# point.py
# Walker M. White (wmw2)
# October 15, 2015
"""Module with a simple Point3 class.

This module has a simpler version of the Point class.  The primary purpose
of this module is to show off the built-in methods __str__ and __repr___"""
import math

class Point3(object):
    """Instance is a point in 3D space
    
    INSTANCE ATTRIBUTES
        x: x coordinate [float]
        y: y coordinate [float]
        z: z coordinate [float]
    """

    # INITIALIZER
    def __init__(self,x=0.0,y=0.0,z=0.0): 
        """Initializer:  makes a new Point3
        
        Parameter x: the x-coordinate (default is 0.0)
        Precondition: x is a float (or optional)
        
        Parameter y: the y-coordinate (default is 0.0)
        Precondition: y is a float (or optional)
        
        Parameter z: the z-coordinate (default is 0.0)
        Precondition: z is a float (or optional)
        """
        self.x = x # x is parameter, self.x is field  
        self.y = y # y is parameter, self.y is field  
        self.z = z # z is parameter, self.z is field  
    
    def __str__(self):
        """Returns: this Point as a string '(x, y, z)'"""
        return '('+str(self.x)+', '+str(self.y)+', '+str(self.z)+')'

    def __repr__(self):
        """Returns: unambiguous representation of Point3"""
        return str(self.__class__)+str(self)
    
    def distanceTo(self,other):
        """Returns: Distance from self to other
        
        Parameter other: the point to measure to
        Precondition: other is a Point3"""
        assert type(other) == Point, `other`+' is not a Point3'
        dx = (self.x-other.x)*(self.x-other.x)
        dy = (self.y-other.y)*(self.y-other.y)
        dz = (self.z-other.z)*(self.z-other.z)
        return math.sqrt(dx+dy+dz)