:- module(grid,
          [ query/2,
            shoot/1,
            revive/0
          ]).
:- (dynamic shot/2).
:- (dynamic failed/2).
:- use_module(library(lists)).

revive :-
    retractall(shot(_, _)),
    retractall(failed(_, _)).
    

shoot((_, _)) :-
    shot(_, _), !,
    write("\nAlready shot!\n"),
    fail.
shoot((X, Y)) :-
    format('~nPang! You shot at ~q~n', [(X, Y)]),
    assert(shot(X, Y)).

query((_, _), []) :-
    failed(X, Y),
    format('~nAgent has been lost at ~q, (`revive.` to continue)~n',
           [(X, Y)]), !,
    fail.


query((X, Y), Out2) :-
    integer(X),
    integer(Y),
    %DB=[[[], [], [], [stench]], [[], [], [breeze, stench], [wumpus]], [[], [breeze], [pit], [breeze, stench]], [[], [], [glitter], []]], 
    %DB=[[[], [], ['stench'], ['wumpus']], [[], [], [], ['stench']], [[], [], ['breeze'], ['glitter']], [[], ['breeze'], ['pit'], ['breeze']]],
    %DB=[[[], ['breeze'], [], []], [['stench', 'breeze'], ['pit'], ['breeze'], []], [['wumpus'], ['stench', 'breeze'], [], []], [['stench', 'glitter'], [], [], []]], % not found
    %DB=[[[], ['glitter'], [], []], [[], ['stench'], ['breeze'], []], [['stench'], ['wumpus', 'breeze'], ['stench', 'pit'], ['breeze']], [[], ['stench'], ['breeze'], []]],
    DB=[[[], [], [], []], [[], ['stench'], ['breeze'], []], [['stench'], ['wumpus', 'breeze'], ['stench', 'pit'], ['breeze']], [['glitter'], ['stench'], ['breeze'], []]],
    nth0(Y, DB, Row), nth0(X, Row, Found),
    format('~nInvestigating ~q,~nfound: ~q~n',
           [(X, Y), Found]),
    (   (   member(wumpus, Found),
            \+ shot(X, Y)
        ;   member(pit, Found)
        )
    ->  write("FAIL"),
        assert(failed(X, Y)),
        fail
    ;   true
    ),
    clean_query(Found, Out),
    maplist({X, Y}/[I, O]>>(O=..[I,  (X, Y)]),
            Out,
            Out2), !.

clean_query(In, Out) :-
    clean_breeze(In, Out1),
    clean_stench(Out1, Out2),
    clean_glitter(Out2, Out).

clean_breeze(In, In) :-
    member(breeze, In).
clean_breeze(In, [no_breeze|In]) :-
    \+ member(breeze, In).

clean_stench(In, In) :-
    member(stench, In).
clean_stench(In, [no_stench|In]) :-
    \+ member(stench, In).

clean_glitter(In, In) :-
    member(glitter, In).
clean_glitter(In, [no_glitter|In]) :-
    \+ member(glitter, In).