# Phase 7A: Categories - COMPLETE ✅

## Completion Date
December 16, 2024

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## Overview

Phase 7A implements category management with hierarchical structure, product categorization, and full CRUD operations.

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## ✅ Completed Deliverables

### 1. Category Service (`modules/categories/services/index.js`)
- ✅ `createCategory()` - Create category with slug generation
- ✅ `getCategory()` - Get category with parent/children
- ✅ `updateCategory()` - Update category with circular reference prevention
- ✅ `deleteCategory()` - Delete category (validates no children/products)
- ✅ `listCategories()` - List categories with filters and pagination
- ✅ `getCategoryHierarchy()` - Get full category hierarchy (tree structure)
- ✅ `assignProductToCategories()` - Assign product to multiple categories
- ✅ `removeProductFromCategory()` - Remove product from category
- ✅ `getProductCategories()` - Get all categories for a product
- ✅ `generateSlug()` - Generate URL-friendly slugs
- ✅ `checkIfDescendant()` - Prevent circular references

### 2. Category Controllers (`modules/categories/controllers/index.js`)
- ✅ `createCategory` - Create category controller
- ✅ `getCategory` - Get category controller
- ✅ `updateCategory` - Update category controller
- ✅ `deleteCategory` - Delete category controller
- ✅ `listCategories` - List categories controller
- ✅ `getCategoryHierarchy` - Get hierarchy controller
- ✅ `assignProductToCategories` - Assign product to categories controller
- ✅ `removeProductFromCategory` - Remove product from category controller
- ✅ `getProductCategories` - Get product categories controller

### 3. Category Validations (`modules/categories/validations/index.js`)
- ✅ `validateCreateCategory` - Validation for creating categories
- ✅ `validateUpdateCategory` - Validation for updating categories
- ✅ `validateGetCategory` - Validation for getting category
- ✅ `validateDeleteCategory` - Validation for deleting category
- ✅ `validateListCategories` - Validation for listing categories
- ✅ `validateGetCategoryHierarchy` - Validation for hierarchy
- ✅ `validateAssignProductToCategories` - Validation for assignment
- ✅ `validateRemoveProductFromCategory` - Validation for removal
- ✅ `validateGetProductCategories` - Validation for getting product categories

### 4. Category Routes (`modules/categories/routes/index.js`)
- ✅ RESTful endpoints with Swagger documentation
- ✅ All routes integrated into main routes
- ✅ Authentication required
- ✅ Role-based access control

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## 📡 API Endpoints

### Create Category
- **Endpoint:** `POST /api/categories`
- **Auth:** Required (manager, system_admin)
- **Body:**
  ```json
  {
    "name": "Electronics",
    "parent_id": null,
    "description": "Electronic products",
    "image_url": "https://example.com/image.jpg",
    "sort_order": 0
  }
  ```
- **Returns:** Created category

### Get Category by ID
- **Endpoint:** `GET /api/categories/:id`
- **Auth:** Required
- **Returns:** Category with parent and children

### Update Category
- **Endpoint:** `PUT /api/categories/:id`
- **Auth:** Required (manager, system_admin)
- **Body:** Same as create (all fields optional)
- **Returns:** Updated category

### Delete Category
- **Endpoint:** `DELETE /api/categories/:id`
- **Auth:** Required (manager, system_admin)
- **Returns:** Success message
- **Note:** Cannot delete if has children or products

### List Categories
- **Endpoint:** `GET /api/categories?page=1&limit=10&parent_id=null&with_children=false`
- **Auth:** Required
- **Filters:**
  - `parent_id` - Filter by parent ID (use 'null' for root categories)
  - `with_children` - Include child categories (true/false)
- **Returns:** Paginated categories list

### Get Category Hierarchy
- **Endpoint:** `GET /api/categories/hierarchy?root_category_id=1`
- **Auth:** Required
- **Returns:** Full category hierarchy (tree structure)

### Assign Product to Categories
- **Endpoint:** `POST /api/categories/products/:productId`
- **Auth:** Required (manager, system_admin)
- **Body:**
  ```json
  {
    "category_ids": [1, 2, 3],
    "primary_category_id": 1
  }
  ```
- **Returns:** Product-category assignments

### Remove Product from Category
- **Endpoint:** `DELETE /api/categories/products/:productId/:categoryId`
- **Auth:** Required (manager, system_admin)
- **Returns:** Success message

### Get Product Categories
- **Endpoint:** `GET /api/categories/products/:productId`
- **Auth:** Required
- **Returns:** All categories for product

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## 🔑 Key Features

### Hierarchical Categories
- **Parent-child relationships** for category hierarchy
- **Tree structure** support
- **Circular reference prevention** when updating parent
- **Slug generation** from category names

### Product Categorization
- **Multiple categories** per product
- **Primary category** designation
- **Many-to-many** relationship via ProductCategory junction table

### Category Management
- **CRUD operations** for categories
- **Hierarchical navigation** with parent/children
- **Sort order** for display
- **Slug generation** for URL-friendly identifiers

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## 📊 Database Schema

### Category Table
- `id` - Primary key
- `name` - Category name (required)
- `slug` - URL-friendly identifier (unique, optional)
- `parent_id` - Foreign key to categories (self-referential, optional)
- `description` - Category description (optional)
- `image_url` - Category image URL (optional)
- `sort_order` - Sort order for display

### ProductCategory Table
- `id` - Primary key
- `product_id` - Foreign key to products
- `category_id` - Foreign key to categories
- `is_primary` - Primary category flag

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## 📝 Business Rules

1. **Category Creation:**
   - Name is required
   - Slug auto-generated if not provided
   - Parent category validated if provided
   - Sort order defaults to 0

2. **Category Updates:**
   - Cannot set category as its own parent
   - Cannot create circular references
   - Slug regenerated if name changes

3. **Category Deletion:**
   - Cannot delete if has child categories
   - Cannot delete if has assigned products

4. **Product Assignment:**
   - Product can be in multiple categories
   - One primary category per product
   - Primary category flag updated automatically

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## ✅ Acceptance Criteria Met

- ✅ Categories work hierarchically
- ✅ Products can be in multiple categories
- ✅ Category CRUD operations working
- ✅ Hierarchy tree structure working
- ✅ Circular reference prevention working
- ✅ Slug generation working

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## 📦 Dependencies

- `slugify` - For slug generation (installed)

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## 🚀 Next Steps

Phase 7B: Pricing
- Implement price list service (CRUD)
- Implement product price service
- Implement price lookup logic
- Integrate pricing into sales

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**Phase 7A Status: COMPLETE ✅**

