#include <lua.h>
#include <lauxlib.h>
#include <honeysuckle.h>

void append_table(lua_State *L, int tbl_a, int tbl_b)
{
	lua_pushnil(L);
	while(lua_next(L, tbl_b) != 0) {
		lua_pushvalue(L, -2); // key
		lua_pushvalue(L, -2); // value
		lua_settable(L, tbl_a);
		lua_pop(L, 1);
	}
}


const char *canary_tname = "honey.canary";

int gc_canary(lua_State *L);
int gc_canary_collect(lua_State *L);

void setup_util(lua_State *L, int honey_tbl)
{
	/* create gc_canary metatable */
	luaL_newmetatable(L, canary_tname);
	lua_pushcfunction(L, gc_canary_collect);
	lua_setfield(L, -2, "__gc");
	lua_pop(L, 1);

	hs_create_table(L,
		hs_str_cfunc("gc_canary", gc_canary),
	);

	lua_setfield(L, honey_tbl, "util");
}


int gc_canary(lua_State *L)
{
	luaL_checktype(L, 1, LUA_TFUNCTION);
	int ref = luaL_ref(L, LUA_REGISTRYINDEX);
	int *canary = lua_newuserdata(L, sizeof(int));
	*canary = ref;
	luaL_getmetatable(L, canary_tname);
	lua_setmetatable(L, -2);
	return 1;
}


int gc_canary_collect(lua_State *L)
{
	int *canary = luaL_checkudata(L, 1, canary_tname);
	lua_rawgeti(L, LUA_REGISTRYINDEX, *canary);
	lua_call(L, 0, 0);
	luaL_unref(L, LUA_REGISTRYINDEX, *canary);
	return 0;
}