/**
 *
*/

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol


// OpenZeppelin Contracts v4.4.1 (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);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol


// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;


/**
 * @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`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev 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 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: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * 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 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 the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @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);
}

// File: MingStake.sol

//SPDX-License-Identifier: MIT


pragma solidity 0.8.16;


//import "@nomiclabs/buidler/console.sol";

/*
 * @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 GSN 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.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor() {}

    function _msgSender() internal view returns (address payable) {
        return payable(msg.sender);
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        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.
 */
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() {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view 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 onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = 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 onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), 'Ownable: new owner is the zero address');
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, 'SafeMath: addition overflow');

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, 'SafeMath: subtraction overflow');
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, 'SafeMath: multiplication overflow');

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, 'SafeMath: division by zero');
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, 'SafeMath: modulo by zero');
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }

    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint256 y) internal pure returns (uint256 z) {
        if (y > 3) {
            z = y;
            uint256 x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

interface IBEP20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the token decimals.
     */
    function decimals() external view returns (uint8);

    /**
     * @dev Returns the token symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the token name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the bep token owner.
     */
    function getOwner() external view returns (address);

    /**
     * @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);
}

/**
 * @title SafeBEP20
 * @dev Wrappers around BEP20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeBEP20 for IBEP20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeBEP20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(
        IBEP20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IBEP20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IBEP20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IBEP20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            'SafeBEP20: approve from non-zero to non-zero allowance'
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IBEP20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IBEP20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(
            value,
            'SafeBEP20: decreased allowance below zero'
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IBEP20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, 'SafeBEP20: low-level call failed');
        if (returndata.length > 0) {
            // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), 'SafeBEP20: BEP20 operation did not succeed');
        }
    }
}

/**
 * @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) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @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');

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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');
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(
        address target,
        bytes memory data,
        uint256 weiValue,
        string memory errorMessage
    ) private returns (bytes memory) {
        require(isContract(target), 'Address: call to non-contract');

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{value: weiValue}(data);
        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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

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;
    }
}

contract MingStakeTwo is Ownable, ReentrancyGuard {
    using SafeMath for uint256;
    using SafeBEP20 for IBEP20;

    // Info of each user.
    struct UserInfo {
        uint256 amount;     // How many LP tokens the user has provided.
        uint256 boostedAmount;
        uint256 boosts;
        uint256 rewardDebt; // Reward debt. See explanation below.
        uint256 pendingPayout; // track any previously pending payouts from boosts
    }

    // Info of each pool.
    struct PoolInfo {
        IBEP20 lpToken;           // Address of LP token contract.
        uint256 allocPoint;       // How many allocation points assigned to this pool. Tokens to distribute per block.
        uint256 lastRewardTimestamp;  // Last block number that Tokens distribution occurs.
        uint256 accTokensPerShare; // Accumulated Tokens per share, times 1e12. See below.
    }

    IBEP20 public immutable stakingToken;
    IBEP20 public immutable rewardToken;
    IERC721 public immutable nftToken;
    mapping (address => uint256) public holderUnlockTime;

    mapping (address => bool) public _isAuthorized;

    uint256 public totalStaked;
    uint256 public totalBoostedStaked;
    uint256 public apr;
    uint256 public lockDuration;
    uint256 public exitPenaltyPerc;

    uint256 public amountPerBoost;
    uint256 public maxBoostAmount;
    mapping ( address => uint256) public lastWalletBoostTs;
    
    bool public canCompoundOrStakeMore;

    // Info of each pool.
    PoolInfo[] public poolInfo;
    // Info of each user that stakes LP tokens.
    mapping (address => UserInfo) public userInfo;
    // Total allocation points. Must be the sum of all allocation points in all pools.
    uint256 private totalAllocPoint;

    event Deposit(address indexed user, uint256 amount);
    event Withdraw(address indexed user, uint256 amount);
    event Compound(address indexed user);
    event EmergencyWithdraw(address indexed user, uint256 amount);

    constructor(address _nftTokenAddress, address _stakingToken, address _tokenAddress, uint256 _apr, uint256 _lockDurationInDays, uint256 _exitPenaltyPerc, bool _canCompoundOrStakeMore) {
        stakingToken = IBEP20(_stakingToken);
        rewardToken = IBEP20(_tokenAddress);
        nftToken = IERC721(_nftTokenAddress);
        canCompoundOrStakeMore = _canCompoundOrStakeMore;
        _isAuthorized[msg.sender] = true;

        apr = _apr;
        lockDuration = _lockDurationInDays * 1 days;
        exitPenaltyPerc = _exitPenaltyPerc;

        amountPerBoost = 50; // 25% boost per booster
        maxBoostAmount = 6; // 6 boosts allowed

        // staking pool
        poolInfo.push(PoolInfo({
            lpToken: stakingToken,
            allocPoint: 1000,
            lastRewardTimestamp: 99999999999,
            accTokensPerShare: 0
        }));

        totalAllocPoint = 1000;

    }

    modifier onlyAuthorized() {
        require(_isAuthorized[msg.sender], "Not Authorized");
        _;
    }

    function setAuthorization(address account, bool authorized) external onlyOwner {
        _isAuthorized[account] = authorized;
    }

    function stopReward() external onlyOwner {
        updatePool(0);
        apr = 0;
    }

    function startReward() external onlyOwner {
        require(poolInfo[0].lastRewardTimestamp == 99999999999, "Can only start rewards once");
        poolInfo[0].lastRewardTimestamp = block.timestamp;
    }

    // View function to see pending Reward on frontend.
    function pendingReward(address _user) external view returns (uint256) {
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[_user];
        if(pool.lastRewardTimestamp == 99999999999){
            return 0;
        }
        uint256 accTokensPerShare = pool.accTokensPerShare;
        uint256 lpSupply = totalBoostedStaked;
        if (block.timestamp > pool.lastRewardTimestamp && lpSupply != 0) {
            uint256 tokenReward = calculateNewRewards().mul(pool.allocPoint).div(totalAllocPoint);
            accTokensPerShare = accTokensPerShare.add(tokenReward.mul(1e12).div(lpSupply));
        }
        return user.boostedAmount.mul(accTokensPerShare).div(1e12).sub(user.rewardDebt) + user.pendingPayout;
    }

    // Update reward variables of the given pool to be up-to-date.
    function updatePool(uint256 _pid) internal {
        PoolInfo storage pool = poolInfo[_pid];
        if (block.timestamp <= pool.lastRewardTimestamp) {
            return;
        }
        uint256 lpSupply = totalBoostedStaked;
        if (lpSupply == 0) {
            pool.lastRewardTimestamp = block.timestamp;
            return;
        }
        uint256 tokenReward = calculateNewRewards().mul(pool.allocPoint).div(totalAllocPoint);
        pool.accTokensPerShare = pool.accTokensPerShare.add(tokenReward.mul(1e12).div(lpSupply));
        pool.lastRewardTimestamp = block.timestamp;
    }

    // Update reward variables for all pools. Be careful of gas spending!
    function massUpdatePools() public onlyOwner {
        uint256 length = poolInfo.length;
        for (uint256 pid = 0; pid < length; ++pid) {
            updatePool(pid);
        }
    }

    // Stake primary tokens
    function deposit(uint256 _amount) external nonReentrant {
        require(nftToken.balanceOf(msg.sender) > 0, "You must to have NFT");
        if(holderUnlockTime[msg.sender] == 0){
            holderUnlockTime[msg.sender] = block.timestamp + lockDuration;
        }
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[msg.sender];

        if(!canCompoundOrStakeMore && _amount > 0){
            require(user.boostedAmount == 0, "Cannot stake more");
        }

        updatePool(0);
        if (user.boostedAmount > 0) {
            uint256 pending = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12).sub(user.rewardDebt) + user.pendingPayout;
            user.pendingPayout = 0;
            if(pending > 0) {
                require(pending <= rewardsRemaining(), "Cannot withdraw other people's staked tokens.  Contact an admin.");
                rewardToken.safeTransfer(address(msg.sender), pending);
            }
        }
        uint256 amountTransferred = 0;
        if(_amount > 0) {
            totalBoostedStaked -= getWalletBoostedAmount(msg.sender);
            uint256 initialBalance = pool.lpToken.balanceOf(address(this));
            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
            amountTransferred = pool.lpToken.balanceOf(address(this)) - initialBalance;
            user.amount = user.amount.add(amountTransferred);
            totalStaked += amountTransferred;
            totalBoostedStaked += getWalletBoostedAmount(msg.sender);
            user.boostedAmount = getWalletBoostedAmount(msg.sender);
        }
        user.rewardDebt = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12);

        emit Deposit(msg.sender, _amount);
    }

    function compound() external nonReentrant {
        require(canCompoundOrStakeMore, "Cannot compound");
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[msg.sender];

        updatePool(0);
        if (user.boostedAmount > 0) {
            uint256 pending = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12).sub(user.rewardDebt) + user.pendingPayout;
            user.pendingPayout = 0;
            if(pending > 0) {
                require(pending <= rewardsRemaining(), "Cannot withdraw other people's staked tokens.  Contact an admin.");
                totalBoostedStaked -= getWalletBoostedAmount(msg.sender);
                user.amount += pending;
                totalStaked += pending;
                totalBoostedStaked += getWalletBoostedAmount(msg.sender);
                user.boostedAmount = getWalletBoostedAmount(msg.sender);
            }
        }

        user.rewardDebt = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12);
        emit Compound(msg.sender);
    }

    // Withdraw primary tokens from STAKING.

    function withdraw() external nonReentrant {

        require(holderUnlockTime[msg.sender] <= block.timestamp, "May not do normal withdraw early");
        
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[msg.sender];

        uint256 _amount = user.amount;
        updatePool(0);
        uint256 pending = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12).sub(user.rewardDebt) + user.pendingPayout;
        user.pendingPayout = 0;
        if(pending > 0){
            require(pending <= rewardsRemaining(), "Cannot withdraw other people's staked tokens.  Contact an admin.");
            rewardToken.safeTransfer(address(msg.sender), pending);
        }

        if(_amount > 0) {
            totalBoostedStaked -= user.boostedAmount;
            user.boostedAmount = 0;
            user.boosts = 0;
            user.amount = 0;
            totalStaked -= _amount;
            pool.lpToken.safeTransfer(address(msg.sender), _amount);
        }

        user.rewardDebt = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12);
        
        if(user.amount > 0){
            holderUnlockTime[msg.sender] = block.timestamp + lockDuration;
        } else {
            holderUnlockTime[msg.sender] = 0;
        }

        emit Withdraw(msg.sender, _amount);
    }

    // Withdraw without caring about rewards. EMERGENCY ONLY.
    function emergencyWithdraw() external nonReentrant {
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[msg.sender];
        uint256 _amount = user.amount;
        totalBoostedStaked -= user.boostedAmount;
        totalStaked -= _amount;
        // exit penalty for early unstakers, penalty held on contract as rewards.
        if(holderUnlockTime[msg.sender] >= block.timestamp){
            _amount -= _amount * exitPenaltyPerc / 100;
        }
        holderUnlockTime[msg.sender] = 0;
        pool.lpToken.safeTransfer(address(msg.sender), _amount);
        user.amount = 0;
        user.boostedAmount = 0;
        user.boosts = 0;
        user.rewardDebt = 0;
        user.pendingPayout = 0;
        emit EmergencyWithdraw(msg.sender, _amount);
    }

    // Withdraw reward. EMERGENCY ONLY. This allows the owner to migrate rewards to a new staking pool since we are not minting new tokens.
    function emergencyRewardWithdraw(uint256 _amount) external onlyOwner {
        require(_amount <= rewardToken.balanceOf(address(this)) - totalStaked, 'not enough tokens to take out');
        rewardToken.safeTransfer(address(msg.sender), _amount);
    }

    function calculateNewRewards() public view returns (uint256) {
        PoolInfo storage pool = poolInfo[0];
        if(pool.lastRewardTimestamp > block.timestamp){
            return 0;
        }
        return (((block.timestamp - pool.lastRewardTimestamp) * totalBoostedStaked) * apr / 100 / 365 days);
    }

    function rewardsRemaining() public view returns (uint256){
        return rewardToken.balanceOf(address(this)) - totalStaked;
    }

    function updateApr(uint256 newApr) external onlyOwner {
        require(newApr <= 1000, "APR must be below 1000%");
        updatePool(0);
        apr = newApr;
    }

    // only applies for new stakers
    function updateLockDuration(uint256 daysForLock) external onlyOwner {
        require(daysForLock <= 365, "Lock must be 365 days or less.");
        lockDuration = daysForLock * 1 days;
    }

    function updateExitPenalty(uint256 newPenaltyPerc) external onlyOwner {
        require(newPenaltyPerc <= 20, "May not set higher than 20%");
        exitPenaltyPerc = newPenaltyPerc;
    }

    function updateCanCompoundOrStakeMore(bool compoundEnabled) external onlyOwner {
        canCompoundOrStakeMore = compoundEnabled;
    }

    function getWalletBoostedAmount(address wallet) public view returns (uint256){
        UserInfo storage user = userInfo[wallet];
        return user.amount * (100+(user.boosts*amountPerBoost)) / 100;
    }

    function getWalletAPR(address wallet) public view returns (uint256){
        UserInfo storage user = userInfo[wallet];
        return apr * (100+(user.boosts*amountPerBoost)) / 100;
    }

    function addBoost(address wallet) external onlyAuthorized {
        
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[wallet];
        if(user.boosts < maxBoostAmount){
            updatePool(0);
            uint256 pending = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12).sub(user.rewardDebt) + user.pendingPayout;
            user.pendingPayout = pending;
            totalBoostedStaked -= user.boostedAmount;
            user.boosts += 1;
            user.boostedAmount = getWalletBoostedAmount(wallet);
            totalBoostedStaked += user.boostedAmount;
            user.rewardDebt = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12);
            lastWalletBoostTs[wallet] = block.timestamp;
        }
    }

    function removeBoost(address wallet) external onlyAuthorized {
        
        PoolInfo storage pool = poolInfo[0];
        UserInfo storage user = userInfo[wallet];
        if(user.boosts > 0){
            updatePool(0);
            uint256 pending = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12).sub(user.rewardDebt) + user.pendingPayout;
            user.pendingPayout = pending;
            totalBoostedStaked -= user.boostedAmount;
            user.boosts -= 1;
            user.boostedAmount = getWalletBoostedAmount(wallet);
            totalBoostedStaked += user.boostedAmount;
            user.rewardDebt = user.boostedAmount.mul(pool.accTokensPerShare).div(1e12);
        }
        
    }

    function updateBoosters(uint256 newMaxBoostAmount, uint256 newAmountPerBoost) external onlyOwner {
        require(newAmountPerBoost <= 100, "amount per boost too high");
        maxBoostAmount = newMaxBoostAmount;
        amountPerBoost = newAmountPerBoost;
    }
}