the master column bounds (for this node in tree)
      //---
      //---
      //--- for debugging, print column bounds that differ from original
      //---
      UTIL_MSG(param.msgLevel, 3,
               int              c;
               double           diffLB;
               double           diffUB;
               vector<double>& colLBCore = modelCore->colLB;
               vector<double>& colUBCore = modelCore->colUB;

      for (c = 0; c < n_cols; c++) {
      diffLB = lbs[c] - colLBCore[c];
         diffUB = ubs[c] - colUBCore[c];

         if (!UtilIsZero(diffLB) || !UtilIsZero(diffUB)) {
            cout << "bound-diffs c: " << c << " -> ";
            app->printOriginalColumn(c, &cout);
            cout << "\t(lb,ub): (" << colLBCore[c] << ","
            << colUBCore[c] << ")\t->\t(" << lbs[c]
            << "," << ubs[c] << ")" << endl;
         }
      }
              );
      decompAlgo->setMasterBounds(lbs, ubs);
      decompAlgo->setSubProbBounds(lbs, ubs);
   } else {
      //---
      //--- check to see if we got lucky in generating init vars
      //---
      if (decompAlgo->getXhatIPBest()) {
         checkIncumbent(model, decompAlgo->getXhatIPBest());
      }

      //---
      //--- This is a first attempt at a redesign of branching rows.
      //---  We still have all of them explicitly defined, but we
      //---  relax them and only explicitly enforce things as we branch.
      //---
      //--- A more advanced attempt would treat branching rows as cuts
      //---  and add them dynamically.
      //---
      //--- In root node, set all branching rows to "free" by relaxing
      //---   lb and ub.
      //---
      //--- NOTE: this should also be done for all nodes except for the
      //---   rows that represent bounds that we have branched on.
      //---
      if (decompAlgo->getAlgo() == PRICE_AND_CUT) {
         int      c;
         double* lbsInf = new double[n_cols];
         double* ubsInf = new double[n_cols];

         for (c = 0; c < n_cols; c++) {
            lbsInf[c] = -DecompInf;
            ubsInf[c] =  DecompInf;
            //printf("root c:%d lb=%g ub=%g\n",
            //   c, lbs[c], ubs[c]);
         }

         decompAlgo->setMasterBounds(lbsInf, ubsInf);
         UTIL_DELARR(lbsInf);
         UTIL_DELARR(ubsInf);
         //actually, don't need to do this - these should already be set
         decompAlgo->setSubProbBounds(lbs, ubs);
      }
   }

   //---
   //--- update the currentUB value for decomp algo
   //---
   currentUB = getKnowledgeBroker()->getIncumbentValue();
   decompAlgo->setObjBoundIP(currentUB);//??
   gap      = DecompInf;
   globalUB = getKnowledgeBroker()->getIncumbentValue();

   if (!isRoot) {
      bestNode = getKnowledgeBroker()->getBestNode();
      globalLB = bestNode->getQuality();
      //---
      //--- if the overall gap is tight enough, fathom whatever is left
      //---
      //TODO: cutoffIncrement (currentUB-cutoffIncrement)
      gap = UtilCalculateGap(globalLB, globalUB);

      if (gap <= relTolerance) {
         doFathom = true;
         UTIL_MSG(param.msgLevel, 3,
                  cout << "Fathom Node " << getIndex() << " since globalLB= "
                  << setw(10) << UtilDblToStr(globalLB)
                  << " globalUB = "  << setw(10) << UtilDblToStr(globalUB)
                  << " gap = "     << setw(10) << UtilDblToStr(gap) << endl;
                 );
         goto TERM_PROCESS;
      }
   }

   //---
   //--- solve the bounding problem (DecompAlgo)
   //---
   decompStatus = decompAlgo->processNode(this, globalLB, globalUB);

   //---
   //--- during processNode, did we find any IP feasible points?
   //---
   if (decompAlgo->getXhatIPBest()) {
      if (checkIncumbent(model, decompAlgo->getXhatIPBest())) {
         decompStatus = STAT_IP_FEASIBLE;
      }

      //---
      //--- update the local currentUB value and the decomp global UB
      //---
      currentUB = getKnowledgeBroker()->getIncumbentValue();
      decompAlgo->setObjBoundIP(currentUB);
   }

   switch (decompStatus) {
   case STAT_FEASIBLE:
   case STAT_IP_FEASIBLE:
      //---
      //--- the relaxation is feasible
      //---   if the new bound is > current currentUB, fathom
      //---   else                                , branch
      //---
      thisQuality = decompAlgo->getObjBestBoundLB();           //LB (min)
      currentUB      = getKnowledgeBroker()->getIncumbentValue(); //UB (min)

      if (thisQuality > quality_) {
         quality_ = thisQuality;
      }

      //watch tolerance here... if quality is close enough, fathom it
      gap = UtilCalculateGap(thisQuality, currentUB);

      //if(gap <= relTolerance){
      if (quality_ >= currentUB) {
         doFathom = true;
         UTIL_DEBUG(param.msgLevel, 3,
                    cout << "Fathom since thisQuality= "
                    << setw(10) << UtilDblToStr(thisQuality)
                    << " quality_= " << setw(10) << UtilDblToStr(quality_)
                    << " currentUB = "  << setw(10) << UtilDblToStr(currentUB)
                    << " gap = "     << setw(10) << UtilDblToStr(gap) << endl;
                   );
      }

      UTIL_MSG(param.msgLevel, 3,
               cout << "Node " << getIndex()
               << " quality " << UtilDblToStr(quality_)
               << " currentUB "  << UtilDblToStr(currentUB)
               << " doFathom " << doFathom << endl;
              );
      break;
   case STAT_INFEASIBLE:
      //---
      //--- the relaxation is infeasible, fathom
      //---
      thisQuality = -ALPS_OBJ_MAX;
      doFathom    = true;
      UTIL_MSG(param.msgLevel, 3,
               cout << "Fathom since node infeasible\n";
              );
      break;
   default:
      assert(0);
   }

   //TODO: control by decomp log level?
   UTIL_MSG(param.msgLevel, 3,
            cout << "Node " << getIndex()
            << " bestQuality "  << UtilDblToStr(quality_)
            << " bestFeasible " << UtilDblToStr(currentUB) << endl;
           );
TERM_PROCESS:
   //STOP: if do fathom when node limit hit, then it gives wrong LB
   //  what is the proper status setting if node limit is hit to stop
   //  but not fathom so as to lose the proper bound
   //if(param.nodeLimit == 0)
   //   status = AlpsExitStatusNodeLimit;
   //---
   //--- for nodeLimit == 0, we do not want it to look for
   //---   branching candidates since in some cases we stop due to
   //---   gap without a branching candidate and do not want to have to
   //---   return (since we are not evaluating any more nodes anyway)
   //--- so, we fake it by acting like a branching candidate was found
   //---
   decompAlgo->postProcessNode(decompStatus);

   if (param.nodeLimit == 0) {
      setStatus(AlpsNodeStatusPregnant);
   } else if (doFathom) { // || param.nodeLimit == 0){
      setStatus(AlpsNodeStatusFathomed);
   } else {
      status = chooseBranchingObject(model);
      if (getStatus() == AlpsNodeStatusPregnant){
	 decompAlgo->postProcessBranch(decompStatus);
      }
   }

   UtilPrintFuncEnd(&cout, m_classTag,
                    "process()", param.msgLevel, 3);
   return status;
}

//===========================================================================//
int AlpsDecompTreeNode::chooseBranchingObject(AlpsModel* model)
{
   AlpsDecompNodeDesc* desc =
      dynamic_cast<AlpsDecompNodeDesc*>(desc_);
   AlpsDecompModel* m     = dynamic_cast<AlpsDecompModel*>(desc->getModel());
   AlpsDecompParam& param = m->getParam();
   UtilPrintFuncBegin(&cout, m_classTag, "chooseBranchingObject()",
                      param.msgLevel, 3);
   bool gotBranch = m->getDecompAlgo()->chooseBranchSet(downBranchLB_,
                    downBranchUB_,
                    upBranchLB_,
                    upBranchUB_);

   if (!gotBranch) {
      setStatus(AlpsNodeStatusEvaluated);
      //---
      //--- but if we can't branch on this and it DID finish pricing out
      //---   that means DW_LB=DW_UB for that node, then we are done
      //---   processing it and we should fathom(?)
      //--- all we have to check is that LB=UB, since LB is updated
      //--- despite the tailoff - so their should be a gap...
      //--- the UB for this node, not the global UB...
      //---
      //printf("BestLB at this Node = %g\n", decompAlgo->getObjBestBoundLB());
      //printf("BestLB at this Node = %g\n", decompAlgo->getObjBestBoundUB();)
   } else {
      //---
      //--- we can go ahead and branch on this variable
      //---   meaning we will produce children (hence, the name pregnant)
      //---
      setStatus(AlpsNodeStatusPregnant);
   }

   UtilPrintFuncEnd(&cout, m_classTag, "chooseBranchingObject()",
                    param.msgLevel, 3);
   return AlpsReturnStatusOk;
}

//===========================================================================//
std::vector< CoinTriple<AlpsNodeDesc*, AlpsNodeStatus, double> >
AlpsDecompTreeNode::branch()
{
   AlpsDecompNodeDesc* desc
   = dynamic_cast<AlpsDecompNodeDesc*>(desc_);
   AlpsDecompModel*     m
   = dynamic_cast<AlpsDecompModel*>(desc->getModel());
   AlpsDecompParam&     param       = m->getParam();
   AlpsDecompNodeDesc* child       = 0;
   DecompAlgo*          decompAlgo  = m->getDecompAlgo();
   DecompParam&         decompParam = decompAlgo->getMutableParam();
   UtilPrintFuncBegin(&cout, m_classTag, "branch()", param.msgLevel, 3);
   //---
   //--- the return of the branch method expects a vector of triples
   //--- that contain the following:
   //---    (1) AlpsNodeDesc* - a ptr to the node description
   //---    (2) AlpsNodeStatus - the inital status of the node (candidate)
   //---    (3) double - the objective best lower bound
   //---
   std::vector< CoinTriple<AlpsNodeDesc*, AlpsNodeStatus, double> > newNodes;
   //---
   //--- get the current node's lb/ub in original space
   //---
   double*   oldLbs  = desc->lowerBounds_;
   double*   oldUbs  = desc->upperBounds_;
   const int numCols = desc->numberCols_;
   CoinAssert(oldLbs && oldUbs && numCols);

   //---
   //--- check to make sure the branching variables have been determined
   //---
   if ((downBranchLB_.size() + downBranchUB_.size() == 0) ||
         (upBranchLB_.size()   + upBranchUB_.size()   == 0)) {
      std::cout << "AlpsDecompError: "
                << "downBranch_.size() = "
                << downBranchLB_.size() + downBranchUB_.size()
                << "; upBranch_.size() = "
                << upBranchLB_.size() + upBranchUB_.size()
                << "; index_ = " << index_ << std::endl;
      throw CoinError("empty branch variable set(s)",
                      "branch", "AlpsDecompTreeNode");
   }

   //---
   //--- create space for the new bounds for the children
   //---
   double* newLbs = new double[numCols];
   double* newUbs = new double[numCols];
   std::copy(oldLbs, oldLbs + numCols, newLbs);
   std::copy(oldUbs, oldUbs + numCols, newUbs);
   //---
   //--- the objective estimate of the new nodes are init'd to the
   //---  current node's objective (the new node's parent's objective)
   //---
   double objVal(getQuality());

   //---
   //--- Branch down
   //---
   for (unsigned i = 0; i < downBranchLB_.size(); i++) {
      if ((downBranchLB_[i].first < 0) ||
            (downBranchLB_[i].first >= numCols)) {
         std::cout << "AlpsDecompError: downBranchLB_[" << i << "] variable = "
                   << downBranchLB_[i].first << "; numCols = "
                   << numCols << "; index_ = " << index_ << std::endl;
         throw CoinError("branch index is out of range",
                         "branch", "AlpsDecompTreeNode");
      }

      newLbs[downBranchLB_[i].first] = downBranchLB_[i].second;
   }

   for (unsigned i = 0; i < downBranchUB_.size(); i++) {
      if ((downBranchUB_[i].first < 0) ||
            (downBranchUB_[i].first >= numCols)) {
         std::cout << "AlpsDecompError: downBranchUB_[" << i << "] variable = "
                   << downBranchUB_[i].first << "; numCols = "
                   << numCols << "; index_ = " << index_ << std::endl;
         throw CoinError("branch index is out of range",
                         "branch", "AlpsDecompTreeNode");
      }

      newUbs[downBranchUB_[i].first] = downBranchUB_[i].second;
   }

   assert(downBranchLB_.size() + downBranchUB_.size() > 0);
   child = new AlpsDecompNodeDesc(m, newLbs, newUbs);
   child->setBranchedDir(-1);//enum?

   if (decompParam.BranchStrongIter) {
      double globalUB             = getKnowledgeBroker()->getIncumbentValue();
      int    solveMasterAsMip      = decompParam.SolveMasterAsMip;
      int    limitTotalCutIters   = decompParam.TotalCutItersLimit;
      int    limitTotalPriceIters = decompParam.TotalPriceItersLimit;
      //---
      //--- calculate an estimate on the lower bound after branching
      //---
      //decompParam.TotalCutItersLimit   = decompParam.BranchStrongIter;
      decompParam.TotalCutItersLimit   = 0;
      decompParam.TotalPriceItersLimit = decompParam.BranchStrongIter;
      decompParam.SolveMasterAsMip      = 0;
      decompAlgo->setStrongBranchIter(true);
      decompAlgo->setMasterBounds(newLbs, newUbs);
      decompAlgo->setSubProbBounds(newLbs, newUbs);
      decompAlgo->processNode(this, objVal, globalUB);
      decompAlgo->setStrongBranchIter(false);
      decompParam.TotalCutItersLimit   = limitTotalCutIters;
      decompParam.TotalPriceItersLimit = limitTotalPriceIters;
      decompParam.SolveMasterAsMip      = solveMasterAsMip;
      //TOOD: what if it stops in Phase1
      //how will this work in CPM?
   }

   newNodes.push_back(CoinMakeTriple(static_cast<AlpsNodeDesc*>(child),
                                     AlpsNodeStatusCandidate,
                                     objVal));
   //---
   //--- Branch up
   //---
   //TODO: this can be done more cheaply than a full copy
   std::copy(oldLbs, oldLbs + numCols, newLbs);
   std::copy(oldUbs, oldUbs + numCols, newUbs);

   for (unsigned i = 0; i < upBranchLB_.size(); i++) {
      if ((upBranchLB_[i].first < 0) ||
            (upBranchLB_[i].first >= numCols)) {
         std::cout << "AlpsDecompError: upBranchLB_[" << i << "] variable = "
                   << upBranchLB_[i].first << "; numCols = "
                   << numCols << "; index_ = " << index_ << std::endl;
         throw CoinError("branch index is out of range",
                         "branch", "AlpsDecompTreeNode");
      }

      newLbs[upBranchLB_[i].first] = upBranchLB_[i].second;
   }

   for (unsigned i = 0; i < upBranchUB_.size(); i++) {
      if ((upBranchUB_[i].first < 0) ||
            (upBranchUB_[i].first >= numCols)) {
         std::cout << "AlpsDecompError: upBranchUB_[" << i << "] variable = "
                   << upBranchUB_[i].first << "; numCols = "
                   << numCols << "; index_ = " << index_ << std::endl;
         throw CoinError("branch index is out of range",
                         "branch", "AlpsDecompTreeNode");
      }

      newUbs[upBranchUB_[i].first] = upBranchUB_[i].second;
   }

   assert(upBranchLB_.size() + upBranchUB_.size() > 0);
   child = new AlpsDecompNodeDesc(m, newLbs, newUbs);
   child->setBranchedDir(1);//enum?

   if (decompParam.BranchStrongIter) {
      double globalUB             = getKnowledgeBroker()->getIncumbentValue();
      int    solveMasterAsMip      = decompParam.SolveMasterAsMip;
      int    limitTotalCutIters   = decompParam.TotalCutItersLimit;
      int    limitTotalPriceIters = decompParam.TotalPriceItersLimit;
      //---
      //--- calculate an estimate on the lower bound after branching
      //---
      //decompParam.TotalCutItersLimit   = decompParam.BranchStrongIter;
      decompParam.TotalCutItersLimit   = 0;
      decompParam.TotalPriceItersLimit = decompParam.BranchStrongIter;
      decompParam.SolveMasterAsMip      = 0;
      decompAlgo->setStrongBranchIter(true);
      decompAlgo->setMasterBounds(newLbs, newUbs);
      decompAlgo->setSubProbBounds(newLbs, newUbs);
      decompAlgo->processNode(this, objVal, globalUB);
      decompAlgo->setStrongBranchIter(false);
      decompParam.TotalCutItersLimit   = limitTotalCutIters;
      decompParam.TotalPriceItersLimit = limitTotalPriceIters;
      decompParam.SolveMasterAsMip      = solveMasterAsMip;
   }

   newNodes.push_back(CoinMakeTriple(static_cast<AlpsNodeDesc*>(child),
                                     AlpsNodeStatusCandidate,
                                     objVal));

   //---
   //--- clean-up
   //---
   if (newLbs != 0) {
      delete [] newLbs;
      newLbs = 0;
   }

   if (newUbs != 0) {
      delete [] newUbs;
      newUbs = 0;
   }

   //---
   //--- change this node's status to branched
   //---
   setStatus(AlpsNodeStatusBranched);
   UtilPrintFuncEnd(&cout, m_classTag, "branch()", param.msgLevel, 3);
   return newNodes;
}

