tictactoe.erl

-module(tictactoe).
-export([start/1]).
-import(random).

start(Inputs) ->
  Board = lists:nth(1, Inputs),
  Piece = whoAmI(Board),
  ValidMoves = freeSpaces(Board),
  Move = selectBestMove(ValidMoves, Piece, Board),
  io:format(integer_to_list(Move)),
  erlang:halt().

selectBestMove(ValidMoves, Piece, Board) ->
  WeightedMoves = weightedMoves(Piece, ValidMoves, Board),
  lists:nth(1, WeightedMoves) - 1.

weightedMoves(Piece, ValidMoves, Board) ->
  lists:map(fun(Move)
      %NewBoard = Board[Move] = Piece,
      rank(Piece, NewBoard)
    end, ValidMoves)

rank(Piece, Board) ->
  win(Piece, Board) + blockLoss(Piece, Board) + fork(Piece, Board).

fork(Piece, Board) ->
  0.

win(Piece, Board) ->
  if
    str(Board, "ooo") =/= 0 ->
      1;
    true ->
      0;
  end.

blockLoss(Piece, Board) ->
  0.

freeSpaces(Board) ->
  AllMoves = lists:seq(1, 9),
  lists:filter(
  fun(Item) ->
    Char = lists:nth(Item, Board),
    if
       Char =:= $- ->
        true;
      true ->
        false
    end
  end, AllMoves).

whoAmI(Board) ->
  NumO = frequencyCount($o, Board),
  NumX = frequencyCount($x, Board),
	if
	  (NumO > NumX) ->
			x;
	  true ->
	    whoAmI(NumO, NumX)
	end.

%This is really my inability to get nested if loops to be syntaxtically correct
whoAmI(NumO, NumX) ->
  if
    NumO =:= NumX ->
      o;
    true ->
      x
  end.

frequencyCount(Char, Board) ->
    lists:foldl(fun(X, Sum) ->
    if
      X =:= Char -> Sum + 1;
      true -> Sum + 0
    end
  end, 0, Board).

dumpList(List) ->
  io:format(lists:map(fun(X) -> integer_to_list(X) end, List)).