#include "solid_angle.h"
#include <math.h>
#include <stdio.h>

int isclose(double a, double b, double rel_tol, double abs_tol)
{
    /* Returns 1 if a and b are "close". This algorithm is taken from Python's
     * math.isclose() function.
     *
     * See https://www.python.org/dev/peps/pep-0485/. */
    return fabs(a-b) <= fmax(rel_tol*fmax(fabs(a),fabs(b)),abs_tol);
}

int test_solid_angle(char *err)
{
    /* Tests the get_solid_angle() function. */
    double pmt[3] = {0,0,0};
    double pos[3] = {0,0,1};
    double n[3] = {0,0,1};
    double r = 1.0;
    double solid_angle;

    solid_angle = get_solid_angle(pos,pmt,n,r);

    if (!isclose(solid_angle, 2*M_PI*(1-1/sqrt(2)), 1e-9, 0)) {
        sprintf(err, "solid angle = %.2f, but expected %.2f", solid_angle, 2*M_PI*(1-1/sqrt(2)));
        return 1;
    }

    return 0;
}

int main(int argc, char **argv)
{
    char err[256];

    if (!test_solid_angle(err)) {
        printf("[\033[92mok\033[0m] test_solid_angle\n");
        return 0;
    } else {
        printf("[\033[91mfail\033[0m] test_solid_angle: %s\n", err);
        return 1;
    }
}