// ============================================================================
// ==                                                                        ==
// == 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 Triangle.h */

#ifndef AMDIS_TRIANGLE_H
#define AMDIS_TRIANGLE_H

#include "Element.h"

namespace AMDiS {

  /** \ingroup Triangulation 
   * \brief
   * A Triangle is a 2-dimensional Element.
   *
   * A Triangle and its refinements:
   *
   * <img src = "triangle.png">
   */
  class Triangle : public Element
  {
  public:
    /// calls base class contructor.
    Triangle(Mesh* aMesh) 
      : Element(aMesh) 
    {}

    ~Triangle() {}

    /// implements Element::clone
    inline Element *clone() 
    { 
      return new Triangle(mesh); 
    }

    /// implements Element::getVertexOfEdge
    inline int getVertexOfEdge(int i, int j) const 
    {
      return vertexOfEdge[i][j];
    }

    /// implements Element::getVertexOfPosition
    int getVertexOfPosition(GeoIndex position,
			    int positionIndex,
			    int vertexIndex) const;

    /// implements Element::getGeo
    inline int getGeo(GeoIndex i) const 
    {
      switch (i) {
      case VERTEX: case PARTS: case NEIGH:
	return 3;
	break;
      case EDGE:
	return 3;
      case FACE:
	return 0;
      case CENTER:
	return 1;
	break;
      case DIMEN:
	return 2;
	break;
      case BOUNDARY:
	return 6;
	break;
      case PROJECTION:
	return 3;
	break;
      default:
	ERROR_EXIT("invalid geo-index\n");
	return 0;
      }
    }

    /// implements Element::hasSide
    bool hasSide(Element* sideElem) const;

    /// implements Element::sortFaceIndices
    const FixVec<int,WORLD>& sortFaceIndices(int face, FixVec<int,WORLD> *vec) const;

    /// implements Element::isLine. Returns false because this element is a Triangle
    inline bool isLine() const 
    { 
      return false; 
    }
 
    /// implements Element::isTriangle. Returns true because this element is a Triangle
    inline bool isTriangle() const 
    { 
      return true; 
    }

    /// implements Element::isTetrahedron. Returns false because this element is a Triangle
    inline bool isTetrahedron() const 
    { 
      return false; 
    }

    /// Element type number is not used in 2d, so return 0.
    inline int getChildType(int) const
    {
      return 0;
    }

    /// implements Element::getSideOfChild()
    virtual int getSideOfChild(int child, int side, int) const 
    {
      FUNCNAME("Triangle::getSideOfChild()");
      TEST_EXIT_DBG(child==0 || child==1)("child must be in (0,1)\n");
      TEST_EXIT_DBG(side >= 0 && side <= 2)("side must be between 0 and 2\n");
      return sideOfChild[child][side];
    }

    /// implements Element::getVertexOfParent()
    virtual int getVertexOfParent(int child, int side, int = 0) const 
    {
      FUNCNAME("Triangle::getVertexOfParent()");
      TEST_EXIT_DBG(child==0 || child==1)("child must be in (0,1)\n");
      TEST_EXIT_DBG(side >= 0 && side <= 2)("side must be between 0 and 2\n");
      return vertexOfParent[child][side];
    }

    virtual int getPositionOfVertex(int side, int vertex) const 
    {
      static int positionOfVertex[3][3] = {{-1, 0, 1}, {1, -1, 0}, {0, 1, -1}};
      return positionOfVertex[side][vertex];
    }

    inline int getEdgeOfFace(int face, int edge) const 
    {
      TEST_EXIT_DBG(face == 0)("face must be zero at triangle\n");
      TEST_EXIT_DBG(edge >= 0 && edge < 3)("invalid edge\n");
      return edge;
    }
 
    std::string getTypeName() const 
    { 
      return "Triangle"; 
    }

    void getVertexDofs(FiniteElemSpace* feSpace, 
		       BoundaryObject bound,
		       DofContainer& dofs, 
		       bool parentVertices = false) const;

    void getNonVertexDofs(FiniteElemSpace* feSpace, 
			  BoundaryObject bound,
			  DofContainer& dofs) const;

  protected:
    /** \brief
     * vertexOfEdge[i][j] is the local number of the j-th vertex of the i-th 
     * edge of this element.
     */
    static const int vertexOfEdge[3][2];

    static const int sideOfChild[2][3];

    static const int vertexOfParent[2][3];
  };

}

#endif // AMDIS_TRIANGLE_H