public void AddSnakePiece(SnakePiece piece)
{
snake.Add(piece);
matrix[piece.Row, piece.Column] = piece;
}
/// <summary>
/// Attempts to move the snake head to the desired direction
/// </summary>
/// <param name="direction"></param>
/// <returns>Movement result</returns>
public MovementResult TryMove(SnakeMovement direction)
{
//get a reference to the head
SnakePiece head = snake[0];
RowColumn newHeadLocation = new RowColumn();
//check if the movement is valid, depending on
//1. out of bounds check
//2. new place to move is not already occupied by a snake piece
switch (direction)
{
case SnakeMovement.Left:
if (head.Column == 0 ||
(matrix[head.Row, head.Column - 1] != null && matrix[head.Row, head.Column - 1] is SnakePiece))
{
return(MovementResult.GameOver);
}
else
{
newHeadLocation = new RowColumn(head.Row, head.Column - 1);
}
break;
case SnakeMovement.Right:
if (head.Column == Constants.Columns - 1 ||
(matrix[head.Row, head.Column + 1] != null && matrix[head.Row, head.Column + 1] is SnakePiece))
{
return(MovementResult.GameOver);
}
else
{
newHeadLocation = new RowColumn(head.Row, head.Column + 1);
}
break;
case SnakeMovement.Top:
if (head.Row == 0 ||
(matrix[head.Row - 1, head.Column] != null && matrix[head.Row - 1, head.Column] is SnakePiece))
{
return(MovementResult.GameOver);
}
else
{
newHeadLocation = new RowColumn(head.Row - 1, head.Column);
}
break;
case SnakeMovement.Bottom:
if (head.Row == Constants.Rows - 1 ||
(matrix[head.Row + 1, head.Column] != null && matrix[head.Row + 1, head.Column] is SnakePiece))
{
return(MovementResult.GameOver);
}
else
{
newHeadLocation = new RowColumn(head.Row + 1, head.Column);
}
break;
}
//if we have reached here, the move is allowed. We also check if there is a fruit piece in the new space
MovementResult result = MovementResult.MoveAllowed;
if (this[newHeadLocation.Row, newHeadLocation.Column] is FruitPiece)
{
result = MovementResult.FruitEaten;
}
//modify the Piece properties to reflect the new location
var pieceLocation = head.RowColumn;
MovePiece(head, newHeadLocation.Row, newHeadLocation.Column);
//for all the rest snake pieces, move them
//easy to do, the [i] piece is moved to the location of the [i-1] one
for (int i = 1; i < snake.Count; i++)
{
//cache the item to be moved
var cache = snake[i].RowColumn;
//move it to the i-1 location
MovePiece(snake[i], pieceLocation.Row, pieceLocation.Column);
//cache the i location
pieceLocation = cache;
}
//pieceLocation now has the previous location of the last snake item
//no fruit eaten, so nullify it
if (result == MovementResult.MoveAllowed)
{
this[pieceLocation.Row, pieceLocation.Column] = null;
}
//fruit eaten, so add another piece to the snake
else if (result == MovementResult.FruitEaten)
{
this.AddSnakePiece(new SnakePiece(pieceLocation.Row, pieceLocation.Column, Colors.Navy));
FruitExists = false;
TimeFruitWasCreatedOrEaten = DateTime.Now;
}
return(result);
}
/// <summary>
/// Set the relevant properties of the piece object
/// </summary>
/// <param name="piece"></param>
/// <param name="newRow"></param>
/// <param name="newColumn"></param>
private void MovePiece(SnakePiece piece, int newRow, int newColumn)
{
piece.Row = newRow;
piece.Column = newColumn;
matrix[newRow, newColumn] = piece;
}