tags: remove Tag.trending method.

This is used for the frontpage taglist when popular searches are
disabled. This isn't used in production and there's no need for it in
development.

app/models/tag.rb

@@ -205,45 +205,6 @@ class Tag < ApplicationRecord
     end
   end
 
-  module StatisticsMethods
-    def trending_count_limit
-      10
-    end
-
-    def trending
-      Cache.get("popular-tags-v3", 1.hour) do
-        CurrentUser.scoped(User.admins.first, "127.0.0.1") do
-          n = 24
-          counts = {}
-
-          while counts.empty? && n < 1000
-            tag_strings = Post.select_values_sql("select tag_string from posts where created_at >= ?", n.hours.ago)
-            tag_strings.each do |tag_string|
-              tag_string.split.each do |tag|
-                counts[tag] ||= 0
-                counts[tag] += 1
-              end
-            end
-            n *= 2
-          end
-
-          counts = counts.to_a.select {|x| x[1] > trending_count_limit}
-          counts = counts.map do |tag_name, recent_count|
-            tag = Tag.find_or_create_by_name(tag_name)
-            if tag.category == Tag.categories.artist
-              # we're not interested in artists in the trending list
-              [tag_name, 0]
-            else
-              [tag_name, recent_count.to_f / tag.post_count.to_f]
-            end
-          end
-
-          counts.sort_by {|x| -x[1]}.slice(0, 25).map(&:first)
-        end
-      end
-    end
-  end
-
   concerning :NameMethods do
     def unqualified_name
       name.gsub(/_\(.*\)\z/, "").tr("_", " ")
@@ -956,7 +917,6 @@ class Tag < ApplicationRecord
   include ApiMethods
   include CountMethods
   include CategoryMethods
-  extend StatisticsMethods
   extend ParseMethods
   extend SearchMethods
 end

app/presenters/post_set_presenters/post.rb

@@ -35,7 +35,7 @@ module PostSetPresenters
       if PopularSearchService.enabled?
         PopularSearchService.new(Date.today).tags
       else
-        Tag.trending
+        frequent_tags
       end
     end
 

test/unit/tag_test.rb

@@ -12,24 +12,6 @@ class TagTest < ActiveSupport::TestCase
     CurrentUser.ip_addr = nil
   end
 
-  context ".trending" do
-    setup do
-      Tag.stubs(:trending_count_limit).returns(0)
-
-      travel_to(1.week.ago) do
-        FactoryBot.create(:post, :tag_string => "aaa")
-        FactoryBot.create(:post, :tag_string => "bbb")
-      end
-
-      FactoryBot.create(:post, :tag_string => "bbb")
-      FactoryBot.create(:post, :tag_string => "ccc")
-    end
-
-    should "order the results by the total post count" do
-      assert_equal(["ccc", "bbb"], Tag.trending)
-    end
-  end
-
   context "A tag category fetcher" do
     should "fetch for a single tag" do
       FactoryBot.create(:artist_tag, :name => "test")