day_01.ex

defmodule Aoc.Y2019.Day01 do
  @moduledoc """
  Solved https://adventofcode.com/2019/day/1
  """
  import Aoc.Helper.IO

  def run_part1(),
    do:
      get_string_input("2019", "01")
      |> String.split("\n")
      |> Enum.map(&String.to_integer/1)
      |> solve_part1()

  def run_part2(),
    do:
      get_string_input("2019", "01")
      |> String.split("\n")
      |> Enum.map(&String.to_integer/1)
      |> solve_part2()

  def solve_part1(data) do
    data
    |> Enum.map(&get_fuel_req/1)
    |> Enum.sum()
  end

  def solve_part2(data) do
    data
    |> Enum.map(&get_added_fuel/1)
    |> Enum.sum()
  end

  def get_input do
    {:ok, data} = File.read("input.txt")

    String.split(data, ["\n"])
    |> Enum.filter(fn item -> item != "" end)
    |> Enum.map(&String.to_integer/1)
  end

  defp get_fuel_req(mass), do: div(mass, 3) - 2

  defp get_added_fuel(mass) do
    value = get_fuel_req(mass)
    if value > 0, do: value + get_added_fuel(value), else: 0
  end

  def solved_status(), do: :solved
end