////////////////////////////////////////////////////////////////////
/// \class RAT::AfterPulse
///
/// \brief  Simulate after pulsing in the PMTs.
///
/// \author Tanner Kaptanoglu <tannerk@hep.upenn.edu>
///
/// REVISION HISTORY:\n
///    12 Sept 2016 : Tanner Kaptanoglu - first version
///
///  \details  Generates after pulsing created in the PMTs
///            at a user-defined probability per photoelectron.
///            Handles passing photoelectrons across events, as
///            required by late after-pulses.
///
////////////////////////////////////////////////////////////////////
#ifndef __RAT_AfterPulse_hh__
#define __RAT_AfterPulse_hh__

#include <RAT/DS/Entry.hh>
extern "C" {
#include <stdint.h>
}

namespace RAT
{

  class AfterPulse
  {
    public:
      AfterPulse();
      ~AfterPulse();

      void BeginOfRun();

      // Builds a vector containing all of the after-pulse hit times
      // in their universal times, so that later events can check
      // if an after pulse, created in a previous event, fell into
      // its trigger window.
      void GenerateAfterPulse(const int& days, const int& secs,
                              const double& nsecs);

      // Samples the after-pulsing time distribution
      double CalculateAfterPulseTime();

    protected:

      // Decides if the after-pulse was detected and, if so,
      // builds the after-pulse photoelectron
      void DetectAfterPulse(const uint64_t& event_time);

      int fAPFlag; // Flag specifing whether to run the after-pulsing
      double fAPFraction; // Fraction of photoelectrons that create an after-pulse
      std::vector<double> fAPTime; // Time distribution of the after-pulse
      std::vector<double> fAPProb; // Probability of each time

      size_t fPMTCount; // Number of PMTs
      float fTriggerWindow;

      // After-pulse time for each created after pulse
      std::vector <std::vector<uint64_t> > fAfterPulseTime;
      // Front-end time for each PE
      std::vector <std::vector<uint64_t> > fFrontEndTime;
      // Used as an index for after-pulsing vector
      std::vector<size_t> countAP;
  };

} // namespace RAT

#endif