FIX: show private message topic count on admin dashboard reports

app/models/admin_dashboard_data.rb

@@ -21,6 +21,7 @@ class AdminDashboardData
 
   PRIVATE_MESSAGE_REPORTS ||= [
     'user_to_user_private_messages',
+    'user_to_user_private_messages_with_replies',
     'system_private_messages',
     'notify_moderators_private_messages',
     'notify_user_private_messages',

app/models/report.rb

@@ -202,14 +202,20 @@ class Report
   # Private messages counts:
 
   def self.private_messages_report(report, topic_subtype)
-    basic_report_about report, Post, :private_messages_count_per_day, report.start_date, report.end_date, topic_subtype
-    add_counts report, Post.private_posts.with_topic_subtype(topic_subtype), 'posts.created_at'
+    basic_report_about report, Topic, :private_message_topics_count_per_day, report.start_date, report.end_date, topic_subtype
+    add_counts report, Topic.private_messages.with_subtype(topic_subtype), 'topics.created_at'
   end
 
   def self.report_user_to_user_private_messages(report)
     private_messages_report report, TopicSubtype.user_to_user
   end
 
+  def self.report_user_to_user_private_messages_with_replies(report)
+    topic_subtype = TopicSubtype.user_to_user
+    basic_report_about report, Post, :private_messages_count_per_day, report.start_date, report.end_date, topic_subtype
+    add_counts report, Post.private_posts.with_topic_subtype(topic_subtype), 'posts.created_at'
+  end
+
   def self.report_system_private_messages(report)
     private_messages_report report, TopicSubtype.system_message
   end

app/models/topic.rb

@@ -191,6 +191,8 @@ class Topic < ActiveRecord::Base
     where("topics.category_id IS NULL OR topics.category_id IN (SELECT id FROM categories WHERE #{condition[0]})", condition[1])
   }
 
+  scope :with_subtype, ->(subtype) { where('topics.subtype = ?', subtype) }
+
   attr_accessor :ignore_category_auto_close
   attr_accessor :skip_callbacks
 
@@ -1307,6 +1309,10 @@ SQL
     MiniSuffix.domain(URI.parse(URI.encode(self.featured_link)).hostname)
   end
 
+  def self.private_message_topics_count_per_day(start_date, end_date, topic_subtype)
+    private_messages.with_subtype(topic_subtype).where('topics.created_at >= ? AND topics.created_at <= ?', start_date, end_date).group('date(topics.created_at)').order('date(topics.created_at)').count
+  end
+
   private
 
   def update_category_topic_count_by(num)