// GetDP - Copyright (C) 1997-2018 P. Dular and C. Geuzaine, University of Liege
//
// See the LICENSE.txt file for license information. Please report all
// issues on https://gitlab.onelab.info/getdp/getdp/issues

#include <string.h>
#include <math.h>
#include "ProData.h"
#include "GeoData.h"
#include "MallocUtils.h"
#include "Message.h"

#define SQU(a)     ((a)*(a)) 

extern struct Problem    Problem_S ;
extern struct GeoData  * CurrentGeoData ;

int  fcmp_NXE(const void * a, const void * b)
{
  return 
    ((struct Entity2XEntity1 *)a)->Num -
    ((struct Entity2XEntity1 *)b)->Num ;
}

int  fcmp_EXVector(const void * a, const void * b)
{
  return 
    ((struct EntityXVector *)a)->Num -
    ((struct EntityXVector *)b)->Num ;
}

/*
  C'est une maniere un peu naive de creer cette BD. Mais elle a 
  l'avantage de permettre une allocation simple (et minimum).

  L'autre possibilite (boucler sur les elemnts) est plus rapide, mais
  je ne vois pas bien comment obtenir un cout memoire minimum simplement, 
  sans faire de nombreux realloc.
*/

#define MAX_NBR_NXE_INCIDENCE 20 

static int RegionIndexForNXE = -1;

void Geo_CreateNodesXElements(int NumNode, int InIndex, 
			      int *NbrElements, int **NumElements)
{
  struct Entity2XEntity1   NXE, *NXE_P ;
  struct Geo_Element      *GeoElement ;
  struct Group            *Group_P ;

  int    i, j, tmp[MAX_NBR_NXE_INCIDENCE] ;

  Group_P = (struct Group*)List_Pointer(Problem_S.Group, InIndex);

  if(InIndex != RegionIndexForNXE){
    RegionIndexForNXE = InIndex ;
    Message::Info("  Generate NodesXElements information for Region '%s'", Group_P->Name);
    if(CurrentGeoData->NodesXElements)
      Tree_Delete(CurrentGeoData->NodesXElements);
    CurrentGeoData->NodesXElements = 
      Tree_Create(sizeof(struct Entity2XEntity1), fcmp_NXE) ;
  }
  
  NXE.Num = NumNode ;
  
  if((NXE_P = (struct Entity2XEntity1*)
      Tree_PQuery(CurrentGeoData->NodesXElements, &NXE))) {
    *NbrElements = NXE_P->NbrEntities ;
    *NumElements = NXE_P->NumEntities ;
  }
  else{
    NXE.NbrEntities = 0 ;
    for (i = 0 ; i < Geo_GetNbrGeoElements(); i++) {
      GeoElement = Geo_GetGeoElement(i) ;
      if (List_Search(Group_P->InitialList, &GeoElement->Region, fcmp_int)){
	for(j=0 ; j<GeoElement->NbrNodes ; j++){
	  if(GeoElement->NumNodes[j] == NumNode){

	    /* printf("Adding elm %d to node %d\n", GeoElement->Num, NumNode); */
	    /* this is to have orientation of elements adjacent to the node 
	       Only valid for line elemnts !!!!!!! */
	    
	    tmp[NXE.NbrEntities] = ((!j)?-1:1) * GeoElement->Num ;
	    NXE.NbrEntities++ ;
	  }
	}
      }
    }
    NXE.NumEntities = (int*)Malloc(NXE.NbrEntities * sizeof(int)) ;
    memcpy(NXE.NumEntities, tmp, NXE.NbrEntities * sizeof(int));
    Tree_Add(CurrentGeoData->NodesXElements, &NXE);
    *NbrElements = NXE.NbrEntities ;
    *NumElements = NXE.NumEntities ;
  }
}

void Geo_CreateNormal(int Type, double *x, double *y, double *z, double *N)
{
  double  x1x0, x2x0, y1y0, y2y0, z1z0, z2z0 ;
  double  nx, ny, nz, norm ;

  switch (Type) {

  case LINE :
  case LINE_2 :
    nx = y[1] - y[0] ;
    ny = x[0] - x[1] ;
    norm = sqrt(SQU(nx)+SQU(ny)) ;      
    N[0] = nx / norm ;
    N[1] = ny / norm ;
    N[2] = 0. ;
    break ;

  case TRIANGLE :
  case TRIANGLE_2 :
  case QUADRANGLE :
  case QUADRANGLE_2 :
    x1x0 = x[1] - x[0] ;
    y1y0 = y[1] - y[0] ;
    z1z0 = z[1] - z[0] ;
    x2x0 = x[2] - x[0] ; 
    y2y0 = y[2] - y[0] ;
    z2z0 = z[2] - z[0] ;
    nx = y1y0 * z2z0 - z1z0 * y2y0 ;
    ny = z1z0 * x2x0 - x1x0 * z2z0 ;
    nz = x1x0 * y2y0 - y1y0 * x2x0 ;
    norm = sqrt(SQU(nx)+SQU(ny)+SQU(nz)) ;
    N[0] = nx/norm ;
    N[1] = ny/norm ;
    N[2] = nz/norm ;
    break ;
    
  default :
    Message::Error("Normal computation not done (yet) for Element Type %d", Type);
  }
}

void Geo_CreateNormalOfElement(struct Geo_Element *GeoElement, double *Normal)
{
  struct  EntityXVector  EXV, *EXV_P ;
  double  x [NBR_MAX_NODES_IN_ELEMENT] ;
  double  y [NBR_MAX_NODES_IN_ELEMENT] ;
  double  z [NBR_MAX_NODES_IN_ELEMENT] ;

  EXV.Num = GeoElement->Num ;

  if((EXV_P = (struct EntityXVector*)Tree_PQuery(CurrentGeoData->Normals, &EXV))) {
    memcpy(Normal, EXV_P->Vector, 3*sizeof(double));
  }
  else{
    Geo_GetNodesCoordinates(GeoElement->NbrNodes, GeoElement->NumNodes, x, y, z) ;
    Geo_CreateNormal(GeoElement->Type, x, y, z, Normal);
    memcpy(EXV.Vector, Normal, 3*sizeof(double));
    Tree_Add(CurrentGeoData->Normals, &EXV);    
  }
}
