/// <summary>
/// Plays the AI turn
/// </summary>
public int PlayAiTurn(GameObject gameObject)
{
int aiPlayChoice = GameController.playersChoice.Equals("X") ? -1 : 1;
minimaxAlgo.aiPick = aiPlayChoice;
EndTurnPosition bestPositionToEndTurn = minimaxAlgo.GetBestPosition(aiPlayChoice, ConvertBoardToInt(gameObject), 0);
int newBestPositionToPick = bestPositionToEndTurn.position;
//hide ai ui choices from player
foreach (GameObject boardPositions in this.positionArr)
{
foreach (KeyValuePair <string, int> integerStringMapperEntry in boardStringIntegerMapper)
{
if (integerStringMapperEntry.Key == boardPositions.name && integerStringMapperEntry.Value == newBestPositionToPick)
{
if (GameController.playersChoice != boardPositions.transform.GetChild(0).gameObject.name)
{
gameObject.GetComponent <MouseEvents>().renderPositionClicked(boardPositions.transform.GetChild(0).gameObject);
gameObject.GetComponent <ColorControl>().RenderAiOtherChoiceInvisible(boardPositions);
}
else
{
gameObject.GetComponent <MouseEvents>().renderPositionClicked(boardPositions.transform.GetChild(1).gameObject);
gameObject.GetComponent <ColorControl>().RenderAiOtherChoiceInvisible(boardPositions);
}
}
}
}
return(newBestPositionToPick);
}
public EndTurnPosition GetBestPosition(int calculateBestRouteFor, int[] gameBoard, int depth)
{
int isGameOver = IsGameOver(gameBoard);
if (IsBoardFull(gameBoard) && isGameOver == 0) //tie
{
return(new EndTurnPosition(0));
}
else if (isGameOver == 10) //win
{
return(new EndTurnPosition(10 - depth));
}
else if (isGameOver == -10) //lose
{
return(new EndTurnPosition(depth - 10));
}
depth++;
EndTurnPosition levelBestPosition = createEndPositionForLevel(calculateBestRouteFor);
//iterate over this tree level (all possible moves for the current game state)
for (int boardPosition = 0; boardPosition < gameBoard.Length; boardPosition++)
{
//if current board position isnt filled by X or O
if (gameBoard[boardPosition] == 0)
{
gameBoard[boardPosition] = calculateBestRouteFor;
//invert turns between the opponents by multiplying by -1, clone the board (pass by value) so it wont reflect in other decisions on same level
EndTurnPosition newPosition = GetBestPosition(calculateBestRouteFor * -1, (int[])gameBoard.Clone(), depth);
//opponent to the AI - minimizes the result
if (aiPick != calculateBestRouteFor)
{
if (newPosition.score <= levelBestPosition.score)
{
levelBestPosition.position = boardPosition;
levelBestPosition.score = newPosition.score;
}
}
else
{
//AI - maximizes the result
if (newPosition.score >= levelBestPosition.score)
{
levelBestPosition.position = boardPosition;
levelBestPosition.score = newPosition.score;
}
}
//clears the selection that was made so next iteration (which is a node in same tree level) represents the board without it - the next permutation
gameBoard[boardPosition] = 0;
}
}
return(levelBestPosition);
}
public EndTurnPosition GetMelhorPosicao(int calcularMelhorCaminho, int[] gameBoard, int nível)
{
int checkFimDeJogo = CheckFimDeJogo(gameBoard);
if (tabuleiroCompleto(gameBoard) && checkFimDeJogo == 0)
{
return(new EndTurnPosition(0));
}
else if (checkFimDeJogo == 10)
{
return(new EndTurnPosition(10 - nível));
}
else if (checkFimDeJogo == -10)
{
return(new EndTurnPosition(nível - 10));
}
nível++;
EndTurnPosition levelBestPosition = CriarNoFolhaPorNivel(calcularMelhorCaminho);
for (int boardPosition = 0; boardPosition < gameBoard.Length; boardPosition++)
{
if (gameBoard[boardPosition] == 0)
{
gameBoard[boardPosition] = calcularMelhorCaminho;
//inverte o turno entre os jogadores, multiplicando por -1, clonando o tabuleiro (por parâmetro) para não refletir no mesmo nível de decisão do outro jogador
EndTurnPosition newPosition = GetMelhorPosicao(calcularMelhorCaminho * -1, (int[])gameBoard.Clone(), nível);
//oponente - minimizar resultado
if (aiEscolha != calcularMelhorCaminho)
{
if (newPosition.score <= levelBestPosition.score)
{
levelBestPosition.position = boardPosition;
levelBestPosition.score = newPosition.score;
}
}
else
{
//AI - maximizar resultado
if (newPosition.score >= levelBestPosition.score)
{
levelBestPosition.position = boardPosition;
levelBestPosition.score = newPosition.score;
}
}
//limpa a seleção para nao atrapalhar aproxima iteração do oponente (que é no mesmo nível de profundidade)
gameBoard[boardPosition] = 0;
}
}
return(levelBestPosition);
}
private EndTurnPosition CriarNoFolhaPorNivel(int calcularMelhorCaminho)
{
EndTurnPosition levelBestPosition = new EndTurnPosition();
if (aiEscolha != calcularMelhorCaminho)
{
levelBestPosition.score = int.MaxValue;
}
else
{
levelBestPosition.score = int.MinValue;
}
return(levelBestPosition);
}
private EndTurnPosition createEndPositionForLevel(int calculateBestRouteFor)
{
EndTurnPosition levelBestPosition = new EndTurnPosition();
//set default values for AI and opponent so they always pick first position returned to override default
if (aiPick != calculateBestRouteFor)
{
levelBestPosition.score = int.MaxValue;
}
else
{
levelBestPosition.score = int.MinValue;
}
return(levelBestPosition);
}