💸 PayUp – Group Expense & Payment Tracker

PayUp is a web-based Server-side Java application designed to simplify group expense management. It enables users to log expenses, send or receive payment requests, and track outstanding payments. The project is built with Javalin as the web framework and Thymeleaf for server-side HTML templating.

---

📦 Tech Stack

• Language: Java 17+
• Framework: Javalin
• Template Engine: Thymeleaf
• Build Tool: Maven
• Currency Handling: JavaMoney (Moneta)
• Session Handling: Jetty
• Validation: Apache Commons & Guava
• Persistence: In-memory DAO pattern

---

🚀 Features

• 👥 User login via email (mock authentication)
• 📋 Record and view personal expenses
• 🧾 Request payments from others
• ✅ Accept and process payment requests
• 💰 See outstanding amounts owed to/from users
• 📊 Visual HTML interface using Thymeleaf
• 🧪 In-memory data seed for demo/testing

---

🗂️ Project Structure

src/
├── main/
│   ├── java/
│   │   └── payup/
│   │       ├── controller/         # Web controllers (Javalin Handlers)
│   │       ├── model/              # Expense, PaymentRequest, Person, MoneyHelpers
│   │       ├── persistence/        # DAO interfaces and in-memory implementations
│   │       └── server/             # App server, routes, and service registry
│   └── resources/
│       ├── templates/              # Thymeleaf HTML templates
│       └── html/                   # Static resources (index.html, CSS)
├── test/                           # Unit/integration tests (if added)

---

▶️ Running the Application

💻 Via Maven

1. Clone the repository:

   git clone https://github.com/thembaxaba157/payup.git
   cd payup

2. Build and run:

   mvn clean package
   java -cp target/payup-1.0-SNAPSHOT.jar payup.server.PayUpServer

3. Open in your browser:

   http://localhost:5050/
   

---

👤 Login Info

Use any valid email (e.g. alice@example.com) to simulate a login. No password required. Demo data will auto-load.

---

🌐 Available Routes

Route	Purpose
/	Login page
/login.action	Login handler
/expenses	View expenses
/newexpense	Add new expense
/expense.action	Submit new expense
/paymentrequest	View payment requests for an expense
/paymentrequest.action	Create new payment request
/paymentrequests_sent	See who owes you
/paymentrequests_received	See who you owe
/payment.action	Submit payment
/logout	Logout

---

📷 UI Overview

• Login Page: Email entry with session tracking
• Expenses: Table showing expenses, payments requested/received
• Payment Requests: List per expense or person
• Styles: Basic responsive layout with Google Fonts and Normalize.css
• Templates: Modular Thymeleaf layout for shared HTML sections

---

🧪 Demo Seed Data (Auto-Loaded)

Upon server start, the app seeds:

• 3 users (student1@mockemail.com, student2@mockemail.com, student3@mockemail.com)
• Sample expenses
• Linked payment requests

This allows you to immediately explore the app.

---

⚠️ Limitations & Notes

• No real authentication (demo only)
• No persistent storage — memory resets on restart
• No JavaScript — pure HTML/CSS/Thymeleaf

---

📜 License

MIT License – free to use, modify, and distribute.

---

👨‍💻 Author

Built by [Your Name]. Contributions welcome!