Day Ten

Mix.install([
  {:kino, "~> 0.7.0"}
])

Section

input = Kino.Input.textarea("Input")

defmodule DayTen do
  def solve1(input) do
    input
    |> String.split("\n", trim: true)
    |> Enum.flat_map_reduce(1, &eval/2)
    |> elem(0)
    |> score()
  end

  def solve2(input) do
    input
    |> String.split("\n", trim: true)
    |> Enum.flat_map_reduce(1, &eval/2)
    |> elem(0)
    |> draw()
  end

  defp eval("noop", x) do
    {[x], x}
  end

  defp eval("addx " <> inc, x) do
    new_x = x + String.to_integer(inc)
    {[x, x], new_x}
  end

  defp score(xs) do
    xs
    |> Enum.with_index(1)
    |> Enum.drop(19)
    |> Enum.take_every(40)
    |> Enum.map(fn {a, b} -> a * b end)
    |> Enum.sum()
  end

  defp draw(xs) do
    xs
    |> Enum.chunk_every(40)
    |> Enum.each(fn line ->
      line
      |> Enum.with_index()
      |> Enum.each(fn {x, i} ->
        if abs(x - i) <= 1 do
          IO.write("#")
        else
          IO.write(".")
        end
      end)

      IO.puts("")
    end)
  end
end

DayTen.solve2(Kino.Input.read(input))