//Find out random play position
private PlayPosition findRandomPlayPosition()
{
PlayPosition posBest = null;
PlayPosition[] freepos = new PlayPosition[9];
int nosFree = 0;
//Find all empty play positions
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (_arrBoard[i][j].Value == ' ')
{
freepos[nosFree] = new PlayPosition();
freepos[nosFree].X = i;
freepos[nosFree].Y = j;
nosFree++;
}
}
}
if (nosFree > 0)
{
Random rnd = new Random();
int temp = rnd.Next(0, nosFree - 1);
posBest = freepos[temp];
}
return(posBest);
}
//Find next move for a play char X or O
private PlayPosition FindNextMove(char playChar)
{
BoardCell cell = null;
PlayPosition posBest = null;
do
{
for (int i = 0; i < 3; i++)
{
cell = findEmptyCell(_arrBoard[0][i], _arrBoard[1][i], _arrBoard[2][i], playChar);//|1 |2 |3
if (cell != null)
{
posBest = cell.CellPos;
break;
}
}
if (posBest != null)
{
break;
}
cell = findEmptyCell(_arrBoard[0][0], _arrBoard[1][1], _arrBoard[2][2], playChar);//\
if (cell != null)
{
posBest = cell.CellPos;
break;
}
cell = findEmptyCell(_arrBoard[0][2], _arrBoard[1][1], _arrBoard[2][0], playChar);// /
if (cell != null)
{
posBest = cell.CellPos;
break;
}
for (int i = 0; i < 3; i++)
{
cell = findEmptyCell(_arrBoard[i][0], _arrBoard[i][1], _arrBoard[i][2], playChar);//--1 --2 --3
if (cell != null)
{
posBest = cell.CellPos;
break;
}
}
} while (false);
return(posBest);
}
//Play a position
public void Play(PlayPosition playPos)
{
_nosMoves++;
_lastTurn = _playTurn;
if (_playTurn == PlayerNumber.FirstPlayer)//First Player turn
{
_gameBoard.SetAt(playPos.X, playPos.Y, (char)PlayChars.First);
_playTurn = PlayerNumber.SecondPlayer;
}
else if (_playTurn == PlayerNumber.SecondPlayer)//Second player turn
{
_gameBoard.SetAt(playPos.X, playPos.Y, (char)PlayChars.Second);
_playTurn = PlayerNumber.FirstPlayer;
}
//Check game is over only after 5 play moves.
if (_nosMoves >= 5)
{
if (_gameBoard.IsGameOver())
{
_gameOver = true;
}
}
//If game is over then update WhoWon and score
if (_nosMoves == 9 || _gameOver)
{
_gameOver = true;
if (_gameBoard.whoWon == (char)PlayChars.First)
{
_wonPlayer = PlayerNumber.FirstPlayer;
}
else if (_gameBoard.whoWon == (char)PlayChars.Second)
{
_wonPlayer = PlayerNumber.SecondPlayer;
}
if (_wonPlayer > 0)
{
_players[((int)_wonPlayer) - 1].Score++;
}
}
}
//Find execute computer play
public GameResult DoComputerPlay()
{
GameResult gameRslt = null;
//At end if next player is computer type then execute next play too.
if (_objGame.NextPlayer == PlayerNumber.SecondPlayer && _objGame.Players[1].Type == PlayerType.Computer && !_objGame.gameOver)//if 2nd player is a computer
{
//Find our next best play
PlayPosition nextPlay = ((ComputerPlayer)_objGame.Players[1]).GetNextMove(_objGame.GameBoard);
//Play that move
gameRslt = this.UserPlay(nextPlay);
}
else
{
//Otherwise just return current gameboard
gameRslt = new GameResult();
gameRslt.GameBoard = _objGame.GameBoard;
}
return(gameRslt);
}
//Execute a user play
public GameResult UserPlay(PlayPosition playPos)
{
GameResult gameRslt = new GameResult();
//Play
_objGame.Play(playPos);
//Prepare play result
gameRslt.LastPlayedPosition = playPos;
gameRslt.GameBoard = _objGame.GameBoard;
gameRslt.GameOver = _objGame.gameOver;
gameRslt.Players = _objGame.Players;
//Check game over flag
if (_objGame.gameOver)
{
gameRslt.WhoWon = _objGame.wonPlayer;
gameRslt.GameOver = _objGame.gameOver;
}
return(gameRslt);
}
//Get next play position for computer type player
public PlayPosition getNextBestPlay()
{
PlayPosition posBest = null;
posBest = FindNextMove((char)PlayChars.Second);//Check any Winning move
if (posBest != null)
{
return(posBest);
}
posBest = FindNextMove((char)PlayChars.First);//Check any defending move
if (posBest != null)
{
return(posBest);
}
posBest = findRandomPlayPosition();//Find a random play
return(posBest);
}
//Find next best move of computer type player
public PlayPosition GetNextMove(IGameBoard board)
{
PlayPosition pos = board.getNextBestPlay();
return(pos);
}
