The Promo module was a mockup. Three hardcoded rows, a toggle that changed
nothing, and no promo code anywhere in lib/domain or lib/data. A cashier
looking at it would reasonably conclude promotions were running.
Engine (domain/services/promo_engine.dart)
- Five campaign types: percent or flat off the bill, percent off a category
or a product, and buy-X-get-Y.
- Conditions: date range (inclusive of the closing day), days of the week,
minimum bill value, and a cap on what a percentage can take off — without
one an unusually large trolley gives away more than the campaign was costed
for.
- Stacking is conservative by default. All stackable campaigns apply together;
of the exclusive ones only the single best does, chosen by what it is worth
to the shopper with priority breaking ties. Two percentages compounding
produce a discount nobody signed off, and the shop finds out at the end of
the month.
- The total is capped at the subtotal, so no combination of campaign, tier and
manual discount can turn a sale into a payout.
- buy-X-get-Y counts whole groups only, and prices the free unit at what is
actually being charged — a line already carrying a manual discount must not
refund more than it took.
Kept out of Cart deliberately: Cart owns arithmetic that must never be wrong,
this owns policy a shop changes weekly.
Storage (schema v6, plus promos_json on orders at v7)
- Campaigns persist locally, because a shop mid-promotion with a dead line
still has to honour the price on the shelf edge.
- A bill records the campaign name and the amount given, not a link to the
row. A campaign edited or deleted later cannot change what a past sale
shows, and a reprinted receipt still names what the shopper was given.
- On read-back the promo amounts are subtracted from the manual discount,
because bill_discount already contains them. Restoring both at full value
would discount the bill twice — the same shape as the bug that used to
overstate synced totals.
At the till
- Every cart mutation re-evaluates, so a promo cannot survive the line that
earned it being removed.
- A resumed parked bill is re-evaluated rather than restored: a campaign that
has since ended must not be honoured because the bill was parked while it
was running.
- Campaigns are named individually on the billing panel and the printed
receipt, so a shopper who came in for an advertised offer can see it applied.
Editor
- Full CRUD, admin-only, with validation for the cases that would save happily
and then silently never fire — a targeted campaign with no target, a
percentage over 100, an end date before the start.
Tests: 199 -> 210. Covers each campaign type, the eligibility conditions, the
stacking rules, the impossible-to-go-negative guarantee, GST recomputation
against the reduced total, round-tripping, and the double-count guard.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Cash drawer
- openCashDrawer was a debugPrint. The drawer never opened.
- It cannot go through the PDF pipeline: a PDF is rendered by the platform
driver, which will not pass raw ESC/POS bytes to the device. So it goes over
a socket instead — nearly every network thermal printer listens on 9100 and
forwards whatever arrives straight to the print head, which makes the whole
protocol five bytes.
- Printer IP and port are configurable in Settings with a Test button that
saves and fires immediately, because a drawer that does not open is
indistinguishable from one that is not wired up.
- Every failure explains itself: unreachable, refused, or simply not
configured — which is the honest state for a USB printer, since there is no
raw path to one from Flutter.
- Now fires only on a cash tender. A card-only sale that pops the drawer is a
shrinkage risk, and it is the first thing a shop notices.
Back-office route
- Host, port, TLS and transport persist to the database; username, password
and API key go to the platform keystore (Keychain / Credential Manager /
Android Keystore). Writing credentials into SQLite would put them in the
same file as the bills, on a machine behind a shop counter.
- Loaded at startup. Previously the dialog wrote settings that were silently
ignored on the next launch, which reads exactly like they never saved — and
credentials retyped every morning end up on a sticky note instead.
- A saved route never overwrites the terminal's store or terminal id. Those
belong to the device, and re-pointing a till at a different broker must not
change who it is, or its bills and presence records stop lining up.
Tests: 168 -> 176. The drawer test stands up a real socket server and asserts
the exact bytes arrive. The config test asserts no credential appears anywhere
in the meta table while the non-secret settings do.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Wires the last two dead buttons in Settings and closes the loop on the
credential work: hashed PINs are only worth having if a shop can actually
change them.
Users & roles (Manage)
- Add, rename, re-role and remove staff. Admin-only at the door, because
anyone who can edit staff can make themselves an admin.
- PIN and confirmation are both required and must match. There is no email to
reset a PIN with, so a typo nobody can verify locks the account out until an
admin intervenes.
- Editing someone leaves their PIN alone unless a new one is typed. An admin
setting another person's PIN counts as a reset and re-arms must-change.
- Removal is a deactivation with a confirmation that explains why: bills
already rung keep the cashier's name, so shift reports stay correct.
- Anyone still on a shipped PIN is flagged in the list and in Settings.
Store details (Edit)
- Name, address, GSTIN and phone now editable and persisted. GSTIN is format
and state-code validated; it prints on every invoice as a legal requirement,
so a typo is a compliance problem across hundreds of bills.
- Admin-only: changing the GSTIN changes what every future invoice claims
about who collected the tax.
Forced PIN change
- Shown once after sign-in while must-change is set, and not dismissable. The
seeded PINs are in the source of the build, so a terminal still running one
is effectively unprotected.
Fixed while testing: the role dropdown laid its items out at natural width and
"Manager — Sales, inventory and reports" overflowed the dialog by 222px. Now
isExpanded with the description spelled out below, where it is readable.
Tests: 160 -> 168. Covers both role guards, the mismatched and too-short PIN
paths, the default-PIN flag, and GSTIN and seller-name validation.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Three StaffUser constants carried plaintext PINs (1234/2345/3456) in
auth_controller.dart. Every build shipped every till's credentials, readable
by anyone who unzipped the APK. Across 100 deployed devices that is one
credential, not a hundred.
- Schema v5 adds a staff table. Only a PBKDF2-HMAC-SHA256 hash and a per-user
random salt are stored; the PIN itself exists nowhere, including there.
12,000 iterations, tuned so one sign-in is imperceptible while working
through all 10,000 four-digit PINs against a stolen database takes ~15
minutes per account instead of milliseconds.
- Verification is constant-time. String == returns at the first differing
byte, and that timing leaks how much of a guess was right.
- StaffUser no longer has a pin field at all, so the credential cannot drift
back into memory, into widgets, or into a const declaration.
- Weak PINs are refused: under four digits, non-numeric, repeated digits, and
sequences. Two staff cannot share a PIN — the till identifies a cashier by
PIN alone, so a shared one would attribute bills to whichever row was
checked first.
- The last admin cannot be demoted or deactivated. A till with no admin cannot
be administered, including to appoint one, and recovering means editing the
database by hand.
- Staff are deactivated, never deleted, so bills already rung keep naming a
real person.
Seed accounts are now 4821/5093/6274 rather than 1234/2345/3456 — the weak-PIN
rule refuses the old ones, and a default the rule itself would reject is not a
defensible default. All three are flagged must-change-pin so they get a shop
trading on day one without becoming permanent.
Store details are now editable data, not compile-time constants. Name,
address, GSTIN and phone persist to the database and are read back rather than
falling through to the build's constants, which would silently undo a failed
save. GSTIN is format-validated including the state code — it prints on every
invoice as a legal requirement, so a typo is a compliance problem across
hundreds of bills before anyone notices.
Tests: 141 -> 160. Includes a test that reads every column of every staff row
and asserts no seed PIN appears anywhere in the database.
Migration test now asserts v5 and that an upgraded terminal comes up with the
staff table present but empty — seeding is the store's job on first open, so
an existing shop is never handed accounts it did not create.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The Customers module's primary action did nothing. The sheet it needed was
already built and in use at checkout, so this reuses it — a customer added
from the book now goes through the same validation, including the
duplicate-mobile guard.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Settings > Connectivity > Configure now points a terminal at a back office.
Until this existed a store was wired up by editing syncConfigProvider and
rebuilding, which made every terminal in a fleet its own build.
- Transport picker (offline demo / HTTP / MQTT) with only the relevant fields
shown, validated: an MQTT route with no host is refused rather than silently
saved, because a terminal pointed at nothing looks exactly like one that is
merely offline.
- Terminal name and store id are editable and persist to the database. The
device id and terminal code are shown but not editable, with a copy button —
they are what a support call needs, and re-coding a till must not orphan the
bills already written under the old code.
- TLS defaults on, with a note that bills carry customer names and numbers.
- About card now shows the real terminal, device id and store instead of the
literal TERM-01, and the dead "Check for updates" button is now the entry
point to this dialog.
Lints cleared, analyzer now reports zero issues:
- SoundService wrapped a plain bool in a getter and setter that did nothing.
- Two post-await guards used context.mounted inside a State, which the
analyzer cannot relate to the State's own lifetime. Both are now `mounted`.
Tests: 140 -> 141. The new widget test drives the dialog end to end and asserts
that saving an MQTT route with no host keeps the dialog open with the error
visible. Suite run three times clean.
Known gap, documented in docs/sync-contract.md: broker credentials live in
memory and must be re-entered after a restart. Persisting them means
encrypting at rest.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Answers "which of my 100 tills are alive and healthy", and fixes three things
that were fine on one device and broken on a hundred.
Terminal identity (lib/data/local/terminal_identity.dart)
- Every device mints a UUID on first run, stored in its own database, plus a
short code (T4A9) derived from it. Renaming keeps the device id, so history
keeps pointing at the same physical till.
- Replaces the literal 'TERM-01', which was hardcoded in five places. The whole
fleet reported as one terminal: shift reports merged, MQTT topics collided,
and a second connection with the same client id evicts the first from the
broker — so two tills would have knocked each other offline in a loop.
Invoice numbers now carry the terminal code
- INV-2608-T4A9-00042. The sequence counter lives in each till's own database
and starts at 1, so without this every terminal in the fleet minted
INV-2608-00001 for its first sale of the month. The order UUID kept the data
distinct; the number a customer quotes on a receipt was not.
SQLite pragmas
- WAL, so the product grid refreshing does not block the sale being written,
and the file is never left mid-rewrite by a power cut.
- busy_timeout 5s, so a contended lock waits instead of throwing "database is
locked" — which at checkout is a failed sale with a customer standing there.
- synchronous NORMAL, the right trade under WAL for a till.
Fleet presence (lib/data/sync/presence_reporter.dart)
- Retained status record on connect and once a minute: device id, code, name,
app version, pending bill count, last upload, catalogue revision, sync halt
state. Retained so a dashboard connecting at noon gets all 100 terminals
immediately rather than a blank board.
- The Last Will already said "reachable". A till can be connected and still be
holding 200 unsent bills or running last month's prices; only pending_bills
and catalogue_revision say so.
NATS
- The MQTT gateway maps / to . so the existing transport works unchanged.
SyncConfig.asNatsSubject() exposes the translation, and the contract doc
gives the JetStream subjects (pos.*.*.order, pos.*.*.status) plus the two
server-side requirements: a file-backed stream, and the ack published by the
consumer after commit rather than by the ingest handler.
Tests: 129 -> 140. New coverage for identity minting and stability, per-device
invoice uniqueness, topic and client-id separation, NATS subject mapping, and
the two pragmas. Suite run three times clean.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Turns the orders table into a queue that empties itself. Bills were only
uploaded when a cashier pressed Sync at end of day; a till that was never
pressed held a day's takings indefinitely.
Drain engine (lib/data/sync/sync_engine.dart)
- Triggers on sale committed, network regained, 5-minute poll, head-office
request, and the manual button.
- Single flight: a busy till firing a trigger per sale would otherwise have
several passes reading the same pending rows and send every bill twice.
A trigger arriving mid-drain is queued and replayed, so nothing is dropped.
- Exponential backoff with +/-20% jitter to a 5-minute ceiling. The jitter
matters: a store's terminals all fail at the same instant when the line
drops, and would retry in lockstep without it.
- Halts rather than loops on a failure retrying cannot fix (bad credential,
refused batch). Pressing Sync clears the halt.
Transports (lib/data/remote/)
- OrderTransport interface; MQTT, HTTP and simulated implementations. The
repository does not know which is in use.
- MQTT: QoS 1 uplink, application-level ACK correlated by batch_id on a return
topic, retained Last Will for terminal-offline detection, downlink for
catalogue pushes and remote sync requests.
- A broker PUBACK is never treated as acceptance. It means the broker holds
the bytes, not that the ledger took the sale. Only ids the back office names
are marked synced; silence leaves a bill pending.
- HTTP carries a stable idempotency key across retries of the same bills.
Retention
- Accepted bills are kept 7 days instead of deleted, so a batch the back
office later loses can be re-sent in full. Purged after that; archived
totals stay forever.
- forBusinessDate now reads pending rows only. A retained bill exists in both
the orders table and day_archive, and summing both would overstate the day.
Fixes found while building this
- SyncEngine._refreshPending wrote state.copyWith(pending: await ...). Dart
evaluates the receiver before the awaited argument, so a connectivity drop
during the wait was silently overwritten by the stale snapshot. Caught by
the first run of the new engine tests.
- PrinterSettingsController wrote state after four awaits with no mounted
check, throwing "used after dispose" when Settings was left mid-load. This
was pre-existing and reached the cashier as a red screen.
Also
- Header pill now reports real sync state: LIVE / n QUEUED / SYNCING /
SYNC HALTED, with an explanation of where the bills are.
- Settings shows the route, last upload, next retry and retention window.
- docs/sync-contract.md states what the back office must implement, including
the idempotency requirement that at-least-once delivery makes mandatory.
Tests: 90 -> 129 passing. New coverage for backoff shape and jitter band,
single flight, halting, ACK correlation and partial acceptance, at-least-once
duplicate handling, retention and purge, and no double-counting after a sync.
Suite run six times clean.
Not addressed: bills already synced by an older build went up overstated and
still need server-side reconciliation. Broker credentials have no Settings
editor yet.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Bills were persisted correctly but read back wrong. The read path rebuilt a
cart from its lines alone, dropping bill-level discounts and loyalty, so every
figure derived from a stored bill was overstated: the upload payload, the day
archive and the shift report. A discounted 529 bill read back as 620.
Money and data integrity
- order_dao: restore bill_discount and points_redeemed when rebuilding a cart;
keep the reconstruction tier-less so the membership discount is not applied
twice. Trust the recorded total and points via SaleTransaction.storedTotal.
- checkout_sale + order_dao.commitSale: write the bill, its stock movement and
the loyalty update in one transaction. Previously a failure part-way through
left a persisted bill the cashier believed had failed, inviting a duplicate.
- checkout_sale: re-check every line against live stock. A parked bill resumed
after its stock was sold passed validation and oversold.
- catalogue_dao: allocate the invoice sequence in one transaction; the previous
read-modify-write could hand two sales the same number and fail UNIQUE.
- local_store: replay unsynced sales after a catalogue import, so a mid-shift
re-import cannot restore stock that has already been sold.
- payment_controller: stamp the signed-in operator on the bill instead of the
hardcoded seed session, and pass the terminal id through.
- cart: reconcile per-slab GST against the bill total so the parts sum to the
whole on a tax invoice.
Sync and reporting
- sync_repository: drain unsynced bills in a loop rather than silently capping
at one page; stop on rejection so rejected rows cannot loop forever.
- sync_log_dao (new): persist the sync history to the sync_log table, which the
schema already defined but nothing used. It was in memory, so the only record
that bills had been uploaded died at restart.
- Scope shift reports by cashier. day_archive is re-keyed to
(business_date, cashier_name) so a till stays settleable after its bills are
uploaded and deleted. Schema v4 with a migration that carries v3 rows across.
Input and UI
- barcode_service: consume machine-paced keystrokes so a scan cannot also land
in the focused field, and raise the bar to 60ms/char while a text field has
focus so typing a mobile number is not read as a scan. Clock and focus check
injected so the behaviour is testable.
- primary_button: make the label flexible; label plus trailing total overflowed
the Charge button by up to 131px.
- app_router: redirect instead of null-casting when the receipt route is
entered without its transaction.
- customer_repository: reduce the search query to digits so a punctuated mobile
number matches.
Cleanup
- Remove TransactionRepository.save, CustomerRepository.recordSale and
OrderDao.insertOrder, all superseded by commitSale.
- dart fix across the tree; 251 analyzer issues down to 3 info-level.
Tests: 23 passing / 15 failing -> 90 passing. Fixed the two defects that broke
the existing suite (containsAll type argument, reset() needing a catalogue) and
deleted the leftover template test. Added coverage for the order round trip,
the day archive after a real sync, stock safety, checkout atomicity, the v3->v4
migration, scanner-versus-human input, and an app-level smoke test that renders
every module.
Note: bills already uploaded with a discount went up overstated. This stops it
happening again but does not correct historical server data.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
