Add scope to Submission by version and date

This scope orders a list of submissions by their form's udpated_at,
which is used as a proxy for its version, and then the submission date.
The intention is to use this in the CSV generation for submission
batches, where we'll need to maintain the order that submissions were
made, but keep them in version clusters

Co-authored-by: Stephen Daly <stephen.daly@digital.cabinet-office.gov.uk>

Author: SamJamCul

app/models/submission.rb

@@ -6,7 +6,11 @@ class Submission < ApplicationRecord
     start_time = date.in_time_zone(TimeZoneUtils.submission_time_zone).beginning_of_day
     end_time = start_time.end_of_day
 
-    where(form_id:, created_at: start_time..end_time, mode: mode).order(created_at: :desc)
+    where(form_id:, created_at: start_time..end_time, mode: mode)
+  }
+
+  scope :ordered_by_form_version_and_date, lambda {
+    order(Arel.sql("(form_document->>'updated_at')::timestamptz ASC, created_at ASC"))
   }
 
   delegate :preview?, to: :mode_object

spec/models/submission_spec.rb

@@ -45,6 +45,22 @@
         end
       end
     end
+
+    describe ".ordered_by_form_version_and_date" do
+      let(:first_form_version) { create :v2_form_document, updated_at: Time.utc(2022, 6, 1, 12, 0, 0) }
+      let(:second_form_version) { create :v2_form_document, updated_at: Time.utc(2022, 12, 1, 12, 0, 0) }
+
+      before do
+        create :submission, form_document: second_form_version, created_at: Time.utc(2022, 12, 1, 21, 0, 0), reference: "fourth_submission"
+        create :submission, form_document: first_form_version, created_at: Time.utc(2022, 12, 1, 15, 0, 0), reference: "third_submission"
+        create :submission, form_document: second_form_version, created_at: Time.utc(2022, 12, 1, 13, 0, 0), reference: "second_submission"
+        create :submission, form_document: first_form_version, created_at: Time.utc(2022, 12, 1, 9, 0, 0), reference: "first_submission"
+      end
+
+      it "returns the submissions in order" do
+        expect(described_class.all.ordered_by_form_version_and_date.pluck(:reference)).to eq(%w[first_submission third_submission second_submission fourth_submission])
+      end
+    end
   end
 
   describe "#sent?" do