// src/backend/history.hh - Copyright 2005, 2006, University
//               of Padova, dept. of Pure and Applied
//               Mathematics
//
// This file is part of SGPEMv2.
//
// This is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// SGPEMv2 is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with SGPEMv2; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#ifndef HISTORY_HH
#define HISTORY_HH 1

#include "config.h"

#include <vector>
#include <iostream>

#include "slice.hh"
#include "observed_subject.hh"
#include "schedulable_list.hh"
#include "schedulable_status.hh"
#include "../templates/smartp.hh"

namespace sgpem
{

  /**	\brief Manages the history of the simulation 
	
	Manages the history of the simulation from the instant 0 to the current time,
	i.e. permits to know the state of each schedulable object inside this time interval.
	In particoular it's possible to know which entity was running at a precise moment.
	
	In a future iteration it will be possible to revert the entire simulation to a state
	present in the history ("undo operation")
 
  */
  class History;
	
  class SG_DLLEXPORT History : public ObservedSubject 
  {
  public:
				
    memory::smart_ptr<sgpem::SchedulableStatus>			get_scheduled_at(int time) const;
	memory::smart_ptr<sgpem::SchedulableList>		 	get_simulation_status_at(int time) const;
    int  												get_current_time() const;
	void												enqueue_slice(const sgpem::SchedulableList& status);	
    void 												truncate_at(int instant);
		
    static History&  									get_instance();
			
  private:
    History(int);					//private constructor. The parameter is discarded
    static History  _instance;
    int             _total_time_elapsed;
    std::vector<sgpem::Slice>	_slices;
  };
	
}//~ namespace sgpem

#endif //HISTORY_H