/// <summary>
/// Determining whether a move from the current coordinate in a specific direction is possible.
/// </summary>
/// <param name="coordinates">Current coordinates to check.</param>
/// <param name="direction">Current direction from coordinates to check.</param>
/// <returns>Whether the marker position is a possible move.</returns>
private bool PossibleMove(Coordinates coordinates, ReversiPlayer player, Direction direction)
{
bool valid = false;
int x = coordinates.X;
int y = coordinates.Y;
switch (direction)
{
case Direction.Up:
y--;
while (y > 0 && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
y--;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.Down:
y++;
while (y < _markers.GetUpperBound(1) && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
y++;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.Left:
x--;
while (x > 0 && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
x--;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.Right:
x++;
while (x < _markers.GetUpperBound(0) && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
x++;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.DiagonalRightUp:
x++;
y--;
while ((x < _markers.GetUpperBound(0) && y > 0) && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
x++;
y--;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.DiagonalRightDown:
x++;
y++;
while ((x < _markers.GetUpperBound(0) && y < _markers.GetUpperBound(1)) && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
x++;
y++;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.DiagonalLeftUp:
x--;
y--;
while ((x > 0 && y > 0) && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
x--;
y--;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
case Direction.DiagonalLeftDown:
x--;
y++;
while ((x > 0 && y < _markers.GetUpperBound(1) && y > 0) && !valid)
{
if (_markers[x, y] == ReversiPlayer.None) { goto FoundEmpty; }
x--;
y++;
if (_markers[x, y] == _currentPlayer) { valid = true; }
}
break;
}
if (valid)
{
_targetCoordinates = new Coordinates(x, y);
}
FoundEmpty:
return valid;
}
/// <summary>
/// Checks if current tile is a valid move for the current player.
/// </summary>
/// <param name="coordinates">Coordinates that indicate the current tile.</param>
/// <returns>Valid move or not.</returns>
private bool IsValidLocation(Coordinates coordinates)
{
if ((coordinates.X >= 0 && coordinates.X <= _markers.GetUpperBound(0)) &&
(coordinates.Y >= 0 && coordinates.Y <= _markers.GetUpperBound(1)))
{
// Check if marker already exists
if (_markers[coordinates.X, coordinates.Y] != ReversiPlayer.None)
{
return false;
}
bool validLocation = false;
ReversiPlayer opponent = _currentPlayer ^ (ReversiPlayer)3;
// Check 3 spots to the right of tile
if (coordinates.X < _markers.GetUpperBound(0))
{
if (coordinates.Y > 0 && _markers[coordinates.X + 1, coordinates.Y - 1] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalRightUp))
{
validLocation = true;
}
}
if (coordinates.Y < _markers.GetUpperBound(1) && _markers[coordinates.X + 1, coordinates.Y + 1] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalRightDown))
{
validLocation = true;
}
}
if (_markers[coordinates.X + 1, coordinates.Y] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.Right))
{
validLocation = true;
}
}
if (validLocation)
{
goto FoundValidMove;
}
}
// Check 3 spots to the left of tile
if (coordinates.X > 0)
{
if (coordinates.Y > 0 && _markers[coordinates.X - 1, coordinates.Y - 1] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalLeftUp))
{
validLocation = true;
}
}
if (coordinates.Y < _markers.GetUpperBound(1) && _markers[coordinates.X - 1, coordinates.Y + 1] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalLeftDown))
{
validLocation = true;
}
}
if (_markers[coordinates.X - 1, coordinates.Y] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.Left))
{
validLocation = true;
}
}
if (validLocation)
{
goto FoundValidMove;
}
}
// Check 1 spot below the tile
if (coordinates.Y < _markers.GetUpperBound(1))
{
if (_markers[coordinates.X, coordinates.Y + 1] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.Down))
{
validLocation = true;
}
}
if (validLocation)
{
goto FoundValidMove;
}
}
// Check 1 spot above the tile
if (coordinates.Y > 0)
{
if (_markers[coordinates.X, coordinates.Y - 1] == opponent)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.Up))
{
validLocation = true;
}
}
}
FoundValidMove:
return validLocation;
}
return false;
}
/// <summary>
/// Flip opponent markers from current move at specified coordinates.
/// </summary>
/// <param name="coordinates">Coordinates of the newly placed marker.</param>
private void FlipOpponentMarkers(Coordinates coordinates)
{
if (PossibleMove(coordinates, _currentPlayer, Direction.Up))
{
for (int i = coordinates.Y; i > _targetCoordinates.Y; i--)
{
_markers[coordinates.X, i] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.Down))
{
for (int i = coordinates.Y; i < _targetCoordinates.Y; i++)
{
_markers[coordinates.X, i] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.Left))
{
for (int i = coordinates.X; i > _targetCoordinates.X; i--)
{
_markers[i, coordinates.Y] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.Right))
{
for (int i = coordinates.X; i < _targetCoordinates.X; i++)
{
_markers[i, coordinates.Y] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalRightUp))
{
int j = coordinates.Y;
for (int i = coordinates.X; i < _targetCoordinates.X; i++, j--)
{
_markers[i, j] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalRightDown))
{
int j = coordinates.Y;
for (int i = coordinates.X; i < _targetCoordinates.X; i++, j++)
{
_markers[i, j] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalLeftUp))
{
int j = coordinates.Y;
for (int i = coordinates.X; i > _targetCoordinates.X; i--, j--)
{
_markers[i, j] = _currentPlayer;
}
}
if (PossibleMove(coordinates, _currentPlayer, Direction.DiagonalLeftDown))
{
int j = coordinates.Y;
for (int i = coordinates.X; i > _targetCoordinates.X; i--, j++)
{
_markers[i, j] = _currentPlayer;
}
}
_currentPlayer ^= (ReversiPlayer)3;
this.Invalidate();
}
/// <summary>
/// For clicking on the game board and adding a marker to a location on the grid.
/// </summary>
/// <param name="e">MouseEventArgs.</param>
protected override void OnMouseUp(MouseEventArgs e)
{
base.OnMouseUp(e);
// Check release boundaries
Coordinates coordinates = new Coordinates(e.X / _tileSize, e.Y / _tileSize);
if (IsValidLocation(coordinates))
{
_markers[coordinates.X, coordinates.Y] = _currentPlayer;
FlipOpponentMarkers(coordinates);
_faintCollection.Clear();
UpdateMarkerCount();
if (GameFinished)
{
GameOver();
}
}
}
/// <summary>
/// Calculates move validity and shows faint marker indicator for valid tiles
/// to place markers on.
/// </summary>
/// <param name="e">MouseEventArgs.</param>
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (e.Button == MouseButtons.None)
{
Coordinates coordinates = new Coordinates(e.X / _tileSize, e.Y / _tileSize);
if (!_lastCoordinates.Equals(coordinates))
{
if (IsValidLocation(coordinates))
{
_faintCollection.Add(new Marker(_currentPlayer, coordinates));
if (_faintCollection.Count > 1)
{
_faintCollection.RemoveAt(0);
}
}
_lastCoordinates = coordinates;
}
}
}
// Constructor
public Marker(ReversiPlayer player, Coordinates location)
{
this.Player = player;
this.TileCoordinates = location;
}
