// ============================================================================
// ==                                                                        ==
// == 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 MeshStructure.h */

#ifndef AMDIS_MESH_STRUCTURE_H
#define AMDIS_MESH_STRUCTURE_H

#include <vector>
#include "AMDiS_fwd.h"
#include "Global.h"
#include "parallel/InteriorBoundary.h"

namespace AMDiS {

  class MeshStructure
  {
  public:
    MeshStructure()
      : currentIndex(0),
	currentCode(0),
	pos(0),
	currentElement(0),
	nElements(0),
	debugMode(false)
    {}
  
    void clear();

    /// Creates a mesh structure code from a mesh object by traversing it in preorder.
    void init(Mesh *mesh);
   
    void init(BoundaryObject &bound);

    void init(const std::vector<unsigned long int>& initCode, int n) 
    {
      code = initCode;
      nElements = n;
      reset();
    }

    /** \brief
     * Sets all position counters, that are used to traverse the code, to the starting
     * position. The code itself is not changed.
     */
    void reset();

    /// Returns whether the code is empty or not.
    inline bool empty()
    {
      return (nElements == 0);
    }

    inline void commit() 
    {
      if (pos > 0)
	code.push_back(currentCode);
      reset();
    }

    bool skipBranch(MeshStructure *insert = NULL);

    ElInfo *skipBranch(ElInfo *elInfo, TraverseStack *stack);

    bool nextElement(MeshStructure *insert = NULL);

    inline bool isLeafElement() 
    {
      return (currentCode & 1) == 0;
    }

    /** \brief
     * Merges a mesh structure code with its own mesh structure code. The result
     * overwrites the own mesh structure code.
     */
    void merge(MeshStructure *struc) 
    {
      MeshStructure temp(*this);
      merge(&temp, struc, this);
    }

    /** \brief
     * Fits a given mesh to the mesh structure code. 
     *
     * \param debugMode   In debugMode, the whole mesh is fitted to the mesh structure
     *                    code. Otherwise, the mesh is fitted only on the partition
     *                    of the current process.
     */
    void fitMeshToStructure(Mesh *mesh,
			    RefinementManager *manager,
			    bool checkPartition = false,
			    bool debugMode = false);

    /// Prints the mesh structure code.
    void print() 
    {
      FUNCNAME("MeshStructure::print()");

      std::stringstream oss;

      if (empty()) {
	oss << "-" << std::endl;
      }	else {	
	reset();
	bool cont = true;
	while (cont) {
	  if (isLeafElement())
	    oss << "0";
	  else
	    oss << "1";
	  
	  cont = nextElement();
	}
      }

      MSG("Mesh structure code: %s\n", oss.str().c_str());
    }

    /// Returns the mesh structure code.
    inline const std::vector<unsigned long int>& getCode() 
    {
      return code;
    }

    inline int getNumElements() 
    { 
      return nElements; 
    }

    inline int getCurrentElement() 
    {
      return currentElement;
    }

    void setDebugMode(bool b)
    {
      debugMode = b;
    }

    /// Returns true, if the given mesh structure code is equal to this one.
    bool compare(MeshStructure &other);

  protected:
    /// Insert a new element to the structure code. Is used by the init function.
    void insertElement(bool isLeaf);

    void addAlongSide(Element *el, GeoIndex subObj, int ithObj, int elType, bool reverseOrder);

    /// Merges two mesh structure codes to one structure code.     
    void merge(MeshStructure *structure1,
	       MeshStructure *structure2,
	       MeshStructure *result);

  protected:
    /// Mesh structure code.
    std::vector<unsigned long int> code;

    int currentIndex;

    unsigned long int currentCode;

    int pos;

    int currentElement;

    int nElements;

    /// If true, some output is printed to screen during mesh structure code generation.
    bool debugMode;

    static const int unsignedLongSize;
  };

}

#endif