StateStack.hpp

#ifndef STATE_STACK_HPP
#define STATE_STACK_HPP

#include <SFML/System.hpp>

#include <map>
#include <vector>
#include <functional>
#include <cassert>

#include "State.hpp"
#include "StateIdentifiers.hpp"


class StateStack : private sf::NonCopyable
{
public:
	enum Action
	{
		Push,
		Pop,
		Clear,
	};

public:
	explicit StateStack(State::Context context);

	template <typename T>
	void registerState(States::ID stateID);

	void update(sf::Time dt);
	void draw();
	void handleEvent(const sf::Event &event);

	void pushState(States::ID stateID);
	void popState();
	void clearStates();

	bool isEmpty() const;

private:
	State::Ptr createState(States::ID stateID);
	void applyPendingChanges();

private:
	struct PendingChange
	{
		explicit PendingChange(Action action, States::ID stateID = States::None);
		Action 		action;
		States::ID 	stateID;
	};
private:
	std::vector<State::Ptr> 	mStack;
	std::vector<PendingChange>	mPendingList;
	State::Context				mContext;
	std::map<States::ID, std::function<State::Ptr()> > mFactories;
};
 
template <typename T>
void StateStack::registerState(States::ID stateID)
{
	mFactories[stateID] = [this] ()
	{
		return State::Ptr(new T(*this, mContext));
	};
}

#endif