# Data Model: Product Selection Landing Page

**Feature**: 002-product-list | **Date**: 2025-10-17

## Overview

This feature reuses the existing **Product** entity from feature 001-build-an-application with a minor extension. No new entities are created.

## Existing Entity: Product

**Source**: `app/models/product.py` (from feature 001)

**Attributes** (relevant to this feature):

| Attribute | Type | Required | Description |
|-----------|------|----------|-------------|
| `product_id` | str | Yes | Unique identifier (e.g., "001-acme-app") |
| `name` | str | Yes | Display name for the product |
| `submission_url_slug` | str | Yes | URL segment for submission form |
| `status` | str | Yes | "active" or "archived" |
| `description` | str | No | Brief product description (optional) |

**Storage**: File-based YAML at `data/products/{product-id}/config.yaml`

**Example**:
```yaml
product_id: "001-acme-app"
name: "Acme Application"
submission_url_slug: "acme-app"
status: "active"
description: "Enterprise resource planning system"
```

---

## Model Extension

### New Class Method: `load_active()`

**Purpose**: Load and return only active products with valid submission URLs, sorted for display.

**Signature**:
```python
@classmethod
def load_active(cls) -> list[Product]:
    """Load all active products, sorted alphabetically by name then product_id."""
```

**Returns**: List of Product instances where:
- `status == 'active'`
- `submission_url_slug` is present and valid
- Sorted by: `(name.lower(), product_id)`

**Implementation Location**: `app/models/product.py`

**Usage Example**:
```python
from app.models.product import Product

# In route handler
products = Product.load_active()
# Returns sorted list of active products ready for display
```

---

## Data Flow

### Landing Page Load Sequence

1. **Request**: User navigates to `/`
2. **Route Handler**: `app/routes/landing.py`
   - Calls `Product.load_active()`
3. **Data Loading**: Product model
   - Reads all `data/products/*/config.yaml` files
   - Filters: `status == 'active'` AND `submission_url_slug` exists
   - Sorts: By `(name.lower(), product_id)`
4. **Response**: Render template with product list
   - Pass `products` to `templates/landing/index.html`
   - Template loops over products, displays name/description/link

### Diagram

```
User → GET / → landing.py → Product.load_active() → [Product, Product, ...]
                                  ↓
                            Templates (Jinja2) → HTML Response → User
```

---

## Validation Rules

### Product Visibility (for landing page)

A product is **visible** on the landing page if and only if:
1. `status == 'active'` (FR-003)
2. `submission_url_slug` is not None/empty (FR-015)

Products failing either condition are **excluded** from the list.

### Sorting Rules (FR-009)

Products are sorted by:
1. **Primary**: `name` (case-insensitive alphabetical)
2. **Secondary**: `product_id` (alphabetical, for ties)

**Examples**:
- Input: `[{"name": "Zebra", "product_id": "001"}, {"name": "Apple", "product_id": "002"}]`
- Output: `[{"name": "Apple", ...}, {"name": "Zebra", ...}]`

- Input: `[{"name": "App", "product_id": "002"}, {"name": "App", "product_id": "001"}]`
- Output: `[{"name": "App", "product_id": "001"}, {"name": "App", "product_id": "002"}]`

---

## No New Entities

This feature introduces **no new entities**. All data structures are reused from feature 001:
- Product entity (extended with `load_active()` method only)
- File-based YAML storage (unchanged)
- No database tables, no new data files

---

## Testing Considerations

### Test Data Requirements

For comprehensive testing, create products with:
- Various statuses: "active", "archived"
- With/without descriptions
- With/without valid `submission_url_slug`
- Duplicate names (to test secondary sort)
- Various name cases ("Apple", "apple", "APPLE")

### Expected Behaviors

| Scenario | Expected Result |
|----------|----------------|
| Product with `status: active` | Included in list |
| Product with `status: archived` | Excluded from list |
| Product with missing `submission_url_slug` | Excluded from list |
| Products with same name | Sorted by product_id |
| Empty product directory | Returns empty list |

**Reference Tests**: See `tests/contract/test_landing_routes.py` for data model validation tests.