From 75441e063a3a4c3e40b52f2936e5dbe113e5fee0 Mon Sep 17 00:00:00 2001
From: David Battersby <info@davidbattersby.com>
Date: Fri, 20 Oct 2023 17:56:50 +0800
Subject: [PATCH] DEV: create new_post_moved event trigger when moving posts
 (#24005)

This change adds a new event trigger (new_post_moved) when the first post in a topic is moved to a new topic.

Plugins that listen for the new_post_moved event now have an easy way to update old data based on the post id.
---
 app/models/post_mover.rb       |  1 +
 spec/models/post_mover_spec.rb | 40 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/app/models/post_mover.rb b/app/models/post_mover.rb
index cfa1720318c..45e78acf350 100644
--- a/app/models/post_mover.rb
+++ b/app/models/post_mover.rb
@@ -277,6 +277,7 @@ class PostMover
     new_post.custom_fields = post.custom_fields
     new_post.save_custom_fields
 
+    DiscourseEvent.trigger(:first_post_moved, new_post, post)
     DiscourseEvent.trigger(:post_moved, new_post, original_topic.id)
 
     # we don't want to keep the old topic's OP bookmarked when we are
diff --git a/spec/models/post_mover_spec.rb b/spec/models/post_mover_spec.rb
index 28186efd54d..1656d2db870 100644
--- a/spec/models/post_mover_spec.rb
+++ b/spec/models/post_mover_spec.rb
@@ -2463,5 +2463,45 @@ RSpec.describe PostMover do
         end
       end
     end
+
+    context "with event trigger" do
+      fab!(:topic_1) { Fabricate(:topic) }
+      fab!(:topic_2) { Fabricate(:topic) }
+      fab!(:post_1) { Fabricate(:post, topic: topic_1) }
+      fab!(:post_2) { Fabricate(:post, topic: topic_1) }
+
+      it "receives 2 post moved event triggers for the first post" do
+        post_mover = PostMover.new(topic_1, Discourse.system_user, [post_1.id])
+        events = DiscourseEvent.track_events { post_mover.to_topic(topic_2.id) }
+        filtered_events =
+          events.filter { |e| %i[first_post_moved post_moved].include? e[:event_name] }
+
+        expect(filtered_events.size).to eq(2)
+      end
+
+      it "uses first_post_moved trigger for first post" do
+        post_mover = PostMover.new(topic_1, Discourse.system_user, [post_1.id])
+        events = DiscourseEvent.track_events(:first_post_moved) { post_mover.to_topic(topic_2.id) }
+        expect(events.size).to eq(1)
+
+        new_post = Post.find_by(topic_id: topic_2.id, post_number: 1)
+
+        event = events.first
+        expect(event[:event_name]).to eq(:first_post_moved)
+        expect(event[:params][0]).to eq(new_post)
+        expect(event[:params][1]).to eq(post_1)
+      end
+
+      it "uses post_moved trigger for other posts" do
+        post_mover = PostMover.new(topic_1, Discourse.system_user, [post_2.id])
+        events = DiscourseEvent.track_events(:post_moved) { post_mover.to_topic(topic_2.id) }
+        expect(events.size).to eq(1)
+
+        event = events.first
+        expect(event[:event_name]).to eq(:post_moved)
+        expect(event[:params][0]).to eq(post_2)
+        expect(event[:params][1]).to eq(topic_1.id)
+      end
+    end
   end
 end