Three changes to the POS sale pipeline, all in one commit because
pos-service.ts / types.ts / pos-app.js are each touched by all three and
splitting them would only produce intermediate broken states.
VAT is now charged on top, not backed out
Catalogue prices are ex-VAT: `selling_price` is derived as
`cost_price x markup` from the supplier's ex-VAT cost, with no VAT
uplift anywhere (verified — median selling/cost across the catalogue is
exactly 1.8). The till nevertheless treated them as VAT-inclusive and
recovered the net with `total / 1.15`, so every sale was recorded with
an understated net and an understated VAT line.
An R100 ex-VAT line now rings up as R115. The rate comes from the till's
letterhead, read server-side rather than accepted off the wire, and is
stored per sale so a later letterhead rate change cannot rewrite what
was charged. All 3,623 catalogue prices are untouched.
Ad-hoc "custom" lines
A cashier can now ring up something that was never a catalogue item —
"bolt cutting" at R20 agreed at the counter — via a new
"+ Add a custom item" composer. The line prints on the slip and lands in
pos_sale_items, but carries no stock_item relation and takes no stock
movement: no ledger row, no current_qty decrement, no catalogue entry.
pos_sale_items.stock_item is no longer required at the schema level and
an explicit `is_custom` flag marks the line, rather than inferring it
from a blank relation — so "how much did we make on bolt cutting this
month" is a plain query, and a future stock-less line type cannot be
confused with a corrupt one.
Custom lines are refused on account sales: those raise a delivery note
the customer signs for and feed their statement, so an ad-hoc charge
must not slip onto one. Enforced server-side, not just in the UI.
Discounts are now 20% or 40%, nothing else
The R-off / %-off pills and the free-typed number box are gone. The
server treats DISCOUNT_PERCENT_OPTIONS as an allowlist and refuses
anything outside it rather than coercing it, so a stale till cannot
invent a discount. The discount lands on the ex-VAT subtotal, making
"20% off" a true 20% off both the net and the VAT on it.
Two defects found while doing this
pos_sales was missing six fields that checkoutSale has been writing all
along (gross_subtotal, gross_vat, gross_total, discount_amount,
discount_kind, discount_input). PocketBase accepts unknown fields
without error and silently drops them, so all 192 historical sales lack
them and a discounted sale reprinted as though no discount had been
applied. Added, plus vat_percent.
History also passed gross_total (VAT-inclusive) where the receipt
derives the gross VAT from an ex-VAT base — a reprint double-counted
VAT. Corrected.
Verification: 3860 tests pass (14 new); typecheck, lint and production
build clean; live PocketBase probe confirms a pos_sale_items row with
stock_item="" and is_custom=true round-trips, with the probe removed
afterwards.
A customer who brings goods back needs the sale reversed: the items go
back into stock and the money comes back off the till. There was no way
to mark a POS sale as refunded, so nothing stopped the same sale being
refunded twice — which credits the customer twice and puts the same
stock back on the shelf twice.
Refunds are WHOLE-SALE only by operator decision; no partial refunds.
That is what lets `pos_sales.refunded` be a boolean instead of a
per-line refund table. Three columns: `refunded`, `refunded_at`,
`refund_amount`, stamped from the sale's post-discount total, which is
what the customer actually paid.
DOUBLE-REFUND GUARD, twice over, because this is the one failure that
costs real money:
- `refunded` is read before anything else, and a flagged sale returns
409 with no stock writes at all
- the flag is stamped BEFORE any stock write, so a second concurrent
tap sees it and bails. Writing stock first and flagging last would
let both taps through.
A stock write that fails part-way does NOT roll the flag back. The
customer has their money either way, so re-running would double-credit
them; the failed lines come back in `stockErrors` for a manual count
correction, which is strictly better than a second refund.
Stock needs no schema: `return` was already in STOCK_REASON_VALUES,
just never used. Rows are written with POSITIVE change_qty and
reference_type "pos_sale_refund", leaving the original
customer_fulfillment rows untouched so the sale's own audit trail still
shows what was originally rung up.
cashup.html had expected drawer = sum of cash sales, so a cash refund
would have shown as a false variance on every cash-up after it. It now
subtracts cash refunds, and refunded sales contribute nothing to
takings for any tender.
The tender is read off the sale, never off the request — an earlier
version accepted it in the body, which would have let a caller assert
that a cash sale was really an EFT and talk the drawer out of balance.
At the till: tap still reprints, hold a sale row for 600ms to refund —
moving money sits behind a gesture you cannot do by accident. Refunded
sales stay in the list, dimmed and badged, because deleting them would
destroy the audit trail. The sheet names the items and says plainly what
happens next ("Hand back R10.57 in cash. The drawer count for this day
will drop by that amount.").
The credit slip reuses the sale renderer and the whole printer path with
`refund: true`, so there is no second printer to configure — but note
there were THREE render paths to fix (on-screen, Bluetooth text, ePOS
XML), and missing the third would have printed "TOTAL" on a credit note.
Migration applied to live PB and verified idempotent; field shapes
round-tripped on a real sale and restored. 10 new tests, 148 POS tests
pass, tsc clean, build passes. sw.js v34 -> v35 (history, cashup,
receipt and epos-print are all cache-first in the shell).
An account sale at the till used to produce a delivery-note-shaped slip that
was rendered entirely on the device and printed on the 80mm thermal printer.
Nothing reached the server, so the paperwork the client signed had no record
behind it. Cash / card / EFT are untouched and still get the thermal slip.
An account sale now creates a real `delivery_notes` record. The DN is raised
server-side INSIDE `checkoutSale` rather than by a follow-up call from the
till, because the offline queue (`flushQueue`) re-posts `/checkout` and
nothing else — a client-side second call would be silently dropped for every
sale taken while the network was down, which is exactly when a till is
flakiest.
`pos_sales.delivery_note` is the idempotency anchor that makes it
exactly-once: on a replay it hands back the existing DN instead of making a
second one, and a sale whose first attempt left the field blank retries. It
self-heals.
Deliberately non-fatal: if the DN can't be created the sale still succeeds.
The money and the stock movement are real by then; failing the checkout would
leave the drawer disagreeing with the stock ledger. The till is told instead.
Also in here:
- DN number collision retry. The generator reads the highest existing number
and adds one, which is not atomic, while PB holds a unique index on it. The
POS adds a second concurrent writer, so two creates could collide and 500
on a benign condition.
- GET /api/v1/pos/sales now expands customer, customer.company and
delivery_note so history.html can rebuild the DN card on a reprint. The
nested customer.company matters — customer.company is itself a relation,
so without it the card printed a raw PB id where the name belongs.
- "Print slip" is hidden for account sales; that tender produces a delivery
note, not a slip.
New GET /api/v1/pos/delivery-note/[number]/pdf streams the A4 original behind
assertPosAuth, so the till's bearer key stays its only credential. It does not
point at the CRM's unauthenticated invoicing route.
Verified end to end against a live note: DN26100401, correct company, both
lines with pricing, PDF attached, stock decremented once, and a replay of the
same client_ref returned the same DN without a duplicate.
Logo — three separate faults, all of which had to be fixed for the
letterhead logo to print at all:
1. receipt.html hardcoded '/wfdash-logo.png' for the sale slip, so it
printed the app's bundled mark (the solid black W block) and never
looked at the letterhead at all.
2. The paths that DID use the letterhead (printTest, cashup) passed
PocketBase's fully-qualified cross-origin URL into imageToRaster(),
which draws to a <canvas> — getImageData() taints and throws on a
cross-origin image, so the .catch(() => null) silently dropped the
logo. pos-letterhead-service now returns a same-origin
/api/v1/files/... URL (per AGENTS.md's file-URL rule).
3. letterhead_settings wasn't whitelisted in that file proxy, so the
same-origin URL would have 403'd.
Verified against the live WESTSCOTT letterhead: its SVG rasterizes to
384x137 at ~15% ink coverage (line art), no tainted canvas.
Also fixes the company name never printing: every builder read
`letterhead.name`, but the POS letterhead record exposes
`display_name` — so the name line silently rendered empty on every
slip, on screen and on paper.
Delivery note now matches the sale slip, per request: gains the logo
and business_info blocks and the same 2x-size title, instead of being
a stripped-down variant. This also reconciles the transport
divergence flagged earlier (Bluetooth baked business info into its
header; the network builder omitted it entirely) — it is now one
reorderable business_info block on both.
resolveBlocks() now slots a newly-shipped block in at its intended
position rather than appending it to the end. Without this, any
letterhead with an already-saved layout would have printed the new
logo/business_info blocks BELOW the signature line.
Root cause of the oversized/wrapping text on the printed slip: ePOS-
Print XML's <text> attributes (width, height, em) are stateful on the
printer — they persist across subsequent <text> tags until explicitly
changed back, not per-tag like CSS. The sale slip's header_title block
sets width="2" height="2" for the big title and nothing after it ever
reset back to width="1" height="1", so the entire rest of the receipt
(business info, items, totals, payment, footer) inherited double-size
text — exactly the wrapping/misalignment seen in the photo. Same
issue existed in the delivery note (header's height="2" leaking into
every line after it) and cash-up (GRAND TOTAL's em="true" leaking
into CASH RECONCILIATION's non-bold lines).
Now every <text> tag in all three XML builders explicitly declares
width/height/em rather than relying on inheritance from whatever
tag ran before it. This isn't just a display fix — since blocks are
now user-reorderable/toggleable, no block can safely assume what
state a neighboring block left behind; every block must be correct
in isolation regardless of order.
Same class of bug existed on the Bluetooth ESC/POS side: ESC/POS's
alignment command is equally persistent, and the sale slip's
header_title centered the title but relied on the next block
(business_info) to reset it back to left — broken the moment
business_info is disabled or reordered. Fixed the same way: each
block resets what it changed before returning.
Also fixes a live bug found while refactoring: buildEscPos returned a
Uint8Array, but its caller in printThermalBluetooth() ran the result
through TextEncoder.encode() (which expects a string) before writing
to the Bluetooth characteristic — encoding a Uint8Array's default
toString() ("27,64,27,...") instead of the actual bytes. Regular
(non-account) sale slips printed over Bluetooth have been sending
garbled data. Both builders now return plain strings, matching
buildEscPosDelivery's already-correct pattern.
Also preserves a pre-existing divergence rather than silently
resolving it: Bluetooth's delivery note prints letterhead business
info (name/address/phone/VAT), the network XML version never has.
Kept as-is per transport (folded into Bluetooth's header_title block)
rather than unilaterally adding or removing content — worth an
explicit decision later on which behavior is correct.
Added support for discounts in the POS checkout process, allowing operators to apply either a fixed amount or a percentage off the gross total. Updated the state management to include discount details and modified the receipt and cart rendering to display pre- and post-discount values. Enhanced the checkout API to handle discount inputs and ensure proper calculations. Updated relevant tests to cover new discount logic.
The Include-prices toggle drives both the on-screen slip and the
Bluetooth thermal print, so what prints matches what the operator saw.
Co-Authored-By: Claude <noreply@anthropic.com>
pb-config.js deliberately not copied — it hardcoded a PocketBase
superuser email/password in client-shipped JS.
Co-Authored-By: Claude <noreply@anthropic.com>
