zerosleeps

from pathlib import Path
import re
import unittest

def get_raw_input():
    return (Path(__file__).parent/'day_21_input.txt').read_text()

class Food():
    def __init__(self, raw_line):
        self.raw_line = raw_line

    def parse_raw_line(self):
        regexp = re.compile(r'^(?P<ingredients>.*) \(contains (?P<contains>.*)\)$')
        return re.match(regexp, self.raw_line)

    @property
    def ingredients(self):
        return self.parse_raw_line()['ingredients'].split()

    @property
    def contains(self):
        return self.parse_raw_line()['contains'].split(', ')

def build_allergens(foods):
    allergens = {}
    for food in foods:
        for contains in food.contains:
            if contains in allergens:
                allergens[contains] &= set(food.ingredients)
            else:
                allergens[contains] = set(food.ingredients)

    while any([len(ingredients) > 1 for ingredients in allergens.values()]):
        # Find allergents with only one possible ingredient, and remove that
        # ingredient from all other allergens
        for allergen, ingredients in allergens.items():
            if len(ingredients) == 1:
                for update_allergen in allergens:
                    if update_allergen != allergen:
                        allergens[update_allergen] -= ingredients

    return allergens

def build_no_allergens(foods, allergens):
    return [
        ingredient
        for food in foods
        for ingredient in food.ingredients
        if ingredient not in [
            allergen_ingredient
            for allergen in allergens.values()
            for allergen_ingredient in allergen
        ]
    ]

def part_one(raw_input):
    foods = [Food(raw_line) for raw_line in raw_input.strip().splitlines()]
    allergens = build_allergens(foods)
    return len(build_no_allergens(foods,allergens))

def part_two(raw_input):
    foods = [Food(raw_line) for raw_line in raw_input.strip().splitlines()]
    allergens = build_allergens(foods)
    return ','.join([allergens[allergen].pop() for allergen in sorted(allergens)])

class TestPartOne(unittest.TestCase):
    def test_part_one_example(self):
        self.assertEqual(part_one("mxmxvkd kfcds sqjhc nhms (contains dairy, fish)\ntrh fvjkl sbzzf mxmxvkd (contains dairy)\nsqjhc fvjkl (contains soy)\nsqjhc mxmxvkd sbzzf (contains fish)"), 5)

class TestPartTwo(unittest.TestCase):
    def test_part_two_example(self):
        self.assertEqual(part_two("mxmxvkd kfcds sqjhc nhms (contains dairy, fish)\ntrh fvjkl sbzzf mxmxvkd (contains dairy)\nsqjhc fvjkl (contains soy)\nsqjhc mxmxvkd sbzzf (contains fish)"), 'mxmxvkd,sqjhc,fvjkl')

if __name__ == '__main__':
    print(f'Part one: {part_one(get_raw_input())}')
    print(f'Part two: {part_two(get_raw_input())}')