nearby.cs

public bool Nearby(Point enemyLoc, Point playerLoc, int distance, Direction direction)
{
    //it helps human understanding and debugging to do all your calculations seperately, instead of one massive hard to read switch/if statements
    bool isNearby = false;

    //get the deltas
    int deltaX = playerLoc.X - enemyLoc.X,
        deltaY = playerLoc.Y - enemyLoc.Y;

    //determine direction, you may need to flip which one is negative and positive for it to work
    int xDir = 0, yDir = 0;
    if (deltaX > 0) {
        xDir = 1;
    } else (deltaX < 0) {
        xDir = -1;
    }

    if (deltaY > 0) {
        yDir = 1;
    } else (deltaY < 0) {
        yDir = -1;
    }

    //get actual distance
    int distX = Math.Abs(deltaX),
        distY = Math.Abs(deltaY);

    switch (direction)
    {
        //now the switch statement is alot cleaner, and easier to read for a human
        case Direction.Up:
            if (distY < distance && xDir == 0 && yDir > 0)
                isNearby = true;
            break;
        case Direction.Down:
            if (distY < distance && xDir == 0 && yDir < 0)
                isNearby = true;
            break;
        case Direction.Left:
            if (distX < distance && yDir == 0 && xDir > 0)
                isNearby = true;
            break;
        case Direction.Right:
            if (distX < distance && yDir == 0 && xDir < 0)
                isNearby = true;
            break;
    }
    return isNearby;
}