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

app/models/preview_card.rb

@@ -24,6 +24,11 @@
 #  embed_url                    :string           default(""), not null
 #  image_storage_schema_version :integer
 #  blurhash                     :string
+#  language                     :string
+#  max_score                    :float
+#  max_score_at                 :datetime
+#  trendable                    :boolean
+#  link_type                    :integer
 #
 
 class PreviewCard < ApplicationRecord
@@ -40,6 +45,7 @@ class PreviewCard < ApplicationRecord
   self.inheritance_column = false
 
   enum type: [:link, :photo, :video, :rich]
+  enum link_type: [:unknown, :article]
 
   has_and_belongs_to_many :statuses
 
@@ -54,6 +60,32 @@ class PreviewCard < ApplicationRecord
 
   before_save :extract_dimensions, if: :link?
 
+  def appropriate_for_trends?
+    link? && article? && title.present? && description.present? && image.present? && provider_name.present?
+  end
+
+  def domain
+    @domain ||= Addressable::URI.parse(url).normalized_host
+  end
+
+  def provider
+    @provider ||= PreviewCardProvider.matching_domain(domain)
+  end
+
+  def trendable?
+    if attributes['trendable'].nil?
+      provider&.trendable?
+    else
+      attributes['trendable']
+    end
+  end
+
+  def requires_review_notification?
+    attributes['trendable'].nil? && (provider.nil? || provider.requires_review_notification?)
+  end
+
+  attr_writer :provider
+
   def local?
     false
   end
@@ -69,11 +101,14 @@ class PreviewCard < ApplicationRecord
     save!
   end
 
+  def history
+    @history ||= Trends::History.new('links', id)
+  end
+
   class << self
     private
 
-    # rubocop:disable Naming/MethodParameterName
-    def image_styles(f)
+    def image_styles(file)
       styles = {
         original: {
           geometry: '400x400>',
@@ -83,10 +118,9 @@ class PreviewCard < ApplicationRecord
         },
       }
 
-      styles[:original][:format] = 'jpg' if f.instance.image_content_type == 'image/gif'
+      styles[:original][:format] = 'jpg' if file.instance.image_content_type == 'image/gif'
       styles
     end
-    # rubocop:enable Naming/MethodParameterName
   end
 
   private