Cryo Explorer Ethereum Mainnet

// Dependency file: @openzeppelin/contracts/utils/Context.sol

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/Context.sol)

// pragma solidity ^0.8.0;

/**
 * @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;
    }
}


// Dependency file: @openzeppelin/contracts/access/Ownable.sol

// OpenZeppelin Contracts v4.4.0 (access/Ownable.sol)

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/utils/Context.sol";

/**
 * @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() {
        _transferOwnership(_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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// Dependency file: @openzeppelin/contracts/security/ReentrancyGuard.sol

// OpenZeppelin Contracts v4.4.0 (security/ReentrancyGuard.sol)

// pragma solidity ^0.8.0;

/**
 * @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 making 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;
    }
}


// Dependency file: @openzeppelin/contracts/token/ERC20/IERC20.sol

// OpenZeppelin Contracts v4.4.0 (token/ERC20/IERC20.sol)

// pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}


// Dependency file: contracts/RecoverableErc20ByOwner.sol

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/access/Ownable.sol";
// import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

abstract contract RecoverableErc20ByOwner is Ownable {
    function recoverErc20(address tokenAddress, uint256 amount, address to) external onlyOwner {
        uint256 recoverableAmount = _getRecoverableAmount(tokenAddress);
        require(amount <= recoverableAmount, "RecoverableByOwner: RECOVERABLE_AMOUNT_NOT_ENOUGH");
        _sendErc20(tokenAddress, amount, to);
    }

    function _getRecoverableAmount(address tokenAddress) private view returns (uint256) {
        return IERC20(tokenAddress).balanceOf(address(this));
    }

    function _sendErc20(address tokenAddress, uint256 amount, address to) private {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = tokenAddress.call(abi.encodeWithSelector(0xa9059cbb, to, amount));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "RecoverableByOwner: ERC20_TRANSFER_FAILED");
    }
}


// Dependency file: @openzeppelin/contracts/utils/Address.sol

// OpenZeppelin Contracts v4.4.0 (utils/Address.sol)

// pragma solidity ^0.8.0;

/**
 * @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);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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);
            }
        }
    }
}


// Dependency file: @openzeppelin/contracts/utils/Strings.sol

// OpenZeppelin Contracts v4.4.0 (utils/Strings.sol)

// pragma solidity ^0.8.0;

/**
 * @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);
    }
}


// Dependency file: @openzeppelin/contracts/utils/introspection/IERC165.sol

// OpenZeppelin Contracts v4.4.0 (utils/introspection/IERC165.sol)

// pragma solidity ^0.8.0;

/**
 * @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);
}


// Dependency file: @openzeppelin/contracts/token/ERC721/IERC721.sol

// OpenZeppelin Contracts v4.4.0 (token/ERC721/IERC721.sol)

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/utils/introspection/IERC165.sol";

/**
 * @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;
}


// Dependency file: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol

// OpenZeppelin Contracts v4.4.0 (token/ERC721/IERC721Receiver.sol)

// pragma solidity ^0.8.0;

/**
 * @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);
}


// Dependency file: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol

// OpenZeppelin Contracts v4.4.0 (token/ERC721/extensions/IERC721Metadata.sol)

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

/**
 * @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);
}


// Dependency file: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol

// OpenZeppelin Contracts v4.4.0 (token/ERC721/extensions/IERC721Enumerable.sol)

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

/**
 * @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);
}


// Dependency file: contracts/ProxyRegistry.sol

// pragma solidity ^0.8.0;

contract OwnableDelegateProxy {}

contract ProxyRegistry {
    mapping(address => OwnableDelegateProxy) public proxies;
}


// Dependency file: contracts/interfaces/IRoboTraitsShort.sol

// pragma solidity ^0.8.0;

interface IRoboTraitsShort {
    function contractURI() external view returns (string memory);
    function tokenURI(uint256 tokenId) external view returns (string memory);
}


// Dependency file: contracts/RoborovskiErc721.sol

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/utils/Address.sol";
// import "@openzeppelin/contracts/utils/Strings.sol";
// import "@openzeppelin/contracts/access/Ownable.sol";
// import "@openzeppelin/contracts/utils/introspection/IERC165.sol";
// import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
// import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
// import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
// import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol";
// import "contracts/ProxyRegistry.sol";
// import "contracts/interfaces/IRoboTraitsShort.sol";

abstract contract RoborovskiErc721 is
    Ownable,
    IERC165,
    IERC721,
    IERC721Metadata,
    IERC721Enumerable
{
    using Strings for uint256;
    using Address for address;

    // Metadata
    string private _name = "ROBOROVSKI";
    string private _symbol = "ROBO";
    string private _contractURI = "https://ipfs.io/ipfs/QmXHfdENe1vLPn2g6BP7KnvnhgXGMekst3YaP49hYjXbFY";
    string private _baseURI = "";
    string private _baseExtension = ".json";
    bool private _revealed = false;
    string private _notRevealedURI = "https://ipfs.io/ipfs/QmUCSUQPJuvLbm7ymJ3BFfAc9CYMqCbBX9hoMFQQvP3iTa";
    mapping(uint256 => string) private _tokenURIs;

    // Balances
    uint256 internal constant MAX_SUPPLY = 10000;
    uint256 private _total;
    address[MAX_SUPPLY + 1] private _owners;

    // Approvals
    mapping(uint256 => address) private _tokenApprovals;
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    // Traits
    address public TRAITS;

    // OpenSea
    address private _proxyRegistry;

    constructor(address proxyRegistry_) {
        _proxyRegistry = proxyRegistry_;
    }

    function supportsInterface(bytes4 interfaceId) external pure override returns (bool) {
        return
            interfaceId == type(IERC721Enumerable).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC165).interfaceId;
    }

    function balanceOf(address owner) public view override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        uint256 count = 0;
        uint256 length = _owners.length;
        for (uint256 i = 0; i < length; ++i) {
            if (owner == _owners[i]) {
                ++count;
            }
        }
        delete length;
        return count;
    }

    function ownerOf(uint256 tokenId) public view override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        return owner;
    }

    function rawOwnerOf(uint256 tokenId) public view returns (address) {
        return _owners[tokenId];
    }

    function name() public view override returns (string memory) {
        return _name;
    }

    function symbol() public view override returns (string memory) {
        return _symbol;
    }

    function contractURI() external view returns (string memory) {
        if (TRAITS != address(0))
            return IRoboTraitsShort(TRAITS).contractURI();
        return _contractURI;
    }

    function tokenURI(uint256 tokenId) external view override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        if (!_revealed)
            return _notRevealedURI;

        if (TRAITS != address(0))
            return IRoboTraitsShort(TRAITS).tokenURI(tokenId);

        string memory _tokenURI = _tokenURIs[tokenId];
        if (bytes(_tokenURI).length > 0)
            return _tokenURI;

        return string(abi.encodePacked(_baseURI, tokenId.toString(), _baseExtension));
    }

    function tokenOfOwnerByIndex(address owner, uint256 index) public view override returns (uint256 tokenId) {
        require(index < balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        uint256 count;
        for (uint256 i; i < _owners.length; ++i) {
            if (owner == _owners[i]) {
                if (count == index)
                    return i;
                else
                    ++count;
            }
        }
        require(false, "ERC721Enumerable: owner index out of bounds");
    }

    function tokensOfOwner(address owner) public view returns (uint256[] memory) {
        require(0 < balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        uint256 tokenCount = balanceOf(owner);
        uint256[] memory tokenIds = new uint256[](tokenCount);
        for (uint256 i = 0; i < tokenCount; i++) {
            tokenIds[i] = tokenOfOwnerByIndex(owner, i);
        }
        return tokenIds;
    }

    function totalSupply() public view override returns (uint256) {
        return _total;
    }

    function tokenByIndex(uint256 index) public pure override returns (uint256) {
        return index;
    }

    function approve(address to, uint256 tokenId) public override {
        address owner = 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);
    }

    function getApproved(uint256 tokenId) public view override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");
        return _tokenApprovals[tokenId];
    }

    function setApprovalForAll(address operator, bool approved) public override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    function isApprovedForAll(address owner, address operator) public view override returns (bool) {
        if (_proxyRegistry != address(0) && address(ProxyRegistry(_proxyRegistry).proxies(owner)) == operator)
            return true;
        return _operatorApprovals[owner][operator];
    }

    function transferFrom(address from, address to, uint256 tokenId) public override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _transfer(from, to, tokenId);
    }

    function safeTransferFrom(address from, address to, uint256 tokenId) public override {
        safeTransferFrom(from, to, tokenId, "");
    }

    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    function _exists(uint256 tokenId) internal view returns (bool) {
        return _owners[tokenId] != address(0);
    }

    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ownerOf(tokenId);
        return
            spender == owner ||
            getApproved(tokenId) == spender ||
            isApprovedForAll(owner, spender);
    }

    /*function _safeMint(address to, uint256 tokenId) internal {
        _safeMint(to, tokenId, "");
    }

    function _safeMint(address to, uint256 tokenId, bytes memory _data) internal {
        _mint(to, tokenId);
        require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }*/

    function _mint(address to, uint256 tokenId) internal {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");
        _owners[tokenId] = to;
        _total++;
        emit Transfer(address(0), to, tokenId);
    }

    function _burn(uint256 tokenId) internal {
        address owner = ownerOf(tokenId);
        _approve(address(0), tokenId);
        _owners[tokenId] = address(0);
        _total--;

        if (bytes(_tokenURIs[tokenId]).length != 0)
            delete _tokenURIs[tokenId];

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

    function _transfer(address from, address to, uint256 tokenId) internal {
        require(ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _approve(address(0), tokenId);
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

    function _approve(address to, uint256 tokenId) internal {
        _tokenApprovals[tokenId] = to;
        emit Approval(ownerOf(tokenId), to, tokenId);
    }

    function _setApprovalForAll(address owner, address operator, bool approved) internal {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    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.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;
        }
    }

    // Metadata
    function reveal() external onlyOwner {
        _revealed = true;
    }

    function setNotRevealedURI(string memory uri_) external onlyOwner {
        _notRevealedURI = uri_;
    }

    function setContractURI(string memory uri_) external onlyOwner {
        _contractURI = uri_;
    }

    function setBaseURI(string memory uri_) external onlyOwner {
        _baseURI = uri_;
    }

    function setBaseExtension(string memory fileExtension) external onlyOwner {
        _baseExtension = fileExtension;
    }

    function setTokenURIs(uint256[] memory ids, string[] memory uris) external onlyOwner {
        require(ids.length == uris.length, "ERC721URIStorage: parameters mismatch");
        for (uint256 i = 0; i < ids.length; i++) {
            _setTokenURI(ids[i], uris[i]);
        }
    }

    function _setTokenURI(uint256 tokenId, string memory _tokenURI) private {
        require(_exists(tokenId), "ERC721URIStorage: URI set of nonexistent token");
        _tokenURIs[tokenId] = _tokenURI;
    }

    // Traits
    function setTraits(address traits_) external onlyOwner {
        TRAITS = traits_;
    }

    // OpenSea
    function unsetProxyRegistry() external onlyOwner {
        _proxyRegistry = address(0);
    }
}


// Dependency file: contracts/interfaces/IRnctShort.sol

// pragma solidity ^0.8.0;

interface IRnctShort {
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    function burn(uint256 amount) external;
}


// Dependency file: contracts/RoborovskiName.sol

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/utils/Context.sol";
// import "contracts/RoborovskiErc721.sol";
// import "contracts/interfaces/IRnctShort.sol";

abstract contract RoborovskiName is Context, RoborovskiErc721 {
    uint256 public constant PRICE_CHANGE_NAME = 1830 ether;
    address public immutable RNCT;

    mapping(uint256 => string) private _tokenName;
    mapping(string => bool) private _nameReserved;

    event NameChange(uint256 indexed tokenId, string newName);

    constructor(address rnct_) {
        RNCT = rnct_;
    }

    function burn(uint256 tokenId) external {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Burnable: caller is not owner nor approved");
        _burn(tokenId);

        // If already named, dereserve and remove name
        if (bytes(_tokenName[tokenId]).length != 0) {
            _toggleReserveName(_tokenName[tokenId], false);
            delete _tokenName[tokenId];
            emit NameChange(tokenId, "");
        }
    }

    function tokenName(uint256 tokenId) external view returns (string memory) {
        return _tokenName[tokenId];
    }

    function isNameReserved(string memory nameString) public view returns (bool) {
        return _nameReserved[toLower(nameString)];
    }

    function changeName(uint256 tokenId, string memory newName) external {
        address owner = ownerOf(tokenId);
        require(_msgSender() == owner, "ROBOROVSKI: caller is not the token owner");
        require(validateName(newName) == true, "ROBOROVSKI: not a valid new name");
        require(sha256(bytes(newName)) != sha256(bytes(_tokenName[tokenId])), "ROBOROVSKI: new name is same as the current one");
        require(isNameReserved(newName) == false, "ROBOROVSKI: name already reserved");
        require(IRnctShort(RNCT).transferFrom(_msgSender(), address(this), PRICE_CHANGE_NAME), "ROBOROVSKI: ERC20_TRANSFER_FAILED");
        IRnctShort(RNCT).burn(PRICE_CHANGE_NAME);

        // If already named, dereserve old name
        if (bytes(_tokenName[tokenId]).length > 0) {
            _toggleReserveName(_tokenName[tokenId], false);
        }
        _toggleReserveName(newName, true);
        _tokenName[tokenId] = newName;
        emit NameChange(tokenId, newName);
    }

    // Reserves the name if isReserve is set to true, de-reserves if set to false
    function _toggleReserveName(string memory str, bool isReserve) private {
        _nameReserved[toLower(str)] = isReserve;
    }

    // Check if the name string is valid (Alphanumeric and spaces without leading or trailing space)
    function validateName(string memory str) public pure returns (bool) {
        bytes memory b = bytes(str);
        if (b.length < 1)
            return false;
        // Cannot be longer than 25 characters
        if (b.length > 25)
            return false;
        // Leading space
        if (b[0] == 0x20)
            return false;
        // Trailing space
        if (b[b.length - 1] == 0x20)
            return false;

        bytes1 lastChar = b[0];

        for (uint256 i; i < b.length; i++) {
            bytes1 char = b[i];
            // Cannot contain continous spaces
            if (char == 0x20 && lastChar == 0x20)
                return false;
            if (
                !(char >= 0x30 && char <= 0x39) && //9-0
                !(char >= 0x41 && char <= 0x5A) && //A-Z
                !(char >= 0x61 && char <= 0x7A) && //a-z
                !(char == 0x20) //space
            )
                return false;
            lastChar = char;
        }
        return true;
    }

    // Converts the string to lowercase
    function toLower(string memory str) public pure returns (string memory) {
        bytes memory bStr = bytes(str);
        bytes memory bLower = new bytes(bStr.length);
        for (uint256 i = 0; i < bStr.length; i++) {
            // Uppercase character
            if ((uint8(bStr[i]) >= 65) && (uint8(bStr[i]) <= 90))
                bLower[i] = bytes1(uint8(bStr[i]) + 32);
            else
                bLower[i] = bStr[i];
        }
        return string(bLower);
    }
}


// Dependency file: contracts/RoborovskiProvenance.sol

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/access/Ownable.sol";

abstract contract RoborovskiProvenance is Ownable {
    string public PROVENANCE = "";

    function setProvenance(string memory provenance_) external onlyOwner {
        require(bytes(PROVENANCE).length == 0, "ROBOROVSKI: provenance is already set");
        PROVENANCE = provenance_;
    }
}


// Dependency file: contracts/RoborovskiRandom.sol

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/utils/Context.sol";
// import "contracts/RoborovskiErc721.sol";

abstract contract RoborovskiRandom is Context, RoborovskiErc721 {
    uint256[MAX_SUPPLY] internal _indices;
    uint256 private _randomNonce;

    function _internalMint(address account) internal returns (uint256 tokenId) {
        tokenId = _randomIndex();
        _mint(account, tokenId);
    }

    function _randomIndex() private returns (uint256) {
        uint256 totalSize = MAX_SUPPLY - totalSupply();
        uint256 index = uint256(
            keccak256(abi.encodePacked(_randomNonce++, _msgSender(), block.difficulty, block.timestamp))
        ) % totalSize;

        uint256 value = 0;
        if (_indices[index] != 0)
            value = _indices[index];
        else
            value = index;

        // Move last value to selected position
        if (_indices[totalSize - 1] == 0)
            // Array position not initialized, so use position
            _indices[index] = totalSize - 1;
        else
            // Array position holds a value so use that
            _indices[index] = _indices[totalSize - 1];

        return value + 1;
    }
}


// Dependency file: @openzeppelin/contracts/utils/cryptography/ECDSA.sol

// OpenZeppelin Contracts v4.4.0 (utils/cryptography/ECDSA.sol)

// pragma solidity ^0.8.0;

// import "@openzeppelin/contracts/utils/Strings.sol";

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        } else if (error == RecoverError.InvalidSignatureV) {
            revert("ECDSA: invalid signature 'v' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     *...

// [truncated — 63579 bytes total]