// Cyphesis Online RPG Server and AI Engine
// Copyright (C) 2000-2004 Alistair Riddoch
//
// This program 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.
// 
// This program 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 this program; if not, write to the Free Software Foundation,
// Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA


#ifndef RULESETS_BASE_WORLD_H
#define RULESETS_BASE_WORLD_H

#include "common/Singleton.h"

#include "modules/Ref.h"

#include "rules/simulation/LocatedEntity.h"

#include <Atlas/Objects/ObjectsFwd.h>

#include <sigc++/signal.h>

#include <chrono>
#include <set>
#include <functional>

template<typename EntityT>
class Location;

typedef std::map<long, Ref<LocatedEntity>> EntityRefDict;

/// \brief Base class for game world manager object.
///
/// This base class provides the common features required by cyphesis
/// for the object which encapsulates the game world. Other classes
/// inherit from this provide the core game world system.
class BaseWorld : public Singleton<BaseWorld> {
public:
	typedef std::function<std::chrono::steady_clock::duration()> TimeProviderFnType;

protected:

	TimeProviderFnType m_timeProviderFn;
	/// The system time when the server was started.
	std::chrono::steady_clock::time_point m_initTime;

	/// \brief Dictionary of all the objects in the world.
	///
	/// Pointers to all in-game entities in the world are stored keyed to
	/// their integer ID.
	EntityRefDict m_eobjects;

	/// \brief Whether the base world is suspended or not.
	///
	/// If this is set to true, the world is "suspended". In this state no
	/// Tick ops are sent.
	/// This is useful for when a world author wants to edit the world
	/// without the simulation altering it.
	bool m_isSuspended;

	std::map<std::string, LocatedEntity*> m_entityAliases;

	explicit BaseWorld(TimeProviderFnType timeProviderFn);

	/// \brief Called when the world is resumed.
	virtual void resumeWorld() {}

public:

	~BaseWorld() override;

	/**
	 * Shuts down the simulation and frees up all entities.
	 */
	virtual void shutdown();

	Ref<LocatedEntity> getEntity(const std::string& id) const;

	Ref<LocatedEntity> getEntity(long id) const;

	/// \brief Read only accessor for the in-game objects dictionary.
	const EntityRefDict& getEntities() const {
		return m_eobjects;
	}

	void registerAlias(std::string alias, LocatedEntity& entity);

	void deregisterAlias(const std::string& alias, LocatedEntity& entity);

	LocatedEntity* getAliasEntity(const std::string& alias) const;

	/// \brief Read only accessor for the in-game time.
	std::chrono::steady_clock::duration getTime() const;

	std::chrono::milliseconds getTimeAsMilliseconds() const;

	float getTimeAsSeconds() const;

	/// \brief Get the time the world has been running since the server started.
	double upTime() const {
		return getTimeAsSeconds();
	}

	/// \brief Gets whether the world is suspended or not.
	const bool& getIsSuspended() const {
		return m_isSuspended;
	}

	/// \brief Sets whether the world is suspended or not.
	/// If this is set to true, the world is "suspended". In this state no
	/// Tick ops are sent.
	/// This is useful for when a world author wants to edit the world
	/// without the simulation altering it.
	void setIsSuspended(bool suspended);

	/// \brief Add a new entity to the world.
	virtual void addEntity(const Ref<LocatedEntity>& obj, const Ref<LocatedEntity>& parent) = 0;

	/// \brief Create a new entity and add to the world.
	virtual Ref<LocatedEntity> addNewEntity(const std::string& type,
											const Atlas::Objects::Entity::RootEntity&) = 0;

	/// \brief Deletes an entity from the world.
	virtual void delEntity(LocatedEntity* obj) = 0;

	virtual const std::set<std::string>& getSpawnEntities() const = 0;

	virtual void registerSpawner(const std::string& id) = 0;

	virtual void unregisterSpawner(const std::string& id) = 0;

	/// \brief Pass an operation to the world.
	virtual void message(Atlas::Objects::Operation::RootOperation,
						 LocatedEntity& obj) = 0;

	/// \brief Find an entity of the given name.
	virtual Ref<LocatedEntity> findByName(const std::string& name) = 0;

	/// \brief Find an entity of the given type.
	virtual Ref<LocatedEntity> findByType(const std::string& type) = 0;

	/// \brief Signal that an operation is being dispatched.
	sigc::signal<void(Atlas::Objects::Operation::RootOperation)> Dispatching;
};

#endif // RULESETS_BASE_WORLD_H
