GitHub Copilot - Inventory System

This skill provides context and actionable instructions for working with an inventory management system built with FastAPI (backend) and React + Vite (frontend).

System Architecture

The application consists of:

- Entry point: `backend/main.py`

- Database: `backend/inventory.db` (SQLite)

- Location: `frontend/frontend/`

- Dev server: runs on port 5173

- API client: `frontend/frontend/src/api.js`

- Product → Dimension → SliderType/Color → Stock

- Defined in `backend/models.py`

Running the Application

Backend Setup

Start the FastAPI server from the repository root:

```bash

cd backend && uvicorn main:app --reload --port 8000

```

Or from root directory:

```bash

uvicorn backend.main:app --reload --port 8000

```

Database Seeding

Create and populate the database:

```bash

python backend/seed.py

```

This creates `backend/inventory.db` with seed data.

Frontend Setup

Start the Vite dev server:

```bash

cd frontend/frontend && npm install && npm run dev

```

The frontend will be available at `http://localhost:5173`.

CORS Configuration

Key Files Reference

When making changes, consult these files based on the component:

| Component | File | Purpose |

|-----------|------|---------|

| API routing | `backend/main.py` | FastAPI endpoint definitions |

| Business logic | `backend/crud.py` | Database operations and transactions |

| Database models | `backend/models.py` | SQLAlchemy ORM models |

| API schemas | `backend/schemas.py` | Pydantic v2 request/response models |

| Pricing/sizing | `backend/utils.py` | Pure utility functions |

| Database config | `backend/database.py` | SQLAlchemy setup |

| Seed data | `backend/seed.py` | Initial database population |

| Frontend API | `frontend/frontend/src/api.js` | HTTP client functions |

| Frontend components | `frontend/frontend/src/` | React components |

Code Patterns and Conventions

Pydantic v2

All Pydantic models use v2 syntax:

```python

class Config:

from_attributes = True

```

CRUD Pattern

Size Rules

Size handling uses `SizeRule` model:

Pricing Logic

Pricing is centralized in pure functions:

```python

utils.compute_price(base_price, size, base_size)

```

Error Handling

Known Issues and Gotchas

1. **SQLite Path**: Database URL is `sqlite:///./inventory.db` (relative path)

- Run commands from `backend/` directory

- Or adjust path in `backend/database.py`

2. **Code Duplication**: Some endpoints and `get_db()` function appear twice in `backend/main.py`

- Be conservative with cleanup

- Document any refactoring in pull requests

3. **Dependencies**: No `requirements.txt` exists

- Minimum backend dependencies: `fastapi`, `uvicorn`, `sqlalchemy`, `pydantic`

- Frontend: run `npm install` in `frontend/frontend/`

4. **No Test Suite**: Currently no automated tests

- Document test plans in pull requests

- Add unit tests for `backend/utils.py` functions when modifying

Common Tasks

Adding a New API Endpoint

1. Add database logic to `backend/crud.py`

2. Define Pydantic schema in `backend/schemas.py` (if needed)

3. Create endpoint in `backend/main.py` with appropriate `response_model`

4. Add frontend API call to `frontend/frontend/src/api.js` (if needed)

Example:

```python

In backend/crud.py

def get_product_names(db: Session):

return db.query(models.Product.name).all()

In backend/main.py

@app.get("/products/names", response_model=list[schemas.ProductBase])

def list_product_names(db: Session = Depends(get_db)):

return crud.get_product_names(db)

```

Modifying Pricing Logic

1. Edit `backend/utils.py::compute_price()`

2. Keep function pure (no side effects)

3. Add unit tests (create test file if needed)

4. Document changes in pull request

Changing Data Model

1. Update SQLAlchemy models in `backend/models.py`

2. Update corresponding Pydantic schemas in `backend/schemas.py`

3. Create migration plan (manual migration required)

4. Update seed data in `backend/seed.py` if needed

5. Document migration steps in pull request

Frontend Changes

1. Modify React components in `frontend/frontend/src/`

2. Update API client in `frontend/frontend/src/api.js` if endpoints change

3. Test with dev server on port 5173

Pull Request Guidelines

- Database logic → `crud.py`

- Pure functions → `utils.py`

- Routing only → `main.py`

- Include clear migration/seed plan when changing models

- Document any required manual steps

- Describe test plan in PR description

- Consider adding unit tests for new utility functions

Working Directory Context

Most commands assume execution from specific directories:

If encountering path issues, confirm intended working directory before modifying configuration files.