#include <config.h>

#include <dune/common/parametertree.hh>
#include <dune/common/parametertreeparser.hh>

#include <dune/grid/uggrid.hh>
#include <dune/grid/io/file/gmshreader.hh>
#include <dune/grid/utility/structuredgridfactory.hh>

#include <dune/functions/functionspacebases/pqknodalbasis.hh>

#include <dune/fufem/boundarypatch.hh>
#include <dune/fufem/functiontools/basisinterpolator.hh>
#include <dune/fufem/functiontools/boundarydofs.hh>
#include <dune/fufem/functionspacebases/dunefunctionsbasis.hh>
#include <dune/fufem/discretizationerror.hh>
#include <dune/fufem/dunepython.hh>

#include <dune/gfe/rotation.hh>
#include <dune/gfe/unitvector.hh>
#include <dune/gfe/realtuple.hh>
#include <dune/gfe/embeddedglobalgfefunction.hh>
#include <dune/gfe/cosseratvtkwriter.hh>

// grid dimension
const int dim = 2;
const int dimworld = 2;

// Image space of the geodesic fe functions
const int targetDim = 3;
// typedef Rotation<double,targetDim> TargetSpace;
// typedef UnitVector<double,targetDim> TargetSpace;
// typedef RealTuple<double,targetDim> TargetSpace;
using TargetSpace = RigidBodyMotion<double,targetDim>;

// Tangent vector of the image space
const int blocksize = TargetSpace::TangentVector::dimension;

using namespace Dune;

template <class GridView, int order>
void measureEOC(const GridView gridView,
                const GridView referenceGridView,
                const ParameterTree& parameterSet)
{
  typedef std::vector<TargetSpace> SolutionType;

  //////////////////////////////////////////////////////////////////////////////////
  //  Construct the scalar function space bases corresponding to the GFE space
  //////////////////////////////////////////////////////////////////////////////////

  typedef Dune::Functions::PQkNodalBasis<GridView, order> FEBasis;
  FEBasis feBasis(gridView);

  //////////////////////////////////////////////////////////////////////////////////
  //  Read the data whose error is to be measured
  //////////////////////////////////////////////////////////////////////////////////

  // Input data
  typedef BlockVector<TargetSpace::CoordinateType> EmbeddedVectorType;

  EmbeddedVectorType embeddedX(feBasis.size());
  std::ifstream inFile(parameterSet.get<std::string>("simulationData"), std::ios_base::binary);
  if (not inFile)
    DUNE_THROW(IOError, "File " << parameterSet.get<std::string>("simulationData") << " could not be opened.");
  GenericVector::readBinary(inFile, embeddedX);
  inFile.close();

  SolutionType x(embeddedX.size());
  for (size_t i=0; i<x.size(); i++)
    x[i] = TargetSpace(embeddedX[i]);

  /////////////////////////////////////////////////////////////////
  //   Measure the discretization error
  /////////////////////////////////////////////////////////////////

  if (parameterSet.get<std::string>("discretizationErrorMode")=="analytical")
  {
    using FufemFEBasis = DuneFunctionsBasis<FEBasis>;
    FufemFEBasis fufemFEBasis(feBasis);

    // Read reference solution and its derivative into a PythonFunction
    typedef VirtualDifferentiableFunction<FieldVector<double, dim>, TargetSpace::CoordinateType> FBase;

    Python::Module module = Python::import(parameterSet.get<std::string>("referenceSolution"));
    auto referenceSolution = module.get("fdf").toC<std::shared_ptr<FBase>>();

    // The numerical solution, as a grid function
    GFE::EmbeddedGlobalGFEFunction<FufemFEBasis, TargetSpace> numericalSolution(fufemFEBasis, x);

    // QuadratureRule for the integral of the L^2 error
    QuadratureRuleKey quadKey(dim,6);

    // Compute the embedded L^2 error
    double l2Error = DiscretizationError<GridView>::computeL2Error(&numericalSolution,
                                                                   referenceSolution.get(),
                                                                   quadKey);

    // Compute the embedded H^1 error
    double h1Error = DiscretizationError<GridView>::computeH1HalfNormDifferenceSquared(gridView,
                                                                                       &numericalSolution,
                                                                                       referenceSolution.get(),
                                                                                       quadKey);

    std::cout << "elements: " << gridView.size(0)
              << "      "
              << "L^2 error: " << l2Error
              << "      ";
    std::cout << "H^1 error: " << std::sqrt(l2Error*l2Error + h1Error) << std::endl;
  }

  if (parameterSet.get<std::string>("discretizationErrorMode")=="discrete")
  {
    FEBasis referenceFEBasis(referenceGridView);

    // Reference configuration
    EmbeddedVectorType embeddedReferenceX(referenceFEBasis.size());
    inFile.open(parameterSet.get<std::string>("referenceData"), std::ios_base::binary);
    if (not inFile)
      DUNE_THROW(IOError, "File " << parameterSet.get<std::string>("referenceData") << " could not be opened.");
    GenericVector::readBinary(inFile, embeddedReferenceX);

    SolutionType referenceX(embeddedReferenceX.size());
    for (size_t i=0; i<referenceX.size(); i++)
      referenceX[i] = TargetSpace(embeddedReferenceX[i]);

    using FufemFEBasis = DuneFunctionsBasis<FEBasis>;
    FufemFEBasis fufemReferenceFEBasis(referenceFEBasis);
    FufemFEBasis fufemFEBasis(feBasis);

    // The numerical solution, as a grid function
    GFE::EmbeddedGlobalGFEFunction<FufemFEBasis, TargetSpace> referenceSolution(fufemReferenceFEBasis, referenceX);

    // The numerical solution, as a grid function
    GFE::EmbeddedGlobalGFEFunction<FufemFEBasis, TargetSpace> numericalSolution(fufemFEBasis, x);

    double l2ErrorSquared = 0;
    double h1ErrorSquared = 0;

    HierarchicSearch<typename GridView::Grid,typename GridView::IndexSet> hierarchicSearch(gridView.grid(), gridView.indexSet());

    std::cout << "l2: " << l2ErrorSquared << std::endl;
    for (const auto& rElement : elements(referenceGridView))
    {
      const auto& quadRule = QuadratureRules<double, dim>::rule(rElement.type(), 6);

      for (const auto& qp : quadRule)
      {
        auto integrationElement = rElement.geometry().integrationElement(qp.position());

        auto globalPos = rElement.geometry().global(qp.position());

        auto element = hierarchicSearch.findEntity(globalPos);
        auto localPos = element.geometry().local(globalPos);

        auto diff = referenceSolution(rElement, qp.position()) - numericalSolution(element, localPos);

        l2ErrorSquared += integrationElement * qp.weight() * diff.two_norm2();

        auto derDiff = referenceSolution.derivative(rElement, qp.position()) - numericalSolution.derivative(element, localPos);

        h1ErrorSquared += integrationElement * qp.weight() * derDiff.frobenius_norm2();

      }
    }
    std::cout << "l2: " << l2ErrorSquared << std::endl;

    std::cout << "levels: " << gridView.grid().maxLevel()+1
              << "      "
              << "L^2 error: " << std::sqrt(l2ErrorSquared)
              << "      "
              << "H^1 error: " << std::sqrt(l2ErrorSquared + h1ErrorSquared)
              << std::endl;
  }
}


int main (int argc, char *argv[]) try
{
  // Start Python interpreter
  Python::start();
  Python::Reference main = Python::import("__main__");
  Python::run("import math");

  Python::runStream()
      << std::endl << "import sys"
      << std::endl << "sys.path.append('/home/sander/dune/dune-gfe/problems')"
      << std::endl;

  // parse data file
  ParameterTree parameterSet;
  if (argc < 2)
    DUNE_THROW(Exception, "Usage: ./compute-disc-error <parameter file>");

  ParameterTreeParser::readINITree(argv[1], parameterSet);

  ParameterTreeParser::readOptions(argc, argv, parameterSet);

  // Print all parameters, to have them in the log file
  parameterSet.report();

  /////////////////////////////////////////
  //    Create the grids
  /////////////////////////////////////////
  typedef UGGrid<dim> GridType;

  const int numLevels = parameterSet.get<int>("numLevels");

  shared_ptr<GridType> grid, referenceGrid;

  FieldVector<double,dimworld> lower(0), upper(1);

  if (parameterSet.get<bool>("structuredGrid"))
  {
    lower = parameterSet.get<FieldVector<double,dimworld> >("lower");
    upper = parameterSet.get<FieldVector<double,dimworld> >("upper");

    array<unsigned int,dim> elements = parameterSet.get<array<unsigned int,dim> >("elements");
    grid = StructuredGridFactory<GridType>::createCubeGrid(lower, upper, elements);
    referenceGrid = StructuredGridFactory<GridType>::createCubeGrid(lower, upper, elements);
  }
  else
  {
    std::string path                = parameterSet.get<std::string>("path");
    std::string gridFile            = parameterSet.get<std::string>("gridFile");
    grid = shared_ptr<GridType>(GmshReader<GridType>::read(path + "/" + gridFile));
    referenceGrid = shared_ptr<GridType>(GmshReader<GridType>::read(path + "/" + gridFile));
  }

  grid->globalRefine(numLevels-1);
  referenceGrid->globalRefine(parameterSet.get<int>("numReferenceLevels")-1);

  // Do the actual measurement
  const int order = parameterSet.get<int>("order");
  switch (order)
  {
    case 1:
    measureEOC<GridType::LeafGridView,1>(grid->leafGridView(), referenceGrid->leafGridView(), parameterSet);
    break;

    case 2:
    measureEOC<GridType::LeafGridView,2>(grid->leafGridView(), referenceGrid->leafGridView(), parameterSet);
    break;

    case 3:
    measureEOC<GridType::LeafGridView,3>(grid->leafGridView(), referenceGrid->leafGridView(), parameterSet);
    break;

    default:
      DUNE_THROW(NotImplemented, "Order '" << order << "' is not implemented");
  }

  return 0;
}
catch (Exception e)
{
  std::cout << e << std::endl;
  return 1;
}