FEATURE: add a rake task to recalculate user stats post_count and topic_count

lib/tasks/import.rake

@@ -226,6 +226,9 @@ end
 def update_user_stats
   log "Updating user stats..."
 
+  # TODO: topic_count is counting all topics you replied in as if you started the topic.
+  # TODO: post_count is counting first posts.
+  # TODO: topic_reply_count is never used, and is counting PMs here.
   DB.exec <<-SQL
     WITH X AS (
       SELECT p.user_id

lib/tasks/users.rake

@@ -80,6 +80,61 @@ task "users:update_posts", [:old_username, :current_username] => [:environment]
   puts "", "Username updated!", ""
 end
 
+desc 'Recalculate post and topic counts in user stats'
+task 'users:recalculate_post_counts' => :environment do
+  puts '', 'Updating user stats...'
+
+  filter_public_posts_and_topics = <<~SQL
+    p.deleted_at IS NULL
+     AND NOT COALESCE(p.hidden, 't')
+     AND p.post_type = 1
+     AND t.deleted_at IS NULL
+     AND COALESCE(t.visible, 't')
+     AND t.archetype <> 'private_message'
+     AND p.user_id > 0
+  SQL
+
+  puts 'post counts...'
+
+  # all public replies
+  DB.exec <<~SQL
+    WITH X AS (
+      SELECT p.user_id, COUNT(p.id) post_count
+    FROM posts p
+    JOIN topics t ON t.id = p.topic_id
+   WHERE #{filter_public_posts_and_topics}
+     AND p.post_number > 1
+GROUP BY p.user_id
+    )
+    UPDATE user_stats
+       SET post_count = X.post_count
+      FROM X
+     WHERE user_stats.user_id = X.user_id
+       AND user_stats.post_count <> X.post_count
+  SQL
+
+  puts 'topic counts...'
+
+  # public topics
+  DB.exec <<~SQL
+    WITH X AS (
+      SELECT p.user_id, COUNT(p.id) topic_count
+    FROM posts p
+    JOIN topics t ON t.id = p.topic_id
+   WHERE #{filter_public_posts_and_topics}
+     AND p.post_number = 1
+GROUP BY p.user_id
+    )
+    UPDATE user_stats
+       SET topic_count = X.topic_count
+      FROM X
+     WHERE user_stats.user_id = X.user_id
+       AND user_stats.topic_count <> X.topic_count
+  SQL
+
+  puts 'Done!', ''
+end
+
 def find_user(username)
   user = User.find_by_username(username)