/// <summary>
/// Get a list of positions where a pawn has to be flipped, given the position where a new pawn is to be placed.
/// This is basically the effect of a new move on the board.
/// NB: the list does not contain the new pawn.
/// </summary>
/// <param name="pawnPosition">Pawn position</param>
/// <returns>List of positions where to flip pawns</returns>
public List <IntPosition> GetPawnsToFlip(IntPosition pawnPosition)
{
List <IntPosition> pawnsToFlip = new List <IntPosition>();
List <IntPosition> directionsList = GetNeighborsDirections(pawnPosition);
foreach (IntPosition direction in directionsList)
{
List <IntPosition> currentPath = new List <IntPosition>();
Player currentPlayer = playerTurn;
Player oppositePlayer = GetOppositePlayer(currentPlayer);
IntPosition currentPosition = pawnPosition;
currentPosition += direction;
while (IsPositionValid(currentPosition) && gameBoard[currentPosition.Column, currentPosition.Row] == (int)oppositePlayer)
{
currentPath.Add(currentPosition);
currentPosition += direction;
}
if (IsPositionValid(currentPosition) && gameBoard[currentPosition.Column, currentPosition.Row] == (int)currentPlayer)
{
pawnsToFlip.AddRange(currentPath);
}
}
return(pawnsToFlip);
}
/// <summary>
/// Get directions where there's a playable move
/// </summary>
/// <param name="position">Position to check</param>
/// <returns>List of directions</returns>
public List <IntPosition> GetNeighborsDirections(IntPosition position)
{
List <IntPosition> directionsList = new List <IntPosition>();
Player currentPlayer = playerTurn;
Player oppositePlayer = GetOppositePlayer(currentPlayer);
for (int rowDelta = -1; rowDelta <= 1; rowDelta++)
{
for (int columnDelta = -1; columnDelta <= 1; columnDelta++)
{
IntPosition nextPosition = new IntPosition(position.Column + columnDelta, position.Row + rowDelta);
if (IsPositionValid(nextPosition))
{
int slotContentId = gameBoard[nextPosition.Column, nextPosition.Row];
if ((position.Row != nextPosition.Row || position.Column != nextPosition.Column) &&
slotContentId == (int)oppositePlayer &&
IsPositionValid(nextPosition))
{
directionsList.Add(new IntPosition(columnDelta, rowDelta));
}
}
}
}
return(directionsList);
}
/// <summary>
/// Initialize all the data of the game
/// </summary>
/// <param name="gridSize">Size of the board</param>
/// <param name="initialPawnsPosition">Initial position of the pawns (top left corner)</param>
public void InitAll(IntPosition gridSize, IntPosition initialPawnsPosition)
{
playerTurn = Player.Black;
InitPlayersData();
InitGameBoard(gridSize, initialPawnsPosition);
InitTimer();
moveHistory = new List <Tuple <List <IntPosition>, Player> >();
}
/// <summary>
/// Gets the most recent move stored and plays it backwards.
/// </summary>
/// <returns>
/// A tuple containing the coordinates of the affected slots, which
/// player the move belongs to and the coordinates of the pawn that
/// was added to the board (which now has to be removed).
/// </returns>
public Tuple <List <IntPosition>, Player, IntPosition> UndoMove()
{
var lastMove = moveHistory.Last();
List <IntPosition> slotsToUndo = lastMove.Item1;
Player moveAuthor = lastMove.Item2;
IntPosition lastPawnPosition = slotsToUndo.Last();
slotsToUndo.RemoveAt(slotsToUndo.Count - 1);
foreach (var position in slotsToUndo)
{
GameBoard[position.Column, position.Row] = (int)GetOppositePlayer(moveAuthor);
}
GameBoard[lastPawnPosition.Column, lastPawnPosition.Row] = (int)SlotContent.Nothing;
moveHistory.RemoveAt(moveHistory.Count - 1);
return(Tuple.Create(slotsToUndo, moveAuthor, lastPawnPosition));
}
/// <summary>
/// Init. the game board
/// </summary>
/// <param name="gridSize">Size of the board</param>
/// <param name="initialPawnsPosition">Initial position of the pawns (top left corner)</param>
public void InitGameBoard(IntPosition gridSize, IntPosition initialPawnsPosition)
{
gameBoard = new int[gridSize.Column, gridSize.Row];
for (int row = 0; row < Rows; row++)
{
for (int column = 0; column < Columns; column++)
{
gameBoard[column, row] = (int)SlotContent.Nothing;
}
}
gameBoard[initialPawnsPosition.Column, initialPawnsPosition.Row] = (int)SlotContent.White;
gameBoard[initialPawnsPosition.Column + 1, initialPawnsPosition.Row] = (int)SlotContent.Black;
gameBoard[initialPawnsPosition.Column, initialPawnsPosition.Row + 1] = (int)SlotContent.Black;
gameBoard[initialPawnsPosition.Column + 1, initialPawnsPosition.Row + 1] = (int)SlotContent.White;
}
/// <summary>
/// Walk the game board to get all possible moves for the current player.
/// </summary>
/// <returns>
/// A list containing the position of each playable slot.
/// </returns>
public List <IntPosition> GetAllPossibleMoves()
{
List <IntPosition> possibleMovesList = new List <IntPosition>();
for (int rowIndex = 0; rowIndex < Rows; rowIndex++)
{
for (int columnIndex = 0; columnIndex < Columns; columnIndex++)
{
IntPosition currentSlot = new IntPosition(columnIndex, rowIndex);
int slotContentId = gameBoard[currentSlot.Column, currentSlot.Row];
if (slotContentId == (int)playerTurn)
{
List <IntPosition> currentSlotPossibleMovesList = GetNeighborsDirections(currentSlot);
List <IntPosition> movements = new List <IntPosition>();
foreach (IntPosition direction in currentSlotPossibleMovesList)
{
if (IsPossibleMove(currentSlot, direction, movements))
{
IntPosition possibleMove = movements[movements.Count - 1];
possibleMovesList.Add(possibleMove);
}
movements.Clear();
}
}
}
}
if (possibleMovesList.Count == 0)
{
SkipCurrentPlayerTurn();
}
else
{
CurrentPlayerData.HasSkippedLastTurn = false;
}
return(possibleMovesList);
}
/// <summary>
/// Check if there's a valid move in the given direction, if true, the "positions" list is filled with all the positions of the valid move
/// </summary>
/// <param name="pawnPosition">Position to check</param>
/// <param name="direction">Direction to check</param>
/// <param name="positions">Empty list given by the user, filled with severals position if there's a valid move</param>
/// <returns></returns>
public bool IsPossibleMove(IntPosition pawnPosition, IntPosition direction, List <IntPosition> positions)
{
IntPosition currentPosition = pawnPosition;
bool result = false;
Player currentPlayer = playerTurn;
Player oppositePlayer = GetOppositePlayer(currentPlayer);
positions.Add(pawnPosition);
currentPosition += direction;
while (IsPositionValid(currentPosition) && gameBoard[currentPosition.Column, currentPosition.Row] == (int)oppositePlayer)
{
positions.Add(currentPosition);
currentPosition += direction;
}
if (result = IsPositionValid(currentPosition) && (gameBoard[currentPosition.Column, currentPosition.Row] == (int)SlotContent.Nothing))
{
positions.Add(currentPosition);
}
return(result);
}
/// <summary>
/// Overloaded constructor: can define the size of the board and the initial position of the pawns (top left corner)
/// </summary>
/// <param name="gridSize">Size of the board</param>
/// <param name="initialPawnsPosition">Initial position of the pawns (top left corner)</param>
public OthelloLogic(IntPosition gridSize, IntPosition initialPawnsPosition)
{
InitAll(gridSize, initialPawnsPosition);
}
/// <summary>
/// Check if the position is inside the board
/// </summary>
/// <param name="position">Position to check</param>
/// <returns>True if the position is inside board, false otherwise</returns>
public bool IsPositionValid(IntPosition position)
{
return(position.Row >= 0 && position.Row < Rows && position.Column >= 0 && position.Column < Columns);
}
