# --- Day 14: Chocolate Charts ---

# You finally have a chance to look at all of the produce moving around.
# Chocolate, cinnamon, mint, chili peppers, nutmeg, vanilla... the Elves must be
# growing these plants to make hot chocolate! As you realize this, you hear a
# conversation in the distance. When you go to investigate, you discover two
# Elves in what appears to be a makeshift underground kitchen/laboratory.

# The Elves are trying to come up with the ultimate hot chocolate recipe;
# they're even maintaining a scoreboard which tracks the quality score (0-9) of
# each recipe.

# Only two recipes are on the board: the first recipe got a score of 3, the
# second, 7. Each of the two Elves has a current recipe: the first Elf starts
# with the first recipe, and the second Elf starts with the second recipe.

# To create new recipes, the two Elves combine their current recipes. This
# creates new recipes from the digits of the sum of the current recipes' scores.
# With the current recipes' scores of 3 and 7, their sum is 10, and so two new
# recipes would be created: the first with score 1 and the second with score 0.
# If the current recipes' scores were 2 and 3, the sum, 5, would only create one
# recipe (with a score of 5) with its single digit.

# The new recipes are added to the end of the scoreboard in the order they are
# created. So, after the first round, the scoreboard is 3, 7, 1, 0.

# After all new recipes are added to the scoreboard, each Elf picks a new
# current recipe. To do this, the Elf steps forward through the scoreboard a
# number of recipes equal to 1 plus the score of their current recipe. So, after
# the first round, the first Elf moves forward 1 + 3 = 4 times, while the second
# Elf moves forward 1 + 7 = 8 times. If they run out of recipes, they loop back
# around to the beginning. After the first round, both Elves happen to loop
# around until they land on the same recipe that they had in the beginning; in
# general, they will move to different recipes.

# Drawing the first Elf as parentheses and the second Elf as square brackets,
# they continue this process:

# (3)[7]
# (3)[7] 1  0
#  3  7  1 [0](1) 0
#  3  7  1  0 [1] 0 (1)
# (3) 7  1  0  1  0 [1] 2
#  3  7  1  0 (1) 0  1  2 [4]
#  3  7  1 [0] 1  0 (1) 2  4  5
#  3  7  1  0 [1] 0  1  2 (4) 5  1
#  3 (7) 1  0  1  0 [1] 2  4  5  1  5
#  3  7  1  0  1  0  1  2 [4](5) 1  5  8
#  3 (7) 1  0  1  0  1  2  4  5  1  5  8 [9]
#  3  7  1  0  1  0  1 [2] 4 (5) 1  5  8  9  1  6
#  3  7  1  0  1  0  1  2  4  5 [1] 5  8  9  1 (6) 7
#  3  7  1  0 (1) 0  1  2  4  5  1  5 [8] 9  1  6  7  7
#  3  7 [1] 0  1  0 (1) 2  4  5  1  5  8  9  1  6  7  7  9
#  3  7  1  0 [1] 0  1  2 (4) 5  1  5  8  9  1  6  7  7  9  2

# The Elves think their skill will improve after making a few recipes (your
# puzzle input). However, that could take ages; you can speed this up
# considerably by identifying the scores of the ten recipes after that.
# For example:

#     If the Elves think their skill will improve after making 9 recipes, the
# scores of the ten recipes after the first nine on the scoreboard would be
# 5158916779 (highlighted in the last line of the diagram).
#     After 5 recipes, the scores of the next ten would be 0124515891.
#     After 18 recipes, the scores of the next ten would be 9251071085.
#     After 2018 recipes, the scores of the next ten would be 5941429882.

# What are the scores of the ten recipes immediately after the number of recipes
# in your puzzle input?


def part_1() -> None:
    target_recipes = int(open("files/P14.txt").read())
    recipes = [3, 7]
    elf1, elf2 = 0, 1

    while len(recipes) < target_recipes + 10:
        recipes += list(map(int, list(str(recipes[elf1] + recipes[elf2]))))

        lr = len(recipes)
        elf1 = (elf1 + int(recipes[elf1]) + 1) % lr
        elf2 = (elf2 + int(recipes[elf2]) + 1) % lr

    scores = "".join(map(str, recipes[target_recipes : target_recipes + 10]))

    print(f"The scores are {scores}")


# --- Part Two ---

# As it turns out, you got the Elves' plan backwards. They actually want to know
# how many recipes appear on the scoreboard to the left of the first recipes
# whose scores are the digits from your puzzle input.

#     51589 first appears after 9 recipes.
#     01245 first appears after 5 recipes.
#     92510 first appears after 18 recipes.
#     59414 first appears after 2018 recipes.

# How many recipes appear on the scoreboard to the left of the score sequence
# in your puzzle input?


def part_2() -> None:
    target_recipe = [
        int(i)
        for num in open("files/P14.txt").read().splitlines()
        for i in num
    ]
    recipes = [3, 7]
    elf1, elf2 = 0, 1

    # The second part of this condition ensures that the recipe is found even
    # if it is finished by the '1' in the tens column of a sum.
    while (
        target_recipe != recipes[-len(target_recipe) :]
        and target_recipe != recipes[-(len(target_recipe) + 1) : -1]
    ):
        score = recipes[elf1] + recipes[elf2]

        if score >= 10:
            recipes.append(1)
            recipes.append(score - 10)
        else:
            recipes.append(score)

        lr = len(recipes)
        elf1 = (elf1 + int(recipes[elf1]) + 1) % lr
        elf2 = (elf2 + int(recipes[elf2]) + 1) % lr

    nrecipes = (
        len(recipes)
        - int(recipes[-len(target_recipe) :] != target_recipe)
        - len(target_recipe)
    )
    print(f"There are {nrecipes} recipes")


if __name__ == "__main__":
    part_1()
    part_2()