#ifndef INC_MODELS_ALTITUDE_
#define INC_MODELS_ALTITUDE_

#include <sta/math/probability/randomVariable.hpp>

namespace sta
{
namespace models {
		class BarometricFormula
		{
            /**
             * @brief Get the altitude from the pressure using the barometric formula. The model is valid for altitudes up to leat 9 km.
             *
             * @param p Pressure in hPa
             * @return Altitude in meters
             */
		public:
            /*
            * @brief Constructor for the Barometric Formula
            * @param pRef Reference pressure in hPa
            * @param hRef Reference altitude in meters
            */
			BarometricFormula(float pRef = 1013.25, float hRef = 0);

            /* 
            * @brief Get the altitude from the pressure using the barometric formula
            * @param p Pressure in hPa
            * @return Altitude in meters
            */
            float getAltitude(float p);

		private:
			float p0_;
		};

        namespace USSA1976
        {
            /**
             * @brief Get the altitude from the pressure using the U.S. Standard Atmosphere 1976 model (https://ntrs.nasa.gov/search.jsp?R=19770009539)
             * and the barometric formula for multiple layers. The model is valid for altitudes up to at leat 71 km. See https://en.wikipedia.org/wiki/Barometric_formula for more information.
             *
             * @param p Pressure in hPa
             * @return Altitude in meters
             */
            float getAltitude(float p);
            /**
             * @brief Get the altitude as Gaussian Random Variable from the pressure as Gaussian Random Variable using the U.S. Standard Atmosphere 1976 model (https://ntrs.nasa.gov/search.jsp?R=19770009539)
             * and the barometric formula for multiple layers. The model is valid for altitudes up to at leat 71 km. See https://en.wikipedia.org/wiki/Barometric_formula for more information.
             *
             * @param p Pressure in hPa as a Gaussian Random Variable
             * @return Altitude in meters as a Gaussian Random Variable
             */
            sta::math::probability::grv getAltitude(sta::math::probability::grv p);
        }  // namespace USSA1976
}  // namespace models
}  // namespace sta

#endif //INC_MODELS_ALTITUDE_