🎮 Guess Two‑Thirds Game (Web3 dApp on Base)

This project is a decentralized version of the classic “Guess 2 / 3 of the Average” game‑theory experiment.
Players participate on‑chain by sending ETH on Base; the contribution that lands closest to 2 / 3 of the average wins the prize pool (minus a 1 % fee).

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🌐 Live App

Play it here:

https://guessavg.github.io/game/   

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📦 Features

• MetaMask (or any EIP‑1193 wallet) connect
• One‑click add / switch to Base network
• Join a round by sending any amount of ETH
• Real‑time UI showing
  • Current round ID
  • Player list & stakes
  • Contract balance
  • Last winner & reward
• Built with ethers.js v6

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⚙️ How It Works

1. Users send ETH to the contract’s play() function.
2. A pseudo‑random stop‑condition (parametrised at deployment) decides when the round ends.
3. The stake closest to 2 / 3 × average wins; ties are broken by earliest entry.
4. Winner receives the pool minus a 1 % fee to the owner.
5. Front‑end polls on‑chain data and past GameEnded events for live updates.

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🔧 Smart Contract Info

Item	Value
Contract address	0x4BbeE9F876ff56832E724DC9a7bD06538C8868D2
Network RPC	https://base-rpc.publicnode.com
Chain ID	8453 (0x2105)
Block explorer	https://basescan.org

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🧪 Tech Stack

• Vanilla HTML / JavaScript
• ethers.js v6
• MetaMask (EIP‑1193 provider)
• Static hosting (e.g. GitHub Pages)

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📄 Contract ABI (used in front‑end)

[
  "function gameId() view returns (uint256)",
  "function players(uint256) view returns (address addr, uint256 amount)",
  "function play() payable",
  "function hasPlayed(address) view returns (bool)",
  "event PlayerJoined(address indexed player, uint256 amount)",
  "event GameEnded(uint256 indexed gameId, address winner, uint256 reward, uint256 guessTarget)"
]

🚀 Run Locally

To test this dApp locally, use any HTTP server:

# Python 3
python -m http.server

Then visit http://localhost:8000 in your browser.

⚠️ Opening file:// URLs directly will cause MetaMask injection to fail. Always use a local server.

🛠️ Troubleshooting

• "MetaMask not detected" → Ensure MetaMask is installed and page is served over HTTP/HTTPS.
• "Failed to add Oiia Network" → Try upgrading MetaMask, or ensure you're not using a mobile browser.
• Wallet not connecting → Check browser extension permissions for GitHub Pages.

📜 License

MIT License.