# -*- coding: utf-8 -*-
from abc import ABC
from copy import copy
from dataclasses import dataclass
from typing import Tuple, Iterator, List, Set

from aoc import BaseAssignment


@dataclass
class Coordinate:
    x: int
    y: int

    def __hash__(self):
        return tuple([self.x, self.y]).__hash__()

    def __sub__(self, other: "Coordinate"):
        return Coordinate(self.x - other.x, self.y - other.y)

    @property
    def polarity_x(self):
        try:
            return abs(self.x) / self.x
        except ZeroDivisionError:
            return 0

    @property
    def polarity_y(self):
        try:
            return abs(self.y) / self.y
        except ZeroDivisionError:
            return 0


class Assignment(BaseAssignment, ABC):
    rope_length = NotImplemented

    def parse_line(self, item: str) -> Tuple[str, int]:
        direction, amount = item.split(" ")
        return direction, int(amount)

    def move(self, direction: str, amount: int):
        pass

    @staticmethod
    def next_head(head: Coordinate, direction: str):
        match direction:
            case "R":
                head.x += 1
            case "L":
                head.x -= 1
            case "U":
                head.y += 1
            case "D":
                head.y -= 1

    @staticmethod
    def next_knot(head: Coordinate, tail: Coordinate):
        delta = head - tail

        if abs(delta.x) > 1 and delta.y == 0:
            tail.x += delta.x - delta.polarity_x
        if abs(delta.x) > 1 and abs(delta.y) == 1:
            tail.x += delta.x - delta.polarity_x
            tail.y += delta.y
        if abs(delta.y) > 1 and delta.x == 0:
            tail.y += delta.y - delta.polarity_y
        if abs(delta.y) > 1 and abs(delta.x) == 1:
            tail.y += delta.y - delta.polarity_y
            tail.x += delta.x

    def tail_positions(self, input: Iterator[str], length: int) -> Iterator[Coordinate]:
        knots = [Coordinate(0, 0) for _ in range(length)]

        for line in input:
            direction, amount = self.parse_line(line)

            for _ in range(amount):
                for index in range(length):
                    if index == 0:
                        self.next_head(knots[index], direction)
                        continue

                    self.next_knot(knots[index - 1], knots[index])

                yield knots[length - 1]

    def unique_tail_positions(
        self, input: Iterator[str], length: int
    ) -> Set[Coordinate]:
        unique_tail_positions = set()

        for position in self.tail_positions(input, length):
            unique_tail_positions.add(copy(position))

        return unique_tail_positions

    def visualize(self, width: range, height: range, positions: Set[Coordinate]):
        rows = []
        for y in height:
            items = []
            for x in width:
                if x == 0 and y == 0:
                    items.append("s")
                elif Coordinate(x, y) in positions:
                    items.append("#")
                else:
                    items.append(".")
            rows.append(items)

        return "\n".join(["".join(row) for row in reversed(rows)])

    def run(self, input: Iterator) -> int:
        unique_positions = self.unique_tail_positions(input, length=self.rope_length)
        return len(unique_positions)


class AssignmentOne(Assignment):
    example_result = 13
    rope_length = 2


class AssignmentTwo(Assignment):
    example_result = 36
    rope_length = 10