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

1 files changed, 60 insertions, 0 deletions

diff --git a/app/models/trends/tag_filter.rb b/app/models/trends/tag_filter.rb
new file mode 100644
index 000000000..3b142efc4
--- /dev/null
+++ b/app/models/trends/tag_filter.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+class Trends::TagFilter
+  KEYS = %i(
+    trending
+    status
+  ).freeze
+
+  attr_reader :params
+
+  def initialize(params)
+    @params = params
+  end
+
+  def results
+    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'
+
+      scope.merge!(scope_for(key, value.to_s.strip)) if value.present?
+    end
+
+    scope
+  end
+
+  private
+
+  def scope_for(key, value)
+    case key.to_s
+    when 'status'
+      status_scope(value)
+    else
+      raise "Unknown filter: #{key}"
+    end
+  end
+
+  def trending_scope
+    Trends.tags.query.to_arel
+  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