# --- Day 8: Two-Factor Authentication ---

# You come across a door implementing what you can only assume is an
# implementation of two-factor authentication after a long game of
# requirements telephone.

# To get past the door, you first swipe a keycard (no problem; there was one on
# a nearby desk). Then, it displays a code on a little screen, and you type
# that code on a keypad. Then, presumably, the door unlocks.

# Unfortunately, the screen has been smashed. After a few minutes, you've taken
# everything apart and figured out how it works. Now you just have to work out
# what the screen would have displayed.

# The magnetic strip on the card you swiped encodes a series of instructions
# for the screen; these instructions are your puzzle input. The screen is 50
# pixels wide and 6 pixels tall, all of which start off, and is capable of
# three somewhat peculiar operations:

#     rect AxB turns on all of the pixels in a rectangle at the top-left of the
# screen which is A wide and B tall.
#     rotate row y=A by B shifts all of the pixels in row A (0 is the top row)
# right by B pixels. Pixels that would fall off the right end appear at the
# left end of the row.
#     rotate column x=A by B shifts all of the pixels in column A (0 is the
# left column) down by B pixels. Pixels that would fall off the bottom appear
# at the top of the column.

# For example, here is a simple sequence on a smaller screen:

#     rect 3x2 creates a small rectangle in the top-left corner:

#     ###....
#     ###....
#     .......

#     rotate column x=1 by 1 rotates the second column down by one pixel:

#     #.#....
#     ###....
#     .#.....

#     rotate row y=0 by 4 rotates the top row right by four pixels:

#     ....#.#
#     ###....
#     .#.....

#     rotate column x=1 by 1 again rotates the second column down by one pixel,
# causing the bottom pixel to wrap back to the top:

#     .#..#.#
#     #.#....
#     .#.....

# As you can see, this display technology is extremely powerful, and will soon
# dominate the tiny-code-displaying-screen market. That's what the
# advertisement on the back of the display tries to convince you, anyway.

# There seems to be an intermediate check of the voltage used by the display:
# after you swipe your card, if the screen did work, how many pixels should be
# lit?

import numpy as np
import numpy.typing as npt

with open("files/P8.txt") as f:
    instructions = [line for line in f.read().strip().split("\n")]


def rect(instruction: str, grid: npt.NDArray[int]) -> npt.NDArray[int]:
    _, row = instruction.split("x")
    _, col = _.split()
    grid[: int(row), : int(col)] = 1


def rotate_column(
    instruction: str, grid: npt.NDArray[int]
) -> npt.NDArray[int]:
    _, cols = instruction.split("=")
    x, _, steps = cols.split()
    new_col = np.roll(grid[:, int(x) : int(x) + 1], int(steps), axis=0)
    grid[:, int(x) : int(x) + 1] = new_col


def rotate_row(instruction: str, grid: npt.NDArray[int]) -> npt.NDArray[int]:
    _, rows = instruction.split("=")
    y, _, steps = rows.split()
    new_row = np.roll(grid[int(y) : int(y) + 1, :], int(steps), axis=1)
    grid[int(y) : int(y) + 1, :] = new_row


# dimensions given by the problem
init_grid = np.zeros((6, 50), dtype=int)


def part_1() -> None:

    for instruction in instructions:
        if instruction.startswith("rect"):
            rect(instruction, init_grid)
        elif instruction.startswith("rotate row"):
            rotate_row(instruction, init_grid)
        elif instruction.startswith("rotate column"):
            rotate_column(instruction, init_grid)

    lit = np.sum(init_grid)

    print(f"There should be {lit} pixels lit")


# --- Part Two ---

# You notice that the screen is only capable of displaying capital letters; in
# the font it uses, each letter is 5 pixels wide and 6 tall.

# After you swipe your card, what code is the screen trying to display?


def display(grid: npt.NDArray[int]) -> None:
    print(
        "\n".join("".join("X" if one else " " for one in row) for row in grid)
    )


def part_2() -> None:
    print("The code is the following:\n")
    display(init_grid)


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