Creating a basic hangman game

new rails

rails new  --webpack --skip-sprockets  -d postgresql --skip-spring --skip-turbolinks hangman

first model: vocabulry with words

$ rails generate model vocabulary word

  invoke  active_record
  create    db/migrate/20200512175829_create_vocabularies.rb
  create    app/models/vocabulary.rb
  invoke    test_unit
  create      test/models/vocabulary_test.rb
  create      test/fixtures/vocabularies.yml    

oops, I did not want a table "vocabularies". let's roll this generator back

$ rails destroy model vocabulary word
      invoke  active_record
      remove    db/migrate/20200512175829_create_vocabularies.rb
      remove    app/models/vocabulary.rb
      invoke    test_unit
      remove      test/models/vocabulary_test.rb
      remove      test/fixtures/vocabularies.yml

in file config/initializers/inflections.rb we can add an irregular plural:

ActiveSupport::Inflector.inflections(:en) do |inflect|
  inflect.uncountable ['sheep', 'vocabulary']
end

$ rails generate model vocabulary word
      invoke  active_record
      create    db/migrate/20200512180416_create_vocabulary.rb
      create    app/models/vocabulary.rb
      invoke    test_unit
      create      test/models/vocabulary_test.rb
      create      test/fixtures/vocabulary.yml  

time to add some seeds and fixtures:

# seeds.rb
Vocabulary.create(word: 'javascript')
Vocabulary.create(word: 'internet')
Vocabulary.create(word: 'refactoring')

# vocabulary.yml
one:
  word: javascript

two:
  word: internet

three:
  word: refactoring

start the database

createdb hangman_development
createdb hangman_test
rails db:migrate

users

rails g controller static home
bundle add devise
rails g devise:install
rails g devise User

guest user

bundle add  devise-guests
rails g devise_guests User
rails db:migrate

now every visitor is assigned a guest user automatically even before signing in:

  <% if user_signed_in? %>
    <%= link_to "Users", users_path %>
    <%= link_to "Logout #{current_user}", logout_path %>
  <% else %>
    <%= link_to "Register", new_user_registration_path %>
    <%= link_to "Login", new_user_session_path %>
    You are a guest user <%= guest_user %>
  <% end %>

game, game_state and the gem "acts as state machine" aasm

See https://github.com/aasm/aasm

bundle add aasm
rails g scaffold game game_state word closed_at:timestamp

create_table :games do |t|
  t.string :game_state
  t.string :word
  t.timestamp :closed_at
  t.timestamps
end    

implement the game logic using TDD, starting with these tests:

test "game can be created by user" do
  u = users(:one)

  g = Game.start(user: u)
  assert_equal g.players.count, 1
  assert_equal g.players.find_by(color: 'white').user_id, u.id
  assert g.lobby?
end

test "2nd player can join a game in lobby-state" do
  u1 = users(:one)
  u2 = users(:two)
  g = Game.start(user: u1)
  g.join(u2)

  assert_equal g.players.count, 2
  assert_equal g.players.find_by(color: 'black').user_id, u2.id
  assert_nil g.closed_at
  assert g.waiting_for_black?
end

test "player can guess" do
  u1 = users(:one)
  u2 = users(:two)
  g = Game.start(user: u1)
  g.join(u2)
  g.update(word: 'abba', mask: '____')

  g.guess('x')

  assert_equal g.mask, '____'
  assert_nil g.closed_at
  assert g.waiting_for_white?

  g.guess('a')

  assert_equal g.mask, 'a__a'
  assert_nil g.closed_at
  assert g.waiting_for_white?

  g.guess('b')

  assert_equal g.mask, 'abba'
  assert g.white_won?
  refute_nil g.closed_at
  assert_operator g.closed_at.to_i, :<=, Time.now.to_i
end  

display game state

create a view to display the game:

<div class="layout">
  <div class="player white <%= if @game.waiting_for_white? then 'current' end %>  <%= if @game.white_won? then 'winner' end %>">
    <% if @game.players.count > 0 %>
      <h2>Player White <%= if @game.white_won? then 'has won' end %></h2>
      <p><%= @game.white_player.no_of_guesses %> guesses, 
      <%= @game.white_player.no_of_fails %> fails.</p>
    <% end %>
  </div>

  <div class="board">
    <%= @game.mask %>
  </div>

  <div class="player black <%= if @game.waiting_for_black? then 'current' end %> <%= if @game.black_won? then 'winner' end %>">
    <% if @game.players.count > 1 %>
      <h2>Player Black <%= if @game.black_won? then 'has won' end %></h2>
      <p><%= @game.black_player.no_of_guesses %> guesses, 
      <%= @game.black_player.no_of_fails %> fails.</p>
    <% else %>
      <h2>Waiting for second player</h2>
    <% end %>
  </div>  
</div>