    function participate(
        address _participant,
        uint256 _amount,
        uint256 _duration
    ) external returns (uint256 tokenId) {
        require(_duration >= EPOCH_DURATION, "twTAP: Lock not a week");
    function participate(
        ...
        //@audit tokenId to mint is obtained from `mintedTWTap`
        tokenId = ++mintedTWTap;
        _safeMint(_participant, tokenId);
<br>https:

    function _creditTo(uint16, address _toAddress, uint _tokenId) internal virtual override {
        require(!_exists(_tokenId) || (_exists(_tokenId) && ERC721.ownerOf(_tokenId) == address(this)));
        if (!_exists(_tokenId)) {
            //@audit transfering token N+1 will mint it as it doesnt exists. this will not increment mintedTwTap
            _safeMint(_toAddress, _tokenId);
        } else {
            _transfer(address(this), _toAddress, _tokenId);
        }
    }
    function participate(
        ...
        tokenId = ++mintedTWTap;
        //@audit this will always revert when tokenId already exists
        _safeMint(_participant, tokenId);
