Implement roommate management application with expense splitting and auto-task assignment

[Copilot]

Built a full-stack web application for managing shared living expenses and household tasks with automatic fair distribution among roommates.

Core Implementation

Expense Management

• Equal and custom percentage-based splitting with optimized settlement algorithm (minimizes transaction count)
• Real-time balance calculations across all expenses
• Per-user settlement tracking

Task Auto-Assignment

• Fair rotation algorithm with deterministic tie-breaking via assignment history
• Recurring tasks (daily/weekly/monthly) with automatic reassignment on completion
• Edge case handling for month-end date calculations

Example: Settlement Algorithm

// Calculates minimum transactions to settle all debts
function calculateBalances(expenses, members) {
  const balances = {};
  
  expenses.forEach(expense => {
    balances[expense.paidBy] += expense.amount;
    expense.splitBetween.forEach(split => {
      if (!split.settled) balances[split.user] -= split.amount;
    });
  });
  
  // Greedy matching of debtors to creditors
  const settlements = [];
  // ... returns optimized settlement plan
}

Technical Stack

Backend (Node.js/Express/MongoDB)

• JWT authentication with bcrypt (12 rounds)
• Three-tier rate limiting: auth (5/15min), create (30/15min), general (100/15min)
• Mongoose models: User, Room, Expense, Task

Frontend (React 18)

• Single-page application with React Router v6
• Responsive design with mobile-first approach
• Tabbed room interface (Overview, Expenses, Tasks, Members)

Security

• 0 CodeQL vulnerabilities
• Environment validation (fails on production startup if JWT_SECRET unset)
• Rate limiting applied before authentication middleware
• Protected routes with bearer token auth

API Surface

POST   /api/users/register, /api/users/login
GET    /api/rooms, /api/expenses/room/:id/balances, /api/tasks/my-tasks
POST   /api/rooms, /api/expenses, /api/tasks
PUT    /api/expenses/:id/settle/:userId, /api/tasks/:id/status
DELETE /api/expenses/:id, /api/tasks/:id

Multi-room support via 8-character invite codes. Room admins can manage members; all members can add expenses/tasks.

Original prompt

this is website of my application that is roommate management application that help in split and manage expanse between roommates & help in auto assign daily tasks between all members also give more attractive and helpfull feature that make roommates life ease

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