QUIZ_8

# Written by *** for COMP9021
#
# Defines two classes, Point and Triangle.
#
# An object of class Point is created by passing exactly
# 2 integers as arguments to __init__().
# You can assume that nothing but integers will indeed be
# passed as arguments to __init__(), but not that exactly
# 2 arguments will be provided; when that is not the case,
# a PointError error is raised.
# The point class implements the __str__() and __repr__()
# special methods.
#
# An object of class Triangle is created by passing exactly
# 3 points as keyword only arguments to __init__().
# You can assume that exactly three points will indeed be
# passed as arguments to __init__().
# The three points should not be collinear for the triangle
# to be created; otherwise a TriangleError error is raised.
# A triangle object can be modified by changing one two or three
# points thanks to the method change_point_or_points(),
# all of whose arguments are keyword only.
# At any stage, the object maintains correct values
# for perimeter and area.


from math import sqrt


# INSERT YOUR CODE HERE
class PointError(Exception):
    pass


class TriangleError(Exception):
    pass


class Point:
    def __init__(self, *args):
        if len(args) != 2:
            raise PointError("Need two coordinates, point not created.")
        if not isinstance(args[0], int) or not isinstance(args[1], int):
            raise PointError("Coordinates must be integers.")
        self.x = args[0]
        self.y = args[1]

    def __repr__(self):
        return f"Point({self.x}, {self.y})"

    def __str__(self):
        return f"Point of x-coordinate {self.x} and y-coordinate {self.y}"


class Triangle:
    def __init__(self, **kwargs):
        self.p1 = kwargs['point_1']
        self.p2 = kwargs['point_2']
        self.p3 = kwargs['point_3']
        self.check_valid()

    def check_valid(self):
        if self.is_collinear():
            raise TriangleError("Incorrect input, triangle not created.")

    def is_collinear(self):
        return (self.p2.y - self.p1.y) * (self.p3.x - self.p1.x) == (self.p3.y - self.p1.y) * (self.p2.x - self.p1.x)

    @property
    def perimeter(self):
        side1 = self.calculate_distance(self.p1, self.p2)
        side2 = self.calculate_distance(self.p2, self.p3)
        side3 = self.calculate_distance(self.p3, self.p1)
        return side1 + side2 + side3

    @property
    def area(self):
        a = self.calculate_distance(self.p1, self.p2)
        b = self.calculate_distance(self.p2, self.p3)
        c = self.calculate_distance(self.p3, self.p1)
        p = (a + b + c) / 2
        return sqrt(p * (p - a) * (p - b) * (p - c))

    def calculate_distance(self, p1, p2):
        return sqrt(((p2.x - p1.x) ** 2 + (p2.y - p1.y) ** 2))

    def change_point_or_points(self, **kwargs):
        flag=0
        tmp_p1,tmp_p2,tmp_p3=self.p1,self.p2,self.p3
        for key, value in kwargs.items():
            if key == 'point_1':
                tmp_p1 = self.p1
                self.p1 = value
            elif key == 'point_2':
                tmp_p2 = self.p2
                self.p2 = value
            elif key == 'point_3':
                tmp_p3 = self.p3
                self.p3 = value
        if self.is_collinear():
            flag = 1
            self.p1 = tmp_p1
            self.p2 = tmp_p2
            self.p3 = tmp_p3
        if flag==1:
            print("Incorrect input, triangle not modified.")