🏠 Shared Expense System

The cleanest way to track shared expenses with your roommates.
Split bills, settle debts, and live in peace — with full Nepali Rupee (NPR) & Bikram Sambat (BS) support.

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✨ Features

Feature	Description
🔐 Authentication	Email/password & Google OAuth via Supabase Auth
🏘️ Multiple Rooms	Create or join multiple rooms — manage different groups of friends
💸 Expense Splitting	Add shared or personal expenses, split equally among members
⚖️ Balance Tracking	Automatically calculates who owes whom
✅ Settle Up	Mark debts as paid with one click
🇳🇵 NPR / BS Support	Display amounts in Nepali Rupees and dates in Bikram Sambat — switchable per session
📋 Activity Logs	Full history of all expenses and settlements
🔗 Invite Codes	Share a unique code to invite roommates to your room
⚡ Real-time	Supabase Realtime enabled for expenses and settlements

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🛠️ Tech Stack

• Framework: Next.js 16 (App Router, Server Actions)
• Backend / Database: Supabase (PostgreSQL + Auth + Realtime)
• Styling: Tailwind CSS v4 + shadcn/ui
• Language: TypeScript
• Nepali Date: @sbmdkl/nepali-date-converter

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🚀 Getting Started

Prerequisites

• Node.js v18+
• A Supabase project (free tier works fine)

1. Clone the repository

git clone https://github.com/Susant07-star/Shared_Expense_System.git
cd Shared_Expense_System/roommate-expense-app

2. Install dependencies

npm install

3. Set up environment variables

Create a .env.local file in the project root:

NEXT_PUBLIC_SUPABASE_URL=your_supabase_project_url
NEXT_PUBLIC_SUPABASE_ANON_KEY=your_supabase_anon_key

You can find these in your Supabase project under Settings → API.

4. Set up the database

Copy the SQL from supabase_schema.sql and run it in your Supabase project's SQL Editor.

This sets up:

• All tables (users, rooms, room_members, expenses, expense_splits, settlements, activity_logs)
• Row Level Security (RLS) policies
• Triggers for auto-creating user profiles
• RPC functions for invite code lookup
• Realtime publication

5. (Optional) Enable Google OAuth

In your Supabase dashboard → Authentication → Providers → Google, enable Google and add your OAuth credentials. Set the callback URL to:

https://your-project.supabase.co/auth/v1/callback

6. Run the development server

npm run dev

Open http://localhost:3000 in your browser.

7. Validate a production build

Run the checks from the app directory before deploying:

npm run lint
npm run build

The app uses local system font fallbacks rather than fetching fonts from Google during a build. This keeps builds reproducible and avoids delaying the first render when external font requests are unavailable.

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📁 Project Structure

src/
├── app/
│   ├── (auth)/            # Login & Signup pages + server actions
│   │   ├── login/
│   │   └── signup/
│   ├── auth/callback/     # OAuth callback handler
│   └── dashboard/         # Protected dashboard pages
│       ├── activity/      # Activity log
│       ├── expenses/      # Full expense history
│       ├── members/       # Room members list
│       └── settings/      # Room settings
├── components/
│   ├── dashboard-view.tsx # Main dashboard UI (client component)
│   └── shared/
│       └── dashboard-nav.tsx  # Sidebar with room switcher
└── lib/
    ├── balances.ts        # Balance calculation logic
    ├── nepali.ts          # NPR/BS date & currency formatting
    └── supabase/          # Supabase client helpers

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🗃️ Database Schema

auth.users (Supabase)
    │
    ▼
public.users ──────────── public.room_members ──── public.rooms
                                 │
                    ┌────────────┴────────────┐
                    ▼                         ▼
            public.expenses          public.settlements
                    │
                    ▼
          public.expense_splits

public.activity_logs (linked to rooms + users)

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🇳🇵 Nepali Support

This app supports Nepali Rupees (NPR) and Bikram Sambat (BS) dates as the primary display format.

• All amounts are stored internally in USD and converted on display
• All dates are stored in UTC and converted to BS using @sbmdkl/nepali-date-converter — no hardcoded calendar tables
• Users can switch between NPR/BS and USD/AD via the currency dropdown in the dashboard

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🔒 Security

• All database tables have Row Level Security (RLS) enabled
• Users can only read/write data for rooms they are members of
• .env.local is excluded from version control via .gitignore
• Auth tokens are managed securely via Supabase SSR cookies

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📜 License

This project is open source under the MIT License.

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Built with ❤️ using Next.js and Supabase