// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  TU Dresden                                                            ==
// ==                                                                        ==
// ==  Institut für Wissenschaftliches Rechnen                               ==
// ==  Zellescher Weg 12-14                                                  ==
// ==  01069 Dresden                                                         ==
// ==  germany                                                               ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  https://gforge.zih.tu-dresden.de/projects/amdis/                      ==
// ==                                                                        ==
// ============================================================================

/** \file InteriorBoundary.h */

#ifndef AMDIS_INTERIORBOUNDARY_H
#define AMDIS_INTERIORBOUNDARY_H

#include <vector>
#include <map>

#include "AMDiS_fwd.h"
#include "MacroElement.h"
#include "Element.h"

namespace AMDiS {

  typedef std::vector<std::pair<GeoIndex, int> > ExcludeList;

  /// Defines the geometrical objects that forms the boundary;
  struct BoundaryObject {

    BoundaryObject()
      : reverseMode(false),
	excludedSubstructures(0)
    {}

    BoundaryObject(Element *e, int eType, GeoIndex sObj, int iObj)
      : el(e),
	elIndex(e->getIndex()),
	elType(eType),
	subObj(sObj),
	ithObj(iObj),
	reverseMode(false),
	excludedSubstructures(0)
    {}

    void setReverseMode(BoundaryObject &otherBound, FiniteElemSpace *feSpace);

    bool operator==(const BoundaryObject& other) const;
    
    bool operator!=(const BoundaryObject& other) const;

    /// The macro element to which the boundary element corresponds to.
    Element* el;

    /// Index of the macro element.
    int elIndex;

    /// Element type index, only used in 3d.
    int elType;

    /** \brief
     * Defines the geometrical object at the boundary. It must be "a part" of the
     * macro element \ref el, i.e., either 1 (a vertex), 2 (an edge) or 3 (a face).
     */
    GeoIndex subObj;

    /** \brief
     * Defines which of vertix, edge or face of the macro element is part of the
     * boundary.
     *
     * Example: If the macro element is a triangle, than \ref subObj may be either
     * 1 (vertex) or 2 (edge). Assume its the last one. So this variable defines
     * which of the three possible edges of the triangle is at the interior
     * boundary.
     */
    int ithObj;

    bool reverseMode;

    /** \brief
     * In many situations it may be necessary to exclude some parts of the element to
     * be part of the boundary. In 3d, when a face is part of the boundary, an edge or
     * an vertex may be exludeded. In 2d only vertices may be exluded to be part of
     * an edge boundary. This list contains pairs of exludeded structures. The first
     * component of every pair denotes if it is a vertex or an edge, and the second
     * component denotes the local index of the structure.
     */
    ExcludeList excludedSubstructures;
  };

  /** \brief 
   * Defines one atomic part of the boundary, i.e., two boundary objects where the
   * boundary goes through.
   */
  struct AtomicBoundary {
    /// The rank's part of the boundary.
    BoundaryObject rankObj;

    /// The object on the other side of the boundary.
    BoundaryObject neighObj;
  };

  /** \brief
   * Defines the interior boundary, i.e. a bound within the domain. It is used for
   * the classical domain decomposition parallelization.
   */
  class InteriorBoundary {
  public:
    typedef std::map<int, std::vector<AtomicBoundary> > RankToBoundMap;

    /// Iterator for the interior boundary object.
    class iterator {      
    public:
      iterator(InteriorBoundary &b)
	: bound(b)
      {
	reset();
      }

      /// Set the iterator to the first position.
      void reset()
      {
	mapIt = bound.boundary.begin();
	nextNonempty();

	if (mapIt != bound.boundary.end())
	  vecIt = mapIt->second.begin();	
      }

      /// Test if iterator is at the final position.
      bool end() const
      {
	return (mapIt == bound.boundary.end());
      }

      /// Move iterator to the next position.
      void operator++()
      {
	++vecIt;
	if (vecIt == mapIt->second.end()) {
	  ++mapIt;
	  nextNonempty();

	  if (mapIt != bound.boundary.end())
	    vecIt = mapIt->second.begin();	  
	}	
      }

      void nextRank()
      {
	++mapIt;
	nextNonempty();

	if (mapIt != bound.boundary.end())
	  vecIt = mapIt->second.begin();	
      }

      int getRank() 
      {
	return mapIt->first;
      }

      AtomicBoundary& getBound()
      {
	return *vecIt;
      }

    protected:

      inline void nextNonempty()
      {
 	while (mapIt->second.size() == 0) {
 	  ++mapIt;
	  if (mapIt == bound.boundary.end())
	    return;
	}
      }

    protected:
      RankToBoundMap::iterator mapIt;

      std::vector<AtomicBoundary>::iterator vecIt;

      InteriorBoundary &bound;
    };

  public:
    InteriorBoundary() {}

    AtomicBoundary& getNewAtomic(int rank);

    /// Writes this object to a file.
    void serialize(std::ostream &out);

    /// Reads the state of an interior boundary from a file.
    void deserialize(std::istream &in, std::map<int, Element*> &elIndexMap);

  protected:
    void serializeExcludeList(std::ostream &out, ExcludeList &list);

    void deserializeExcludeList(std::istream &in, ExcludeList &list);

  public:
    RankToBoundMap boundary;
  };
}

#endif // AMDIS_INTERIORBOUNDARY_H