Introduce stateful_enum and define ProgramSession state transitions

Gemfile

@@ -30,6 +30,8 @@ gem 'omniauth-github'
 gem 'omniauth-twitter'
 gem "omniauth-rails_csrf_protection", "~> 2.0"
 
+gem 'stateful_enum'
+
 gem 'actionview-encoded_mail_to'
 gem 'active_model_serializers', '~> 0.10.16'
 gem 'bootsnap', '~> 1.20', require: false

Gemfile.lock

@@ -428,6 +428,7 @@ GEM
     snaky_hash (2.0.1)
       hashie
       version_gem (~> 1.1, >= 1.1.1)
+    stateful_enum (0.7.0)
     stringio (3.2.0)
     temple (0.10.4)
     thor (1.4.0)
@@ -508,6 +509,7 @@ DEPENDENCIES
   sendgrid-ruby
   sidekiq
   simple_form
+  stateful_enum
   turbo-rails
 
 RUBY VERSION

app/models/invitation.rb

@@ -1,12 +1,9 @@
 class Invitation < ApplicationRecord
-  enum :state, {pending: 'pending', accepted: 'accepted', declined: 'declined'}
+  enum :state, {pending: 'pending', accepted: 'accepted', declined: 'declined'}, default: :pending
 
   belongs_to :proposal
   belongs_to :user, optional: true
 
-  scope :not_accepted, -> { where(state: [:pending, :declined]) }
-
-  before_create :set_default_state
   before_create :set_slug
 
   validates :email, presence: true
@@ -30,10 +27,6 @@ def decline
   def set_slug
     self.slug = Digest::SHA1.hexdigest([email, rand(1000)].map(&:to_s).join('-'))[0, 10]
   end
-
-  def set_default_state
-    self.state = :pending if state.nil?
-  end
 end
 
 # == Schema Information

app/models/program_session.rb

@@ -6,7 +6,22 @@ class ProgramSession < ApplicationRecord
     unconfirmed_waitlisted: 'unconfirmed waitlisted',
     confirmed_waitlisted: 'confirmed waitlisted',
     declined: 'declined'
-  }, default: :draft
+  }, default: :draft do
+    event :confirm do
+      transition :unconfirmed_waitlisted => :confirmed_waitlisted
+      transition :unconfirmed_accepted => :live
+    end
+
+    event :promote do
+      before do
+        proposal.promote if proposal
+      end
+
+      transition :draft => :live
+      transition :unconfirmed_waitlisted => :unconfirmed_accepted
+      transition :confirmed_waitlisted => :live
+    end
+  end
 
   STATE_GROUPS = {
     live: 'program',
@@ -17,16 +32,6 @@ class ProgramSession < ApplicationRecord
     declined: 'declined'
   }.with_indifferent_access
 
-  PROMOTIONS = {
-    draft: :live,
-    unconfirmed_waitlisted: :unconfirmed_accepted,
-    confirmed_waitlisted: :live
-  }.with_indifferent_access
-
-  CONFIRMATIONS = {
-    unconfirmed_waitlisted: :confirmed_waitlisted,
-    unconfirmed_accepted: :live
-  }.with_indifferent_access
 
   belongs_to :event
   belongs_to :proposal, optional: true
@@ -82,25 +87,6 @@ def self.create_from_proposal(proposal)
     end
   end
 
-  def can_confirm?
-    CONFIRMATIONS.key?(state)
-  end
-
-  def confirm
-    update(state: CONFIRMATIONS[state]) if can_confirm?
-  end
-
-  def can_promote?
-    PROMOTIONS.key?(state)
-  end
-
-  def promote
-    if proposal.present?
-      proposal.promote
-    end
-    update(state: PROMOTIONS[state])
-  end
-
   def multiple_speakers?
     speakers.count > 1
   end

spec/models/program_session_spec.rb

@@ -189,8 +189,7 @@
     end
 
     it "promotes it's proposal" do
-      ps = create(:program_session, proposal: proposal, track: proposal.track)
-      proposal = create(:proposal_with_track, program_session: ps)
+      ps = create(:program_session, state: :draft, proposal: proposal, track: proposal.track)
 
       expect(proposal).to receive(:promote)
       ps.promote