Bring the legacy ParkSQL2017 pricing BREADTH onto our engine while keeping
integer-minor-unit money + immutable signed versions (rejecting legacy's
float money / mutable rows). TariffStructure becomes a discriminated union:
V1 = the original bare ladder (UNCHANGED, verbatim algorithm, golden-
regression-tested against the live version); V2 = {version:2, tz, shared
knobs, defaultCard, windowedCards[]} where each card is flat OR a block
ladder and may be scoped by wall-clock hour window / day-of-week / date
range / vehicle category.
computeFeeV2 prices by stepping one increment at a time, advancing the
ladder by ELAPSED minutes (continuous) while selecting the active card by
WALL-CLOCK time in the version's FROZEN tz. Decisions: tz is a per-site
setting (site_config.timezone, default Europe/Tirane) stamped server-side
into each version on publish — never the host clock (reproducibility);
default-card cap governs a mixed day; precedence = specificity
(date>dow>hour) -> priority -> name (total, order-independent), validation
rejects ambiguous ties; category = a card FIELD, frozen in the signed
vehicle_entry payload (site_config.default_vehicle_category default), read
at both pricing call-sites.
Composer: default card front-and-centre (flat/ladder toggle), tiers under
an "Advanced" disclosure; emits BARE V1 when no tiers (back-compat). DB:
migrations 0005 (timezone) + 0006 (default_vehicle_category). Stood up
vitest in @parking/shared (was zero tests on the ledger-feeding fee fn);
36 tests incl. golden V1 regression, happy-hour/overnight/dow/flat/category/
cap edges, precedence shuffle-invariance, Europe/Tirane DST determinism,
validation matrix — all green. No event-chain change.
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
Version selection is "latest tariff_version with effectiveFrom <= entry time",
but the publish handler accepted ANY effectiveFrom (defaulting to now). So an
admin could publish a version with a backdated effectiveFrom and silently
reprice sessions that had already entered — the retroactive rewrite the
versioning exists to prevent. Pricing itself was sound (quote resolves by entry
time; payment records tariffVersionId, freezing completed sessions); the leak
was the publish side only.
Reject effectiveFrom earlier than now (60s skew tolerance); future-dated
(scheduling a price change) stays allowed; bad ISO -> 400. Combined with
entry-time selection this is structural: once a car has entered, no later
publish can reprice it. Did not pin tariffVersionId onto vehicle_entry (not
needed). Verified 5/5 via inject against a copy of the live DB.
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
validateTariffStructure (shared): non-negative ints, ascending block bounds,
only the last block open-ended — a malformed card can't be published.
Routes: GET /api/tariff (active + history, any signed-in role), POST
/api/tariff/versions (publish an immutable, effective-dated version; admin
only). The single site tariff row is created lazily. Editing = publish a new
version; past sessions keep their pricing.
Web: TariffComposer in the admin shell — edit currency, grace windows,
increment, daily cap, lost-ticket fee, and add/remove rate blocks (major-unit
input -> minor on submit); shows active version + history.
Verified via inject: empty -> active null; invalid blocks -> 400 with problem;
valid -> 201; readonly publish -> 403; after publishing, the pay station quote
returns 404 (no session) instead of 409 (no tariff) -- it now prices against the
active card.
julian