"""Maths."""

from decimal import Decimal
import math


def find_multiple_of_n_nearest_x(n, x):
    """Find multiple of n nearest x."""
    if n == 0:
        return None

    n = Decimal(int(n))
    x = Decimal(str(x))

    return int(n * round(x / n))


def percent_change(n1, n2):
    """Calculate the percent change from n1 to n2."""
    n1 = Decimal(n1)
    n2 = Decimal(n2)

    if n1 == 0:
        return math.inf
    else:
        s = ((n2 - n1) / n1.copy_abs())

    return s * 100


def euclidean_distance_2d(x1, y1, x2, y2):
    """Calculate the distance between two points in 2d space.

    Args:
        x1 (float): x coordinate of point 1.
        y1 (float): y coordinate of point 1.
        x2 (float): x coordinate of point 2.
        y2 (float): y coordinate of point 2.
    Returns:
        float: Distance between points 1 and 2.
    """
    return math.sqrt(math.pow(x1 - x2, 2) + math.pow(y1 - y2, 2))