Add PushNotification creation logic

app/services/push_notifications/creator.rb

@@ -0,0 +1,21 @@
+module PushNotifications
+  class Creator
+    # Given an Event it will create as many PushNotification resources
+    # necessary as the resource associated to the Event will require.
+    #
+    # @param [Hash] event: <Event>
+    def initialize(event:)
+      @event = event
+    end
+
+    def create!
+      EventNotifier.new(event: event).users.each do
+        PushNotification.create!(event: event)
+      end
+    end
+
+    private
+
+    attr_accessor :event
+  end
+end

app/services/push_notifications/event_notifier.rb

@@ -0,0 +1,24 @@
+module PushNotifications
+  class EventNotifier
+    def initialize(event:)
+      @event = event
+    end
+
+    # Who to notify
+    #
+    # @return [<User>]
+    def users
+      resource_logic.users
+    end
+
+    private
+
+    attr_accessor :event
+
+    def resource_logic
+      return PostLogic.new(event: event) if event.post_id
+
+      raise 'The resource associated to the Event is not supported'
+    end
+  end
+end

app/services/push_notifications/event_notifier/post_logic.rb

@@ -0,0 +1,26 @@
+module PushNotifications
+  class EventNotifier
+    class PostLogic
+      def initialize(event:)
+        @event = event
+        @post = event.post
+      end
+
+      # Conditions for Post:
+      #
+      # We need to notify all the users that:
+      #  - are members of the Post's organization
+      #  - have a DeviceToken associated
+      #
+      # @return [<User>]
+      def users
+        organization = post.organization
+        User.joins(:device_tokens).where(id: organization.user_ids)
+      end
+
+      private
+
+      attr_accessor :event, :post
+    end
+  end
+end

spec/services/push_notifications/creator_spec.rb

@@ -0,0 +1,22 @@
+require 'spec_helper'
+
+RSpec.describe PushNotifications::Creator do
+  let(:user) { Fabricate.build(:user) }
+  let(:organization) { Fabricate(:organization) }
+  let(:post) { Fabricate(:post, organization: organization, user: user) }
+  let(:event) { Fabricate.build(:event, post: post, action: :created) }
+  let(:creator) { described_class.new(event: event) }
+
+  before do
+    organization.members.create(user: user)
+    Fabricate(:device_token, user: user, token: 'aloha')
+  end
+
+  describe '#create!' do
+    it 'creates as many PushNotification resources as needed' do
+      expect(PushNotification).to receive(:create!).once
+
+      creator.create!
+    end
+  end
+end

spec/services/push_notifications/event_notifier/post_logic_spec.rb

@@ -0,0 +1,36 @@
+require 'spec_helper'
+
+RSpec.describe ::PushNotifications::EventNotifier::PostLogic do
+  let(:user) { Fabricate.build(:user) }
+  let(:organization) { Fabricate(:organization) }
+  let(:post) { Fabricate(:post, organization: organization, user: user) }
+  let(:event) { Fabricate.build(:event, post: post, action: :created) }
+
+  describe '#users' do
+    context 'when a user pertains to the Post\'s organization' do
+      before { organization.members.create(user: user) }
+
+      context 'and the user has a DeviceToken associated' do
+        before { Fabricate(:device_token, user: user, token: 'aloha') }
+
+        it 'returns the user' do
+          expect(described_class.new(event: event).users).to include(user)
+        end
+      end
+
+      context 'but the user has no DeviceToken associated' do
+        it 'doesn\'t return the user' do
+          expect(described_class.new(event: event).users).to_not include(user)
+        end
+      end
+    end
+
+    context 'when a user doesn\'t pertain to the Post\'s organization' do
+      let(:other_user) { Fabricate.build(:user) }
+
+      it 'doesn\'t return the user' do
+        expect(described_class.new(event: event).users).to_not include(other_user)
+      end
+    end
+  end
+end

spec/services/push_notifications/event_notifier_spec.rb

@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+RSpec.describe PushNotifications::EventNotifier do
+  describe '#users' do
+    let(:user) { Fabricate.build(:user) }
+    let(:organization) { Fabricate(:organization) }
+
+    context 'when the given Event is associated to a Post' do
+      let(:post) { Fabricate(:post, organization: organization, user: user) }
+      let(:event) { Fabricate.build(:event, post: post, action: :created) }
+
+      it 'delegates #users to PostLogic' do
+        logic = instance_double(::PushNotifications::EventNotifier::PostLogic)
+        expect(::PushNotifications::EventNotifier::PostLogic).to receive(:new).and_return(logic)
+        expect(logic).to receive(:users)
+
+        described_class.new(event: event).users
+      end
+    end
+
+    context 'when the given Event is associated to a resource not supported' do
+      let(:event) { Fabricate.build(:event, action: :created) }
+
+      it 'raises an error' do
+        expect {
+          described_class.new(event: event).users
+        }.to raise_error('The resource associated to the Event is not supported')
+      end
+    end
+  end
+end