DRY-up and enforce kwargs for most events

For most events this makes the purpose of each argument clearer at
the point the event is called. It's still worth having a function
for each event type, as this abstracts knowledge of the event label.
Using a schema approach will make adding new events easier.

In the next commit we'll DRY-up the duplication in the tests as well.

app/event_handlers.py

@@ -2,94 +2,62 @@ from flask import request
 
 from app import events_api_client
 
+EVENT_SCHEMAS = {
+    "sucessful_login": {"user_id"},
+    "update_user_email": {"user_id", "updated_by_id", "original_email_address", "new_email_address"},
+    "update_user_mobile_number": {"user_id", "updated_by_id", "original_mobile_number", "new_mobile_number"},
+    "remove_user_from_service": {"user_id", "removed_by_id", "service_id"},
+    "add_user_to_service": {"user_id", "invited_by_id", "service_id"},
+    "archive_user": {"user_id", "archived_by_id"},
+    "change_broadcast_account_type": {"service_id", "changed_by_id", "service_mode", "broadcast_channel", "provider_restriction"},  # noqa: E501 (length)
+    "archive_service": {"service_id", "archived_by_id"},
+    "suspend_service": {"service_id", "suspended_by_id"},
+}
+
 
 def on_user_logged_in(_sender, user):
     _send_event('sucessful_login', user_id=user.id)
 
 
-def create_email_change_event(user_id, updated_by_id, original_email_address, new_email_address):
-    _send_event(
-        'update_user_email',
-        user_id=user_id,
-        updated_by_id=updated_by_id,
-        original_email_address=original_email_address,
-        new_email_address=new_email_address)
+def create_email_change_event(**kwargs):
+    _send_event('update_user_email', **kwargs)
 
 
-def create_mobile_number_change_event(user_id, updated_by_id, original_mobile_number, new_mobile_number):
-    _send_event(
-        'update_user_mobile_number',
-        user_id=user_id,
-        updated_by_id=updated_by_id,
-        original_mobile_number=original_mobile_number,
-        new_mobile_number=new_mobile_number)
+def create_mobile_number_change_event(**kwargs):
+    _send_event('update_user_mobile_number', **kwargs)
 
 
-def create_remove_user_from_service_event(user_id, removed_by_id, service_id):
-    _send_event(
-        'remove_user_from_service',
-        user_id=user_id,
-        removed_by_id=removed_by_id,
-        service_id=service_id
-    )
+def create_remove_user_from_service_event(**kwargs):
+    _send_event('remove_user_from_service', **kwargs)
 
 
-def create_add_user_to_service_event(user_id, invited_by_id, service_id):
-    _send_event(
-        'add_user_to_service',
-        user_id=user_id,
-        invited_by_id=invited_by_id,
-        service_id=service_id
-    )
+def create_add_user_to_service_event(**kwargs):
+    _send_event('add_user_to_service', **kwargs)
 
 
-def create_archive_user_event(user_id, archived_by_id):
-    _send_event(
-        'archive_user',
-        user_id=user_id,
-        archived_by_id=archived_by_id)
+def create_archive_user_event(**kwargs):
+    _send_event('archive_user', **kwargs)
 
 
-def create_broadcast_account_type_change_event(
-    service_id,
-    changed_by_id,
-    service_mode,
-    broadcast_channel,
-    provider_restriction,
-):
-    _send_event(
-        'change_broadcast_account_type',
-        service_id=service_id,
-        changed_by_id=changed_by_id,
-        service_mode=service_mode,
-        broadcast_channel=broadcast_channel,
-        provider_restriction=provider_restriction
-    )
+def create_broadcast_account_type_change_event(**kwargs):
+    _send_event('change_broadcast_account_type', **kwargs)
 
 
-def create_suspend_service_event(
-    service_id,
-    suspended_by_id,
-):
-    _send_event(
-        'suspend_service',
-        service_id=service_id,
-        suspended_by_id=suspended_by_id,
-    )
+def create_suspend_service_event(**kwargs):
+    _send_event('suspend_service', **kwargs)
 
 
-def create_archive_service_event(
-    service_id,
-    archived_by_id,
-):
-    _send_event(
-        'archive_service',
-        service_id=service_id,
-        archived_by_id=archived_by_id,
-    )
+def create_archive_service_event(**kwargs):
+    _send_event('archive_service', **kwargs)
 
 
 def _send_event(event_type, **kwargs):
+    expected_keys = EVENT_SCHEMAS[event_type]
+    actual_keys = set(kwargs.keys())
+
+    if expected_keys != actual_keys:
+        raise ValueError(f'Expected {expected_keys}, but got {actual_keys}')
+
     event_data = _construct_event_data(request)
     event_data.update(kwargs)