# Verify Node.js installation
node --version   # Should show v18.x.x or higher

# Verify npm installation
npm --version    # Should show 9.x.x or higher

# If using nvm (recommended):
nvm install 18
nvm use 18

# Clone the official FHEVM template
git clone https://github.com/zama-ai/fhevm-hardhat-template.git
cd fhevm-hardhat-template

# Install dependencies
npm install

# Copy the example environment file
cp .env.example .env

# Compile contracts to verify setup
npx hardhat compile

# Run a quick test
npx hardhat test

# If everything passes, your environment is ready!

// Addition
euint32 sum = FHE.add(a, b);

// Subtraction (WRAPS on underflow - see safe patterns)
euint32 diff = FHE.sub(a, b);

// Multiplication
euint32 product = FHE.mul(a, b);

// Greater than
ebool isGreater = FHE.gt(a, b);

// Greater than or equal
ebool isGte = FHE.gte(a, b);

// Less than
ebool isLess = FHE.lt(a, b);

// Equality
ebool isEqual = FHE.eq(a, b);

// Replaces if/else for encrypted conditions
euint32 result = FHE.select(
    condition,      // ebool
    valueIfTrue,    // euint32
    valueIfFalse    // euint32
);

// Step 1 (on-chain): Mark value as publicly decryptable
encryptedValue = FHE.makePubliclyDecryptable(encryptedValue);
bytes32 handle = FHE.toBytes32(encryptedValue);
emit ValueReadyForDecryption(handle);

// Step 2 (off-chain, in frontend):
// Client uses @zama-fhe/relayer-sdk to call publicDecrypt(handle)
// This returns { cleartext, decryptionProof }

// Step 3 (on-chain): Verify and use the decrypted result
function resolveCallback(
    bytes memory cleartexts,
    bytes memory decryptionProof
) external {
    bytes32[] memory handlesList = new bytes32[](1);
    handlesList[0] = handle;
    FHE.checkSignatures(handlesList, cleartexts, decryptionProof);
    uint32 result = abi.decode(cleartexts, (uint32));
    // Use the verified decrypted result...
}