Refactor and harmonise metadata for invalid letters with those sent from admin app

app/celery/letters_pdf_tasks.py

@@ -5,7 +5,6 @@ from uuid import UUID
 from hashlib import sha512
 from base64 import urlsafe_b64encode
 
-from PyPDF2.utils import PdfReadError
 from botocore.exceptions import ClientError as BotoClientError
 from flask import current_app
 from requests import (
@@ -30,6 +29,7 @@ from app.dao.notifications_dao import (
 from app.errors import VirusScanError
 from app.letters.utils import (
     copy_redaction_failed_pdf,
+    get_billable_units_for_letter_page_count,
     get_reference_from_filename,
     get_folder_name,
     upload_letter_pdf,
@@ -38,7 +38,6 @@ from app.letters.utils import (
     move_scan_to_invalid_pdf_bucket,
     move_error_pdf_to_scan_bucket,
     get_file_names_from_error_bucket,
-    get_page_count,
 )
 from app.models import (
     KEY_TYPE_TEST,
@@ -209,17 +208,8 @@ def process_virus_scan_passed(self, filename):
     scan_pdf_object = s3.get_s3_object(current_app.config['LETTERS_SCAN_BUCKET_NAME'], filename)
     old_pdf = scan_pdf_object.get()['Body'].read()
 
-    try:
-        billable_units = get_page_count(old_pdf)
-    except PdfReadError:
-        current_app.logger.exception(msg='Invalid PDF received for notification_id: {}'.format(notification.id))
-        _move_invalid_letter_and_update_status(
-            notification=notification, filename=filename, scan_pdf_object=scan_pdf_object
-        )
-        return
-
-    sanitise_response = _sanitise_precompiled_pdf(self, notification, old_pdf)
-    if sanitise_response["message"]:  # is response without message attribute possible now? I think not?
+    sanitise_response, result = _sanitise_precompiled_pdf(self, notification, old_pdf)
+    if result == "validation_failed":
         new_pdf = None
     else:
         new_pdf = base64.b64decode(sanitise_response["file"].encode())
@@ -231,6 +221,8 @@ def process_virus_scan_passed(self, filename):
             )
             copy_redaction_failed_pdf(filename)
 
+    billable_units = get_billable_units_for_letter_page_count(sanitise_response.get("page_count"))
+
     # TODO: Remove this once CYSP update their template to not cross over the margins
     if notification.service_id == UUID('fe44178f-3b45-4625-9f85-2264a36dd9ec'):  # CYSP
         # Check your state pension submit letters with good addresses and notify tags, so just use their supplied pdf
@@ -322,19 +314,19 @@ def _sanitise_precompiled_pdf(self, notification, precompiled_pdf):
                      'Notification-ID': str(notification.id)}
         )
         response.raise_for_status()
-        return response.json()
+        return response.json(), "validation_passed"
     except RequestException as ex:
         if ex.response is not None and ex.response.status_code == 400:
             message = "sanitise_precompiled_pdf validation error for notification: {}. ".format(notification.id)
-            if "message" in response.json():
+            if response.json().get("message"):
                 message += response.json()["message"]
-            if "invalid_pages" in response.json():
-                message += (" on pages: " + ", ".join(map(str, response.json()["invalid_pages"])))
+                if response.json().get("invalid_pages"):
+                    message += (" on pages: " + ", ".join(map(str, response.json()["invalid_pages"])))
 
             current_app.logger.info(
                 message
             )
-            return response.json()
+            return response.json(), "validation_failed"
 
         try:
             current_app.logger.exception(