#include <Rcpp.h>

#ifdef _OPENMP

#include <omp.h>

#endif

using namespace Rcpp;

double profoundBoxFlux(NumericMatrix image, double cx, double cy, double size, int nthreads = 1) {

int nrow = image.nrow();

int ncol = image.ncol();

cx -= 0.5;

cy -= 0.5;

double half_size = size / 2;

int start_row = std::max(0.0, ceil(cx - half_size));

int end_row = std::min(nrow - 1.0, floor(cx + half_size));

int start_col = std::max(0.0, ceil(cy - half_size));

int end_col = std::min(ncol - 1.0, floor(cy + half_size));

double sum = 0.0;

#ifdef _OPENMP

// Parallelize the main loop

#pragma omp parallel for collapse(2) schedule(static) num_threads(nthreads)

#endif

for (int i = start_row; i <= end_row; ++i) {

for (int j = start_col; j <= end_col; ++j) {

if(!NumericMatrix::is_na(image(i, j))){

sum += image(i, j);

}

}

}

return sum;

}