// RandomRegistry.h

#ifndef RandomRegistry_H
#define RandomRegistry_H

// Maintains a list of pointers to RandomGenerator objects.
// The method record is called to record the state of each
// and set is called to reset the state of each to previously recorded
// values.

#include <vector>
#include <iosfwd>
#include "ptr/Ptr.h"
#include "ptr/NullPolicy.h"
#include "ptr/AutoPolicy.h"
#include "RandomGenerator.h"

class RandomRegistry {

private:  // typedefs

  // Random generator pointer.
  typedef Ptr<RandomGenerator,NullPolicy> GenPtr;

  // Const random generator pointer.
  typedef Ptr<const RandomGenerator, AutoPolicy> CGenPtr;

  // list of generators
  typedef std::vector<GenPtr> GenList;

  // const list of generators
  typedef std::vector<CGenPtr> CGenList;

  // pointer to such a list
  typedef Ptr<CGenList,AutoPolicy> CGenListPtr;

  // list of generator lists
  typedef std::vector<CGenListPtr> StateList;

private:  // attributes

  // Known generators.
  GenList _gens;

  // Array of states for each generator.
  StateList _states;

private:  // methods

  // output stream.
  void ostr(std::ostream& stream) const;

  // Hide copy.
  RandomRegistry(const RandomRegistry& rhs);

  // Hide assignment.
  RandomRegistry& operator=(const RandomRegistry& rhs);

public:  // methods

  // Constructor.
  RandomRegistry();

  // Destructor.
  ~RandomRegistry();

  // Register a generator.
  void add_generator(RandomGenerator& gen);

  // Record the states.  A unique integer labeling the state is returned.
  int record();

  // Return the number of registered generators.
  int get_generator_count() const;

  // Return the number of recorded states.
  int get_state_count() const;

  // Reset the states.
  // Return nonzero for error (e.g. unknown state index).
  int set(int istate);

  // output stream
  friend std::ostream&
  operator<<(std::ostream& stream, const RandomRegistry& reg);

};

#endif