marco_elixir_study

defmodule Cards do
  @moduledoc """
    Provides methods for creating and handleing a deck of cards
  """

  @doc """
    Creates a list of strings that represents the deck of cards
  """
  def create_deck do
    values = ["Ace", "Two", "Three", "Four", "Five", "Six",
      "Seven", "Eight", "Nine", "Ten", "J", "Q", "K"]
    suits = ["Spades", "Clubs", "Hearts", "Diamonds"]

    for value <- values, suit <- suits do
      "#{value} of #{suit}"
    end
  end

  def shuffle(deck) do
    Enum.shuffle(deck)
  end

  @doc """
    Divides a deck into a hand and the rest of the cards.
    The `hand_size` argument determine how many cards will be in the hand

    ** Examples **
          
        iex> deck = Cards.create_deck
        iex> {hand, _deck} = Cards.deal(deck, 1)
        iex> hand
        ["Ace of Spades"]
  """
  def deal(deck, hand_size) do
    Enum.split(deck, hand_size)
  end

  @doc """
    Determines whether a dack contains a given card throught the `card` argument

    ** Example **
      iex> deck = Cards.create_deck
      iex> Cards.contains?(deck, "Ace of Spades")
      true

  """

  def contains?(deck, card) do
    Enum.member?(deck, card)
  end

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

  def load(filename) do
    # in this case statement we're doing two operations at the 
    # same time using patterns matching (comparison and assignment)
    case File.read(filename) do
      {:ok, binary} -> :erlang.binary_to_term(binary)
      {:error, _reason} -> "That file does not exist"
    end
  end

  def create_hand(hand_size) do
    Cards.create_deck
    |> Cards.shuffle
    |> Cards.deal(hand_size)
  end

end