Create Small Business Inventory Management System API

- Set up project structure with FastAPI and SQLite
- Create database models for inventory management
- Set up SQLAlchemy and Alembic for database migrations
- Create initial database migrations
- Implement CRUD operations for products, categories, suppliers
- Implement stock movement tracking and inventory management
- Add authentication and user management
- Add API endpoints for all entities
- Add health check endpoint
- Update README with project information and usage instructions

README.md

@@ -1,3 +1,130 @@
-# FastAPI Application
+# Small Business Inventory Management System
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A RESTful API for small business inventory management built with FastAPI and SQLite.
+
+## Features
+
+- **User Authentication**: Secure login and role-based access control
+- **Product Management**: Add, update, and remove products with detailed information
+- **Category and Supplier Management**: Organize products by categories and suppliers
+- **Inventory Tracking**: Monitor stock levels and receive alerts for low stock
+- **Stock Movement Tracking**: Record purchases, sales, returns, and inventory adjustments
+- **Search Functionality**: Search for products, categories, and suppliers
+
+## Technical Stack
+
+- **Backend**: FastAPI (Python)
+- **Database**: SQLite
+- **ORM**: SQLAlchemy
+- **Migrations**: Alembic
+- **Authentication**: JWT (JSON Web Tokens)
+
+## API Endpoints
+
+### Authentication
+
+- `POST /api/v1/login/access-token` - Get access token
+- `POST /api/v1/login/test-token` - Test token validity
+
+### 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 information
+- `PUT /api/v1/users/me` - Update current user information
+- `GET /api/v1/users/{user_id}` - Get specific user information
+- `PUT /api/v1/users/{user_id}` - Update specific user (admin only)
+
+### Products
+
+- `GET /api/v1/products/` - List all products
+- `POST /api/v1/products/` - Create a new product
+- `GET /api/v1/products/{product_id}` - Get specific product
+- `PUT /api/v1/products/{product_id}` - Update specific product
+- `DELETE /api/v1/products/{product_id}` - Delete specific product (admin only)
+- `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/search/` - Search products
+- `GET /api/v1/products/low-stock/` - Get products with low stock
+
+### Categories
+
+- `GET /api/v1/categories/` - List all categories
+- `POST /api/v1/categories/` - Create a new category
+- `GET /api/v1/categories/{category_id}` - Get specific category
+- `PUT /api/v1/categories/{category_id}` - Update specific category
+- `DELETE /api/v1/categories/{category_id}` - Delete specific category (admin only)
+- `GET /api/v1/categories/search/` - Search categories
+
+### Suppliers
+
+- `GET /api/v1/suppliers/` - List all suppliers
+- `POST /api/v1/suppliers/` - Create a new supplier
+- `GET /api/v1/suppliers/{supplier_id}` - Get specific supplier
+- `PUT /api/v1/suppliers/{supplier_id}` - Update specific supplier
+- `DELETE /api/v1/suppliers/{supplier_id}` - Delete specific supplier (admin only)
+- `GET /api/v1/suppliers/search/` - Search suppliers
+
+### Stock Movements
+
+- `GET /api/v1/stock-movements/` - List all stock movements
+- `POST /api/v1/stock-movements/` - Create a new stock movement
+- `GET /api/v1/stock-movements/{stock_movement_id}` - Get specific stock movement
+- `GET /api/v1/stock-movements/by-product/{product_id}` - Get stock movements by product
+- `GET /api/v1/stock-movements/by-type/{movement_type}` - Get stock movements by type
+
+### Health Check
+
+- `GET /health` - Check API health status
+
+## Installation and Setup
+
+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:
+   - Swagger UI: http://localhost:8000/docs
+   - ReDoc: http://localhost:8000/redoc
+
+## Database Migrations
+
+Initialize and apply database migrations:
+
+```bash
+alembic upgrade head
+```
+
+## Creating a Superuser
+
+To create an admin user, use the following API endpoint:
+
+```
+POST /api/v1/users/
+```
+
+With the payload:
+```json
+{
+  "email": "admin@example.com",
+  "username": "admin",
+  "password": "your-secure-password",
+  "is_superuser": true
+}
+```
+
+## License
+
+This project is licensed under the MIT License - see the LICENSE file for details.

alembic.ini

@@ -0,0 +1,106 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
+# Uncomment the line below if you want the files to be prepended with date and time
+# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file
+# for all available tokens
+# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(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
+
+# SQLite URL example
+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/__init__.py

@@ -0,0 +1 @@
+# app package initialization

app/api/__init__.py

@@ -0,0 +1 @@
+# API package initialization

app/api/api_v1/__init__.py

@@ -0,0 +1 @@
+# API v1 package initialization

app/api/api_v1/api.py

@@ -0,0 +1,11 @@
+from fastapi import APIRouter
+
+from app.api.api_v1.endpoints import login, users, products, categories, suppliers, stock_movements
+
+api_router = APIRouter()
+api_router.include_router(login.router, tags=["login"])
+api_router.include_router(users.router, prefix="/users", tags=["users"])
+api_router.include_router(products.router, prefix="/products", tags=["products"])
+api_router.include_router(categories.router, prefix="/categories", tags=["categories"])
+api_router.include_router(suppliers.router, prefix="/suppliers", tags=["suppliers"])
+api_router.include_router(stock_movements.router, prefix="/stock-movements", tags=["stock-movements"])

app/api/api_v1/endpoints/categories.py

@@ -0,0 +1,120 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+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.get_by_name(db, name=category_in.name)
+    if category:
+        raise HTTPException(
+            status_code=400,
+            detail="A category with this name already exists in the system.",
+        )
+    category = crud.category.create(db, obj_in=category_in)
+    return category
+
+
+@router.get("/{category_id}", response_model=schemas.Category)
+def read_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    category_id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get category by ID.
+    """
+    category = crud.category.get(db, id=category_id)
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    return category
+
+
+@router.put("/{category_id}", response_model=schemas.Category)
+def update_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    category_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=category_id)
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    
+    # If name is being updated, check for duplicates
+    if category_in.name and category_in.name != category.name:
+        existing_category = crud.category.get_by_name(db, name=category_in.name)
+        if existing_category:
+            raise HTTPException(
+                status_code=400,
+                detail="A category with this name already exists in the system.",
+            )
+    
+    category = crud.category.update(db, db_obj=category, obj_in=category_in)
+    return category
+
+
+@router.delete("/{category_id}", response_model=schemas.Category)
+def delete_category(
+    *,
+    db: Session = Depends(deps.get_db),
+    category_id: str,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Delete a category.
+    """
+    category = crud.category.get(db, id=category_id)
+    if not category:
+        raise HTTPException(status_code=404, detail="Category not found")
+    category = crud.category.remove(db, id=category_id)
+    return category
+
+
+@router.get("/search/", response_model=List[schemas.Category])
+def search_categories(
+    *,
+    db: Session = Depends(deps.get_db),
+    query: str = Query(..., min_length=1),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Search categories by name or description.
+    """
+    categories = crud.category.search(db, query=query, skip=skip, limit=limit)
+    return categories

app/api/api_v1/endpoints/login.py

@@ -0,0 +1,44 @@
+from datetime import timedelta
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException
+from fastapi.security import OAuth2PasswordRequestForm
+from sqlalchemy.orm import Session
+
+from app import crud, models, schemas
+from app.api import deps
+from app.core import security
+from app.core.config import settings
+
+router = APIRouter()
+
+
+@router.post("/login/access-token", 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, username=form_data.username, password=form_data.password
+    )
+    if not user:
+        raise HTTPException(status_code=400, detail="Incorrect username or password")
+    elif not crud.user.is_active(user):
+        raise HTTPException(status_code=400, 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("/login/test-token", response_model=schemas.User)
+def test_token(current_user: models.User = Depends(deps.get_current_user)) -> Any:
+    """
+    Test access token
+    """
+    return current_user

app/api/api_v1/endpoints/products.py

@@ -0,0 +1,185 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+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(db, 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.
+    """
+    product = crud.product.get_by_sku(db, sku=product_in.sku)
+    if product:
+        raise HTTPException(
+            status_code=400,
+            detail="The product with this SKU already exists in the system.",
+        )
+    
+    if product_in.barcode:
+        product = crud.product.get_by_barcode(db, barcode=product_in.barcode)
+        if product:
+            raise HTTPException(
+                status_code=400,
+                detail="The product with this barcode already exists in the system.",
+            )
+    
+    product = crud.product.create(db, obj_in=product_in)
+    return product
+
+
+@router.get("/{product_id}", response_model=schemas.Product)
+def read_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    product_id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get product by ID.
+    """
+    product = crud.product.get(db, id=product_id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    return product
+
+
+@router.put("/{product_id}", response_model=schemas.Product)
+def update_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    product_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=product_id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    
+    # If SKU is being updated, check for duplicates
+    if product_in.sku and product_in.sku != product.sku:
+        existing_product = crud.product.get_by_sku(db, sku=product_in.sku)
+        if existing_product:
+            raise HTTPException(
+                status_code=400,
+                detail="The product with this SKU already exists in the system.",
+            )
+    
+    # If barcode is being updated, check for duplicates
+    if product_in.barcode and product_in.barcode != product.barcode:
+        existing_product = crud.product.get_by_barcode(db, barcode=product_in.barcode)
+        if existing_product:
+            raise HTTPException(
+                status_code=400,
+                detail="The product with this barcode already exists in the system.",
+            )
+    
+    product = crud.product.update(db, db_obj=product, obj_in=product_in)
+    return product
+
+
+@router.delete("/{product_id}", response_model=schemas.Product)
+def delete_product(
+    *,
+    db: Session = Depends(deps.get_db),
+    product_id: str,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Delete a product.
+    """
+    product = crud.product.get(db, id=product_id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    product = crud.product.remove(db, id=product_id)
+    return product
+
+
+@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:
+    """
+    Get products by category.
+    """
+    products = crud.product.get_by_category(db, category_id=category_id, skip=skip, limit=limit)
+    return products
+
+
+@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:
+    """
+    Get products by supplier.
+    """
+    products = crud.product.get_by_supplier(db, supplier_id=supplier_id, skip=skip, limit=limit)
+    return products
+
+
+@router.get("/search/", response_model=List[schemas.Product])
+def search_products(
+    *,
+    db: Session = Depends(deps.get_db),
+    query: str = Query(..., min_length=1),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Search products by name, SKU, or barcode.
+    """
+    products = crud.product.search(db, query=query, skip=skip, limit=limit)
+    return products
+
+
+@router.get("/low-stock/", response_model=List[schemas.Product])
+def get_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:
+    """
+    Get products with stock levels at or below reorder level.
+    """
+    products = crud.product.get_low_stock(db, skip=skip, limit=limit)
+    return products

app/api/api_v1/endpoints/stock_movements.py

@@ -0,0 +1,106 @@
+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.stock_movement import MovementType
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.StockMovement])
+def read_stock_movements(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Retrieve stock movements.
+    """
+    stock_movements = crud.stock_movement.get_multi(db, skip=skip, limit=limit)
+    return stock_movements
+
+
+@router.post("/", response_model=schemas.StockMovement)
+def create_stock_movement(
+    *,
+    db: Session = Depends(deps.get_db),
+    stock_movement_in: schemas.StockMovementCreate,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Create new stock movement and update product stock levels.
+    """
+    # Check if product exists
+    product = crud.product.get(db, id=stock_movement_in.product_id)
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+    
+    # For outgoing stock, make sure we have enough
+    if stock_movement_in.movement_type in [MovementType.SALE, MovementType.ADJUSTMENT] and stock_movement_in.quantity > 0:
+        if product.current_stock < stock_movement_in.quantity:
+            raise HTTPException(
+                status_code=400,
+                detail=f"Not enough stock available. Current stock: {product.current_stock}",
+            )
+    
+    # Create stock movement and update product stock level
+    stock_movement = crud.stock_movement.create_with_product_update(
+        db, obj_in=stock_movement_in, created_by=current_user.id
+    )
+    return stock_movement
+
+
+@router.get("/{stock_movement_id}", response_model=schemas.StockMovement)
+def read_stock_movement(
+    *,
+    db: Session = Depends(deps.get_db),
+    stock_movement_id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get stock movement by ID.
+    """
+    stock_movement = crud.stock_movement.get(db, id=stock_movement_id)
+    if not stock_movement:
+        raise HTTPException(status_code=404, detail="Stock movement not found")
+    return stock_movement
+
+
+@router.get("/by-product/{product_id}", response_model=List[schemas.StockMovement])
+def read_stock_movements_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:
+    """
+    Get stock movements by product.
+    """
+    stock_movements = crud.stock_movement.get_by_product(
+        db, product_id=product_id, skip=skip, limit=limit
+    )
+    return stock_movements
+
+
+@router.get("/by-type/{movement_type}", response_model=List[schemas.StockMovement])
+def read_stock_movements_by_type(
+    *,
+    db: Session = Depends(deps.get_db),
+    movement_type: MovementType,
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get stock movements by movement type.
+    """
+    stock_movements = crud.stock_movement.get_by_movement_type(
+        db, movement_type=movement_type, skip=skip, limit=limit
+    )
+    return stock_movements

app/api/api_v1/endpoints/suppliers.py

@@ -0,0 +1,138 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+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.get_by_name(db, name=supplier_in.name)
+    if supplier:
+        raise HTTPException(
+            status_code=400,
+            detail="A supplier with this name already exists in the system.",
+        )
+    
+    if supplier_in.email:
+        supplier = crud.supplier.get_by_email(db, email=supplier_in.email)
+        if supplier:
+            raise HTTPException(
+                status_code=400,
+                detail="A supplier with this email already exists in the system.",
+            )
+    
+    supplier = crud.supplier.create(db, obj_in=supplier_in)
+    return supplier
+
+
+@router.get("/{supplier_id}", response_model=schemas.Supplier)
+def read_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    supplier_id: str,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Get supplier by ID.
+    """
+    supplier = crud.supplier.get(db, id=supplier_id)
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    return supplier
+
+
+@router.put("/{supplier_id}", response_model=schemas.Supplier)
+def update_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    supplier_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=supplier_id)
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    
+    # If name is being updated, check for duplicates
+    if supplier_in.name and supplier_in.name != supplier.name:
+        existing_supplier = crud.supplier.get_by_name(db, name=supplier_in.name)
+        if existing_supplier:
+            raise HTTPException(
+                status_code=400,
+                detail="A supplier with this name already exists in the system.",
+            )
+    
+    # If email is being updated, check for duplicates
+    if supplier_in.email and supplier_in.email != supplier.email:
+        existing_supplier = crud.supplier.get_by_email(db, email=supplier_in.email)
+        if existing_supplier:
+            raise HTTPException(
+                status_code=400,
+                detail="A supplier with this email already exists in the system.",
+            )
+    
+    supplier = crud.supplier.update(db, db_obj=supplier, obj_in=supplier_in)
+    return supplier
+
+
+@router.delete("/{supplier_id}", response_model=schemas.Supplier)
+def delete_supplier(
+    *,
+    db: Session = Depends(deps.get_db),
+    supplier_id: str,
+    current_user: models.User = Depends(deps.get_current_active_superuser),
+) -> Any:
+    """
+    Delete a supplier.
+    """
+    supplier = crud.supplier.get(db, id=supplier_id)
+    if not supplier:
+        raise HTTPException(status_code=404, detail="Supplier not found")
+    supplier = crud.supplier.remove(db, id=supplier_id)
+    return supplier
+
+
+@router.get("/search/", response_model=List[schemas.Supplier])
+def search_suppliers(
+    *,
+    db: Session = Depends(deps.get_db),
+    query: str = Query(..., min_length=1),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: models.User = Depends(deps.get_current_active_user),
+) -> Any:
+    """
+    Search suppliers by name, contact name, or email.
+    """
+    suppliers = crud.supplier.search(db, query=query, skip=skip, limit=limit)
+    return suppliers

app/api/api_v1/endpoints/users.py

@@ -0,0 +1,125 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Body, Depends, HTTPException
+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="The user with this email already exists in the system.",
+        )
+    user = crud.user.get_by_username(db, username=user_in.username)
+    if user:
+        raise HTTPException(
+            status_code=400,
+            detail="The user with this username already exists in the system.",
+        )
+    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=400, 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/api/deps.py

@@ -0,0 +1,49 @@
+
+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.config import settings
+from app.db.session import get_db
+
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl=f"{settings.API_V1_STR}/login/access-token")
+
+
+def get_current_user(
+    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
+) -> models.User:
+    try:
+        payload = jwt.decode(
+            token, settings.SECRET_KEY, algorithms=[settings.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:
+    if not crud.user.is_active(current_user):
+        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:
+    if not crud.user.is_superuser(current_user):
+        raise HTTPException(
+            status_code=400, detail="The user doesn't have enough privileges"
+        )
+    return current_user

app/core/config.py

@@ -0,0 +1,24 @@
+from pydantic_settings import BaseSettings
+from pathlib import Path
+
+
+class Settings(BaseSettings):
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Small Business Inventory Management System"
+    
+    # Security
+    SECRET_KEY: str = "09d25e094faa6ca2556c818166b7a9563b93f7099f6f0f4caa6cf63b88e8d3e7"
+    ALGORITHM: str = "HS256"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
+    
+    # Database
+    DB_DIR: Path = Path("/app") / "storage" / "db"
+    
+    class Config:
+        case_sensitive = True
+
+
+settings = Settings()
+
+# Create database directory if it doesn't exist
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)

app/core/security.py

@@ -0,0 +1,31 @@
+from datetime import datetime, timedelta
+from typing import Any, Union
+
+from jose import jwt
+from passlib.context import CryptContext
+
+from app.core.config import settings
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+
+def create_access_token(
+    subject: Union[str, Any], expires_delta: timedelta = None
+) -> str:
+    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=settings.ALGORITHM)
+    return encoded_jwt
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    return pwd_context.hash(password)

app/crud/__init__.py

@@ -0,0 +1,8 @@
+# Re-export CRUD instances for easy access
+from app.crud.crud_user import user as user
+from app.crud.crud_product import product as product
+from app.crud.crud_category import category as category
+from app.crud.crud_supplier import supplier as supplier
+from app.crud.crud_stock_movement import stock_movement as stock_movement
+
+__all__ = ["user", "product", "category", "supplier", "stock_movement"]

app/crud/base.py

@@ -0,0 +1,68 @@
+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
+import uuid
+
+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]):
+    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]:
+        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]:
+        return db.query(self.model).offset(skip).limit(limit).all()
+
+    def create(self, db: Session, *, obj_in: CreateSchemaType) -> ModelType:
+        obj_in_data = jsonable_encoder(obj_in)
+        # Generate a UUID string for new object
+        obj_in_data["id"] = str(uuid.uuid4())
+        db_obj = self.model(**obj_in_data)
+        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:
+        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: str) -> ModelType:
+        obj = db.query(self.model).get(id)
+        db.delete(obj)
+        db.commit()
+        return obj

app/crud/crud_category.py

@@ -0,0 +1,20 @@
+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]):
+    def get_by_name(self, db: Session, *, name: str) -> Optional[Category]:
+        return db.query(Category).filter(Category.name == name).first()
+    
+    def search(self, db: Session, *, query: str, skip: int = 0, limit: int = 100) -> List[Category]:
+        return db.query(Category).filter(
+            Category.name.ilike(f"%{query}%") | 
+            Category.description.ilike(f"%{query}%")
+        ).offset(skip).limit(limit).all()
+
+
+category = CRUDCategory(Category)

app/crud/crud_product.py

@@ -0,0 +1,42 @@
+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]):
+    def get_by_sku(self, db: Session, *, sku: str) -> Optional[Product]:
+        return db.query(Product).filter(Product.sku == sku).first()
+    
+    def get_by_barcode(self, db: Session, *, barcode: str) -> Optional[Product]:
+        return db.query(Product).filter(Product.barcode == barcode).first()
+    
+    def get_by_category(self, db: Session, *, category_id: str, skip: int = 0, limit: int = 100) -> List[Product]:
+        return db.query(Product).filter(Product.category_id == category_id).offset(skip).limit(limit).all()
+    
+    def get_by_supplier(self, db: Session, *, supplier_id: str, skip: int = 0, limit: int = 100) -> List[Product]:
+        return db.query(Product).filter(Product.supplier_id == supplier_id).offset(skip).limit(limit).all()
+    
+    def get_low_stock(self, db: Session, *, skip: int = 0, limit: int = 100) -> List[Product]:
+        return db.query(Product).filter(Product.current_stock <= Product.reorder_level).offset(skip).limit(limit).all()
+    
+    def search(self, db: Session, *, query: str, skip: int = 0, limit: int = 100) -> List[Product]:
+        return db.query(Product).filter(
+            Product.name.ilike(f"%{query}%") | 
+            Product.sku.ilike(f"%{query}%") | 
+            Product.barcode.ilike(f"%{query}%")
+        ).offset(skip).limit(limit).all()
+    
+    def update_stock(self, db: Session, *, product_id: str, quantity: int) -> Product:
+        product = self.get(db, id=product_id)
+        if product:
+            product.current_stock += quantity
+            db.add(product)
+            db.commit()
+            db.refresh(product)
+        return product
+
+
+product = CRUDProduct(Product)

app/crud/crud_stock_movement.py

@@ -0,0 +1,54 @@
+from typing import List, Optional
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.stock_movement import StockMovement, MovementType
+from app.schemas.stock_movement import StockMovementCreate
+from app.crud.crud_product import product as product_crud
+
+
+class CRUDStockMovement(CRUDBase[StockMovement, StockMovementCreate, StockMovementCreate]):
+    def create_with_product_update(
+        self, db: Session, *, obj_in: StockMovementCreate, created_by: Optional[str] = None
+    ) -> StockMovement:
+        # Create the stock movement
+        obj_in_data = obj_in.dict()
+        obj_in_data["created_by"] = created_by
+        db_obj = super().create(db, obj_in=obj_in)
+        
+        # Update product stock level
+        quantity = obj_in.quantity
+        if obj_in.movement_type in [MovementType.SALE, MovementType.ADJUSTMENT]:
+            if obj_in.quantity > 0:
+                quantity = -quantity  # Negate for outgoing stock
+        
+        product_crud.update_stock(db, product_id=obj_in.product_id, quantity=quantity)
+        
+        return db_obj
+    
+    def get_by_product(
+        self, db: Session, *, product_id: str, skip: int = 0, limit: int = 100
+    ) -> List[StockMovement]:
+        return (
+            db.query(StockMovement)
+            .filter(StockMovement.product_id == product_id)
+            .order_by(StockMovement.created_at.desc())
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+    
+    def get_by_movement_type(
+        self, db: Session, *, movement_type: MovementType, skip: int = 0, limit: int = 100
+    ) -> List[StockMovement]:
+        return (
+            db.query(StockMovement)
+            .filter(StockMovement.movement_type == movement_type)
+            .order_by(StockMovement.created_at.desc())
+            .offset(skip)
+            .limit(limit)
+            .all()
+        )
+
+
+stock_movement = CRUDStockMovement(StockMovement)

app/crud/crud_supplier.py

@@ -0,0 +1,24 @@
+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]):
+    def get_by_name(self, db: Session, *, name: str) -> Optional[Supplier]:
+        return db.query(Supplier).filter(Supplier.name == name).first()
+    
+    def get_by_email(self, db: Session, *, email: str) -> Optional[Supplier]:
+        return db.query(Supplier).filter(Supplier.email == email).first()
+    
+    def search(self, db: Session, *, query: str, skip: int = 0, limit: int = 100) -> List[Supplier]:
+        return db.query(Supplier).filter(
+            Supplier.name.ilike(f"%{query}%") | 
+            Supplier.contact_name.ilike(f"%{query}%") | 
+            Supplier.email.ilike(f"%{query}%")
+        ).offset(skip).limit(limit).all()
+
+
+supplier = CRUDSupplier(Supplier)

app/crud/crud_user.py

@@ -0,0 +1,59 @@
+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]):
+    def get_by_email(self, db: Session, *, email: str) -> Optional[User]:
+        return db.query(User).filter(User.email == email).first()
+    
+    def get_by_username(self, db: Session, *, username: str) -> Optional[User]:
+        return db.query(User).filter(User.username == username).first()
+
+    def create(self, db: Session, *, obj_in: UserCreate) -> User:
+        db_obj = User(
+            email=obj_in.email,
+            username=obj_in.username,
+            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:
+        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, *, username: str, password: str) -> Optional[User]:
+        user = self.get_by_username(db, username=username)
+        if not user:
+            return None
+        if not verify_password(password, user.hashed_password):
+            return None
+        return user
+
+    def is_active(self, user: User) -> bool:
+        return user.is_active
+
+    def is_superuser(self, user: User) -> bool:
+        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.product import Product  # noqa
+from app.models.category import Category  # noqa
+from app.models.supplier import Supplier  # noqa
+from app.models.stock_movement import StockMovement  # noqa

app/db/base_class.py

@@ -0,0 +1,13 @@
+from typing import Any
+from sqlalchemy.ext.declarative import declared_attr
+from sqlalchemy.orm import DeclarativeBase
+
+
+class Base(DeclarativeBase):
+    id: Any
+    __name__: str
+    
+    # Generate __tablename__ automatically
+    @declared_attr
+    def __tablename__(cls) -> str:
+        return cls.__name__.lower()

app/db/session.py

@@ -0,0 +1,24 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+# Ensure the database directory exists
+DB_DIR = settings.DB_DIR
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/category.py

@@ -0,0 +1,12 @@
+from sqlalchemy import Column, String, DateTime, Text
+from sqlalchemy.sql import func
+
+from app.db.base_class import Base
+
+
+class Category(Base):
+    id = Column(String, primary_key=True, index=True)
+    name = Column(String, index=True, nullable=False)
+    description = Column(Text, nullable=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

app/models/product.py

@@ -0,0 +1,30 @@
+from sqlalchemy import Column, String, Integer, Float, DateTime, Text, ForeignKey, Boolean
+from sqlalchemy.sql import func
+from sqlalchemy.orm import relationship
+
+from app.db.base_class import Base
+
+
+class Product(Base):
+    id = Column(String, primary_key=True, index=True)
+    name = Column(String, index=True, nullable=False)
+    description = Column(Text, nullable=True)
+    sku = Column(String, unique=True, index=True, nullable=False)
+    barcode = Column(String, unique=True, nullable=True)
+    
+    category_id = Column(String, ForeignKey("category.id"), nullable=True)
+    category = relationship("Category", backref="products")
+    
+    supplier_id = Column(String, ForeignKey("supplier.id"), nullable=True)
+    supplier = relationship("Supplier", backref="products")
+    
+    cost_price = Column(Float, nullable=False, default=0.0)
+    selling_price = Column(Float, nullable=False, default=0.0)
+    
+    current_stock = Column(Integer, nullable=False, default=0)
+    reorder_level = Column(Integer, nullable=False, default=0)
+    
+    is_active = Column(Boolean, default=True)
+    
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

app/models/stock_movement.py

@@ -0,0 +1,35 @@
+from sqlalchemy import Column, String, Integer, Float, DateTime, Text, ForeignKey, Enum
+from sqlalchemy.sql import func
+from sqlalchemy.orm import relationship
+import enum
+
+from app.db.base_class import Base
+
+
+class MovementType(str, enum.Enum):
+    PURCHASE = "purchase"
+    SALE = "sale"
+    ADJUSTMENT = "adjustment"
+    RETURN = "return"
+    INITIAL = "initial"
+
+
+class StockMovement(Base):
+    id = Column(String, primary_key=True, index=True)
+    
+    product_id = Column(String, ForeignKey("product.id"), nullable=False)
+    product = relationship("Product", backref="stock_movements")
+    
+    quantity = Column(Integer, nullable=False)
+    unit_price = Column(Float, nullable=True)
+    
+    movement_type = Column(Enum(MovementType), nullable=False)
+    reference = Column(String, nullable=True)  # Reference to purchase order, invoice, etc.
+    
+    notes = Column(Text, nullable=True)
+    
+    created_by = Column(String, ForeignKey("user.id"), nullable=True)
+    user = relationship("User", backref="stock_movements")
+    
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

app/models/supplier.py

@@ -0,0 +1,16 @@
+from sqlalchemy import Column, String, DateTime, Text
+from sqlalchemy.sql import func
+
+from app.db.base_class import Base
+
+
+class Supplier(Base):
+    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(Text, nullable=True)
+    notes = Column(Text, nullable=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

app/models/user.py

@@ -0,0 +1,16 @@
+from sqlalchemy import Boolean, Column, String, DateTime
+from sqlalchemy.sql import func
+
+from app.db.base_class import Base
+
+
+class User(Base):
+    id = Column(String, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True, nullable=False)
+    username = Column(String, unique=True, index=True, nullable=False)
+    hashed_password = Column(String, nullable=False)
+    full_name = Column(String, nullable=True)
+    is_active = Column(Boolean, default=True)
+    is_superuser = Column(Boolean, default=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())

app/schemas/__init__.py

@@ -0,0 +1,14 @@
+# Re-export schemas for easy access
+from app.schemas.user import User as User, UserCreate as UserCreate, UserUpdate as UserUpdate, Token as Token, TokenPayload as TokenPayload
+from app.schemas.product import Product as Product, ProductCreate as ProductCreate, ProductUpdate as ProductUpdate
+from app.schemas.category import Category as Category, CategoryCreate as CategoryCreate, CategoryUpdate as CategoryUpdate
+from app.schemas.supplier import Supplier as Supplier, SupplierCreate as SupplierCreate, SupplierUpdate as SupplierUpdate
+from app.schemas.stock_movement import StockMovement as StockMovement, StockMovementCreate as StockMovementCreate
+
+__all__ = [
+    "User", "UserCreate", "UserUpdate", "Token", "TokenPayload",
+    "Product", "ProductCreate", "ProductUpdate",
+    "Category", "CategoryCreate", "CategoryUpdate",
+    "Supplier", "SupplierCreate", "SupplierUpdate",
+    "StockMovement", "StockMovementCreate"
+]

app/schemas/category.py

@@ -0,0 +1,33 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+
+
+# Shared properties
+class CategoryBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class CategoryCreate(CategoryBase):
+    pass
+
+
+# Properties to receive via API on update
+class CategoryUpdate(CategoryBase):
+    name: Optional[str] = None
+
+
+class CategoryInDBBase(CategoryBase):
+    id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class Category(CategoryInDBBase):
+    pass

app/schemas/product.py

@@ -0,0 +1,45 @@
+from pydantic import BaseModel, Field
+from typing import Optional
+from datetime import datetime
+
+
+# Shared properties
+class ProductBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+    sku: str
+    barcode: Optional[str] = None
+    category_id: Optional[str] = None
+    supplier_id: Optional[str] = None
+    cost_price: float = Field(ge=0)
+    selling_price: float = Field(ge=0)
+    reorder_level: int = Field(ge=0, default=0)
+    is_active: bool = True
+
+
+# Properties to receive via API on creation
+class ProductCreate(ProductBase):
+    pass
+
+
+# Properties to receive via API on update
+class ProductUpdate(ProductBase):
+    name: Optional[str] = None
+    sku: Optional[str] = None
+    cost_price: Optional[float] = None
+    selling_price: Optional[float] = None
+
+
+class ProductInDBBase(ProductBase):
+    id: str
+    current_stock: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class Product(ProductInDBBase):
+    pass

app/schemas/stock_movement.py

@@ -0,0 +1,34 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+from app.models.stock_movement import MovementType
+
+
+# Shared properties
+class StockMovementBase(BaseModel):
+    product_id: str
+    quantity: int
+    unit_price: Optional[float] = None
+    movement_type: MovementType
+    reference: Optional[str] = None
+    notes: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class StockMovementCreate(StockMovementBase):
+    pass
+
+
+class StockMovementInDBBase(StockMovementBase):
+    id: str
+    created_by: Optional[str] = None
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class StockMovement(StockMovementInDBBase):
+    pass

app/schemas/supplier.py

@@ -0,0 +1,37 @@
+from pydantic import BaseModel, EmailStr
+from typing import Optional
+from datetime import datetime
+
+
+# Shared properties
+class SupplierBase(BaseModel):
+    name: str
+    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):
+    pass
+
+
+# Properties to receive via API on update
+class SupplierUpdate(SupplierBase):
+    name: Optional[str] = None
+
+
+class SupplierInDBBase(SupplierBase):
+    id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class Supplier(SupplierInDBBase):
+    pass

app/schemas/user.py

@@ -0,0 +1,53 @@
+from pydantic import BaseModel, EmailStr
+from typing import Optional
+from datetime import datetime
+
+
+# Shared properties
+class UserBase(BaseModel):
+    email: Optional[EmailStr] = None
+    username: Optional[str] = None
+    is_active: Optional[bool] = True
+    is_superuser: bool = False
+    full_name: Optional[str] = None
+
+
+# Properties to receive via API on creation
+class UserCreate(UserBase):
+    email: EmailStr
+    username: str
+    password: str
+
+
+# Properties to receive via API on update
+class UserUpdate(UserBase):
+    password: Optional[str] = None
+
+
+class UserInDBBase(UserBase):
+    id: str
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Additional properties to return via API
+class User(UserInDBBase):
+    pass
+
+
+# Additional properties stored in DB
+class UserInDB(UserInDBBase):
+    hashed_password: str
+
+
+class Token(BaseModel):
+    access_token: str
+    token_type: str
+
+
+class TokenPayload(BaseModel):
+    sub: str = None
+    exp: int = None

main.py

@@ -0,0 +1,24 @@
+import uvicorn
+from fastapi import FastAPI
+
+from app.api.api_v1.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    description="Small Business Inventory Management System API",
+    version="0.1.0"
+)
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+@app.get("/health", tags=["health"])
+async def health_check():
+    """
+    Health check endpoint to verify the application is running
+    """
+    return {"status": "healthy"}
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/README

@@ -0,0 +1 @@
+Generic single-database configuration for Alembic.

migrations/env.py

@@ -0,0 +1,80 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+from app.db.base import Base
+
+# 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)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+target_metadata = Base.metadata
+
+# 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 = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    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.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Key configuration for 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() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

migrations/versions/2023_11_24_initial_schema.py

@@ -0,0 +1,117 @@
+"""Initial schema
+
+Revision ID: 2023_11_24_initial
+Revises: 
+Create Date: 2023-11-24
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.sql import func
+import enum
+
+
+# revision identifiers, used by Alembic.
+revision = '2023_11_24_initial'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+class MovementType(str, enum.Enum):
+    PURCHASE = "purchase"
+    SALE = "sale"
+    ADJUSTMENT = "adjustment"
+    RETURN = "return"
+    INITIAL = "initial"
+
+
+def upgrade() -> None:
+    # Create user table
+    op.create_table(
+        'user',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('email', sa.String(), unique=True, index=True, nullable=False),
+        sa.Column('username', sa.String(), unique=True, index=True, nullable=False),
+        sa.Column('hashed_password', sa.String(), nullable=False),
+        sa.Column('full_name', sa.String(), nullable=True),
+        sa.Column('is_active', sa.Boolean(), default=True),
+        sa.Column('is_superuser', sa.Boolean(), default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+    )
+    
+    # Create category table
+    op.create_table(
+        'category',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('name', sa.String(), index=True, nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+    )
+    
+    # Create supplier table
+    op.create_table(
+        'supplier',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('name', sa.String(), index=True, nullable=False),
+        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.Text(), nullable=True),
+        sa.Column('notes', sa.Text(), nullable=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+    )
+    
+    # Create product table
+    op.create_table(
+        'product',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('name', sa.String(), index=True, nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('sku', sa.String(), unique=True, index=True, nullable=False),
+        sa.Column('barcode', sa.String(), unique=True, nullable=True),
+        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('cost_price', sa.Float(), nullable=False, default=0.0),
+        sa.Column('selling_price', sa.Float(), nullable=False, default=0.0),
+        sa.Column('current_stock', sa.Integer(), nullable=False, default=0),
+        sa.Column('reorder_level', sa.Integer(), nullable=False, default=0),
+        sa.Column('is_active', sa.Boolean(), default=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+    )
+    
+    # Create stock_movement table
+    op.create_table(
+        'stockmovement',
+        sa.Column('id', sa.String(), primary_key=True, index=True),
+        sa.Column('product_id', sa.String(), sa.ForeignKey("product.id"), nullable=False),
+        sa.Column('quantity', sa.Integer(), nullable=False),
+        sa.Column('unit_price', sa.Float(), nullable=True),
+        sa.Column('movement_type', sa.Enum(MovementType), nullable=False),
+        sa.Column('reference', sa.String(), nullable=True),
+        sa.Column('notes', sa.Text(), nullable=True),
+        sa.Column('created_by', sa.String(), sa.ForeignKey("user.id"), nullable=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+    )
+    
+    # Create indexes
+    op.create_index(op.f('ix_product_name'), 'product', ['name'], unique=False)
+    op.create_index(op.f('ix_product_sku'), 'product', ['sku'], unique=True)
+    op.create_index(op.f('ix_category_name'), 'category', ['name'], unique=False)
+    op.create_index(op.f('ix_supplier_name'), 'supplier', ['name'], unique=False)
+    op.create_index(op.f('ix_user_email'), 'user', ['email'], unique=True)
+    op.create_index(op.f('ix_user_username'), 'user', ['username'], unique=True)
+
+
+def downgrade() -> None:
+    # Drop tables in reverse order of creation
+    op.drop_table('stockmovement')
+    op.drop_table('product')
+    op.drop_table('supplier')
+    op.drop_table('category')
+    op.drop_table('user')

requirements.txt

@@ -0,0 +1,11 @@
+fastapi==0.104.1
+uvicorn==0.23.2
+sqlalchemy==2.0.23
+alembic==1.12.1
+pydantic==2.4.2
+pydantic-settings==2.0.3
+python-jose==3.3.0
+passlib==1.7.4
+python-multipart==0.0.6
+bcrypt==4.0.1
+ruff==0.1.5