rose-ash/plans/events-on-sx.md

events-on-sx: Calendar, ticketing & notification delivery on Datalog

DRAFT outline. The events vertical + the shared notification-delivery edge. Depends on persist-on-sx (bookings ledger) and flow-on-sx (reminders, retrying delivery). Pairs with commerce-on-sx for paid tickets.

rose-ash's events domain is calendar + ticketing: recurring events, availability, capacity, bookings. Scheduling is constraint reasoning — "is this slot free given recurrence, capacity, and the attendee's other bookings?" — which is rule evaluation over facts. Datalog expresses availability, recurrence expansion, and capacity as rules; a booking is a transaction; reminders and digests are durable flows. Notification delivery (email/push) — needed here and by feed/notify — is folded in as an injected transport, extractable later.

End-state: a Datalog-on-SX events layer with recurrence expansion, availability + capacity rules, transactional booking, and a flow-driven notification dispatcher (reminders, digests, retries) over an injected transport.

Status (rolling)

bash lib/events/conformance.sh → 24/24 (Phase 1: calendar recurrence)

Ground rules

• Scope: only lib/events/** and plans/events-on-sx.md. May import from lib/datalog/, and (once they exist) lib/persist/ + lib/flow/. Do not edit substrates.
• Architecture: events/availability/capacity are Datalog facts + rules; recurrence expands to occurrence facts within a window; a booking checks rules then appends a persist event (idempotent, capacity-safe). Notifications are flows that suspend on transport IO and retry on failure.
• Determinism: recurrence expansion + availability must be reproducible for a fixed window + ruleset; capacity checks must be race-safe (no overbooking).
• Commits: one feature per commit. Progress log + tick boxes.

Architecture sketch

Event + booking                         Result
  event(id,start,rrule,capacity)          {:booked | :full | :conflict} + reminders
        │                                       ▲
        ▼                                       │
lib/events/calendar.sx                  lib/events/availability.sx
  — event facts, recurrence (RRULE)       — free/busy + capacity rules (Datalog)
  — expand occurrences in window                │
        │                                       ▲
        ▼                                       │
lib/events/booking.sx                   lib/events/notify.sx   (flow)
  — transactional, capacity-safe          — reminders / digests, retry on fail
  — bookings → persist ledger               — injected transport (email/push)
        │                                       │
        ▼                                       ▼
lib/events/api.sx ── (events/schedule) (events/book) (events/agenda) ──────┘

Phase 1 — Calendar + recurrence

• calendar.sx — event facts, RRULE expansion in a window (DAILY/WEEKLY)
• calendar.sx — MONTHLY (bymonthday + nth-weekday byday)
• availability.sx — free/busy rules
• api.sx + tests + scoreboard + conformance.sh

Phase 2 — Ticketing + booking

• capacity rules; transactional booking → persist (no overbooking)
• paid tickets compose with commerce order flow
• tests: capacity edge, double-book guard, conflict detection

Phase 3 — Notification delivery (flow)

• notify.sx — reminder/digest flows over injected transport
• retry/backoff on transport failure (flow suspend/resume)
• tests: delivery success, retry path, idempotent re-send
• NOTE: shared with feed/notify — candidate for later extraction to a delivery-on-sx once a second consumer is real

Phase 4 — Federation

• cross-instance events (peer calendar) — trust-gated stub
• tests: federated agenda merge

Progress log

• 2026-06-06 — Phase 1 scaffold + calendar recurrence. calendar.sx: integer epoch-minute datetimes, Hinnant civil<->day-number conversion, DAILY/WEEKLY RRULE expansion in a bounded (start,end) window with INTERVAL, COUNT (window- independent), UNTIL, BYDAY (weekly). ev-expand-all merges + sorts. Wired conformance harness (conf + thin wrapper reusing lib/guest/conformance.sh), scoreboard. 24/24 green. MONTHLY deferred to next commit.

Blockers

• None. Substrates present: lib/datalog (276/276), lib/persist, lib/flow all exist — Phase 2/3 unblocked when reached.