Reversi AI algorithm

[emilio]

hi. i'm trying to write a reversi game with a smart computer player.
i want to use an alpha beta pruning minimax algorithm.

i wrote the code but the computer is not smart.
can somebody help me with my code ?

public int[] Play(String s,GameBoard gb,Color c) 
    {  
      int alpha = Integer.MAX_VALUE;  
      int beta = -alpha;  
 
        // returns the computers best move
      return BestMove (gb,true,maxDepth, alpha, beta, c);
      
    }
    
    private int[] BestMove(GameBoard gb ,boolean isMax, int depth ,int alpha , int beta,  Color c)
    {
       int score = -maxScore;   
       
      // the opponent takes the best score
       if (!isMax)
           score = -score;
       
      // this is the array i will return as best move
       int[] move = new int[3];
       
      // all possible moves
       List<int[]> AllMoves = gb.CalcAllMoves(c);
       
      // check all the moves
       for (int[] tmpMove : AllMoves)
       {
           int moveScore = 0;

           // clone the game board and play the temp move
           GameBoard tmpBoard = gb.CloneBoard();
           tmpBoard.PlayMove(tmpMove, tmpBoard.CheckMove(tmpMove, c), c == Color.black ? true : false);
           
         // if the game is over, evaluate the score
           if (tmpBoard.isEnd())
               moveScore = tmpBoard.scoreEval(c) - tmpBoard.scoreEval(c == Color.black ? Color.white : Color.black );
           
        // perform recursive call
           else if (depth > 0)
           {
               moveScore = BestMove (tmpBoard, !isMax, depth -1,alpha, beta, c)[2];
               
               if (isMax && tmpMove[2] > beta)
		   beta = tmpMove[2];
							
               if (!isMax && tmpMove[2] < alpha)
		   alpha = tmpMove[2];   
           }
           
        // if we over the depth evaluate the board
           else
               moveScore = tmpBoard.bestEval(c);
           
           if (isMax && tmpMove[2] > alpha)
	   {
	     tmpMove[2] = alpha;
	        return tmpMove;
	   }
						
           if (!isMax && tmpMove[2] < beta)
	   {
	     tmpMove[2] = beta;
		return tmpMove;
	   }
           
        // take the move which got the highest score
           if (isMax ? moveScore > score : moveScore < score)
           {
               score = moveScore;
               move = tmpMove;
               move[2] = moveScore;
           }
           
       }
       
       return move;
    }