FastCheck/FastCheck/IMPLEMENTATION.md

FastCheck Application - Implementation Summary

✅ Completed Features

1. Project Structure

• ✅ Angular 21 standalone components architecture
• ✅ TypeScript models for type safety
• ✅ SCSS styling with modern design
• ✅ Modular service-based architecture

2. Authentication System

• ✅ QR Code login component
• ✅ WebSession management
• ✅ Auto-polling every 2 seconds to check login status
• ✅ Session persistence in sessionStorage
• ✅ Route guards for protected pages

3. Dashboard

• ✅ Balance display (mocked)
• ✅ Create FastCheck with custom amount
• ✅ Accept FastCheck with number (xxxx-xxxx-xxxx) and code (xxxx)
• ✅ FastCheck number auto-formatting
• ✅ Success/error handling
• ✅ Modal to display created check details

4. Active Checks Page

• ✅ List all unused FastChecks
• ✅ Copy to clipboard functionality
• ✅ Display check details (number, code, amount, expiration)
• ✅ Security warnings

5. Transaction History

• ✅ View all used/expired checks
• ✅ Distinguish between created and accepted checks
• ✅ Timestamps and status display

📁 File Structure

FastCheck/
├── public/
│   ├── api.txt                    # Original API documentation
│   └── missing-apis.txt           # Missing API specifications for backend
├── src/
│   ├── app/
│   │   ├── components/
│   │   │   ├── login/             # QR login with polling
│   │   │   ├── dashboard/         # Main dashboard
│   │   │   ├── active-checks/     # Active checks list
│   │   │   └── history/           # Transaction history
│   │   ├── services/
│   │   │   ├── api.service.ts     # HTTP client wrapper
│   │   │   ├── auth.service.ts    # Authentication & session management
│   │   │   └── fastcheck.service.ts # FastCheck operations
│   │   ├── models/
│   │   │   ├── session.model.ts   # Session interfaces
│   │   │   ├── fastcheck.model.ts # FastCheck interfaces
│   │   │   └── api.model.ts       # API response interfaces
│   │   ├── guards/
│   │   │   └── auth.guard.ts      # Route protection
│   │   ├── app.routes.ts          # Route configuration
│   │   ├── app.config.ts          # App configuration
│   │   ├── app.ts                 # Root component
│   │   ├── app.html               # Root template
│   │   └── app.scss               # Global styles
│   ├── environments/
│   │   └── environment.ts         # Environment configuration
│   ├── index.html                 # Main HTML
│   ├── main.ts                    # Bootstrap
│   └── styles.scss                # Global styles
├── package.json
└── README.md                      # Project documentation

🔧 Technologies Used

• Angular 21 - Modern standalone components
• TypeScript - Type-safe development
• RxJS - Reactive programming (polling, API calls)
• SCSS - Styling
• angularx-qrcode - QR code generation
• HttpClient - API communication

🎨 Design Features

• Modern gradient UI (purple/violet theme)
• Responsive layout
• Smooth animations and transitions
• Loading states and spinners
• Error handling with user-friendly messages
• Copy-to-clipboard functionality
• Modal dialogs for important information

🔌 API Integration

Fully Integrated:

1. GET /ping - Server health check
2. GET /websession - Create login session
3. GET /websession/:id - Poll login status
4. DELETE /websession/:id - Logout
5. POST /fastcheck - Create new check (with Authorization)
6. POST /fastcheck - Accept check (with Authorization)
7. GET /fastcheck - Check status

Mocked (Need Backend Implementation):

1. GET /balance - Get user balance
2. GET /fastcheck/active - List active checks
3. GET /fastcheck/history - Transaction history

See public/missing-apis.txt for complete API specifications.

🚀 Running the Application

# Navigate to project directory
cd F:\dx\remote\FastCheck\FastCheck

# Install dependencies (already done)
npm install

# Start development server
npm start

# Open browser at http://localhost:4200

📝 Next Steps for Backend Team

1. Implement Missing APIs:

   • Balance endpoint
   • Active checks endpoint
   • History endpoint

2. Bank Integration:

   • Payment gateway API
   • Redirect URLs for payment flow
   • Webhook for payment confirmation
   • Balance top-up mechanism

3. Update Frontend When Ready:

   • Uncomment real API calls in fastcheck.service.ts
   • Remove mock of() observables
   • Test with real data

🔐 Security Considerations

• SessionID stored in sessionStorage (clears on tab close)
• Authorization header on all authenticated requests
• CORS must be configured on backend
• HTTPS required in production
• FastCheck codes are sensitive - handle securely

📱 User Flow

1. Login:

   • User opens app → sees QR code
   • Scans with mobile app
   • Frontend polls every 2s
   • Redirects to dashboard on success

2. Create FastCheck:

   • Enter amount
   • Click create
   • Get number + code in modal
   • Save credentials securely

3. Accept FastCheck:

   • Enter number (auto-formatted)
   • Enter code
   • Submit
   • Money added to balance

4. View Checks:

   • Active checks → unused checks with copy feature
   • History → all used/expired transactions

🐛 Known Limitations (Temporary)

• Balance API is mocked (returns 150,000 RUB)
• Active checks are mocked (returns 2 sample checks)
• History is mocked (returns 2 sample transactions)
• Bank integration not implemented yet
• No actual QR scanning (need mobile app integration)

📞 Contact

Developer: sdarbinyan@4pay.ru Project: FastCheck СБП Payment System Company: 4Pay

✨ Status

Development Server: ✅ Running on http://localhost:4200 All Components: ✅ Implemented Routing: ✅ Configured with guards Styling: ✅ Complete with modern UI Mock Data: ✅ In place for testing Documentation: ✅ Complete

Ready for backend integration and testing!