# ShowBetterPoint.py
""" Shows (in part) what "good design" means when
organizing a class.
"""

from math import sqrt


class Point:
    """
    Attributes:
        x: float, the x-coordinate of a point
        y: float, the y-coordinate of a point
        d: float, the distance of the point to the origin
    """
    def __init__(self,x,y):
        """ Creates a Point object
        PreC: x and y are numbers
        """
        assert type(x)==float or type(x)==int,'x must be a number'
        assert type(y)==float or type(y)==int,'y must be a number'
        x = float(x)
        y = float(y)
        self.x = x
        self.y = y
        self.d = sqrt(x**2+y**2)
    
    def __str__(self):
        """ pretyy prints self.
        """
        return '(%6.3f,%6.3f)     distance = %6.3f'%(self.x,self.y,self.d)
        
    def get_x(self):
        return self.x
    
    def get_y(self):
        return self.y
    
    def get_d(self):
        return self.d
    
    def set_x(self,x):
        assert type(x)==float or type(x)==int,'x must be a number'
        self.x = x
        self.d = sqrt(self.x**2+self.y**2)
    
    def set_y(self,y):
        assert type(y)==float or type(y)==int,'y must be a number'
        self.y = y
        self.d = sqrt(self.x**2+self.y**2)
        
    def Dist(self,P):
        """ Returns the distance from self to P
        PreC: P is a point
        """
        assert isinstance(P,Point),'P must be a Point'
        return sqrt((self.x-P.x)**2+(self.y-P.y)**2)

    def Midpoint(self,P):
        """ Returns the midpoint of the line segment that
        connects self and P.
        PreC: P is a point
        """
        assert isinstance(P,Point),'P must be a Point'
        xm = (self.x+P.x)/2.0
        ym = (self.y+P.y)/2.0
        return Point(xm,ym)