// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ==  http://www.amdis-fem.org                                              ==
// ==                                                                        ==
// ============================================================================
//
// Software License for AMDiS
//
// Copyright (c) 2010 Dresden University of Technology 
// All rights reserved.
// Authors: Simon Vey, Thomas Witkowski et al.
//
// This file is part of AMDiS
//
// See also license.opensource.txt in the distribution.



/** \file MeshDistributor.h */

#ifndef AMDIS_MESHDISTRIBUTOR_H
#define AMDIS_MESHDISTRIBUTOR_H


#include <mpi.h>
#include "parallel/ParallelTypes.h"
#include "parallel/MeshPartitioner.h"
#include "parallel/InteriorBoundary.h"
#include "AMDiS_fwd.h"
#include "Global.h"
#include "ProblemTimeInterface.h"
#include "ProblemIterationInterface.h"
#include "FiniteElemSpace.h"
#include "Serializer.h"
#include "BoundaryManager.h"
#include "ElementObjectData.h"
#include "SystemVector.h"

namespace AMDiS {

  using namespace std;


  struct BoundaryDofInfo
  {
    map<GeoIndex, DofContainerSet> geoDofs;
  };
  

  class MeshDistributor
  {
  public:
    MeshDistributor();
		          
    virtual ~MeshDistributor() {}

    void initParallelization();

    void exitParallelization();

    void addProblemStat(ProblemStatSeq *probStat);

    /// Adds a DOFVector to the set of \ref interchangeVecs. Thus, this vector will
    /// be automatically interchanged between ranks when mesh is repartitioned.
    void addInterchangeVector(DOFVector<double> *vec)
    {
      interchangeVectors.push_back(vec);
    }

    /// Adds all DOFVectors of a SystemVector to \ref interchangeVecs.
    void addInterchangeVector(SystemVector *vec)
    {
      for (int i = 0; i < vec->getSize(); i++)
	interchangeVectors.push_back(vec->getDOFVector(i));
    }
    
    /** \brief
     * This function checks if the mesh has changed on at least on rank. In this case,
     * the interior boundaries are adapted on all ranks such that they fit together on
     * all ranks. Furthermore the function \ref updateLocalGlobalNumbering() is called
     * to update the DOF numberings and mappings on all rank due to the new mesh
     * structure.
     *
     * \param[in]  tryRepartition   If this parameter is true, repartitioning may be
     *                              done. This depends on several other parameters. If
     *                              the parameter is false, the mesh is only checked
     *                              and adapted but never repartitioned.
     */
    void checkMeshChange(bool tryRepartition = true);

    /** \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.
    void setInitialElementWeights();

    inline virtual string getName() 
    { 
      return name; 
    }

    inline Mesh* getMesh()
    {
      return mesh;
    }

    /// Returns \ref feSpace.
    inline const FiniteElemSpace* getFeSpace()
    {
      return feSpace;
    }
    
    /// Returns \ref nRankDOFs, the number of DOFs in the rank mesh.
    inline int getNumberRankDofs() 
    {
      return nRankDofs;
    }

    /// Returns \ref nOverallDofs, the global number of DOFs.
    inline int getNumberOverallDofs()
    {
      return nOverallDofs;
    }

    inline DofMapping& getMapLocalGlobalDofs()
    {
      return mapLocalGlobalDofs;
    }

    /// Maps a local DOF to its global index.
    inline DegreeOfFreedom mapLocalToGlobal(DegreeOfFreedom dof)
    {
      return mapLocalGlobalDofs[dof];
    }

    DegreeOfFreedom mapGlobalToLocal(DegreeOfFreedom dof);

    /// Maps a local DOF to its local index.
    inline DegreeOfFreedom mapLocalToDofIndex(DegreeOfFreedom dof)
    {
      return mapLocalDofIndex[dof];
    }

    /// Returns the periodic mapping for all boundary DOFs in rank.
    inline PeriodicDofMap& getPeriodicMapping()
    {
      return periodicDof;
    }

    /// Returns for a global dof index its periodic mapping for a given boundary type.
    inline int getPeriodicMapping(int globalDofIndex, BoundaryType type)
    {
      FUNCNAME("MeshDistributor::getPeriodicMapping()");

      TEST_EXIT_DBG(periodicDof[type].count(globalDofIndex) == 1)
	("There is no periodic association for global DOF %d for boundary type %d!\n",
	 globalDofIndex, type);

      return periodicDof[type][globalDofIndex];
    }

    /// For a given global DOF index, this function returns the set of periodic
    /// associations, i.e., the boundary types the DOF is associated to, for this DOF.
    inline std::set<BoundaryType>& getPerDofAssociations(int globalDofIndex)
    {      
      TEST_EXIT_DBG(periodicDofAssociations.count(globalDofIndex)) 
 	("Should not happen!\n"); 

      return periodicDofAssociations[globalDofIndex];
    }

    /// Returns true, if the DOF (global index) is a periodic DOF.
    inline bool isPeriodicDof(int globalDofIndex)
    {
      return (periodicDofAssociations.count(globalDofIndex) > 0 &&
	       periodicDofAssociations[globalDofIndex].size() > 0);
    }

    /// Returns true, if the DOF (global index) is a periodic DOF for the given
    /// boundary type.
    inline bool isPeriodicDof(int globalDofIndex, BoundaryType type)
    {
      return (periodicDof[type].count(globalDofIndex) > 0);
    }

    /// Return true, if the given DOF is owned by the rank. If false, the DOF is in
    /// rank's partition, but is owned by some other rank.
    inline bool getIsRankDof(DegreeOfFreedom dof)
    {
      if (isRankDof.count(dof))
	return isRankDof[dof];

      return false;
    }

    inline DofIndexToBool& getIsRankDof()
    {
      return isRankDof;
    }

    inline long getLastMeshChangeIndex()
    {
      return lastMeshChangeIndex;
    }

    inline int getRstart()
    {
      return rstart;
    }

    inline int getMpiRank()
    {
      return mpiRank;
    }

    inline int getMpiSize()
    {
      return mpiSize;
    }

    inline MPI::Intracomm& getMpiComm()
    {
      return mpiComm;
    }

    inline RankToDofContainer& getSendDofs()
    {
      return sendDofs;
    }

    inline RankToDofContainer& getRecvDofs()
    {
      return recvDofs;
    }

    // Writes all data of this object to an output stream.
    void serialize(ostream &out);

    // Reads the object data from an input stream.
    void deserialize(istream &in);

    /** \brief
     * This function must be used if the values of a DOFVector must be synchronised
     * over all ranks. That means, that each rank sends the values of the DOFs, which
     * are owned by the rank and lie on an interior bounday, to all other ranks also
     * having these DOFs.
     *
     * This function must be used, for example, after the lineary system is solved, or
     * after the DOFVector is set by some user defined functions, e.g., initial
     * solution functions.
     */    
    void synchVector(DOFVector<double> &vec);

    /** \brief
     * Works in the same way as the function above defined for DOFVectors. Due to
     * performance, this function does not call \ref synchVector for each DOFVector,
     * but instead sends all values of all DOFVectors all at once.
     */
    void synchVector(SystemVector &vec);

    void check3dValidMesh();

    void setBoundaryDofRequirement(Flag flag)
    {
      createBoundaryDofFlag = flag;
    }

    BoundaryDofInfo& getBoundaryDofInfo()
    {
      return boundaryDofInfo;
    }

    void getAllBoundaryDofs(DofContainer& dofs);

  protected:
    /** \brief
     * Determines the interior boundaries, i.e. boundaries between ranks, and stores
     * all information about them in \ref interiorBoundary.
     */
    void createInteriorBoundaryInfo();

    void updateInteriorBoundaryInfo();

    void createMeshElementData();

    void createBoundaryData();

    void createBoundaryDofs();

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

    /// Updates the local and global DOF numbering after the mesh has been changed.
    void updateLocalGlobalNumbering();

    /** \brief
     * Creates to all dofs in rank's partition that are on a periodic boundary the
     * mapping from dof index to the other periodic dof indices. This information
     * is stored in \ref periodicDof.
     */
    void createPeriodicMap();

    void createMacroElementInfo();

    void updateMacroElementInfo();

    /** \brief
     * Checks for all given interior boundaries if the elements fit together on both
     * sides of the boundaries. If this is not the case, the mesh is adapted. Because
     * refinement of a certain element may forces the refinement of other elements,
     * it is not guaranteed that all rank's meshes fit together after this function
     * terminates. Hence, it must be called until a stable mesh refinement is reached.
     *
     * \param[in] allBound   Defines a map from rank to interior boundaries which 
     *                       should be checked.
     *
     * \return    If the mesh has  been changed by this function, it returns true. 
     *            Otherwise, it returns false, i.e., the given interior boundaries 
     *            fit together on both sides.
     */
    bool checkAndAdaptBoundary(RankToBoundMap &allBound);
  
    /** \brief
     * Checks if is required to repartition the mesh. If this is the case, a new
     * partition will be created and the mesh will be redistributed between the
     * ranks.
     */
    void repartitionMesh();

    /// Sets \ref isRankDof to all matrices and rhs vectors in a given 
    /// stationary problem.
    void setRankDofs(ProblemStatSeq *probStat);

    /// Sets \ref isRankDof to all matrices and rhs vectors in all stationary problems.
    void setRankDofs();

    /// Removes all periodic boundary condition information from all matrices and
    /// vectors of all stationary problems and from the mesh itself.
    void removePeriodicBoundaryConditions();

    // Removes all periodic boundaries from a given boundary map.
    void removePeriodicBoundaryConditions(BoundaryIndexMap& boundaryMap);

    /// Writes a vector of dof pointers to an output stream.
    void serialize(ostream &out, DofContainer &data);

    /// Reads a vector of dof pointers from an input stream.
    void deserialize(istream &in, DofContainer &data,
		     map<int, const DegreeOfFreedom*> &dofMap);

    /// Writes a \ref RankToDofContainer to an output stream.
    void serialize(ostream &out, RankToDofContainer &data);

    /// Reads a \ref RankToDofContainer from an input stream.
    void deserialize(istream &in, RankToDofContainer &data,
		     map<int, const DegreeOfFreedom*> &dofMap);

    /// Writes a periodic dof mapping to an output stream.
    void serialize(ostream &out, PeriodicDofMap &data);

    void serialize(ostream &out, map<int, std::set<int> >& data);

    /// Reads a periodic dof mapping from an input stream.
    void deserialize(istream &in, PeriodicDofMap &data);

    void deserialize(istream &in, map<int, std::set<int> >& data);

    /// Writes a mapping from dof pointers to some values to an output stream.
    template<typename T>
    void serialize(ostream &out, map<const DegreeOfFreedom*, T> &data)
    {
      FUNCNAME("ParallelDomainBase::serialize()");

      int mapSize = data.size();
      SerUtil::serialize(out, mapSize);
      for (typename map<const DegreeOfFreedom*, T>::iterator it = data.begin();
	   it != data.end(); ++it) {
	int v1 = (*(it->first));
	T v2 = it->second;
	SerUtil::serialize(out, v1);
	SerUtil::serialize(out, v2);
      }
    }

    /// Reads a mapping from dof pointer to some values from an input stream.
    template<typename T>
    void deserialize(istream &in, map<const DegreeOfFreedom*, T> &data,
		     map<int, const DegreeOfFreedom*> &dofMap)
    {
      FUNCNAME("ParallelDomainBase::deserialize()");

      int mapSize = 0;
      SerUtil::deserialize(in, mapSize);
      for (int i = 0; i < mapSize; i++) {
	int v1 = 0;
	T v2;
	SerUtil::deserialize(in, v1);
	SerUtil::deserialize(in, v2);

	TEST_EXIT_DBG(dofMap.count(v1) != 0)("Cannot find DOF %d in map!\n", v1);

	data[dofMap[v1]] = v2;
      }
    }

  protected:
    /// List of all stationary problems that are managed by this mesh distributor.
    vector<ProblemStatSeq*> problemStat;

    /// If true, the mesh distributor is already initialized;
    bool initialized;

    /// 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)
    string name;

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

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

    /** \brief
     * A refinement manager that should be used on the mesh. It is used to refine
     * elements at interior boundaries in order to fit together with elements on the
     * other side of the interior boundary.
     */    
    RefinementManager *refineManager;

    /// Info level.
    int info;

    /// Pointer to a mesh partitioner that is used to partition the mesh to the ranks.
    MeshPartitioner *partitioner;

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

    /** \brief
     * Stores to every macro element index the number of the rank that owns this
     * macro element.
     */
    map<int, int> partitionMap;

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

    /// Number of DOFs in the whole domain.
    int nOverallDofs;

    // Data structure to store all sub-objects of all elements of the macro mesh.
    ElementObjects elObjects;

    // Maps to each macro element index a pointer to the corresponding element.
    map<int, Element*> macroElIndexMap;
    
    // Maps to each macro element index the type of this element.
    map<int, int> macroElIndexTypeMap;

    /** \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
     * Defines the periodic boundaries with other ranks. Periodic boundaries have
     * no owner, as it is the case of interior boundaries.
     */
    InteriorBoundary periodicBoundary;

    /** \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 on each rank the list of DOFs from which the current rank 
     * will receive DOF values (i.e., this are all DOFs at an interior boundary). The
     * DOF indices are given in rank's local numbering.
     */
    RankToDofContainer recvDofs;

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

    /// Maps local dof indices to real dof indices.
    DofMapping mapLocalDofIndex;  

    /** \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.
     */
    DofIndexToBool isRankDof;

    /** \brief
     * If periodic boundaries are used, this map stores, for each periodic boundary
     * type, for all DOFs in rank's partition (that are on periodic boundaries), the 
     * corresponding mapped periodic DOFs. The mapping is defined by using global 
     * dof indices.
     */
    PeriodicDofMap periodicDof;
    
    /** \brief
     * If periodic boundaries are used, this map stores to each periodic DOF in rank's
     * partition the set of periodic boundaries the DOF is associated to. In 2D, most
     * DOFs are only on one periodic boundary. Only, e.g., in a box with all boundaries
     * being periodic, the four corners are associated by two different boundaries.
     */
    map<int, std::set<BoundaryType> > periodicDofAssociations;

    
    /// This set of values must be interchanged between ranks when the mesh is 
    /// repartitioned.
    vector<DOFVector<double>*> interchangeVectors;
		        
    /// Is the index of the first row of the linear system, which is owned by the rank.
    int rstart;

    /** \brief
     * If the problem definition has been read from a serialization file, this 
     * variable is true, otherwise it is false. This variable is used to stop the
     * initialization function, if the problem definition has already been read from
     * a serialization file.
     */
    bool deserialized;

    /// Denotes whether there exists a filewriter for this object.
    bool writeSerializationFile;

    /// If true, it is possible to repartition the mesh during computations.
    bool repartitioningAllowed;

    /// Stores the number of mesh changes that must lie in between to repartitionings.
    int repartitionIthChange;

    /// Counts the number of mesh changes after the last mesh repartitioning was done.
    int nMeshChangesAfterLastRepartitioning;

    /// Countes the number of mesh repartitions that were done. Till now, this 
    /// variable is used only for debug outputs.
    int repartitioningCounter;

    /// Directory name where all debug output files should be written to.
    string debugOutputDir;

    /** \brief
     * Stores the mesh change index. This is used to recognize changes in the mesh 
     * structure (e.g. through refinement or coarsening managers).
     */
    long lastMeshChangeIndex;

    map<int, vector<int> > macroElementNeighbours;

    /// Store all macro elements of the overall mesh, i.e., before the macro mesh is
    /// redistributed for the first time.
    vector<MacroElement*> allMacroElements;

    Flag createBoundaryDofFlag;

    BoundaryDofInfo boundaryDofInfo;
  public:
    /// The boundary DOFs are sorted by subobject entities, i.e., first all
    /// face DOFs, edge DOFs and to the last vertex DOFs will be set to
    /// communication structure vectors, \ref sendDofs and \ref recvDofs.
    static const Flag BOUNDARY_SUBOBJ_SORTED;

    /// When boundary DOFs are created, \ref boundaryDofInfo is filled for
    /// all DOFs that this rank will send to other ranks (thus, rank 
    /// owned DOFs.
    static const Flag BOUNDARY_FILL_INFO_SEND_DOFS;

    /// When boundary DOFs are created, \ref boundaryDofInfo is filled for
    /// all DOFs that this rank will receive from other ranks (thus, DOFs
    /// that are owned by another rank).
    static const Flag BOUNDARY_FILL_INFO_RECV_DOFS;

    friend class ParallelDebug;
  };
}

#endif // AMDIS_MESHDISTRIBUTOR_H