class FunctionResult:
    def __init__(self, y, x):
        self.x = x
        self.y = y


class QuadroInterpolation:
    def __init__(self, func, x_1, delta, eps, eps_1):
        self.func = func
        self.x_1 = x_1
        self.delta = delta
        self.eps = eps
        self.eps_1 = eps_1

    def compute(self):
        self.x_2 = self.x_1 + self.delta
        self.left_border = FunctionResult(self.func(self.x_1), self.x_1)
        self.right_border = FunctionResult(self.func(self.x_2), self.x_2)
        self.x_3 = self.x_1 + 2 * self.delta if self.right_border.y < self.left_border.y else self.x_1 - self.delta
        self.center = FunctionResult(self.func(self.x_3), self.x_3)
        self.compute_2()

    def compute_2(self):
        temp = sorted((self.left_border, self.right_border, self.center), key=lambda v: v.y)[0]
        F_MIN = getattr(temp, 'y')
        x_min = temp.x
        x_hat = self.interpolation_polynomial()
        if x_hat:
            print(abs((F_MIN - self.func(x_hat)) / self.func(x_hat)) < self.eps and abs(
                (x_min - x_hat) / x_hat) < self.eps_1)
            if abs((F_MIN - self.func(x_hat)) / self.func(x_hat)) < self.eps and abs(
                    (x_min - x_hat) / x_hat) < self.eps_1:
                self.res = x_hat
                return
            else:
                if self.x_1 <= x_hat <= self.x_3:
                    self.x_1, self.x_2, self.x_3 = sorted([self.x_1, self.x_2, self.x_3, x_hat, x_min])[:3]
                    self.left_border = FunctionResult(self.func(self.x_1), self.x_1)
                    self.right_border = FunctionResult(self.func(self.x_2), self.x_2)
                    self.center = FunctionResult(self.func(self.x_3), self.x_3)
                    self.compute_2()
                else:
                    self.x_1 = x_hat
                    self.compute()
        else:
            self.res = self.func(x_hat)

    def square_diff(self, x, y):
        return x ** 2 - y ** 2

    def interpolation_polynomial(self):
        try:
            return 0.5 * (
                    (
                            self.square_diff(self.x_2, self.x_3)
                            * self.left_border.y + self.square_diff(self.x_3, self.x_1)
                            * self.right_border.y + self.square_diff(self.x_1, self.x_2)
                            * self.center.y
                    )
                    /
                    (
                            (self.x_2 - self.x_3) * self.left_border.y
                            + (self.x_3 - self.x_1) * self.right_border.y
                            + (self.x_1 - self.x_2) * self.center.y
                    )
            )
        except ZeroDivisionError:
            return 0


def func(x):
    return x**2


a = QuadroInterpolation(func, 2, 1, 0.003, 0.03)
a.compute()

print(a.res)