The core competitive moat (PRODUCT_STRATEGY.md §3.1): checkout can no
longer complete without a valid, still-available slot, on any Shopify
plan. User confirmed writing Functions in JS rather than Rust — no Rust
toolchain was available in this environment, and IMPLEMENTATION_PLAN.md §1
explicitly allows JS as a fallback ("Rust preferred, JS acceptable").
- app/services/holds.server.ts: Redis-backed soft slot-holds with TTL.
Hold creation is a Lua script (EVAL) — the "does this slot have room"
check and the reservation itself have to be one atomic Redis operation,
or two concurrent requests can both read "one spot left" and both
succeed. Outstanding holds per slot live in a sorted set scored by expiry
(so eviction is just ZREMRANGEBYSCORE, no separate expiry job needed to
read a correct count), and a repeat request from the same cart renews
its own hold instead of competing against the capacity gate again.
- app/routes/apps.scheduling.hold.tsx: public app-proxy endpoint the widget
calls the moment a shopper picks a slot — reserves capacity BEFORE the
cart attribute is written, since the attribute alone is just two
shoppers racing to write the same field.
- extensions/datetime-widget: now fetches the cart token, requests a hold
first, and only writes cart attributes on success; shows an error and
refreshes the slot list if it loses the race.
- app/services/booking.server.ts + webhooks.orders.create.tsx: converts an
order's dd_* cart attributes into a confirmed Booking (idempotent on
orderId — webhooks redeliver), releases the matching hold, and writes a
`delivery_datetime.booking` order metafield so the slot is visible on the
order record natively (IMPLEMENTATION_PLAN.md §5.2/§2). Deliberately does
NOT re-check capacity and reject at this point — by the time an order
exists, payment has happened; that's the Function's job, earlier.
- webhooks.orders.cancelled.tsx: marks the Booking cancelled, freeing its
capacity.
- extensions/validation-slot (Cart/Checkout Validation Function): blocks
checkout when the cart's dd_* attributes are missing or incomplete — a
shopper who bypasses the widget entirely (clears the attribute, calls the
cart API directly) still cannot check out, because this runs inside
Shopify's own checkout, not the browser. Scope note documented in
evaluate.js: this doesn't yet re-validate against a live capacity
snapshot at the moment checkout completes ("has since been taken" in
§3.1) — Functions can't call our DB, and a metafield-snapshot refresh
pipeline for that is unscoped work; the 10-minute hold TTL is the interim
mitigation for that specific race.
- extensions/delivery-customization: relabels every delivery option to the
shopper's actual chosen method + date ("Pickup — Aug 25" instead of a
generic carrier label), directly fixing the "estimated delivery date on a
pickup order" complaint §3.1 names. payment-customization is deliberately
NOT built yet — there's no configurable payment-method rule for it to
enforce until later phases add one; shipping a no-op Function serves
nothing.
- Prisma: added Booking (no SlotHold table — Redis is the sole source of
truth for holds, per §4's own "(Redis-backed)" annotation; mirroring it
into Postgres would just be a sync-consistency burden with no benefit).
- Both Function extensions are hand-scaffolded from Shopify's documented
JS Function structure (same interactive-login limitation as the Theme
App Extension) — README.md flags that `shopify app function schema`
should be run before deploying to confirm the input queries still match
the live schema.
New tests/integration/ suite (separate vitest config, needs live
Redis+Postgres — `docker compose up -d` locally, a services: block in CI)
holds the tests that can't be meaningfully mocked: the slot-hold
concurrency test CLAUDE.md calls out as non-negotiable (20 concurrent
requests for 1 unit of capacity → exactly 1 succeeds; 30 for 5 → exactly 5;
release-then-retry; TTL expiry; same-cart renewal) and the full
hold-to-booking lifecycle including idempotency on webhook redelivery.
Both Functions' pure decision logic is separately unit-tested (11 tests).
60 total tests now pass (52 unit + 8 integration).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Implements the "heart" of the app per IMPLEMENTATION_PLAN.md §6 Phase 2,
no UI yet by design:
- app/lib/time.ts: Luxon-based wall-clock helpers. slotDateTime() builds a
slot's instant from calendar-date + minutes-from-midnight by setting
hour/minute fields directly rather than adding an elapsed-time duration
to midnight — the latter is wrong by exactly one hour for any wall-clock
time on a spring-forward day, since a real elapsed-time addition crosses
the lost hour. Also detects and rejects wall-clock times that don't exist
in a spring-forward gap (Luxon silently rolls these forward instead of
invalidating them, so this required an explicit post-set field check).
- app/services/scheduling.server.ts: getAvailability(), a pure function
(no DB/Shopify calls — every input injected, including `now`) that
applies slot templates, date overrides, blackout dates, cutoff/lead-time,
and capacity to produce the bookable slots per date. Excludes unavailable
slots entirely rather than flagging them, per PRODUCT_STRATEGY.md §2.
- app/services/capacity.server.ts: remainingCapacity()/hasCapacity() — kept
as pure functions over an injected `consumed` count so this doesn't need
to change once Phase 4 adds real Booking/SlotHold-backed consumption.
41 unit tests total (up from 8), including DST regression tests that would
fail against a naive "midnight + elapsed minutes" implementation, an
ambiguous-time (fall-back) case, a nonexistent-time (spring-forward gap)
case, and a getAvailability run across the actual 2024 spring-forward date
verifying both the UTC offset change and that wall-clock hours stay correct
on both sides of it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Adds the scheduling core to Prisma (Shop, Location, Method enum,
SlotTemplate, SlotOverride, BlackoutDate — IMPLEMENTATION_PLAN.md §4) and
Polaris admin screens to manage them:
- /app/locations: list/create/edit/delete locations, one-click vertical
template seeding (bakery/florist/grocer)
- /app/slots: weekly slot template editor, scoped per location
- /app/blackouts: blackout dates, scoped to one location or all of them
services/templates.server.ts keeps the vertical presets as a pure,
unit-tested function (getVerticalTemplate) separate from the thin I/O
wrapper (seedVerticalTemplate) that does the actual Prisma writes, per
CLAUDE.md's "pure functions, inject data, no I/O in the math" rule.
Switched dev DB from SQLite to Postgres (docker-compose.yml, ports 5433/6380
to avoid clashing with other local projects already on 5432/6379): SQLite
doesn't support Prisma enums at all, and IMPLEMENTATION_PLAN.md's schema
relies on them (Method) plus Postgres-only array fields in later phases
(Zone.postalCodes, ProductRule.allowedLocationIds). Only one throwaway
migration existed, so switching now avoids compounding the rework later.
Also fixed a Remix/Polaris integration issue hit while building these forms:
this Polaris version's TextField/Checkbox are fully controlled (no
defaultValue/defaultChecked), and `data()` imported from `@remix-run/react`
(rather than `@remix-run/node`) breaks useActionData's type inference —
both are now handled correctly across the new routes.
Verified: lint, typecheck, unit tests (incl. template-seeding fixtures),
build, and a live end-to-end run of seedVerticalTemplate against the
Postgres container all pass.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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