defmodule Hangman.Game do

  alias Hangman.Game
  # start with declaring a struct
  defstruct(
    game_state: :initializing,
    turns_left: 7,
    letters: [],
    used: []
  )

  def new_game do
    %Game{letters: String.codepoints("hello")}
  end

  def new_game(word) do
    %Game{letters: String.codepoints(word)}
  end

  def play(game, guess) do
    make_move(game, guess ,Enum.member?(game.used, guess))
  end

  def make_move(game, _ ,_already_guess=true) do
    Map.put(game, :game_state, :already_guess)
  end

  def make_move(game, guess, _already_guess=false) do
    game = Map.put(game, :used, [guess | game.used])
    check_guess(game, Enum.member?(game.letters, guess))
  end

  def check_guess(game, _correct_guess=true) do
    check_game_won(game, MapSet.subset?(MapSet.new(game.letters), MapSet.new(game.used)))
  end

  def check_guess(game, _correct_guess=false) do
    Map.put(game, :game_state, :bad_guess)
  end

  def check_game_won(game, _won=true) do
    Map.put(game, :game_state, :won)
  end

  def check_game_won(game, _won=false) do
    Map.put(game, :game_state, :good_guess)
  end

end