Implement small business inventory management system

- Create project structure with FastAPI and SQLAlchemy
- Implement database models for items, categories, suppliers, and stock movements
- Add CRUD operations for all models
- Configure Alembic for database migrations
- Create RESTful API endpoints for inventory management
- Add health endpoint for system monitoring
- Update README with setup and usage instructions

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,161 @@
-# 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 managing inventory for small businesses built with FastAPI and SQLite.
+
+## Features
+
+- Inventory item management (create, read, update, delete)
+- Category management
+- Supplier management
+- Stock movement tracking (purchases, sales, returns, adjustments)
+- Low stock alerts
+- Detailed reporting capabilities
+
+## Tech Stack
+
+- Python 3.8+
+- FastAPI
+- SQLAlchemy ORM
+- SQLite Database
+- Alembic Migrations
+- Pydantic Data Validation
+
+## Setup Instructions
+
+### Prerequisites
+
+- Python 3.8 or higher
+- pip (Python package manager)
+
+### Installation
+
+1. Clone the repository:
+```bash
+git clone https://github.com/yourusername/small-business-inventory.git
+cd small-business-inventory
+```
+
+2. Create a virtual environment:
+```bash
+python -m venv venv
+source venv/bin/activate  # On Windows: venv\Scripts\activate
+```
+
+3. Install dependencies:
+```bash
+pip install -r requirements.txt
+```
+
+4. Set up the database:
+```bash
+# Run the database migrations
+alembic upgrade head
+```
+
+### Running the Application
+
+1. Start the FastAPI server:
+```bash
+uvicorn main:app --reload
+```
+
+2. Access the API:
+   - API Documentation: http://localhost:8000/docs
+   - API Endpoints: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Health Check
+- `GET /health` - Check system health
+
+### Categories
+- `GET /categories` - List all categories
+- `GET /categories/{category_id}` - Get a specific category
+- `POST /categories` - Create a new category
+- `PUT /categories/{category_id}` - Update a category
+- `DELETE /categories/{category_id}` - Delete a category
+
+### Suppliers
+- `GET /suppliers` - List all suppliers
+- `GET /suppliers/{supplier_id}` - Get a specific supplier
+- `POST /suppliers` - Create a new supplier
+- `PUT /suppliers/{supplier_id}` - Update a supplier
+- `DELETE /suppliers/{supplier_id}` - Delete a supplier
+
+### Inventory Items
+- `GET /items` - List all inventory items (with filtering options)
+- `GET /items/{item_id}` - Get a specific item
+- `POST /items` - Create a new item
+- `PUT /items/{item_id}` - Update an item
+- `DELETE /items/{item_id}` - Delete an item
+
+### Stock Management
+- `GET /stock/movements` - List all stock movements
+- `GET /stock/movements/{movement_id}` - Get a specific stock movement
+- `POST /stock/movements` - Create a new stock movement
+- `GET /stock/low-stock` - Get low stock items
+
+## Data Models
+
+### Category
+```json
+{
+  "id": 1,
+  "name": "Electronics",
+  "description": "Electronic components and devices",
+  "is_active": true,
+  "created_at": "2025-05-12T10:00:00",
+  "updated_at": "2025-05-12T10:00:00"
+}
+```
+
+### Supplier
+```json
+{
+  "id": 1,
+  "name": "ABC Supplies",
+  "contact_name": "John Doe",
+  "email": "john@abcsupplies.com",
+  "phone": "555-1234",
+  "address": "123 Main St, Anytown",
+  "is_active": true,
+  "created_at": "2025-05-12T10:00:00",
+  "updated_at": "2025-05-12T10:00:00"
+}
+```
+
+### Item
+```json
+{
+  "id": 1,
+  "name": "LED Monitor",
+  "sku": "MON-LED-24",
+  "description": "24-inch LED Monitor",
+  "unit_price": 199.99,
+  "quantity": 25,
+  "reorder_level": 5,
+  "category_id": 1,
+  "supplier_id": 1,
+  "is_active": true,
+  "created_at": "2025-05-12T10:00:00",
+  "updated_at": "2025-05-12T10:00:00"
+}
+```
+
+### StockMovement
+```json
+{
+  "id": 1,
+  "item_id": 1,
+  "quantity": 10,
+  "movement_type": "purchase",
+  "reference": "PO12345",
+  "notes": "Initial stock order",
+  "unit_price": 180.00,
+  "created_at": "2025-05-12T10:00:00"
+}
+```
+
+## License
+
+MIT

alembic.ini

@@ -0,0 +1,107 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = alembic
+
+# 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 alembic/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:alembic/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.
+
+# set to 'true' to search source files recursively
+# in each "version_locations" directory
+# new in Alembic version 1.10
+# recursive_version_locations = false
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+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

alembic/env.py

@@ -0,0 +1,77 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# 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.
+fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+
+from app.models import Base
+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():
+    """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():
+    """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:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

alembic/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"}

alembic/versions/0001_initial_tables.py

@@ -0,0 +1,95 @@
+"""initial tables
+
+Revision ID: 0001
+Revises: 
+Create Date: 2025-05-12
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.sql import func
+
+
+# revision identifiers, used by Alembic.
+revision = '0001'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Create categories table
+    op.create_table('categories',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('is_active', sa.Boolean(), nullable=True, default=True),
+        sa.Column('created_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.Column('updated_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.PrimaryKeyConstraint('id'),
+        sa.UniqueConstraint('name')
+    )
+    op.create_index(op.f('ix_categories_id'), 'categories', ['id'], unique=False)
+    
+    # Create suppliers table
+    op.create_table('suppliers',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('name', sa.String(), 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.String(), nullable=True),
+        sa.Column('is_active', sa.Boolean(), nullable=True, default=True),
+        sa.Column('created_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.Column('updated_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.PrimaryKeyConstraint('id'),
+        sa.UniqueConstraint('name')
+    )
+    op.create_index(op.f('ix_suppliers_id'), 'suppliers', ['id'], unique=False)
+    
+    # Create items table
+    op.create_table('items',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('sku', sa.String(), nullable=False),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('unit_price', sa.Float(), nullable=False, default=0.0),
+        sa.Column('quantity', sa.Integer(), nullable=False, default=0),
+        sa.Column('reorder_level', sa.Integer(), nullable=False, default=0),
+        sa.Column('category_id', sa.Integer(), nullable=True),
+        sa.Column('supplier_id', sa.Integer(), nullable=True),
+        sa.Column('is_active', sa.Boolean(), nullable=True, default=True),
+        sa.Column('created_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.Column('updated_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.ForeignKeyConstraint(['category_id'], ['categories.id'], ),
+        sa.ForeignKeyConstraint(['supplier_id'], ['suppliers.id'], ),
+        sa.PrimaryKeyConstraint('id'),
+        sa.UniqueConstraint('sku')
+    )
+    op.create_index(op.f('ix_items_id'), 'items', ['id'], unique=False)
+    
+    # Create stock_movements table
+    op.create_table('stock_movements',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('item_id', sa.Integer(), nullable=False),
+        sa.Column('quantity', sa.Integer(), nullable=False),
+        sa.Column('movement_type', sa.Enum('purchase', 'sale', 'adjustment', 'return', name='movementtype'), nullable=False),
+        sa.Column('reference', sa.String(), nullable=True),
+        sa.Column('notes', sa.String(), nullable=True),
+        sa.Column('unit_price', sa.Float(), nullable=True),
+        sa.Column('created_at', sa.TIMESTAMP(timezone=True), server_default=func.now(), nullable=True),
+        sa.ForeignKeyConstraint(['item_id'], ['items.id'], ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_stock_movements_id'), 'stock_movements', ['id'], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f('ix_stock_movements_id'), table_name='stock_movements')
+    op.drop_table('stock_movements')
+    op.drop_index(op.f('ix_items_id'), table_name='items')
+    op.drop_table('items')
+    op.drop_index(op.f('ix_suppliers_id'), table_name='suppliers')
+    op.drop_table('suppliers')
+    op.drop_index(op.f('ix_categories_id'), table_name='categories')
+    op.drop_table('categories')

app/crud/__init__.py

@@ -0,0 +1,4 @@
+from app.crud.item import get_items, get_item, get_item_by_sku, create_item, update_item, delete_item, update_item_quantity
+from app.crud.category import get_categories, get_category, get_category_by_name, create_category, update_category, delete_category
+from app.crud.supplier import get_suppliers, get_supplier, get_supplier_by_name, create_supplier, update_supplier, delete_supplier
+from app.crud.stock_movement import get_stock_movements, get_stock_movement, create_stock_movement

app/crud/category.py

@@ -0,0 +1,54 @@
+from sqlalchemy.orm import Session
+from fastapi import HTTPException, status
+from app.models.category import Category
+from app.schemas.category import CategoryCreate, CategoryUpdate
+
+def get_categories(db: Session, skip: int = 0, limit: int = 100, include_inactive: bool = False):
+    query = db.query(Category)
+    if not include_inactive:
+        query = query.filter(Category.is_active == True)
+    return query.offset(skip).limit(limit).all()
+
+def get_category(db: Session, category_id: int):
+    return db.query(Category).filter(Category.id == category_id).first()
+
+def get_category_by_name(db: Session, name: str):
+    return db.query(Category).filter(Category.name == name).first()
+
+def create_category(db: Session, category: CategoryCreate):
+    existing_category = get_category_by_name(db, category.name)
+    if existing_category:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Category with this name already exists")
+    
+    db_category = Category(**category.model_dump())
+    db.add(db_category)
+    db.commit()
+    db.refresh(db_category)
+    return db_category
+
+def update_category(db: Session, category_id: int, category: CategoryUpdate):
+    db_category = get_category(db, category_id)
+    if not db_category:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Category not found")
+    
+    if category.name and category.name != db_category.name:
+        existing_category = get_category_by_name(db, category.name)
+        if existing_category:
+            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Category with this name already exists")
+    
+    update_data = category.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_category, key, value)
+    
+    db.commit()
+    db.refresh(db_category)
+    return db_category
+
+def delete_category(db: Session, category_id: int):
+    db_category = get_category(db, category_id)
+    if not db_category:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Category not found")
+    
+    db_category.is_active = False
+    db.commit()
+    return {"message": "Category deleted successfully"}

app/crud/item.py

@@ -0,0 +1,72 @@
+from sqlalchemy.orm import Session
+from fastapi import HTTPException, status
+from app.models.item import Item
+from app.schemas.item import ItemCreate, ItemUpdate
+
+def get_items(db: Session, skip: int = 0, limit: int = 100, category_id: int = None, 
+              supplier_id: int = None, include_inactive: bool = False):
+    query = db.query(Item)
+    
+    if category_id:
+        query = query.filter(Item.category_id == category_id)
+    
+    if supplier_id:
+        query = query.filter(Item.supplier_id == supplier_id)
+    
+    if not include_inactive:
+        query = query.filter(Item.is_active == True)
+        
+    return query.offset(skip).limit(limit).all()
+
+def get_item(db: Session, item_id: int):
+    return db.query(Item).filter(Item.id == item_id).first()
+
+def get_item_by_sku(db: Session, sku: str):
+    return db.query(Item).filter(Item.sku == sku).first()
+
+def create_item(db: Session, item: ItemCreate):
+    existing_item = get_item_by_sku(db, item.sku)
+    if existing_item:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Item with this SKU already exists")
+    
+    db_item = Item(**item.model_dump())
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+def update_item(db: Session, item_id: int, item: ItemUpdate):
+    db_item = get_item(db, item_id)
+    if not db_item:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Item not found")
+    
+    update_data = item.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_item, key, value)
+    
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+def delete_item(db: Session, item_id: int):
+    db_item = get_item(db, item_id)
+    if not db_item:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Item not found")
+    
+    db_item.is_active = False
+    db.commit()
+    return {"message": "Item deleted successfully"}
+
+def update_item_quantity(db: Session, item_id: int, quantity_change: int):
+    db_item = get_item(db, item_id)
+    if not db_item:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Item not found")
+    
+    new_quantity = db_item.quantity + quantity_change
+    if new_quantity < 0:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Insufficient stock")
+    
+    db_item.quantity = new_quantity
+    db.commit()
+    db.refresh(db_item)
+    return db_item

app/crud/stock_movement.py

@@ -0,0 +1,40 @@
+from sqlalchemy.orm import Session
+from fastapi import HTTPException, status
+from app.models.stock_movement import StockMovement
+from app.schemas.stock_movement import StockMovementCreate
+from app.crud.item import update_item_quantity, get_item
+
+def get_stock_movements(db: Session, skip: int = 0, limit: int = 100, item_id: int = None):
+    query = db.query(StockMovement)
+    
+    if item_id:
+        query = query.filter(StockMovement.item_id == item_id)
+    
+    return query.order_by(StockMovement.created_at.desc()).offset(skip).limit(limit).all()
+
+def get_stock_movement(db: Session, movement_id: int):
+    return db.query(StockMovement).filter(StockMovement.id == movement_id).first()
+
+def create_stock_movement(db: Session, movement: StockMovementCreate):
+    # Check if item exists
+    item = get_item(db, movement.item_id)
+    if not item:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Item not found")
+    
+    # Create stock movement record
+    db_movement = StockMovement(**movement.model_dump())
+    db.add(db_movement)
+    
+    # Update item quantity based on movement type
+    quantity_change = movement.quantity
+    if movement.movement_type in ["sale", "adjustment"] and quantity_change > 0:
+        quantity_change = -quantity_change
+    elif movement.movement_type in ["purchase", "return"] and quantity_change < 0:
+        quantity_change = abs(quantity_change)
+    
+    # Update the item quantity
+    update_item_quantity(db, movement.item_id, quantity_change)
+    
+    db.commit()
+    db.refresh(db_movement)
+    return db_movement

app/crud/supplier.py

@@ -0,0 +1,54 @@
+from sqlalchemy.orm import Session
+from fastapi import HTTPException, status
+from app.models.supplier import Supplier
+from app.schemas.supplier import SupplierCreate, SupplierUpdate
+
+def get_suppliers(db: Session, skip: int = 0, limit: int = 100, include_inactive: bool = False):
+    query = db.query(Supplier)
+    if not include_inactive:
+        query = query.filter(Supplier.is_active == True)
+    return query.offset(skip).limit(limit).all()
+
+def get_supplier(db: Session, supplier_id: int):
+    return db.query(Supplier).filter(Supplier.id == supplier_id).first()
+
+def get_supplier_by_name(db: Session, name: str):
+    return db.query(Supplier).filter(Supplier.name == name).first()
+
+def create_supplier(db: Session, supplier: SupplierCreate):
+    existing_supplier = get_supplier_by_name(db, supplier.name)
+    if existing_supplier:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Supplier with this name already exists")
+    
+    db_supplier = Supplier(**supplier.model_dump())
+    db.add(db_supplier)
+    db.commit()
+    db.refresh(db_supplier)
+    return db_supplier
+
+def update_supplier(db: Session, supplier_id: int, supplier: SupplierUpdate):
+    db_supplier = get_supplier(db, supplier_id)
+    if not db_supplier:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Supplier not found")
+    
+    if supplier.name and supplier.name != db_supplier.name:
+        existing_supplier = get_supplier_by_name(db, supplier.name)
+        if existing_supplier:
+            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Supplier with this name already exists")
+    
+    update_data = supplier.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_supplier, key, value)
+    
+    db.commit()
+    db.refresh(db_supplier)
+    return db_supplier
+
+def delete_supplier(db: Session, supplier_id: int):
+    db_supplier = get_supplier(db, supplier_id)
+    if not db_supplier:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Supplier not found")
+    
+    db_supplier.is_active = False
+    db.commit()
+    return {"message": "Supplier deleted successfully"}

app/database.py

@@ -0,0 +1,27 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+# Create database directory
+DB_DIR = Path("/app") / "storage" / "db"
+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)
+
+Base = declarative_base()
+
+# Dependency
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1,4 @@
+from app.models.item import Item
+from app.models.category import Category
+from app.models.supplier import Supplier
+from app.models.stock_movement import StockMovement, MovementType

app/models/category.py

@@ -0,0 +1,14 @@
+from sqlalchemy import Column, Integer, String, Boolean
+from sqlalchemy.sql import func
+from sqlalchemy.sql.sqltypes import TIMESTAMP
+from app.database import Base
+
+class Category(Base):
+    __tablename__ = "categories"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, nullable=False, unique=True)
+    description = Column(String, nullable=True)
+    is_active = Column(Boolean, default=True)
+    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now())
+    updated_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), onupdate=func.now())

app/models/item.py

@@ -0,0 +1,25 @@
+from sqlalchemy import Column, Integer, String, Float, Boolean, ForeignKey
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from sqlalchemy.sql.sqltypes import TIMESTAMP
+from app.database import Base
+
+class Item(Base):
+    __tablename__ = "items"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, nullable=False)
+    sku = Column(String, nullable=False, unique=True)
+    description = Column(String, nullable=True)
+    unit_price = Column(Float, nullable=False, default=0.0)
+    quantity = Column(Integer, nullable=False, default=0)
+    reorder_level = Column(Integer, nullable=False, default=0)
+    category_id = Column(Integer, ForeignKey("categories.id"), nullable=True)
+    supplier_id = Column(Integer, ForeignKey("suppliers.id"), nullable=True)
+    is_active = Column(Boolean, default=True)
+    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now())
+    updated_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), onupdate=func.now())
+    
+    # Relationships
+    category = relationship("Category", foreign_keys=[category_id])
+    supplier = relationship("Supplier", foreign_keys=[supplier_id])

app/models/stock_movement.py

@@ -0,0 +1,27 @@
+from sqlalchemy import Column, Integer, String, Float, ForeignKey, Enum
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from sqlalchemy.sql.sqltypes import TIMESTAMP
+import enum
+from app.database import Base
+
+class MovementType(str, enum.Enum):
+    PURCHASE = "purchase"
+    SALE = "sale"
+    ADJUSTMENT = "adjustment"
+    RETURN = "return"
+
+class StockMovement(Base):
+    __tablename__ = "stock_movements"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    item_id = Column(Integer, ForeignKey("items.id"), nullable=False)
+    quantity = Column(Integer, nullable=False)
+    movement_type = Column(Enum(MovementType), nullable=False)
+    reference = Column(String, nullable=True)
+    notes = Column(String, nullable=True)
+    unit_price = Column(Float, nullable=True)
+    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now())
+    
+    # Relationships
+    item = relationship("Item", foreign_keys=[item_id])

app/models/supplier.py

@@ -0,0 +1,17 @@
+from sqlalchemy import Column, Integer, String, Boolean
+from sqlalchemy.sql import func
+from sqlalchemy.sql.sqltypes import TIMESTAMP
+from app.database import Base
+
+class Supplier(Base):
+    __tablename__ = "suppliers"
+    
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, nullable=False, unique=True)
+    contact_name = Column(String, nullable=True)
+    email = Column(String, nullable=True)
+    phone = Column(String, nullable=True)
+    address = Column(String, nullable=True)
+    is_active = Column(Boolean, default=True)
+    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now())
+    updated_at = Column(TIMESTAMP(timezone=True), server_default=func.now(), onupdate=func.now())

app/routes/__init__.py

@@ -0,0 +1,5 @@
+from app.routes.item_routes import router as item_routes
+from app.routes.category_routes import router as category_routes
+from app.routes.supplier_routes import router as supplier_routes
+from app.routes.stock_routes import router as stock_routes
+from app.routes.health_routes import router as health_routes

app/routes/category_routes.py

@@ -0,0 +1,39 @@
+from fastapi import APIRouter, Depends, HTTPException, status, Query
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from app.database import get_db
+from app.schemas.category import CategoryCreate, CategoryUpdate, CategoryResponse
+from app.crud import category as category_crud
+
+router = APIRouter(
+    prefix="/categories",
+    tags=["Categories"]
+)
+
+@router.get("/", response_model=List[CategoryResponse])
+def get_categories(
+    skip: int = 0, 
+    limit: int = 100,
+    include_inactive: bool = False,
+    db: Session = Depends(get_db)
+):
+    return category_crud.get_categories(db, skip=skip, limit=limit, include_inactive=include_inactive)
+
+@router.get("/{category_id}", response_model=CategoryResponse)
+def get_category(category_id: int, db: Session = Depends(get_db)):
+    db_category = category_crud.get_category(db, category_id=category_id)
+    if db_category is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Category not found")
+    return db_category
+
+@router.post("/", response_model=CategoryResponse, status_code=status.HTTP_201_CREATED)
+def create_category(category: CategoryCreate, db: Session = Depends(get_db)):
+    return category_crud.create_category(db=db, category=category)
+
+@router.put("/{category_id}", response_model=CategoryResponse)
+def update_category(category_id: int, category: CategoryUpdate, db: Session = Depends(get_db)):
+    return category_crud.update_category(db=db, category_id=category_id, category=category)
+
+@router.delete("/{category_id}")
+def delete_category(category_id: int, db: Session = Depends(get_db)):
+    return category_crud.delete_category(db=db, category_id=category_id)

app/routes/health_routes.py

@@ -0,0 +1,17 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+from app.database import get_db
+
+router = APIRouter(
+    prefix="/health",
+    tags=["Health"]
+)
+
+@router.get("/")
+async def health_check(db: Session = Depends(get_db)):
+    try:
+        # Check if database is accessible
+        db.execute("SELECT 1")
+        return {"status": "healthy", "database": "connected"} 
+    except Exception as e:
+        return {"status": "unhealthy", "database": "disconnected", "error": str(e)}

app/routes/item_routes.py

@@ -0,0 +1,64 @@
+from fastapi import APIRouter, Depends, HTTPException, status, Query
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from app.database import get_db
+from app.schemas.item import ItemCreate, ItemUpdate, ItemResponse, ItemDetailResponse
+from app.crud import item as item_crud
+
+router = APIRouter(
+    prefix="/items",
+    tags=["Items"]
+)
+
+@router.get("/", response_model=List[ItemResponse])
+def get_items(
+    skip: int = 0, 
+    limit: int = 100,
+    category_id: Optional[int] = None,
+    supplier_id: Optional[int] = None,
+    include_inactive: bool = False,
+    db: Session = Depends(get_db)
+):
+    return item_crud.get_items(
+        db, 
+        skip=skip, 
+        limit=limit, 
+        category_id=category_id,
+        supplier_id=supplier_id,
+        include_inactive=include_inactive
+    )
+
+@router.get("/{item_id}", response_model=ItemDetailResponse)
+def get_item(item_id: int, db: Session = Depends(get_db)):
+    db_item = item_crud.get_item(db, item_id=item_id)
+    if db_item is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Item not found")
+    
+    # Convert related objects to dict for response
+    response = ItemDetailResponse.model_validate(db_item)
+    
+    if db_item.category:
+        response.category = {
+            "id": db_item.category.id,
+            "name": db_item.category.name
+        }
+    
+    if db_item.supplier:
+        response.supplier = {
+            "id": db_item.supplier.id,
+            "name": db_item.supplier.name
+        }
+    
+    return response
+
+@router.post("/", response_model=ItemResponse, status_code=status.HTTP_201_CREATED)
+def create_item(item: ItemCreate, db: Session = Depends(get_db)):
+    return item_crud.create_item(db=db, item=item)
+
+@router.put("/{item_id}", response_model=ItemResponse)
+def update_item(item_id: int, item: ItemUpdate, db: Session = Depends(get_db)):
+    return item_crud.update_item(db=db, item_id=item_id, item=item)
+
+@router.delete("/{item_id}")
+def delete_item(item_id: int, db: Session = Depends(get_db)):
+    return item_crud.delete_item(db=db, item_id=item_id)

app/routes/stock_routes.py

@@ -0,0 +1,54 @@
+from fastapi import APIRouter, Depends, HTTPException, status, Query
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from app.database import get_db
+from app.schemas.stock_movement import StockMovementCreate, StockMovementResponse, StockMovementDetailResponse
+from app.crud import stock_movement as stock_crud
+
+router = APIRouter(
+    prefix="/stock",
+    tags=["Stock Management"]
+)
+
+@router.get("/movements", response_model=List[StockMovementResponse])
+def get_stock_movements(
+    skip: int = 0, 
+    limit: int = 100,
+    item_id: Optional[int] = None,
+    db: Session = Depends(get_db)
+):
+    return stock_crud.get_stock_movements(db, skip=skip, limit=limit, item_id=item_id)
+
+@router.get("/movements/{movement_id}", response_model=StockMovementDetailResponse)
+def get_stock_movement(movement_id: int, db: Session = Depends(get_db)):
+    db_movement = stock_crud.get_stock_movement(db, movement_id=movement_id)
+    if db_movement is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Stock movement not found")
+    
+    # Convert related objects to dict for response
+    response = StockMovementDetailResponse.model_validate(db_movement)
+    
+    if db_movement.item:
+        response.item = {
+            "id": db_movement.item.id,
+            "name": db_movement.item.name,
+            "sku": db_movement.item.sku
+        }
+    
+    return response
+
+@router.post("/movements", response_model=StockMovementResponse, status_code=status.HTTP_201_CREATED)
+def create_stock_movement(movement: StockMovementCreate, db: Session = Depends(get_db)):
+    return stock_crud.create_stock_movement(db=db, movement=movement)
+
+@router.get("/low-stock", response_model=List[ItemResponse])
+def get_low_stock_items(db: Session = Depends(get_db)):
+    """Get items where quantity is less than or equal to reorder level"""
+    from app.models.item import Item
+    
+    low_stock_items = db.query(Item).filter(
+        Item.quantity <= Item.reorder_level,
+        Item.is_active == True
+    ).all()
+    
+    return low_stock_items

app/routes/supplier_routes.py

@@ -0,0 +1,39 @@
+from fastapi import APIRouter, Depends, HTTPException, status, Query
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from app.database import get_db
+from app.schemas.supplier import SupplierCreate, SupplierUpdate, SupplierResponse
+from app.crud import supplier as supplier_crud
+
+router = APIRouter(
+    prefix="/suppliers",
+    tags=["Suppliers"]
+)
+
+@router.get("/", response_model=List[SupplierResponse])
+def get_suppliers(
+    skip: int = 0, 
+    limit: int = 100,
+    include_inactive: bool = False,
+    db: Session = Depends(get_db)
+):
+    return supplier_crud.get_suppliers(db, skip=skip, limit=limit, include_inactive=include_inactive)
+
+@router.get("/{supplier_id}", response_model=SupplierResponse)
+def get_supplier(supplier_id: int, db: Session = Depends(get_db)):
+    db_supplier = supplier_crud.get_supplier(db, supplier_id=supplier_id)
+    if db_supplier is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Supplier not found")
+    return db_supplier
+
+@router.post("/", response_model=SupplierResponse, status_code=status.HTTP_201_CREATED)
+def create_supplier(supplier: SupplierCreate, db: Session = Depends(get_db)):
+    return supplier_crud.create_supplier(db=db, supplier=supplier)
+
+@router.put("/{supplier_id}", response_model=SupplierResponse)
+def update_supplier(supplier_id: int, supplier: SupplierUpdate, db: Session = Depends(get_db)):
+    return supplier_crud.update_supplier(db=db, supplier_id=supplier_id, supplier=supplier)
+
+@router.delete("/{supplier_id}")
+def delete_supplier(supplier_id: int, db: Session = Depends(get_db)):
+    return supplier_crud.delete_supplier(db=db, supplier_id=supplier_id)

app/schemas/__init__.py

@@ -0,0 +1,4 @@
+from app.schemas.item import ItemBase, ItemCreate, ItemUpdate, ItemResponse, ItemDetailResponse
+from app.schemas.category import CategoryBase, CategoryCreate, CategoryUpdate, CategoryResponse
+from app.schemas.supplier import SupplierBase, SupplierCreate, SupplierUpdate, SupplierResponse
+from app.schemas.stock_movement import StockMovementBase, StockMovementCreate, StockMovementResponse, StockMovementDetailResponse

app/schemas/category.py

@@ -0,0 +1,24 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+
+class CategoryBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+
+class CategoryCreate(CategoryBase):
+    pass
+
+class CategoryUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+    is_active: Optional[bool] = None
+
+class CategoryResponse(CategoryBase):
+    id: int
+    is_active: bool
+    created_at: datetime
+    updated_at: datetime
+    
+    class Config:
+        from_attributes = True

app/schemas/item.py

@@ -0,0 +1,38 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+
+class ItemBase(BaseModel):
+    name: str
+    sku: str
+    description: Optional[str] = None
+    unit_price: float
+    quantity: int = 0
+    reorder_level: int = 0
+    category_id: Optional[int] = None
+    supplier_id: Optional[int] = None
+
+class ItemCreate(ItemBase):
+    pass
+
+class ItemUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+    unit_price: Optional[float] = None
+    reorder_level: Optional[int] = None
+    category_id: Optional[int] = None
+    supplier_id: Optional[int] = None
+    is_active: Optional[bool] = None
+
+class ItemResponse(ItemBase):
+    id: int
+    is_active: bool
+    created_at: datetime
+    updated_at: datetime
+    
+    class Config:
+        from_attributes = True
+
+class ItemDetailResponse(ItemResponse):
+    category: Optional[dict] = None
+    supplier: Optional[dict] = None

app/schemas/stock_movement.py

@@ -0,0 +1,25 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+from app.models.stock_movement import MovementType
+
+class StockMovementBase(BaseModel):
+    item_id: int
+    quantity: int
+    movement_type: MovementType
+    reference: Optional[str] = None
+    notes: Optional[str] = None
+    unit_price: Optional[float] = None
+
+class StockMovementCreate(StockMovementBase):
+    pass
+
+class StockMovementResponse(StockMovementBase):
+    id: int
+    created_at: datetime
+    
+    class Config:
+        from_attributes = True
+
+class StockMovementDetailResponse(StockMovementResponse):
+    item: Optional[dict] = None

app/schemas/supplier.py

@@ -0,0 +1,30 @@
+from pydantic import BaseModel, EmailStr
+from typing import Optional
+from datetime import datetime
+
+class SupplierBase(BaseModel):
+    name: str
+    contact_name: Optional[str] = None
+    email: Optional[EmailStr] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+
+class SupplierCreate(SupplierBase):
+    pass
+
+class SupplierUpdate(BaseModel):
+    name: Optional[str] = None
+    contact_name: Optional[str] = None
+    email: Optional[EmailStr] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+    is_active: Optional[bool] = None
+
+class SupplierResponse(SupplierBase):
+    id: int
+    is_active: bool
+    created_at: datetime
+    updated_at: datetime
+    
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,30 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from app.routes import item_routes, category_routes, supplier_routes, stock_routes, health_routes
+from app.database import engine, Base
+
+app = FastAPI(
+    title="Small Business Inventory Management System",
+    description="API for managing inventory for small businesses",
+    version="1.0.0"
+)
+
+# Add CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(health_routes.router)
+app.include_router(item_routes.router)
+app.include_router(category_routes.router)
+app.include_router(supplier_routes.router)
+app.include_router(stock_routes.router)
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,8 @@
+fastapi==0.110.0
+uvicorn==0.28.0
+sqlalchemy==2.0.29
+alembic==1.13.1
+pydantic==2.6.1
+python-dotenv==1.0.1
+python-multipart==0.0.9
+email-validator==2.1.0