Change History

The change history system records every field-level edit made to episodes, scenes, and scene blocks. It enables granular undo — reverting a single field change — as well as batch undo that rolls back an entire save action.

Data model

Field	Type	Description
id	number	Primary key
batchId	string	UUID shared by all changes from a single save action
entityType	string	episode | scene | scene_block
entityId	number	ID of the changed entity
changedField	string	Name of the field that changed
oldValue	string	JSON-serialized previous value
newValue	string	JSON-serialized new value
changedById	number	User who made the change
changedAt	Date	Timestamp

How batching works

When a user saves a form that updates multiple fields at once, the service generates a single batchId UUID and stamps it on every resulting change record. Reverting by batchId restores all those fields atomically.

Revert mechanism

POST /change-history/:changeId/revert reads the oldValue, parses it, and calls the appropriate entity update service method. The revert itself is recorded as a new change entry (so it can be reverted too).

Frontend

The change history panel is opened from the History button in the block/scene editor. It lists changes chronologically and provides Revert buttons per row and per batch.

Storage considerations

Change history grows indefinitely. If history tables become large, consider periodic archiving of old records (e.g. changes older than 90 days on completed episodes).