#! /usr/bin/env python3
from typing import Iterable
# from typing import Tuple
from typing import Set
from typing import Dict
# from typing import Optional

import itertools
from collections import Counter
from collections import namedtuple


Point = namedtuple("Point", "x y")

D2P = {
    "se": Point(1, -1),
    "sw": Point(-1, -1),
    "ne": Point(1, 1),
    "nw": Point(-1, 1),
    "w": Point(-2, 0),
    "e": Point(2, 0),
}


def directions_to_point(s: str) -> Point:
    point = Point(0, 0)
    direction = ""
    for c in s:
        direction += c
        if direction in D2P:
            point = add_points(point, D2P[direction])
            direction = ""

    if direction != "":
        raise ValueError("Something left over unexpectedly")

    return point


def add_points(p1, p2) -> Point:
    return Point(
        p1.x + p2.x,
        p1.y + p2.y,
    )


def neighbors(point: Point) -> Iterable[Point]:
    for diff in D2P.values():
        yield add_points(point, diff)


def neighbor_counts(points: Set[Point]) -> Dict[Point, int]:
    # return {
    #     p: sum(map(lambda x: 1 if x in points else 0, neighbors(p)))
    #     for p in points
    # }
    return Counter(itertools.chain.from_iterable(map(neighbors, points)))


def next_generation(points: Set[Point]):
    counts = neighbor_counts(points)
    return (
        {p for p in points if counts[p] in (1, 2)} |
        {p for p in counts if p not in points and counts[p] == 2}
    )


def point_deltas() -> Iterable[Point]:
    return D2P.values()


def life(points: Set[Point], n: int) -> Set[Point]:
    for r in range(n):
        points = next_generation(points)

    return points


def sample():
    black: Set[Point] = set()
    for line in (
        "sesenwnenenewseeswwswswwnenewsewsw",
        "neeenesenwnwwswnenewnwwsewnenwseswesw",
        "seswneswswsenwwnwse",
        "nwnwneseeswswnenewneswwnewseswneseene",
        "swweswneswnenwsewnwneneseenw",
        "eesenwseswswnenwswnwnwsewwnwsene",
        "sewnenenenesenwsewnenwwwse",
        "wenwwweseeeweswwwnwwe",
        "wsweesenenewnwwnwsenewsenwwsesesenwne",
        "neeswseenwwswnwswswnw",
        "nenwswwsewswnenenewsenwsenwnesesenew",
        "enewnwewneswsewnwswenweswnenwsenwsw",
        "sweneswneswneneenwnewenewwneswswnese",
        "swwesenesewenwneswnwwneseswwne",
        "enesenwswwswneneswsenwnewswseenwsese",
        "wnwnesenesenenwwnenwsewesewsesesew",
        "nenewswnwewswnenesenwnesewesw",
        "eneswnwswnwsenenwnwnwwseeswneewsenese",
        "neswnwewnwnwseenwseesewsenwsweewe",
        "wseweeenwnesenwwwswnew",
    ):
        p = directions_to_point(line)
        if p in black:
            black.remove(p)
        else:
            black.add(p)

    print(f"Num black is {len(black)}")

    rounds = 100
    black = life(black, rounds)
    print(f"Num black after {rounds} is {len(black)}")


def part2():
    black: Set[Point] = set()
    with open("input.txt") as f:
        for line in f:
            line = line.strip()
            p = directions_to_point(line)
            if p in black:
                black.remove(p)
            else:
                black.add(p)

    print(f"Num black is {len(black)}")

    rounds = 100
    black = life(black, rounds)
    print(f"Num black after {rounds} is {len(black)}")


if __name__ == "__main__":
    # sample()
    part2()