/** @class RAT::VertexGen_UFO
 *
 *  @brief Vertex generator - for UFO (Modified from VertexGen_Laserball)
 *
 *  @author Mark Stringer <ms711@sussex.ac.uk>
 *
 *  REVISION HISTORY\n
 *  Mark Stringer - First Commit
 *    10-02-2017 :N. Barros : - Added BeginOfRun and moved DB loading there
 */


#ifndef __RAT_VertexGen_UFO__
#define __RAT_VertexGen_UFO__

#include <RAT/GLG4VertexGen.hh>
#include <vector>
#include <globals.hh>
#include <CLHEP/Random/RandGeneral.h>
#include "RAT/GLG4Gen.hh"
#include <G4ThreeVector.hh>

#include "TF2.h"

class G4ParticleDefinition;

namespace RAT {

    class VertexGen_UFO : public GLG4VertexGen {
        public:
            /** Class constructor. Does nothing besides it, initialization done in Init*/
            VertexGen_UFO(const char *arg_dbname="vertexufo");
            /** Class destructor. Does nothing */
            virtual ~VertexGen_UFO();
            /** Initialization, called in the first event. Reads all parameters from ratdb.*/
            void Init();
            /** Main event generation function */
            virtual void GeneratePrimaryVertex(G4Event *event,
                    G4ThreeVector &dx,
                    G4double dt);
            /** Helper function. Returns random number given input distribution and cumulative distribution*/
            float SampleRandom(std::vector<float> myx, std::vector<float> myy, std::vector<float> mycum);

            /** Do no use to avoid overriding parameters read from ratdb.*/
            virtual void SetState(G4String);
            virtual G4String GetState();
            virtual void BeginOfRun();

        private:


            //Now the parameters

            /** Only call the initialisation once - if this flag isn't set */
            bool  fInitDB;

            /** Number of photons per UFO pulse */
            int fPhotonsPerEvent;
            /** true = number of photons per pulse is selected from poisson distribution with mean=photons_per_event, \n
              false = number of photons per pulse=photons_per_event */
            bool fPoisson;

            /** Vector for specified wavelengths */
            std::vector<float> fwave;
            /** Vector for cumulative wave intensity distribution */
            std::vector<float> fwaveCumMag;
            /** Vector for wave intensity */
            std::vector<float> fwaveInt;
            /** Lower limit on wavelength distribution */
            float fMinWl;
            /** Upper limit on wavelength distribution */
            float fMaxWl;

            /**Vector for angles*/
            std::vector<float> fangle;

            /**Vector for angular distribution*/
            std::vector<float> fAngInt;

            /**Vector for cumulative angular distribution*/
            std::vector<float> fCumAngleDist;

            /** Number of LEDS on the UFO */
            int fNleds;

            /**Radius of UFO in mm */
            double fUFORadius;

            /**Time it takes the LED pulsing to pass around the entire UFO*/
            double fRotationTime;

            /**Time width of LED light pulse*/
            double fTimeWidth;

            /** Positions of UFO LEDs relative to the centre of the UFO
             * the unit vector of these will give the direction of the UFO LED*/
            std::vector<double> fUFO_XPos;
            std::vector<double> fUFO_YPos;
            std::vector<double> fUFO_ZPos;

            /**Counts the number of times the LED has flashed to ensure correct UFO LED is flashing*/
            long fLEDFlashCount;

            /**Number of flashes for entire rotation of LED*/
            long fFlashesPerRotation;

            /**Flash rate of LEDs*/
            long fFlashRate;

            /** Generate Lambertian distribution from angular array (IN RADIANS)*/
            std::vector<float> GenerateLambertian(std::vector<float>  angularDistribution);

            /**Method to generate the photons direction given the direction of the LED and the angle generated from the angular distribution*/
            G4ThreeVector GeneratePhotonDirection(G4ThreeVector led_dir, float angle);

            /**Taken from VertexGen_Laserball*/
            /** Helper function for gaussian random*/
            double GasDev();


            /** Particles must be defined as optical photons */
            G4ParticleDefinition *fPhotonDef;

    };


} // namespace RAT

#endif