DEV: Add backend support for unread and new topics list (#20293)

This commit adds backend support for a new topics list that combines both the current unread and new topics lists. We're going to experiment with this new list (name TBD) internally and decide if this feature is something that we want to fully build.

Internal topic: t/77234.

spec/lib/topic_query_spec.rb

@@ -1731,4 +1731,146 @@ RSpec.describe TopicQuery do
       end
     end
   end
+
+  describe "#new_and_unread_results" do
+    fab!(:unread_topic) { Fabricate(:post).topic }
+    fab!(:new_topic) { Fabricate(:post).topic }
+    fab!(:read_topic) { Fabricate(:post).topic }
+
+    before do
+      unread_post = Fabricate(:post, topic: unread_topic)
+      read_post = Fabricate(:post, topic: read_topic)
+
+      TopicUser.change(
+        user.id,
+        unread_topic.id,
+        notification_level: TopicUser.notification_levels[:tracking],
+      )
+      TopicUser.change(
+        user.id,
+        read_topic.id,
+        notification_level: TopicUser.notification_levels[:tracking],
+      )
+      TopicUser.update_last_read(user, unread_topic.id, unread_post.post_number - 1, 1, 1)
+      TopicUser.update_last_read(user, read_topic.id, read_post.post_number, 1, 1)
+    end
+
+    it "includes unread and new topics for the user" do
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+        new_topic.id,
+      )
+    end
+
+    it "doesn't include deleted topics" do
+      unread_topic.trash!
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        new_topic.id,
+      )
+    end
+
+    it "doesn't include muted topics with unread posts" do
+      TopicUser.change(
+        user.id,
+        unread_topic.id,
+        notification_level: TopicUser.notification_levels[:muted],
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        new_topic.id,
+      )
+    end
+
+    it "doesn't include muted new topics" do
+      TopicUser.change(
+        user.id,
+        new_topic.id,
+        notification_level: TopicUser.notification_levels[:muted],
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+      )
+    end
+
+    it "doesn't include new topics in muted category" do
+      CategoryUser.create!(
+        user_id: user.id,
+        category_id: new_topic.category.id,
+        notification_level: CategoryUser.notification_levels[:muted],
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+      )
+    end
+
+    it "includes unread and trakced topics even if they're in a muted category" do
+      new_topic.update!(category: Fabricate(:category))
+      CategoryUser.create!(
+        user_id: user.id,
+        category_id: unread_topic.category.id,
+        notification_level: CategoryUser.notification_levels[:muted],
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+        new_topic.id,
+      )
+    end
+
+    it "doesn't include new topics that have a muted tag(s)" do
+      SiteSetting.tagging_enabled = true
+
+      tag = Fabricate(:tag)
+      new_topic.tags << tag
+      new_topic.save!
+
+      TagUser.create!(
+        tag_id: tag.id,
+        user_id: user.id,
+        notification_level: NotificationLevels.all[:muted],
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+      )
+    end
+
+    it "includes unread and tracked topics even if they have a muted tag(s)" do
+      SiteSetting.tagging_enabled = true
+
+      tag = Fabricate(:tag)
+      unread_topic.tags << tag
+      unread_topic.save!
+
+      TagUser.create!(
+        tag_id: tag.id,
+        user_id: user.id,
+        notification_level: NotificationLevels.all[:muted],
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+        new_topic.id,
+      )
+    end
+
+    it "doesn't include topics in restricted categories that user cannot access" do
+      category = Fabricate(:category_with_definition)
+      group = Fabricate(:group)
+      category.set_permissions(group => :full)
+      category.save!
+
+      unread_topic.update!(category: category)
+      new_topic.update!(category: category)
+
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to be_blank
+    end
+
+    it "doesn't include dismissed topics" do
+      DismissedTopicUser.create!(
+        user_id: user.id,
+        topic_id: new_topic.id,
+        created_at: Time.zone.now,
+      )
+      expect(TopicQuery.new(user).new_and_unread_results.pluck(:id)).to contain_exactly(
+        unread_topic.id,
+      )
+    end
+  end
 end