// SPDX-License-Identifier: MIT

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;
    }
}

/**
 * @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 String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

/**
 * @dev 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 Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

/**
 * @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 Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

/**
 * @dev 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 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);
}

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

/**
 * @title ERC-721 Non-Fungible Token Standard, optional 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 Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata and Enumerable extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
 *
 * Assumes the number of issuable tokens (collection size) is capped and fits in a uint128.
 *
 * Does not support burning tokens to address(0).
 */
 contract ERC721A is
 Context,
 ERC165,
 IERC721,
 IERC721Metadata,
 IERC721Enumerable
{
 using Address for address;
 using Strings for uint256;

 struct TokenOwnership {
   address addr;
   uint64 startTimestamp;
 }

 struct AddressData {
   uint128 balance;
   uint128 numberMinted;
 }

 uint256 private currentIndex = 1;

 uint256 internal immutable collectionSize;
 uint256 internal immutable maxBatchSize;

 // Token name
 string private _name;

 // Token symbol
 string private _symbol;

 // Mapping from token ID to ownership details
 // An empty struct value does not necessarily mean the token is unowned. See ownershipOf implementation for details.
 mapping(uint256 => TokenOwnership) private _ownerships;

 // Mapping owner address to address data
 mapping(address => AddressData) private _addressData;

 // 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
  * `maxBatchSize` refers to how much a minter can mint at a time.
  * `collectionSize_` refers to how many tokens are in the collection.
  */
 constructor(
   string memory name_,
   string memory symbol_,
   uint256 maxBatchSize_,
   uint256 collectionSize_
 ) {
   require(
     collectionSize_ > 0,
     "ERC721A: collection must have a nonzero supply"
   );
   require(maxBatchSize_ > 0, "ERC721A: max batch size must be nonzero");
   _name = name_;
   _symbol = symbol_;
   maxBatchSize = maxBatchSize_;
   collectionSize = collectionSize_;
 }

 /**
  * @dev See {IERC721Enumerable-totalSupply}.
  */
 function totalSupply() public view override returns (uint256) {
   return currentIndex - 1;
 }

 /**
  * @dev See {IERC721Enumerable-tokenByIndex}.
  */
 function tokenByIndex(uint256 index) public view override returns (uint256) {
   require(index < totalSupply() + 1, "ERC721A: global index out of bounds");
   return index;
 }

 /**
  * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
  * This read function is O(collectionSize). If calling from a separate contract, be sure to test gas first.
  * It may also degrade with extremely large collection sizes (e.g >> 10000), test for your use case.
  */
 function tokenOfOwnerByIndex(address owner, uint256 index)
   public
   view
   override
   returns (uint256)
 {
   require(index < balanceOf(owner) + 1, "ERC721A: owner index out of bounds");
   uint256 numMintedSoFar = totalSupply() + 1;
   uint256 tokenIdsIdx = 1;
   address currOwnershipAddr = address(0);
   for (uint256 i = 1; i < numMintedSoFar; i++) {
     TokenOwnership memory ownership = _ownerships[i];
     if (ownership.addr != address(0)) {
       currOwnershipAddr = ownership.addr;
     }
     if (currOwnershipAddr == owner) {
       if (tokenIdsIdx == index) {
         return i;
       }
       tokenIdsIdx++;
     }
   }
   revert("ERC721A: unable to get token of owner by index");
 }

 /**
  * @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 ||
     interfaceId == type(IERC721Enumerable).interfaceId ||
     super.supportsInterface(interfaceId);
 }

 /**
  * @dev See {IERC721-balanceOf}.
  */
 function balanceOf(address owner) public view override returns (uint256) {
   require(owner != address(0), "ERC721A: balance query for the zero address");
   return uint256(_addressData[owner].balance);
 }

 function _numberMinted(address owner) internal view returns (uint256) {
   require(
     owner != address(0),
     "ERC721A: number minted query for the zero address"
   );
   return uint256(_addressData[owner].numberMinted);
 }

 function ownershipOf(uint256 tokenId)
   internal
   view
   returns (TokenOwnership memory)
 {
   require(_exists(tokenId), "ERC721A: owner query for nonexistent token");

   uint256 lowestTokenToCheck;
   if (tokenId >= maxBatchSize) {
     lowestTokenToCheck = tokenId - maxBatchSize + 1;
   }

   for (uint256 curr = tokenId; curr >= lowestTokenToCheck; curr--) {
     TokenOwnership memory ownership = _ownerships[curr];
     if (ownership.addr != address(0)) {
       return ownership;
     }
   }

   revert("ERC721A: unable to determine the owner of token");
 }

 /**
  * @dev See {IERC721-ownerOf}.
  */
 function ownerOf(uint256 tokenId) public view override returns (address) {
   return ownershipOf(tokenId).addr;
 }

 /**
  * @dev See {IERC721Metadata-name}.
  */
 function name() public view virtual override returns (string memory) {
   return _name;
 }

 /**
  * @dev See {IERC721Metadata-symbol}.
  */
 function symbol() public view virtual override returns (string memory) {
   return _symbol;
 }

 /**
  * @dev See {IERC721Metadata-tokenURI}.
  */
 function tokenURI(uint256 tokenId)
   public
   view
   virtual
   override
   returns (string memory)
 {
   require(
     _exists(tokenId),
     "ERC721Metadata: URI query for nonexistent token"
   );

   string memory baseURI = _baseURI();
   return
     bytes(baseURI).length > 0
       ? string(abi.encodePacked(baseURI, tokenId.toString()))
       : "";
 }

 /**
  * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
  * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
  * by default, can be overriden in child contracts.
  */
 function _baseURI() internal view virtual returns (string memory) {
   return "";
 }

 /**
  * @dev See {IERC721-approve}.
  */
 function approve(address to, uint256 tokenId) public override {
   address owner = ERC721A.ownerOf(tokenId);
   require(to != owner, "ERC721A: approval to current owner");

   require(
     _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
     "ERC721A: approve caller is not owner nor approved for all"
   );

   _approve(to, tokenId, owner);
 }

 /**
  * @dev See {IERC721-getApproved}.
  */
 function getApproved(uint256 tokenId) public view override returns (address) {
   require(_exists(tokenId), "ERC721A: approved query for nonexistent token");

   return _tokenApprovals[tokenId];
 }

 /**
  * @dev See {IERC721-setApprovalForAll}.
  */
 function setApprovalForAll(address operator, bool approved) public override {
   require(operator != _msgSender(), "ERC721A: 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 override {
   _transfer(from, to, tokenId);
 }

 /**
  * @dev See {IERC721-safeTransferFrom}.
  */
 function safeTransferFrom(
   address from,
   address to,
   uint256 tokenId
 ) public override {
   safeTransferFrom(from, to, tokenId, "");
 }

 /**
  * @dev See {IERC721-safeTransferFrom}.
  */
 function safeTransferFrom(
   address from,
   address to,
   uint256 tokenId,
   bytes memory _data
 ) public override {
   _transfer(from, to, tokenId);
   require(
     _checkOnERC721Received(from, to, tokenId, _data),
     "ERC721A: 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`),
  */
 function _exists(uint256 tokenId) internal view returns (bool) {
   return tokenId < currentIndex;
 }

 function _safeMint(address to, uint256 quantity) internal {
   _safeMint(to, quantity, "");
 }

 /**
  * @dev Mints `quantity` tokens and transfers them to `to`.
  *
  * Requirements:
  *
  * - there must be `quantity` tokens remaining unminted in the total collection.
  * - `to` cannot be the zero address.
  * - `quantity` cannot be larger than the max batch size.
  *
  * Emits a {Transfer} event.
  */
 function _safeMint(
   address to,
   uint256 quantity,
   bytes memory _data
 ) internal {
   uint256 startTokenId = currentIndex;
   require(to != address(0), "ERC721A: mint to the zero address");
   // We know if the first token in the batch doesn't exist, the other ones don't as well, because of serial ordering.
   require(!_exists(startTokenId), "ERC721A: token already minted");
   require(quantity <= maxBatchSize, "ERC721A: quantity to mint too high");

   _beforeTokenTransfers(address(0), to, startTokenId, quantity);

   AddressData memory addressData = _addressData[to];
   _addressData[to] = AddressData(
     addressData.balance + uint128(quantity),
     addressData.numberMinted + uint128(quantity)
   );
   _ownerships[startTokenId] = TokenOwnership(to, uint64(block.timestamp));

   uint256 updatedIndex = startTokenId;

   for (uint256 i = 0; i < quantity; i++) {
     emit Transfer(address(0), to, updatedIndex);
     require(
       _checkOnERC721Received(address(0), to, updatedIndex, _data),
       "ERC721A: transfer to non ERC721Receiver implementer"
     );
     updatedIndex++;
   }

   currentIndex = updatedIndex;
   _afterTokenTransfers(address(0), to, startTokenId, quantity);
 }

 /**
  * @dev Transfers `tokenId` from `from` to `to`.
  *
  * 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
 ) private {
   TokenOwnership memory prevOwnership = ownershipOf(tokenId);

   bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
     getApproved(tokenId) == _msgSender() ||
     isApprovedForAll(prevOwnership.addr, _msgSender()));

   require(
     isApprovedOrOwner,
     "ERC721A: transfer caller is not owner nor approved"
   );

   require(
     prevOwnership.addr == from,
     "ERC721A: transfer from incorrect owner"
   );
   require(to != address(0), "ERC721A: transfer to the zero address");

   _beforeTokenTransfers(from, to, tokenId, 1);

   // Clear approvals from the previous owner
   _approve(address(0), tokenId, prevOwnership.addr);

   _addressData[from].balance -= 1;
   _addressData[to].balance += 1;
   _ownerships[tokenId] = TokenOwnership(to, uint64(block.timestamp));

   // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
   // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
   uint256 nextTokenId = tokenId + 1;
   if (_ownerships[nextTokenId].addr == address(0)) {
     if (_exists(nextTokenId)) {
       _ownerships[nextTokenId] = TokenOwnership(
         prevOwnership.addr,
         prevOwnership.startTimestamp
       );
     }
   }

   emit Transfer(from, to, tokenId);
   _afterTokenTransfers(from, to, tokenId, 1);
 }

 /**
  * @dev Approve `to` to operate on `tokenId`
  *
  * Emits a {Approval} event.
  */
 function _approve(
   address to,
   uint256 tokenId,
   address owner
 ) private {
   _tokenApprovals[tokenId] = to;
   emit Approval(owner, to, tokenId);
 }

 uint256 public nextOwnerToExplicitlySet = 0;

 /**
  * @dev Explicitly set `owners` to eliminate loops in future calls of ownerOf().
  */
 function _setOwnersExplicit(uint256 quantity) internal {
   uint256 oldNextOwnerToSet = nextOwnerToExplicitlySet;
   require(quantity > 0, "quantity must be nonzero");
   uint256 endIndex = oldNextOwnerToSet + quantity - 1;
   if (endIndex > collectionSize - 1) {
     endIndex = collectionSize - 1;
   }
   // We know if the last one in the group exists, all in the group exist, due to serial ordering.
   require(_exists(endIndex), "not enough minted yet for this cleanup");
   for (uint256 i = oldNextOwnerToSet; i <= endIndex; i++) {
     if (_ownerships[i].addr == address(0)) {
       TokenOwnership memory ownership = ownershipOf(i);
       _ownerships[i] = TokenOwnership(
         ownership.addr,
         ownership.startTimestamp
       );
     }
   }
   nextOwnerToExplicitlySet = endIndex + 1;
 }

 /**
  * @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("ERC721A: transfer to non ERC721Receiver implementer");
       } else {
         assembly {
           revert(add(32, reason), mload(reason))
         }
       }
     }
   } else {
     return true;
   }
 }

 /**
  * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
  *
  * startTokenId - the first token id to be transferred
  * quantity - the amount to be transferred
  *
  * 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`.
  */
 function _beforeTokenTransfers(
   address from,
   address to,
   uint256 startTokenId,
   uint256 quantity
 ) internal virtual {}

 /**
  * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
  * minting.
  *
  * startTokenId - the first token id to be transferred
  * quantity - the amount to be transferred
  *
  * Calling conditions:
  *
  * - when `from` and `to` are both non-zero.
  * - `from` and `to` are never both zero.
  */
 function _afterTokenTransfers(
   address from,
   address to,
   uint256 startTokenId,
   uint256 quantity
 ) internal virtual {}
}

/// @title HachiNFT
/// @notice A contract for pixelnauts in the starlink ecosystem
contract HachiNFT is Ownable, ERC721A, ReentrancyGuard {
    using   Strings for uint256;

    uint256 public maxSupply = 1000;
    uint256 public mintStartTime;
    string private _baseTokenURI;
    bool public onPublicSale = false;
    constructor (string memory _pendingURI, uint256 _mintStartTime) ERC721A("HachiNFT", "HACHINFT", maxSupply, maxSupply) {
        _baseTokenURI = _pendingURI;
        mintStartTime = _mintStartTime;
    }

    modifier callerIsUser() {
      require(tx.origin == msg.sender, "The caller is another contract");
      _;
    }

    function mint(uint256 _mintAmount) external payable callerIsUser{
      uint256 supply = totalSupply();
      require(block.timestamp > mintStartTime, "Mint Not started");
      require(_mintAmount > 0);
      require(supply + _mintAmount <= maxSupply, "Total supply exceed");
      require(_msgSender() == owner(), "Only owner can mint");

      _safeMint(msg.sender, _mintAmount);

    }

    function _baseURI() internal view virtual override returns (string memory) {
      return _baseTokenURI;
    }

    function refundIfOver(uint256 price) private {
      require(msg.value >= price, "Need to send more ETH.");
      if (msg.value > price) {
        payable(msg.sender).transfer(msg.value - price);
      }
    }

    function setBaseURI(string calldata baseURI) external onlyOwner {
      _baseTokenURI = baseURI;
    }

    function withdrawMoney() external onlyOwner nonReentrant {
      (bool success, ) = msg.sender.call{value: address(this).balance}("");
      require(success, "Transfer failed.");
    }
    
    function setMintStartTime(uint256 _mintStartTime) external onlyOwner {
        mintStartTime = _mintStartTime;
    }

    function setPubliscSale() external onlyOwner {
          onPublicSale = true;
    } 

    function setOwnersExplicit(uint256 quantity) external onlyOwner nonReentrant {
    _setOwnersExplicit(quantity);
    }

    function numberMinted(address owner) public view returns (uint256) {
      return _numberMinted(owner);
    }

    function getOwnershipData(uint256 tokenId)
      external
      view
      returns (TokenOwnership memory)
    {
      return ownershipOf(tokenId);
    }    
}