day9.exs

defmodule Day9 do
  def remove_bangs(line) do
    Regex.replace(~r{!.}, line, "") 
  end

  def count_garbage(line) do
    IO.puts("Garbage Chars: ")
    Regex.scan(~r{<.*?>}, line)
    |> Enum.flat_map(&(&1))
    |> Enum.reduce(0, fn(el, acc) -> acc + String.length(el) - 2 end)
    |> IO.puts
    line
  end

  def remove_garbage(line) do    
    Regex.replace(~r{<.*?>}, line, "") 
  end

  def count_score("", level, score) do
    level + score
  end

  def count_score(line, level, score) do
    count_score(
      String.slice(line,1,String.length(line)),
      case String.at(line, 0) do
        "{" -> level + 1
        "}" -> level - 1
        _   -> level
      end,
      case String.at(line, 0) do
        "}" -> level + score
        _   -> score
      end
    )
  end

  def count_score(line) do
    count_score(line, 0, 0)
  end
end

IO.stream(:stdio, :line)
|> Enum.map(&Day9.remove_bangs/1)
|> Enum.map(&Day9.count_garbage/1)
|> Enum.map(&Day9.remove_garbage/1)
|> Enum.map(&Day9.count_score/1)
|> IO.inspect(charlists: :as_lists)