refactor chainable/footprint protected models to use inheritance

app/models/footprintable.rb

@@ -1,5 +1,34 @@
-module Footprintable
+# frozen_string_literal: true
+
+# SuperClass for models that are secured by chained footprints.
+class Footprintable < ApplicationRecord
+  self.abstract_class = true
+
   def self.columns_out_of_footprint
     []
   end
+
+  def check_footprint
+    footprint == compute_footprint
+  end
+
+  def chain_record(sort_on = 'id')
+    self.footprint = compute_footprint
+    save!
+    FootprintDebug.create!(
+      footprint: footprint,
+      data: FootprintService.footprint_data(self.class, self, sort_on),
+      klass: self.class.name
+    )
+  end
+
+  def debug_footprint
+    FootprintService.debug_footprint(self.class, self)
+  end
+
+  protected
+
+  def compute_footprint(sort_on = 'id')
+    FootprintService.compute_footprint(self.class, self, sort_on)
+  end
 end

app/models/history_value.rb

@@ -3,30 +3,14 @@
 require 'checksum'
 
 # Setting values, kept history of modifications
-class HistoryValue < ApplicationRecord
-  include Footprintable
-
+class HistoryValue < Footprintable
   belongs_to :setting
   belongs_to :invoicing_profile
 
   after_create :chain_record
 
   def chain_record
-    self.footprint = compute_footprint
-    save!
-    FootprintDebug.create!(
-      footprint: footprint,
-      data: FootprintService.footprint_data(HistoryValue, self, 'created_at'),
-      klass: HistoryValue.name
-    )
-  end
-
-  def check_footprint
-    footprint == compute_footprint
-  end
-
-  def debug_footprint
-    FootprintService.debug_footprint(HistoryValue, self)
+    super('created_at')
   end
 
   def user
@@ -36,6 +20,6 @@ class HistoryValue < ApplicationRecord
   private
 
   def compute_footprint
-    FootprintService.compute_footprint(HistoryValue, self, 'created_at')
+    super('created_at')
   end
 end

app/models/invoice.rb

@@ -4,8 +4,7 @@ require 'checksum'
 
 # Invoice correspond to a single purchase made by an user. This purchase may
 # include reservation(s) and/or a subscription
-class Invoice < ApplicationRecord
-  include Footprintable
+class Invoice < Footprintable
   include NotifyWith::NotificationAttachedObject
   require 'fileutils'
   scope :only_invoice, -> { where(type: nil) }
@@ -173,24 +172,10 @@ class Invoice < ApplicationRecord
     self.environment = Rails.env
   end
 
-  def chain_record
-    self.footprint = compute_footprint
-    save!
-    FootprintDebug.create!(
-      footprint: footprint,
-      data: FootprintService.footprint_data(Invoice, self),
-      klass: Invoice.name
-    )
-  end
-
   def check_footprint
     invoice_items.map(&:check_footprint).all? && footprint == compute_footprint
   end
 
-  def debug_footprint
-    FootprintService.debug_footprint(Invoice, self)
-  end
-
   def set_wallet_transaction(amount, transaction_id)
     raise InvalidFootprintError unless check_footprint
 
@@ -214,10 +199,6 @@ class Invoice < ApplicationRecord
     InvoiceWorker.perform_async(id, user&.subscription&.expired_at)
   end
 
-  def compute_footprint
-    FootprintService.compute_footprint(Invoice, self)
-  end
-
   def log_changes
     return if Rails.env.test?
     return unless changed?

app/models/invoice_item.rb

@@ -3,9 +3,7 @@
 require 'checksum'
 
 # A single line inside an invoice. Can be a subscription or a reservation
-class InvoiceItem < ApplicationRecord
-  include Footprintable
-
+class InvoiceItem < Footprintable
   belongs_to :invoice
   belongs_to :subscription
 
@@ -14,24 +12,6 @@ class InvoiceItem < ApplicationRecord
   after_create :chain_record
   after_update :log_changes
 
-  def chain_record
-    self.footprint = compute_footprint
-    save!
-    FootprintDebug.create!(
-      footprint: footprint,
-      data: FootprintService.footprint_data(InvoiceItem, self),
-      klass: InvoiceItem.name
-    )
-  end
-
-  def check_footprint
-    footprint == compute_footprint
-  end
-
-  def debug_footprint
-    FootprintService.debug_footprint(InvoiceItem, self)
-  end
-
   def amount_after_coupon
     # deduct coupon discount
     coupon_service = CouponService.new
@@ -53,10 +33,6 @@ class InvoiceItem < ApplicationRecord
 
   private
 
-  def compute_footprint
-    FootprintService.compute_footprint(InvoiceItem, self)
-  end
-
   def log_changes
     return if Rails.env.test?
     return unless changed?

app/models/payment_schedule.rb

@@ -2,9 +2,7 @@
 
 # PaymentSchedule is a way for members to pay something (especially a Subscription) with multiple payment,
 # staged on a long period rather than with a single payment
-class PaymentSchedule < ApplicationRecord
-  include Footprintable
-
+class PaymentSchedule < Footprintable
   belongs_to :scheduled, polymorphic: true
   belongs_to :wallet_transaction
   belongs_to :coupon
@@ -42,20 +40,6 @@ class PaymentSchedule < ApplicationRecord
     chain_record
   end
 
-  def chain_record
-    self.footprint = compute_footprint
-    save!
-    FootprintDebug.create!(
-      footprint: footprint,
-      data: FootprintService.footprint_data(PaymentSchedule, self),
-      klass: PaymentSchedule.name
-    )
-  end
-
-  def compute_footprint
-    FootprintService.compute_footprint(PaymentSchedule, self)
-  end
-
   def check_footprint
     payment_schedule_items.map(&:check_footprint).all? && footprint == compute_footprint
   end

app/models/payment_schedule_item.rb

@@ -1,31 +1,11 @@
 # frozen_string_literal: true
 
 # Represents a due date and the associated amount for a PaymentSchedule
-class PaymentScheduleItem < ApplicationRecord
-  include Footprintable
-
+class PaymentScheduleItem < Footprintable
   belongs_to :payment_schedule
   belongs_to :invoice
   after_create :chain_record
 
-  def chain_record
-    self.footprint = compute_footprint
-    save!
-    FootprintDebug.create!(
-      footprint: footprint,
-      data: FootprintService.footprint_data(PaymentScheduleItem, self),
-      klass: PaymentScheduleItem.name
-    )
-  end
-
-  def check_footprint
-    footprint == compute_footprint
-  end
-
-  def compute_footprint
-    FootprintService.compute_footprint(PaymentScheduleItem, self)
-  end
-
   def self.columns_out_of_footprint
     %w[invoice_id]
   end

app/services/footprint_service.rb

@@ -38,7 +38,7 @@ class FootprintService
   def self.debug_footprint(klass, item)
     columns = FootprintService.footprint_columns(klass)
     current = FootprintService.footprint_data(klass, item)
-    saved = FootprintDebug.find_by(footprint: item.footprint, klass: klass)
+    saved = FootprintDebug.find_by(footprint: item.footprint, klass: klass.name)
     puts "Debug footprint for #{klass} [ id: #{item.id} ]"
     puts '-----------------------------------------'
     puts "columns: [ #{columns.join(', ')} ]"