// MeshOptimizer - Copyright (C) 2013-2019 UCLouvain-ULiege
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use, copy,
// modify, merge, publish, distribute, and/or sell copies of the
// Software, and to permit persons to whom the Software is furnished
// to do so, provided that the above copyright notice(s) and this
// permission notice appear in all copies of the Software and that
// both the above copyright notice(s) and this permission notice
// appear in supporting documentation.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE
// COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR
// ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY
// DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
// WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
// ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
// OF THIS SOFTWARE.
//
// Contributors: Thomas Toulorge, Jonathan Lambrechts

#include <iostream>
#include <sstream>
#include <algorithm>
#include "GmshMessage.h"
#include "GmshConfig.h"
#include "ObjContrib.h"
#include "ObjectiveFunction.h"
#include "MeshOptCommon.h"
#include "MeshOpt.h"

#if defined(HAVE_ALGLIB)
#include <ap.h>
#include <alglibinternal.h>
#include <alglibmisc.h>
#include <linalg.h>
#include <optimization.h>
#endif

MeshOpt::MeshOpt(const std::map<MElement *, GEntity *> &element2entity,
                 const std::map<MElement *, GEntity *> &bndEl2Ent,
                 const std::set<MElement *> &els, std::set<MVertex *> &toFix,
                 const std::set<MElement *> &bndEls,
                 const MeshOptParameters &par)
  : patch(element2entity, bndEl2Ent, els, toFix, bndEls, par.fixBndNodes),
    _verbose(0), _nCurses(1), _iPass(0), _iter(0), _intervDisplay(0),
    _initObj(0)
{
  _allObjFunc.resize(par.pass.size());
  for(int iPass = 0; iPass < par.pass.size(); iPass++) {
    _allObjFunc[iPass].resize(par.pass[iPass].contrib.size());
    for(int iC = 0; iC < par.pass[iPass].contrib.size(); iC++)
      _allObjFunc[iPass][iC] = par.pass[iPass].contrib[iC]->copy();
  }
  _objFunc = &_allObjFunc[0];
  if(par.nCurses) {
    int minCol = 0;
    for(int i = 0; i < _objFunc->names().size(); i++) {
      if(i > 0) minCol += 5;
      minCol += 34;
      minCol += _objFunc->names()[i].size();
    }
    minCol = std::max(minCol, 96);
    int minRow = std::max(34, 34 + (int)_objFunc->names().size() - 5);
    int nbRow, nbCol;
    mvgetScreenSize(nbRow, nbCol);
    while(nbRow < minRow || nbCol < minCol) {
      for(int i = 0; i < nbRow; i++) { mvfillRow(i, ' '); }
      int firstRow = (nbRow - 5) / 2;
      mvprintCenter(
        firstRow,
        "Given the number of contributions to the objective function, ncurses");
      mvprintCenter(
        firstRow + 1,
        "enhanced interface requires a terminal window of minimal size");
      mvprintCenter(
        firstRow + 2,
        "%4ix%4i characters. Yours is %4ix%4i, try resizing the window", minRow,
        minCol, nbRow, nbCol);
      mvprintCenter(firstRow + 3, "then press SPACE.");
      mvpause();
      for(int i = 0; i < nbRow; i++) { mvfillRow(i, ' '); }
      mvbold(true);
      mvprintCenter(0, "OPTIMIZING MESH");
      mvfillRow(1, '-');
      mvfillRow(10, '-');
      mvfillRow(20, '-');
      mvfillRow(27, '-');
      mvbold(false);
      mvgetScreenSize(nbRow, nbCol);
    }
  }
}

MeshOpt::~MeshOpt()
{
  for(int iPass = 0; iPass < _allObjFunc.size(); iPass++)
    for(int iC = 0; iC < _allObjFunc[iPass].size(); iC++)
      delete _allObjFunc[iPass][iC];
  while(_optHistory.size() > 0) {
    delete[] _optHistory.back();
    _optHistory.pop_back();
  }
  while(_iterHistory.size() > 0) {
    delete[] _iterHistory.back();
    _iterHistory.pop_back();
  }
}

void MeshOpt::evalObjGrad(const std::vector<double> &x, double &obj,
                          std::vector<double> &gradObj)
{
  patch.updateMesh(&x[0]);
  _objFunc->compute(obj, gradObj);
  if(_objFunc->targetReached()) {
    if(_verbose > 2) Msg::Info("Reached target values, setting null gradient");
    obj = 0.;
    for(std::size_t i = 0; i < gradObj.size(); i++) gradObj[i] = 0.;
  }
}

ObjectiveFunction *MeshOpt::objFunction() { return _objFunc; }

void MeshOpt::printProgress(const std::vector<double> &x, double Obj)
{
  _iter++;

  if(_nCurses) {
    mvprintCenter(21,
                  "Iteration %3d --- OBJ %12.5E (relative decrease = %12.5E)",
                  _iter, Obj, Obj / _initObj);
    if(_iterHistory.size() < 5) { _iterHistory.push_back(new char[1000]); }
    else {
      _iterHistory.push_back(_iterHistory.front());
      _iterHistory.pop_front();
    }
    sprintf(_iterHistory.back(), _objFunc->minMaxStr().c_str());
    mvprintList(22, 5, _iterHistory, 1);
  }
  if((_verbose > 2) && (_iter % _intervDisplay == 0 || _nCurses))
    Msg::Info(("Iteration %3d " + _objFunc->minMaxStr() +
               " (obj %5E, rel decr %5E)").c_str(),
              _iter, Obj, Obj / _initObj);
}

void MeshOpt::calcScale(std::vector<double> &scale)
{
  scale.resize(patch.nPC());

  // Calculate scale
  for(int iFV = 0; iFV < patch.nFV(); iFV++) {
    std::vector<double> scaleFV(patch.nPCFV(iFV), 1.);
    patch.pcScale(iFV, scaleFV);
    for(int iPC = 0; iPC < patch.nPCFV(iFV); iPC++)
      scale[patch.indPCFV(iFV, iPC)] = scaleFV[iPC];
  }
}

void MeshOpt::updateResults() { _objFunc->updateResults(); }

#if defined(HAVE_ALGLIB)

static void evalObjGradFunc(const alglib::real_1d_array &x, double &Obj,
                            alglib::real_1d_array &gradObj, void *MOInst)
{
  std::vector<double> x_(x.getcontent(), x.getcontent() + x.length());
  std::vector<double> gradObj_(gradObj.length(), 0.);
  (static_cast<MeshOpt *>(MOInst))->evalObjGrad(x_, Obj, gradObj_);
  for(std::size_t i = 0; i < gradObj_.size(); i++) gradObj[i] = gradObj_[i];
}

static void printProgressFunc(const alglib::real_1d_array &x, double Obj,
                              void *MOInst)
{
  std::vector<double> x_(x.getcontent(), x.getcontent() + x.length());
  (static_cast<MeshOpt *>(MOInst))->printProgress(x_, Obj);
}

#endif

void MeshOpt::runOptim(std::vector<double> &x,
                       const std::vector<double> &initGradObj, int itMax,
                       int iBar)
{
  static const double EPSG = 0.;
  static const double EPSF = 0.;
  static const double EPSX = 0.;

  _iter = 0;

  std::vector<double> s;
  calcScale(s);

  int iterationscount = 0, nfev = 0, terminationtype = -1;

#if defined(HAVE_ALGLIB)
  alglib::real_1d_array scale;
  scale.setcontent(s.size(), &s[0]);
  alglib::real_1d_array vec;
  vec.setcontent(x.size(), &x[0]);
  alglib::mincgstate state;
  alglib::mincgreport rep;
  try {
    mincgcreate(vec, state);
    mincgsetscale(state, scale);
    mincgsetprecscale(state);
    mincgsetcond(state, EPSG, EPSF, EPSX, itMax);
    mincgsetxrep(state, true);
    alglib::mincgoptimize(state, evalObjGradFunc, printProgressFunc, this);
    mincgresults(state, vec, rep);
  } catch(alglib::ap_error &e) {
    Msg::Error("%s", e.msg.c_str());
  }
  x.assign(vec.getcontent(), vec.getcontent() + vec.length());
  iterationscount = rep.iterationscount;
  nfev = rep.nfev;
  terminationtype = rep.terminationtype;
#else
  // TODO: provide our own implementation!
  Msg::Error("Mesh optimizer requires ALGLIB");
#endif

  if(_nCurses) {
    if(_optHistory.size() < 8) { _optHistory.push_front(new char[1000]); }
    else {
      _optHistory.push_front(_optHistory.back());
      _optHistory.pop_back();
    }
    switch(int(terminationtype)) {
    case 1:
      sprintf(_optHistory.front(),
              "Optimization run %3d (%3d iterations, %3d function "
              "evaluations): rel function improvement <= EpsF",
              iBar, iterationscount, nfev);
      break;
    case 2:
      sprintf(_optHistory.front(),
              "Optimization run %3d (%3d iterations, %3d function "
              "evaluations): rel step <= EpsX                ",
              iBar, iterationscount, nfev);
      break;
    case 4:
      sprintf(_optHistory.front(),
              "Optimization run %3d (%3d iterations, %3d function "
              "evaluations): gradient norm <= EpsG           ",
              iBar, iterationscount, nfev);
      break;
    case 5:
      sprintf(_optHistory.front(),
              "Optimization run %3d (%3d iterations, %3d function "
              "evaluations): max number of steps taken       ",
              iBar, iterationscount, nfev);
      break;
    default:
      sprintf(
        _optHistory.front(),
        "Optimization run %3d (%3d iterations, %3d function evaluations): code "
        "%d                                              ",
        iBar, iterationscount, nfev, int(terminationtype));
      break;
    }
    if(_optHistory.size() < 8) { _optHistory.push_front(new char[1000]); }
    else {
      _optHistory.push_front(_optHistory.back());
      _optHistory.pop_back();
    }
    sprintf(_optHistory.front(), _iterHistory.back());
    mvprintList(19, -8, _optHistory, 2);
    while(_iterHistory.size() > 0) {
      delete[] _iterHistory.back();
      _iterHistory.pop_back();
    }
    mvprintList(22, 5, _iterHistory, 1);
  }
  if(_verbose > 2) {
    std::ostringstream sstream;
    sstream << "Optimization finalized after " << iterationscount
            << " iterations (" << nfev << " function evaluations)";
    switch(int(terminationtype)) {
    case 1: sstream <<
        ", because relative function improvement is no more than EpsF"; break;
    case 2: sstream << ", because relative step is no more than EpsX"; break;
    case 4: sstream << ", because gradient norm is no more than EpsG"; break;
    case 5: sstream << ", because the maximum number of steps was taken"; break;
    default: sstream << ", with code "<< int(terminationtype); break;
    }
    Msg::Info("%s", sstream.str().c_str());
  }
}

int MeshOpt::optimize(const MeshOptParameters &par)
{
  _intervDisplay = par.displayInterv;
  _verbose = par.verbose;
  _nCurses = par.nCurses;
  // Set initial guess & result
  int result = 1;
  std::vector<double> x(patch.nPC());
  patch.getUvw(&x[0]);
  if(_nCurses) {
    mvprintCenter(
      11, "%7i elements, %7i vertices, %7i free vertices, %7i variables",
      patch.nEl(), patch.nVert(), patch.nFV(), patch.nPC());
  }
  if(_verbose > 2)
    Msg::Info("Patch composed of %i elements, %i vertices, %i free vertices, "
              "%i variables",
              patch.nEl(), patch.nVert(), patch.nFV(), patch.nPC());

  // Loop on passes
  for(_iPass = 0; _iPass < par.pass.size(); _iPass++) {
    // Set objective function Output if required
    _objFunc = &_allObjFunc[_iPass];
    if(_verbose > 2) {
      std::string msgStr =
        " - Pass %d with contributions: " + _objFunc->contribNames();
      Msg::Info(msgStr.c_str(), _iPass);
    }

    // Initialize contributions
    _objFunc->initialize(&patch);
    _objFunc->updateParameters();

    // Calculate initial objective function value and gradient
    _initObj = 0.;
    std::vector<double> gradObj(patch.nPC(), 0.);
    evalObjGrad(x, _initObj, gradObj);

    // Loop for update of objective function parameters (barrier movement)
    bool targetReached = _objFunc->targetReached();
    for(int iBar = 0;
        (iBar < par.pass[_iPass].maxParamUpdates) && (!targetReached); iBar++) {
      if(_nCurses) {
        mvbold(true);
        mvprintCenter(20, " OPTIMIZATION RUN %3d ", iBar);
        mvbold(false);
        if(iBar == 0) {
          while(_optHistory.size() > 0) {
            delete[] _optHistory.back();
            _optHistory.pop_back();
          }
        }
        mvprintList(19, -8, _optHistory, 2);
      }
      if(_verbose > 2) {
        Msg::Info("Optimization run with barrier %d", iBar);
        Msg::Info(("Iteration %3d " + _objFunc->minMaxStr()).c_str(), 0);
      }
      _objFunc->updateParameters();
      runOptim(x, gradObj, par.pass[_iPass].maxOptIter, iBar);
      _objFunc->updateMinMax();
      targetReached = _objFunc->targetReached();
      if(_objFunc->stagnated()) {
        if(_verbose > 2)
          Msg::Info("Stagnation detected, stopping optimization");
        break;
      }
    }

    // Check results of pass and output if required
    if(!targetReached) result = 0;
    std::string failMeasures = _objFunc->failMeasures();
    if(!failMeasures.empty()) {
      result = -1;
      if(_verbose > 2)
        Msg::Error("Failed to reach critical value in pass %d "
                   "for measure(s): %s",
                   _iPass, failMeasures.c_str());
    }
    if(_verbose > 2) {
      if(targetReached)
        Msg::Info("Target reached for pass %d", _iPass);
      else {
        std::string failedTargets = _objFunc->targetsNotReached();
        Msg::Warning("Failed to reach target in pass %d for "
                     "contributions %s",
                     _iPass, failedTargets.c_str());
      }
    }
    if(result == -1) break;
  } // Pass loop

  return result;
}
