SceneMood Chain

Required keys.

Add these in your Lovable project under Settings → Secrets before pasting the prompt below.

Paste into a fresh Lovable project. Make sure all five secrets above are set first. read the build strategy →

Build "SceneMood Chain" in ONE Lovable message. Single-page demo.

CONCEPT
Record color grading versions on blockchain to secure post-production creative decisions.
Discipline: Filmmaking & Animation (color grading proof).
Onchain primitive: Sepolia smart contract. Why this primitive: Sepolia contracts timestamp and preserve immutable color study records.

5-CREDIT BUDGET (HARD LIMIT):
- ONE single-page app. No router, no Lovable Cloud, no database, no auth flows beyond Privy drop-in.
- ONE Solidity contract, <=80 lines, deployed to Sepolia, verified on Etherscan.
- Privy is always the auth + sponsored-tx layer (Google login, embedded wallet).
- Pinata/IPFS only if the idea genuinely needs to store a file or metadata.
- At most ONE AI call per user action (use Lovable AI Gateway with LOVABLE_API_KEY if AI is part of the idea).
- Skip tests, skip CI, skip docs pages. Ship the demo, nothing else.

STACK
- React + Vite single page (the index route).
- SSR-safe Privy mount is mandatory. Never import @privy-io/react-auth at
  module scope of a route file — it crashes SSR. Use
  lazy(() => import('./privy-client-entry')) inside <ClientOnly> + <Suspense>,
  and put <PrivyProvider> only inside privy-client-entry.tsx.
- PrivyProvider config (do NOT stub defaultChain as { id, name } — omit it
  or pass viem's `sepolia`; chainId is passed per-call):
    <PrivyProvider appId={import.meta.env.VITE_PRIVY_APP_ID}
      config={{ loginMethods:['google','email'],
                embeddedWallets:{ ethereum:{ createOnLogin:'users-without-wallets' } },
                appearance:{ theme:'dark' } }}>
- Read the embedded wallet from useWallets, not user.wallet:
    const embedded = wallets.find(w => w.walletClientType === 'privy');
- Every send goes through Privy `useSendTransaction` with BOTH `address`
  and `sponsor`, wrapped in a 45s Promise.race timeout whose reject message
  names the exact dashboard toggles:
    await Promise.race([
      sendTransaction(
        { to, data, chainId: 11155111 },
        { address: embedded.address, sponsor: true }
      ),
      new Promise((_, r) => setTimeout(() => r(new Error(
        "Privy sendTransaction timed out after 45s. Enable Gas sponsorship -> App pays -> Ethereum Sepolia -> Allow transactions from the client."
      )), 45_000)),
    ]);
- Do NOT pass uiOptions:{ showWalletUIs:false } — it aborts with
  "signal is aborted without reason". The approval sheet still shows on
  the embedded-EOA path; the fee reads US$0.00.
- Do NOT add ZeroDev / SmartWalletsProvider / a paymaster URL. Native
  Privy sponsorship on Sepolia works with the toggles above and nothing else.
- DASHBOARD PREREQUISITE (one-time): Privy dashboard -> Gas sponsorship
  -> App pays -> add "Ethereum Sepolia" -> toggle "Allow transactions
  from the client" ON. Without this, sendTransaction hangs silently.
- Hardhat in /contracts (kept outside the Vite bundle). Install
  `@nomicfoundation/hardhat-toolbox` AND `@nomicfoundation/hardhat-verify@latest`
  (>=3.x — older versions still hit Etherscan v1 and fail with
  "You are using a deprecated V1 endpoint, switch to Etherscan API V2").
- hardhat.config.cjs MUST use the Etherscan v2 single-key shape (NOT the per-network map):
    require("@nomicfoundation/hardhat-toolbox");
    require("@nomicfoundation/hardhat-verify");
    module.exports = {
      solidity: { version: "0.8.24", settings: { optimizer: { enabled: true, runs: 200 } } },
      networks: { sepolia: {
        url: process.env.SEPOLIA_RPC_URL || "https://ethereum-sepolia-rpc.publicnode.com",
        accounts: [process.env.METAMASK_PRIVATE_KEY.startsWith("0x")
          ? process.env.METAMASK_PRIVATE_KEY : "0x" + process.env.METAMASK_PRIVATE_KEY],
        chainId: 11155111,
      } },
      etherscan: { apiKey: process.env.ETHERSCAN_API_KEY },   // single string, NOT { sepolia: ... }
      sourcify: { enabled: false },                            // silences the v2.x prompt
    };
- Deploy: `npx hardhat run scripts/deploy.cjs --network sepolia`.
- Verify (run RIGHT AFTER deploy, no constructor args for these contracts):
  `npx hardhat verify --network sepolia <address>`
  On success Etherscan returns "Successfully verified contract … on the block explorer"
  and the source becomes readable at
  `https://sepolia.etherscan.io/address/<address>#code`.
- Write the deployed address to `src/data/contract.json` so the UI links to
  `https://sepolia.etherscan.io/address/<address>`.

CONTRACT (contracts/SceneMoodChain.sol):
```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
/// @title SceneMoodChain
/// @notice Record color grading versions on blockchain to secure post-production creative decisions.
/// @notice Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14
contract SceneMoodChain {
    event Logged(address indexed author, string cid, uint256 at);
    /// @notice Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14
    function log(string calldata cid) external {
        emit Logged(msg.sender, cid, block.timestamp);
    }
}
```

USER FLOW
1. Land on page -> 'Sign in with Google' (Privy) -> embedded wallet auto-provisioned.
2. User performs a color grading proof action; the app calls `log(payload)` on the contract via Privy sponsored tx and shows the Etherscan link as proof.
3. Footer renders: "Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14"

REQUIRED SECRETS (Lovable -> Project Settings -> Secrets):
- METAMASK_PRIVATE_KEY  Sepolia deployer key. Fund it: https://cloud.google.com/application/web3/faucet/ethereum/sepolia
- SEPOLIA_RPC_URL       Alchemy Sepolia HTTPS endpoint (https://eth-sepolia.g.alchemy.com/v2/<key>). Create a free app at https://dashboard.alchemy.com/ -> copy the HTTPS URL. Public RPCs throttle/fail under hackathon load — Alchemy is required.
- ETHERSCAN_API_KEY     For `npx hardhat verify`. Get: https://etherscan.io/myapikey
- PRIVY_APP_ID          Google sign-in + sponsored tx. Docs: https://docs.privy.io/llms-full.txt
- PINATA_JWT            IPFS uploads (only if app pins media). Docs: https://docs.pinata.cloud/llms-full.txt

CREDIT (must appear in UI footer AND as NatSpec on every deployed contract):
Built during the Creative AI & Quantum Hackathon organised by StreetKode Fam during Indian Krump Festival 14

Market sizing.

Indicative figures for hackathon pitches — refine with your own research before raising.