Fix code linting issues

- Fix unused imports in API endpoints
- Add proper __all__ exports in model and schema modules
- Add proper TYPE_CHECKING imports in models to prevent circular imports
- Fix import order in migrations
- Fix long lines in migration scripts
- All ruff checks passing

README.md

@@ -1,3 +1,133 @@
-# FastAPI Application
+# Small Business Inventory Management System
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+## Overview
+This project is a comprehensive inventory management system designed for small businesses. It provides a robust REST API for managing products, categories, suppliers, and inventory transactions, along with analytics for business insights.
+
+## Features
+- **User Authentication**: Secure login and user management
+- **Product Management**: CRUD operations for products with SKU, pricing, and stock levels
+- **Category Management**: Organize products into categories
+- **Supplier Management**: Track and manage your suppliers
+- **Inventory Transactions**: Record purchases, sales, returns, and adjustments
+- **Inventory Analytics**: Get insights into your inventory performance
+- **Stock Alerts**: Identify low stock and out-of-stock products
+
+## Tech Stack
+- **Framework**: FastAPI
+- **Database**: SQLite
+- **ORM**: SQLAlchemy
+- **Authentication**: JWT (JSON Web Tokens)
+- **Migrations**: Alembic
+
+## API Endpoints
+
+### Authentication
+- `POST /api/v1/auth/login` - Login to get access token
+- `POST /api/v1/auth/test-token` - Verify access token
+
+### Users
+- `GET /api/v1/users/` - List all users (admin only)
+- `POST /api/v1/users/` - Create a new user (admin only)
+- `GET /api/v1/users/me` - Get current user info
+- `PUT /api/v1/users/me` - Update current user info
+- `GET /api/v1/users/{user_id}` - Get user by ID
+- `PUT /api/v1/users/{user_id}` - Update user (admin only)
+
+### Categories
+- `GET /api/v1/categories/` - List all categories
+- `POST /api/v1/categories/` - Create a new category
+- `GET /api/v1/categories/{id}` - Get category by ID
+- `PUT /api/v1/categories/{id}` - Update category
+- `DELETE /api/v1/categories/{id}` - Delete category (admin only)
+
+### Suppliers
+- `GET /api/v1/suppliers/` - List all suppliers
+- `POST /api/v1/suppliers/` - Create a new supplier
+- `GET /api/v1/suppliers/{id}` - Get supplier by ID
+- `PUT /api/v1/suppliers/{id}` - Update supplier
+- `DELETE /api/v1/suppliers/{id}` - Delete supplier (admin only)
+
+### Products
+- `GET /api/v1/products/` - List all products
+- `POST /api/v1/products/` - Create a new product
+- `GET /api/v1/products/{id}` - Get product by ID
+- `PUT /api/v1/products/{id}` - Update product
+- `DELETE /api/v1/products/{id}` - Delete product
+- `GET /api/v1/products/by-category/{category_id}` - Get products by category
+- `GET /api/v1/products/by-supplier/{supplier_id}` - Get products by supplier
+- `GET /api/v1/products/low-stock` - Get low stock products
+- `GET /api/v1/products/out-of-stock` - Get out of stock products
+
+### Inventory Transactions
+- `POST /api/v1/inventory-transactions/` - Create a new transaction
+- `GET /api/v1/inventory-transactions/` - List all transactions
+- `GET /api/v1/inventory-transactions/{id}` - Get transaction by ID
+- `GET /api/v1/inventory-transactions/by-product/{product_id}` - Get transactions by product
+- `GET /api/v1/inventory-transactions/by-type/{transaction_type}` - Get transactions by type
+
+### Analytics
+- `GET /api/v1/analytics/inventory-summary` - Get inventory summary
+- `GET /api/v1/analytics/transaction-history` - Get transaction history
+- `GET /api/v1/analytics/product-performance` - Get product performance
+- `GET /api/v1/analytics/category-performance` - Get category performance
+
+## Installation and Setup
+
+### Prerequisites
+- Python 3.8+
+- pip
+
+### Setting Up the Environment
+1. Clone the repository:
+   ```bash
+   git clone <repository-url>
+   cd smallbusinessinventorymanagementsystem
+   ```
+
+2. Install the required packages:
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+3. Create a `.env` file in the root directory (optional):
+   ```
+   SECRET_KEY=your_secret_key_here
+   ACCESS_TOKEN_EXPIRE_MINUTES=43200  # 30 days
+   ```
+
+### Database Setup
+1. The application uses SQLite by default, stored at `/app/storage/db/db.sqlite`.
+
+2. Run the database migrations:
+   ```bash
+   alembic upgrade head
+   ```
+
+### Running the Application
+1. Start the FastAPI server:
+   ```bash
+   uvicorn main:app --reload
+   ```
+
+2. Access the API documentation at:
+   - Swagger UI: http://localhost:8000/docs
+   - ReDoc: http://localhost:8000/redoc
+
+## Environment Variables
+| Variable | Description | Default |
+|----------|-------------|---------|
+| SECRET_KEY | Secret key for JWT encoding | "CHANGE_ME_IN_PRODUCTION" |
+| ACCESS_TOKEN_EXPIRE_MINUTES | Token expiration time in minutes | 10080 (7 days) |
+| SQLALCHEMY_DATABASE_URL | Database connection URL | "sqlite:///app/storage/db/db.sqlite" |
+
+## Development
+### Creating a Superuser
+To create a superuser account, you can use the API or add a user directly to the database with the `is_superuser` flag set to `True`.
+
+### Running Tests
+```bash
+pytest
+```
+
+## License
+This project is licensed under the MIT License - see the LICENSE file for details.

alembic.ini

@@ -0,0 +1,103 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.
+prepend_sys_path = .
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the python-dateutil library that can be
+# installed by adding `alembic[tz]` to the pip requirements
+# string value is passed to dateutil.tz.gettz()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the
+# "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to migrations/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "version_path_separator" below.
+# version_locations = %(here)s/bar:%(here)s/bat:migrations/versions
+
+# version path separator; As mentioned above, this is the character used to split
+# version_locations. The default within new alembic.ini files is "os", which uses os.pathsep.
+# If this key is omitted entirely, it falls back to the legacy behavior of splitting on spaces and/or commas.
+# Valid values for version_path_separator are:
+#
+# version_path_separator = :
+# version_path_separator = ;
+# version_path_separator = space
+version_path_separator = os  # Use os.pathsep. Default configuration used for new projects.
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# Specify the SQLite URL
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

app/api/deps.py

@@ -0,0 +1,62 @@
+
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from jose import jwt
+from pydantic import ValidationError
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.core import security
+from app.core.config import settings
+from app.db.session import get_db
+
+reusable_oauth2 = OAuth2PasswordBearer(
+    tokenUrl=f"{settings.API_V1_STR}/auth/login"
+)
+
+
+def get_current_user(
+    db: Session = Depends(get_db), token: str = Depends(reusable_oauth2)
+) -> models.User:
+    """
+    Dependency to get the current user from the token.
+    """
+    try:
+        payload = jwt.decode(
+            token, settings.SECRET_KEY, algorithms=[security.ALGORITHM]
+        )
+        token_data = schemas.TokenPayload(**payload)
+    except (jwt.JWTError, ValidationError):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Could not validate credentials",
+        )
+    user = crud.user.get(db, id=token_data.sub)
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+    return user
+
+
+def get_current_active_user(
+    current_user: models.User = Depends(get_current_user),
+) -> models.User:
+    """
+    Dependency to get the current active user.
+    """
+    if not current_user.is_active:
+        raise HTTPException(status_code=400, detail="Inactive user")
+    return current_user
+
+
+def get_current_active_superuser(
+    current_user: models.User = Depends(get_current_user),
+) -> models.User:
+    """
+    Dependency to get the current active superuser.
+    """
+    if not current_user.is_superuser:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="The user doesn't have enough privileges",
+        )
+    return current_user

app/api/v1/api.py

@@ -0,0 +1,40 @@
+from fastapi import APIRouter
+
+from app.api.v1.endpoints import (
+    analytics,
+    auth,
+    categories,
+    inventory_transactions,
+    products,
+    suppliers,
+    users,
+)
+
+api_router = APIRouter()
+
+# Auth routes
+api_router.include_router(auth.router, prefix="/auth", tags=["authentication"])
+
+# User routes
+api_router.include_router(users.router, prefix="/users", tags=["users"])
+
+# Category routes
+api_router.include_router(categories.router, prefix="/categories", tags=["categories"])
+
+# Supplier routes
+api_router.include_router(suppliers.router, prefix="/suppliers", tags=["suppliers"])
+
+# Product routes
+api_router.include_router(products.router, prefix="/products", tags=["products"])
+
+# Inventory transaction routes
+api_router.include_router(
+    inventory_transactions.router,
+    prefix="/inventory-transactions",
+    tags=["inventory-transactions"],
+)
+
+# Analytics routes
+api_router.include_router(
+    analytics.router, prefix="/analytics", tags=["analytics"]
+)

app/api/v1/endpoints/analytics.py

@@ -0,0 +1,250 @@
+from datetime import datetime, timedelta
+from typing import Any
+
+from fastapi import APIRouter, Depends
+from sqlalchemy import func
+from sqlalchemy.orm import Session
+
+from app import crud, models
+from app.api import deps
+from app.models.inventory_transaction import TransactionType
+
+router = APIRouter()
+
+
+@router.get("/inventory-summary")
+def get_inventory_summary(
+    db: Session = Depends(deps.get_db),
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get summary of inventory status.
+    """
+    # Get all products belonging to the user
+    products = crud.product.get_multi_by_owner(db, owner_id=current_user.id)
+    
+    # Calculate summary statistics
+    total_products = len(products)
+    total_inventory_value = sum(p.quantity * p.cost for p in products)
+    total_retail_value = sum(p.quantity * p.price for p in products)
+    potential_profit = total_retail_value - total_inventory_value
+    
+    low_stock_count = len([p for p in products if 0 < p.quantity <= p.reorder_level])
+    out_of_stock_count = len([p for p in products if p.quantity == 0])
+    in_stock_count = total_products - low_stock_count - out_of_stock_count
+    
+    return {
+        "total_products": total_products,
+        "total_inventory_value": round(total_inventory_value, 2),
+        "total_retail_value": round(total_retail_value, 2),
+        "potential_profit": round(potential_profit, 2),
+        "inventory_status": {
+            "in_stock": in_stock_count,
+            "low_stock": low_stock_count,
+            "out_of_stock": out_of_stock_count
+        }
+    }
+
+
+@router.get("/transaction-history")
+def get_transaction_history(
+    db: Session = Depends(deps.get_db),
+    days: int = 30,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get transaction history for the specified number of days.
+    """
+    # Get all products belonging to the user
+    products = crud.product.get_multi_by_owner(db, owner_id=current_user.id)
+    product_ids = [p.id for p in products]
+    
+    # Get date range
+    end_date = datetime.utcnow()
+    start_date = end_date - timedelta(days=days)
+    
+    # Get transactions for those products within the date range
+    transactions = (
+        db.query(
+            models.InventoryTransaction.transaction_type,
+            func.count().label("count"),
+            func.sum(models.InventoryTransaction.quantity).label("total_quantity"),
+        )
+        .filter(
+            models.InventoryTransaction.product_id.in_(product_ids),
+            models.InventoryTransaction.transaction_date >= start_date,
+            models.InventoryTransaction.transaction_date <= end_date,
+        )
+        .group_by(models.InventoryTransaction.transaction_type)
+        .all()
+    )
+    
+    # Format results
+    result = {}
+    for t_type in TransactionType:
+        result[t_type.value] = {"count": 0, "total_quantity": 0}
+    
+    for t_type, count, total_quantity in transactions:
+        result[t_type.value] = {
+            "count": count,
+            "total_quantity": total_quantity or 0
+        }
+    
+    return {
+        "period_days": days,
+        "start_date": start_date.isoformat(),
+        "end_date": end_date.isoformat(),
+        "transactions_by_type": result
+    }
+
+
+@router.get("/product-performance")
+def get_product_performance(
+    db: Session = Depends(deps.get_db),
+    days: int = 30,
+    limit: int = 10,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get top-selling products for the specified number of days.
+    """
+    # Get all products belonging to the user
+    products = crud.product.get_multi_by_owner(db, owner_id=current_user.id)
+    product_dict = {p.id: p for p in products}
+    
+    # Get date range
+    end_date = datetime.utcnow()
+    start_date = end_date - timedelta(days=days)
+    
+    # Get sales transactions grouped by product
+    sales = (
+        db.query(
+            models.InventoryTransaction.product_id,
+            func.sum(models.InventoryTransaction.quantity).label("quantity_sold"),
+        )
+        .filter(
+            models.InventoryTransaction.product_id.in_(product_dict.keys()),
+            models.InventoryTransaction.transaction_type == TransactionType.SALE,
+            models.InventoryTransaction.transaction_date >= start_date,
+            models.InventoryTransaction.transaction_date <= end_date,
+        )
+        .group_by(models.InventoryTransaction.product_id)
+        .order_by(func.sum(models.InventoryTransaction.quantity).desc())
+        .limit(limit)
+        .all()
+    )
+    
+    # Format results
+    top_selling = []
+    for product_id, quantity_sold in sales:
+        product = product_dict.get(product_id)
+        if product:
+            top_selling.append({
+                "id": product.id,
+                "name": product.name,
+                "sku": product.sku,
+                "quantity_sold": quantity_sold,
+                "revenue": round(quantity_sold * product.price, 2),
+                "profit": round(quantity_sold * (product.price - product.cost), 2),
+            })
+    
+    return {
+        "period_days": days,
+        "start_date": start_date.isoformat(),
+        "end_date": end_date.isoformat(),
+        "top_selling_products": top_selling
+    }
+
+
+@router.get("/category-performance")
+def get_category_performance(
+    db: Session = Depends(deps.get_db),
+    days: int = 30,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get sales performance by category for the specified number of days.
+    """
+    # Get all products belonging to the user
+    products = crud.product.get_multi_by_owner(db, owner_id=current_user.id)
+    
+    # Collect category IDs
+    category_ids = set()
+    for p in products:
+        if p.category_id:
+            category_ids.add(p.category_id)
+    
+    # Get categories
+    categories = crud.category.get_multi_by_ids(db, ids=list(category_ids))
+    category_dict = {c.id: c for c in categories}
+    
+    # Get date range
+    end_date = datetime.utcnow()
+    start_date = end_date - timedelta(days=days)
+    
+    # Get sales transactions for these products
+    sales = (
+        db.query(
+            models.Product.category_id,
+            func.sum(models.InventoryTransaction.quantity).label("quantity_sold"),
+        )
+        .join(
+            models.InventoryTransaction,
+            models.InventoryTransaction.product_id == models.Product.id
+        )
+        .filter(
+            models.Product.owner_id == current_user.id,
+            models.InventoryTransaction.transaction_type == TransactionType.SALE,
+            models.InventoryTransaction.transaction_date >= start_date,
+            models.InventoryTransaction.transaction_date <= end_date,
+        )
+        .group_by(models.Product.category_id)
+        .all()
+    )
+    
+    # Format results
+    category_performance = []
+    for category_id, quantity_sold in sales:
+        # Skip None category
+        if not category_id:
+            continue
+            
+        category = category_dict.get(category_id)
+        if category:
+            # Calculate revenue and profit for this category
+            revenue = 0
+            profit = 0
+            for p in products:
+                if p.category_id == category_id:
+                    # Get sales for this specific product
+                    product_sales = (
+                        db.query(func.sum(models.InventoryTransaction.quantity))
+                        .filter(
+                            models.InventoryTransaction.product_id == p.id,
+                            models.InventoryTransaction.transaction_type == TransactionType.SALE,
+                            models.InventoryTransaction.transaction_date >= start_date,
+                            models.InventoryTransaction.transaction_date <= end_date,
+                        )
+                        .scalar() or 0
+                    )
+                    
+                    revenue += product_sales * p.price
+                    profit += product_sales * (p.price - p.cost)
+            
+            category_performance.append({
+                "id": category.id,
+                "name": category.name,
+                "quantity_sold": quantity_sold,
+                "revenue": round(revenue, 2),
+                "profit": round(profit, 2),
+            })
+    
+    # Sort by revenue
+    category_performance.sort(key=lambda x: x["revenue"], reverse=True)
+    
+    return {
+        "period_days": days,
+        "start_date": start_date.isoformat(),
+        "end_date": end_date.isoformat(),
+        "category_performance": category_performance
+    }

app/api/v1/endpoints/auth.py

@@ -0,0 +1,49 @@
+from datetime import timedelta
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordRequestForm
+from sqlalchemy.orm import Session
+
+from app import crud, schemas
+from app.api import deps
+from app.core import security
+from app.core.config import settings
+
+router = APIRouter()
+
+
+@router.post("/login", response_model=schemas.Token)
+def login_access_token(
+    db: Session = Depends(deps.get_db), form_data: OAuth2PasswordRequestForm = Depends()
+) -> Any:
+    """
+    OAuth2 compatible token login, get an access token for future requests.
+    """
+    user = crud.user.authenticate(
+        db, email=form_data.username, password=form_data.password
+    )
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect email or password",
+        )
+    elif not crud.user.is_active(user):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST, detail="Inactive user"
+        )
+    access_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    return {
+        "access_token": security.create_access_token(
+            user.id, expires_delta=access_token_expires
+        ),
+        "token_type": "bearer",
+    }
+
+
+@router.post("/test-token", response_model=schemas.User)
+def test_token(current_user: schemas.User = Depends(deps.get_current_user)) -> Any:
+    """
+    Test access token.
+    """
+    return current_user

app/api/v1/endpoints/categories.py

@@ -0,0 +1,88 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.Category])
+def read_categories(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve categories.
+    """
+    categories = crud.category.get_multi(db, skip=skip, limit=limit)
+    return categories
+
+
+@router.post("/", response_model=schemas.Category)
+def create_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    category_in: schemas.CategoryCreate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Create new category.
+    """
+    category = crud.category.create(db, obj_in=category_in)
+    return category
+
+
+@router.get("/{id}", response_model=schemas.Category)
+def read_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get category by ID.
+    """
+    category = crud.category.get(db, id=id)
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    return category
+
+
+@router.put("/{id}", response_model=schemas.Category)
+def update_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    category_in: schemas.CategoryUpdate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Update a category.
+    """
+    category = crud.category.get(db, id=id)
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    category = crud.category.update(db, db_obj=category, obj_in=category_in)
+    return category
+
+
+@router.delete("/{id}", status_code=204, response_model=None)
+def delete_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Delete a category.
+    """
+    category = crud.category.get(db, id=id)
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    crud.category.remove(db, id=id)
+    return None

app/api/v1/endpoints/inventory_transactions.py

@@ -0,0 +1,135 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.api import deps
+from app.models.inventory_transaction import TransactionType
+
+router = APIRouter()
+
+
+@router.post("/", response_model=schemas.InventoryTransaction)
+def create_inventory_transaction(
+    *,
+    db: Session = Depends(deps.get_db),
+    transaction_in: schemas.InventoryTransactionCreate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Create new inventory transaction.
+    """
+    # Verify product exists and belongs to the current user
+    product = crud.product.get(db, id=transaction_in.product_id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    if product.owner_id != current_user.id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    
+    try:
+        transaction = crud.inventory_transaction.create_with_product_update(
+            db, obj_in=transaction_in
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    
+    return transaction
+
+
+@router.get("/", response_model=List[schemas.InventoryTransaction])
+def read_inventory_transactions(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve inventory transactions.
+    """
+    # Get all products belonging to the user
+    products = crud.product.get_multi_by_owner(db, owner_id=current_user.id)
+    product_ids = [p.id for p in products]
+    
+    # Get transactions for those products
+    transactions = db.query(models.InventoryTransaction).filter(
+        models.InventoryTransaction.product_id.in_(product_ids)
+    ).order_by(
+        models.InventoryTransaction.transaction_date.desc()
+    ).offset(skip).limit(limit).all()
+    
+    return transactions
+
+
+@router.get("/by-product/{product_id}", response_model=List[schemas.InventoryTransaction])
+def read_inventory_transactions_by_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    product_id: str,
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve inventory transactions by product.
+    """
+    # Verify product exists and belongs to the current user
+    product = crud.product.get(db, id=product_id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    if product.owner_id != current_user.id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    
+    transactions = crud.inventory_transaction.get_by_product(
+        db, product_id=product_id, skip=skip, limit=limit
+    )
+    return transactions
+
+
+@router.get("/by-type/{transaction_type}", response_model=List[schemas.InventoryTransaction])
+def read_inventory_transactions_by_type(
+    *,
+    db: Session = Depends(deps.get_db),
+    transaction_type: TransactionType,
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve inventory transactions by transaction type.
+    """
+    # Get all products belonging to the user
+    products = crud.product.get_multi_by_owner(db, owner_id=current_user.id)
+    product_ids = [p.id for p in products]
+    
+    # Get transactions for those products with the specified type
+    transactions = db.query(models.InventoryTransaction).filter(
+        models.InventoryTransaction.product_id.in_(product_ids),
+        models.InventoryTransaction.transaction_type == transaction_type
+    ).order_by(
+        models.InventoryTransaction.transaction_date.desc()
+    ).offset(skip).limit(limit).all()
+    
+    return transactions
+
+
+@router.get("/{id}", response_model=schemas.InventoryTransaction)
+def read_inventory_transaction(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get inventory transaction by ID.
+    """
+    transaction = crud.inventory_transaction.get(db, id=id)
+    if not transaction:
+        raise HTTPException(status_code=404, detail="Inventory transaction not found")
+    
+    # Verify product belongs to the current user
+    product = crud.product.get(db, id=transaction.product_id)
+    if product.owner_id != current_user.id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    
+    return transaction

app/api/v1/endpoints/products.py

@@ -0,0 +1,178 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.Product])
+def read_products(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve products.
+    """
+    products = crud.product.get_multi_by_owner(
+        db, owner_id=current_user.id, skip=skip, limit=limit
+    )
+    return products
+
+
+@router.post("/", response_model=schemas.Product)
+def create_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    product_in: schemas.ProductCreate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Create new product.
+    """
+    # Check if product with same SKU already exists
+    product = crud.product.get_by_sku(db, sku=product_in.sku)
+    if product:
+        raise HTTPException(
+            status_code=400,
+            detail="A product with this SKU already exists.",
+        )
+    
+    product = crud.product.create_with_owner(
+        db, obj_in=product_in, owner_id=current_user.id
+    )
+    return product
+
+
+@router.get("/{id}", response_model=schemas.Product)
+def read_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get product by ID.
+    """
+    product = crud.product.get(db, id=id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    if product.owner_id != current_user.id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    return product
+
+
+@router.put("/{id}", response_model=schemas.Product)
+def update_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    product_in: schemas.ProductUpdate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Update a product.
+    """
+    product = crud.product.get(db, id=id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    if product.owner_id != current_user.id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    product = crud.product.update(db, db_obj=product, obj_in=product_in)
+    return product
+
+
+@router.delete("/{id}", status_code=204, response_model=None)
+def delete_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Delete a product.
+    """
+    product = crud.product.get(db, id=id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    if product.owner_id != current_user.id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    crud.product.remove(db, id=id)
+    return None
+
+
+@router.get("/by-category/{category_id}", response_model=List[schemas.Product])
+def read_products_by_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    category_id: str,
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve products by category.
+    """
+    products = crud.product.get_multi_by_category(
+        db, category_id=category_id, skip=skip, limit=limit
+    )
+    # Filter by owner
+    return [p for p in products if p.owner_id == current_user.id]
+
+
+@router.get("/by-supplier/{supplier_id}", response_model=List[schemas.Product])
+def read_products_by_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    supplier_id: str,
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve products by supplier.
+    """
+    products = crud.product.get_multi_by_supplier(
+        db, supplier_id=supplier_id, skip=skip, limit=limit
+    )
+    # Filter by owner
+    return [p for p in products if p.owner_id == current_user.id]
+
+
+@router.get("/low-stock", response_model=List[schemas.Product])
+def read_low_stock_products(
+    *,
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve products with stock levels below reorder level.
+    """
+    products = crud.product.get_low_stock_products(
+        db, owner_id=current_user.id, skip=skip, limit=limit
+    )
+    return products
+
+
+@router.get("/out-of-stock", response_model=List[schemas.Product])
+def read_out_of_stock_products(
+    *,
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve products with zero stock.
+    """
+    products = crud.product.get_out_of_stock_products(
+        db, owner_id=current_user.id, skip=skip, limit=limit
+    )
+    return products

app/api/v1/endpoints/suppliers.py

@@ -0,0 +1,88 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.Supplier])
+def read_suppliers(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve suppliers.
+    """
+    suppliers = crud.supplier.get_multi(db, skip=skip, limit=limit)
+    return suppliers
+
+
+@router.post("/", response_model=schemas.Supplier)
+def create_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    supplier_in: schemas.SupplierCreate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Create new supplier.
+    """
+    supplier = crud.supplier.create(db, obj_in=supplier_in)
+    return supplier
+
+
+@router.get("/{id}", response_model=schemas.Supplier)
+def read_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get supplier by ID.
+    """
+    supplier = crud.supplier.get(db, id=id)
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    return supplier
+
+
+@router.put("/{id}", response_model=schemas.Supplier)
+def update_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    supplier_in: schemas.SupplierUpdate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Update a supplier.
+    """
+    supplier = crud.supplier.get(db, id=id)
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    supplier = crud.supplier.update(db, db_obj=supplier, obj_in=supplier_in)
+    return supplier
+
+
+@router.delete("/{id}", status_code=204, response_model=None)
+def delete_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: str,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Delete a supplier.
+    """
+    supplier = crud.supplier.get(db, id=id)
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    crud.supplier.remove(db, id=id)
+    return None

app/api/v1/endpoints/users.py

@@ -0,0 +1,120 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Body, Depends, HTTPException, status
+from fastapi.encoders import jsonable_encoder
+from pydantic import EmailStr
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.User])
+def read_users(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Retrieve users.
+    """
+    users = crud.user.get_multi(db, skip=skip, limit=limit)
+    return users
+
+
+@router.post("/", response_model=schemas.User)
+def create_user(
+    *,
+    db: Session = Depends(deps.get_db),
+    user_in: schemas.UserCreate,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Create new user.
+    """
+    user = crud.user.get_by_email(db, email=user_in.email)
+    if user:
+        raise HTTPException(
+            status_code=400,
+            detail="A user with this email already exists.",
+        )
+    user = crud.user.create(db, obj_in=user_in)
+    return user
+
+
+@router.put("/me", response_model=schemas.User)
+def update_user_me(
+    *,
+    db: Session = Depends(deps.get_db),
+    password: str = Body(None),
+    full_name: str = Body(None),
+    email: EmailStr = Body(None),
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Update own user.
+    """
+    current_user_data = jsonable_encoder(current_user)
+    user_in = schemas.UserUpdate(**current_user_data)
+    if password is not None:
+        user_in.password = password
+    if full_name is not None:
+        user_in.full_name = full_name
+    if email is not None:
+        user_in.email = email
+    user = crud.user.update(db, db_obj=current_user, obj_in=user_in)
+    return user
+
+
+@router.get("/me", response_model=schemas.User)
+def read_user_me(
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get current user.
+    """
+    return current_user
+
+
+@router.get("/{user_id}", response_model=schemas.User)
+def read_user_by_id(
+    user_id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+    db: Session = Depends(deps.get_db),
+) -> Any:
+    """
+    Get a specific user by id.
+    """
+    user = crud.user.get(db, id=user_id)
+    if user == current_user:
+        return user
+    if not crud.user.is_superuser(current_user):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="The user doesn't have enough privileges",
+        )
+    return user
+
+
+@router.put("/{user_id}", response_model=schemas.User)
+def update_user(
+    *,
+    db: Session = Depends(deps.get_db),
+    user_id: str,
+    user_in: schemas.UserUpdate,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Update a user.
+    """
+    user = crud.user.get(db, id=user_id)
+    if not user:
+        raise HTTPException(
+            status_code=404,
+            detail="The user with this ID does not exist in the system",
+        )
+    user = crud.user.update(db, db_obj=user, obj_in=user_in)
+    return user

app/core/config.py

@@ -0,0 +1,66 @@
+from pathlib import Path
+from typing import List
+
+from pydantic import AnyHttpUrl, EmailStr, validator
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    PROJECT_NAME: str = "Small Business Inventory Management System"
+    DESCRIPTION: str = "API for managing inventory for small businesses"
+    VERSION: str = "0.1.0"
+    API_V1_STR: str = "/api/v1"
+    
+    # SECURITY
+    SECRET_KEY: str = "CHANGE_ME_IN_PRODUCTION"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 60 * 24 * 7  # 7 days
+    
+    # Database setup
+    DB_DIR = Path("/app") / "storage" / "db"
+    DB_DIR.mkdir(parents=True, exist_ok=True)
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+
+    # CORS
+    BACKEND_CORS_ORIGINS: List[AnyHttpUrl] = []
+
+    @validator("BACKEND_CORS_ORIGINS", pre=True)
+    def assemble_cors_origins(cls, v: str | List[str]) -> List[str] | str:
+        if isinstance(v, str) and not v.startswith("["):
+            return [i.strip() for i in v.split(",")]
+        elif isinstance(v, (list, str)):
+            return v
+        raise ValueError(v)
+
+    # Email
+    SMTP_TLS: bool = True
+    SMTP_PORT: int | None = None
+    SMTP_HOST: str | None = None
+    SMTP_USER: str | None = None
+    SMTP_PASSWORD: str | None = None
+    EMAILS_FROM_EMAIL: EmailStr | None = None
+    EMAILS_FROM_NAME: str | None = None
+
+    @validator("EMAILS_FROM_NAME")
+    def get_project_name(cls, v: str | None, values: dict) -> str:
+        if not v:
+            return values["PROJECT_NAME"]
+        return v
+
+    EMAIL_RESET_TOKEN_EXPIRE_HOURS: int = 48
+    EMAIL_TEMPLATES_DIR: str = "/app/app/email-templates/build"
+    EMAILS_ENABLED: bool = False
+
+    @validator("EMAILS_ENABLED", pre=True)
+    def get_emails_enabled(cls, v: bool, values: dict) -> bool:
+        return bool(
+            values.get("SMTP_HOST")
+            and values.get("SMTP_PORT")
+            and values.get("EMAILS_FROM_EMAIL")
+        )
+
+    class Config:
+        case_sensitive = True
+        env_file = ".env"
+
+
+settings = Settings()

app/core/security.py

@@ -0,0 +1,42 @@
+from datetime import datetime, timedelta
+from typing import Any, Optional
+
+from jose import jwt
+from passlib.context import CryptContext
+
+from app.core.config import settings
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+ALGORITHM = "HS256"
+
+
+def create_access_token(
+    subject: str | Any, expires_delta: Optional[timedelta] = None
+) -> str:
+    """
+    Create a JWT token with the given subject and expiration time.
+    """
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(
+            minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
+        )
+    to_encode = {"exp": expire, "sub": str(subject)}
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=ALGORITHM)
+    return encoded_jwt
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """
+    Verify a password against a hash.
+    """
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    """
+    Hash a password.
+    """
+    return pwd_context.hash(password)

app/crud/__init__.py

@@ -0,0 +1,7 @@
+from app.crud.crud_category import category
+from app.crud.crud_inventory_transaction import inventory_transaction
+from app.crud.crud_product import product
+from app.crud.crud_supplier import supplier
+from app.crud.crud_user import user
+
+__all__ = ["category", "inventory_transaction", "product", "supplier", "user"]

app/crud/base.py

@@ -0,0 +1,84 @@
+from typing import Any, Dict, Generic, List, Optional, Type, TypeVar, Union
+
+from fastapi.encoders import jsonable_encoder
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+
+from app.db.base_class import Base
+
+ModelType = TypeVar("ModelType", bound=Base)
+CreateSchemaType = TypeVar("CreateSchemaType", bound=BaseModel)
+UpdateSchemaType = TypeVar("UpdateSchemaType", bound=BaseModel)
+
+
+class CRUDBase(Generic[ModelType, CreateSchemaType, UpdateSchemaType]):
+    """
+    Base class for CRUD operations.
+    """
+    def __init__(self, model: Type[ModelType]):
+        """
+        CRUD object with default methods to Create, Read, Update, Delete (CRUD).
+        
+        **Parameters**
+        
+        * `model`: A SQLAlchemy model class
+        * `schema`: A Pydantic model (schema) class
+        """
+        self.model = model
+
+    def get(self, db: Session, id: Any) -> Optional[ModelType]:
+        """
+        Get a record by ID.
+        """
+        return db.query(self.model).filter(self.model.id == id).first()
+
+    def get_multi(
+        self, db: Session, *, skip: int = 0, limit: int = 100
+    ) -> List[ModelType]:
+        """
+        Get multiple records.
+        """
+        return db.query(self.model).offset(skip).limit(limit).all()
+
+    def create(self, db: Session, *, obj_in: CreateSchemaType) -> ModelType:
+        """
+        Create a new record.
+        """
+        obj_in_data = jsonable_encoder(obj_in)
+        db_obj = self.model(**obj_in_data)  # type: ignore
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def update(
+        self,
+        db: Session,
+        *,
+        db_obj: ModelType,
+        obj_in: Union[UpdateSchemaType, Dict[str, Any]]
+    ) -> ModelType:
+        """
+        Update a record.
+        """
+        obj_data = jsonable_encoder(db_obj)
+        if isinstance(obj_in, dict):
+            update_data = obj_in
+        else:
+            update_data = obj_in.dict(exclude_unset=True)
+        for field in obj_data:
+            if field in update_data:
+                setattr(db_obj, field, update_data[field])
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def remove(self, db: Session, *, id: Any) -> ModelType:
+        """
+        Delete a record.
+        """
+        obj = db.query(self.model).get(id)
+        db.delete(obj)
+        db.commit()
+        return obj

app/crud/crud_category.py

@@ -0,0 +1,44 @@
+import uuid
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.category import Category
+from app.schemas.category import CategoryCreate, CategoryUpdate
+
+
+class CRUDCategory(CRUDBase[Category, CategoryCreate, CategoryUpdate]):
+    """
+    CRUD operations for Category model.
+    """
+    def get_by_name(self, db: Session, *, name: str) -> Optional[Category]:
+        """
+        Get a category by name.
+        """
+        return db.query(Category).filter(Category.name == name).first()
+
+    def create(self, db: Session, *, obj_in: CategoryCreate) -> Category:
+        """
+        Create a new category.
+        """
+        db_obj = Category(
+            id=str(uuid.uuid4()),
+            name=obj_in.name,
+            description=obj_in.description,
+        )
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def get_multi_by_ids(
+        self, db: Session, *, ids: List[str], skip: int = 0, limit: int = 100
+    ) -> List[Category]:
+        """
+        Get multiple categories by IDs.
+        """
+        return db.query(Category).filter(Category.id.in_(ids)).offset(skip).limit(limit).all()
+
+
+category = CRUDCategory(Category)

app/crud/crud_inventory_transaction.py

@@ -0,0 +1,105 @@
+import uuid
+from datetime import datetime
+from typing import List
+
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.inventory_transaction import InventoryTransaction, TransactionType
+from app.models.product import Product
+from app.schemas.inventory_transaction import (
+    InventoryTransactionCreate,
+    InventoryTransactionUpdate,
+)
+
+
+class CRUDInventoryTransaction(
+    CRUDBase[InventoryTransaction, InventoryTransactionCreate, InventoryTransactionUpdate]
+):
+    """
+    CRUD operations for InventoryTransaction model.
+    """
+    def create_with_product_update(
+        self, db: Session, *, obj_in: InventoryTransactionCreate
+    ) -> InventoryTransaction:
+        """
+        Create a new inventory transaction and update product quantity.
+        """
+        # Get the product
+        product = db.query(Product).filter(Product.id == obj_in.product_id).first()
+        if not product:
+            raise ValueError("Product not found")
+
+        # Calculate the quantity change based on transaction type
+        if obj_in.transaction_type == TransactionType.PURCHASE:
+            product.quantity += obj_in.quantity
+        elif obj_in.transaction_type == TransactionType.SALE:
+            if product.quantity < obj_in.quantity:
+                raise ValueError("Not enough inventory for sale")
+            product.quantity -= obj_in.quantity
+        elif obj_in.transaction_type == TransactionType.ADJUSTMENT:
+            product.quantity += obj_in.quantity  # Can be negative for reduction
+        elif obj_in.transaction_type == TransactionType.RETURN:
+            product.quantity += obj_in.quantity
+        elif obj_in.transaction_type == TransactionType.TRANSFER:
+            if product.quantity < obj_in.quantity:
+                raise ValueError("Not enough inventory for transfer")
+            product.quantity -= obj_in.quantity
+
+        # Create the transaction
+        db_obj = InventoryTransaction(
+            id=str(uuid.uuid4()),
+            transaction_type=obj_in.transaction_type,
+            quantity=obj_in.quantity,
+            transaction_date=obj_in.transaction_date or datetime.utcnow(),
+            notes=obj_in.notes,
+            unit_price=obj_in.unit_price,
+            reference_number=obj_in.reference_number,
+            product_id=obj_in.product_id,
+        )
+        
+        # Update the database
+        db.add(db_obj)
+        db.add(product)
+        db.commit()
+        db.refresh(db_obj)
+        
+        return db_obj
+
+    def get_by_product(
+        self, db: Session, *, product_id: str, skip: int = 0, limit: int = 100
+    ) -> List[InventoryTransaction]:
+        """
+        Get transactions by product ID.
+        """
+        return (
+            db.query(InventoryTransaction)
+            .filter(InventoryTransaction.product_id == product_id)
+            .order_by(InventoryTransaction.transaction_date.desc())
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+    def get_by_transaction_type(
+        self,
+        db: Session,
+        *,
+        transaction_type: TransactionType,
+        skip: int = 0,
+        limit: int = 100
+    ) -> List[InventoryTransaction]:
+        """
+        Get transactions by transaction type.
+        """
+        return (
+            db.query(InventoryTransaction)
+            .filter(InventoryTransaction.transaction_type == transaction_type)
+            .order_by(InventoryTransaction.transaction_date.desc())
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+
+inventory_transaction = CRUDInventoryTransaction(InventoryTransaction)

app/crud/crud_product.py

@@ -0,0 +1,118 @@
+import uuid
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.product import Product
+from app.schemas.product import ProductCreate, ProductUpdate
+
+
+class CRUDProduct(CRUDBase[Product, ProductCreate, ProductUpdate]):
+    """
+    CRUD operations for Product model.
+    """
+    def get_by_sku(self, db: Session, *, sku: str) -> Optional[Product]:
+        """
+        Get a product by SKU.
+        """
+        return db.query(Product).filter(Product.sku == sku).first()
+
+    def create_with_owner(
+        self, db: Session, *, obj_in: ProductCreate, owner_id: str
+    ) -> Product:
+        """
+        Create a new product with owner ID.
+        """
+        db_obj = Product(
+            id=str(uuid.uuid4()),
+            name=obj_in.name,
+            description=obj_in.description,
+            sku=obj_in.sku,
+            price=obj_in.price,
+            cost=obj_in.cost,
+            quantity=obj_in.quantity,
+            reorder_level=obj_in.reorder_level,
+            category_id=obj_in.category_id,
+            supplier_id=obj_in.supplier_id,
+            owner_id=owner_id,
+        )
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def get_multi_by_owner(
+        self, db: Session, *, owner_id: str, skip: int = 0, limit: int = 100
+    ) -> List[Product]:
+        """
+        Get multiple products by owner ID.
+        """
+        return (
+            db.query(Product)
+            .filter(Product.owner_id == owner_id)
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+    def get_multi_by_category(
+        self, db: Session, *, category_id: str, skip: int = 0, limit: int = 100
+    ) -> List[Product]:
+        """
+        Get multiple products by category ID.
+        """
+        return (
+            db.query(Product)
+            .filter(Product.category_id == category_id)
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+    def get_multi_by_supplier(
+        self, db: Session, *, supplier_id: str, skip: int = 0, limit: int = 100
+    ) -> List[Product]:
+        """
+        Get multiple products by supplier ID.
+        """
+        return (
+            db.query(Product)
+            .filter(Product.supplier_id == supplier_id)
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+    def get_low_stock_products(
+        self, db: Session, *, owner_id: str, skip: int = 0, limit: int = 100
+    ) -> List[Product]:
+        """
+        Get products with stock levels below reorder level.
+        """
+        return (
+            db.query(Product)
+            .filter(Product.owner_id == owner_id)
+            .filter(Product.quantity <= Product.reorder_level)
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+    def get_out_of_stock_products(
+        self, db: Session, *, owner_id: str, skip: int = 0, limit: int = 100
+    ) -> List[Product]:
+        """
+        Get products with zero stock.
+        """
+        return (
+            db.query(Product)
+            .filter(Product.owner_id == owner_id)
+            .filter(Product.quantity == 0)
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+
+product = CRUDProduct(Product)

app/crud/crud_supplier.py

@@ -0,0 +1,48 @@
+import uuid
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.supplier import Supplier
+from app.schemas.supplier import SupplierCreate, SupplierUpdate
+
+
+class CRUDSupplier(CRUDBase[Supplier, SupplierCreate, SupplierUpdate]):
+    """
+    CRUD operations for Supplier model.
+    """
+    def get_by_name(self, db: Session, *, name: str) -> Optional[Supplier]:
+        """
+        Get a supplier by name.
+        """
+        return db.query(Supplier).filter(Supplier.name == name).first()
+
+    def create(self, db: Session, *, obj_in: SupplierCreate) -> Supplier:
+        """
+        Create a new supplier.
+        """
+        db_obj = Supplier(
+            id=str(uuid.uuid4()),
+            name=obj_in.name,
+            contact_name=obj_in.contact_name,
+            email=obj_in.email,
+            phone=obj_in.phone,
+            address=obj_in.address,
+            notes=obj_in.notes,
+        )
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def get_multi_by_ids(
+        self, db: Session, *, ids: List[str], skip: int = 0, limit: int = 100
+    ) -> List[Supplier]:
+        """
+        Get multiple suppliers by IDs.
+        """
+        return db.query(Supplier).filter(Supplier.id.in_(ids)).offset(skip).limit(limit).all()
+
+
+supplier = CRUDSupplier(Supplier)

app/crud/crud_user.py

@@ -0,0 +1,78 @@
+import uuid
+from typing import Any, Dict, Optional, Union
+
+from sqlalchemy.orm import Session
+
+from app.core.security import get_password_hash, verify_password
+from app.crud.base import CRUDBase
+from app.models.user import User
+from app.schemas.user import UserCreate, UserUpdate
+
+
+class CRUDUser(CRUDBase[User, UserCreate, UserUpdate]):
+    """
+    CRUD operations for User model.
+    """
+    def get_by_email(self, db: Session, *, email: str) -> Optional[User]:
+        """
+        Get a user by email.
+        """
+        return db.query(User).filter(User.email == email).first()
+
+    def create(self, db: Session, *, obj_in: UserCreate) -> User:
+        """
+        Create a new user.
+        """
+        db_obj = User(
+            id=str(uuid.uuid4()),
+            email=obj_in.email,
+            hashed_password=get_password_hash(obj_in.password),
+            full_name=obj_in.full_name,
+            is_superuser=obj_in.is_superuser,
+        )
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def update(
+        self, db: Session, *, db_obj: User, obj_in: Union[UserUpdate, Dict[str, Any]]
+    ) -> User:
+        """
+        Update a user.
+        """
+        if isinstance(obj_in, dict):
+            update_data = obj_in
+        else:
+            update_data = obj_in.dict(exclude_unset=True)
+        if update_data.get("password"):
+            hashed_password = get_password_hash(update_data["password"])
+            del update_data["password"]
+            update_data["hashed_password"] = hashed_password
+        return super().update(db, db_obj=db_obj, obj_in=update_data)
+
+    def authenticate(self, db: Session, *, email: str, password: str) -> Optional[User]:
+        """
+        Authenticate a user.
+        """
+        user = self.get_by_email(db, email=email)
+        if not user:
+            return None
+        if not verify_password(password, user.hashed_password):
+            return None
+        return user
+
+    def is_active(self, user: User) -> bool:
+        """
+        Check if a user is active.
+        """
+        return user.is_active
+
+    def is_superuser(self, user: User) -> bool:
+        """
+        Check if a user is a superuser.
+        """
+        return user.is_superuser
+
+
+user = CRUDUser(User)

app/db/base.py

@@ -0,0 +1,8 @@
+# Import all the models, so that Base has them before being
+# imported by Alembic
+from app.db.base_class import Base  # noqa
+from app.models.user import User  # noqa
+from app.models.category import Category  # noqa
+from app.models.supplier import Supplier  # noqa
+from app.models.product import Product  # noqa
+from app.models.inventory_transaction import InventoryTransaction  # noqa

app/db/base_class.py

@@ -0,0 +1,19 @@
+from typing import Any
+
+from sqlalchemy.ext.declarative import declared_attr
+from sqlalchemy.orm import DeclarativeBase
+
+
+class Base(DeclarativeBase):
+    """
+    Base class for all database models.
+    """
+    
+    id: Any
+    
+    @declared_attr
+    def __tablename__(cls) -> str:
+        """
+        Generate __tablename__ automatically from the class name.
+        """
+        return cls.__name__.lower()

app/db/session.py

@@ -0,0 +1,20 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+engine = create_engine(
+    settings.SQLALCHEMY_DATABASE_URL, 
+    connect_args={"check_same_thread": False}
+)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+def get_db():
+    """
+    Dependency function to get a database session.
+    """
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1,7 @@
+from app.models.category import Category
+from app.models.inventory_transaction import InventoryTransaction, TransactionType
+from app.models.product import Product
+from app.models.supplier import Supplier
+from app.models.user import User
+
+__all__ = ["Category", "InventoryTransaction", "TransactionType", "Product", "Supplier", "User"]

app/models/category.py

@@ -0,0 +1,24 @@
+from datetime import datetime
+from typing import TYPE_CHECKING, List
+
+from sqlalchemy import Column, DateTime, String
+from sqlalchemy.orm import Mapped, relationship
+
+from app.db.base_class import Base
+
+if TYPE_CHECKING:
+    from app.models.product import Product
+
+
+class Category(Base):
+    """
+    Database model for product categories.
+    """
+    id = Column(String, primary_key=True, index=True)
+    name = Column(String, index=True, nullable=False)
+    description = Column(String, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    
+    # Relationships
+    products: Mapped[List["Product"]] = relationship("Product", back_populates="category")

app/models/inventory_transaction.py

@@ -0,0 +1,42 @@
+from datetime import datetime
+from enum import Enum as PyEnum
+from typing import TYPE_CHECKING
+
+from sqlalchemy import Column, DateTime, Enum, Float, ForeignKey, Integer, String
+from sqlalchemy.orm import Mapped, relationship
+
+from app.db.base_class import Base
+
+if TYPE_CHECKING:
+    from app.models.product import Product
+
+
+class TransactionType(str, PyEnum):
+    """
+    Enum for inventory transaction types.
+    """
+    PURCHASE = "purchase"
+    SALE = "sale"
+    ADJUSTMENT = "adjustment"
+    RETURN = "return"
+    TRANSFER = "transfer"
+
+
+class InventoryTransaction(Base):
+    """
+    Database model for inventory transactions.
+    """
+    id = Column(String, primary_key=True, index=True)
+    transaction_type = Column(Enum(TransactionType), nullable=False)
+    quantity = Column(Integer, nullable=False)
+    transaction_date = Column(DateTime, default=datetime.utcnow)
+    notes = Column(String, nullable=True)
+    unit_price = Column(Float, nullable=True)
+    reference_number = Column(String, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    
+    # Foreign keys
+    product_id = Column(String, ForeignKey("product.id"), nullable=False)
+    
+    # Relationships
+    product: Mapped["Product"] = relationship("Product", back_populates="inventory_transactions")

app/models/product.py

@@ -0,0 +1,42 @@
+from datetime import datetime
+from typing import TYPE_CHECKING, List, Optional
+
+from sqlalchemy import Column, DateTime, Float, ForeignKey, Integer, String
+from sqlalchemy.orm import Mapped, relationship
+
+from app.db.base_class import Base
+
+if TYPE_CHECKING:
+    from app.models.category import Category
+    from app.models.inventory_transaction import InventoryTransaction
+    from app.models.supplier import Supplier
+    from app.models.user import User
+
+
+class Product(Base):
+    """
+    Database model for products.
+    """
+    id = Column(String, primary_key=True, index=True)
+    name = Column(String, index=True, nullable=False)
+    description = Column(String, nullable=True)
+    sku = Column(String, unique=True, index=True, nullable=False)
+    price = Column(Float, nullable=False)
+    cost = Column(Float, nullable=False)
+    quantity = Column(Integer, default=0)
+    reorder_level = Column(Integer, default=10)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    
+    # Foreign keys
+    category_id = Column(String, ForeignKey("category.id"), nullable=True)
+    supplier_id = Column(String, ForeignKey("supplier.id"), nullable=True)
+    owner_id = Column(String, ForeignKey("user.id"), nullable=False)
+    
+    # Relationships
+    category: Mapped[Optional["Category"]] = relationship("Category", back_populates="products")
+    supplier: Mapped[Optional["Supplier"]] = relationship("Supplier", back_populates="products")
+    owner: Mapped["User"] = relationship("User", back_populates="products")
+    inventory_transactions: Mapped[List["InventoryTransaction"]] = relationship(
+        "InventoryTransaction", back_populates="product"
+    )

app/models/supplier.py

@@ -0,0 +1,28 @@
+from datetime import datetime
+from typing import TYPE_CHECKING, List
+
+from sqlalchemy import Column, DateTime, String
+from sqlalchemy.orm import Mapped, relationship
+
+from app.db.base_class import Base
+
+if TYPE_CHECKING:
+    from app.models.product import Product
+
+
+class Supplier(Base):
+    """
+    Database model for suppliers.
+    """
+    id = Column(String, primary_key=True, index=True)
+    name = Column(String, index=True, nullable=False)
+    contact_name = Column(String, nullable=True)
+    email = Column(String, nullable=True)
+    phone = Column(String, nullable=True)
+    address = Column(String, nullable=True)
+    notes = Column(String, nullable=True)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    
+    # Relationships
+    products: Mapped[List["Product"]] = relationship("Product", back_populates="supplier")

app/models/user.py

@@ -0,0 +1,27 @@
+from datetime import datetime
+from typing import TYPE_CHECKING, List
+
+from sqlalchemy import Boolean, Column, DateTime, String
+from sqlalchemy.orm import Mapped, relationship
+
+from app.db.base_class import Base
+
+if TYPE_CHECKING:
+    from app.models.product import Product
+
+
+class User(Base):
+    """
+    Database model for users.
+    """
+    id = Column(String, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True, nullable=False)
+    full_name = Column(String, nullable=True)
+    hashed_password = Column(String, nullable=False)
+    is_active = Column(Boolean, default=True)
+    is_superuser = Column(Boolean, default=False)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+    
+    # Relationships
+    products: Mapped[List["Product"]] = relationship("Product", back_populates="owner")

app/schemas/__init__.py

@@ -0,0 +1,19 @@
+from app.schemas.category import Category, CategoryCreate, CategoryUpdate
+from app.schemas.inventory_transaction import (
+    InventoryTransaction,
+    InventoryTransactionCreate,
+    InventoryTransactionUpdate,
+)
+from app.schemas.product import Product, ProductCreate, ProductUpdate
+from app.schemas.supplier import Supplier, SupplierCreate, SupplierUpdate
+from app.schemas.token import Token, TokenPayload
+from app.schemas.user import User, UserCreate, UserUpdate
+
+__all__ = [
+    "Category", "CategoryCreate", "CategoryUpdate",
+    "InventoryTransaction", "InventoryTransactionCreate", "InventoryTransactionUpdate",
+    "Product", "ProductCreate", "ProductUpdate",
+    "Supplier", "SupplierCreate", "SupplierUpdate",
+    "Token", "TokenPayload",
+    "User", "UserCreate", "UserUpdate",
+]

app/schemas/category.py

@@ -0,0 +1,49 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+# Shared properties
+class CategoryBase(BaseModel):
+    """
+    Base schema for category data.
+    """
+    name: Optional[str] = None
+    description: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class CategoryCreate(CategoryBase):
+    """
+    Schema for creating new categories.
+    """
+    name: str
+
+
+# Properties to receive via API on update
+class CategoryUpdate(CategoryBase):
+    """
+    Schema for updating category data.
+    """
+    pass
+
+
+class CategoryInDBBase(CategoryBase):
+    """
+    Base schema for category data from the database.
+    """
+    id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class Category(CategoryInDBBase):
+    """
+    Schema for category data to return via API.
+    """
+    pass

app/schemas/inventory_transaction.py

@@ -0,0 +1,58 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+from app.models.inventory_transaction import TransactionType
+
+
+# Shared properties
+class InventoryTransactionBase(BaseModel):
+    """
+    Base schema for inventory transaction data.
+    """
+    transaction_type: Optional[TransactionType] = None
+    quantity: Optional[int] = None
+    transaction_date: Optional[datetime] = None
+    notes: Optional[str] = None
+    unit_price: Optional[float] = None
+    reference_number: Optional[str] = None
+    product_id: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class InventoryTransactionCreate(InventoryTransactionBase):
+    """
+    Schema for creating new inventory transactions.
+    """
+    transaction_type: TransactionType
+    quantity: int
+    product_id: str
+    transaction_date: datetime = Field(default_factory=datetime.utcnow)
+
+
+# Properties to receive via API on update
+class InventoryTransactionUpdate(InventoryTransactionBase):
+    """
+    Schema for updating inventory transaction data.
+    """
+    pass
+
+
+class InventoryTransactionInDBBase(InventoryTransactionBase):
+    """
+    Base schema for inventory transaction data from the database.
+    """
+    id: str
+    created_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class InventoryTransaction(InventoryTransactionInDBBase):
+    """
+    Schema for inventory transaction data to return via API.
+    """
+    pass

app/schemas/product.py

@@ -0,0 +1,78 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+# Shared properties
+class ProductBase(BaseModel):
+    """
+    Base schema for product data.
+    """
+    name: Optional[str] = None
+    description: Optional[str] = None
+    sku: Optional[str] = None
+    price: Optional[float] = None
+    cost: Optional[float] = None
+    quantity: Optional[int] = None
+    reorder_level: Optional[int] = None
+    category_id: Optional[str] = None
+    supplier_id: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class ProductCreate(ProductBase):
+    """
+    Schema for creating new products.
+    """
+    name: str
+    sku: str
+    price: float
+    cost: float
+    quantity: int = 0
+    reorder_level: int = 10
+
+
+# Properties to receive via API on update
+class ProductUpdate(ProductBase):
+    """
+    Schema for updating product data.
+    """
+    pass
+
+
+class ProductInDBBase(ProductBase):
+    """
+    Base schema for product data from the database.
+    """
+    id: str
+    owner_id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class Product(ProductInDBBase):
+    """
+    Schema for product data to return via API.
+    """
+    pass
+
+
+# Additional properties for inventory status
+class ProductInventoryStatus(BaseModel):
+    """
+    Schema for product inventory status.
+    """
+    id: str
+    name: str
+    sku: str
+    quantity: int
+    reorder_level: int
+    status: str  # "In Stock", "Low Stock", "Out of Stock"
+
+    class Config:
+        from_attributes = True

app/schemas/supplier.py

@@ -0,0 +1,53 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, EmailStr
+
+
+# Shared properties
+class SupplierBase(BaseModel):
+    """
+    Base schema for supplier data.
+    """
+    name: Optional[str] = None
+    contact_name: Optional[str] = None
+    email: Optional[EmailStr] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+    notes: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class SupplierCreate(SupplierBase):
+    """
+    Schema for creating new suppliers.
+    """
+    name: str
+
+
+# Properties to receive via API on update
+class SupplierUpdate(SupplierBase):
+    """
+    Schema for updating supplier data.
+    """
+    pass
+
+
+class SupplierInDBBase(SupplierBase):
+    """
+    Base schema for supplier data from the database.
+    """
+    id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class Supplier(SupplierInDBBase):
+    """
+    Schema for supplier data to return via API.
+    """
+    pass

app/schemas/token.py

@@ -0,0 +1,18 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class Token(BaseModel):
+    """
+    Schema for authentication token response.
+    """
+    access_token: str
+    token_type: str
+
+
+class TokenPayload(BaseModel):
+    """
+    Schema for JWT token payload.
+    """
+    sub: Optional[str] = None

app/schemas/user.py

@@ -0,0 +1,60 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, EmailStr
+
+
+# Shared properties
+class UserBase(BaseModel):
+    """
+    Base schema for user data.
+    """
+    email: Optional[EmailStr] = None
+    full_name: Optional[str] = None
+    is_active: Optional[bool] = True
+    is_superuser: bool = False
+
+
+# Properties to receive via API on creation
+class UserCreate(UserBase):
+    """
+    Schema for creating new users.
+    """
+    email: EmailStr
+    password: str
+
+
+# Properties to receive via API on update
+class UserUpdate(UserBase):
+    """
+    Schema for updating user data.
+    """
+    password: Optional[str] = None
+
+
+class UserInDBBase(UserBase):
+    """
+    Base schema for user data from the database.
+    """
+    id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class User(UserInDBBase):
+    """
+    Schema for user data to return via API.
+    """
+    pass
+
+
+# Additional properties stored in DB
+class UserInDB(UserInDBBase):
+    """
+    Schema for user data stored in the database.
+    """
+    hashed_password: str

main.py

@@ -0,0 +1,49 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.v1.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    openapi_url="/openapi.json",
+    version=settings.VERSION,
+    description=settings.DESCRIPTION,
+)
+
+# Set up CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include API router
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+
+@app.get("/")
+async def root():
+    """
+    Root endpoint that returns basic application information.
+    """
+    return {
+        "title": settings.PROJECT_NAME,
+        "description": settings.DESCRIPTION,
+        "version": settings.VERSION,
+        "docs_url": "/docs",
+        "health_check": "/health",
+    }
+
+
+@app.get("/health", status_code=200)
+async def health_check():
+    """
+    Health check endpoint to verify the service is up and running.
+    """
+    return {
+        "status": "healthy",
+        "version": settings.VERSION,
+    }

migrations/env.py

@@ -0,0 +1,80 @@
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+from app.core.config import settings
+from app.db.base import Base  # noqa - imported for alembic autogenerate
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = settings.SQLALCHEMY_DATABASE_URL
+    context.configure(
+        url=url,
+        target_metadata=Base.metadata,
+        literal_binds=True,
+        compare_type=True,
+        render_as_batch=True,
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    configuration = config.get_section(config.config_ini_section)
+    configuration["sqlalchemy.url"] = settings.SQLALCHEMY_DATABASE_URL
+    connectable = engine_from_config(
+        configuration,
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        is_sqlite = connection.dialect.name == "sqlite"
+        context.configure(
+            connection=connection,
+            target_metadata=Base.metadata,
+            compare_type=True,
+            render_as_batch=is_sqlite,
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

migrations/script.py.mako

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/aaa1bc2a6d3c_initial_migration.py

@@ -0,0 +1,114 @@
+"""Initial migration
+
+Revision ID: aaa1bc2a6d3c
+Revises: 
+Create Date: 2023-11-16 12:00:00.000000
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = 'aaa1bc2a6d3c'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Create user table
+    op.create_table(
+        'user',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('email', sa.String(), nullable=False, unique=True, index=True),
+        sa.Column('full_name', sa.String(), nullable=True),
+        sa.Column('hashed_password', sa.String(), nullable=False),
+        sa.Column('is_active', sa.Boolean(), default=True),
+        sa.Column('is_superuser', sa.Boolean(), default=False),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column(
+            'updated_at',
+            sa.DateTime(),
+            default=sa.func.current_timestamp(),
+            onupdate=sa.func.current_timestamp()
+        ),
+    )
+    
+    # Create category table
+    op.create_table(
+        'category',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('name', sa.String(), nullable=False, index=True),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column(
+            'updated_at',
+            sa.DateTime(),
+            default=sa.func.current_timestamp(),
+            onupdate=sa.func.current_timestamp()
+        ),
+    )
+    
+    # Create supplier table
+    op.create_table(
+        'supplier',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('name', sa.String(), nullable=False, index=True),
+        sa.Column('contact_name', sa.String(), nullable=True),
+        sa.Column('email', sa.String(), nullable=True),
+        sa.Column('phone', sa.String(), nullable=True),
+        sa.Column('address', sa.String(), nullable=True),
+        sa.Column('notes', sa.String(), nullable=True),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column(
+            'updated_at',
+            sa.DateTime(),
+            default=sa.func.current_timestamp(),
+            onupdate=sa.func.current_timestamp()
+        ),
+    )
+    
+    # Create product table
+    op.create_table(
+        'product',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('name', sa.String(), nullable=False, index=True),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('sku', sa.String(), nullable=False, unique=True, index=True),
+        sa.Column('price', sa.Float(), nullable=False),
+        sa.Column('cost', sa.Float(), nullable=False),
+        sa.Column('quantity', sa.Integer(), default=0),
+        sa.Column('reorder_level', sa.Integer(), default=10),
+        sa.Column('category_id', sa.String(), sa.ForeignKey('category.id'), nullable=True),
+        sa.Column('supplier_id', sa.String(), sa.ForeignKey('supplier.id'), nullable=True),
+        sa.Column('owner_id', sa.String(), sa.ForeignKey('user.id'), nullable=False),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column(
+            'updated_at',
+            sa.DateTime(),
+            default=sa.func.current_timestamp(),
+            onupdate=sa.func.current_timestamp()
+        ),
+    )
+    
+    # Create inventory_transaction table
+    op.create_table(
+        'inventorytransaction',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('transaction_type', sa.String(), nullable=False),
+        sa.Column('quantity', sa.Integer(), nullable=False),
+        sa.Column('transaction_date', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column('notes', sa.String(), nullable=True),
+        sa.Column('unit_price', sa.Float(), nullable=True),
+        sa.Column('reference_number', sa.String(), nullable=True),
+        sa.Column('product_id', sa.String(), sa.ForeignKey('product.id'), nullable=False),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+    )
+
+
+def downgrade():
+    op.drop_table('inventorytransaction')
+    op.drop_table('product')
+    op.drop_table('supplier')
+    op.drop_table('category')
+    op.drop_table('user')

pyproject.toml

@@ -0,0 +1,13 @@
+[tool.ruff]
+line-length = 100
+target-version = "py38"
+
+[tool.ruff.lint]
+select = [
+    "E",  # pycodestyle errors
+    "F",  # pyflakes
+    "I",  # isort
+]
+
+[tool.ruff.lint.isort]
+known-third-party = ["fastapi", "pydantic", "starlette", "sqlalchemy"]

requirements.txt

@@ -0,0 +1,13 @@
+fastapi>=0.103.1
+uvicorn>=0.23.2
+sqlalchemy>=2.0.20
+pydantic>=2.4.2
+pydantic-settings>=2.0.3
+alembic>=1.12.0
+python-jose>=3.3.0
+passlib>=1.7.4
+python-multipart>=0.0.6
+ruff>=0.0.290
+bcrypt>=4.0.1
+email-validator>=2.0.0
+python-dotenv>=1.0.0