///////////////////////////////////////////////////////////////////////
//
// Calculates the Reconstructed Energy from a general Functional Form
//
// Author: Krish Majumdar <Krishanu.Majumdar@physics.ox.ac.uk> -- contact person
//
// REVISION HISTORY:
//     - 20/06/2014 : Krish Majumdar - new file
//     - 04/09/2014 : Krish Majumdar - changes to variable names to make
//                    things more specific
//     - 28/11/2014 : Matt Strait - Doxygen fixes
//     - 11/01/2015 : Krish Majumdar - added external event reconstruction
//     - 06/05/2015 : Matt Mottram - added ability to run in partial fill
//     - 04/06/2015 : Krish Majumdar - code review changes
//
// The general function is: H = f(E) * f(r) * f(z), where:
//   H is a "segmentor parameter",
//   f(E) is a function of energy,
//   f(r) is a function of radius, the exact form of which is radius-dependent,
//   f(z) is a function of z.
//   This general function is inverted to give the energy.
//
// See DocDB-2782 for more information on this fitter.
//
///////////////////////////////////////////////////////////////////////

#ifndef __RAT_Method_EnergyFunctional__
#define __RAT_Method_EnergyFunctional__

#include <string>
#include <vector>
#include <RAT/DS/FitResult.hh>
#include <RAT/SeededMethod.hh>

namespace RAT
{
  namespace Methods
  {
    class EnergyFunctional : public SeededMethod
    {

    public:
      // Returns the method's name
      virtual std::string GetName() const { return EnergyFunctional::Name(); }
      // Returns the method's name
      static std::string Name() { return std::string("energyFunctional"); }
      // Initialise the method
      //
      // "param" is an optional index in the db to use
      void Initialise(const std::string& param);
      // Load the table from the database
      void BeginOfRun(DS::Run& run);
      void EndOfRun(DS::Run& run);
      // Set the seed to the default
      void DefaultSeed();
      // Calculate and return the best fit for the seed
      virtual DS::FitResult GetBestFit();

    private:
      std::string fIndex; // Optional index override for the db table
      std::string fMaterial; // Material being used in the simulation ... must be a global variable to set the validity in the GetBestFit() function
      std::vector<double> fEnergyCoefficients; // f(E) parameters
      std::vector<double> fRadiusCoefficients_Internal_Low; // f(r) parameters when r in the low-radius internal region
      double fRadiusCutoff_Internal_Mid; // Radius cutoff defining the boundary between the low- and middle-radius internal regions
      std::vector<double> fRadiusCoefficients_Internal_Mid; // f(r) parameters when r in the middle-radius internal region
      double fRadiusCutoff_Internal_High; // Radius cutoff defining the boundary between the middle- and high-radius internal regions
      std::vector<double> fRadiusCoefficients_Internal_High; // f(r) parameters when r in the high-radius internal region
      double fRadiusCutoff_External_Low; // Radius cutoff defining the boundary between the high-radius internal and low-radius external regions
      std::vector<double> fRadiusCoefficients_External_Low; // f(r) parameters when r in the low-radius external region
      double fRadiusCutoff_External_High; // Radius cutoff defining the boundary between the low- and high-radius external regions
      std::vector<double> fRadiusCoefficients_External_High; // f(r) parameters when r in the high-radius external region
      std::vector<double> fZCoefficients; // f(z) parameters, covering both internal and external regions
      double fAVRadius; // AV radius, taken from geometry file

      // General function for calculating the value of a polynomial of any order
      //
      // "coefficients" is a vector of coefficients, ordered by increasing power of "parameter"
      // "parameter" is the independent variable in the polynomial
      double EvaluatePolynomial(std::vector<double> coefficients, double parameter);
    };
  } //::Method
} //::RAT

#endif