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

/** \file DualTraverse.h */

#ifndef AMDIS_DUALTRAVERSE_H
#define AMDIS_DUALTRAVERSE_H

#include "Traverse.h"
#include "Flag.h"
#include "AMDiS_fwd.h"

namespace AMDiS {

  /// Parallel traversal of two meshes. 
  class DualTraverse
  {
  public:
    DualTraverse() 
      : fillSubElemMat(false),
	basisFcts(NULL)
    {}

    virtual ~DualTraverse() {}

    /// Start dual traversal
    bool traverseFirst(Mesh *mesh1, 
		       Mesh *mesh2, 
		       int level1, 
		       int level2, 
		       Flag flag1,
		       Flag flag2,
		       ElInfo **elInfo1,
		       ElInfo **elInfo2,
		       ElInfo **elInfoSmall,
		       ElInfo **elInfoLarge);

    /// Get next ElInfo combination
    bool traverseNext(ElInfo **elInfoNext1,
		      ElInfo **elInfoNext2,
		      ElInfo **elInfoSmall,
		      ElInfo **elInfoLarge);

    bool check(ElInfo **elInfo1,
	       ElInfo **elInfo2,
	       ElInfo **elInfoSmall,
	       ElInfo **elInfoLarge) 
    {
      prepareNextStep(elInfo1, elInfo2, elInfoSmall, elInfoLarge);
      return true;
    }
    
    virtual bool skipEl1(ElInfo *elInfo) 
    {
      return false;
    }

    virtual bool skipEl2(ElInfo *elInfo) 
    {
      return false;
    }
    
    inline void setFillSubElemMat(bool b, const BasisFunction *fcts) 
    {
      fillSubElemMat = b;
      basisFcts = fcts;
    }
      
  protected:
    /** \brief
     * Determines smaller and larger element, determines which element(s) has to 
     * be incremented in the next step 
     */
    void prepareNextStep(ElInfo **elInfo1,
			 ElInfo **elInfo2,
			 ElInfo **elInfoSmall,
			 ElInfo **elInfoLarge);

    void fillSubElInfo(ElInfo *elInfo1, 
		       ElInfo *elInfo2,
		       ElInfo *elInfoSmall,
		       ElInfo *elInfoLarge);

  protected:
    /// Stack for mesh 1
    TraverseStack stack1;

    /// Stack for mesh 2
    TraverseStack stack2;

    /** \brief
     * used to determine whether all small elements belonging to the large
     * element are traversed.
     */
    double rest;

    /// true if element 1 should be incremented (set in prepareNextStep())
    bool inc1;

    /// true if element 2 should be incremented (set in prepareNextStep())
    bool inc2;

    /// for level traverse of mesh 1
    int level1_;

    /// for level traverse of mesh 2
    int level2_;

    /// for leaf element level traverse of mesh 1
    bool callLeafElLevel1_;

    /// for leaf element level traverse of mesh 2
    bool callLeafElLevel2_;

    /** \brief
     * If true, during dual mesh traverse for the smaller element the transformation
     * matrix will be computed. This matrix defines the transformation mapping for 
     * points defined on the larger element to the coordinates of the smaller element.
     */
    bool fillSubElemMat;

    /** \brief
     * If \ref fillSubElemMat is set to true, the corresponding transformation
     * matrices are computed. These depend on the basis functions that are used.
     */
    const BasisFunction *basisFcts;
  };

}

#endif