Expire unused aliases and implications after 2 years of inactivity

app/logical/tag_relationship_retirement_service.rb

@@ -0,0 +1,67 @@
+module TagRelationshipRetirementService
+  THRESHOLD = 2.year
+
+  extend self
+
+  def forum_topic_title
+    return "Retired tag aliases & implications"
+  end
+
+  def forum_topic_body
+    return "This topic deals with tag relationships created two or more years ago that have not been used since. They will be retired. This topic will be updated as an automated system retires expired relationships."
+  end
+
+  def dry_run
+    [TagAlias, TagImplication].each do |model|
+      each_candidate(model) do |rel|
+        puts "#{rel.relationship} #{rel.antecedent_name} -> #{rel.consequent_name} retired"
+      end
+    end
+  end
+
+  def forum_topic
+    topic = ForumTopic.where(title: forum_topic_title).first
+    if topic.nil?
+      topic = CurrentUser.as_system do
+        ForumTopic.create(title: forum_topic_title, category_id: 1, original_post_attributes: {body: forum_topic_body})
+      end
+    end
+    return topic
+  end
+
+  def find_and_retire!
+    messages = []
+
+    [TagAlias, TagImplication].each do |model|
+      each_candidate(model) do |rel|
+        rel.update(status: "retired")
+        messages << rel.retirement_message
+      end
+    end
+
+    updater = ForumUpdater.new(forum_topic)
+    updater.update(messages.sort.join("\n"))
+  end
+
+  def each_candidate(model)
+    model.active.where("created_at < ?", THRESHOLD.ago).find_each do |rel|
+      if is_unused?(rel.consequent_name)
+        yield(rel)
+      end
+    end
+
+    # model.active.where("created_at < ?", SMALL_THRESHOLD.ago).find_each do |rel|
+    #   if is_underused?(rel.consequent_name)
+    #     yield(rel)
+    #   end
+    # end
+  end
+
+  def is_underused?(name)
+    (Tag.find_by_name(name).try(:post_count) || 0) < COUNT_THRESHOLD
+  end
+
+  def is_unused?(name)
+    return !Post.tag_match("status:any #{name}").where("created_at > ?", THRESHOLD.ago).exists?
+  end
+end