arg(1, Space, Atoms),
    length(Atoms, Count).

% Remove an atom from a space
remove_nb_atom(SpaceNameOrInstance, Atom) :-
    fetch_or_create_space(SpaceNameOrInstance, Space),
    arg(1, Space, Atoms),
    select(Atom, Atoms, UpdatedAtoms),
    nb_setarg(1, Space, UpdatedAtoms).

% Fetch all atoms from a space
get_nb_atoms(SpaceNameOrInstance, Atoms) :-
    fetch_or_create_space(SpaceNameOrInstance, Space),
    arg(1, Space, Atoms).

% Replace an atom in the space
replace_nb_atom(SpaceNameOrInstance, OldAtom, NewAtom) :-
    fetch_or_create_space(SpaceNameOrInstance, Space),
    arg(1, Space, Atoms),
    ( (select(Found, Atoms, TempAtoms),OldAtom=@=Found)
    ->  NewAtoms = [NewAtom | TempAtoms],
        nb_setarg(1, Space, NewAtoms)
    ;   false
    ).



% Function to confirm if a term represents a space
is_valid_nb_space(Space):- compound(Space),functor(Space,'Space',_).

% Find the original name of a given space
space_original_name(Space, Name) :-
    is_registered_space_name(Name),
    nb_current(Name, Space).

% Register and initialize a new space
init_space(Name) :-
    Space = 'Space'([]),
    asserta(is_registered_space_name(Name)),
    nb_setval(Name, Space).

fetch_or_create_space(Name):- fetch_or_create_space(Name,_).
% Fetch an existing space or create a new one
fetch_or_create_space(NameOrInstance, Space) :-
    (   atom(NameOrInstance)
    ->  (is_registered_space_name(NameOrInstance)
        ->  nb_current(NameOrInstance, Space)
        ;   init_space(NameOrInstance),
            nb_current(NameOrInstance, Space))
    ;   is_valid_nb_space(NameOrInstance)
    ->  Space = NameOrInstance
    ;   writeln('Error: Invalid input.')
    ),
    is_valid_nb_space(Space).


% Match Pattern in Space and produce Template
'match'(Space, Pattern, Template) :-
    'get-atoms'(Space, Atoms),
    'match-pattern'(Atoms, Pattern, Template).

% Simple pattern match
'match-pattern'([], _, []).
'match-pattern'([H |_T], H, H) :- !.
'match-pattern'([_H| T], Pattern, Template) :- 'match-pattern'(T, Pattern, Template).

%is_python_space(X):- python_object(X).

ensure_space(X,Y):- catch(ensure_space_py(X,Y),_,fail),!.
ensure_space(_N,_V):- fail.

% ===============================
% Clause Database interface
% ===============================
%dout(space,Call):- skip(Call).
if_metta_debug(Goal):- getenv('VSPACE_VERBOSE','2'),!,ignore(call(Goal)).
if_metta_debug(_):-!.
if_metta_debug(Goal):- !,ignore(call(Goal)).
dout(_,_):-!.
dout(W,Term):- notrace(if_metta_debug((format('~N; ~w ~@~n',[W,write_src(Term)])))).

:- multifile(space_type_method/3).
:- dynamic(space_type_method/3).
space_type_method(is_asserted_space,new_space,init_space).
space_type_method(is_asserted_space,clear_space,clear_nb_atoms).
space_type_method(is_asserted_space,add_atom,metta_assertdb_add).
space_type_method(is_asserted_space,remove_atom,metta_assertdb_rem).
space_type_method(is_asserted_space,replace_atom,metta_assertdb_replace).