def part1(input_text):
    orbits = [string.split(')') for string in input_text]

    orbit_tree = {}

    for orbit in orbits:
        orbit_tree.setdefault(orbit[0], set())
        orbit_tree[orbit[0]].add(orbit[1])

    count = 0
    depth = 0
    current_level = set()
    next_level = set(['COM'])

    while len(next_level) > 0:
        depth += 1
        current_level, next_level = next_level, set()

        for node in current_level:
            try:
                count += depth * len(orbit_tree[node])
                next_level.update(orbit_tree[node])
            except KeyError:
                pass

    return count


def part2(input_text):
    orbits = [string.split(')') for string in input_text]

    parents = {orbit[1]: orbit[0] for orbit in orbits}

    you = ['YOU']
    while you[-1] != 'COM':
        you.append(parents[you[-1]])

    san = ['SAN']
    while san[-1] != 'COM':
        san.append(parents[san[-1]])

    ind = -1
    while you[ind] == san[ind]:
        ind -= 1

    meet = you[ind + 1]

    return you.index(meet) + san.index(meet) - 2


if __name__ == "__main__":
    with open("input_files/AoC2019_day06_input.txt") as f:
        input_text = f.read().split('\n')

    print('part 1:', part1(input_text))
    print('part 2:', part2(input_text))