Booking — Combine booking rule

The combine booking rule decides whether, when you edit a booking, related bookings (placed in the same action) are loaded together for editing. It is a rule about edit & attendance scope, NOT about price (price is the discount rule).

Configuration: CombinedBookingOption

Enum CombinedBookingOption (Tux/src/Tux.Core/Enums/RegularCasualBookingOption.cs), stored on ProgramCategory.CombinedBookingOptionId:

Option	Code	Load scope on edit
Term_Program_Set	0	Same course only (default behaviour).
ProgramCategory	1	Across courses within the same program category.

ActionLogId — the grouping key

Bookings placed in the same action share an ActionLogId. The combine rule uses it to find "sibling" bookings:

• CombinedBookingOptionId = 1: load every editable booking with the same ActionLogId in the same program category, even across courses — without asking for confirmation.
• Otherwise: keep the old behaviour — suggest only candidates with the same ActionLogId in the same course (ticket 9384), still asking via the related-attendee popup.

Example: TermCare has CombinedBookingOptionId = 1; a Before School Care and an After School Care booking share an ActionLogId → editing one loads both.

Exclusion rules

The system does not load into combined edit when:

• The ActionLogId differs.
• The program category differs (even with the same ActionLogId).
• It is outside the customer account scope / authorized admin scope.

Candidate validation

Every id submitted in a combined edit is validated before creating/updating an edit order:

• Same non-null ActionLogId and same program category.
• Inside user scope; active, editable, unlocked, no conflicting pending order.
• Any violation → the whole request is rejected; no partial edit order for the valid subset.

Effect when removed from the group

When reconfirming a combined booking causes one booking to be removed from the group:

• That booking → Canceled.
• Its active TermAttendance is deactivated in the same confirm operation.
• Retained bookings stay active (unless the diff changes them separately).

Discovering combined existing bookings

When entering a create/edit flow where the current account/attendee already has same-ActionLogId bookings under a combined category, the Booking UI preselects the account and loads the combined group without requiring account selection (admin attendee-first search resolves the account first).

Related invariants

• INV-BOOK-20 — combined edit expands the category ActionLog group.
• INV-BOOK-19 (v2) — non-combined keeps same-course behaviour; validates category ActionLog scope.

Source of truth: openspec/specs/booking/spec.md (the "Combined booking edit…" requirements).

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