organized_contracts/1c/1c078cd6285362d88ff33103263d97c1be4a36b5258da43cb6a291022560e10f/main.sol

// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023.

/*
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*/

// SPDX-License-Identifier: Unlicense

pragma solidity ^0.8.15;

/*
 * @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 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;
}

/**
 * @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);
}


/**
 * @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;

    }

}



/**

 * @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 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}.

 */

abstract 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 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();

    }

}





/**

 * @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);

    }

}



    struct Collection {

        address token;

        string name;

        string proof;

        uint128 count;

        uint64 testMints;

        bool open;

    }



contract cc0py is ERC721, ERC721Enumerable, Ownable {



    uint256 constant public maxTestMints = 4;

    uint256 constant public maxNFTs = 6969;

    uint256 constant public maxPerCollection = 1111;

    uint256 public maxPerAddress = 2;



    Collection[] collections;



    mapping(address => uint256) public mintsByAddress;



    string private _contractURI = "data:application/json;base64,ewogICJuYW1lIjogImNjMHB5IiwKICAiZGVzY3JpcHRpb24iOiAibm8gbWludCBjb3N0LCBubyBmZWVzLCBubyBmdXR1cmUgcHJvbWlzZXMuIHNwcmVhZCB0aHJvdWdoIGRpc2NvcmQsIGNsYWltcyBsaW1pdGVkIHRvIHR3byBwZXIgYWRkcmVzcy4gY2MwcHkgbWFuaWZlc3RvIGF2YWlsYWJsZSBhcyBhIHJlYWQgZnVuY3Rpb24gb24gdGhlIGNvbnRyYWN0LiIsCiAgImltYWdlIjogImlwZnM6Ly9RbVNtYUF5NVAzQTN4bmE2TVlkNTNwcEhxeG05QTZZNWRjN0JMdW1oWnRHbzRoIiwKICAic2VsbGVyX2ZlZV9iYXNpc19wb2ludHMiOiAwLAogICJmZWVfcmVjaXBpZW50IjogIjB4MDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMCIKfQ==";

    string public manifesto = "https://ipfs.io/ipfs/QmcEGGCYAVyQkQwhYXDG6n7zqFkdE3QEbJqrJvZmV7s7eD";



    constructor() ERC721("cc0py", "cc0py")  {

        _addNewCC0(0x9C8fF314C9Bc7F6e59A9d9225Fb22946427eDC03,"Nouns","https://ipfs.io/ipfs/QmUEbNwuLqd8P8WwSpuB5kqcdjbb3W3tpVh73PXr9HSUZx");

        _addNewCC0(0xd652d2633CDBfD5f27F50cdDb098e708fa8433f3,"XCOPY","https://ipfs.io/ipfs/QmTrAT3DAWNjbvwu84p8pH2UD1jEaAYaBosww3ZL2x8rqz");        

        _addNewCC0(0x23581767a106ae21c074b2276D25e5C3e136a68b,"Moonbirds","https://ipfs.io/ipfs/QmWRv8ZdgVQgVVjn2Bq9ndSN6KXiQTRLD5wFrqgtyEykqt");

        _addNewCC0(0xc143bbfcDBdBEd6d454803804752a064A622C1F3,"Grifters by XCOPY","https://ipfs.io/ipfs/QmbJ5tLsp9UpD7ySvW5wmWbtzfjfNkrnzfyfyjjRsjfTQ4");  

        _addNewCC0(0x42069ABFE407C60cf4ae4112bEDEaD391dBa1cdB,"CryptoDickbutts","https://ipfs.io/ipfs/QmSgBftSWazCMavEU5hFXoXGcjU7WztaXHNmtNdvRiZfjz");              

        _addNewCC0(0x1CB1A5e65610AEFF2551A50f76a87a7d3fB649C6,"CrypToadz by GREMPLIN","https://ipfs.io/ipfs/QmaDhapUHR5zfV4uJryAR5WBwQdsf8DUUZxiQoceSBa41L");

        _addNewCC0(0xbCe3781ae7Ca1a5e050Bd9C4c77369867eBc307e,"goblintown.wtf","https://ipfs.io/ipfs/QmQRiDKZ4XaH866yrCXexDp3AegV1CLMaCox5tWZmuVT8m");

        _addNewCC0(0x79FCDEF22feeD20eDDacbB2587640e45491b757f,"mfers","https://ipfs.io/ipfs/QmWW5XfBm2yfkyHMW4bv5bDB4MY3y9rLdxhTCZMorHXjgc");

    }



    function contractURI() public view returns (string memory) {

        return string(_contractURI);

    }



    function setContractURI(string memory newContractURI) external onlyOwner {

        _contractURI = newContractURI;

    }



    function _addNewCC0(address newContract, string memory name, string memory cc0Proof) internal {

        Collection memory collection;

        collection.token = newContract;

        collection.name = name;

        collection.proof = cc0Proof;

        collections.push(collection);

    }



    function testMint(uint256 collectionID, uint256 id) public onlyOwner {

        collections[collectionID].testMints++;

        require(collections[collectionID].testMints <= maxTestMints);



        _copyNFT(collectionID, id);

    }



    function togglePublic(uint256 collectionID, bool isOpen) public onlyOwner {

        collections[collectionID].open = isOpen;

    }



    /**

     * @notice Collection ID by Name: 0 Nouns, 1 XCOPY, 2 Moonbirds, 3 Grifters, 4 CryptoDickButts, 5 CrypToadz, 6 goblintown.WTF, 7 mfers. See Manifesto for valid ranges

     */

    function copyNFT(uint256 collectionID, uint256 id) public {

        require(collections[collectionID].open, "Not open");

        require(msg.sender == tx.origin, "Only humans");

        require(mintsByAddress[msg.sender] < maxPerAddress, "Don't be greedy!");



        mintsByAddress[msg.sender] = mintsByAddress[msg.sender] + 1;



        _copyNFT(collectionID, id);

    }



    function updateMax(uint256 _maxPerAddress) external onlyOwner {

        maxPerAddress = _maxPerAddress;

    }



    function checkClaimed(uint256 collectionID, uint256 id) public view returns (bool) {

        uint256 tokenId = toTokenId(collectionID, id);

        return _exists(tokenId);

    }



    function _copyNFT(uint256 collectionID, uint256 id) internal {

        require(totalSupply() < maxNFTs, "Max supply reached");

        require(collections[collectionID].count < maxPerCollection, "Collection max supply exceeded");



        IERC721(collections[collectionID].token).ownerOf(id);



        if(collectionID == 3) {

            require(id <= 665);

        }



        uint256 tokenId = toTokenId(collectionID, id);

        collections[collectionID].count++;



        _mint(msg.sender, tokenId);

    }



    function tokenURI(uint256 id) public view override returns (string memory URI) {

        require(_exists(id), "ERC721Metadata: URI query for nonexistent token");



        (uint256 collectionId, uint256 tokenId) = toCollectionId(id);



        string memory uri = IERC721Metadata(collections[collectionId].token).tokenURI(tokenId);



        if (collectionId == 3) {

            return string.concat("ipfs://", uri); //opensea put a bandaid on grifters to allow it to work. must be nice

        }



        return uri;

    }



    function collectionData(uint256 collectionIndex) public view returns (Collection memory) {

        return collections[collectionIndex];

    }



    function toCollectionId(uint256 id) public pure returns (uint256, uint256){

        return (

        id / 1e12,

        id % 1e12

        );

    }



    function toTokenId(uint256 collectionID, uint256 tokenId) public pure returns (uint256) {

        require(tokenId < 1e12, "Invalid tokenId");

        return (collectionID * 1e12) + tokenId;

    }



    function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal override(ERC721, ERC721Enumerable) {

        super._beforeTokenTransfer(from, to, tokenId);

    }



    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC721, ERC721Enumerable) returns (bool) {

        return super.supportsInterface(interfaceId);

    }

}