containers =
  File.stream!("inputs/day17.txt")
  |> Stream.map(&String.trim/1)
  |> Stream.filter(&(&1 != ""))
  |> Enum.map(fn line ->
    {num, ""} = Integer.parse(line)
    num
  end)

defmodule EggnogStorage do
  use Agent

  def start do
    Agent.start_link(fn -> %{} end, name: __MODULE__)
  end

  def combinations(_containers, 0) do
    [[]]
  end

  def combinations([], _remainingCapacity) do
    []
  end

  def combinations(containers, remainingCapacity) do
    cached_value = Agent.get(__MODULE__, &Map.get(&1, {containers, remainingCapacity}))

    if cached_value do
      cached_value
    else
      [nextContainer | remainingContainers] = containers

      combinationsWithThisContainer =
        if nextContainer <= remainingCapacity do
          Enum.map(
            combinations(remainingContainers, remainingCapacity - nextContainer),
            fn x -> [nextContainer | x] end
          )
        else
          []
        end

      combinationsWithoutThisContainer = combinations(remainingContainers, remainingCapacity)

      result = combinationsWithThisContainer ++ combinationsWithoutThisContainer

      Agent.update(__MODULE__, &Map.put(&1, {containers, remainingCapacity}, result))
      result
    end
  end
end

{:ok, _} = EggnogStorage.start()

combinations = EggnogStorage.combinations(containers, 150)
IO.puts("Combinations: #{length(combinations)}")

frequencies = Enum.map(combinations, &length/1) |> Enum.frequencies()
dbg(frequencies)