public static bool CanBeBlocked(this Figure enemy, Figure theKing, IList <Figure> figures)
{
var directHitters = new[] { FigureType.Knight, FigureType.Pawn };
if (directHitters.Contains(enemy.Type))
{
return(false);
}
var moveX = Math.Sign(theKing.Cell.X - enemy.Cell.X);
var moveY = Math.Sign(theKing.Cell.Y - enemy.Cell.Y);
var nextPos = new Pos(enemy.Cell.Y + moveY, enemy.Cell.X + moveX);
var kingAllies = figures.Where(f => f.IsAllyOf(theKing)).ToArray();
while (!nextPos.Equals(theKing.Cell))
{
if (kingAllies.Any(a => a.CanReach(nextPos, figures)))
{
return(true);
}
nextPos = new Pos(nextPos.Y + moveY, nextPos.X + moveX);
}
return(false);
}
public static bool CanHit(this Figure figure, Pos cell, IList <Figure> board)
{
if (figure.Type == FigureType.Pawn)
{
var enemyInCell = board.SingleOrDefault(f => f.Cell.Equals(cell));
if (enemyInCell != null &&
enemyInCell.Type == FigureType.Pawn &&
enemyInCell.PrevCell != null &&
enemyInCell.PrevCell.Value.Y - cell.Y == 2 &&
Math.Abs(cell.X - figure.Cell.X) == 1)
{
return(true);
}
if (figure.Owner == 1) // if the figure is black
{
return(figure.Cell.Equals(new Pos(cell.Y - 1, cell.X - 1)) ||
figure.Cell.Equals(new Pos(cell.Y - 1, cell.X + 1)));
}
else // if the figure is white
{
return(figure.Cell.Equals(new Pos(cell.Y + 1, cell.X - 1)) ||
figure.Cell.Equals(new Pos(cell.Y + 1, cell.X + 1)));
}
}
if (figure.Type == FigureType.King)
{
var hitPositions = new[]
{
new Pos(cell.Y + 1, cell.X + 1),
new Pos(cell.Y + 1, cell.X),
new Pos(cell.Y + 1, cell.X - 1),
new Pos(cell.Y - 1, cell.X + 1),
new Pos(cell.Y - 1, cell.X),
new Pos(cell.Y - 1, cell.X - 1),
new Pos(cell.Y, cell.X + 1),
new Pos(cell.Y, cell.X - 1)
};
return(hitPositions.Any(x => figure.Cell.Equals(x)));
}
if (figure.Type == FigureType.Knight)
{
var hitPositions = new[]
{
new Pos(cell.Y - 2, cell.X + 1),
new Pos(cell.Y - 2, cell.X - 1),
new Pos(cell.Y + 2, cell.X + 1),
new Pos(cell.Y + 2, cell.X - 1),
new Pos(cell.Y + 1, cell.X - 2),
new Pos(cell.Y - 1, cell.X - 2),
new Pos(cell.Y + 1, cell.X + 2),
new Pos(cell.Y - 1, cell.X + 2),
};
return(hitPositions.Any(x => figure.Cell.Equals(x)));
}
var occupied = board.Select(x => x.Cell).ToArray();
if (figure.Type == FigureType.Bishop)
{
if (figure.Cell.Y == figure.Cell.X - (cell.X - cell.Y) ||
figure.Cell.Y + figure.Cell.X == cell.X + cell.Y)
{
var moveX = Math.Sign(cell.X - figure.Cell.X);
var moveY = Math.Sign(cell.Y - figure.Cell.Y);
var nextPos = new Pos(figure.Cell.Y + moveY, figure.Cell.X + moveX);
while (!nextPos.Equals(cell))
{
if (occupied.Contains(nextPos))
{
return(false);
}
nextPos = new Pos(nextPos.Y + moveY, nextPos.X + moveX);
}
return(true);
}
return(false);
}
if (figure.Type == FigureType.Rook)
{
if (figure.Cell.X == cell.X || figure.Cell.Y == cell.Y)
{
var moveX = Math.Sign(cell.X - figure.Cell.X);
var moveY = Math.Sign(cell.Y - figure.Cell.Y);
var nextPos = new Pos(figure.Cell.Y + moveY, figure.Cell.X + moveX);
while (!nextPos.Equals(cell))
{
if (occupied.Contains(nextPos))
{
return(false);
}
nextPos = new Pos(nextPos.Y + moveY, nextPos.X + moveX);
}
return(true);
}
return(false);
}
if (figure.Type == FigureType.Queen)
{
if (figure.Cell.X == cell.X ||
figure.Cell.Y == cell.Y ||
figure.Cell.Y == figure.Cell.X - (cell.X - cell.Y) ||
figure.Cell.Y + figure.Cell.X == cell.X + cell.Y)
{
var moveX = Math.Sign(cell.X - figure.Cell.X);
var moveY = Math.Sign(cell.Y - figure.Cell.Y);
var nextPos = new Pos(figure.Cell.Y + moveY, figure.Cell.X + moveX);
while (!nextPos.Equals(cell))
{
if (occupied.Contains(nextPos))
{
return(false);
}
nextPos = new Pos(nextPos.Y + moveY, nextPos.X + moveX);
}
return(true);
}
return(false);
}
return(true);
}