// @HEADER
// *****************************************************************************
//               Rapid Optimization Library (ROL) Package
//
// Copyright 2014 NTESS and the ROL contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#include "ROL_ParameterList.hpp"

#include "ROL_Stream.hpp"
#include "ROL_GlobalMPISession.hpp"

#include "ROL_StdVector.hpp"
#include "ROL_StdBoundConstraint.hpp"
#include "ROL_Types.hpp"

#include "ROL_OptimizationProblem.hpp"
#include "ROL_Solver.hpp"
#include "ROL_Objective.hpp"
#include "ROL_BatchManager.hpp"
#include "ROL_MonteCarloGenerator.hpp"

typedef double RealT;

template<class Real>
class ParametrizedObjectiveEx8 : public ROL::Objective<Real> {
public:
  Real value( const ROL::Vector<Real> &x, Real &tol ) {
    ROL::Ptr<const std::vector<Real>> ex = 
      dynamic_cast<const ROL::StdVector<Real>&>(x).getVector();
    Real quad = 0.0, lin = 0.0;
    std::vector<Real> p = this->getParameter();
    unsigned size = ex->size();
    for ( unsigned i = 0; i < size; i++ ) {
      quad += (*ex)[i]*(*ex)[i];
      lin  += (*ex)[i]*p[i+1];
    }
    return std::exp(p[0])*quad + lin + p[size+1];
  }

  void gradient( ROL::Vector<Real> &g, const ROL::Vector<Real> &x, Real &tol ) {
    ROL::Ptr<const std::vector<Real>> ex = 
      dynamic_cast<const ROL::StdVector<Real>&>(x).getVector();
    ROL::Ptr<std::vector<Real>> eg =
      dynamic_cast<ROL::StdVector<Real>&>(g).getVector();
    std::vector<Real> p = this->getParameter();
    unsigned size = ex->size();
    for ( unsigned i = 0; i < size; i++ ) {
      (*eg)[i] = 2.0*std::exp(p[0])*(*ex)[i] + p[i+1];
    }
  }

  void hessVec( ROL::Vector<Real> &hv, const ROL::Vector<Real> &v, const ROL::Vector<Real> &x, Real &tol ) {
    ROL::Ptr<const std::vector<Real>> ex = 
      dynamic_cast<const ROL::StdVector<Real>&>(x).getVector();
    ROL::Ptr<const std::vector<Real>> ev = 
      dynamic_cast<const ROL::StdVector<Real>&>(v).getVector();
    ROL::Ptr<std::vector<Real>> ehv =
      dynamic_cast<ROL::StdVector<Real>&>(hv).getVector();
    std::vector<Real> p = this->getParameter();
    unsigned size = ex->size();
    for ( unsigned i = 0; i < size; i++ ) {
      (*ehv)[i] = 2.0*std::exp(p[0])*(*ev)[i];
    }
  }
};

RealT setUpAndSolve(ROL::ParameterList                    & list,
                    ROL::Ptr<ROL::Objective<RealT>>       & pObj,
                    ROL::Ptr<ROL::SampleGenerator<RealT>> & sampler,
                    ROL::Ptr<ROL::Vector<RealT>>          & x,
                    ROL::Ptr<ROL::BoundConstraint<RealT>> & bnd,
                    std::ostream                          & outStream) {
  ROL::OptimizationProblem<RealT> opt(pObj,x,bnd);
  opt.setStochasticObjective(list,sampler);
  ROL::Ptr<ROL::Problem<RealT>>
    newprob = ROL::makePtr<ROL::Problem<RealT>>(opt.getObjective(),opt.getSolutionVector());
  if (opt.getBoundConstraint()->isActivated())
    newprob->addBoundConstraint(opt.getBoundConstraint());
  outStream << "\nCheck Derivatives of Stochastic Objective Function\n";
  newprob->check(true,outStream);
  // Run ROL algorithm
  list.sublist("Step").set("Type","Trust Region");
  ROL::Solver<RealT> solver(newprob,list);
  solver.solve(outStream);
  ROL::Ptr<ROL::Objective<RealT>> robj = opt.getObjective();
  RealT tol(1.e-8);
  return robj->value(*(opt.getSolutionVector()),tol);
}

void setRandomVector(std::vector<RealT> &x) {
  unsigned dim = x.size();
  for ( unsigned i = 0; i < dim; i++ ) {
    x[i] = (RealT)rand()/(RealT)RAND_MAX;
  }
}

void printSolution(const std::vector<RealT> &x,
                   std::ostream & outStream) {
  unsigned dim = x.size();
  outStream << "x = (";
  for ( unsigned i = 0; i < dim-1; i++ ) {
    outStream << x[i] << ", ";
  }
  outStream << x[dim-1] << ")\n";
}

int main(int argc, char* argv[]) {

  ROL::GlobalMPISession mpiSession(&argc, &argv);

  // This little trick lets us print to std::cout only if a (dummy) command-line argument is provided.
  int iprint     = argc - 1;
  bool print     = iprint > 0;
  ROL::Ptr<std::ostream> outStream;
  ROL::nullstream bhs; // outputs nothing
  if (iprint > 0)
    outStream = ROL::makePtrFromRef(std::cout);
  else
    outStream = ROL::makePtrFromRef(bhs);

  int errorFlag  = 0;

  try {
    /**********************************************************************************************/
    /************************* CONSTRUCT ROL ALGORITHM ********************************************/
    /**********************************************************************************************/
    // Get ROL parameterlist
    std::string filename = "input_09.xml";
    
    auto parlist = ROL::getParametersFromXmlFile( filename );
    ROL::ParameterList list = *parlist;
    list.sublist("General").set("Output Level",print ? 1 : 0);
    /**********************************************************************************************/
    /************************* CONSTRUCT SOL COMPONENTS *******************************************/
    /**********************************************************************************************/
    // Build vectors
    unsigned dim = 4;
    ROL::Ptr<std::vector<RealT>> x_ptr = ROL::makePtr<std::vector<RealT>>(dim,0.0);
    ROL::Ptr<ROL::Vector<RealT>> x = ROL::makePtr<ROL::StdVector<RealT>>(x_ptr);
    ROL::Ptr<std::vector<RealT>> d_ptr = ROL::makePtr<std::vector<RealT>>(dim,0.0);
    ROL::Ptr<ROL::Vector<RealT>> d = ROL::makePtr<ROL::StdVector<RealT>>(d_ptr);
    setRandomVector(*d_ptr);
    // Build samplers
    int nSamp = 1000;
    unsigned sdim = dim + 2;
    std::vector<RealT> tmp(2,0.); tmp[0] = -1.; tmp[1] = 1.;
    std::vector<std::vector<RealT>> bounds(sdim,tmp);
    ROL::Ptr<ROL::BatchManager<RealT>> bman =
      ROL::makePtr<ROL::BatchManager<RealT>>();
    ROL::Ptr<ROL::SampleGenerator<RealT>> sampler =
      ROL::makePtr<ROL::MonteCarloGenerator<RealT>>(nSamp,bounds,bman,false,false,100);
    // Build risk-averse objective function
    ROL::Ptr<ROL::Objective<RealT>> pObj =
      ROL::makePtr<ParametrizedObjectiveEx8<RealT>>();
    // Build bound constraints
    std::vector<RealT> l(dim,0.0);
    std::vector<RealT> u(dim,1.0);
    ROL::Ptr<ROL::BoundConstraint<RealT>> bnd = 
      ROL::makePtr<ROL::StdBoundConstraint<RealT>>(l,u);
    bnd->deactivate();
    // Test parametrized objective functions
    *outStream << "Check Derivatives of Parametrized Objective Function\n";
    pObj->setParameter(sampler->getMyPoint(0));
    pObj->checkGradient(*x,*d,true,*outStream);
    pObj->checkHessVec(*x,*d,true,*outStream);
    /**********************************************************************************************/
    /************************* SUPER QUANTILE QUADRANGLE ******************************************/
    /**********************************************************************************************/
    RealT one(1), err(0);
    int nQuadLo = 0, nQuadUp = 21, order = 0;
    std::vector<RealT> norm(nQuadUp-nQuadLo), obj(nQuadUp-nQuadLo);
    *outStream << "\nSPECTRAL RISK MEASURE\n";
    list.sublist("SOL").set("Type","Risk Averse");
    list.sublist("SOL").sublist("Risk Measure").set("Name","Spectral Risk");
    std::vector<ROL::Ptr<std::vector<RealT>>> hist(nQuadUp-nQuadLo,ROL::nullPtr);
    std::vector<ROL::Ptr<ROL::StdVector<RealT>>> hvec(nQuadUp-nQuadLo,ROL::nullPtr);
    for (int i = nQuadLo; i < nQuadUp; ++i) {
      order = i+1;
      list.sublist("SOL").sublist("Risk Measure").sublist("Spectral Risk").set("Number of Quadrature Points",order);
      setRandomVector(*x_ptr);
      obj[i-nQuadLo] = setUpAndSolve(list,pObj,sampler,x,bnd,*outStream);
      norm[i]  = x->norm();
      hist[i-nQuadLo] = ROL::makePtr<std::vector<RealT>>(dim);
      hvec[i-nQuadLo] = ROL::makePtr<ROL::StdVector<RealT>>(hist[i-nQuadLo]);
      hvec[i-nQuadLo]->set(*x);
      printSolution(*x_ptr,*outStream);
    }
    *outStream << std::right
               << std::setw(20) << "Num quad"
               << std::setw(20) << "norm x"
               << std::setw(20) << "x error"
               << std::setw(20) << "obj val"
               << std::setw(20) << "obj error"
               << std::endl;
    for (int i = nQuadLo; i < nQuadUp-1; ++i) {
      hvec[i-nQuadLo]->axpy(-one,*x);
      err = std::abs(obj[i]-obj[nQuadUp-nQuadLo-1]);
      *outStream << std::fixed << std::setprecision(0) << std::right
                 << std::setw(20) << static_cast<RealT>(i+1)
                 << std::scientific << std::setprecision(11) << std::right
                 << std::setw(20) << norm[i]
                 << std::setw(20) << hvec[i-nQuadLo]->norm()
                 << std::setw(20) << obj[i]
                 << std::setw(20) << err
                 << std::endl;
    }
    errorFlag += ((err > static_cast<RealT>(1.e-2)) ? 1 : 0);
  }
  catch (std::logic_error& err) {
    *outStream << err.what() << "\n";
    errorFlag = -1000;
  }; // end try

  if (errorFlag != 0)
    std::cout << "End Result: TEST FAILED\n";
  else
    std::cout << "End Result: TEST PASSED\n";

  return 0;
}
