# Phase 5 — Product Library

**Goal**: A searchable catalog of food products with nutrition data, reusable across the entire food tracking domain. Products are the atomic building blocks for recipes, pantry items, and shopping lists.

**Depends on**: Phase 0 (auth, households, shared types). Can reuse Store infrastructure from Phase 4.

---

## Deliverables

1. `Product` MongoDB schema and full CRUD API
2. Full-text search with filters
3. Barcode lookup via Open Food Facts
4. Bulk import (CSV/JSON)
5. Product library web UI (search, add, edit)
6. LLM provider interface (`ILlmProvider`) with no-op implementation
7. "Smart Add" endpoint placeholder

---

## Data Model

### Product Schema

```typescript
// packages/shared/src/types/product.ts
export interface Product {
  id: string;
  householdId: string;
  name: string;
  brand?: string;
  barcode?: string;
  category: ProductCategory;
  servingSize: number;
  servingUnit: ServingUnit;
  nutrition: NutritionInfo;
  tags: string[];
  imageUrl?: string;
  isPublic: boolean; // Visible to all households (for shared catalog)
  source: ProductSource; // 'manual' | 'barcode_lookup' | 'llm' | 'import'
  createdBy: string; // userId
  createdAt: Date;
  updatedAt: Date;
}

export interface NutritionInfo {
  calories: number; // kcal per serving
  protein: number; // grams
  carbs: number; // grams
  fat: number; // grams
  fiber?: number; // grams
  sugar?: number; // grams
  sodium?: number; // mg
  saturatedFat?: number; // grams
  cholesterol?: number; // mg
}

export enum ProductCategory {
  DAIRY = 'dairy',
  MEAT = 'meat',
  POULTRY = 'poultry',
  SEAFOOD = 'seafood',
  FRUITS = 'fruits',
  VEGETABLES = 'vegetables',
  GRAINS = 'grains',
  LEGUMES = 'legumes',
  NUTS_SEEDS = 'nuts_seeds',
  OILS_FATS = 'oils_fats',
  CONDIMENTS = 'condiments',
  SPICES = 'spices',
  BEVERAGES = 'beverages',
  SNACKS = 'snacks',
  FROZEN = 'frozen',
  CANNED = 'canned',
  BAKERY = 'bakery',
  DELI = 'deli',
  SUPPLEMENTS = 'supplements',
  OTHER = 'other',
}

export enum ServingUnit {
  GRAMS = 'g',
  MILLILITERS = 'ml',
  OUNCES = 'oz',
  CUPS = 'cup',
  TABLESPOONS = 'tbsp',
  TEASPOONS = 'tsp',
  PIECES = 'piece',
  SLICES = 'slice',
}

export enum ProductSource {
  MANUAL = 'manual',
  BARCODE_LOOKUP = 'barcode_lookup',
  LLM = 'llm',
  IMPORT = 'import',
}
```

### MongoDB Indexes

```javascript
// Text index for search
{ name: 'text', brand: 'text', tags: 'text' }

// Compound indexes
{ householdId: 1, category: 1 }
{ householdId: 1, barcode: 1 }       // unique within household
{ householdId: 1, name: 1, brand: 1 } // near-unique for dedup
```

---

## API Endpoints

### ProductsModule

| Method | Path                      | Description                                 | Auth   |
| ------ | ------------------------- | ------------------------------------------- | ------ |
| GET    | `/products`               | List/search products (paginated)            | member |
| GET    | `/products/:id`           | Get single product                          | member |
| POST   | `/products`               | Create product                              | member |
| PATCH  | `/products/:id`           | Update product                              | member |
| DELETE | `/products/:id`           | Soft-delete product                         | admin  |
| GET    | `/products/barcode/:code` | Lookup by barcode (local → Open Food Facts) | member |
| POST   | `/products/import`        | Bulk import from CSV/JSON                   | admin  |
| POST   | `/products/smart-add`     | LLM-powered add from text/image             | member |

### Query Parameters for GET `/products`

```
?q=chicken                    # Full-text search
&category=meat                # Filter by category
&tags=organic,fresh           # Filter by tags (AND)
&cursor=abc123                # Cursor-based pagination
&limit=20                     # Page size (max 100)
&sort=name|-updatedAt         # Sort field, prefix - for desc
```

### Response Shape

```typescript
interface PaginatedResponse<T> {
  data: T[];
  pagination: {
    cursor: string | null; // null = last page
    hasMore: boolean;
    total: number;
  };
}
```

---

## Tasks

### 5.1 — Shared Types & Validation

- Add all types above to `packages/shared/src/types/product.ts`
- Add enums to `packages/shared/src/enums/`
- Create Zod schemas:
  - `CreateProductSchema` — validates create payload
  - `UpdateProductSchema` — partial, validates update payload
  - `ProductQuerySchema` — validates query params

### 5.2 — Mongoose Schema & Repository

- `packages/api/src/modules/products/schemas/product.schema.ts`
- `ProductRepository` with:
  - `findByHousehold(householdId, query)` — supports text search, filters, cursor pagination
  - `findByBarcode(householdId, barcode)`
  - `create(data)`
  - `update(id, householdId, data)`
  - `softDelete(id, householdId)`
  - `bulkCreate(items[])`

### 5.3 — Barcode Lookup Service

- `BarcodeService`:
  - First check local DB for matching barcode
  - If not found, query Open Food Facts API (`https://world.openfoodfacts.org/api/v2/product/{barcode}`)
  - Map OFF response to `Product` shape
  - Cache results in local DB with `source: 'barcode_lookup'`

### 5.4 — LLM Provider Interface

- `packages/api/src/modules/llm/interfaces/llm-provider.interface.ts`:

```typescript
export interface ILlmProvider {
  extractNutrition(input: {
    text?: string;
    image?: Buffer;
  }): Promise<NutritionExtractionResult | null>;
  parseRecipe(text: string): Promise<ParsedRecipe | null>;
  parseRecipeFromUrl(url: string): Promise<ParsedRecipe | null>;
  parseReceipt(image: Buffer): Promise<ParsedReceipt | null>;
  suggestMealPlan(context: MealPlanContext): Promise<MealPlanSuggestion | null>;
  parseNaturalLanguage(text: string): Promise<StructuredAction | null>;
}

export const LLM_PROVIDER = Symbol('LLM_PROVIDER');
```

- `NoOpLlmProvider`: implements interface, returns `null` for all methods, logs a warning
- `LlmModule`: provides `LLM_PROVIDER` via factory, selectable by env var `LLM_PROVIDER_TYPE`

### 5.5 — Smart Add Endpoint

- `POST /products/smart-add` accepts `{ text?: string, image?: file }`
- Calls `ILlmProvider.extractNutrition()`
- If LLM returns data, pre-fill a product and return to client for review (not auto-saved)
- If LLM unavailable (`NoOpLlmProvider`), return `{ available: false, message: 'LLM not configured' }`

### 5.6 — Import Endpoint

- `POST /products/import` accepts multipart CSV or JSON file
- Validate each row against `CreateProductSchema`
- Return summary: `{ imported: N, skipped: M, errors: [...] }`
- CSV column mapping: `name, brand, barcode, category, servingSize, servingUnit, calories, protein, carbs, fat, ...`

### 5.7 — Web UI: Product Library

- `/products` page:
  - Search bar with debounced full-text search
  - Category filter dropdown
  - Tag filter chips
  - Product grid/list view (toggle)
  - Each product card shows: name, brand, category icon, calories/serving
- Add/Edit product modal:
  - Form fields for all product properties
  - Nutrition input section with per-serving values
  - Barcode field with "Lookup" button
  - "Smart Add" tab (text input or image upload)
- Import dialog: file upload with preview and error display

---

## Acceptance Criteria

- [ ] Can create, read, update, delete products via API
- [ ] Full-text search returns relevant results
- [ ] Barcode lookup fetches from Open Food Facts when not in local DB
- [ ] Bulk import processes a CSV with 100+ products
- [ ] Web UI allows searching, filtering, adding, and editing products
- [ ] `ILlmProvider` interface is defined and injectable
- [ ] Smart Add endpoint returns graceful "not available" with NoOp provider
- [ ] All product queries are scoped to `householdId`

---

## Estimated Effort

Medium. Straightforward CRUD with search; barcode integration adds some complexity.