/// <summary>
/// Evaluates the board, looking for the best position for the AI Actor
/// </summary>
/// <param name="playfield">The board in question</param>
/// <param name="IsOpponentsMove">Is the player playing right now the AI actor or the opponent, Defaults to it being the AI actor</param>
/// <param name="depth">remaining depth to evaluate. Defaults to 0</param>
/// <param name="alphaValue">alpha of the current best move. Needed for A/B pruning. Defaults to the AI actor is player 0</param>
/// <returns>returns the evaluation of the board position for player 0</returns>
private float EvaluatePositionNoOptimizations(Playfield playfield, bool IsOpponentsMove = false, int depth = 0)
{
//check to see if we've reached the bottom of the evaluation tree. If we have evaluate that position
if (depth < 1)
{
return(Evaluate(playfield.GetBoard()));
}
float LocalAlpha; //LocalAlpha is the value "best" move found so far for the players whose move it is, defaults to the worst value.
float CurrentMoveAlpha = 0;
if (playfield.WhoseTurnIsIt() == 0)
{
LocalAlpha = float.MinValue;
}
else
{
LocalAlpha = float.MaxValue;
}
bool[] IsALegalMove = playfield.LegalMoves();
for (int i = 0; i < playfield.Width; i++)
{
if (IsALegalMove[i])
{
if (playfield.MakeMoveNoErrorChecking(i)) //returns true if the game is over (draw or win)
{
if (playfield.Status == PlayStatus.Win)
{
playfield.UndoMove();
if (playfield.WhoseTurnIsIt() == 0)
{
return(float.MaxValue);
}
else
{
return(float.MinValue);
}
}
else if (playfield.Status == PlayStatus.Draw)
{
CurrentMoveAlpha = 0; //draws return 0
}
}
else
{
CurrentMoveAlpha = EvaluatePositionNoOptimizations(playfield, true, depth - 1);
}
playfield.UndoMove(); //reset the board to its original condition
if ((playfield.WhoseTurnIsIt() == 0 && CurrentMoveAlpha > LocalAlpha) || (playfield.WhoseTurnIsIt() != 0 && CurrentMoveAlpha < LocalAlpha))
{
LocalAlpha = CurrentMoveAlpha;
}
}
}
return(LocalAlpha);
}
