#include "cctk.h"
#include "cctk_Arguments.h"
#include "cctk_Functions.h"
#include "cctk_Parameters.h"

/***
 * This is a utility function which reads values of shiftout parameters from 
 * thorn CoordBase into an integer array offset[]. It is declared at the thorn
 * interface as GetFDGridOffsets and can be called from Fortran routines.
 * This is necessary since CCTK_ParameterGet is not available in Fortran.
 */
void get_grid_offsets (CCTK_INT *offset) {

  DECLARE_CCTK_PARAMETERS;

  int i, type;

  const CCTK_INT* shiftout_x_lower = (const CCTK_INT*) CCTK_ParameterGet ( "boundary_shiftout_x_lower", "coordbase", &type );
  if (shiftout_x_lower != NULL ) {
    offset[0] = *shiftout_x_lower;
  }
  const CCTK_INT* shiftout_x_upper = (const CCTK_INT*) CCTK_ParameterGet ( "boundary_shiftout_x_upper", "coordbase", &type );
  if (shiftout_x_upper != NULL ) {
    offset[1] = *shiftout_x_upper;
  }
  const CCTK_INT* shiftout_y_lower = (const CCTK_INT*) CCTK_ParameterGet ( "boundary_shiftout_y_lower", "coordbase", &type );
  if (shiftout_y_lower != NULL ) {
    offset[2] = *shiftout_y_lower;
  }
  const CCTK_INT* shiftout_y_upper = (const CCTK_INT*) CCTK_ParameterGet ( "boundary_shiftout_y_upper", "coordbase", &type );
  if (shiftout_y_upper != NULL ) {
    offset[3] = *shiftout_y_upper;
  }
  const CCTK_INT* shiftout_z_lower = (const CCTK_INT*) CCTK_ParameterGet ( "boundary_shiftout_z_lower", "coordbase", &type );
  if (shiftout_z_lower != NULL ) {
    offset[4] = *shiftout_z_lower;
  }
  const CCTK_INT* shiftout_z_upper = (const CCTK_INT*) CCTK_ParameterGet ( "boundary_shiftout_z_upper", "coordbase", &type );
  if (shiftout_z_upper != NULL ) {
    offset[5] = *shiftout_z_upper;
  }

}

/***
 * This function returns the effective values of local index ranges,
 * taking into account ghost zones and boundary_shiftout_* values.
 * If the use_shiftout=no, boundary offsets are set to zero.
 * Index ranges are set in Fortran convention (starting from 1):
 *  - imin <= i <= imax
 *  - jmin <= j <= jmax
 *  - kmin <= k <= kmax
 * This function is declared in interface.ccl as GetLSHIndexRanges 
 * to be used by other thorns, which need to know the actual index 
 * ranges for the region where SBP thorn will apply derivative /
 * dissipation operators.
 */
void get_lsh_iranges ( const CCTK_POINTER_TO_CONST cctkGH_, 
                 CCTK_INT *imin, CCTK_INT *imax,
                 CCTK_INT *jmin, CCTK_INT *jmax,
                 CCTK_INT *kmin, CCTK_INT *kmax)  
{
    cGH const * restrict const cctkGH = cctkGH_;
    DECLARE_CCTK_PARAMETERS
    DECLARE_CCTK_ARGUMENTS

    int i, offset[6];

    for (i=0;i<6;i++) offset[i] = 0;
    if (use_shiftout) get_grid_offsets (offset);

    *imin = 1 + ((cctk_bbox[0]) ? offset[0] : cctk_nghostzones[0]);
    *jmin = 1 + ((cctk_bbox[2]) ? offset[2] : cctk_nghostzones[1]);
    *kmin = 1 + ((cctk_bbox[4]) ? offset[4] : cctk_nghostzones[2]);

    *imax = cctk_lsh[0] - ((cctk_bbox[1]) ? offset[1] : cctk_nghostzones[0] );
    *jmax = cctk_lsh[1] - ((cctk_bbox[3]) ? offset[3] : cctk_nghostzones[1] );
    *kmax = cctk_lsh[2] - ((cctk_bbox[5]) ? offset[5] : cctk_nghostzones[2] );

}