% Dinko Korunic, kreator@srk.fer.hr
% Tue Jan 22 10:37:27 CET 2002
% vim: set syntax=off:ts=2:sw=2:

:- module(world,[
  world_create/1,
  world_symbol_pit/1,
  world_symbol_wumpus_alive/1,
  world_symbol_wumpus_dead/1, 
  world_symbol_gold/1,
  world_symbol_agent/1,
  world_get/4,
  world_set/5,
  world_legal/3,
  world_print/1,
  world_get_symbols/5]).

:-use_module('array.pl').

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% creation
world_create(W4):-
  array_create(4,5,[],W),
  array_height(W,M),
  array_width(W,N),
  world_legal(W,M,N),
  world_set(W,1,1,a,W1),
  world_set_wumpus(W1,4,5,W2),
  world_set_gold(W2,4,5,W3),
  world_set_pit(W3,4,5,W4).
  
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% attributes
world_symbol_pit(p).
world_symbol_wumpus_alive(wa).
world_symbol_wumpus_dead(wd).
world_symbol_gold(g).
world_symbol_agent(a).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% operations

% print world - call array:print/1
world_print(W):-
  array_print(W).

% randomize any item, don't use 1:1
world_randomize_item(MaxM,MaxN,M,N):-
  M is random(MaxM)+1,
  N is random(MaxN)+1,
  (M=\=1;N=\=1),!;
  world_randomize_item(MaxM,MaxN,M,N).

% set wumpus in the world
world_set_wumpus(W1,M1,N1,W2):-
  world_randomize_item(M1,N1,M,N),
  world_symbol_wumpus_alive(WA),  
  world_set(W1,M,N,WA,W2).

% set some gold in the world
world_set_gold(W1,M1,N1,W2):-
  world_randomize_item(M1,N1,M,N),
  world_symbol_gold(G),
  world_set(W1,M,N,G,W2).

% set a pit in the world
world_set_pit(W,M,N,W1):-
  I is M*N-1,
  world_set_pits(I,M,N,W,W1).
world_set_pits(-1,_,_,W,W).
world_set_pits(I,M,N,W,W2):-
  Y is (I//M)+1,
  X is (I mod M)+1,
  world_put_pit(X,Y,W,W1),
  J is I-1,
  world_set_pits(J,M,N,W1,W2).
world_put_pit(X,Y,W,W1):-
  world_symbol_pit(P),
  (random(5)=:=3,
  world_set(W,X,Y,P,W1));
  W1=W.

% check if the world is legal
world_legal(W,M,N):-
  array_legal(W,M,N).

% set an item in the world
world_set(A,M,N,I,A1):-
  array_get(A,M,N,I1),
  array_set(A,M,N,[I|I1],A1).

% get an item from the world
world_get(A,M,N,I):-
  array_get(A,M,N,I).

% get all symbols
world_get_symbols(P,WA,WD,G,A):-
  world_symbol_pit(P),
  world_symbol_wumpus_alive(WA),
  world_symbol_wumpus_dead(wd),
  world_symbol_gold(G),
  world_symbol_agent(A).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% world setup and display
goal:-
  world_create(W),
  world_print(W).