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//
//
//
//
// class G4ITMultiNavigator
//
// Class description:
//
// Utility class for polling the navigators of several geometries to
// identify the next  boundary. 

/// \brief { Class description:
///
/// G4ITMultiNavigator is a duplicate version of G4MultiNavigator 
///
/// Utility class for polling the navigators of several geometries to
/// identify the next  boundary.
///
/// }

// History:
// - Created. John Apostolakis, November 2006
// *********************************************************************

#ifndef G4ITMULTINAVIGATOR_HH
#define G4ITMULTINAVIGATOR_HH

#include <iostream>

#include "geomdefs.hh"
#include "G4ThreeVector.hh"
#include "G4ITNavigator.hh"

#include "G4TouchableHandle.hh"

#include "G4NavigationHistory.hh"
#include "G4TrackState.hh"
#include "G4MultiNavigator.hh"

namespace G4ITMN
{
enum ELimited
{
  kDoNot,
  kUnique,
  kSharedTransport,
  kSharedOther,
  kUndefLimited
};
}
class G4ITTransportationManager;
class G4VPhysicalVolume;

class G4ITMultiNavigator;

// Global state (retained during stepping for one track
template<>
  class G4TrackState<G4ITMultiNavigator> : public G4TrackState<G4ITNavigator>
  {
  public:
    ~G4TrackState() override
    = default;

    G4TrackState()
    {
      G4ThreeVector Big3Vector(kInfinity, kInfinity, kInfinity);
      fLastLocatedPosition = Big3Vector;
      fSafetyLocation = Big3Vector;
      fPreStepLocation = Big3Vector;

      fMinSafety_PreStepPt = -1.0;
      fMinSafety_atSafLocation = -1.0;
      fMinSafety = -kInfinity;
      fTrueMinStep = fMinStep = -kInfinity;

      for (G4int num = 0; num < G4ITNavigator::fMaxNav; ++num)
      {
        fLimitTruth[num] = false;
        fLimitedStep[num] = kUndefLimited;
        fCurrentStepSize[num] = fNewSafety[num] = -1.0;
        fLocatedVolume[num] = nullptr;
      }

      fNoLimitingStep = -1; // How many geometries limited the step
      fIdNavLimiting = -1; // Id of Navigator limiting step (if only one limits)
      fWasLimitedByGeometry = false;
    }
    ;

  protected:
    friend class G4ITMultiNavigator;
    // State after a step computation
    ELimited fLimitedStep[G4ITNavigator::fMaxNav];
    G4bool fLimitTruth[G4ITNavigator::fMaxNav];
    G4double fCurrentStepSize[G4ITNavigator::fMaxNav];
    G4double fNewSafety[G4ITNavigator::fMaxNav]; // Safety for starting point
    G4int fNoLimitingStep; // How many geometries limited the step
    G4int fIdNavLimiting; // Id of Navigator limiting step (if only one limits)

    G4bool fWasLimitedByGeometry;

    // Lowest values - determine step length, and safety
    G4double fMinStep; // As reported by Navigators. Can be kInfinity
    G4double fMinSafety;
    G4double fTrueMinStep; // Corrected in case fMinStep >= proposed

    // State after calling 'locate'
    G4VPhysicalVolume* fLocatedVolume[G4ITNavigator::fMaxNav];
    G4ThreeVector fLastLocatedPosition;

    // cache of safety information
    G4ThreeVector fSafetyLocation; //  point where ComputeSafety is called
    G4double fMinSafety_atSafLocation; // /\ corresponding value of safety
    G4ThreeVector fPreStepLocation; //  point where last ComputeStep called
    G4double fMinSafety_PreStepPt; //   /\ corresponding value of safety
  };

class G4ITMultiNavigator : public G4ITNavigator,
                           public G4TrackStateDependent<G4ITMultiNavigator>
{
public:
  // with description

  friend std::ostream& operator <<(std::ostream &os, const G4ITNavigator &n);

  G4ITMultiNavigator();
  // Constructor - initialisers and setup.

  ~G4ITMultiNavigator() override;
  // Destructor. No actions.

  G4double ComputeStep(const G4ThreeVector &pGlobalPoint,
                       const G4ThreeVector &pDirection,
                       const G4double pCurrentProposedStepLength,
                       G4double &pNewSafety) override;
  // Return the distance to the next boundary of any geometry

  G4double ObtainFinalStep(G4int navigatorId, G4double &pNewSafety, // for this geom
                           G4double &minStepLast,
                           ELimited &limitedStep);
  // Get values for a single geometry

  void PrepareNavigators();
  // Find which geometries are registered for this particles, and keep info
  void PrepareNewTrack(const G4ThreeVector position,
                       const G4ThreeVector direction);
  // Prepare Navigators and locate

  G4VPhysicalVolume* ResetHierarchyAndLocate(const G4ThreeVector &point,
                                             const G4ThreeVector &direction,
                                             const G4TouchableHistory &h) override;
  // Reset the geometrical hierarchy for all geometries.
  // Use the touchable history for the first (mass) geometry.
  // Return the volume in the first (mass) geometry.
  //
  // Important Note: In order to call this the geometries MUST be closed.

  G4VPhysicalVolume* LocateGlobalPointAndSetup(const G4ThreeVector& point,
                                               const G4ThreeVector* direction =
                                                   nullptr,
                                               const G4bool pRelativeSearch =
                                                   true,
                                               const G4bool ignoreDirection =
                                                   true) override;
  // Locate in all geometries.
  // Return the volume in the first (mass) geometry
  //  Maintain vector of other volumes,  to be returned separately
  //
  // Important Note: In order to call this the geometry MUST be closed.

  void LocateGlobalPointWithinVolume(const G4ThreeVector& position) override;
  // Relocate in all geometries for point that has not changed volume
  // (ie is within safety  in all geometries or is distance less that
  // along the direction of a computed step.

  G4double ComputeSafety(const G4ThreeVector &globalpoint,
                         const G4double pProposedMaxLength = DBL_MAX,
                         const G4bool keepState = false) override;
                         // Calculate the isotropic distance to the nearest boundary
                         // in any geometry from the specified point in the global coordinate
                         // system. The geometry must be closed.

  G4TouchableHandle CreateTouchableHistoryHandle() const override;
  // Returns a reference counted handle to a touchable history.

  G4ThreeVector GetLocalExitNormal(G4bool* obtained) override;// const
  G4ThreeVector GetLocalExitNormalAndCheck(const G4ThreeVector &CurrentE_Point,
  G4bool* obtained) override;// const
  G4ThreeVector GetGlobalExitNormal(const G4ThreeVector &CurrentE_Point,
  G4bool* obtained) override;// const
  // Return Exit Surface Normal and validity too.
  // Can only be called if the Navigator's last Step either
  //  - has just crossed a volume geometrical boundary and relocated, or
  //  - has arrived at a boundary in a ComputeStep
  // It returns the Normal to the surface pointing out of the volume that
  //   was left behind and/or into the volume that was entered.
  // Convention:x
  //   The *local* normal is in the coordinate system of the *final* volume.
  // Restriction:
  //   Normals are not available for replica volumes (returns obtained= false)

public:// without description

 G4ITNavigator* GetNavigator(G4int n) const
 {
   if( (n>fNoActiveNavigators)||(n<0))
   { n=0;}
   return fpNavigator[n];
 }

protected: // with description

  void ResetState() override;
  // Utility method to reset the navigator state machine.

  void SetupHierarchy() override;
  // Renavigate & reset hierarchy described by current history
  // o Reset volumes
  // o Recompute transforms and/or solids of replicated/parameterised
  //   volumes.

  void WhichLimited();// Flag which processes limited the step
  void PrintLimited();// Auxiliary, debugging printing
  void CheckMassWorld();

private:

  G4int fNoActiveNavigators;
  G4VPhysicalVolume* fLastMassWorld{nullptr};

  G4ITNavigator* fpNavigator[fMaxNav];// G4ITNavigator** fpNavigator;

  G4ITTransportationManager* pTransportManager;// Cache for frequent use
};

#endif