Add hashtag score for better sorting of autosuggestions (#11427)

* Add hashtag score for better sorting of autosuggestions

* Do not use `~<~` operator with no text_pattern_ops index

3 files changed, 10 insertions, 4 deletions

diff --git a/app/javascript/mastodon/reducers/compose.js b/app/javascript/mastodon/reducers/compose.js
index e683a9c1a..7b0cdd5a5 100644
--- a/app/javascript/mastodon/reducers/compose.js
+++ b/app/javascript/mastodon/reducers/compose.js
@@ -153,9 +153,9 @@ const sortHashtagsByUse = (state, tags) => {
     if (usedA === usedB) {
       return 0;
     } else if (usedA && !usedB) {
-      return 1;
-    } else {
       return -1;
+    } else {
+      return 1;
     }
   });
 };
diff --git a/app/models/tag.rb b/app/models/tag.rb
index 46e3a3ec0..a2d6078f4 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -7,6 +7,7 @@
 #  name       :string           default(""), not null
 #  created_at :datetime         not null
 #  updated_at :datetime         not null
+#  score      :integer
 #
 
 class Tag < ApplicationRecord
@@ -78,7 +79,7 @@ class Tag < ApplicationRecord
       pattern = sanitize_sql_like(normalize(term.strip)) + '%'
 
       Tag.where(arel_table[:name].lower.matches(pattern.mb_chars.downcase.to_s))
-         .order(:name)
+         .order(Arel.sql('length(name) ASC, score DESC, name ASC'))
          .limit(limit)
          .offset(offset)
     end
diff --git a/app/models/trending_tags.rb b/app/models/trending_tags.rb
index 148535c21..34a4abbc5 100644
--- a/app/models/trending_tags.rb
+++ b/app/models/trending_tags.rb
@@ -48,12 +48,17 @@ class TrendingTags
         redis.zrem(key, tag_id.to_s)
       else
         score = ((observed - expected)**2) / expected
-        redis.zadd(key, score, tag_id.to_s)
+        added = redis.zadd(key, score, tag_id.to_s)
+        bump_tag_score!(tag_id) if added == 1
       end
 
       redis.expire(key, EXPIRE_TRENDS_AFTER)
     end
 
+    def bump_tag_score!(tag_id)
+      Tag.where(id: tag_id).update_all('score = COALESCE(score, 0) + 1')
+    end
+
     def disallowed_hashtags
       return @disallowed_hashtags if defined?(@disallowed_hashtags)