// Sources flattened with hardhat v2.10.0 https://hardhat.org

// File @openzeppelin/contracts/utils/Context.sol@v4.7.0
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}


// File @openzeppelin/contracts/access/Ownable.sol@v4.7.0
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// File @openzeppelin/contracts/security/ReentrancyGuard.sol@v4.7.0
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}


// File @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol@v4.7.0
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}


// File @openzeppelin/contracts/utils/introspection/IERC165.sol@v4.7.0
// 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@v4.7.0
// OpenZeppelin Contracts (last updated v4.7.0) (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: 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 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 @openzeppelin/contracts/token/ERC20/IERC20.sol@v4.7.0
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}


// File @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol@v4.7.0
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}


// File @openzeppelin/contracts/utils/Address.sol@v4.7.0
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}


// File @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol@v4.7.0
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;



/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 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 SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 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
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 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'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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(IERC20 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, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}


// File contracts/NekoProfitShares.sol

// SPDX-License-Identifier: MIT
/// @author Mr D 
/// @title NEKO ProfitShares
pragma solidity >=0.8.11;
contract NekoProfitShares is Ownable, ReentrancyGuard, IERC721Receiver {
    using SafeERC20 for IERC20;
    
    IERC20 public token;
    IERC721 public nftContract;

    /* @dev team wallet should be a multi-sig wallet, used to transfer 
    ETH out of the contract for a migration, or EOL of the contract */
    address public teamWallet;

    // global flag to set staking and depositing active
    bool public isActive;

    // flag to turn off only deposits
    bool public depositsActive;


    // total points to allocate rewards 
    uint256 public totalSharePoints;

    uint256 private lockDuration = 14 days;

    struct UserLock {
        uint256 tokenAmount; // total amount they currently have locked
        uint256 claimedAmount; // total amount they have withdrawn
        uint256 startTime; // start of the lock
        uint256 endTime; // when the lock ends
    }

    struct UserNftLock {
        uint256 nftId; // nft id they have staked
        uint256 amount; // amount they have locked
        uint256 startTime; // start of the lock
        uint256 endTime; // when the lock ends
    }

    struct NftInfo {
        uint256 lockDuration; // how long this nft needs is locked
        uint256 shareMultiplier;  // multiply users shares by this number 1x = 10
        uint256 lockedNfts; // how many nfts are currently locked for this ID
        bool isDisabled; // so we can hide ones we don't want
    }

    mapping(address => UserLock) public userLocks;
    mapping(address => UserNftLock) public userNftLocks;
    
    NftInfo public nftInfo;
    mapping(address => uint256) public currentMultiplier;

    mapping(address => uint256) public sharePoints;

    uint256 public constant MAX_MULTIPLIER = 30; // 3x

    
    //Multiplier to add some accuracy to profitPerShare
    uint256 private constant DistributionMultiplier = 2**64;
    
    //profit for each share a holder holds, a share equals a decimal.
    uint256 public profitPerShare;

    //the total reward distributed through the vault, for tracking purposes
    uint256 public totalShareRewards;
    
    //the total payout through the vault, for tracking purposes
    uint256 public totalPayouts;
   
    //Mapping of the already paid out(or missed) shares of each staker
    mapping(address => uint256) private alreadyPaidShares;
    
    //Mapping of shares that are reserved for payout
    mapping(address => uint256) private toBePaid;


    event Locked(address indexed account, uint256 unlock );
    event WithdrawTokens(address indexed account, uint256 amount);
    event NftLocked(address indexed account, uint256 nftId, uint256 unlock);

    event ClaimNative(address claimAddress, uint256 amount);
    event NftUnLocked(address indexed account, uint256 nftId);

    constructor (
        IERC20 _token,
        IERC721 _nftContract,
        address  _teamWallet
    ) {     
        token = _token;
        nftContract = _nftContract;
        teamWallet = _teamWallet;
    }

    function setToken(IERC20 _token) public onlyOwner {
        token = _token;
    }


    function setActive(bool _isActive) public onlyOwner {
        isActive = _isActive;
    }

    function setDepositsActive(bool _depositsActive) public onlyOwner {
        depositsActive = _depositsActive;
    }

    function setLockDuration(uint256 _lockDuration) public onlyOwner {
        lockDuration = _lockDuration;
    }

    function setNftContract( IERC721 _nftContract ) public onlyOwner {
        nftContract = _nftContract;      
    }

    function setNftInfo(
        uint256 _lockDuration, 
        uint256 _shareMultiplier) public onlyOwner {
        
        require(_shareMultiplier <= MAX_MULTIPLIER, 'Multiplier too high');

        nftInfo.lockDuration = _lockDuration;
        nftInfo.shareMultiplier = _shareMultiplier; 

    }

    function setNftDisabled(bool _isDisabled) public onlyOwner {
        nftInfo.isDisabled = _isDisabled;        
    }

    function lock(uint256 _amount) public nonReentrant {
        require(isActive && depositsActive,'Not active');
        require(token.balanceOf(msg.sender) >= _amount, 'Not enough tokens');

        userLocks[msg.sender].tokenAmount = userLocks[msg.sender].tokenAmount + _amount;
        userLocks[msg.sender].startTime = block.timestamp; 
        userLocks[msg.sender].endTime = block.timestamp + lockDuration; 
        

        // move the tokens
        token.safeTransferFrom(address(msg.sender), address(this), _amount);

        // multiply existing shares by the multiplier 
        uint256 shares = _amount; 

        if(currentMultiplier[msg.sender] > 0) {
          shares = (_amount * currentMultiplier[msg.sender])/10;
        }

         // give the shares
        _addShares(msg.sender,shares);

        emit Locked( msg.sender,userLocks[msg.sender].endTime );

    }

    function claimLock(uint256 _amount) public nonReentrant {
        require(isActive,'Not active');
        require(userLocks[msg.sender].endTime <= block.timestamp,'Tokens Locked');
        require(userLocks[msg.sender].tokenAmount > 0 && userLocks[msg.sender].tokenAmount >= _amount, 'Not enough tokens Locked');

        userLocks[msg.sender].claimedAmount = userLocks[msg.sender].claimedAmount + _amount;
        userLocks[msg.sender].tokenAmount = userLocks[msg.sender].tokenAmount - _amount;

        // multiply existing shares by the multiplier 
        uint256 shares = _amount; 

        if(currentMultiplier[msg.sender] > 0) {
          shares = (_amount * currentMultiplier[msg.sender])/10;
        }

        // remove the shares
        _removeShares(msg.sender, shares);

        // move the tokens
        token.safeTransfer(address(msg.sender), _amount);
        emit WithdrawTokens(msg.sender, _amount);
        
    }

    // locks an NFT for the amount of time and give shares
    function lockNft(uint256 _nftId) public nonReentrant {
        require(
            isActive &&
            depositsActive &&
            nftInfo.shareMultiplier > 0  && 
            !nftInfo.isDisabled && 
            nftContract.ownerOf(_nftId) == msg.sender &&
            userNftLocks[msg.sender].startTime == 0, "Can't Lock");

        userNftLocks[msg.sender].nftId = _nftId;
        userNftLocks[msg.sender].startTime = block.timestamp; 
        userNftLocks[msg.sender].endTime = block.timestamp + nftInfo.lockDuration; 
        userNftLocks[msg.sender].amount = userNftLocks[msg.sender].amount + 1; 
        
        // update the locked count
        nftInfo.lockedNfts = nftInfo.lockedNfts + 1;

        // assing the multiplier
        currentMultiplier[msg.sender] = nftInfo.shareMultiplier;

        uint256 currentShares = getShares(msg.sender); 
        // multiply existing shares by the multiplier and give them the difference
        uint256 shares = ((currentShares * nftInfo.shareMultiplier)/10) - currentShares;

        _addShares(msg.sender, shares);

        // send the NFT
        nftContract.safeTransferFrom( msg.sender, address(this), _nftId);

        emit NftLocked( msg.sender, _nftId, userNftLocks[msg.sender].endTime);

    }

    // unlocks and claims an NFT if allowed and removes the shares
    function unLockNft(uint256 _nftId) public nonReentrant {
        require(isActive && userNftLocks[msg.sender].amount > 0, 'Not Locked');
        require(block.timestamp >= userNftLocks[msg.sender].endTime, 'Still Locked');
 
        uint256 currentShares = getShares(msg.sender); 
        uint256 shares;
        if(currentMultiplier[msg.sender] > 0) {
            // divide existing shares by the multiplier and remove the difference
            shares = currentShares - ((currentShares*10)/currentMultiplier[msg.sender]);
        }
        
        // reset the multiplier
        currentMultiplier[msg.sender] = 0;

        // remove the shares
        _removeShares(msg.sender, shares);

        uint256 amount = userNftLocks[msg.sender].amount;
        delete userNftLocks[msg.sender];

        // update the locked count
        nftInfo.lockedNfts = nftInfo.lockedNfts - amount;
        
        // send the NFT
        nftContract.safeTransferFrom(  address(this), msg.sender, _nftId);

        emit NftUnLocked( msg.sender, _nftId);
    }

    //gets shares of an address
    function getShares(address _addr) public view returns(uint256){
        return (sharePoints[_addr]);
    }

    //gets locks of an address
    function getLocked(address _addr) public view returns(uint256){
        return userLocks[_addr].tokenAmount;
    }

    //Returns the not paid out dividends of an address in wei
    function getDividends(address _addr) public view returns (uint256){
        return _getDividendsOf(_addr) + toBePaid[_addr];
    }

    function claimNative() public nonReentrant {
        require(isActive,'Not active');
           
        uint256 amount = getDividends(msg.sender);
        require(amount!=0,"=0"); 
        //Substracts the amount from the dividends
        _updateClaimedDividends(msg.sender, amount);
        totalPayouts+=amount;
        (bool sent,) =msg.sender.call{value: (amount)}("");
        require(sent,"withdraw failed");
        emit ClaimNative(msg.sender,amount);

    }

    //adds Token to balances, adds new Native to the toBePaid mapping and resets staking
    function _addShares(address _addr, uint256 _amount) private {
        // the new amount of points
        uint256 newAmount = sharePoints[_addr] + _amount;

        // update the total points
        totalSharePoints+=_amount;

        //gets the payout before the change
        uint256 payment = _getDividendsOf(_addr);

        //resets dividends to 0 for newAmount
        alreadyPaidShares[_addr] = profitPerShare * newAmount;
        //adds dividends to the toBePaid mapping
        toBePaid[_addr]+=payment; 
        //sets newBalance
        sharePoints[_addr]=newAmount;
    }

    //removes shares, adds Native to the toBePaid mapping and resets staking
    function _removeShares(address _addr, uint256 _amount) private {
        //the amount of token after transfer
        uint256 newAmount=sharePoints[_addr] - _amount;
        totalSharePoints -= _amount;

        //gets the payout before the change
        uint256 payment =_getDividendsOf(_addr);
        //sets newBalance
        sharePoints[_addr]=newAmount;
        //resets dividendss to 0 for newAmount
        alreadyPaidShares[_addr] = profitPerShare * sharePoints[_addr];
        //adds dividendss to the toBePaid mapping
        toBePaid[_addr] += payment; 
    }

    //gets the dividends of an address that aren't in the toBePaid mapping 
    function _getDividendsOf(address _addr) private view returns (uint256) {
        uint256 fullPayout = profitPerShare * sharePoints[_addr];
        //if excluded from staking or some error return 0
        if(fullPayout<=alreadyPaidShares[_addr]) return 0;
        return (fullPayout - alreadyPaidShares[_addr])/DistributionMultiplier;
    }

    //adjust the profit share with the new amount
    function _updateProfitPerShare(uint256 _amount) private {

        totalShareRewards += _amount;
        if (totalSharePoints > 0) {
            //Increases profit per share based on current total shares
            profitPerShare += ((_amount * DistributionMultiplier)/totalSharePoints);
        }
    }

    //Substracts the amount from dividends, fails if amount exceeds dividends
    function _updateClaimedDividends(address _addr,uint256 _amount) private {

        uint256 newAmount = _getDividendsOf(_addr);

        //sets payout mapping to current amount
        alreadyPaidShares[_addr] = profitPerShare * sharePoints[_addr];
        //the amount to be paid 
        toBePaid[_addr]+=newAmount;
        toBePaid[_addr]-=_amount;
    }

    event OnProfitSharesReceive(address indexed sender, uint256 amount);
    receive() external payable {

        if(msg.value > 0 && totalSharePoints > 0){
            _updateProfitPerShare(msg.value);
        }

        emit OnProfitSharesReceive(msg.sender, msg.value);
    }

    event TeamWalletChange(address oldTeamWallet, address newTeamWallet);
    function setTeamWallet(address _teamWallet) public {
        require(msg.sender == teamWallet,'Not allowed');

        address prevWallet = teamWallet;
        teamWallet = _teamWallet;

        emit TeamWalletChange(prevWallet, _teamWallet);
    }

    // pull all the ETH out of the contract to the owner, needed for migrations/emergencies/EOL 
    // the team wallet should be set to a multi-sig wallet
    event AdminEthWithdraw(address account, uint256 amount);
    function withdrawETH() public {
        require(msg.sender == teamWallet,'Not allowed');
        uint256 amount = address(this).balance;
         (bool sent,) =address(owner()).call{value: (amount)}("");

        require(sent,"withdraw failed");
        emit AdminEthWithdraw(msg.sender, amount);
    }

    function onERC721Received(address operator, address, uint256, bytes calldata) external view returns(bytes4) {
        require(operator == address(this), "can not directly transfer");
        return bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"));
    }
}