Deploy a World ID Template App

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

import { ByteHasher } from "./helpers/ByteHasher.sol";
import { IWorldID } from "./interfaces/IWorldID.sol";

contract Contract {
using ByteHasher for bytes;

    ///////////////////////////////////////////////////////////////////////////////
    ///                                  ERRORS                                ///
    //////////////////////////////////////////////////////////////////////////////

    /// @notice Thrown when attempting to reuse a nullifier
    error DuplicateNullifier(uint256 nullifierHash);

    /// @dev The World ID instance that will be used for verifying proofs
    IWorldID internal immutable worldId;

    /// @dev The contract's external nullifier hash
    uint256 internal immutable externalNullifier;

    /// @dev The World ID group ID (always 1)
    uint256 internal immutable groupId = 1;

    /// @dev Whether a nullifier hash has been used already. Used to guarantee an action is only performed once by a single person
    mapping(uint256 => bool) internal nullifierHashes;

    /// @param nullifierHash The nullifier hash for the verified proof
    /// @dev A placeholder event that is emitted when a user successfully verifies with World ID
    event Verified(uint256 nullifierHash);

    /// @param _worldId The WorldID router that will verify the proofs
    /// @param _appId The World ID app ID
    /// @param _actionId The World ID action ID
    constructor(IWorldID _worldId, string memory _appId, string memory _actionId) {
    	worldId = _worldId;
    	externalNullifier = abi.encodePacked(abi.encodePacked(_appId).hashToField(), _actionId).hashToField();
    }

    /// @param signal An arbitrary input from the user, usually the user's wallet address (check README for further details)
    /// @param root The root of the Merkle tree (returned by the JS widget).
    /// @param nullifierHash The nullifier hash for this proof, preventing double signaling (returned by the JS widget).
    /// @param proof The zero-knowledge proof that demonstrates the claimer is registered with World ID (returned by the JS widget).
    /// @dev Feel free to rename this method however you want! We've used `claim`, `verify` or `execute` in the past.
    function verifyAndExecute(address signal, uint256 root, uint256 nullifierHash, uint256[8] calldata proof) public {
    	// First, we make sure this person hasn't done this before
    	if (nullifierHashes[nullifierHash]) revert DuplicateNullifier(nullifierHash);

    	// We now verify the provided proof is valid and the user is verified by World ID
    	worldId.verifyProof(
    		root,
    		groupId,
    		abi.encodePacked(signal).hashToField(),
    		nullifierHash,
    		externalNullifier,
    		proof
    	);

    	// We now record that the user has done this, so they can't do it again (proof of uniqueness)
    	nullifierHashes[nullifierHash] = true;

    	// Finally, execute your logic here, for example issue a token, NFT, etc...
    	// Make sure to emit some kind of event afterwards!

    	emit Verified(nullifierHash);
    }

}