#include <hash_map>

#include "message.h"

#ifndef GHOST_LINK_H
#define GHOST_LINK_H

using namespace std;

// WARNING: The Link system relies on bound member functions, a g++ extended feature,
// you must compile with -Wno-pmf-conversions.

// TODO change to use input and output operators?  <<  >>

template <>
struct hash<void*> {
	size_t operator()(void* __x) const { return (size_t)__x; }
};

class _Link {
public:
	typedef void (*sig_h_t)(void *);
	void *m;
	void *data; // this is closure data - can be a void * or an int - TODO nice way to get an int into it?
	sig_h_t signal_h;

	_Link(void *data) : data(data) {}
};

typedef hash_map<void *, _Link *> links_t;

links_t links;

template <class O, class M>
class Link : _Link {
public:
	typedef void (M::*member_t)();
	typedef void (*func_t)(M *);

	O& o;

	Link(O& object, M* machine, member_t signal, void *data = 0) : o(object), _Link(data) {
		hash_map<void *, _Link *>::iterator it = links.find(&o);
		if (it == links.end()) {
			links[&object] = this;
			m = machine;
			signal_h = (sig_h_t)(func_t)(machine->*signal);
		} else {
			_Link *peer_link = it->second;
			if (peer_link == 0) {
				fatal("already linked");
			} else {
				m = peer_link->m;
				signal_h = peer_link->signal_h;
				peer_link->m = machine;
				peer_link->signal_h = (sig_h_t)(func_t)(machine->*signal);
				it->second = 0;
			}
		}
	}

	void signal() {
		(*signal_h)(m);
	}
};

#endif