contract ERC1155Metadata {
    // URI's default URI prefix
    string internal baseMetadataURI;
    event URI(string _uri, uint256 indexed _id);

    /***********************************|
  |     Metadata Public Function s    |
  |__________________________________*/

    /**
     * @notice A distinct Uniform Resource Identifier (URI) for a given token.
     * @dev URIs are defined in RFC 3986.
     *      URIs are assumed to be deterministically generated based on token ID
     *      Token IDs are assumed to be represented in their hex format in URIs
     * @return URI string
     */
    function uri(uint256 _id) public view returns (string memory) {
        return
            string(abi.encodePacked(baseMetadataURI, _uint2str(_id), ".json"));
    }

    /***********************************|
  |    Metadata Internal Functions    |
  |__________________________________*/

    /**
     * @notice Will emit default URI log event for corresponding token _id
     * @param _tokenIDs Array of IDs of tokens to log default URI
     */
    function _logURIs(uint256[] memory _tokenIDs) internal {
        string memory baseURL = baseMetadataURI;
        string memory tokenURI;

        for (uint256 i = 0; i < _tokenIDs.length; i++) {
            tokenURI = string(
                abi.encodePacked(baseURL, _uint2str(_tokenIDs[i]), ".json")
            );
            emit URI(tokenURI, _tokenIDs[i]);
        }
    }

    /**
     * @notice Will emit a specific URI log event for corresponding token
     * @param _tokenIDs IDs of the token corresponding to the _uris logged
     * @param _URIs    The URIs of the specified _tokenIDs
     */
    function _logURIs(uint256[] memory _tokenIDs, string[] memory _URIs)
        internal
    {
        require(
            _tokenIDs.length == _URIs.length,
            "ERC1155Metadata#_logURIs: INVALID_ARRAYS_LENGTH"
        );
        for (uint256 i = 0; i < _tokenIDs.length; i++) {
            emit URI(_URIs[i], _tokenIDs[i]);
        }
    }

    /**
     * @notice Will update the base URL of token's URI
     * @param _newBaseMetadataURI New base URL of token's URI
     */
    function _setBaseMetadataURI(string memory _newBaseMetadataURI) internal {
        baseMetadataURI = _newBaseMetadataURI;
    }

    /***********************************|
  |    Utility Internal Functions     |
  |__________________________________*/

    /**
     * @notice Convert uint256 to string
     * @param _i Unsigned integer to convert to string
     */
    function _uint2str(uint256 _i)
        internal
        pure
        returns (string memory _uintAsString)
    {
        if (_i == 0) {
            return "0";
        }

        uint256 j = _i;
        uint256 ii = _i;
        uint256 len;

        // Get number of bytes
        while (j != 0) {
            len++;
            j /= 10;
        }

        bytes memory bstr = new bytes(len);
        uint256 k = len - 1;

        // Get each individual ASCII
        while (ii != 0) {
            bstr[k--] = bytes1(uint8(48 + (ii % 10)));
            ii /= 10;
        }

        // Convert to string
        return string(bstr);
    }
}
/**
 * @notice Contract that handles metadata related methods.
 * @dev Methods assume a deterministic generation of URI based on token IDs.
 *      Methods also assume that URI uses hex representation of token IDs.
 */
function _logURIs(uint256[] memory _tokenIDs, string[] memory _URIs)
    internal
{
    require(
        _tokenIDs.length == _URIs.length,
        "ERC1155Metadata#_logURIs: INVALID_ARRAYS_LENGTH"
    );
    for (uint256 i = 0; i < _tokenIDs.length; i++) {
        emit URI(_URIs[i], _tokenIDs[i]);
    }
}

/**
 * @notice Will emit a specific URI log event for corresponding token
 * @param _tokenIDs IDs of the token corresponding to the _uris logged
 * @param _URIs    The URIs of the specified _tokenIDs
 */