#ifndef SIBARREL_HPP
#define SIBARREL_HPP
//
// $Id: SiBarrel.hpp,v 1.10 2001/02/03 22:53:35 hobbs Exp $
//
// File: SiBarrel.hh
// Purpose: 
// Created: 10-OCT-1997   John Hobbs
//
// $Revision: 1.10 $
//
//

// Include files
#include <list>
#include <vector>
#include <silicon_geometry/base/SiLayer.hpp>
#include <geometry_system/components/ReferencePoint.hpp>

// Global definitions

  /**
  Barrel section of the SMT.

  A SiBarrel is used to position the eight layers of silicon detector
  units (i.e. ladders) composing each of the SMT barrels.  
  */

class SiBarrel: public dgs::ReferencePoint {
public:

  /// Default constructor (empty barrel).
  SiBarrel();

  /**
          Construct a barrel containing the given layers.
          If the ladders are spun to be anti-parallel to the global $z$ 
          direction, flip them around here.
         
          @param spun If spun is false, then the (ideal) ladder local 
                      $z$ axis is parallel to global $z$. If true, local 
                      $z$ is anti-parallel to global $z$.
  */
  SiBarrel(const std::vector<SiLayer> &layers, bool spun=false);

  /** 
                 Return the address of the children.  
                 Used within dgs::GeometryElement and ReferencePoint to do 
                 positioning.
  */
  const std::list<dgs::GeometryElement*> get_children();

  // Accessors and some I/O

  /// Return the number of layers.
  int get_layer_count() const;

  /// Return a constant reference to the ilayer-th layer. 
  const SiLayer* get_layer(int ilayer)  const;

  /// Return a modifiable reference to the ilayer-th layer. 
  SiLayer* get_mutable_layer(int ilayer);

  /// Text dump a barrel.
  friend std::ostream& operator <<(std::ostream& os, const SiBarrel& me);
  friend bool operator<(const SiBarrel& lhs, const SiBarrel &rhs);

  /// Test that the barrels have the same layers (number and contents)
  friend bool operator==(const SiBarrel& lhs, const SiBarrel &rhs);
  friend bool operator!=(const SiBarrel& lhs, const SiBarrel &rhs);

private:

  /// Vector to hold the layers.
  std::vector<SiLayer> _layers;

  /// Rotate a ladder of $180^o$ around the local $y$ axis.
  void flip_ladders(); 

public:

  D0_OBJECT_SETUP(SiBarrel);

};

// Inlines
#include <silicon_geometry/base/SiBarrel.icc>
#endif //SIBARREL_HPP