// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  crystal growth group                                                  ==
// ==                                                                        ==
// ==  Stiftung caesar                                                       ==
// ==  Ludwig-Erhard-Allee 2                                                 ==
// ==  53175 Bonn                                                            ==
// ==  germany                                                               ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  http://www.caesar.de/cg/AMDiS                                         ==
// ==                                                                        ==
// ============================================================================

/** \file ParallelDomain.h */

#ifndef AMDIS_PARALLELDOMAIN_H
#define AMDIS_PARALLELDOMAIN_H

#include <map>
#include <set>
#include <vector>

#include "ProblemTimeInterface.h"
#include "ProblemIterationInterface.h"
#include "FiniteElemSpace.h"
#include "AdaptInfo.h"
#include "InteriorBoundary.h"
#include "AMDiS_fwd.h"

#include "petsc.h"
#include "petscsys.h"
#include "petscao.h"
#include "mpi.h"

namespace AMDiS {

  class ParMetisPartitioner;

  class ParallelDomainBase : public ProblemIterationInterface,
                                    public ProblemTimeInterface
  {
  private:
    /// Defines type for a vector of DOFs.
    typedef std::vector<const DegreeOfFreedom*> DofContainer;

    /// Defines a mapping type from DOFs to rank numbers.
    typedef std::map<const DegreeOfFreedom*, int> DofToRank;

    /// Defines a mapping type from DOFs to a set of rank numbers.
    typedef std::map<const DegreeOfFreedom*, std::set<int> > DofToPartitions;

    /// Defines a mapping type from rank numbers to sets of DOFs.
    typedef std::map<int, DofContainer> RankToDofContainer;

    /// Defines a mapping type from DOF indices to DOF indices.
    typedef std::map<DegreeOfFreedom, DegreeOfFreedom> DofMapping;

    /// Defines a mapping type from DOF indices to boolean values.
    typedef std::map<DegreeOfFreedom, bool> DofToBool;

    /// Defines a mapping type from rank numbers to sets of coordinates.
    typedef std::map<int, std::vector<WorldVector<double> > > RankToCoords;

    /// Forward type (it maps rank numbers to the interior boundary objects).
    typedef InteriorBoundary::RankToBoundMap RankToBoundMap;

  public:
    ParallelDomainBase(const std::string& name,
		       ProblemIterationInterface *iterationIF,
		       ProblemTimeInterface *timeIF,
		       FiniteElemSpace *feSpace,
		       RefinementManager *refineManager);

    virtual ~ParallelDomainBase() {}

    virtual void initParallelization(AdaptInfo *adaptInfo);

    void exitParallelization(AdaptInfo *adaptInfo);

    /** \brief
     * Test, if the mesh consists of macro elements only. The mesh partitioning of
     * the parallelization works for macro meshes only and would fail, if the mesh
     * is already refined in some way. Therefore, this function will exit the program
     * if it finds a non macro element in the mesh.
     */
    void testForMacroMesh();

    /// Set for each element on the partitioning level the number of leaf elements.
    double setElemWeights(AdaptInfo *adaptInfo);

    void partitionMesh(AdaptInfo *adaptInfo);

    virtual void setTime(AdaptInfo *adaptInfo) {}

    virtual void initTimestep(AdaptInfo *adaptInfo) {}

    virtual void closeTimestep(AdaptInfo *adaptInfo) {}

    virtual void solveInitialProblem(AdaptInfo *adaptInfo) {}
  
    virtual void transferInitialSolution(AdaptInfo *adaptInfo) {}

    virtual void beginIteration(AdaptInfo *adaptInfo) 
    {
      iterationIF->beginIteration(adaptInfo);
    }

    virtual Flag oneIteration(AdaptInfo *adaptInfo, Flag toDo = FULL_ITERATION) 
    {
      ERROR_EXIT("Not implemented!\n");
      return 0;
    }

    virtual void endIteration(AdaptInfo *adaptInfo) 
    {
      iterationIF->endIteration(adaptInfo);
    }

    virtual int getNumProblems() 
    {
      return 0;
    }

    inline virtual const std::string& getName() 
    { 
      return name; 
    }

    /// Returns \ref nRankDOFs, the number of DOFs in the rank mesh.
    int getNumberRankDOFs() 
    {
      return nRankDOFs;
    }

    void fillPetscMatrix(DOFMatrix *mat, DOFVector<double> *vec);

    void solvePetscMatrix(DOFVector<double> *vec);

    virtual ProblemStatBase *getProblem(int number = 0) 
    {
      return NULL;
    }

    virtual void serialize(std::ostream&) {}

    virtual void deserialize(std::istream&) {}


  protected:
    /** \brief
     * Determine the interior boundaries, i.e. boundaries between ranks, and store
     * all information about them in \ref interiorBoundary.
     */
    void createInteriorBoundaryInfo(DofContainer& rankDOFs,
				    DofToRank& boundaryDOFs);

    /// Removes all macro elements from the mesh that are not part of ranks partition.
    void removeMacroElements();


    /** \brief
     * Creates from a macro mesh a correct local and global DOF index numbering.
     *
     * \param[out] rankDOFs      Returns all DOFs from the macro mesh, which are owned
     *                           by the rank after partitioning the macro mesh.
     * \param[out] boundaryDOFs  Returns all DOFs from the macro mesh, which lies at
     *                           an interior boundary of the rank. This object maps
     *                           each such DOF to the rank that owns this DOF.
     * \param[out] nRankDOFs     Number of DOFs owned by rank.
     * \param[out] nOverallDOFs  Number of all DOFs in macro mesh.
     */
    void createLocalGlobalNumbering(DofContainer& rankDOFs,
				    DofToRank& boundaryDOFs,
				    int& nRankDOFs, 
				    int& nOverallDOFs);

    void updateLocalGlobalNumbering(int& nRankDOFs, int& nOverallDOFs);

    void addAllVertexDOFs(Element *el, int ithEdge, DofContainer& dofs);

    void addAllEdgeDOFs(Element *el, int ithEdge, DofContainer& dofs);

    /** \brief
     * This function traverses the whole mesh, i.e. before it is really partitioned,
     * and collects information about which DOF corresponds to which rank. Can only
     * be used, if \ref partitionVec is set correctly. This is only the case, when
     * the macro mesh is partitioned.
     *
     * \param[out] partionDOFs   Stores to each DOF pointer the set of ranks the DOF is
     *                           part of.
     * \param[out] rankDOFs      Stores all rank DOFs.
     * \param[out] boundaryDOFs  Stores all DOFs in ranks partition that are on an 
     *                           interior boundary but correspond to another rank.
     */
    void createDOFMemberInfo(DofToPartitions& partitionDOFs,
			     DofContainer& rankDOFs,
			     DofToRank& boundaryDOFs);


    void DbgTestInteriorBoundary();
     
    /** \brief
     * This function is used for debugging only. It traverses all interior boundaries
     * and compares the dof indices on them with the dof indices of the boundarys
     * neighbours. The function fails, when dof indices on an interior boundary does
     * not fit together.
     */
    void DbgTestCommonDofs();

  protected:
    ///
    ProblemIterationInterface *iterationIF;

    ///
    ProblemTimeInterface *timeIF;

    /// The rank of the current process.
    int mpiRank;

    /// Overall number of processes.
    int mpiSize;

    /** \brief
     * MPI communicator collected all processes, which should
     * be used for calculation. The Debug procces is not included
     * in this communicator.
     */
    MPI::Intracomm mpiComm;

    /// Name of the problem (as used in the init files)
    std::string name;

    /// Finite element space of the problem.
    FiniteElemSpace *feSpace;

    /// Mesh of the problem.
    Mesh *mesh;

    /// Info level.
    int info;

    /// Refinement manager for the mesh.
    RefinementManager *refinementManager;

    /// Pointer to the paritioner which is used to devide a mesh into partitions.
    ParMetisPartitioner *partitioner;

    /// Weights for the elements, i.e., the number of leaf elements within this element.
    std::map<int, double> elemWeights;

    /// Is true, if the mesh was not partitioned before, otherwise it's false.
    bool initialPartitionMesh;

    /** \brief
     * Stores to every coarse element index the number of the partition it 
     * corresponds to.
     */
    std::map<int, int> partitionVec;

    /** \brief
     * Stores an old partitioning of elements. To every element index the number
     * of the parition it corresponds to is stored.
     */
    std::map<int, int> oldPartitionVec;    

    Mat petscMatrix;

    Vec petscRhsVec;
    
    Vec petscSolVec;

    /// Number of DOFs in the rank mesh.
    int nRankDOFs;

    /** \brief
     * Set of all interior boundary DOFs in ranks partition. The object maps to
     * each such DOF to the number of the rank that owns this DOF.
     */
    DofToRank boundaryDOFs;

    /** \brief 
     * Defines the interior boundaries of the domain that result from partitioning
     * the whole mesh. Contains only the boundaries, which are owned by the rank, i.e.,
     * the object gives for every neighbour rank i the boundaries this rank owns and 
     * shares with rank i.
     */
    InteriorBoundary myIntBoundary;
    
    /** \brief
     * Defines the interior boundaries of the domain that result from partitioning
     * the whole mesh. Contains only the boundaries, which are not owned by the rank,
     * i.e., the object gives for every neighbour rank i the boundaries that are
     * owned by rank i and are shared with this rank.
     */
    InteriorBoundary otherIntBoundary;

    /** \brief
     * This map contains for each rank the list of dofs the current rank must send
     * to exchange solution dofs at the interior boundaries.
     */
    RankToDofContainer sendDofs;

    /** \brief
     * This map contains for each rank the list of dofs from which the current rank 
     * must receive solution values of dofs at the interior boundaries.
     */
    RankToDofContainer recvDofs;

    /// Maps local to global dof indices.
    DofMapping mapLocalGlobalDOFs;

    /// Maps global to local dof indices.
    DofMapping mapGlobalLocalDOFs;

    /** \brief
     * Maps all DOFs in ranks partition to a bool value. If it is true, the DOF is
     * owned by the rank. Otherwise, its an interior boundary DOF that is owned by
     * another rank.
     */
    DofToBool isRankDOF;
  };

  class ParallelDomainScal : public ParallelDomainBase
  {
  public:
    ParallelDomainScal(const std::string& name,
			      ProblemScal *problem,
			      ProblemInstatScal *problemInstat);

    void initParallelization(AdaptInfo *adaptInfo);

    virtual Flag oneIteration(AdaptInfo *adaptInfo, Flag toDo = FULL_ITERATION);

  protected:
    /// Starts the solution of the linear system using Petsc.
    void solve();

  protected:
    /// Pointer to the stationary problem.
    ProblemScal *probScal;
  };
}

#endif // AMDIS_PARALLELDOMAIN_H