////////////////////////////////////////////////////////////////////////
/// \class  RAT::Segmentor
///
/// \brief  Class assigns each PMT to an equal solid angle detector segment
///         labelled by an int. Returns these SegmentIDs and the
///         populations of each Segment.
///
///
/// \author Jack Dunger <jack.dunger@physics.ox.ac.uk>
///
/// REVISION HISTORY:
///-         2014-04-4  : J.Dunger - New file.
///-         2014-04-11 : P Jones  - Moved to DU.
///-         2014-10-14 : J.Dunger - Added HWStatus check
///-         2015-02-15 : J.Dunger - Add arbitary orientations of segments
///-         2015-05-20 : J.Dunger - Add arbitary pattern origin
///
/// \details Divides detector into ndiv divisions in both theta, phi
///         to give ndiv * ndiv approximately equal solid angle segments.
///         Returns a vector of ints, one entry for each PMT, the
///         values indicating which segment each PMT belongs to (IDs).
///         The first segment begins at theta=phi=0, the labels then
///         increase by one moving around phi and by ndiv moving around
///         theta. The SetPatternZaxis sets where the 'north pole' of the
///         pattern is, the x,y axes are calculated automatically.
///
///
////////////////////////////////////////////////////////////////////////

#ifndef __RAT_Segmentor__
#define __RAT_Segmentor__

#include <TObject.h>
#include <TVector3.h>

#include <vector>

namespace RAT
{

namespace DU
{

class Segmentor : public TObject
{
public:
  /// Default to 10 divisions, pattern centered at detector north
  Segmentor(): fNDivisions(10), fPatternZaxis(TVector3(0,0,1)), fPatternXaxis((TVector3(1,0,0))),
               fPatternYaxis(TVector3(0,1,0)), fPatternOrigin(TVector3(0,0,0)) {}

  /// Recalculates segments on new runs
  void BeginOfRun() { Calculate(); }

  /// Set the number of divisions, recalculates the segment IDs and populations
  ///
  /// @param[in] numberOfDivisions
  void SetNumberOfDivisions( const unsigned int numberOfDivisions ) {
      fNDivisions = numberOfDivisions;
      Calculate();
  }

  /// Get the number of divisions
  ///
  /// @return number of divisions
  unsigned int GetNumberOfDivisions() const { return fNDivisions; }

  ///  Set the z-axis of the segmentation pattern
  ///
  ///  param[in] patternZaxis vector in direction of new pattern z-axis
  void SetPatternZaxis (const TVector3& patternZaxis);

  /// Set the z-axis of the segmentation pattern and the number of segments
  ///
  /// @param[in] numberOfDivisions The new number of divisions
  /// @param[in] patternZaxis vector in direction of new pattern z-axis
  void SetPatternZaxis (const TVector3& patternZaxis, const int numberOfDivisions);

  /// Set the origin, z-axis of the segmentation pattern
  ///
  /// @param[in] numberOfDivisions The new number of divisions
  /// @param[in] patternOrigin The new pattern origin
  /// @param[in] patternZaxis The pattern axis relative to the new origin
  void SetPatternOrigin(const TVector3& patternOrigin, const TVector3& patternZaxis,
                        const int numberOfDivisions);

  ///Get origin of the segmentation pattern
  ///
  /// @returns the pattern origin
  TVector3 GetPatternOrigin() const {return fPatternOrigin;}

  ///Get the z-axis of the segmentation pattern
  ///
  /// @returns the z-axis of the co-ordinate pattern
  TVector3 GetPatternZaxis() const {return fPatternZaxis;}

  /// Get the x-axis of the segmentation pattern
  ///
  /// @returns the x-axis of the co-ordinate pattern
  TVector3 GetPatternXaxis() const {return fPatternXaxis;}

  /// Get the y-axis of the segmentation pattern
  ///
  /// @returns the y-axis of the co-ordinate pattern
  TVector3 GetPatternYaxis() const {return fPatternYaxis;}

  /// Get the Segment IDs
  ///
  /// @return vector of segment IDs by PMT ID
  std::vector<unsigned int> GetSegmentIDs()  const { return fSegmentIDs; }

  /// Get the online population per segment
  ///
  /// @return vector of populations by segment ID
  std::vector<unsigned int> GetSegmentPopulations() const { return fPopulations; }

  // This ROOT macro adds dictionary methods to this class.
  // The number is 0 as this class is never, and should never be written to disc.
  // It assumes this class has no virtual methods, use ClassDef if change this.
  ClassDefNV( Segmentor, 0 );
private:
  /// Calculate the Segment IDs and proportions given the current PMTInfo
  void Calculate();

  std::vector<unsigned int> fSegmentIDs; ///< Segment ID by PMT ID (LCN)
  std::vector<unsigned int> fPopulations; ///< Count of online (tube and channel) PMTs in each segment

  unsigned int fNDivisions; ///< The number of divisions to use

  TVector3 fPatternZaxis; ///< Unit z-axis of the pattern
  TVector3 fPatternXaxis; ///< Unit x-axis of the pattern
  TVector3 fPatternYaxis; ///< Unit y-axis of the pattern
  TVector3 fPatternOrigin; ///< Pattern origin in SNO+ co-ordinates

};

} //::DU

} //Namespace RAT

#endif   //__RAT_Segmentor__