defmodule Animals do
  @moduledoc """
  Documentation for `Animals`.
  """

  @doc """
  Hello world.

  ## Examples

      iex> Animals.hello()
      :world

  """
  def hello do
    :world
  end

  def create_zoo do
    (["lion", "tiger", "gorilla", "elephant", "monkey", "giraffe"] ++ ["snake"]) -- ["lion"]
  end

  def randomize(zoo) do
    Enum.shuffle(zoo)
  end

  def contains?(zoo, animal) do
    Enum.member?(zoo, animal)
  end

  def see_animals(zoo, count) do
    {_seen, to_see} = Enum.split(zoo, -count)
    to_see
  end

  def save(zoo, filename) do
    binary = :erlang.term_to_binary(zoo)
    File.write(filename, binary)
  end

  def load(filename) do
    case File.read(filename) do
      {:ok, binary} -> :erlang.binary_to_term(binary)
      {:error, _reason} -> "File does not exist"
    end
  end

  @doc """
    Makes a selection
  """
  def selection(number_of_animals) do
    # Todo: what happens when create_zoo() passes two args to randomize(), i.e. tuple
    Animals.create_zoo()
    |> Animals.randomize()
    |> Animals.see_animals(number_of_animals)
  end
end