Log whenever Form Upload Flow prefill data is changed

modules/simple_forms_api/app/controllers/simple_forms_api/v1/scanned_form_uploads_controller.rb

@@ -8,6 +8,8 @@ module V1
     class ScannedFormUploadsController < ApplicationController
       def submit
         Datadog::Tracing.active_trace&.set_tag('form_id', params[:form_number])
+        check_for_changes
+
         render json: upload_response
       end
 
@@ -98,6 +100,16 @@ def perform_pdf_upload(location, file_path, metadata)
           upload_url: location
         )
       end
+
+      def check_for_changes
+        in_progress_form = InProgressForm.form_for_user('FORM-UPLOAD-FLOW', @current_user)
+        if in_progress_form
+          prefill_data_service = SimpleFormsApi::PrefillDataService.new(prefill_data: in_progress_form.form_data,
+                                                                        form_data: params[:form_data],
+                                                                        form_id: params[:form_number])
+          prefill_data_service.check_for_changes
+        end
+      end
     end
   end
 end

modules/simple_forms_api/app/services/simple_forms_api/prefill_data_service.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module SimpleFormsApi
+  class PrefillDataService
+    attr_reader :prefill_data, :form_data, :form_id
+
+    def initialize(prefill_data:, form_data:, form_id:)
+      @prefill_data = JSON.parse(prefill_data)
+      @form_data = form_data
+      @form_id = form_id
+    end
+
+    def check_for_changes
+      changed_fields = []
+      changed_fields << 'first_name' if prefill_data.dig('full_name', 'first') != form_data.dig('full_name', 'first')
+      changed_fields << 'last_name' if prefill_data.dig('full_name', 'last') != form_data.dig('full_name', 'last')
+      changed_fields << 'postal_code' if prefill_data.dig('address', 'postal_code') != form_data['postal_code']
+      changed_fields << 'ssn' if prefill_data.dig('veteran', 'ssn') != form_data.dig('id_number', 'ssn')
+      changed_fields << 'email' if prefill_data['email'] != form_data['email']
+
+      changed_fields.each do |field|
+        Rails.logger.info('Simple forms api - Form Upload Flow changed data', { field:, form_id: })
+      end
+    end
+  end
+end

modules/simple_forms_api/spec/requests/simple_forms_api/v1/scanned_form_uploads_spec.rb

@@ -52,6 +52,28 @@
 
       expect(response).to have_http_status(:ok)
     end
+
+    it 'checks if the prefill data has been changed' do
+      form_number = '21-0779'
+      prefill_data = double
+      prefill_data_service = double
+      in_progress_form = double(form_data: prefill_data)
+
+      allow(SimpleFormsApi::PrefillDataService).to receive(:new).with(
+        prefill_data:,
+        form_data: hash_including(:email),
+        form_id: form_number
+      ).and_return(prefill_data_service)
+      allow(InProgressForm).to receive(:form_for_user).with('FORM-UPLOAD-FLOW',
+                                                            anything).and_return(in_progress_form)
+
+      expect(prefill_data_service).to receive(:check_for_changes)
+
+      post '/simple_forms_api/v1/submit_scanned_form',
+           params: { form_number:, confirmation_code:, form_data: { email: 'fake-email' } }
+
+      expect(response).to have_http_status(:ok)
+    end
   end
 
   describe '#upload_scanned_form' do

modules/simple_forms_api/spec/services/prefill_data_service_spec.rb

@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require SimpleFormsApi::Engine.root.join('spec', 'spec_helper.rb')
+
+describe SimpleFormsApi::PrefillDataService do
+  describe '#check_for_changes' do
+    let(:form_id) { '21-0779' }
+    let(:rails_logger) { double }
+    let(:prefill_data) do
+      {
+        'full_name' => {
+          'first' => 'fake-first-name',
+          'last' => 'fake-last-name'
+        },
+        'address' => {
+          'postal_code' => '12345'
+        },
+        'veteran' => {
+          'ssn' => 'fake-ssn'
+        },
+        'email' => 'fake-email'
+      }
+    end
+    let(:form_data) do
+      {
+        'full_name' => {
+          'first' => 'fake-first-name',
+          'last' => 'fake-last-name'
+        },
+        'postal_code' => '12345',
+        'id_number' => {
+          'ssn' => 'fake-ssn'
+        },
+        'email' => 'fake-email'
+      }
+    end
+    let(:prefill_data_service) do
+      SimpleFormsApi::PrefillDataService.new(
+        prefill_data: prefill_data.to_json, form_data: modified_form_data,
+        form_id:
+      )
+    end
+
+    before { allow(Rails).to receive(:logger).and_return(rails_logger) }
+
+    context 'first_name does not match' do
+      let(:modified_form_data) do
+        form_data.merge({ 'full_name' => {
+                          'first' => 'new-first-name',
+                          'last' => 'fake-last-name'
+                        } })
+      end
+
+      it 'logs the first_name change' do
+        expect(rails_logger).to receive(:info).with(anything, { field: 'first_name', form_id: })
+
+        prefill_data_service.check_for_changes
+      end
+    end
+
+    context 'last_name does not match' do
+      let(:modified_form_data) do
+        form_data.merge({ 'full_name' => {
+                          'first' => 'fake-first-name',
+                          'last' => 'new-last-name'
+                        } })
+      end
+
+      it 'logs the last_name change' do
+        expect(rails_logger).to receive(:info).with(anything, { field: 'last_name', form_id: })
+
+        prefill_data_service.check_for_changes
+      end
+    end
+
+    context 'postal_code does not match' do
+      let(:modified_form_data) do
+        form_data.merge({ 'postal_code' => '67890' })
+      end
+
+      it 'logs the postal_code change' do
+        expect(rails_logger).to receive(:info).with(anything, { field: 'postal_code', form_id: })
+
+        prefill_data_service.check_for_changes
+      end
+    end
+
+    context 'ssn does not match' do
+      let(:modified_form_data) do
+        form_data.merge({ 'id_number' => { 'ssn' => 'new-ssn' } })
+      end
+
+      it 'logs the ssn change' do
+        expect(rails_logger).to receive(:info).with(anything, { field: 'ssn', form_id: })
+
+        prefill_data_service.check_for_changes
+      end
+    end
+
+    context 'email does not match' do
+      let(:modified_form_data) do
+        form_data.merge({ 'email' => 'new-email' })
+      end
+
+      it 'logs the email change' do
+        expect(rails_logger).to receive(:info).with(anything, { field: 'email', form_id: })
+
+        prefill_data_service.check_for_changes
+      end
+    end
+  end
+end