/*
 Deterministcally table a predicate of the form
  K -> RV

  where the K are the first N-1 arguments.

  Note that this does not include support for backtracking
*/

:- module(clpbn_table,
	[clpbn_table/1,
	 clpbn_tableallargs/1,
	 clpbn_table_nondet/1,
	 clpbn_tabled_clause/2,
	 clpbn_tabled_abolish/1,
	 clpbn_tabled_asserta/1,
	 clpbn_tabled_assertz/1,
	 clpbn_tabled_asserta/2,
	 clpbn_tabled_assertz/2,
	 clpbn_tabled_dynamic/1,
	 clpbn_tabled_number_of_clauses/2,
	 clpbn_reset_tables/0,
	 clpbn_reset_tables/1,
	 clpbn_is_tabled/1
	]).

:- use_module(library(bhash),
	[b_hash_new/4,
	 b_hash_lookup/3,
	 b_hash_insert/4]).

:- meta_predicate clpbn_table(:),
	clpbn_tabled_clause(:.?),
	clpbn_tabled_abolish(:),
	clpbn_tabled_asserta(:), 
	clpbn_tabled_assertz(:), 
	clpbn_tabled_asserta(:,-), 
	clpbn_tabled_assertz(:,-), 
	clpbn_tabled_number_of_clauses(:,-), 
	clpbn_is_tabled(:).

:- use_module(library(terms), [
			       instantiated_term_hash/4,
			       variant/2
			       ]).

:- dynamic clpbn_table/3.

:- meta_predicate clpbn_table(:), clpbn_table_all_args(:).

:- initialization(init).

init :-
	clpbn_reset_tables.

clpbn_reset_tables :-
	clpbn_reset_tables(2048).

clpbn_reset_tables(Sz) :-
	b_hash_new(Tab, Sz, myf, myc),
	nb_setval(clpbn_tables, Tab).

myf(Key, Size, Index) :-
	instantiated_term_hash(Key, -1, Size, Index).

myc(A, B) :-
	variant(A,B),
	term_variables(A,L1),
	term_variables(B,L2),
	match_keys(L1,L2).

match_keys([],[]).
match_keys([V1|L1],[V2|L2]) :-
	clpbn:get_atts(V1,[key(K)]),
	clpbn:get_atts(V2,[key(K)]),
	match_keys(L1,L2).


clpbn_table(M:X) :- !,
	clpbn_table(X,M).
clpbn_table(X) :-
	prolog_load_context(module, M),
	clpbn_table(X,M).

clpbn_table(M:X,_) :- !,
	clpbn_table(X,M).
clpbn_table((P1,P2),M) :- !,
	clpbn_table(P1,M),
	clpbn_table(P2,M).
clpbn_table(F/N,M) :-
	functor(S,F,N),
	S =.. L0,
	take_tail(L0, V, L1, V, L2),
	Key =.. L1,
	atom_concat(F, '___tabled', NF),
	L2 = [_|Args],
	S1 =.. [NF|Args],
	L0 = [_|OArgs],
	S2 =.. [NF|OArgs],
	asserta(clpbn_table(S, M, S2)),
	assert(
	       (M:S :-
	        b_getval(clpbn_tables, Tab),
		( b_hash_lookup(Key, V1, Tab) ->
		  V1=V
		;
		  b_hash_insert(Tab, Key, V, NewTab),
		  b_setval(clpbn_tables,NewTab),
		  once(M:S2)
		)
	       )
	      ).

take_tail([V], V, [], V1, [V1]) :- !.
take_tail([A|L0], V, [A|L1], V1, [A|L2]) :-
	take_tail(L0, V, L1, V1, L2).

clpbn_tableallargs(M:X) :- !,
	clpbn_tableallargs(X,M).
clpbn_tableallargs(X) :-
	prolog_load_context(module, M),
	clpbn_tableallargs(X,M).

clpbn_tableallargs(M:X,_) :- !,
	clpbn_tableallargs(X,M).
clpbn_tableallargs((P1,P2),M) :- !,
	clpbn_tableallargs(P1,M),
	clpbn_tableallargs(P2,M).
clpbn_tableallargs(F/N,M) :-
	functor(Key,F,N),
	Key =.. [F|Args],
	atom_concat(F, '___tabled', NF),
	NKey =.. [NF|Args],
	asserta(clpbn_table(Key, M, NKey)),
	assert(
	       (M:Key :-
	        b_getval(clpbn_tables, Tab),
		( b_hash_lookup(Key, Out, Tab) ->
		  true
		;
		  b_hash_insert(Tab, Key, Out, NewTab),
	          b_setval(clpbn_tables, NewTab),
		  once(M:NKey)
		)
	       )
	      ).

clpbn_table_nondet(M:X) :- !,
	clpbn_table_nondet(X,M).
clpbn_table_nondet(X) :-
	prolog_load_context(module, M),
	clpbn_table_nondet(X,M).

clpbn_table_nondet(M:X,_) :- !,
	clpbn_table_nondet(X,M).
clpbn_table_nondet((P1,P2),M) :- !,
	clpbn_table_nondet(P1,M),
	clpbn_table_nondet(P2,M).
clpbn_table_nondet(F/N,M) :-
	functor(Key,F,N),
	Key =.. [F|Args],
	atom_concat(F, '___tabled', NF),
	NKey =.. [NF|Args],
	asserta(clpbn_table(Key, M, NKey)),
	assert(
	       (M:Key :- writeln(in:Key),
	        b_getval(clpbn_tables, Tab),
		( b_hash_lookup(Key, Out, Tab) ->
		  fail
		;
		  b_hash_insert(Tab, Key, Out, NewTab),
	          b_setval(clpbn_tables, NewTab),
		  M:NKey
		)
	       )
	      ).

user:term_expansion((P :- Gs), NC) :-
	clpbn_table(P, M, NP),
	prolog_load_context(module, M), !,
	assert(M:(NP :- Gs)),
	NC = (:-true).

in_table(K, V) :-
	b_getval(clpbn_tables, Tab),
	b_hash_lookup(K, V, Tab).

store_in_table(K, V) :-
	b_getval(clpbn_tables, Tab),
	b_hash_insert(Tab, K, V).

clpbn_tabled_clause(M:Head, Body) :- !,
	clpbn_tabled_clause(Head, M, Body).
clpbn_tabled_clause(Head, Body) :-
	prolog_load_context(module, M),
	clpbn_tabled_clause(Head, M, Body).

clpbn_tabled_clause(M:Head, _, Body) :- !,
	clpbn_tabled_clause(Head, M, Body).
clpbn_tabled_clause(Head, M, Body) :-
	clpbn_table(Head, M, THead),
	clause(M:THead, Body).


clpbn_tabled_assertz(M:Clause) :- !,
	clpbn_tabled_assertz2(Clause, M).
clpbn_tabled_assertz(Clause) :-
	prolog_load_context(module, M),
	clpbn_tabled_assertz2(Clause, M).

clpbn_tabled_assertz2(M:Clause, _) :- !,
	clpbn_tabled_assertz2(Clause, M).
clpbn_tabled_assertz2((Head:-Body), M) :- !,
	clpbn_table(Head, M, THead),
	assertz(M:(THead :- Body)).
clpbn_tabled_assertz2(Head, M) :-
	clpbn_table(Head, M, THead),
	assertz(THead).

clpbn_tabled_assertz(M:Clause, Ref) :- !,
	clpbn_tabled_assertz2(Clause, M, Ref).
clpbn_tabled_assertz(Clause, Ref) :-
	prolog_load_context(module, M),
	clpbn_tabled_assertz2(Clause, M, Ref).

clpbn_tabled_assertz2(M:Clause, _, Ref) :- !,
	clpbn_tabled_assertz2(Clause, M, Ref).
clpbn_tabled_assertz2((Head:-Body), M, Ref) :- !,
	clpbn_table(Head, M, THead),
	assertz(M:(THead :- Body), Ref).
clpbn_tabled_assertz2(Head, M, Ref) :-
	clpbn_table(Head, M, THead, Ref),
	assertz(THead).


clpbn_tabled_asserta(M:Clause) :- !,
	clpbn_tabled_asserta2(Clause, M).
clpbn_tabled_asserta(Clause) :-
	prolog_load_context(module, M),
	clpbn_tabled_asserta2(Clause, M).

clpbn_tabled_asserta2(M:Clause, _) :- !,
	clpbn_tabled_asserta2(Clause, M).
clpbn_tabled_asserta2((Head:-Body), M) :- !,
	clpbn_table(Head, M, THead),
	asserta(M:(THead :- Body)).
clpbn_tabled_asserta2(Head, M) :-
	clpbn_table(Head, M, THead),
	asserta(THead).

clpbn_tabled_asserta(M:Clause, Ref) :- !,
	clpbn_tabled_asserta2(Clause, M, Ref).
clpbn_tabled_asserta(Clause, Ref) :-
	prolog_load_context(module, M),
	clpbn_tabled_asserta2(Clause, M, Ref).

clpbn_tabled_asserta2(M:Clause, _, Ref) :- !,
	clpbn_tabled_asserta2(Clause, M, Ref).
clpbn_tabled_asserta2((Head:-Body), M, Ref) :- !,
	clpbn_table(Head, M, THead),
	asserta(M:(THead :- Body), Ref).
clpbn_tabled_asserta2(Head, M, Ref) :-
	clpbn_table(Head, M, THead, Ref),
	asserta(THead).


clpbn_tabled_abolish(M:Clause) :- !,
	clpbn_tabled_abolish(Clause, M).
clpbn_tabled_abolish(Clause) :-
	prolog_load_context(module, M),
	clpbn_tabled_abolish(Clause, M).

clpbn_tabled_abolish(M:Clause, _) :- !,
	clpbn_tabled_abolish(Clause, M).
clpbn_tabled_abolish(N/A, M) :-
	functor(Head, N, A),
	clpbn_table(Head, M, THead),
	functor(THead, TN, A),
	abolish(M:TN/A).

clpbn_tabled_dynamic(M:Clause) :- !,
	clpbn_tabled_dynamic(Clause, M).
clpbn_tabled_dynamic(Clause) :-
	prolog_load_context(module, M),
	clpbn_tabled_dynamic(Clause, M).

clpbn_tabled_dynamic(M:Clause, _) :- !,
	clpbn_tabled_dynamic(Clause, M).
clpbn_tabled_dynamic(N/A, M) :-
	functor(Head, N, A),
	clpbn_table(Head, M, THead),
	functor(THead, TN, A),
	dynamic(M:TN/A).

clpbn_tabled_number_of_clauses(M:Clause, N) :- !,
	clpbn_tabled_number_of_clauses(Clause, M, N).
clpbn_tabled_number_of_clauses(Clause, N) :-
	prolog_load_context(module, M),
	clpbn_tabled_number_of_clauses(Clause, M, N).

clpbn_tabled_number_of_clauses(M:Clause, _, N) :- !,
	clpbn_tabled_number_of_clauses(Clause, M, N).
clpbn_tabled_number_of_clauses(Head, M, N) :-
	clpbn_table(Head, M, THead),
	predicate_property(M:THead,number_of_clauses(N)).


clpbn_is_tabled(M:Clause) :- !,
	clpbn_is_tabled(Clause, M).
clpbn_is_tabled(Clause) :-
	prolog_load_context(module, M),
	clpbn_is_tabled(Clause, M).

clpbn_is_tabled(M:Clause, _) :- !,
	clpbn_is_tabled(Clause, M).
clpbn_is_tabled(Head, M) :-
	clpbn_table(Head, M, _).