Add trending links (#16917)

* Add trending links

* Add overriding specific links trendability

* Add link type to preview cards and only trend articles

Change trends review notifications from being sent every 5 minutes to being sent every 2 hours

Change threshold from 5 unique accounts to 15 unique accounts

* Fix tests

1 files changed, 35 insertions, 21 deletions

diff --git a/app/models/tag_filter.rb b/app/models/tag_filter.rb
index 85bfcbea5..ecdb52503 100644
--- a/app/models/tag_filter.rb
+++ b/app/models/tag_filter.rb
@@ -2,13 +2,8 @@
 
 class TagFilter
   KEYS = %i(
-    directory
-    reviewed
-    unreviewed
-    pending_review
-    popular
-    active
-    name
+    trending
+    status
   ).freeze
 
   attr_reader :params
@@ -18,7 +13,13 @@ class TagFilter
   end
 
   def results
-    scope = Tag.unscoped
+    scope = begin
+      if params[:status] == 'pending_review'
+        Tag.unscoped
+      else
+        trending_scope
+      end
+    end
 
     params.each do |key, value|
       next if key.to_s == 'page'
@@ -26,27 +27,40 @@ class TagFilter
       scope.merge!(scope_for(key, value.to_s.strip)) if value.present?
     end
 
-    scope.order(id: :desc)
+    scope
   end
 
   private
 
   def scope_for(key, value)
     case key.to_s
-    when 'reviewed'
-      Tag.reviewed.order(reviewed_at: :desc)
-    when 'unreviewed'
-      Tag.unreviewed
-    when 'pending_review'
-      Tag.pending_review.order(requested_review_at: :desc)
-    when 'popular'
-      Tag.order('max_score DESC NULLS LAST')
-    when 'active'
-      Tag.order('last_status_at DESC NULLS LAST')
-    when 'name'
-      Tag.matches_name(value)
+    when 'status'
+      status_scope(value)
     else
       raise "Unknown filter: #{key}"
     end
   end
+
+  def trending_scope
+    ids = Trends.tags.currently_trending_ids(false, -1)
+
+    if ids.empty?
+      Tag.none
+    else
+      Tag.joins("join unnest(array[#{ids.map(&:to_i).join(',')}]::integer[]) with ordinality as x (id, ordering) on tags.id = x.id").order('x.ordering')
+    end
+  end
+
+  def status_scope(value)
+    case value.to_s
+    when 'approved'
+      Tag.trendable
+    when 'rejected'
+      Tag.not_trendable
+    when 'pending_review'
+      Tag.pending_review
+    else
+      raise "Unknown status: #{value}"
+    end
+  end
 end