# Small Business Inventory Management System

A comprehensive inventory management API built with FastAPI and SQLAlchemy for small businesses. This API provides functionality to manage products, inventory, suppliers, and purchases.

## Features

- **Product Management**: CRUD operations for products and categories
- **Inventory Management**: Track inventory levels across multiple locations
- **Supplier Management**: Manage suppliers and their contact information
- **Purchase Management**: Create and track purchase orders
- **Transaction Tracking**: Record and track inventory movements (sales, purchases, transfers, adjustments)
- **Stock Alerts**: Monitor low-stock items

## Tech Stack

- **FastAPI**: High-performance web framework for building APIs
- **SQLAlchemy**: SQL toolkit and ORM
- **Pydantic**: Data validation and settings management
- **Alembic**: Database migration tool
- **SQLite**: Lightweight database

## Getting Started

### Prerequisites

- Python 3.8+
- pip

### Installation

1. Clone the repository
```bash
git clone <repository-url>
cd smallbusinessinventorymanagementsystem
```

2. Install dependencies
```bash
pip install -r requirements.txt
```

3. Run the application
```bash
uvicorn main:app --reload
```

4. Access the API documentation at http://localhost:8000/docs

## API Endpoints

The API is organized around the following main resources:

### Products & Categories

- `GET /api/v1/products/`: List all products
- `POST /api/v1/products/`: Create a new product
- `GET /api/v1/products/{product_id}`: Get product details
- `PUT /api/v1/products/{product_id}`: Update a product
- `DELETE /api/v1/products/{product_id}`: Delete a product

- `GET /api/v1/categories/`: List all categories
- `POST /api/v1/categories/`: Create a new category
- `GET /api/v1/categories/{category_id}`: Get category details
- `PUT /api/v1/categories/{category_id}`: Update a category
- `DELETE /api/v1/categories/{category_id}`: Delete a category

### Inventory Management

- `GET /api/v1/inventory/`: List inventory items
- `POST /api/v1/inventory/`: Create inventory item
- `GET /api/v1/inventory/{item_id}`: Get inventory item details
- `PUT /api/v1/inventory/{item_id}`: Update inventory item
- `DELETE /api/v1/inventory/{item_id}`: Delete inventory item

- `GET /api/v1/locations/`: List all locations
- `POST /api/v1/locations/`: Create a new location
- `GET /api/v1/locations/{location_id}`: Get location details
- `PUT /api/v1/locations/{location_id}`: Update a location
- `DELETE /api/v1/locations/{location_id}`: Delete a location

- `GET /api/v1/inventory-transactions/`: List inventory transactions
- `POST /api/v1/inventory-transactions/`: Create inventory transaction
- `GET /api/v1/inventory-transactions/{transaction_id}`: Get transaction details

### Suppliers & Purchases

- `GET /api/v1/suppliers/`: List all suppliers
- `POST /api/v1/suppliers/`: Create a new supplier
- `GET /api/v1/suppliers/{supplier_id}`: Get supplier details
- `PUT /api/v1/suppliers/{supplier_id}`: Update a supplier
- `DELETE /api/v1/suppliers/{supplier_id}`: Delete a supplier

- `GET /api/v1/purchases/`: List all purchases
- `POST /api/v1/purchases/`: Create a new purchase
- `GET /api/v1/purchases/{purchase_id}`: Get purchase details
- `PUT /api/v1/purchases/{purchase_id}`: Update a purchase
- `DELETE /api/v1/purchases/{purchase_id}`: Delete a purchase
- `POST /api/v1/purchases/{purchase_id}/receive`: Receive purchase into inventory

### System

- `GET /health`: Check API health status

## Database Schema

The system uses the following main data models:

- **Product**: Base product information (name, SKU, price, etc.)
- **Category**: Product categories
- **Location**: Inventory storage locations (warehouses, stores)
- **InventoryItem**: Product stock at a specific location
- **InventoryTransaction**: Record of inventory movements
- **Supplier**: Supplier information
- **Purchase**: Purchase orders from suppliers

## Development

### Database Migrations

The project uses Alembic for database migrations:

```bash
# Generate a new migration
alembic revision -m "description"

# Run migrations
alembic upgrade head

# Rollback migration
alembic downgrade -1
```