// after we get the best move (button) we return this button to perform click
public Button performMove(int[,] board)
{
AiMove bestMove = getBestMove(board, _aiplayer);
board[bestMove.x, bestMove.y] = _aiplayer;
Button bt = new Button();
bt.Text = "O";
bt.Name = "b" + bestMove.x.ToString() + bestMove.y.ToString();
return(bt);
}
// apply minimax algorithm
private AiMove getBestMove(int[,] board, int player)
{
// base case --> check for end state (win,lose,draw)
int result = iswinner(board);
if (result == _aiplayer)
{
AiMove temp = new AiMove();
temp.SetScore(10);
return(temp);
}
else if (result == _humanplayer)
{
AiMove temp = new AiMove();
temp.SetScore(-10);
return(temp);
}
else if (result == TIE)
{
AiMove temp = new AiMove();
temp.SetScore(0);
return(temp);
}
List <AiMove> moves = new List <AiMove>();
// Do the recursive function calls and construct the moves list (all availabe moves)
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (board[i, j] == NO_VALUE)
{
AiMove move = new AiMove();
move.x = i;
move.y = j;
board[i, j] = player;
if (player == _aiplayer)
{
move.score = getBestMove(board, _humanplayer).score;
}
else
{
move.score = getBestMove(board, _aiplayer).score;
}
moves.Add(move);
board[i, j] = NO_VALUE;
}
}
}
// get the best move for the current player
int bestMove = 0;
if (player == _aiplayer)
{
int bestScore = -100000;
for (int i = 0; i < moves.Count; i++)
{
if (moves[i].score > bestScore)
{
bestScore = moves[i].score;
bestMove = i;
}
}
}
else
{
int bestScore = 100000;
for (int i = 0; i < moves.Count; i++)
{
if (moves[i].score < bestScore)
{
bestScore = moves[i].score;
bestMove = i;
}
}
}
// return the best move
return(moves[bestMove]);
}