Add trending statuses (#17431)

* Add trending statuses

* Fix dangling items with stale scores in localized sets

* Various fixes and improvements

- Change approve_all/reject_all to approve_accounts/reject_accounts
- Change Trends::Query methods to not mutate the original query
- Change Trends::Query#skip to offset
- Change follow recommendations to be refreshed in a transaction

* Add tests for trending statuses filtering behaviour

* Fix not applying filtering scope in controller

app/models/trends.rb

@@ -13,15 +13,37 @@ module Trends
     @tags ||= Trends::Tags.new
   end
 
+  def self.statuses
+    @statuses ||= Trends::Statuses.new
+  end
+
+  def self.register!(status)
+    [links, tags, statuses].each { |trend_type| trend_type.register(status) }
+  end
+
   def self.refresh!
-    [links, tags].each(&:refresh)
+    [links, tags, statuses].each(&:refresh)
   end
 
   def self.request_review!
-    [links, tags].each(&:request_review) if enabled?
+    return unless enabled?
+
+    links_requiring_review    = links.request_review
+    tags_requiring_review     = tags.request_review
+    statuses_requiring_review = statuses.request_review
+
+    return if links_requiring_review.empty? && tags_requiring_review.empty? && statuses_requiring_review.empty?
+
+    User.staff.includes(:account).find_each do |user|
+      AdminMailer.new_trends(user.account, links_requiring_review, tags_requiring_review, statuses_requiring_review).deliver_later! if user.allows_trends_review_emails?
+    end
   end
 
   def self.enabled?
     Setting.trends
   end
+
+  def self.available_locales
+    @available_locales ||= I18n.available_locales.map { |locale| locale.to_s.split(/[_-]/).first }.uniq
+  end
 end