#include "az_utils.h"
#include <math.h>

AzUtils::AzUtils() {}

#define EARTH_RADIUS 6371.0 // Earth radius in kilometers

double degrees_to_radians(double degrees)
{
    return degrees * M_PI / 180.0;
}

double AzUtils::distance(double lat1, double lon1, double lat2, double lon2)
{
    double dlat = degrees_to_radians(lat2 - lat1);
    double dlon = degrees_to_radians(lon2 - lon1);
    double a    = sin(dlat / 2) * sin(dlat / 2)
               + cos(degrees_to_radians(lat1)) * cos(degrees_to_radians(lat2)) * sin(dlon / 2) * sin(dlon / 2);
    double c = 2 * atan2(sqrt(a), sqrt(1 - a));
    return EARTH_RADIUS * c;
}