import os
import re
from copy import deepcopy
from functools import reduce
from itertools import permutations
from math import gcd

inputfile = os.path.join(os.path.dirname(__file__), "input/day12_input")


def get_moons():
    with open(inputfile) as fp:
        return [[int(m[1]), int(m[2]), int(m[3])]
                for m in
                re.finditer(r'x=(-?\d+).*y=(-?\d+).*z=(-?\d+)', fp.read())]


def test_day12a():
    moons = [(m, [0, 0, 0]) for m in get_moons()]
    e = 0
    for _ in range(1000):
        for me, other in permutations(moons, 2):
            v = me[1]
            pa = me[0]
            pb = other[0]
            v[0] += -1 if pa[0] > pb[0] else 1 if pa[0] < pb[0] else 0
            v[1] += -1 if pa[1] > pb[1] else 1 if pa[1] < pb[1] else 0
            v[2] += -1 if pa[2] > pb[2] else 1 if pa[2] < pb[2] else 0
        for moon in moons:
            moon[0][0] += moon[1][0]
            moon[0][1] += moon[1][1]
            moon[0][2] += moon[1][2]

    for p, v in moons:
        e += (abs(p[0])+abs(p[1])+abs(p[2]))*(abs(v[0])+abs(v[1])+abs(v[2]))

    assert e == 9139


def test_day12b():
    """
    Finished with helpful hints from ZuBsPaCe
    https://www.reddit.com/r/adventofcode/comments/e9jxh2/help_2019_day_12_part_2_what_am_i_not_seeing/far9cgu/
    """
    moons = [[m, [0, 0, 0]] for m in get_moons()]
    com = []
    for i in range(3):
        count = 0
        initial = deepcopy(moons)
        while True:
            for me, other in permutations(moons, 2):
                pa = me[0]
                pb = other[0]
                me[1][i] += -1 if pa[i] > pb[i] else 1 if pa[i] < pb[i] else 0
            for moon in moons:
                moon[0][i] += moon[1][i]
            count += 1
            if moons == initial:
                break
        com.append(count)
    steps = reduce(lambda a, b: int(a * b / gcd(a, b)), com)
    assert steps == 420788524631496