Console NFT Cyber Upgrades

// SPDX-License-Identifier: GPL-3.0

/*
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  +#+        +#+    +:+ +#+ +:+ +#+ +#++:++#++ +#+    +:+ +#+        +#++:++#            +#+ +:+ +#+ :#::+::#       +#+        
 +#+        +#+    +#+ +#+  +#+#+#        +#+ +#+    +#+ +#+        +#+                 +#+  +#+#+# +#+            +#+         
#+#    #+# #+#    #+# #+#   #+#+# #+#    #+# #+#    #+# #+#        #+#                 #+#   #+#+# #+#            #+#          
########   ########  ###    ####  ########   ########  ########## ##########          ###    #### ###            ###           
*/

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    /**
     * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
     * hash matches the root of the tree. When processing the proof, the pairs
     * of leafs & pre-images are assumed to be sorted.
     *
     * _Available since v4.4._
     */
    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }
        return computedHash;
    }
}

contract VRFRequestIDBase {
  /**
   * @notice returns the seed which is actually input to the VRF coordinator
   *
   * @dev To prevent repetition of VRF output due to repetition of the
   * @dev user-supplied seed, that seed is combined in a hash with the
   * @dev user-specific nonce, and the address of the consuming contract. The
   * @dev risk of repetition is mostly mitigated by inclusion of a blockhash in
   * @dev the final seed, but the nonce does protect against repetition in
   * @dev requests which are included in a single block.
   *
   * @param _userSeed VRF seed input provided by user
   * @param _requester Address of the requesting contract
   * @param _nonce User-specific nonce at the time of the request
   */
  function makeVRFInputSeed(
    bytes32 _keyHash,
    uint256 _userSeed,
    address _requester,
    uint256 _nonce
  ) internal pure returns (uint256) {
    return uint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
  }

  /**
   * @notice Returns the id for this request
   * @param _keyHash The serviceAgreement ID to be used for this request
   * @param _vRFInputSeed The seed to be passed directly to the VRF
   * @return The id for this request
   *
   * @dev Note that _vRFInputSeed is not the seed passed by the consuming
   * @dev contract, but the one generated by makeVRFInputSeed
   */
  function makeRequestId(bytes32 _keyHash, uint256 _vRFInputSeed) internal pure returns (bytes32) {
    return keccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
  }
}

// File: https://github.com/smartcontractkit/chainlink/blob/develop/contracts/src/v0.8/interfaces/LinkTokenInterface.sol

interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);

  function approve(address spender, uint256 value) external returns (bool success);

  function balanceOf(address owner) external view returns (uint256 balance);

  function decimals() external view returns (uint8 decimalPlaces);

  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);

  function increaseApproval(address spender, uint256 subtractedValue) external;

  function name() external view returns (string memory tokenName);

  function symbol() external view returns (string memory tokenSymbol);

  function totalSupply() external view returns (uint256 totalTokensIssued);

  function transfer(address to, uint256 value) external returns (bool success);

  function transferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  ) external returns (bool success);

  function transferFrom(
    address from,
    address to,
    uint256 value
  ) external returns (bool success);
}

// File: https://github.com/smartcontractkit/chainlink/blob/develop/contracts/src/v0.8/VRFConsumerBase.sol



/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBase, and can
 * @dev initialize VRFConsumerBase's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumer {
 * @dev     constuctor(<other arguments>, address _vrfCoordinator, address _link)
 * @dev       VRFConsumerBase(_vrfCoordinator, _link) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash), and have told you the minimum LINK
 * @dev price for VRF service. Make sure your contract has sufficient LINK, and
 * @dev call requestRandomness(keyHash, fee, seed), where seed is the input you
 * @dev want to generate randomness from.
 *
 * @dev Once the VRFCoordinator has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomness method.
 *
 * @dev The randomness argument to fulfillRandomness is the actual random value
 * @dev generated from your seed.
 *
 * @dev The requestId argument is generated from the keyHash and the seed by
 * @dev makeRequestId(keyHash, seed). If your contract could have concurrent
 * @dev requests open, you can use the requestId to track which seed is
 * @dev associated with which randomness. See VRFRequestIDBase.sol for more
 * @dev details. (See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.)
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ. (Which is critical to making unpredictable randomness! See the
 * @dev next section.)
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the ultimate input to the VRF is mixed with the block hash of the
 * @dev block in which the request is made, user-provided seeds have no impact
 * @dev on its economic security properties. They are only included for API
 * @dev compatability with previous versions of this contract.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request.
 */
abstract contract VRFConsumerBase is VRFRequestIDBase {
  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBase expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomness the VRF output
   */
  function fulfillRandomness(bytes32 requestId, uint256 randomness) internal virtual;

  /**
   * @dev In order to keep backwards compatibility we have kept the user
   * seed field around. We remove the use of it because given that the blockhash
   * enters later, it overrides whatever randomness the used seed provides.
   * Given that it adds no security, and can easily lead to misunderstandings,
   * we have removed it from usage and can now provide a simpler API.
   */
  uint256 private constant USER_SEED_PLACEHOLDER = 0;

  /**
   * @notice requestRandomness initiates a request for VRF output given _seed
   *
   * @dev The fulfillRandomness method receives the output, once it's provided
   * @dev by the Oracle, and verified by the vrfCoordinator.
   *
   * @dev The _keyHash must already be registered with the VRFCoordinator, and
   * @dev the _fee must exceed the fee specified during registration of the
   * @dev _keyHash.
   *
   * @dev The _seed parameter is vestigial, and is kept only for API
   * @dev compatibility with older versions. It can't *hurt* to mix in some of
   * @dev your own randomness, here, but it's not necessary because the VRF
   * @dev oracle will mix the hash of the block containing your request into the
   * @dev VRF seed it ultimately uses.
   *
   * @param _keyHash ID of public key against which randomness is generated
   * @param _fee The amount of LINK to send with the request
   *
   * @return requestId unique ID for this request
   *
   * @dev The returned requestId can be used to distinguish responses to
   * @dev concurrent requests. It is passed as the first argument to
   * @dev fulfillRandomness.
   */
  function requestRandomness(bytes32 _keyHash, uint256 _fee) internal returns (bytes32 requestId) {
    LINK.transferAndCall(vrfCoordinator, _fee, abi.encode(_keyHash, USER_SEED_PLACEHOLDER));
    // This is the seed passed to VRFCoordinator. The oracle will mix this with
    // the hash of the block containing this request to obtain the seed/input
    // which is finally passed to the VRF cryptographic machinery.
    uint256 vRFSeed = makeVRFInputSeed(_keyHash, USER_SEED_PLACEHOLDER, address(this), nonces[_keyHash]);
    // nonces[_keyHash] must stay in sync with
    // VRFCoordinator.nonces[_keyHash][this], which was incremented by the above
    // successful LINK.transferAndCall (in VRFCoordinator.randomnessRequest).
    // This provides protection against the user repeating their input seed,
    // which would result in a predictable/duplicate output, if multiple such
    // requests appeared in the same block.
    nonces[_keyHash] = nonces[_keyHash] + 1;
    return makeRequestId(_keyHash, vRFSeed);
  }

  LinkTokenInterface internal immutable LINK;
  address private immutable vrfCoordinator;

  // Nonces for each VRF key from which randomness has been requested.
  //
  // Must stay in sync with VRFCoordinator[_keyHash][this]
  mapping(bytes32 => uint256) /* keyHash */ /* nonce */
    private nonces;

  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   * @param _link address of LINK token contract
   *
   * @dev https://docs.chain.link/docs/link-token-contracts
   */
  constructor(address _vrfCoordinator, address _link) {
    vrfCoordinator = _vrfCoordinator;
    LINK = LinkTokenInterface(_link);
  }

  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomness(bytes32 requestId, uint256 randomness) external {
    require(msg.sender == vrfCoordinator, "Only VRFCoordinator can fulfill");
    fulfillRandomness(requestId, randomness);
  }
}

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}


/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}



/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }


    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation. 
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}


/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}


/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}



/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}


/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}


/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) private pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}




/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}


/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        return owner;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "Nonexistent token");

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != _msgSender(), "ERC721: approve to caller");

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, _data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, tokenId);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}



/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}


/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

/// [MIT License]
/// @title Base64
/// @notice Provides a function for encoding some bytes in base64
/// @author Brecht Devos <brecht@loopring.org>
library Base64 {
    bytes internal constant TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    /// @notice Encodes some bytes to the base64 representation
    function encode(bytes memory data) internal pure returns (string memory) {
        uint256 len = data.length;
        if (len == 0) return "";

        // multiply by 4/3 rounded up
        uint256 encodedLen = 4 * ((len + 2) / 3);

        // Add some extra buffer at the end
        bytes memory result = new bytes(encodedLen + 32);

        bytes memory table = TABLE;

        assembly {
            let tablePtr := add(table, 1)
            let resultPtr := add(result, 32)

            for {
                let i := 0
            } lt(i, len) {

            } {
                i := add(i, 3)
                let input := and(mload(add(data, i)), 0xffffff)

                let out := mload(add(tablePtr, and(shr(18, input), 0x3F)))
                out := shl(8, out)
                out := add(out, and(mload(add(tablePtr, and(shr(12, input), 0x3F))), 0xFF))
                out := shl(8, out)
                out := add(out, and(mload(add(tablePtr, and(shr(6, input), 0x3F))), 0xFF))
                out := shl(8, out)
                out := add(out, and(mload(add(tablePtr, and(input, 0x3F))), 0xFF))
                out := shl(224, out)

                mstore(resultPtr, out)

                resultPtr := add(resultPtr, 4)
            }

            switch mod(len, 3)
            case 1 {
                mstore(sub(resultPtr, 2), shl(240, 0x3d3d))
            }
            case 2 {
                mstore(sub(resultPtr, 1), shl(248, 0x3d))
            }

            mstore(result, encodedLen)
        }

        return string(result);
    }
}

abstract contract PercentageGenerator {
	function calculatePercentage(bool hasVault, uint rarity, uint tokens) public view virtual returns (uint[] memory);
}

abstract contract SourceData {
	function getVaultRarity(uint token_id) public view virtual returns(uint);
    function getFirstStat(uint token_id, uint rarity) public view virtual returns(uint);
    function getFirstStatValue(uint token_id, uint rarity) public view virtual returns(uint);
    function getSecondStat(uint token_id, uint rarity) public view virtual returns(uint);
    function getSecondStatValue(uint token_id, uint rarity) public view virtual returns(uint);
    function getFirstAugment(uint token_id, uint rarity) public view virtual returns(uint);
    function getSecondAugment(uint token_id, uint rarity) public view virtual returns(uint);
    function getAirdrops(uint token_id, uint rarity) public view virtual returns(uint);
}

contract ConsoleNFT_Cyber_Upgrades is ERC721Enumerable, ReentrancyGuard, Ownable, VRFConsumerBase {

	address dataContract;
    address percentageContract;
    address vaultContract;
    address levelUpContract;

    mapping(uint => bool) private _usedVaults;

    // Mapping for wallet addresses that have previously minted
    mapping(address => uint) private _whitelistMinters;

    // Merkle Proof Hashes for tokens
    bytes32[] public rootHashes;

	uint public constant maxTokens = 5000;

    uint public vaultHolderReserves = 500;

    uint[] public rarities; // mapping of pool rarities in constructor

    uint public total = 0;

	uint mintCost = 0.05 ether;
    uint publicMintCost = 0.1 ether;

    uint public whitelistMintStart;
    uint public publicMintStart;

	bool sysAdminMinted;
	bool error404Minted;
	bool code200Minted;
	bool giveawaysMinted;
	
	address error404Address;
	address code200Address;
	address giveawaysAddress;

    mapping(uint => uint) public levels; // tokenID -> level
    mapping(uint => uint) public rarity; // tokenID -> rarity

    function setMerkleHashes(bytes32[] memory _rootHash) external onlyOwner {
        rootHashes = new bytes32[](0);
        for (uint i=0; i < _rootHash.length; i++) {
            rootHashes.push(_rootHash[i]);
        }
    }

    function setVaultContractAddress(address _vaultContract) external onlyOwner {
        vaultContract = _vaultContract;
    }

    function setPercentageContractAddress(address _percentageContract) external onlyOwner {
        percentageContract = _percentageContract;
    }

    function setWhitelistMintStart(uint _timestamp) external onlyOwner {
        whitelistMintStart = _timestamp;
    }
	
    function setPublicMintStart(uint _timestamp) external onlyOwner {
        publicMintStart = _timestamp;
    }

	function setSourceData(address _dataContract) external onlyOwner {
        dataContract = _dataContract;
    }

    function setLevelUpContract(address _levelUpContract) external onlyOwner {
        levelUpContract = _levelUpContract;
    }

	string[] private rarityText = [
        "Common",
        "Uncommon",
        "Rare",
        "Epic",
        "Legendary"
    ];

    function getRarity(uint256 tokenId) public view returns (string memory) {
        require(_exists(tokenId), "Nonexistent token");
		
        string memory output;
		
        output = rarityText[rarity[tokenId]];
		
        return output;
    }

    string[] private firstStat = [
        "Health",
        "Strength",
        "Speed",
        "Accuracy",
        "Intelligence",
        "Tech",
        "Hack speed",
        "SQL skill",
        "Network",
        "DNA",
        "De-auth",
        "Pwd cracking",
        "XSS forgery",
        "Decrypt",
        "Cryptography"
    ];

    function getFirstStat(uint256 tokenId) public view returns (string memory) {
        require(_exists(tokenId), "Nonexistent token");
		
        string memory output;
		
		SourceData source_data = SourceData(dataContract);
		
        output = firstStat[source_data.getFirstStat(tokenId, rarity[tokenId])];
		
        return output;
    }

    function getFirstStatValue(uint256 tokenId) public view returns (uint) {
        require(_exists(tokenId), "Nonexistent token");
		
        uint output;
		
		SourceData source_data = SourceData(dataContract);
		
		uint firstStatValue = source_data.getFirstStatValue(tokenId, rarity[tokenId]);
		
        output = (firstStatValue * getItemLevel(tokenId)) + 1;
		
        return output;
    }

    string[] private secondStat = [
        "Lockpicking",
        "Regeneration",
        "Armor",
        "Backpack",
        "Intelligence",
        "Charge",
        "Damage boost",
        "Reflexes",
        "Radar",
        "Keymaster",
        "Pickpocket",
        "EMP shield",
        "EMP power",
        "Run silent",
        "Nanotech"
    ];

    function getSecondStat(uint256 tokenId) public view returns (string memory) {
        require(_exists(tokenId), "Nonexistent token");
		
        string memory output;
		
		SourceData source_data = SourceData(dataContract);
		
        output = secondStat[source_data.getSecondStat(tokenId, rarity[tokenId])];
		
        return output;
    }

    function getSecondStatValue(uint256 tokenId) public view returns (uint) {
        require(_exists(tokenId), "Nonexistent token");
		
        uint output;
		
		SourceData source_data = SourceData(dataContract);
		
		uint secondStatValue = source_data.getSecondStatValue(tokenId, rarity[tokenId]);
		
        output = (secondStatValue * getItemLevel(tokenId)) + 1;
		
        return output;
    }

    string[] private firstAugment = [
        "Scrapper",
        "Bionic Arms",
        "Detoxifier",
        "Bionic Lungs",
        "Hardened Bones",
        "Berserk",
        "Blood pump",
        "Edge runner",
        "Adrenaline Pump",
        "Bloodware",
        "Cyber Joints",
        "Cloaking",
        "Nanobots",
        "Synthetic Heart",
        "?"
    ];

    function getFirstAugment(uint256 tokenId) public view returns (string memory) {
        require(_exists(tokenId), "Nonexistent token");
		
        string memory output;
		
		SourceData source_data = SourceData(dataContract);
		
        output = firstAugment[source_data.getFirstAugment(tokenId, rarity[tokenId])];
		
        return output;
    }

    string[] private secondAugment = [
        "Nightvision",
        "Titan Knuckles",
        "Cyber Legs",
        "Cyber Arms",
        "Reflex Boost",
        "Lizard skin",
        "Titanium Bones",
        "Echolocation",
        "Thermal vision",
        "X-ray Vision",
        "Shapeshifter",
        "Exoskeleton",
        "Stealth kit",
        "Double Heart",
        "?"
    ];

    function getSecondAugment(uint256 tokenId) public view returns (string memory) {
        require(_exists(tokenId), "Nonexistent token");
		
        string memory output;
		
		SourceData source_data = SourceData(dataContract);
		
        output = secondAugment[source_data.getSecondAugment(tokenId, rarity[tokenId])];
		
        return output;
    }

    function getAirdrops(uint256 tokenId) public view returns (uint) {
        require(_exists(tokenId), "Nonexistent token");
		
        uint output;
		
		SourceData source_data = SourceData(dataContract);
		
        output = source_data.getAirdrops(tokenId, rarity[tokenId]) + getItemLevel(tokenId);
		
        return output;
    }
	
    string internal baseTokenURI;

	function setBaseTokenURI(string memory _uri) external onlyOwner {
        baseTokenURI = _uri;
    }

    string internal externalURI;

	function setExternalURI(string memory _uri) external onlyOwner {
        externalURI = _uri;
    }

	function tokenURI(uint _tokenId) public view override returns (string memory) {
        require(_exists(_tokenId), "Query for non-existent token!");

        string[7] memory json;

        json[0] = string(
			abi.encodePacked('{',
                '"name": "Cyber Upgrade #', t(_tokenId), ' (Level: ', t(getItemLevel(_tokenId)), ')",',
                '"image": "', baseTokenURI, t(rarity[_tokenId]), '.jpg",',
                '"external_url": "', externalURI, '?dna=', getDna(_tokenId) ,'&id=', t(_tokenId) ,'",',  
                '"description": "Upgrades waiting to be connected to players.",',
                '"attributes": ['
            )
		);

        json[1] = string(
			abi.encodePacked(
				'{',
					'"trait_type": "Rarity",',
					'"value": "', getRarity(_tokenId) ,'"',
                '},',
                '{',
                    '"trait_type": "Level",',
                    '"value": "', t(getItemLevel(_tokenId)) ,'"',
                '},'
            )
		);
        json[2] = string(
			abi.encodePacked(
				'{',
                    '"trait_type": "Upgrade #1",',
                    '"value": "', getFirstStat(_tokenId) , " +", t(getFirstStatValue(_tokenId)) ,'"',
                '},'
            )
		);

        json[3] = string(
			abi.encodePacked(
				'{',
                    '"trait_type": "Upgrade #2",',
                    '"value": "', getSecondStat(_tokenId) ," +", t(getSecondStatValue(_tokenId)) ,'"',
                '},'
            )
		);
        json[4] = string(
			abi.encodePacked(
				'{',
                    '"trait_type": "Augmentation #1",',
                    '"value": "', getFirstAugment(_tokenId) ,'"',
                '},'
            )
		);
        json[5] = string(
			abi.encodePacked(
                '{',
                    '"trait_type": "Augmentation #2",',
                    '"value": "', getSecondAugment(_tokenId) ,'"',
                '},',
                '{',
                    '"trait_type": "Airdrops",',
					'"value": "x', t(getAirdrops(_tokenId)) ,'"',
                '}'
            )
		);
        json[6] = string(
			abi.encodePacked('],',
                '"animation_url": "', externalURI, '?dna=', getDna(_tokenId) , '&id=', t(_tokenId) , '",',
                '"iframe_url": "', externalURI, '?dna=', getDna(_tokenId) , '&id=', t(_tokenId) , '"',
            '}')
		);

        string memory result = Base64.encode(
            bytes(
                string(
                    abi.encodePacked(
                        json[0],
                        json[1],
                        json[2],
                        json[3],
                        json[4],
                        json[5],
                        json[6]
                    )
                )
            )
        );

        return string(abi.encodePacked("data:application/json;base64,", result));
    }


	
	// helper
	function t(uint _tokenId) public pure returns (string memory) {
		return Strings.toString(_tokenId);
	}


    // Getters
    function getDna(uint256 tokenId) public view returns (string memory) {
        require(_exists(tokenId), "Query for non-existent token!");

        SourceData source_data = SourceData(dataContract);

        // First stat index
        uint firstStatIndex = source_data.getFirstStat(tokenId, rarity[tokenId]);

        // First stat index
        uint secondStatIndex = source_data.getSecondStat(tokenId, rarity[tokenId]);

        string[2] memory dna;

        dna[0] = string(
            abi.encodePacked(
                t(rarity[tokenId]), "-",
                t(levels[tokenId]), "-",
                t(firstStatIndex), "-",
                t(getFirstStatValue(tokenId)), "-"
            )
        );
        
        dna[1] = string(
			abi.encodePacked(
                t(secondStatIndex), "-",
                t(getSecondStatValue(tokenId)), "-",
                t(source_data.getFirstAugment(tokenId, rarity[tokenId])), "-",
                t(source_data.getSecondAugment(tokenId, rarity[tokenId])), "-",
                t(getAirdrops(tokenId))
            )
		);

        string memory result = string(
                    abi.encodePacked(
                        dna[0],
                        dna[1]
                    )
                );

        return string(abi.encodePacked(result));
    }

    function getItemLevel(uint256 tokenId) public view returns (uint) {
        return levels[tokenId];
    }

    function setItemLevel(uint tokenId, uint level) external {
        require(msg.sender == levelUpContract, "You can not call this");
        levels[tokenId] = level;
    }

	function whitelistClaim(bytes32[] memory proof, uint proofNumber) public nonReentrant payable {
        require(whitelistMintStart < block.timestamp, "Whitelist mint not started yet");
        require(maxTokens - total > vaultHolderReserves, "Minting over vault holder limit");
        require(total < maxTokens, "All tokens are already minted");
		require(msg.value == mintCost, "Incorrect mint cost value");
        require(_whitelistMinters[_msgSender()] < 1, "You've already minted");
		
		// Merkle tree validation
		bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
		require(MerkleProof.verify(proof, rootHashes[proofNumber], leaf), "Invalid proof");
		
		uint userTokens = proofNumber * 1000;
                
		// Proceed in minting process
		uint tokenId = getVRFRandomIndex(false, 0, userTokens);
		total++;

		// Set the _whitelistMinters value to tokenId for this address as it has minted
		_whitelistMinters[_msgSender()] = tokenId;

		_safeMint(_msgSender(), tokenId);
		
    }

    function publicClaim(uint numberOfTokens) public nonReentrant payable {
        require(publicMintStart < block.timestamp, "Public mint did not start yet");
        require(maxTokens - total > vaultHolderReserves, "Minting over vault holder limit");
        require(total + numberOfTokens < maxTokens, "All tokens are already minted");
        require(numberOfTokens > 0, "Can not mint zero tokens");
        require(numberOfTokens < 11, "Request exceeds max tokens");
		require(msg.value == publicMintCost * numberOfTokens, "Incorrect mint cost value");

        for (uint i=1; i < numberOfTokens; i++) {
            uint tokenId = getVRFRandomIndex(false, 0, 0);
            total++;
            _safeMint(_msgSender(), tokenId);
        }

    }

    function vaultHolderClaim(bytes32[] memory proof, uint proofNumber, uint[] memory vaultIds) public nonReentrant {
        require(whitelistMintStart < block.timestamp, "Whitelist mint not started yet");
        require(total + vaultIds.length < maxTokens, "Mint over the max tokens limit");

        for (uint i=0; i < vaultIds.length; i++) {
            require(validateVaultOwnership(vaultIds[i]), "Not Vault owner");
            require(!checkUsedVault(vaultIds[i]), "Vault was already used");
        }
		
		// This sender does not necessary need to have tokens, it is optional
        uint userTokens = 0;

        // Merkle tree for getting tokens
		bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
		
		if (MerkleProof.verify(proof, rootHashes[proofNumber], leaf) ) {

			userTokens = proofNumber * 1000;

		}

        for (uint i=0; i < vaultIds.length; i++) {

            // get vault rarity
            uint tokenId = getVRFRandomIndex(true, getVaultRarity(vaultIds[i]), userTokens);
            _usedVaults[vaultIds[i]] = true;

            total++;
            vaultHolderReserves--;
            _safeMint(_msgSender(), tokenId);
        }

    }
    
    function vaultHolderClaimCombined(bytes32[] memory proof, uint proofNumber, uint[] memory vaultIds) public nonReentrant payable {
        require(whitelistMintStart < block.timestamp, "Whitelist mint not started yet");
        require(total + 1 + vaultIds.length < maxTokens, "Mint over the max tokens limit");
        require(msg.value == mintCost, "Incorrect mint cost value");
        require(_whitelistMinters[_msgSender()] < 1, "You've already minted");

        for (uint i=0; i < vaultIds.length; i++) {
            require(validateVaultOwnership(vaultIds[i]), "Not Vault owner");
            require(!checkUsedVault(vaultIds[i]), "Vault was already used");
        }

        uint userTokens = 0;

        // Merkle tree for getting tokens
		bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
		require(MerkleProof.verify(proof, rootHashes[proofNumber], leaf), "Invalid proof");
		
        userTokens = proofNumber * 1000;

        // Continue minting process
        for (uint i=0; i < vaultIds.length; i++) {
            uint tokenId = getVRFRandomIndex(true, getVaultRarity(vaultIds[i]), userTokens);
            _usedVaults[vaultIds[i]] = true;

            total++;
            vaultHolderReserves--;
            _safeMint(_msgSender(), tokenId);
        }

        // + 1 for whitelist
        uint additionalTokenId = getVRFRandomIndex(false, 0, userTokens);
        total++;
        _whitelistMinters[_msgSender()] = additionalTokenId;
        _safeMint(_msgSender(), additionalTokenId);

    }

    function validateVaultOwnership(uint _vaultID) internal view returns(bool) {
        ERC721 vaultContractData = ERC721(vaultContract);
        if(vaultContractData.ownerOf(_vaultID) == msg.sender) {
            return true;
        }
        return false;
    }

    function checkUsedVault(uint _vaultID) internal view returns(bool) {
        if (_usedVaults[_vaultID] == true) {
            return true;
        }
        return false;
    }

    function vaultCheck(uint _vaultID) public view returns (bool) {
        if (_usedVaults[_vaultID] == true) {
            return true;
        }
        return false;
    }
	
    function getVaultRarity(uint _vaultID) public view returns (uint) {

		uint output;
		
		SourceData source_data = SourceData(dataContract);
		
        output = source_data.getVaultRarity(_vaultID);
		
        return output;

    }

	function sysAdminClaim() public onlyOwner nonReentrant {
		require(sysAdminMinted == false, "Already minted!");
		
		sysAdminMinted = true;
		uint tokenId = getVRFRandomIndex(false, 0, 0);
        total++;
        _safeMint(owner(), tokenId);
    }

	function error404Claim() public nonReentrant {
		require(msg.sender == error404Address, "Not Error 404");
		require(error404Minted == false, "Already minted!");
		
		error404Minted = true;
		uint tokenId = getVRFRandomIndex(false, 0, 0);
        total++;
        _safeMint(msg.sender, tokenId);
    }
	
	function code200Claim() public nonReentrant {
		require(msg.sender == code200Address, "Not Code 200");
		require(code200Minted == false, "Already minted!");
		
		code200Minted = true;
		uint tokenId = getVRFRandomIndex(false, 0, 0);
        total++;
        _safeMint(msg.sender, tokenId);
    }
	
	function giveawaysClaim() public nonReentrant {
		require(msg.sender == giveawaysAddress, "Not Giveaways wallet");
		require(giveawaysMinted == false, "Already minted!");
		
		giveawaysMinted = true;

        for (uint i=0; i < 20; i++) {
            uint tokenId = getVRFRandomIndex(false, 0, 0);
            total++;
            _safeMint(msg.sender, tokenId);
        }
		
    }
	
    constructor() ERC721("Console NFT Cyber Upgrades", "Cnsl-NFT-U") VRFConsumerBase(
        0xf0d54349aDdcf704F77AE15b96510dEA15cb7952,
        0x514910771AF9Ca656af840dff83E8264EcF986CA
    ) 
	Ownable() {
        keyHash = 0xAA77729D3466CA35AE8D28B3BBAC7CC36A5031EFDC430821C02BC31A238AF445;	
        fee = 2 * (10**18);
		
		error404Address = 0x24Db9e45f6aC29175030A083B985C184A02c2d64;
		code200Address = 0x1C0d3B190B18b4452BD4d0928D7f425eA9A0B3F9;
		giveawaysAddress = 0x7e95c71bDF0E0526eA534Fb5191ceD999190c117;

        whitelistMintStart = 1644330600; // 8. february 2022 - 14:30 UTC
        publicMintStart = 1644359400; // 8. february 2022 - 23:30 UTC (+8 hours)
        
        rarities.push(3250); // Common - 65%
        rarities.push(1000); // Uncommon - 20%
        rarities.push(475); // Rare - 9.5%
        rarities.push(225); // Epic - 4.5%
        rarities.push(50); // Legendary - 1%
    }


	////////////////////////// VRF /////////////////////////////
	
    bytes32 internal keyHash;
    uint internal fee;
    uint internal randomResult;
    
    // VRF Functions
    function getRandomNumber() public onlyOwner returns (bytes32 requestId) {
        require(LINK.balanceOf(address(this)) >= fee, "Not enough LINK!");
        return requestRandomness(keyHash, fee);
    }
    function fulfillRandomness(bytes32 requestId, uint randomness) internal override {
        randomResult = randomness;
    }
    function getRandomResult() public view onlyOwner returns (uint) {
        return randomResult;
    }

    // >>> Now, the VRF is stored in [uint internal randomResult]
    ////////////////////////// VRF /////////////////////////////

    /////////////////////// Token ID Generator ////////////////////////

    uint[maxTokens] internal indices;
    uint32 internal nonce;

    function getVRFRandomIndex(bool hasVault, uint vaultRarity, uint _userTokens) internal returns (uint) {
        require(randomResult != 0, "VRF Random Result has not been set!");

        // Get the random token ID
        uint _tokensRemaining = maxTokens - total; // require that this calculation is possible from all caller functions
        uint _maxIndex = _tokensRemaining == 0 ? 0 : _tokensRemaining - 1; // shorthand if for safety
        uint _rand = uint(keccak256(abi.encodePacked(randomResult, nonce, msg.sender, block.difficulty, block.timestamp))) % _tokensRemaining;
    
        uint _output = 0;

        _output = indices[_rand] != 0 ? indices[_rand] :_rand;
        indices[_rand] = indices[_maxIndex] == 0 ? _maxIndex : indices[_maxIndex];

        uint32 _nonceAdd = uint32(uint256(keccak256(abi.encodePacked(randomResult, nonce, msg.sender, block.difficulty, block.timestamp)))) % 10;
        nonce += _nonceAdd; 


        // Get the data from Percentage Contract
        PercentageGenerator percentage = PercentageGenerator(percentageContract);
        uint[] memory percentageArray = percentage.calculatePercentage(hasVault, vaultRarity, _userTokens);

        // Construct view array of 10k items to pick from
        // Because of rounding errors there might be close but not exactly 10k items, this should be safe
        uint totalItems;
        uint[] memory percentageNumbers = new uint[](5);
        for (uint i=0; i < percentageArray.length; i++) {
            totalItems += percentageArray[i];
            percentageNumbers[i] = totalItems;
        }

        // VRF guess the number in 10k items to get the rarity
        uint _randRarity = uint(keccak256(abi.encodePacked(randomResult, nonce, msg.sender, block.difficulty, block.timestamp))) % totalItems;

        uint rarityResult = 0; // Common as base

        // Get the rarity based on the VRF result
        if (_randRarity >= percentageNumbers[0] && _randRarity < percentageNumbers[1]) {
            rarityResult = 1; // Uncommon
        }
        if (_randRarity >= percentageNumbers[1] && _randRarity < percentageNumbers[2]) {
            rarityResult = 2; // Rare
        }
        if (_randRarity >= percentageNumbers[2] && _randRarity < percentageNumbers[3]) {
            rarityResult = 3; // Rpic
        }
        if (_randRarity >= percentageNumbers[3] && _randRarity <= percentageNumbers[4]) {
            rarityResult = 4; // Legendary
        }

        // If rarity no longer exist in the pool, give lower rarity
        if (rarities[rarityResult] > 0) {
            
            rarities[rarityResult]--;

            // There is still enough in the rarity pool
            // Assign rarity to this token ID
            rarity[_output] = rarityResult;

            // Assign starting level
            levels[_output] = 1;
        }
        else {
            // give other rarity, up or down
            rarity[_output] = pickOtherRarity(rarityResult);
        }

        return _output;
    }

    function pickOtherRarity(uint rarityResult) internal returns (uint) {
		
		bool direction; // default false = down
		
        if (rarities[rarityResult] > 0) {
            return rarityResult;
        }
        else {
            if(rarityResult == 4){	
                direction = false;
            }
            if(rarityResult == 0){
                direction = true;
        	}
            if(direction == true){ 
                rarityResult++;
            } else {
                rarityResult--;
            }
            if( rarities[rarityResult] > 0 ) {	
                return rarityResult;
            } else {
                return pickOtherRarity(rarityResult);
            }
        }

    }

    /////////////////////// Token ID Generator ////////////////////////
	
	// Withdraw Ether
    function withdrawEther() public onlyOwner {
        payable(msg.sender).transfer(address(this).balance); 
    }

}

{
  "compilationTarget": {
    "ConsoleNFT_Cyber_Upgrades.sol": "ConsoleNFT_Cyber_Upgrades"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}