kooltab-backoffice/apps/api/src/devices/devices.service.spec.ts

import { v4 as uuidv4 } from 'uuid';
import { DevicesService } from './devices.service';
import { SyncDto } from './dto/sync.dto';
import { createFakePrisma, FakePrisma } from '../testing/fake-prisma';
import { StockService } from '../stock/stock.service';

type Device = { id: string; venueId: string; revokedAt: null; lastSeenAt: Date };
type SyncResult = Awaited<ReturnType<DevicesService['sync']>>;

// In the past: a time ahead of the server clock would be capped
const at = (minutes: number) => new Date(Date.UTC(2026, 8, 24, 20, minutes)).toISOString();

function setup({ seeded = true } = {}) {
  const prisma = createFakePrisma();
  prisma.venue.rows.push({ id: 'v1', tabsSeededAt: seeded ? new Date('2026-10-01') : null });
  const tabletA: Device = { id: 'd1', venueId: 'v1', revokedAt: null, lastSeenAt: new Date() };
  const tabletB: Device = { id: 'd2', venueId: 'v1', revokedAt: null, lastSeenAt: new Date() };
  prisma.device.rows.push({ ...tabletA }, { ...tabletB });
  const realtime = { notify: jest.fn() };
  const service = new DevicesService(prisma as any, { log: jest.fn() } as any, realtime as any);

  const sync = (device: Device, body: Partial<SyncDto> = {}) =>
    service.sync(device, { deviceId: device.id, openTabs: [], ...body } as SyncDto);

  return { prisma, service, realtime, sync, tabletA, tabletB };
}

/** Builds the events a terminal sends, with fresh ids. */
const events = {
  opened: (tabId: string, customerName: string, minutes = 0) => (
    { id: uuidv4(), type: 'tab_opened', tabId, customerName, occurredAt: at(minutes), openedAt: at(minutes) }),
  renamed: (tabId: string, customerName: string, minutes = 0) => (
    { id: uuidv4(), type: 'tab_renamed', tabId, customerName, occurredAt: at(minutes) }),
  deleted: (tabId: string, customerName: string, minutes = 0) => (
    { id: uuidv4(), type: 'tab_deleted', tabId, customerName, occurredAt: at(minutes) }),
  line: (type: 'line_added' | 'line_removed', tabId: string, quantity: number, {
    minutes = 0, lineId = undefined as string | undefined, productId = 'cola', productName = 'Cola', price = 250,
  } = {}) => ({
    id: uuidv4(), type, tabId, customerName: 'Alice', occurredAt: at(minutes),
    lineId, productId, productName, unitPriceInCents: price, quantity,
  }),
  settled: (tabId: string, quantity: number, minutes = 0) => ({
    id: uuidv4(), type: 'settled', tabId, customerName: 'Alice', occurredAt: at(minutes),
    amountInCents: quantity * 250, paymentMethod: 'payconiq',
    items: [{ productId: 'cola', productName: 'Cola', quantity, unitPriceInCents: 250 }],
  }),
  product: (type: string, productId: string, product: Record<string, unknown> | undefined, minutes = 0) => (
    { id: uuidv4(), type, productId, ...(product ? { product } : {}), occurredAt: at(minutes) }),
  stockSet: (productId: string, quantity: number | null, minutes = 0) => (
    { id: uuidv4(), type: 'stock_set', productId, quantity, occurredAt: at(minutes) }),
};

const catalog = (stock: number | null = 0) => [
  { id: 'cola', name: 'Cola', category: 'Frisdrank', priceInCents: 250, stock },
];

function tab(result: SyncResult, tabId: string) {
  return result.tabs.find((t) => t.id === tabId);
}

function colaStock(result: SyncResult) {
  return result.stock.find((s) => s.productId === 'cola')?.stock;
}

describe('DevicesService.sync: the server holds the tabs', () => {
  it('shows a newly paired tablet the open tabs of the venue', async () => {
    const { sync, tabletA, tabletB } = setup();
    await sync(tabletA, { events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 2)] });

    const result = await sync(tabletB);

    expect(result.tabs).toHaveLength(1);
    expect(result.tabs[0]).toMatchObject({ id: 't1', customerName: 'Alice', version: 2 });
    expect(result.tabs[0].lines).toMatchObject([{ productId: 'cola', productName: 'Cola', quantity: 2 }]);
  });

  it('gives units the ids the tablets give them when replaying', async () => {
    const { sync, tabletA } = setup();
    const added = events.line('line_added', 't1', 2, { lineId: 'line-1' });

    const result = await sync(tabletA, { events: [events.opened('t1', 'Alice'), added] });

    expect(tab(result, 't1')!.lines[0]).toMatchObject({
      id: 'line-1',
      units: [
        { id: `${added.id}:0`, addedAt: at(0), removedAt: null },
        { id: `${added.id}:1`, addedAt: at(0), removedAt: null },
      ],
    });
  });

  it('adds what two tablets put on one tab', async () => {
    const { sync, tabletA, tabletB } = setup();
    await sync(tabletA, { events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 2, { lineId: 'line-1' })] });

    // Tablet B replayed its drink onto the server's line, so it uses that line id
    await sync(tabletB, { events: [events.line('line_added', 't1', 1, { lineId: 'line-1', minutes: 1 })] });
    const result = await sync(tabletA);

    expect(tab(result, 't1')!.lines).toMatchObject([{ id: 'line-1', quantity: 3 }]);
  });

  it('applies an event once, also when it arrives again in a later sync', async () => {
    const { sync, tabletA, prisma } = setup();
    const added = events.line('line_added', 't1', 1);
    await sync(tabletA, { events: [events.opened('t1', 'Alice'), added] });

    const result = await sync(tabletA, { events: [added, added] });

    expect(result.acknowledgedEventIds).toEqual([added.id, added.id]);
    expect(tab(result, 't1')!.lines[0].quantity).toBe(1);
    expect(prisma.tabEvent.rows).toHaveLength(2);
  });

  it('catches up with everything a tablet did offline, in order', async () => {
    const { sync, tabletA, tabletB } = setup();
    await sync(tabletB, { events: [events.opened('bob', 'Bob')] });

    await sync(tabletA, {
      events: [
        events.opened('t1', 'Alice', 1),
        events.line('line_added', 't1', 3, { minutes: 2 }),
        events.line('line_removed', 't1', 1, { minutes: 3 }),
        events.renamed('t1', 'Alice V.', 4),
        events.deleted('bob', 'Bob', 5),
      ],
    });
    const result = await sync(tabletB);

    expect(result.tabs.map((t) => t.customerName)).toEqual(['Alice V.']);
    const [line] = tab(result, 't1')!.lines;
    expect(line.quantity).toBe(2);
    // The latest drink was taken back
    expect(line.units.map((u) => u.removedAt)).toEqual([null, null, at(3)]);
  });

  it('settles only what the tablet saw, leaving a drink added elsewhere on the tab', async () => {
    const { sync, tabletA, tabletB } = setup();
    await sync(tabletA, { events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 2)] });
    await sync(tabletB, { events: [events.line('line_added', 't1', 1, { minutes: 5 })] });

    // Tablet A was offline and settled the 2 Cola it knew about
    const result = await sync(tabletA, { events: [events.settled('t1', 2, 3)] });

    expect(tab(result, 't1')!.lines).toMatchObject([{ quantity: 1, units: [{ addedAt: at(5) }] }]);
    expect(result.settlements).toHaveLength(1);
    expect(result.settlements[0]).toMatchObject({ tabId: 't1', paymentMethod: 'payconiq', amountInCents: 500 });
    expect(result.settlements[0].lines).toMatchObject([{ productId: 'cola', quantity: 2 }]);
    expect(result.settlements[0].lines[0].units.map((u) => u.addedAt)).toEqual([at(0), at(0)]);
  });

  it('brings a tab deleted elsewhere back with the drink that was put on it', async () => {
    const { sync, tabletA, tabletB } = setup();
    await sync(tabletA, { events: [events.opened('bob', 'Bob')] });
    await sync(tabletB, { events: [events.deleted('bob', 'Bob', 1)] });

    const result = await sync(tabletA, {
      events: [{ ...events.line('line_added', 'bob', 1, { minutes: 2, productId: 'beer', productName: 'Beer', price: 400 }), customerName: 'Bob' }],
    });

    expect(tab(result, 'bob')).toMatchObject({ customerName: 'Bob', lines: [{ productName: 'Beer', quantity: 1 }] });
  });

  it('matches events from older app versions by product name and price', async () => {
    const { sync, tabletA } = setup();
    const { lineId, productId, ...old } = events.line('line_added', 't1', 2);
    await sync(tabletA, { events: [events.opened('t1', 'Alice'), old] });

    const { lineId: _, productId: __, ...removed } = events.line('line_removed', 't1', 1, { minutes: 1 });
    const result = await sync(tabletA, { events: [removed] });

    expect(tab(result, 't1')!.lines).toMatchObject([{ productId: null, quantity: 1 }]);
  });

  it('does not apply a rejected event, and still syncs the rest', async () => {
    const { sync, tabletA } = setup();
    const invalid = { ...events.line('line_added', 't1', 1), quantity: 0 };

    const result = await sync(tabletA, { events: [events.opened('t1', 'Alice'), invalid] });

    expect(result.rejectedEvents).toEqual([{ id: invalid.id, reason: expect.any(String) }]);
    expect(tab(result, 't1')!.lines).toEqual([]);
  });

  it('opens planned customers as tabs once, instead of on every tablet', async () => {
    const { sync, tabletA, tabletB, prisma } = setup();
    prisma.plannedTab.rows.push(
      { id: 'p1', venueId: 'v1', customerName: 'Els', customerNameKey: 'els', deliveredAt: null, position: 0 },
      { id: 'p2', venueId: 'v1', customerName: 'alice', customerNameKey: 'alice', deliveredAt: null, position: 1 },
    );
    await sync(tabletA, { events: [events.opened('t1', 'Alice')] });

    const result = await sync(tabletB);

    expect(result.plannedTabNames).toEqual([]);
    expect(result.tabs.map((t) => t.customerName).sort()).toEqual(['Alice', 'Els']);
    expect(prisma.plannedTab.rows.every((p) => p.deliveredAt !== null)).toBe(true);
  });
});

describe('DevicesService.sync: taking over a tablet once', () => {
  it("takes over the tablet's tabs and stock without applying that request's events again", async () => {
    const { sync, tabletA, prisma } = setup({ seeded: false });

    const result = await sync(tabletA, {
      openTabs: [{
        id: 't1', customerName: 'Alice', version: 4, totalInCents: 750, itemCount: 3,
        items: [{ productName: 'Cola', quantity: 3, unitPriceInCents: 250 }],
      }],
      // Already in the tabs and stock above
      events: [events.line('line_added', 't1', 1)],
      products: catalog(45),
    });

    expect(tab(result, 't1')).toMatchObject({ customerName: 'Alice', version: 4, lines: [{ productName: 'Cola', quantity: 3 }] });
    expect(colaStock(result)).toBe(45);
    expect(prisma.venue.rows[0].tabsSeededAt).not.toBeNull();

    const next = await sync(tabletA, {
      openTabs: [],
      events: [events.line('line_added', 't1', 1, { productId: 'cola', minutes: 1 })],
      products: catalog(44),
    });
    expect(tab(next, 't1')!.lines[0].quantity).toBe(4);
    expect(colaStock(next)).toBe(44);
  });
});

describe('DevicesService.sync: settlements feed', () => {
  it("sends every tablet the venue's settlements once, after its cursor", async () => {
    const { sync, tabletA, tabletB } = setup();
    const settled = events.settled('t1', 1, 2);
    await sync(tabletA, { events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 1), settled] });

    const first = await sync(tabletB);
    expect(first.settlements.map((s) => s.id)).toEqual([settled.id]);

    const second = await sync(tabletB, { settlementsCursor: first.settlementsCursor });
    expect(second.settlements).toEqual([]);
    expect(second.settlementsCursor).toBe(first.settlementsCursor);
  });

  it('starts an empty feed after the latest settlement', async () => {
    const { sync, tabletA } = setup();

    const result = await sync(tabletA);

    expect(result.settlements).toEqual([]);
    expect(result.settlementsCursor).toBe('0');
  });
});

/** A product added on the dashboard, untracked. */
function addProduct(prisma: FakePrisma, productId = 'cola', fields: Record<string, unknown> = {}) {
  prisma.product.rows.push({
    venueId: 'v1', productId, name: 'Cola', category: 'Frisdrank', priceInCents: 250, stock: null, countedAt: null,
    lowStockThreshold: null, archivedAt: null, reportedAt: new Date(), ...fields,
  });
}

describe('DevicesService.sync: the dashboard manages the catalog', () => {
  it('sends every product, archived ones marked, and ignores what a tablet reports', async () => {
    const { sync, tabletA, prisma } = setup();
    addProduct(prisma, 'cola', { lowStockThreshold: 6 });
    addProduct(prisma, 'old', { name: 'Old', category: null, archivedAt: new Date() });

    const result = await sync(tabletA, {
      products: [
        { id: 'cola', name: 'Renamed on the tablet', category: null, priceInCents: 999, stock: 3 },
        { id: 'local', name: 'Seeded on the tablet', category: null, priceInCents: 100, stock: 24 },
      ],
    });

    // By category, products without one last (as Postgres sorts)
    expect(result.catalog).toEqual([
      { id: 'cola', name: 'Cola', category: 'Frisdrank', priceInCents: 250, lowStockThreshold: 6, archived: false },
      { id: 'old', name: 'Old', category: null, priceInCents: 250, lowStockThreshold: null, archived: true },
    ]);
    expect(prisma.product.rows).toHaveLength(2);
  });

  it("takes over the tablet's catalog when the venue is taken over", async () => {
    const { sync, tabletA } = setup({ seeded: false });

    const result = await sync(tabletA, { products: catalog(12) });

    expect(result.catalog).toMatchObject([{ id: 'cola', name: 'Cola', archived: false }]);
    expect(colaStock(result)).toBe(12);
  });
});

describe('DevicesService.sync: the server holds the stock', () => {
  async function trackedCola(sync: ReturnType<typeof setup>['sync'], tablet: Device, stock = 48) {
    return sync(tablet, { events: [events.stockSet('cola', stock, -10)] });
  }

  /** Every test here starts with Cola on the dashboard. */
  function setupWithCola() {
    const venue = setup();
    addProduct(venue.prisma);
    return venue;
  }

  it('ignores a count for a product the venue does not have', async () => {
    const { sync, tabletA } = setupWithCola();

    const result = await sync(tabletA, { events: [events.stockSet('local', 24)] });

    expect(result.stock).toEqual([{ productId: 'cola', stock: null, countedAt: null }]);
  });

  it('counts the sales of every tablet once', async () => {
    const { sync, tabletA, tabletB } = setupWithCola();
    await trackedCola(sync, tabletA);
    const sale = events.line('line_added', 't1', 2, { minutes: 1 });

    await sync(tabletA, { events: [events.opened('t1', 'Alice'), sale] });
    await sync(tabletA, { events: [sale] });
    const result = await sync(tabletB, { events: [events.line('line_added', 't1', 2, { minutes: 2 })] });

    expect(colaStock(result)).toBe(44);
  });

  it('gives stock back for drinks taken off, but not for a settlement', async () => {
    const { sync, tabletA } = setupWithCola();
    await trackedCola(sync, tabletA);

    const result = await sync(tabletA, {
      events: [
        events.opened('t1', 'Alice'),
        events.line('line_added', 't1', 3, { minutes: 1 }),
        events.line('line_removed', 't1', 1, { minutes: 2 }),
        events.settled('t1', 2, 3),
      ],
    });

    expect(colaStock(result)).toBe(46);
  });

  it('keeps a count when sales from before it arrive later', async () => {
    const { sync, tabletA, tabletB } = setupWithCola();
    await trackedCola(sync, tabletA);
    await sync(tabletB, { events: [events.stockSet('cola', 30, 60)] });

    const result = await sync(tabletA, {
      events: [
        events.opened('t1', 'Alice'),
        // Rung up offline before the count: already in it
        events.line('line_added', 't1', 2, { minutes: 50 }),
        // An older count from an offline tablet doesn't overwrite the newer one
        events.stockSet('cola', 70, 55),
        events.line('line_added', 't1', 3, { minutes: 70 }),
      ],
    });

    expect(colaStock(result)).toBe(27);
    expect(result.stock[0].countedAt).toBe(at(60));
  });

  it('applies a pending dashboard adjustment once and no longer sends adjustments', async () => {
    const { sync, tabletA, tabletB, prisma } = setupWithCola();
    await trackedCola(sync, tabletA);
    prisma.stockAdjustment.rows.push({
      id: 'adj-1', venueId: 'v1', productId: 'cola', productName: 'Cola', type: 'add', quantity: 24,
      status: 'pending', createdAt: new Date(),
    });

    const first = await sync(tabletA);
    const second = await sync(tabletB);

    expect(first.stockAdjustments).toEqual([]);
    expect(colaStock(first)).toBe(72);
    expect(colaStock(second)).toBe(72);
    expect(prisma.stockAdjustment.rows[0]).toMatchObject({ status: 'applied', stockAfter: 72 });
  });

  it('records results from older tablets that applied an adjustment themselves', async () => {
    const { sync, tabletA, prisma } = setupWithCola();
    await trackedCola(sync, tabletA);
    const id = uuidv4();
    prisma.stockAdjustment.rows.push({
      id, venueId: 'v1', productId: 'cola', productName: 'Cola', type: 'add', quantity: 24, status: 'pending', createdAt: new Date(),
    });

    const result = await sync(tabletA, { stockAdjustmentResults: [{ id, status: 'applied', stockAfter: 72 }] });

    expect(result.acknowledgedStockAdjustmentResultIds).toEqual([id]);
    // Applied by the tablet, so not again by the server
    expect(colaStock(result)).toBe(48);
  });

});

describe('DevicesService.sync live update signals', () => {
  it('sends nothing when the sync changed nothing', async () => {
    const { sync, tabletA, realtime } = setup();
    await sync(tabletA, { products: catalog(), events: [events.opened('t1', 'Alice')] });
    realtime.notify.mockClear();

    await sync(tabletA, { products: catalog() });

    expect(realtime.notify).not.toHaveBeenCalled();
  });

  it('signals "tabs" and "stock" when they changed', async () => {
    const { sync, tabletA, realtime, prisma } = setup();
    addProduct(prisma);

    await sync(tabletA, { events: [events.opened('t1', 'Alice'), events.stockSet('cola', 5)] });

    expect(realtime.notify).toHaveBeenCalledWith('v1', 'tabs', 'stock');
  });

  it('signals "device" when a terminal comes back online', async () => {
    const { sync, realtime } = setup();

    await sync({ id: 'd1', venueId: 'v1', revokedAt: null, lastSeenAt: new Date(Date.now() - 3_600_000) });

    expect(realtime.notify).toHaveBeenCalledWith('v1', 'device');
  });
});

describe('DevicesService.sync: website product changes reach the tablets', () => {
  const admin = { id: 'u1', email: 'admin@example.com', name: 'Admin' };

  function setupWithWebsite() {
    const venue = setup();
    const stock = new StockService(venue.prisma as any, { log: jest.fn() } as any, { notify: jest.fn() } as any);
    return { ...venue, stock };
  }

  it('sends a new price to every tablet in its next sync', async () => {
    const { sync, tabletA, tabletB, stock, prisma } = setupWithWebsite();
    addProduct(prisma);

    await stock.updateProduct('v1', 'cola', { priceInCents: 270 }, admin);
    const a = await sync(tabletA);
    const b = await sync(tabletB);

    for (const result of [a, b]) {
      expect(result.catalog).toEqual([expect.objectContaining({ id: 'cola', priceInCents: 270 })]);
    }
  });

  it('keeps old drinks at their price and puts new ones on a new line', async () => {
    const { sync, tabletA, tabletB, stock, prisma } = setupWithWebsite();
    addProduct(prisma);
    await sync(tabletA, {
      events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 2, { lineId: 'old-line' })],
    });

    await stock.updateProduct('v1', 'cola', { priceInCents: 270 }, admin);
    // The tablet charges the new price on a line of its own
    const result = await sync(tabletB, {
      events: [events.line('line_added', 't1', 1, { lineId: 'new-line', price: 270, minutes: 5 })],
    });

    expect(tab(result, 't1')!.lines.map((l) => [l.id, l.unitPriceInCents, l.quantity])).toEqual([
      ['old-line', 250, 2],
      ['new-line', 270, 1],
    ]);
  });

  it('settles every line at its own price', async () => {
    const { sync, tabletA, prisma } = setupWithWebsite();
    addProduct(prisma);
    const settled = {
      ...events.settled('t1', 0, 10),
      amountInCents: 2 * 250 + 270,
      items: [
        { productId: 'cola', productName: 'Cola', quantity: 2, unitPriceInCents: 250 },
        { productId: 'cola', productName: 'Cola', quantity: 1, unitPriceInCents: 270 },
      ],
    };

    const result = await sync(tabletA, {
      events: [
        events.opened('t1', 'Alice'),
        events.line('line_added', 't1', 2, { lineId: 'old-line' }),
        events.line('line_added', 't1', 1, { lineId: 'new-line', price: 270, minutes: 5 }),
        settled,
      ],
    });

    expect(tab(result, 't1')!.lines).toEqual([]);
    expect(result.settlements[0].lines.map((l) => [l.unitPriceInCents, l.quantity])).toEqual([[250, 2], [270, 1]]);
  });

  it('counts both price lines down from the one product stock', async () => {
    const { sync, tabletA, stock, prisma } = setupWithWebsite();
    addProduct(prisma, 'cola', { stock: 20, countedAt: new Date('2026-01-01') });

    await sync(tabletA, { events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 2)] });
    await stock.updateProduct('v1', 'cola', { priceInCents: 270 }, admin);
    const result = await sync(tabletA, {
      events: [events.line('line_added', 't1', 1, { lineId: 'new-line', price: 270, minutes: 5 })],
    });

    expect(colaStock(result)).toBe(17);
  });

  it('sends a product added on the website with its starting stock', async () => {
    const { sync, tabletA, stock } = setupWithWebsite();

    const created = await stock.createProduct('v1', { name: 'Ice Tea', category: 'Frisdrank', priceInCents: 280, stock: 24 }, admin);
    const result = await sync(tabletA);

    expect(result.catalog).toEqual([expect.objectContaining({ id: created.productId, name: 'Ice Tea', priceInCents: 280 })]);
    expect(result.stock).toEqual([expect.objectContaining({ productId: created.productId, stock: 24 })]);
  });

  it('marks an archived product, and still counts a sale from a tablet that had not synced yet', async () => {
    const { sync, tabletA, stock, prisma } = setupWithWebsite();
    addProduct(prisma, 'cola', { stock: 20, countedAt: new Date('2026-01-01') });

    await stock.updateProduct('v1', 'cola', { archived: true }, admin);
    const result = await sync(tabletA, {
      events: [events.opened('t1', 'Alice'), events.line('line_added', 't1', 1, { minutes: 1 })],
    });

    expect(result.catalog).toEqual([expect.objectContaining({ id: 'cola', archived: true })]);
    expect(tab(result, 't1')!.lines).toMatchObject([{ productId: 'cola', quantity: 1 }]);
    expect(colaStock(result)).toBe(19);
  });

  it('a renamed product keeps its id, so tablets update it instead of adding one', async () => {
    const { sync, tabletA, stock, prisma } = setupWithWebsite();
    addProduct(prisma);

    await stock.updateProduct('v1', 'cola', { name: 'Coca-Cola' }, admin);
    const result = await sync(tabletA);

    expect(result.catalog).toEqual([expect.objectContaining({ id: 'cola', name: 'Coca-Cola' })]);
  });
});

describe('DevicesService.sync: products created and changed on a tablet', () => {
  const admin = { id: 'u1', email: 'admin@example.com', name: 'Admin' };

  function setupWithWebsite() {
    const venue = setup();
    const stock = new StockService(venue.prisma as any, { log: jest.fn() } as any, { notify: jest.fn() } as any);
    return { ...venue, stock };
  }

  const catalogEntry = (result: SyncResult, id: string) => result.catalog.find((p) => p.id === id);

  it('creates a product made offline, and sells and counts it in the same sync', async () => {
    const { sync, tabletA, tabletB } = setup();

    await sync(tabletA, {
      events: [
        events.product('product_created', 'iced', { name: 'Ice Coffee', category: 'Koffie', priceInCents: 350, lowStockThreshold: 3 }, 1),
        events.stockSet('iced', 12, 2),
        events.opened('t1', 'Alice', 3),
        events.line('line_added', 't1', 2, { minutes: 4, productId: 'iced', productName: 'Ice Coffee', price: 350 }),
      ],
    });
    const result = await sync(tabletB);

    expect(catalogEntry(result, 'iced')).toEqual(
      { id: 'iced', name: 'Ice Coffee', category: 'Koffie', priceInCents: 350, lowStockThreshold: 3, archived: false, imageId: null });
    expect(result.stock.find((s) => s.productId === 'iced')?.stock).toBe(10);
  });

  it('keeps both a website price change and an offline rename of the same product', async () => {
    const { sync, tabletA, stock, prisma } = setupWithWebsite();
    await sync(tabletA, { events: [events.product('product_created', 'cola', { name: 'Cola', priceInCents: 250 }, 0)] });

    await stock.updateProduct('v1', 'cola', { priceInCents: 270 }, admin);
    // Renamed offline before the price change, synced after it
    const result = await sync(tabletA, { events: [events.product('product_updated', 'cola', { name: 'Coca-Cola' }, 5)] });

    expect(catalogEntry(result, 'cola')).toMatchObject({ name: 'Coca-Cola', priceInCents: 270 });
    expect(prisma.product.rows[0].fieldUpdatedAt).toMatchObject({ name: at(5) });
  });

  it('lets the latest change of a field win, also when the older one arrives last', async () => {
    const { sync, tabletA, tabletB } = setup();
    await sync(tabletA, { events: [events.product('product_created', 'cola', { name: 'Cola', priceInCents: 250 }, 0)] });

    await sync(tabletB, { events: [events.product('product_updated', 'cola', { priceInCents: 300 }, 20)] });
    // Tablet A was offline: its older price change arrives later and loses
    const result = await sync(tabletA, { events: [events.product('product_updated', 'cola', { priceInCents: 280 }, 10)] });

    expect(catalogEntry(result, 'cola')!.priceInCents).toBe(300);
  });

  it('a website change made after a tablet change wins', async () => {
    const { sync, tabletA, stock } = setupWithWebsite();
    await sync(tabletA, { events: [events.product('product_created', 'cola', { name: 'Cola', priceInCents: 250 }, 0)] });
    await sync(tabletA, { events: [events.product('product_updated', 'cola', { priceInCents: 280 }, 1)] });

    await stock.updateProduct('v1', 'cola', { priceInCents: 260 }, admin);
    const result = await sync(tabletA);

    expect(catalogEntry(result, 'cola')!.priceInCents).toBe(260);
  });

  it('archives and restores a product from a tablet', async () => {
    const { sync, tabletA } = setup();
    await sync(tabletA, { events: [events.product('product_created', 'cola', { name: 'Cola', priceInCents: 250 }, 0)] });

    const archived = await sync(tabletA, { events: [events.product('product_archived', 'cola', undefined, 1)] });
    expect(catalogEntry(archived, 'cola')!.archived).toBe(true);

    const restored = await sync(tabletA, { events: [events.product('product_restored', 'cola', undefined, 2)] });
    expect(catalogEntry(restored, 'cola')!.archived).toBe(false);
  });

  it('only links a picture that was uploaded', async () => {
    const { sync, tabletA, prisma } = setup();
    prisma.productImage.rows.push({ id: 'a'.repeat(64), contentType: 'image/webp', width: 512, height: 512, bytes: Buffer.from('x') });
    await sync(tabletA, { events: [events.product('product_created', 'cola', { name: 'Cola', priceInCents: 250 }, 0)] });

    const unknown = await sync(tabletA, { events: [events.product('product_updated', 'cola', { imageId: 'b'.repeat(64) }, 1)] });
    expect(catalogEntry(unknown, 'cola')!.imageId).toBeNull();

    const known = await sync(tabletA, { events: [events.product('product_updated', 'cola', { imageId: 'a'.repeat(64) }, 2)] });
    expect(catalogEntry(known, 'cola')!.imageId).toBe('a'.repeat(64));

    const removed = await sync(tabletA, { events: [events.product('product_updated', 'cola', { imageId: null }, 3)] });
    expect(catalogEntry(removed, 'cola')!.imageId).toBeNull();
  });

  it('accepts two products with the same name from two offline tablets', async () => {
    const { sync, tabletA, tabletB } = setup();

    await sync(tabletA, { events: [events.product('product_created', 'cola-a', { name: 'Cola', priceInCents: 250 }, 0)] });
    const result = await sync(tabletB, { events: [events.product('product_created', 'cola-b', { name: 'cola', priceInCents: 250 }, 0)] });

    expect(result.catalog.map((p) => p.id).sort()).toEqual(['cola-a', 'cola-b']);
  });

  it('acknowledges a change to a product the venue does not have, without creating it', async () => {
    const { sync, tabletA } = setup();
    const change = events.product('product_updated', 'gone', { name: 'Gone' }, 0);

    const result = await sync(tabletA, { events: [change] });

    expect(result.acknowledgedEventIds).toEqual([change.id]);
    expect(result.catalog).toEqual([]);
  });

  it('rejects a new product without a price', async () => {
    const { sync, tabletA } = setup();
    const incomplete = events.product('product_created', 'x', { name: 'X' }, 0);

    const result = await sync(tabletA, { events: [incomplete] });

    expect(result.rejectedEvents).toEqual([{ id: incomplete.id, reason: 'a new product needs a name and a price' }]);
  });

  it('applies a product event once, also when it is sent again', async () => {
    const { sync, tabletA, tabletB } = setup();
    const created = events.product('product_created', 'cola', { name: 'Cola', priceInCents: 250 }, 0);
    const renamed = events.product('product_updated', 'cola', { name: 'Coca-Cola' }, 1);
    await sync(tabletA, { events: [created, renamed] });
    await sync(tabletB, { events: [events.product('product_updated', 'cola', { name: 'Cola Classic' }, 2)] });

    // The old rename again, with its id: already applied, so it must not undo the newer name
    const result = await sync(tabletA, { events: [renamed] });

    expect(catalogEntry(result, 'cola')!.name).toBe('Cola Classic');
  });
});