update free places after cancel event reservation

app/models/event.rb

@@ -72,6 +72,15 @@ class Event < ActiveRecord::Base
   #   Reservation.where(reservable: self)
   # end
 
+  def update_nb_free_places
+    if nb_total_places.nil?
+      self.nb_free_places = nil
+    else
+      reserved_places = reservations.joins(:slots).where('slots.canceled_at': nil).map(&:total_booked_seats).inject(0) { |sum, t| sum + t }
+      self.nb_free_places = (nb_total_places - reserved_places)
+    end
+  end
+
   private
 
   def event_recurrence
@@ -141,13 +150,4 @@ class Event < ActiveRecord::Base
     end
     update_columns(recurrence_id: id)
   end
-
-  def update_nb_free_places
-    if nb_total_places.nil?
-      self.nb_free_places = nil
-    else
-      reserved_places = reservations.map(&:total_booked_seats).inject(0){ |sum, t| sum + t }
-      self.nb_free_places = (nb_total_places - reserved_places)
-    end
-  end
 end

app/models/reservation.rb

@@ -255,6 +255,13 @@ class Reservation < ActiveRecord::Base
     statistic_profile.user
   end
 
+  def update_event_nb_free_places
+    return unless reservable_type == 'Event'
+
+    reservable.update_nb_free_places
+    reservable.save!
+  end
+
   private
 
   def machine_not_already_reserved
@@ -280,8 +287,6 @@ class Reservation < ActiveRecord::Base
     errors.add(:training, 'already fully reserved') if Availability.find(slot.availability_id).completed?
   end
 
-  private
-
   def notify_member_create_reservation
     NotificationCenter.call type: 'notify_member_create_reservation',
                             receiver: user,
@@ -294,22 +299,6 @@ class Reservation < ActiveRecord::Base
                             attached_object: self
   end
 
-  def update_event_nb_free_places
-    if reservable_id_was.blank?
-      # simple reservation creation, we subtract the number of booked seats from the previous number
-      nb_free_places = reservable.nb_free_places - total_booked_seats
-    else
-      # reservation moved from another date (for recurring events)
-      seats = total_booked_seats
-
-      reservable_was = Event.find(reservable_id_was)
-      nb_free_places = reservable_was.nb_free_places + seats
-      reservable_was.update_columns(nb_free_places: nb_free_places)
-      nb_free_places = reservable.nb_free_places - seats
-    end
-    reservable.update_columns(nb_free_places: nb_free_places)
-  end
-
   def cart_total
     total = (invoice.invoice_items.map(&:amount).map(&:to_i).reduce(:+) or 0)
     if plan_id.present?

app/models/slot.rb

@@ -15,6 +15,7 @@ class Slot < ActiveRecord::Base
   after_update :notify_member_and_admin_slot_is_modified, if: :dates_were_modified?
 
   after_update :notify_member_and_admin_slot_is_canceled, if: :canceled?
+  after_update :update_event_nb_free_places, if: :canceled?
 
   # for backward compatibility
   def reservation
@@ -67,4 +68,11 @@ class Slot < ActiveRecord::Base
   def set_ex_start_end_dates_attrs
     update_columns(ex_start_at: start_at_was, ex_end_at: end_at_was)
   end
+
+  def update_event_nb_free_places
+    return unless reservation.reservable_type == 'Event'
+    raise NotImplementedError if reservations.count > 1
+
+    reservation.update_event_nb_free_places
+  end
 end