.cursorrules (deprecated)

1You are an expert in **Python, FastAPI, scalable API development, TypeScript, React, Tailwind,** and **Shadcn UI**.### Key Principles- Write concise, technical responses with accurate examples in both Python and TypeScript.- Use **functional and declarative programming patterns**; avoid classes unless absolutely necessary.- Prefer **iteration and modularization** over code duplication.- Use descriptive variable names with auxiliary verbs (e.g., `is_active`, `has_permission`, `isLoading`, `hasError`).- Follow proper **naming conventions**:  - For Python: use lowercase with underscores (e.g., `routers/user_routes.py`). - For TypeScript: use lowercase with dashes for directories (e.g., `components/auth-wizard`).### Project Structure- **Frontend**: - **Language**: TypeScript - **Framework**: React - **UI Library**: Tailwind CSS, Shadcn UI - **Build Tool**: Vite - **Directory Structure**:  - `frontend/src/`: Main source code  - `frontend/src/index.html`: Main HTML file  - Configuration Files:   - `vite.config.ts`   - `tsconfig.json`   - `tailwind.config.js`   - `postcss.config.js`  - **Docker Files**:   - `Dockerfile`   - `Dockerfile.dev`- **Backend**: - **Language**: Python - **Framework**: FastAPI - **Database**: PostgreSQL - **Directory Structure**:  - `backend/src/`: Main source code  - `backend/tests/`: Tests  - `document-processor/`: Document processing utilities  - Environment Configuration:   - `.env` / `.env.example`: Environment variables  - Database Configuration:   - `alembic.ini`   - `ddialog.db`: SQLite database for local development  - **Docker Files**:   - `Dockerfile`   - `Dockerfile.dev`### Code Style and Structure**Backend (Python/FastAPI)**:- Use `def` for pure functions and `async def` for asynchronous operations.- **Type Hints**: Use Python type hints for all function signatures. Prefer Pydantic models for input validation.- **File Structure**: Follow clear separation with directories for routes, utilities, static content, and models/schemas.- **RORO Pattern**: Use the "Receive an Object, Return an Object" pattern.- **Error Handling**: - Handle errors at the beginning of functions with early returns. - Use guard clauses and avoid deeply nested if statements. - Implement proper logging and custom error types.**Frontend (TypeScript/React)**:- **TypeScript Usage**: Use TypeScript for all code. Prefer interfaces over types. Avoid enums; use maps instead.- **Functional Components**: Write all components as functional components with proper TypeScript interfaces.- **UI and Styling**: Implement responsive design using Tailwind CSS with Shadcn UI, adopting a mobile-first approach.- **Performance**: - Minimize `use client`, `useEffect`, and `setState` hooks. Favor server-side rendering where possible. - Wrap client components in `Suspense` with fallback for improved performance.### Performance Optimization**Backend**:- **Asynchronous Operations**: Minimize blocking I/O operations using async functions.- **Caching**: Implement caching strategies for frequently accessed data using Redis or in-memory stores.- **Lazy Loading**: Use lazy loading techniques for large datasets and API responses.**Frontend**:- **React Components**: Favor server-side rendering and avoid heavy client-side rendering where possible.- **Dynamic Loading**: Implement dynamic loading for non-critical components and optimize image loading using WebP format with lazy loading.### Project Conventions**Backend**:1. Follow **RESTful API design principles**.2. Rely on **FastAPI’s dependency injection system** for managing state and shared resources.3. Use **SQLAlchemy 2.0** for ORM features, if applicable.4. Ensure **CORS** is properly configured for local development.5. No authentication or authorization is required for users to access the platform.**Frontend**:1. Optimize **Web Vitals** (LCP, CLS, FID).2. Limit `use client` hooks to small, specific components for Web API access.3. Use **Docker** for containerization and ensure easy deployment.### Testing and Deployment- Implement **unit tests** for both frontend and backend.- Use **Docker** and **docker compose** for orchestration in both development and production environments. Avoid using the obsolete `docker-compose` command.- Ensure proper input validation, sanitization, and error handling throughout the application.