// 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 "ready_queue.hh"
#include "dynamic_schedulable.hh"
#include "smartp.hh"

// Do not include complete template definition here:
#include "singleton.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 Singleton<History>, public ObservedSubject
  {
    friend class Singleton<History>;

  public:
    /**
     Gets the \ref Schedulable object running at the specified time.
     \param time The inquired time instant.
     \return The Schedulable object running at the given time.
     */
    virtual memory::smart_ptr<sgpem::DynamicSchedulable> get_scheduled_at(int time) const;

    /**
     Gets the status of simulation at the specified time.
     \param time The inquired time instant.
     \return The list of Schedulable status objects at the specified time.
     */
    virtual memory::smart_ptr<sgpem::ReadyQueue> get_simulation_status_at(int time) const;

    /**
     Gets the current time.
     \return The current history time.
     */
    virtual int get_current_time() const;

    /**
     Sets the status of simulation at the current time.
     \param status The list of \ref Schedulable status objects at the current time.
     */
    virtual void enqueue_slice(const sgpem::ReadyQueue& status);

    /**
     Remove all data in History following the specified time.
     \param instant Desired cutting time.
     */
    virtual void truncate_at(int instant);

  protected:
    History();   //private constructor.
    History(const History&);
    History& operator=(const History&);

  private:
    int             _total_time_elapsed;
    std::vector<sgpem::Slice> _slices;
  };

}//~ namespace sgpem

#endif //HISTORY_H