frontend_requirements.md

# Frontend Requirements

## Overview
This document outlines the technical requirements for the React frontend of the Lin application.

## Core Technologies
- React 18+
- React Router v6+
- Redux Toolkit for state management
- Axios for HTTP requests
- Material-UI (MUI) for UI components
- Formik for form handling
- Yup for form validation

## Development Tools
- Node.js 16+
- npm or yarn package manager
- Create React App or Vite for project setup
- ESLint for code linting
- Prettier for code formatting
- Jest and React Testing Library for testing

## Package Dependencies

### Core Dependencies
```json
{
  "@mui/material": "^5.0.0",
  "@mui/icons-material": "^5.0.0",
  "@reduxjs/toolkit": "^1.8.0",
  "axios": "^0.27.0",
  "formik": "^2.2.9",
  "react": "^18.0.0",
  "react-dom": "^18.0.0",
  "react-redux": "^8.0.0",
  "react-router-dom": "^6.3.0",
  "yup": "^0.32.11"
}
```

### Development Dependencies
```json
{
  "@testing-library/jest-dom": "^5.16.4",
  "@testing-library/react": "^13.3.0",
  "@testing-library/user-event": "^14.2.0",
  "eslint": "^8.18.0",
  "prettier": "^2.7.1",
  "jest": "^28.1.1"
}
```

## Browser Support
- Latest versions of Chrome, Firefox, Safari, and Edge
- Mobile browsers (iOS Safari, Chrome for Android)
- Responsive design for all screen sizes

## UI/UX Requirements

### Design System
- Consistent color palette based on brand colors
- Typography hierarchy with appropriate font sizes
- Spacing system using consistent units
- Component library with reusable UI elements

### Responsive Design
- Mobile-first approach
- Flexible grid system
- Adaptive components for different screen sizes
- Touch-friendly interface elements

### Accessibility
- WCAG 2.1 AA compliance
- Proper semantic HTML
- Keyboard navigation support
- Screen reader compatibility
- Color contrast ratios meeting accessibility standards

## State Management

### Redux Store Structure
```javascript
{
  auth: {
    user: object,
    isAuthenticated: boolean,
    loading: boolean,
    error: string
  },
  sources: {
    items: array,
    loading: boolean,
    error: string
  },
  posts: {
    items: array,
    loading: boolean,
    error: string
  },
  accounts: {
    items: array,
    loading: boolean,
    error: string
  },
  schedules: {
    items: array,
    loading: boolean,
    error: string
  }
}
```

### Actions and Reducers
- Async thunks for API calls
- Error handling in reducers
- Loading states for async operations
- Normalized data structure for efficient lookups

## Routing

### Routes Structure
- `/` - Dashboard (protected)
- `/login` - Login page (public)
- `/register` - Registration page (public)
- `/sources` - Source management (protected)
- `/posts` - Post management (protected)
- `/schedule` - Scheduling (protected)
- `/*` - 404 page

### Route Protection
- Authentication guard for protected routes
- Redirect logic for authenticated users
- Loading states during authentication checks

## API Integration

### Service Layer
- Axios instance with base URL configuration
- Request and response interceptors
- Error handling and transformation
- Authentication token management

### API Error Handling
- Network error detection
- HTTP error status handling
- User-friendly error messages
- Retry mechanism for failed requests

## Form Handling

### Form Libraries
- Formik for form state management
- Yup for form validation
- Custom validation rules
- Async validation support

### Form Components
- Reusable input components
- Validation error display
- Loading states during submission
- Success feedback after submission

## Testing Requirements

### Unit Tests
- Component rendering tests
- Redux action and reducer tests
- Utility function tests
- Hook tests

### Integration Tests
- Form submission flows
- API integration tests
- Routing tests
- Authentication flow tests

### Test Coverage
- Minimum 80% code coverage
- Testing of edge cases
- Mocking of external dependencies
- Continuous integration setup

## Performance Requirements

### Loading States
- Skeleton loaders for data fetching
- Progress indicators for long operations
- Optimistic updates where appropriate
- Error boundaries for component failures

### Bundle Optimization
- Code splitting for route-based chunks
- Lazy loading for non-critical components
- Image optimization and lazy loading
- Minification and compression

### Caching Strategy
- HTTP caching headers
- Client-side caching for static data
- Cache invalidation strategies
- Service worker implementation (optional)

## Security Considerations

### Client-Side Security
- XSS prevention through proper data escaping
- CSRF protection for forms
- Secure storage of authentication tokens
- Input validation and sanitization

### Authentication
- Secure token storage (HttpOnly cookies or secure localStorage)
- Token expiration and refresh mechanisms
- Logout functionality
- Session management

## Deployment Requirements

### Build Process
- Production build optimization
- Environment-specific configuration
- Asset fingerprinting for cache busting
- Source map generation for debugging

### Hosting
- Static file hosting (Netlify, Vercel, or similar)
- CDN integration for asset delivery
- SSL certificate for HTTPS
- Custom domain support

### CI/CD
- Automated testing on pull requests
- Automated deployment on merge to main branch
- Environment-specific deployments
- Rollback capabilities