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

/** \file Element.h */

#ifndef AMDIS_ELEMENT_H
#define AMDIS_ELEMENT_H

// ============================================================================
// ===== includes =============================================================
// ============================================================================

#include "Global.h"
#include "RefinementManager.h"
#include "Serializable.h"
#include "ElementData.h"
#include "LeafData.h"

namespace AMDiS {

  // ============================================================================
  // ===== forward declarations =================================================
  // ============================================================================

  class Mesh;
  class DOFAdmin;
  template<typename T> class WorldVector;
  class CoarseningManager;

  template<typename T, GeoIndex d> class FixVec;

#define AMDIS_UNDEFINED  5

  // ============================================================================
  // ===== class Element ========================================================
  // ============================================================================

  /** \ingroup Triangulation 
   * \brief
   * Base class for Line, Triangle, Tetrahedron
   *
   * Elements in AMDiS are always simplices (a simplex is a Line in 1d, a 
   * Triangle in 2d and a Tetrahedron in 3d). 
   * We restrict ourselves here to simplicial meshes, for several reasons:
   * -# A simplex is one of the most simple geometric types and complex domains 
   *    may be approximated by a set of simplices quite easily.
   * -# Simplicial meshes allow local refinement without the need of 
   *    nonconforming meshes (hanging nodes), parametric elements, or mixture of
   *    element types (which is the case for quadrilateral meshes).
   * -# Polynomials of any degree are easily represented on a simplex using 
   *    local (barycentric) coordinates.
   *
   * A Line element and its refinement:
   *
   * <img src="line.png">
   *
   * A Triangle element and its refinement:
   *
   * <img src="triangle.png">
   *
   * A Tetrahedron element and its refinements:
   *
   * <img src="tetrahedron.png">
   */
  class Element : public Serializable
  {
  private:
    /** \brief
     * private standard constructor because an Element must know his Mesh
     */
    Element() {};
  public:
    /** \brief
     * constructs an Element which belongs to Mesh
     */
    Element(Mesh *);

    /** \brief
     * copy constructor
     */
    Element(const Element& old);

    /** \brief
     * destructor
     */ 
    virtual ~Element();

    // ===== getting methods ======================================================

    /** \name getting methods
     * \{
     */

    /** \brief
     * Returns \ref child[0]
     */
    virtual Element* getFirstChild() const {
      return child[0];
    };

    /** \brief
     * Returns \ref child[1]
     */
    virtual Element* getSecondChild() const {
      return child[1];
    };

    /** \brief
     * Returns \ref child[i], i=0,1
     */
    virtual Element* getChild(int i) const {
      FUNCNAME("Element::getChild()");
      TEST_EXIT_DBG(i==0 || i==1)("i must be 0 or 1\n");
      return child[i];
    };

    /** \brief
     * Returns true if Element is a leaf element (\ref child[0] == NULL), returns
     * false otherwise.
     */
    inline const bool isLeaf() const { 
      return (child[0] == NULL); 
    };

    /** \brief
     * Returns \ref dof[i][j] which is the j-th DOF of the i-th node of Element.
     */
    const DegreeOfFreedom getDOF(int i, int j) const { 
      return dof[i][j];
    };

    /** \brief
     * Returns \ref dof[i] which is a pointer to the DOFs of the i-th node.
     */
    const DegreeOfFreedom* getDOF(int i) const {
      return dof[i];
    };

    /** \brief
     * Returns a pointer to the DOFs of this Element
     */
    const DegreeOfFreedom** getDOF() const {
      return const_cast<const DegreeOfFreedom**>(dof);
    };

    /** \brief
     * Returns \ref mesh of Element
     */
    inline Mesh* getMesh() const { 
      return mesh; 
    };

    /** \brief
     * Returns \ref elementData's error estimation, if Element is a leaf element
     * and has leaf data. 
     */
    inline double getEstimation(int row) const
    {
      if (isLeaf()) {
	TEST_EXIT_DBG(elementData)("leaf element without leaf data\n");
	ElementData *ld = elementData->getElementData(ESTIMATABLE);
	TEST_EXIT_DBG(ld)("leaf data not estimatable!\n");

	return dynamic_cast<LeafDataEstimatableInterface*>(ld)->getErrorEstimate(row);
      }	
      
      return 0.0;
    };

    /** \brief
     * Returns Element's coarsening error estimation, if Element is a leaf 
     * element and if it has leaf data and if this leaf data are coarsenable.
     */
    inline double getCoarseningEstimation(int row) {
      if (isLeaf()) {
	TEST_EXIT_DBG(elementData)("leaf element without leaf data\n");
	ElementData *ld = elementData->getElementData(COARSENABLE);
	TEST_EXIT_DBG(ld)("element data not coarsenable!\n");

	return dynamic_cast<LeafDataCoarsenableInterface*>(ld)->getCoarseningErrorEstimate(row);
      }
      
      return 0.0;
    };

    /** \brief
     * Returns region of element if defined, -1 else.
     */
    int getRegion() const;

    /** \brief
     * Returns local vertex number of the j-th vertex of the i-th edge
     */
    virtual int getVertexOfEdge(int i, int j) const = 0; 

    /** \brief
     * Returns local vertex number of the vertexIndex-th vertex of the
     * positionIndex-th part of type position (vertex, edge, face)
     */
    virtual int getVertexOfPosition(GeoIndex position,
				    int      positionIndex,
				    int      vertexIndex) const = 0;

    /** \brief
     *
     */
    virtual int getPositionOfVertex(int side, int vertex) const = 0;

    /** \brief
     *
     */
    virtual int getEdgeOfFace(int face, int edge) const = 0;

    /** \brief
     * Returns the number of parts of type i in this element
     */
    virtual int getGeo(GeoIndex i) const = 0;

    /** \brief
     * Returns Element's \ref mark
     */
    inline const signed char getMark() const { 
      return mark;
    };

    /** \brief
     * Returns \ref newCoord[i]
     */
    double getNewCoord(int j) const;

    /** \brief
     * Returns Element's \ref index
     */
    inline int getIndex() const { 
      return index; 
    };

    /** \brief
     * Returns \ref newCoord
     */
    inline WorldVector<double>* getNewCoord() const { 
      return newCoord; 
    };

    /** \} */

    // ===== setting methods ======================================================

    /** \name setting methods
     * \{
     */

    /** \brief
     * Sets \ref child[0]
     */
    virtual void setFirstChild(Element *aChild) {
      child[0] = aChild;
    };

    /** \brief
     * Sets \ref child[1]
     */
    virtual void setSecondChild(Element *aChild) {
      child[1] = aChild;
    };

    /** \brief
     * Sets \ref elementData of Element
     */
    void setElementData(ElementData* ed) {
      elementData = ed;
    };

    /** \brief
     * Sets \ref newCoord of Element. Needed by refinement, if Element has a
     * boundary edge on a curved boundary.
     */
    inline void setNewCoord(WorldVector<double>* coord) {
      newCoord = coord;
    };

    /** \brief
     * Sets \ref mesh.
     */
    inline void setMesh(Mesh *m) {
      mesh = m;
    };

    /** \brief
     * Sets the pointer to the DOFs of the i-th node of Element
     */
    DegreeOfFreedom* setDOF(int pos, DegreeOfFreedom* p) {
      dof[pos] = p;
      return dof[pos];
    };

    /** \brief
     * Checks whether Element is a leaf element and whether it has leaf data.
     * If the checks don't fail, leaf data's error estimation is set to est.
     */
    inline void setEstimation(double est, int row)
    {
      if (isLeaf()) {
	TEST_EXIT_DBG(elementData)("leaf element without leaf data\n");
	ElementData *ld = elementData->getElementData(ESTIMATABLE);
	TEST_EXIT_DBG(ld)("leaf data not estimatable\n");

	dynamic_cast<LeafDataEstimatableInterface*>(ld)->
	  setErrorEstimate(row, est);
      } else {
	ERROR_EXIT("setEstimation only for leaf elements!\n");
      }
    };

    /** \brief
     * Sets Element's coarsening error estimation, if Element is a leaf element
     * and if it has leaf data and if this leaf data are coarsenable.
     */
    inline void setCoarseningEstimation(double est, int row)
    {
      if (isLeaf()) {
	TEST_EXIT_DBG(elementData)("leaf element without leaf data\n");
	ElementData *ld = elementData->getElementData(COARSENABLE);
	TEST_EXIT_DBG(ld)("leaf data not coarsenable\n");

	dynamic_cast<LeafDataCoarsenableInterface*>(ld)->
	  setCoarseningErrorEstimate(row, est);
      } else {
	ERROR_EXIT("setEstimation only for leaf elements!\n");
      }
    };

    /** \brief
     * Sets Elements \ref mark = mark + 1;
     */
    inline void incrementMark() {
      mark++;
    }

    /** \brief
     * Sets Elements \ref mark = mark - 1;
     */
    inline void decrementMark() {
      if (0 < mark) 
	mark--;
    };

    /** \brief
     * Sets Element's \ref mark
     */
    inline void setMark(signed char m) {
      mark = m;
    };

    /** \} */

    // ===== pure virtual methods =================================================

    /** \name pure virtual methods 
     * \{ 
     */

    /** \brief
     * orient the vertices of edges/faces.
     * Used by Estimator for the jumps => same quadrature nodes from both sides!
     */
    virtual const FixVec<int,WORLD>& 
      sortFaceIndices(int face, FixVec<int,WORLD> *vec) const = 0;

    /** \brief
     * Returns a copy of itself. Needed by Mesh to create Elements by a
     * prototype. 
     */ 
    virtual Element *clone() = 0;

    /** \brief
     * Returns which side of child[childnr] corresponds to side sidenr of 
     * this Element. If the child has no corresponding
     * side, the return value is negative. *isBisected is true after the
     * function call, if the side of the child is only a part of element's 
     * side, false otherwise. 
     */
    virtual int getSideOfChild(int childnr, int sidenr, int elType = 0) const = 0;

    /** \brief
     * Returns which vertex of elements parent corresponds to the vertexnr of
     * the element, if the element is the childnr-th child of the parent.
     * If the vertex is the ner vertex at the refinement edge, -1 is returned.
     */
    virtual int getVertexOfParent(int childnr, int vertexnr, int elType = 0) const = 0;

    /** \brief
     * Returns whether Element is a Line
     */
    virtual bool isLine() const = 0;

    /** \brief
     * Returns whether Element is a Triangle
     */
    virtual bool isTriangle() const = 0;

    /** \brief
     * Returns whether Element is a Tetrahedron
     */
    virtual bool isTetrahedron() const = 0;

    /** \brief
     * Returns whether Element has sideElem as one of its sides.
     */
    virtual bool hasSide(Element *sideElem) const = 0;

    /** \} */

    // ===== other public methods =================================================

    /** \brief
     * assignment operator
     */
    Element& operator=(const Element& old);

    /** \brief
     * Checks whether the face with vertices dof[0],..,dof[DIM-1] is
     * part of mel's boundary. returns the opposite vertex if true, -1 else
     */
    int oppVertex(FixVec<DegreeOfFreedom*, DIMEN> pdof) const;

    /** \brief
     * Refines Element's leaf data
     */
    inline void refineElementData(Element* child1, Element* child2, int elType = 0) {
      if (elementData) {
	bool remove = elementData->refineElementData(this, child1, child2, elType);
	if (remove) {
	  ElementData *tmp = elementData->getDecorated();
	  DELETE elementData;
	  elementData = tmp;
	}
      }
    };

    /** \brief
     * Coarsens Element's leaf data
     */
    inline void coarsenElementData(Element* child1, Element* child2, int elType=0) {
      ElementData *childData;
      childData = child1->getElementData();
      if (childData) {
	childData->coarsenElementData(this, child1, child2, elType);
	DELETE childData;
	child1->setElementData(NULL);
      }
      childData = child2->getElementData();
      if (childData) {
	childData->coarsenElementData(this, child2, child1, elType);
	DELETE childData;
	child2->setElementData(NULL);
      }
    };

    /** \brief
     * Returns pointer to \ref elementData
     */
    inline ElementData* getElementData() const {
      return elementData;
    };

    /** \brief
     *
     */
    inline ElementData* getElementData(int typeID) const {
      if (elementData) {
	return elementData->getElementData(typeID);
      }
      return NULL;
    };

    /** \brief
     * kills \ref elementData
     */
    bool deleteElementData(int typeID) {
      FUNCNAME("Element::deleteElementData()");
      if (elementData) {
	if (elementData->isOfType(typeID)) {
	  ElementData *tmp = elementData;
	  elementData = elementData->getDecorated();
	  DELETE tmp;
	  return true;
	} else {
	  return elementData->deleteDecorated(typeID);
	}
      }
      return false;
    };

    /** \brief
     * Returns whether element is refined at side side
     * el1, el2 are the corresponding children. 
     * (not neccessarly the direct children!)
     * elementTyp is the type of this element (comes from ElInfo)
     */
    bool isRefinedAtSide(int side, Element *el1, Element *el2, 
			 unsigned char elementTyp = 255);

    /** \brief
     * Returns whether Element's \ref newCoord is set
     */
    inline bool isNewCoordSet() const { 
      return (newCoord != NULL);
    };

    /** \brief
     * Frees memory for \ref newCoord
     */
    void eraseNewCoord();

    // ===== Serializable implementation =====
  
    void serialize(::std::ostream &out);

    void deserialize(::std::istream &in);

    // ===== protected methods ====================================================
  protected:
    /** \brief
     * Sets Element's \ref dof pointer. Used by friend class Mesh.
     */
    void setDOFPtrs();
  
    /** \brief
     * Sets Element's \ref index. Used by friend class Mesh.
     */
    inline void setIndex(int i) {
      index = i;
    };

    /** \brief
     * Used by friend class Mesh while dofCompress
     */
    void newDOFFct1(const DOFAdmin*);

    /** \brief
     * Used by friend class Mesh while dofCompress
     */
    void newDOFFct2(const DOFAdmin*);

  protected:
    /** \brief
     * Pointers to the two children of interior elements of the tree. Pointers
     * to NULL for leaf elements.
     */
    Element *child[2];

    /** \brief
     * Vector of pointers to DOFs. These pointers must be available for elements
     * vertices (for the geometric description of the mesh). There my be pointers
     * for the edges, for faces and for the center of an element. They are 
     * ordered
     * the following way: The first N_VERTICES entries correspond to the DOFs at
     * the vertices of the element. The next ones are those at the edges, if 
     * present, then those at the faces, if present, and then those at the 
     * barycenter, if present.
     */
    DegreeOfFreedom  **dof;

    /** \brief
     * Unique global index of the element. these indices are not strictly ordered
     * and may be larger than the number of elements in the binary tree (the list
     * of indices may have holes after coarsening).
     */
    int index;

    /** \brief
     * Marker for refinement and coarsening. if mark is positive for a leaf
     * element, this element is refined mark times. if mark is negative for
     * a leaf element, this element is coarsened -mark times.
     */
    signed char mark;
 
    /** \brief
     * If the element has a boundary edge on a curved boundary, this is a pointer
     * to the coordinates of the new vertex that is created due to the refinement
     * of the element, otherwise it is a NULL pointer. Thus coordinate 
     * information
     * can be also produced by the traversal routines in the case of curved 
     * boundary.
     */
    WorldVector<double> *newCoord;

    /** \brief
     * Pointer to the Mesh this element belongs to
     */
    Mesh* mesh;

    /** \brief
     * Pointer to Element's leaf data
     */
    ElementData* elementData;



    friend class Mesh;
  };

}

#endif  // AMDIS_ELEMENT_H