Enforce unique product barcodes

src/components/ProductRow.tsx

@@ -50,28 +50,41 @@ export const ProductRow = ({ product, categories, onSave, onDelete }: ProductRow
   const [isEditing, setIsEditing] = useState(false);
   const [formState, setFormState] = useState<ProductFormState>(() => getInitialFormState(product));
   const [isScannerOpen, setIsScannerOpen] = useState(false);
+  const [saveError, setSaveError] = useState('');
 
   useEffect(() => {
     setFormState(getInitialFormState(product));
+    setSaveError('');
   }, [product]);
 
   const handleChange = (field: keyof ProductFormState) => (event: ChangeEvent<HTMLInputElement>) => {
     setFormState((prev) => ({ ...prev, [field]: event.target.value }));
+    setSaveError('');
   };
 
   const handleSave = async () => {
     if (!formState.name) return;
-    await onSave(product.id, {
+    try {
-      name: formState.name,
+      await onSave(product.id, {
-      category: formState.category,
+        name: formState.name,
-      barcode: formState.barcode || undefined,
+        category: formState.category,
-    });
+        barcode: formState.barcode || undefined,
-    setIsEditing(false);
+      });
+      setIsEditing(false);
+      setSaveError('');
+    } catch (error) {
+      if (error instanceof Error && error.name === 'DuplicateBarcodeError') {
+        setSaveError('This barcode is already assigned to another product.');
+        return;
+      }
+      throw error;
+    }
   };
 
   const handleCancel = () => {
     setIsEditing(false);
     setFormState(getInitialFormState(product));
+    setSaveError('');
   };
 
   return (
@@ -99,9 +112,17 @@ export const ProductRow = ({ product, categories, onSave, onDelete }: ProductRow
                 value={formState.barcode}
                 onChange={handleChange('barcode')}
                 size="small"
+                error={Boolean(saveError)}
+                helperText={saveError || undefined}
                 InputProps={{
                   endAdornment: (
-                    <Button size="small" onClick={() => setFormState((prev) => ({ ...prev, barcode: '' }))}>
+                    <Button
+                      size="small"
+                      onClick={() => {
+                        setFormState((prev) => ({ ...prev, barcode: '' }));
+                        setSaveError('');
+                      }}
+                    >
                       Clear
                     </Button>
                   ),

src/db/index.ts

@@ -51,6 +51,45 @@ export class StockFillDB extends Dexie {
           })),
         );
       });
+
+    this.version(3)
+      .stores({
+        products:
+          'id, name, category, barcode, archived, created_at, updated_at',
+        areas: 'id, name, created_at, updated_at',
+        pickLists: 'id, area_id, created_at, completed_at',
+        pickItems: 'id, pick_list_id, product_id, status, created_at, updated_at',
+        categories: 'id, name, created_at, updated_at',
+      })
+      .upgrade(async (tx) => {
+        const products = await tx.table('products').toArray();
+        const seenBarcodes = new Set<string>();
+        const now = Date.now();
+
+        await Promise.all(
+          products.map((product) => {
+            if (!product.barcode) return undefined;
+
+            if (seenBarcodes.has(product.barcode)) {
+              return tx.table('products').update(product.id, {
+                barcode: undefined,
+                updated_at: now,
+              });
+            }
+
+            seenBarcodes.add(product.barcode);
+            return undefined;
+          }),
+        );
+      });
+
+    this.version(4).stores({
+      products: 'id, name, category, &barcode, archived, created_at, updated_at',
+      areas: 'id, name, created_at, updated_at',
+      pickLists: 'id, area_id, created_at, completed_at',
+      pickItems: 'id, pick_list_id, product_id, status, created_at, updated_at',
+      categories: 'id, name, created_at, updated_at',
+    });
   }
 }
 

src/screens/ManageProductsScreen.test.tsx

@@ -1,29 +1,36 @@
 import { http, HttpResponse } from 'msw';
 import { setupServer } from 'msw/node';
 import { MemoryRouter } from 'react-router-dom';
-import { render, screen, waitFor } from '@testing-library/react';
+import { fireEvent, render, screen, waitFor, waitForElementToBeRemoved } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
-import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from 'vitest';
+import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, vi } from 'vitest';
 import { ManageProductsScreen } from './ManageProductsScreen';
 
+let mockScannedBarcode = '123456';
+const mockUseProducts = vi.fn();
+const mockUseCategories = vi.fn();
+
+const mockDb = {
+  products: {
+    add: vi.fn(),
+    update: vi.fn(),
+    delete: vi.fn(),
+    where: vi.fn(),
+  },
+};
+
 vi.mock('../hooks/dataHooks', () => ({
-  useProducts: () => [],
+  useProducts: () => mockUseProducts(),
-  useCategories: () => [{ id: 'cat-1', name: 'Snacks', created_at: 0, updated_at: 0 }],
+  useCategories: () => mockUseCategories(),
 }));
 
 vi.mock('../context/DBProvider', () => ({
-  useDatabase: () => ({
+  useDatabase: () => mockDb,
-    products: {
-      add: vi.fn(),
-      update: vi.fn(),
-      delete: vi.fn(),
-    },
-  }),
 }));
 
 vi.mock('../components/BarcodeScannerView', () => ({
   BarcodeScannerView: ({ onDetected }: { onDetected?: (code: string) => void }) => (
-    <button type="button" onClick={() => onDetected?.('123456')}>
+    <button type="button" onClick={() => onDetected?.(mockScannedBarcode)}>
       Mock Scan
     </button>
   ),
@@ -36,6 +43,18 @@ describe('ManageProductsScreen barcode lookup', () => {
   afterEach(() => server.resetHandlers());
   afterAll(() => server.close());
 
+  beforeEach(() => {
+    mockUseProducts.mockReturnValue([]);
+    mockUseCategories.mockReturnValue([{ id: 'cat-1', name: 'Snacks', created_at: 0, updated_at: 0 }]);
+    mockScannedBarcode = '123456';
+    Object.values(mockDb.products).forEach((fn) => fn.mockReset());
+    mockDb.products.where.mockImplementation(() => ({
+      equals: (value: string) => ({
+        first: () => Promise.resolve(mockUseProducts().find((product: any) => product.barcode === value)),
+      }),
+    }));
+  });
+
   it('prefills the product name after scanning a barcode', async () => {
     server.use(
       http.get('https://world.openfoodfacts.org/api/v2/product/123456.json', () =>
@@ -62,5 +81,83 @@ describe('ManageProductsScreen barcode lookup', () => {
       expect(screen.getByLabelText(/name/i)).toHaveValue('OFF Test Product');
     });
   });
+
+  it('prevents adding a product with a duplicate barcode', async () => {
+    mockUseProducts.mockReturnValue([
+      {
+        id: 'prod-1',
+        name: 'Existing Product',
+        category: 'Snacks',
+        barcode: '123456',
+        unit_type: 'unit',
+        bulk_name: 'pack',
+        archived: false,
+        created_at: 0,
+        updated_at: 0,
+      },
+    ]);
+
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <ManageProductsScreen />
+      </MemoryRouter>,
+    );
+
+    await user.type(screen.getByLabelText(/name/i), 'New Product');
+    await user.click(screen.getByRole('button', { name: /scan barcode/i }));
+    await user.click(screen.getByRole('button', { name: /mock scan/i }));
+    await waitForElementToBeRemoved(() => screen.queryByRole('dialog', { name: /scan barcode/i }));
+    await user.click(screen.getByRole('button', { name: /save product/i }));
+
+    expect(await screen.findByText(/barcode is already assigned/i)).toBeVisible();
+    expect(mockDb.products.add).not.toHaveBeenCalled();
+  });
+
+  it('prevents updating a product to use an existing barcode', async () => {
+    mockUseProducts.mockReturnValue([
+      {
+        id: 'prod-1',
+        name: 'Existing Product',
+        category: 'Snacks',
+        barcode: '123456',
+        unit_type: 'unit',
+        bulk_name: 'pack',
+        archived: false,
+        created_at: 0,
+        updated_at: 0,
+      },
+      {
+        id: 'prod-2',
+        name: 'Another Product',
+        category: 'Snacks',
+        barcode: '654321',
+        unit_type: 'unit',
+        bulk_name: 'pack',
+        archived: false,
+        created_at: 0,
+        updated_at: 0,
+      },
+    ]);
+
+    const user = userEvent.setup();
+    render(
+      <MemoryRouter>
+        <ManageProductsScreen />
+      </MemoryRouter>,
+    );
+
+    await user.click(screen.getByLabelText(/edit existing product/i));
+    const barcodeField = screen.getByLabelText(/barcode/i);
+    fireEvent.change(barcodeField, { target: { value: '654321' } });
+    expect(barcodeField).toHaveValue('654321');
+    await user.click(screen.getByLabelText(/save product/i));
+
+    await waitFor(() => {
+      expect(barcodeField).toHaveAccessibleDescription('This barcode is already assigned to another product.');
+      expect(barcodeField).toHaveAttribute('aria-invalid', 'true');
+    });
+    expect(mockDb.products.update).not.toHaveBeenCalled();
+  });
 });
 

src/screens/ManageProductsScreen.tsx

@@ -30,6 +30,7 @@ export const ManageProductsScreen = () => {
   const [name, setName] = useState('');
   const [category, setCategory] = useState('');
   const [barcode, setBarcode] = useState('');
+  const [barcodeError, setBarcodeError] = useState('');
   const [scannerOpen, setScannerOpen] = useState(false);
   const [lookupStatus, setLookupStatus] = useState<'idle' | 'loading' | 'found' | 'notfound' | 'offline'>(
     'idle',
@@ -66,6 +67,30 @@ export const ManageProductsScreen = () => {
     return Array.from(new Set([...categoryNames, ...productCategories]));
   }, [categories, products]);
 
+  const findBarcodeConflict = useCallback(
+    (value?: string, productId?: string) =>
+      value
+        ? products.find((product) => product.barcode === value && product.id !== productId)
+        : undefined,
+    [products],
+  );
+
+  const assertUniqueBarcode = useCallback(
+    async (value?: string, productId?: string) => {
+      if (!value) return;
+
+      const conflict =
+        findBarcodeConflict(value, productId) ?? (await db.products.where('barcode').equals(value).first());
+
+      if (conflict && conflict.id !== productId) {
+        const error = new Error('This barcode is already assigned to another product.');
+        error.name = 'DuplicateBarcodeError';
+        throw error;
+      }
+    },
+    [db.products, findBarcodeConflict],
+  );
+
   useEffect(() => {
     if (categoryOptions.length === 0) return;
     if (!categoryOptions.includes(category)) {
@@ -94,10 +119,22 @@ export const ManageProductsScreen = () => {
       setLookupStatus('idle');
       setExternalProduct(null);
     }
+    setBarcodeError('');
   }, [barcode]);
 
   const addProduct = async () => {
     if (!name || !category) return;
+
+    try {
+      await assertUniqueBarcode(barcode || undefined);
+    } catch (error) {
+      if (error instanceof Error && error.name === 'DuplicateBarcodeError') {
+        setBarcodeError(error.message);
+        return;
+      }
+      throw error;
+    }
+
     await db.products.add({
       id: uuidv4(),
       name,
@@ -121,6 +158,8 @@ export const ManageProductsScreen = () => {
       barcode?: string;
     },
   ) => {
+    await assertUniqueBarcode(updates.barcode, productId);
+
     await db.products.update(productId, {
       ...updates,
       unit_type: DEFAULT_UNIT_TYPE,
@@ -185,6 +224,8 @@ export const ManageProductsScreen = () => {
                 label="Barcode"
                 value={barcode}
                 onChange={(event) => setBarcode(event.target.value)}
+                error={Boolean(barcodeError)}
+                helperText={barcodeError || undefined}
                 InputProps={{
                   endAdornment: (
                     <Button onClick={() => setBarcode('')} size="small">