GeoCoord.h

#pragma once

#include <algorithm>
#include <string>
#include <cstring>
#include <cstdint>
#include <math.h>
#include <stdint.h>
#include <stdexcept>
#include <memory>

#define PI 3.1415926535897932384626433832795
#define OLC_CODE_LEN 11

// Helper functions
// Raises a number to an exponent, handling negative exponents.
static inline double pow_neg(double base, double exponent) {
  if (exponent == 0) {
    return 1;
  } else if (exponent > 0) {
    return pow(base, exponent);
  }
  return 1 / pow(base, -exponent);
}

static inline double toRadians(double deg)
{
    return deg * PI / 180;
}

static inline double toDegrees(double r)
{
    return r * 180 / PI;
}

// GeoCoord structs/classes
// A struct to hold the data for a DMS coordinate.
struct DMS
{
    uint8_t latDeg;
    uint8_t latMin;
    uint32_t latSec;
    char latCP;
    uint8_t lonDeg;
    uint8_t lonMin;
    uint32_t lonSec;
    char lonCP;
};

// A struct to hold the data for a UTM coordinate, this is also used when creating an MGRS coordinate.
struct UTM 
{
    uint8_t zone;
    char band;
    uint32_t easting;
    uint32_t northing;
};

// A struct to hold the data for a MGRS coordinate.
struct MGRS
{
    uint8_t zone;
    char band;
    char east100k;
    char north100k;
    uint32_t easting;
    uint32_t northing;
};

// A struct to hold the data for a OSGR coordiante
struct OSGR {
    char e100k;
    char n100k;
    uint32_t easting;
    uint32_t northing;
};

// A struct to hold the data for a OLC coordinate
struct OLC {
    char code[OLC_CODE_LEN + 1]; // +1 for null termination
};

class GeoCoord {
    private:
        int32_t _latitude = 0;
        int32_t _longitude = 0;
        int32_t _altitude = 0;

        DMS _dms;
        UTM _utm;
        MGRS _mgrs;
        OSGR _osgr;
        OLC _olc;

        bool _dirty = true;

        void setCoords();

    public:
        GeoCoord();
        GeoCoord(int32_t lat, int32_t lon, int32_t alt);
        GeoCoord(double lat, double lon, int32_t alt);
        GeoCoord(float lat, float lon, int32_t alt);

        void updateCoords(const int32_t lat, const int32_t lon, const int32_t alt);
        void updateCoords(const double lat, const double lon, const int32_t alt);
        void updateCoords(const float lat, const float lon, const int32_t alt);

        // Conversions
        static void latLongToDMS(const double lat, const double lon, DMS &dms);
        static void latLongToUTM(const double lat, const double lon, UTM &utm);
        static void latLongToMGRS(const double lat, const double lon, MGRS &mgrs);
        static void latLongToOSGR(const double lat, const double lon, OSGR &osgr);
        static void latLongToOLC(const double lat, const double lon, OLC &olc);
        static void convertWGS84ToOSGB36(const double lat, const double lon, double &osgb_Latitude, double &osgb_Longitude);
        static float latLongToMeter(double lat_a, double lng_a, double lat_b, double lng_b);
        static float bearing(double lat1, double lon1, double lat2, double lon2);
        static float rangeRadiansToMeters(double range_radians);
        static float rangeMetersToRadians(double range_meters);

        // Point to point conversions
        int32_t distanceTo(GeoCoord pointB);
        int32_t bearingTo(GeoCoord pointB);
        std::shared_ptr<GeoCoord> pointAtDistance(double bearing, double range);

        // Lat lon alt getters
        int32_t getLatitude() const { return _latitude; }
        int32_t getLongitude() const { return _longitude; }
        int32_t getAltitude() const { return _altitude; }

        // DMS getters
        uint8_t getDMSLatDeg() const { return _dms.latDeg; }
        uint8_t getDMSLatMin() const { return _dms.latMin; }
        uint32_t getDMSLatSec() const { return _dms.latSec; }
        char getDMSLatCP() const { return _dms.latCP; }
        uint8_t getDMSLonDeg() const { return _dms.lonDeg; }
        uint8_t getDMSLonMin() const { return _dms.lonMin; }
        uint32_t getDMSLonSec() const { return _dms.lonSec; }
        char getDMSLonCP() const { return _dms.lonCP; }

        // UTM getters
        uint8_t getUTMZone() const { return _utm.zone; }
        char getUTMBand() const { return _utm.band; }
        uint32_t getUTMEasting() const { return _utm.easting; }
        uint32_t getUTMNorthing() const { return _utm.northing; }

        // MGRS getters
        uint8_t getMGRSZone() const { return _mgrs.zone; }
        char getMGRSBand() const { return _mgrs.band; }
        char getMGRSEast100k() const { return _mgrs.east100k; }
        char getMGRSNorth100k() const { return _mgrs.north100k; }
        uint32_t getMGRSEasting() const { return _mgrs.easting; }
        uint32_t getMGRSNorthing() const { return _mgrs.northing; }

        // OSGR getters
        char getOSGRE100k() const { return _osgr.e100k; }
        char getOSGRN100k() const { return _osgr.n100k; }
        uint32_t getOSGREasting() const { return _osgr.easting; }
        uint32_t getOSGRNorthing() const { return _osgr.northing; }

        // OLC getter
        void getOLCCode(char* code) { strncpy(code, _olc.code, OLC_CODE_LEN + 1); } // +1 for null termination
};