:- module(agent, [init, look/0, move/1, take/1]).


:- consult('parser.prolog').
:- consult('map.prolog').




% initialisation

init :-
    initPos,
    initPits,
    initWumpus,
    initGold,
    initBats, !.


initPos :-
    retractall(here(_)),
    roomList(Rooms),
    filter(Rooms, somethingAt, Emptyrooms),
    random_member(X,Emptyrooms),
    asserta(here(X)).


initPits :- true.


initWumpus :-
    retractall(wumpusAt(_)),
    roomList(Rooms),
    filter(Rooms, somethingAt, Emptyrooms),
    random_member(X,Emptyrooms),
    asserta(wumpusAt(X)).


initGold :- true.


initBats :- true.




% command functions

look :-
    here(Location),
    writeSenses(Location),
    writeExits(Location).


move(Direction) :-
    here(Location),
    connects(Location, New, Direction),
    retract(here(Location)),
    asserta(here(New)),
    join(['You move to the ',Direction,' .\n\n'],W),
    write(W), !.


take(Item) :-
    here(Location),
    itemAt(Item,Location),
    canTake(Item),
    retract(itemAt(Item,Location)),
    asserta(holding(Item)),
    write('Taken.\n\n'), !.




% letting the player know what's going on

writeSenses(Location) :-
    glitter(Location),
    breeze(Location),
    bats(Location),
    stench(Location).


glitter(Location) :-
    current_predicate(goldAt/1),
    goldAt(Location),
    write('You see a glitter along the sandy floor of the cave.\n').
glitter(_) :- true.


breeze(Location) :-
    current_predicate(pitAt/1),
    connects(Location, ConnectedRoom, _),
    pitAt(ConnectedRoom),
    write('A cold breeze blows through the room, making you shiver slightly.\n').
breeze(_) :- true.


bats(Location) :-
    current_predicate(batsAt/1),
    connects(Location, ConnectedRoom, _),
    batsAt(ConnectedRoom),
    write('All available surfaces are covered in guano. How unsanitary.\n').
bats(_) :- true.


stench(Location) :-
    current_predicate(wumpusAt/1),
    connects(Location, ConnectedRoom, _),
    wumpusAt(ConnectedRoom),
    write('An overpowering stench fills your nose.\n').
stench(_) :- true.


writeExits(Location) :-
    findall(X, connects(Location,_,X), Exits),
    intercalate(Exits, ', ', O),
    join(['There are exits to the ',O,'.\n'],W),
    write(W).




% miscellaneous clauses

somethingAt(X) :- current_predicate(here/1), here(X).
somethingAt(X) :- current_predicate(wumpusAt/1), wumpusAt(X).
somethingAt(X) :- current_predicate(pitAt/1), pitAt(X).
somethingAt(X) :- current_predicate(goldAt/1), goldAt(X).
somethingAt(X) :- current_predicate(batsAt/1), batsAt(X).


intercalate([X|Y], Spacer, Result) :-
    intercalate(Y, Spacer, Tail),
    atom_concat(X, Spacer, Head),
    atom_concat(Head, Tail, Result).
intercalate([X], _, Result) :- Result = X.


filter(List, Predicate, Result) :-
    Test =.. [Predicate,X],
    findall(X, Test, No),
    subtract(List, No, Result).