Simplify putting letters in right postage folders

app/celery/letters_pdf_tasks.py

@@ -42,6 +42,7 @@ from app.models import (
     NOTIFICATION_TECHNICAL_FAILURE,
     NOTIFICATION_VALIDATION_FAILED,
     NOTIFICATION_VIRUS_SCAN_FAILED,
+    POSTAGE_TYPES,
     RESOLVE_POSTAGE_FOR_FILE_NAME
 )
 from app.cronitor import cronitor
@@ -135,21 +136,18 @@ def collate_letter_pdfs_to_be_sent():
     print_run_deadline = print_run_date.replace(
         hour=17, minute=30, second=0, microsecond=0
     )
+    for postage in POSTAGE_TYPES:
+        letters_to_print = get_key_and_size_of_letters_to_be_sent_to_print(print_run_deadline, postage)
 
-    letters_to_print = get_key_and_size_of_letters_to_be_sent_to_print(print_run_deadline)
-
-    for zip_folder, letters_list in letters_to_print.items():
-        i = 0
-        for letters in group_letters(letters_list):
-            i += 1
+        for i, letters in enumerate(group_letters(letters_to_print)):
             filenames = [letter['Key'] for letter in letters]
 
             hash = urlsafe_b64encode(sha512(''.join(filenames).encode()).digest())[:20].decode()
             # eg NOTIFY.2018-12-31.001.Wjrui5nAvObjPd-3GEL-.ZIP
             dvla_filename = 'NOTIFY.{date}.{postage}.{num:03}.{hash}.ZIP'.format(
                 date=print_run_deadline.strftime("%Y-%m-%d"),
-                postage=RESOLVE_POSTAGE_FOR_FILE_NAME[zip_folder],
-                num=i,
+                postage=RESOLVE_POSTAGE_FOR_FILE_NAME[postage],
+                num=i + 1,
                 hash=hash
             )
 
@@ -171,9 +169,9 @@ def collate_letter_pdfs_to_be_sent():
             )
 
 
-def get_key_and_size_of_letters_to_be_sent_to_print(print_run_deadline):
-    letters_awaiting_sending = dao_get_letters_to_be_printed(print_run_deadline)
-    letter_pdfs = {"first": [], "second": [], "europe": [], "rest-of-world": []}
+def get_key_and_size_of_letters_to_be_sent_to_print(print_run_deadline, postage):
+    letters_awaiting_sending = dao_get_letters_to_be_printed(print_run_deadline, postage)
+    letter_pdfs = []
     for letter in letters_awaiting_sending:
         try:
             letter_file_name = get_letter_pdf_filename(
@@ -183,7 +181,7 @@ def get_key_and_size_of_letters_to_be_sent_to_print(print_run_deadline):
                 postage=letter.postage
             )
             letter_head = s3.head_s3_object(current_app.config['LETTERS_PDF_BUCKET_NAME'], letter_file_name)
-            letter_pdfs[letter.postage].append({"Key": letter_file_name, "Size": letter_head['ContentLength']})
+            letter_pdfs.append({"Key": letter_file_name, "Size": letter_head['ContentLength']})
         except BotoClientError as e:
             current_app.logger.exception(
                 f"Error getting letter from bucket for notification: {letter.id} with reference: {letter.reference}", e)

app/dao/notifications_dao.py

@@ -740,7 +740,7 @@ def notifications_not_yet_sent(should_be_sending_after_seconds, notification_typ
     return notifications
 
 
-def dao_get_letters_to_be_printed(print_run_deadline):
+def dao_get_letters_to_be_printed(print_run_deadline, postage):
     """
     Return all letters created before the print run deadline that have not yet been sent
     """
@@ -748,7 +748,8 @@ def dao_get_letters_to_be_printed(print_run_deadline):
         Notification.created_at < convert_bst_to_utc(print_run_deadline),
         Notification.notification_type == LETTER_TYPE,
         Notification.status == NOTIFICATION_CREATED,
-        Notification.key_type == KEY_TYPE_NORMAL
+        Notification.key_type == KEY_TYPE_NORMAL,
+        Notification.postage == postage,
     ).order_by(
         Notification.created_at
     ).all()