Day 10

Mix.install([
  {:req, "~> 0.3.2"},
  {:vega_lite, "~> 0.1.6"},
  {:kino_vega_lite, "~> 0.1.6"}
])

alias VegaLite, as: Vl

day = 10

aoc_session = System.fetch_env!("LB_AOC_SESSION")
input_url = "https://adventofcode.com/2022/day/#{day}/input"
{:ok, %{body: input}} = Req.get(input_url, headers: [cookie: "session=#{aoc_session}"])

Input

test_input = """
addx 15
addx -11
addx 6
addx -3
addx 5
addx -1
addx -8
addx 13
addx 4
noop
addx -1
addx 5
addx -1
addx 5
addx -1
addx 5
addx -1
addx 5
addx -1
addx -35
addx 1
addx 24
addx -19
addx 1
addx 16
addx -11
noop
noop
addx 21
addx -15
noop
noop
addx -3
addx 9
addx 1
addx -3
addx 8
addx 1
addx 5
noop
noop
noop
noop
noop
addx -36
noop
addx 1
addx 7
noop
noop
noop
addx 2
addx 6
noop
noop
noop
noop
noop
addx 1
noop
noop
addx 7
addx 1
noop
addx -13
addx 13
addx 7
noop
addx 1
addx -33
noop
noop
noop
addx 2
noop
noop
noop
addx 8
noop
addx -1
addx 2
addx 1
noop
addx 17
addx -9
addx 1
addx 1
addx -3
addx 11
noop
noop
addx 1
noop
addx 1
noop
noop
addx -13
addx -19
addx 1
addx 3
addx 26
addx -30
addx 12
addx -1
addx 3
addx 1
noop
noop
noop
addx -9
addx 18
addx 1
addx 2
noop
noop
addx 9
noop
noop
noop
addx -1
addx 2
addx -37
addx 1
addx 3
noop
addx 15
addx -21
addx 22
addx -6
addx 1
noop
addx 2
addx 1
noop
addx -10
noop
noop
addx 20
addx 1
addx 2
addx 2
addx -6
addx -11
noop
noop
noop
"""

Part 1

defmodule Part1 do
  def register_values(input) do
    input
    |> Enum.reduce({[1], 1}, fn
      "noop", {lst, val} ->
        {[val | lst], val}

      "addx " <> n, {lst, val} ->
        n = String.to_integer(n)
        {[val + n | [val | lst]], val + n}
    end)
    |> elem(0)
    |> Enum.reverse()
    |> Enum.with_index(1)
  end

  def solve(input) do
    input
    |> String.split("\n", trim: true)
    |> register_values()
    |> Enum.drop(19)
    |> Enum.take_every(40)
    |> Enum.map(fn {n, i} -> n * i end)
    |> Enum.sum()
  end
end

Part1.solve(test_input)

lst = [:a, :b, :c]
[:y | [:z | lst]]

Part 2

defmodule Part2 do
  def pixel_array(input) do
    input
    |> String.split("\n", trim: true)
    |> Part1.register_values()
    |> Enum.map(fn {middle_pixel, during_cycle} ->
      pixel_being_drawn = rem(during_cycle - 1, 40)
      pixel_being_drawn in (middle_pixel - 1)..(middle_pixel + 1)
    end)
  end

  def solve(input) do
    pixel_array(input)
    |> Enum.map(fn is_on -> if is_on, do: "#", else: "." end)
    |> Enum.chunk_every(40)
    |> Enum.map(&Enum.join/1)
    |> Enum.join("\n")
    |> IO.puts()
  end

  def solve_vega_lite(input) do
    data =
      pixel_array(input)
      |> Enum.chunk_every(40)
      |> Enum.with_index()
      |> Enum.map(fn {row, r} ->
        for {is_on, c} <- Enum.with_index(row),
            do: %{lit: is_on, x: c, y: r}
      end)
      |> List.flatten()
      |> Enum.filter(fn m -> m.lit end)

    Vl.new()
    |> Vl.data_from_values(data)
    |> Vl.mark(:rect)
    |> Vl.encode_field(:x, "x")
    |> Vl.encode_field(:y, "y")
    |> Vl.en()
  end
end

Part2.solve_vega_lite(input)