New endpoint to insert new service reply to email address and update existing one.

app/dao/service_email_reply_to_dao.py

@@ -9,7 +9,7 @@ def dao_get_reply_to_by_service_id(service_id):
         ServiceEmailReplyTo
     ).filter(
         ServiceEmailReplyTo.service_id == service_id
-    ).all()
+    ).order_by(ServiceEmailReplyTo.created_at).all()
     return reply_to
 
 
@@ -37,3 +37,57 @@ def dao_create_reply_to_email_address(reply_to_email):
 @transactional
 def dao_update_reply_to_email(reply_to):
     db.session.add(reply_to)
+
+
+@transactional
+def add_reply_to_email_address_for_service(service_id, email_address, is_default=True):
+    old_default = _get_existing_default(service_id)
+    if is_default:
+        _reset_old_default_to_false(old_default)
+    else:
+        _raise_when_no_default(old_default)
+
+    new_reply_to = ServiceEmailReplyTo(service_id=service_id, email_address=email_address, is_default=is_default)
+    db.session.add(new_reply_to)
+    return new_reply_to
+
+
+@transactional
+def update_reply_to_email_address(service_id, reply_to_id, email_address, is_default=True):
+    old_default = _get_existing_default(service_id)
+    if is_default:
+        _reset_old_default_to_false(old_default)
+    else:
+        if old_default.id == reply_to_id:
+            raise InvalidRequest("You must have at least one reply to email address as the default.", 400)
+
+    reply_to_update = ServiceEmailReplyTo.query.get(reply_to_id)
+    reply_to_update.email_address = email_address
+    reply_to_update.is_default = is_default
+    db.session.add(reply_to_update)
+    return reply_to_update
+
+
+def _get_existing_default(service_id):
+    existing_reply_to = dao_get_reply_to_by_service_id(service_id=service_id)
+    if existing_reply_to:
+        old_default = [x for x in existing_reply_to if x.is_default]
+        if len(old_default) == 1:
+            return old_default[0]
+        else:
+            # is this check necessary
+            raise InvalidRequest(
+                "There should only be one default reply to email for each service. Service {} has {}".format(
+                    service_id, len(old_default)))
+
+
+def _reset_old_default_to_false(old_default):
+    if old_default:
+        old_default.is_default = False
+        db.session.add(old_default)
+
+
+def _raise_when_no_default(old_default):
+    # check that the update is not updating the only default to false
+    if not old_default:
+        raise InvalidRequest("You must have at least one reply to email address as the default.", 400)