System DApp Voting

🚀 A decentralized voting application composed of three services:

1. Smart Contracts (Solidity & Foundry)
2. Frontend (Next.js + Wagmi + RainbowKit)
3. Oracle Service (Express.js)

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📦 Repository Structure

system-dapp-voting/
├── contract-dapp-voting           # Solidity smart contracts (submodule)
│   └── ...
├── fe-dapp-voting/                # Next.js frontend application (submodule)
│   └── ...
├── oracle-dapp-voting/            # Oracle client (submodule)
│   └── ...
└── README.md           # (this file)

Note: The contract-dapp-voting/, fe-dapp-voting/, and oracle-dapp-voting/ folder is a Git submodule.

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🔗 Getting Started

1. Clone the repository

git clone https://github.com/Lev1reG/system-dapp-voting.git
cd system-dapp-voting

2. Update submodules

The Oracle service is included as a submodule. After cloning, initialize and update:

git submodule init
git submodule update --init --recursive

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🧩 Architecture Overview

Below is a high-level diagram of how the three services interact:

1. Smart Contracts

   • Deploy on a testnet (Sepolia).
   • Emit events: VotingSessionCreated, CandidateRegistered, Voted.

2. Oracle Service (Express.js)

   • Listens to on-chain events.
   • For VotingSessionCreated: fetch HR data → determine eligible voters.
   • For CandidateRegistered: save new candidate data to backend.

3. Frontend (Next.js)

   • Connects Wallet (RainbowKit + Wagmi).
   • Displays available sessions, candidates, vote counts.
   • Calls vote(sessionId, candidateAddr) on-chain.

4. Backend (Next.js API)

   • Stores off-chain data if needed (e.g., voter eligibility).

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🗳️ Voting Flow

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⚙️ Quick Setup

1. Smart Contracts (Foundry)

1. Install Foundry & dependencies:

   cd contract-dapp-voting
   forge install OpenZeppelin/openzeppelin-contracts
   forge build

2. Deploy to a testnet:

   forge script script/DeployVoting.s.sol --rpc-url $RPC_URL --private-key $PRIVATE_KEY --broadcast

3. Note the deployed contract address → set NEXT_PUBLIC_CONTRACT_ADDRESS in frontend.

2. Frontend (Next.js)

1. Move to fe-dapp-voting/:

   cd ../fe-dapp-voting
   npm install

2. Create .env:

   NEXT_PUBLIC_CONTRACT_ADDRESS=0xYourContractAddress
   

3. Start dev server:

   npm run dev

3. Oracle Service

1. Initialize submodule if not done:

   cd ../oracle-dapp-voting
   git submodule init
   git submodule update --init --recursive

2. Install dependencies:

   npm install

3. Create .env:

   RPC_URL=https://sepolia.infura.io/v3/[ID]
   PRIVATE_KEY=0xYOUR_ADMIN_PRIVATE_KEY
   CONTRACT_ADDRESS=0xYourContractAddress
   BACKEND_URL=http://localhost:3000
   

4. Run Oracle:

   npm run dev

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👥 Developers

• Benaya Imanuela (Student ID: 22/494790/TK/54313)
• Deren Tanaphan (Student ID: 22/503261/TK/54976)

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