// 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 "environment.hh"

#include <glibmm/ustring.h>

#include <stdexcept>
#include <utility>
#include <vector>


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;

	// Forward declarations:
	class HistoryObserver;
	class Resource;
	class Process;
	class Thread;
	class Request;
	class SubRequest;

  class SG_DLLEXPORT History
  {
  public:
		typedef unsigned int                     size_t;
		typedef unsigned int                     time_t;
		typedef unsigned int                     position;
		typedef int                              prio_t;

		typedef Environment::resource_key_t      resource_key_t;
		typedef const std::pair<resource_key_t, Resource*>  ResourcePair;

  	virtual ~History() = 0;
		
		virtual       size_t       get_size() = 0;
		virtual const Environment& get_last_environment() const = 0;
		virtual const Environment& get_environment_at(position index) const throw(std::out_of_range) = 0;
		
		virtual void  remove(resource_key_t resource_key)  = 0;
		virtual void  remove(Process&    process)          = 0;
		virtual void  remove(Thread&     thread)           = 0;
		virtual void  remove(Request&    request)          = 0;
		virtual void  remove(SubRequest& subrequest)       = 0;


		virtual ResourcePair add_resource(const Glib::ustring& name,
																			 bool   preemptable  = false,
																			 size_t places       = 1,
																			 size_t availability = 0) = 0;

		virtual Process&     add_process(const Glib::ustring& name,
																		 time_t arrival_time,
																		 prio_t base_priority = 0) = 0;

		virtual Thread&      add_thread(const Glib::ustring& name,
																		Process& parent,
																		time_t cpu_time,
																		time_t arrival_time = 0,
																		prio_t base_priority = 0) = 0;

		virtual Request&     add_request(Thread& owner,
																		 time_t instant) = 0;

		virtual SubRequest&  add_subrequest(Request& request,
																				resource_key_t resource_key,
																				time_t  duration,
																				size_t  places = 1) = 0;


		virtual void  attach(HistoryObserver& observer);
		virtual void  detach(const HistoryObserver& observer);
		
	protected:
		typedef std::vector<HistoryObserver*> RegisteredObservers;
		RegisteredObservers _observers;

		virtual void notify_change();
				
  }; //~ class History

}//~ namespace sgpem

#endif //~ HISTORY_HH