Simplify incineration

app/jobs/action_mailbox/incineration_job.rb

@@ -1,4 +1,4 @@
-class ActionMailbox::InboundEmail::IncinerationJob < ApplicationJob
+class ActionMailbox::IncinerationJob < ApplicationJob
   queue_as :action_mailbox_incineration
 
   def self.schedule(inbound_email)

app/models/action_mailbox/inbound_email.rb

@@ -19,4 +19,8 @@ class ActionMailbox::InboundEmail < ActiveRecord::Base
   def source
     @source ||= raw_email.download
   end
+
+  def processed?
+    delivered? || failed? || bounced?
+  end
 end

app/models/action_mailbox/inbound_email/incineratable.rb

@@ -2,27 +2,14 @@ module ActionMailbox::InboundEmail::Incineratable
   extend ActiveSupport::Concern
 
   included do
-    before_update :remember_to_incinerate_later
-    after_update_commit :incinerate_later, if: :incinerating_later?
+    after_update_commit :incinerate_later, if: -> { status_previously_changed? && processed? }
+  end
+
+  def incinerate_later
+    ActionMailbox::IncinerationJob.schedule self
   end
 
   def incinerate
     Incineration.new(self).run
   end
-
-  private
-    # TODO: Use enum change tracking once merged into Active Support
-    def remember_to_incinerate_later
-      if status_changed? && (delivered? || bounced? || failed?)
-        @incinerating_later = true
-      end
-    end
-
-    def incinerating_later?
-      @incinerating_later ||= false
-    end
-
-    def incinerate_later
-      ActionMailbox::InboundEmail::IncinerationJob.schedule(self)
-    end
 end

app/models/action_mailbox/inbound_email/incineratable/incineration.rb

@@ -4,7 +4,7 @@ class ActionMailbox::InboundEmail::Incineratable::Incineration
   end
 
   def run
-    @inbound_email.destroy if due? && processed?
+    @inbound_email.destroy! if due? && processed?
   end
 
   private
@@ -13,6 +13,6 @@ class ActionMailbox::InboundEmail::Incineratable::Incineration
     end
 
     def processed?
-      @inbound_email.delivered? || @inbound_email.bounced? || @inbound_email.failed?
+      @inbound_email.processed?
     end
 end

app/models/action_mailbox/inbound_email/routable.rb

@@ -2,7 +2,7 @@ module ActionMailbox::InboundEmail::Routable
   extend ActiveSupport::Concern
 
   included do
-    after_create_commit :route_later, if: ->(inbound_email) { inbound_email.pending? }
+    after_create_commit :route_later, if: :pending?
   end
 
   def route_later

test/unit/inbound_email/incineration_test.rb

@@ -4,7 +4,7 @@ class ActionMailbox::InboundEmail::IncinerationTest < ActiveSupport::TestCase
   test "incinerating 30 days after delivery" do
     freeze_time
 
-    assert_enqueued_with job: ActionMailbox::InboundEmail::IncinerationJob, at: 30.days.from_now do
+    assert_enqueued_with job: ActionMailbox::IncinerationJob, at: 30.days.from_now do
       create_inbound_email_from_fixture("welcome.eml").delivered!
     end
   end
@@ -12,7 +12,7 @@ class ActionMailbox::InboundEmail::IncinerationTest < ActiveSupport::TestCase
   test "incinerating 30 days after bounce" do
     freeze_time
 
-    assert_enqueued_with job: ActionMailbox::InboundEmail::IncinerationJob, at: 30.days.from_now do
+    assert_enqueued_with job: ActionMailbox::IncinerationJob, at: 30.days.from_now do
       create_inbound_email_from_fixture("welcome.eml").bounced!
     end
   end
@@ -20,7 +20,7 @@ class ActionMailbox::InboundEmail::IncinerationTest < ActiveSupport::TestCase
   test "incinerating 30 days after failure" do
     freeze_time
 
-    assert_enqueued_with job: ActionMailbox::InboundEmail::IncinerationJob, at: 30.days.from_now do
+    assert_enqueued_with job: ActionMailbox::IncinerationJob, at: 30.days.from_now do
       create_inbound_email_from_fixture("welcome.eml").failed!
     end
   end