1 function winner(board)

     2 {

     3     for (var i=0; i<3; ++i) {

     4         if (board.children[i].state!=""

     5             && board.children[i].state==board.children[i+3].state

     6             && board.children[i].state==board.children[i+6].state)

     7             return true

     8 

     9         if (board.children[i*3].state!=""

    10             && board.children[i*3].state==board.children[i*3+1].state

    11             && board.children[i*3].state==board.children[i*3+2].state)

    12             return true

    13     }

    14 

    15     if (board.children[0].state!=""

    16         && board.children[0].state==board.children[4].state!=""

    17         && board.children[0].state==board.children[8].state!="")

    18         return true

    19 

    20     if (board.children[2].state!=""

    21         && board.children[2].state==board.children[4].state!=""

    22         && board.children[2].state==board.children[6].state!="")

    23         return true

    24 

    25     return false

    26 }

    27 

    28 function restart()

    29 {

    30     // No moves left - start again

    31     for (var i=0; i<9; ++i)

    32         board.children[i].state = ""

    33 }

    34 

    35 function makeMove(pos,player)

    36 {

    37     board.children[pos].state = player

    38     if (winner(board)) {

    39         win(player + " wins")

    40         return true

    41     } else {

    42         return false

    43     }

    44 }

    45 

    46 function computerTurn()

    47 {

    48     var r = Math.random();

    49     if(r < game.difficulty){

    50         smartAI();

    51     }else{

    52         randAI();

    53     }

    54 }

    55 

    56 function smartAI()

    57 {

    58     function boardCopy(a){

    59         var ret = new Object;

    60         ret.children = new Array(9);

    61         for(var i = 0; i<9; i++){

    62             ret.children[i] = new Object;

    63             ret.children[i].state = a.children[i].state;

    64         }

    65         return ret;

    66     }

    67     for(var i=0; i<9; i++){

    68         var simpleBoard = boardCopy(board);

    69         if (board.children[i].state == "") {

    70             simpleBoard.children[i].state = "O";

    71             if(winner(simpleBoard)){

    72                 makeMove(i,"O")

    73                 return

    74             }

    75         }

    76     }

    77     for(var i=0; i<9; i++){

    78         var simpleBoard = boardCopy(board);

    79         if (board.children[i].state == "") {

    80             simpleBoard.children[i].state = "X";

    81             if(winner(simpleBoard)){

    82                 makeMove(i,"O")

    83                 return

    84             }

    85         }

    86     }

    87     function thwart(a,b,c){//If they are at a, try b or c

    88         if (board.children[a].state == "X") {

    89             if (board.children[b].state == "") {

    90                 makeMove(b,"O")

    91                 return true

    92             }else if (board.children[c].state == "") {

    93                 makeMove(c,"O")

    94                 return true

    95             }

    96         }

    97         return false;

    98     }

    99     if(thwart(4,0,2)) return;

   100     if(thwart(0,4,3)) return;

   101     if(thwart(2,4,1)) return;

   102     if(thwart(6,4,7)) return;

   103     if(thwart(8,4,5)) return;

   104     if(thwart(1,4,2)) return;

   105     if(thwart(3,4,0)) return;

   106     if(thwart(5,4,8)) return;

   107     if(thwart(7,4,6)) return;

   108     for(var i =0; i<9; i++){//Backup

   109         if (board.children[i].state == "") {

   110             makeMove(i,"O")

   111             return

   112         }

   113     }

   114     restart();

   115 }

   116 

   117 function randAI()

   118 {

   119     var open = 0;

   120     for (var i=0; i<9; ++i)

   121         if (board.children[i].state == "") {

   122             open += 1;

   123         }

   124     if(open == 0){

   125         restart();

   126         return;

   127     }

   128     var openA = new Array(open);//JS doesn't have lists I can append to (i think)

   129     var acc = 0;

   130     for (var i=0; i<9; ++i)

   131         if (board.children[i].state == "") {

   132             openA[acc] = i;

   133             acc += 1;

   134         }

   135     var choice = openA[Math.floor(Math.random() * open)];

   136     makeMove(choice, "O");

   137 }

   138 

   139 function win(s)

   140 {

   141     msg.text = s

   142     msg.opacity = 1

   143     endtimer.running = true

   144 }

   145