// SPDX-License-Identifier: MIT
pragma solidity ^0.8.11;

import "@thirdweb-dev/contracts/base/Staking721Base.sol";

contract Fooling_Around is Staking721Base {
    
    uint256 private nextConditionId;

    constructor(
        uint256 _timeUnit,
        uint256 _rewardsPerUnitTime,
        address _stakingToken,
        address _rewardToken,
        address _nativeTokenWrapper
    )
        Staking721Base(
            _timeUnit,
            _rewardsPerUnitTime,
            _stakingToken,
            _rewardToken,
            _nativeTokenWrapper
        )
    {}

    function returnStakersSnapshot() 
        public 
        view 
        returns(address[] memory)    
    {
        return stakersArray;
    }

    function returnTokensSnaphot()
        public
        view
        virtual
        returns (uint256[] memory)
    {
        address[] memory _stakersArray = stakersArray;
        uint256 stakersCount = _stakersArray.length;
        uint256[] memory stakersSnapshot = new uint256[](stakersCount);
        uint256 tokensStakedPosition = 0;

        for (uint256 i = 0; i < stakersCount; i++) {
            uint256[] memory _indexedTokens = indexedTokens;
            bool[] memory _isStakerToken = new bool[](_indexedTokens.length);
            uint256 indexedTokenCount = _indexedTokens.length;
            
            uint256 stakerTokenCount = 0;
            for (uint256 j = 0; j < indexedTokenCount; j++) {
                _isStakerToken[j] = stakerAddress[_indexedTokens[j]] == stakersArray[i];
                if (_isStakerToken[j]) stakerTokenCount += 1;
            }
            stakersSnapshot[tokensStakedPosition] = stakerTokenCount;
            tokensStakedPosition += 1;

        }
        
        return stakersSnapshot;
    }

    function returnRewardsSnapshot()
        public
        view
        virtual
        returns (uint256[] memory)
    {
        address[] memory _stakersArray = stakersArray;
        uint256 stakersCount = _stakersArray.length;
        uint256[] memory rewardsSnapshot = new uint256[](stakersCount);

        for (uint256 i = 0; i < stakersCount; i++) {            
            rewardsSnapshot[i] = _availableRewards(stakersArray[i]);
        }

        return rewardsSnapshot;
    }

}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./interface/IContractMetadata.sol";

/**
 *  @title   Contract Metadata
 *  @notice  Thirdweb's `ContractMetadata` is a contract extension for any base contracts. It lets you set a metadata URI
 *           for you contract.
 *           Additionally, `ContractMetadata` is necessary for NFT contracts that want royalties to get distributed on OpenSea.
 */

abstract contract ContractMetadata is IContractMetadata {
    /// @notice Returns the contract metadata URI.
    string public override contractURI;

    /**
     *  @notice         Lets a contract admin set the URI for contract-level metadata.
     *  @dev            Caller should be authorized to setup contractURI, e.g. contract admin.
     *                  See {_canSetContractURI}.
     *                  Emits {ContractURIUpdated Event}.
     *
     *  @param _uri     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     */
    function setContractURI(string memory _uri) external override {
        if (!_canSetContractURI()) {
            revert("Not authorized");
        }

        _setupContractURI(_uri);
    }

    /// @dev Lets a contract admin set the URI for contract-level metadata.
    function _setupContractURI(string memory _uri) internal {
        string memory prevURI = contractURI;
        contractURI = _uri;

        emit ContractURIUpdated(prevURI, _uri);
    }

    /// @dev Returns whether contract metadata can be set in the given execution context.
    function _canSetContractURI() internal view virtual returns (bool);
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

// Helper interfaces
import { IWETH } from "../interfaces/IWETH.sol";

import "../openzeppelin-presets/token/ERC20/utils/SafeERC20.sol";

library CurrencyTransferLib {
    using SafeERC20 for IERC20;

    /// @dev The address interpreted as native token of the chain.
    address public constant NATIVE_TOKEN = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

    /// @dev Transfers a given amount of currency.
    function transferCurrency(
        address _currency,
        address _from,
        address _to,
        uint256 _amount
    ) internal {
        if (_amount == 0) {
            return;
        }

        if (_currency == NATIVE_TOKEN) {
            safeTransferNativeToken(_to, _amount);
        } else {
            safeTransferERC20(_currency, _from, _to, _amount);
        }
    }

    /// @dev Transfers a given amount of currency. (With native token wrapping)
    function transferCurrencyWithWrapper(
        address _currency,
        address _from,
        address _to,
        uint256 _amount,
        address _nativeTokenWrapper
    ) internal {
        if (_amount == 0) {
            return;
        }

        if (_currency == NATIVE_TOKEN) {
            if (_from == address(this)) {
                // withdraw from weth then transfer withdrawn native token to recipient
                IWETH(_nativeTokenWrapper).withdraw(_amount);
                safeTransferNativeTokenWithWrapper(_to, _amount, _nativeTokenWrapper);
            } else if (_to == address(this)) {
                // store native currency in weth
                require(_amount == msg.value, "msg.value != amount");
                IWETH(_nativeTokenWrapper).deposit{ value: _amount }();
            } else {
                safeTransferNativeTokenWithWrapper(_to, _amount, _nativeTokenWrapper);
            }
        } else {
            safeTransferERC20(_currency, _from, _to, _amount);
        }
    }

    /// @dev Transfer `amount` of ERC20 token from `from` to `to`.
    function safeTransferERC20(
        address _currency,
        address _from,
        address _to,
        uint256 _amount
    ) internal {
        if (_from == _to) {
            return;
        }

        if (_from == address(this)) {
            IERC20(_currency).safeTransfer(_to, _amount);
        } else {
            IERC20(_currency).safeTransferFrom(_from, _to, _amount);
        }
    }

    /// @dev Transfers `amount` of native token to `to`.
    function safeTransferNativeToken(address to, uint256 value) internal {
        // solhint-disable avoid-low-level-calls
        // slither-disable-next-line low-level-calls
        (bool success, ) = to.call{ value: value }("");
        require(success, "native token transfer failed");
    }

    /// @dev Transfers `amount` of native token to `to`. (With native token wrapping)
    function safeTransferNativeTokenWithWrapper(
        address to,
        uint256 value,
        address _nativeTokenWrapper
    ) internal {
        // solhint-disable avoid-low-level-calls
        // slither-disable-next-line low-level-calls
        (bool success, ) = to.call{ value: value }("");
        if (!success) {
            IWETH(_nativeTokenWrapper).deposit{ value: value }();
            IERC20(_nativeTokenWrapper).safeTransfer(to, value);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./interface/IERC165.sol";

/**
 * @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;
    }
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 *  Thirdweb's `ContractMetadata` is a contract extension for any base contracts. It lets you set a metadata URI
 *  for you contract.
 *
 *  Additionally, `ContractMetadata` is necessary for NFT contracts that want royalties to get distributed on OpenSea.
 */

interface IContractMetadata {
    /// @dev Returns the metadata URI of the contract.
    function contractURI() external view returns (string memory);

    /**
     *  @dev Sets contract URI for the storefront-level metadata of the contract.
     *       Only module admin can call this function.
     */
    function setContractURI(string calldata _uri) external;

    /// @dev Emitted when the contract URI is updated.
    event ContractURIUpdated(string prevURI, string newURI);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * [EIP](https://eips.ethereum.org/EIPS/eip-165).
 *
 * 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
     * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
     * 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);
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 {
    /**
     * @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);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address);

    /**
     * @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);

    /**
     * @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;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Multicall.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides a function to batch together multiple calls in a single external call.
 *
 * _Available since v4.1._
 */
interface IMulticall {
    /**
     * @dev Receives and executes a batch of function calls on this contract.
     */
    function multicall(bytes[] calldata data) external returns (bytes[] memory results);
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 *  Thirdweb's `Ownable` is a contract extension to be used with any base contract. It exposes functions for setting and reading
 *  who the 'owner' of the inheriting smart contract is, and lets the inheriting contract perform conditional logic that uses
 *  information about who the contract's owner is.
 */

interface IOwnable {
    /// @dev Returns the owner of the contract.
    function owner() external view returns (address);

    /// @dev Lets a module admin set a new owner for the contract. The new owner must be a module admin.
    function setOwner(address _newOwner) external;

    /// @dev Emitted when a new Owner is set.
    event OwnerUpdated(address indexed prevOwner, address indexed newOwner);
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.11;

interface IStaking721 {
    /// @dev Emitted when a set of token-ids are staked.
    event TokensStaked(address indexed staker, uint256[] indexed tokenIds);

    /// @dev Emitted when a set of staked token-ids are withdrawn.
    event TokensWithdrawn(address indexed staker, uint256[] indexed tokenIds);

    /// @dev Emitted when a staker claims staking rewards.
    event RewardsClaimed(address indexed staker, uint256 rewardAmount);

    /// @dev Emitted when contract admin updates timeUnit.
    event UpdatedTimeUnit(uint256 oldTimeUnit, uint256 newTimeUnit);

    /// @dev Emitted when contract admin updates rewardsPerUnitTime.
    event UpdatedRewardsPerUnitTime(uint256 oldRewardsPerUnitTime, uint256 newRewardsPerUnitTime);

    /**
     *  @notice Staker Info.
     *
     *  @param amountStaked             Total number of tokens staked by the staker.
     *
     *  @param timeOfLastUpdate         Last reward-update timestamp.
     *
     *  @param unclaimedRewards         Rewards accumulated but not claimed by user yet.
     *
     *  @param conditionIdOflastUpdate  Condition-Id when rewards were last updated for user.
     */
    struct Staker {
        uint256 amountStaked;
        uint256 timeOfLastUpdate;
        uint256 unclaimedRewards;
        uint256 conditionIdOflastUpdate;
    }

    /**
     *  @notice Staking Condition.
     *
     *  @param timeUnit           Unit of time specified in number of seconds. Can be set as 1 seconds, 1 days, 1 hours, etc.
     *
     *  @param rewardsPerUnitTime Rewards accumulated per unit of time.
     *
     *  @param startTimestamp     Condition start timestamp.
     *
     *  @param endTimestamp       Condition end timestamp.
     */
    struct StakingCondition {
        uint256 timeUnit;
        uint256 rewardsPerUnitTime;
        uint256 startTimestamp;
        uint256 endTimestamp;
    }

    /**
     *  @notice Stake ERC721 Tokens.
     *
     *  @param tokenIds    List of tokens to stake.
     */
    function stake(uint256[] calldata tokenIds) external;

    /**
     *  @notice Withdraw staked tokens.
     *
     *  @param tokenIds    List of tokens to withdraw.
     */
    function withdraw(uint256[] calldata tokenIds) external;

    /**
     *  @notice Claim accumulated rewards.
     */
    function claimRewards() external;

    /**
     *  @notice View amount staked and total rewards for a user.
     *
     *  @param staker    Address for which to calculated rewards.
     */
    function getStakeInfo(address staker) external view returns (uint256[] memory _tokensStaked, uint256 _rewards);
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

interface IWETH {
    function deposit() external payable;

    function withdraw(uint256 amount) external;

    function transfer(address to, uint256 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Multicall.sol)

pragma solidity ^0.8.0;

import "../lib/TWAddress.sol";
import "./interface/IMulticall.sol";

/**
 * @dev Provides a function to batch together multiple calls in a single external call.
 *
 * _Available since v4.1._
 */
contract Multicall is IMulticall {
    /**
     *  @notice Receives and executes a batch of function calls on this contract.
     *  @dev Receives and executes a batch of function calls on this contract.
     *
     *  @param data The bytes data that makes up the batch of function calls to execute.
     *  @return results The bytes data that makes up the result of the batch of function calls executed.
     */
    function multicall(bytes[] calldata data) external virtual override returns (bytes[] memory results) {
        results = new bytes[](data.length);
        for (uint256 i = 0; i < data.length; i++) {
            results[i] = TWAddress.functionDelegateCall(address(this), data[i]);
        }
        return results;
    }
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./interface/IOwnable.sol";

/**
 *  @title   Ownable
 *  @notice  Thirdweb's `Ownable` is a contract extension to be used with any base contract. It exposes functions for setting and reading
 *           who the 'owner' of the inheriting smart contract is, and lets the inheriting contract perform conditional logic that uses
 *           information about who the contract's owner is.
 */

abstract contract Ownable is IOwnable {
    /// @dev Owner of the contract (purpose: OpenSea compatibility)
    address private _owner;

    /// @dev Reverts if caller is not the owner.
    modifier onlyOwner() {
        if (msg.sender != _owner) {
            revert("Not authorized");
        }
        _;
    }

    /**
     *  @notice Returns the owner of the contract.
     */
    function owner() public view override returns (address) {
        return _owner;
    }

    /**
     *  @notice Lets an authorized wallet set a new owner for the contract.
     *  @param _newOwner The address to set as the new owner of the contract.
     */
    function setOwner(address _newOwner) external override {
        if (!_canSetOwner()) {
            revert("Not authorized");
        }
        _setupOwner(_newOwner);
    }

    /// @dev Lets a contract admin set a new owner for the contract. The new owner must be a contract admin.
    function _setupOwner(address _newOwner) internal {
        address _prevOwner = _owner;
        _owner = _newOwner;

        emit OwnerUpdated(_prevOwner, _newOwner);
    }

    /// @dev Returns whether owner can be set in the given execution context.
    function _canSetOwner() internal view virtual returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

abstract contract ReentrancyGuard {
    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.
     */
    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;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../../../../eip/interface/IERC20.sol";
import "../../../../lib/TWAddress.sol";

/**
 * @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 TWAddress 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));
        }
    }

    /**
     * @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");
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // 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 (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @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) {
        return a + b;
    }

    /**
     * @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 a - b;
    }

    /**
     * @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) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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 a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.11;

import "../openzeppelin-presets/security/ReentrancyGuard.sol";
import "../openzeppelin-presets/utils/math/SafeMath.sol";
import "../eip/interface/IERC721.sol";

import "./interface/IStaking721.sol";

abstract contract Staking721 is ReentrancyGuard, IStaking721 {
    /*///////////////////////////////////////////////////////////////
                            State variables / Mappings
    //////////////////////////////////////////////////////////////*/

    ///@dev Address of ERC721 NFT contract -- staked tokens belong to this contract.
    address public stakingToken;

    ///@dev List of token-ids ever staked.
    uint256[] public indexedTokens;

    /// @dev List of accounts that have staked their NFTs.
    address[] public stakersArray;

    /// @dev Flag to check direct transfers of staking tokens.
    uint8 internal isStaking = 1;

    ///@dev Next staking condition Id. Tracks number of conditon updates so far.
    uint256 private nextConditionId;

    ///@dev Mapping from token-id to whether it is indexed or not.
    mapping(uint256 => bool) public isIndexed;

    ///@dev Mapping from staker address to Staker struct. See {struct IStaking721.Staker}.
    mapping(address => Staker) public stakers;

    /// @dev Mapping from staked token-id to staker address.
    mapping(uint256 => address) public stakerAddress;

    ///@dev Mapping from condition Id to staking condition. See {struct IStaking721.StakingCondition}
    mapping(uint256 => StakingCondition) private stakingConditions;

    constructor(address _stakingToken) ReentrancyGuard() {
        require(address(_stakingToken) != address(0), "collection address 0");
        stakingToken = _stakingToken;
    }

    /*///////////////////////////////////////////////////////////////
                        External/Public Functions
    //////////////////////////////////////////////////////////////*/

    /**
     *  @notice    Stake ERC721 Tokens.
     *
     *  @dev       See {_stake}. Override that to implement custom logic.
     *
     *  @param _tokenIds    List of tokens to stake.
     */
    function stake(uint256[] calldata _tokenIds) external nonReentrant {
        _stake(_tokenIds);
    }

    /**
     *  @notice    Withdraw staked tokens.
     *
     *  @dev       See {_withdraw}. Override that to implement custom logic.
     *
     *  @param _tokenIds    List of tokens to withdraw.
     */
    function withdraw(uint256[] calldata _tokenIds) external nonReentrant {
        _withdraw(_tokenIds);
    }

    /**
     *  @notice    Claim accumulated rewards.
     *
     *  @dev       See {_claimRewards}. Override that to implement custom logic.
     *             See {_calculateRewards} for reward-calculation logic.
     */
    function claimRewards() external nonReentrant {
        _claimRewards();
    }

    /**
     *  @notice  Set time unit. Set as a number of seconds.
     *           Could be specified as -- x * 1 hours, x * 1 days, etc.
     *
     *  @dev     Only admin/authorized-account can call it.
     *
     *
     *  @param _timeUnit    New time unit.
     */
    function setTimeUnit(uint256 _timeUnit) external virtual {
        if (!_canSetStakeConditions()) {
            revert("Not authorized");
        }

        StakingCondition memory condition = stakingConditions[nextConditionId - 1];
        require(_timeUnit != condition.timeUnit, "Time-unit unchanged.");

        _setStakingCondition(_timeUnit, condition.rewardsPerUnitTime);

        emit UpdatedTimeUnit(condition.timeUnit, _timeUnit);
    }

    /**
     *  @notice  Set rewards per unit of time.
     *           Interpreted as x rewards per second/per day/etc based on time-unit.
     *
     *  @dev     Only admin/authorized-account can call it.
     *
     *
     *  @param _rewardsPerUnitTime    New rewards per unit time.
     */
    function setRewardsPerUnitTime(uint256 _rewardsPerUnitTime) external virtual {
        if (!_canSetStakeConditions()) {
            revert("Not authorized");
        }

        StakingCondition memory condition = stakingConditions[nextConditionId - 1];
        require(_rewardsPerUnitTime != condition.rewardsPerUnitTime, "Reward unchanged.");

        _setStakingCondition(condition.timeUnit, _rewardsPerUnitTime);

        emit UpdatedRewardsPerUnitTime(condition.rewardsPerUnitTime, _rewardsPerUnitTime);
    }

    /**
     *  @notice View amount staked and total rewards for a user.
     *
     *  @param _staker          Address for which to calculated rewards.
     *  @return _tokensStaked   List of token-ids staked by staker.
     *  @return _rewards        Available reward amount.
     */
    function getStakeInfo(address _staker)
        external
        view
        virtual
        returns (uint256[] memory _tokensStaked, uint256 _rewards)
    {
        uint256[] memory _indexedTokens = indexedTokens;
        bool[] memory _isStakerToken = new bool[](_indexedTokens.length);
        uint256 indexedTokenCount = _indexedTokens.length;
        uint256 stakerTokenCount = 0;

        for (uint256 i = 0; i < indexedTokenCount; i++) {
            _isStakerToken[i] = stakerAddress[_indexedTokens[i]] == _staker;
            if (_isStakerToken[i]) stakerTokenCount += 1;
        }

        _tokensStaked = new uint256[](stakerTokenCount);
        uint256 count = 0;
        for (uint256 i = 0; i < indexedTokenCount; i++) {
            if (_isStakerToken[i]) {
                _tokensStaked[count] = _indexedTokens[i];
                count += 1;
            }
        }

        _rewards = _availableRewards(_staker);
    }

    function getTimeUnit() public view returns (uint256 _timeUnit) {
        _timeUnit = stakingConditions[nextConditionId - 1].timeUnit;
    }

    function getRewardsPerUnitTime() public view returns (uint256 _rewardsPerUnitTime) {
        _rewardsPerUnitTime = stakingConditions[nextConditionId - 1].rewardsPerUnitTime;
    }

    /*///////////////////////////////////////////////////////////////
                            Internal Functions
    //////////////////////////////////////////////////////////////*/

    /// @dev Staking logic. Override to add custom logic.
    function _stake(uint256[] calldata _tokenIds) internal virtual {
        uint256 len = _tokenIds.length;
        require(len != 0, "Staking 0 tokens");

        address _stakingToken = stakingToken;

        if (stakers[_stakeMsgSender()].amountStaked > 0) {
            _updateUnclaimedRewardsForStaker(_stakeMsgSender());
        } else {
            stakersArray.push(_stakeMsgSender());
            stakers[_stakeMsgSender()].timeOfLastUpdate = block.timestamp;
            stakers[_stakeMsgSender()].conditionIdOflastUpdate = nextConditionId - 1;
        }
        for (uint256 i = 0; i < len; ++i) {
            require(
                IERC721(_stakingToken).ownerOf(_tokenIds[i]) == _stakeMsgSender() &&
                    (IERC721(_stakingToken).getApproved(_tokenIds[i]) == address(this) ||
                        IERC721(_stakingToken).isApprovedForAll(_stakeMsgSender(), address(this))),
                "Not owned or approved"
            );

            isStaking = 2;
            IERC721(_stakingToken).safeTransferFrom(_stakeMsgSender(), address(this), _tokenIds[i]);
            isStaking = 1;

            stakerAddress[_tokenIds[i]] = _stakeMsgSender();

            if (!isIndexed[_tokenIds[i]]) {
                isIndexed[_tokenIds[i]] = true;
                indexedTokens.push(_tokenIds[i]);
            }
        }
        stakers[_stakeMsgSender()].amountStaked += len;

        emit TokensStaked(_stakeMsgSender(), _tokenIds);
    }

    /// @dev Withdraw logic. Override to add custom logic.
    function _withdraw(uint256[] calldata _tokenIds) internal virtual {
        uint256 _amountStaked = stakers[_stakeMsgSender()].amountStaked;
        uint256 len = _tokenIds.length;
        require(len != 0, "Withdrawing 0 tokens");
        require(_amountStaked >= len, "Withdrawing more than staked");

        address _stakingToken = stakingToken;

        _updateUnclaimedRewardsForStaker(_stakeMsgSender());

        if (_amountStaked == len) {
            address[] memory _stakersArray = stakersArray;
            for (uint256 i = 0; i < _stakersArray.length; ++i) {
                if (_stakersArray[i] == _stakeMsgSender()) {
                    stakersArray[i] = _stakersArray[_stakersArray.length - 1];
                    stakersArray.pop();
                    break;
                }
            }
        }
        stakers[_stakeMsgSender()].amountStaked -= len;

        for (uint256 i = 0; i < len; ++i) {
            require(stakerAddress[_tokenIds[i]] == _stakeMsgSender(), "Not staker");
            stakerAddress[_tokenIds[i]] = address(0);
            IERC721(_stakingToken).safeTransferFrom(address(this), _stakeMsgSender(), _tokenIds[i]);
        }

        emit TokensWithdrawn(_stakeMsgSender(), _tokenIds);
    }

    /// @dev Logic for claiming rewards. Override to add custom logic.
    function _claimRewards() internal virtual {
        uint256 rewards = stakers[_stakeMsgSender()].unclaimedRewards + _calculateRewards(_stakeMsgSender());

        require(rewards != 0, "No rewards");

        stakers[_stakeMsgSender()].timeOfLastUpdate = block.timestamp;
        stakers[_stakeMsgSender()].unclaimedRewards = 0;
        stakers[_stakeMsgSender()].conditionIdOflastUpdate = nextConditionId - 1;

        _mintRewards(_stakeMsgSender(), rewards);

        emit RewardsClaimed(_stakeMsgSender(), rewards);
    }

    /// @dev View available rewards for a user.
    function _availableRewards(address _user) internal view virtual returns (uint256 _rewards) {
        if (stakers[_user].amountStaked == 0) {
            _rewards = stakers[_user].unclaimedRewards;
        } else {
            _rewards = stakers[_user].unclaimedRewards + _calculateRewards(_user);
        }
    }

    /// @dev Update unclaimed rewards for a users. Called for every state change for a user.
    function _updateUnclaimedRewardsForStaker(address _staker) internal virtual {
        uint256 rewards = _calculateRewards(_staker);
        stakers[_staker].unclaimedRewards += rewards;
        stakers[_staker].timeOfLastUpdate = block.timestamp;
        stakers[_staker].conditionIdOflastUpdate = nextConditionId - 1;
    }

    /// @dev Set staking conditions.
    function _setStakingCondition(uint256 _timeUnit, uint256 _rewardsPerUnitTime) internal virtual {
        require(_timeUnit != 0, "time-unit can't be 0");
        uint256 conditionId = nextConditionId;
        nextConditionId += 1;

        stakingConditions[conditionId] = StakingCondition({
            timeUnit: _timeUnit,
            rewardsPerUnitTime: _rewardsPerUnitTime,
            startTimestamp: block.timestamp,
            endTimestamp: 0
        });

        if (conditionId > 0) {
            stakingConditions[conditionId - 1].endTimestamp = block.timestamp;
        }
    }

    /// @dev Calculate rewards for a staker.
    function _calculateRewards(address _staker) internal view virtual returns (uint256 _rewards) {
        Staker memory staker = stakers[_staker];

        uint256 _stakerConditionId = staker.conditionIdOflastUpdate;
        uint256 _nextConditionId = nextConditionId;

        for (uint256 i = _stakerConditionId; i < _nextConditionId; i += 1) {
            StakingCondition memory condition = stakingConditions[i];

            uint256 startTime = i != _stakerConditionId ? condition.startTimestamp : staker.timeOfLastUpdate;
            uint256 endTime = condition.endTimestamp != 0 ? condition.endTimestamp : block.timestamp;

            (bool noOverflowProduct, uint256 rewardsProduct) = SafeMath.tryMul(
                (endTime - startTime) * staker.amountStaked,
                condition.rewardsPerUnitTime
            );
            (bool noOverflowSum, uint256 rewardsSum) = SafeMath.tryAdd(_rewards, rewardsProduct / condition.timeUnit);

            _rewards = noOverflowProduct && noOverflowSum ? rewardsSum : _rewards;
        }
    }

    /*////////////////////////////////////////////////////////////////////
        Optional hooks that can be implemented in the derived contract
    ///////////////////////////////////////////////////////////////////*/

    /// @dev Exposes the ability to override the msg sender -- support ERC2771.
    function _stakeMsgSender() internal virtual returns (address) {
        return msg.sender;
    }

    /*///////////////////////////////////////////////////////////////
        Virtual functions to be implemented in derived contract
    //////////////////////////////////////////////////////////////*/

    /**
     *  @notice View total rewards available in the staking contract.
     *
     */
    function getRewardTokenBalance() external view virtual returns (uint256 _rewardsAvailableInContract);

    /**
     *  @dev    Mint/Transfer ERC20 rewards to the staker. Must override.
     *
     *  @param _staker    Address for which to calculated rewards.
     *  @param _rewards   Amount of tokens to be given out as reward.
     *
     *  For example, override as below to mint ERC20 rewards:
     *
     * ```
     *  function _mintRewards(address _staker, uint256 _rewards) internal override {
     *
     *      TokenERC20(rewardTokenAddress).mintTo(_staker, _rewards);
     *
     *  }
     * ```
     */
    function _mintRewards(address _staker, uint256 _rewards) internal virtual;

    /**
     *  @dev    Returns whether staking restrictions can be set in given execution context.
     *          Must override.
     *
     *
     *  For example, override as below to restrict access to admin:
     *
     * ```
     *  function _canSetStakeConditions() internal override {
     *
     *      return msg.sender == adminAddress;
     *
     *  }
     * ```
     */
    function _canSetStakeConditions() internal view virtual returns (bool);
}

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "../extension/ContractMetadata.sol";
import "../extension/Multicall.sol";
import "../extension/Ownable.sol";
import "../extension/Staking721.sol";

import "../eip/ERC165.sol";
import "../eip/interface/IERC20.sol";
import "../eip/interface/IERC721Receiver.sol";

import { CurrencyTransferLib } from "../lib/CurrencyTransferLib.sol";

/**
 *
 *  EXTENSION: Staking721
 *
 *  The `Staking721Base` smart contract implements NFT staking mechanism.
 *  Allows users to stake their ERC-721 NFTs and earn rewards in form of ERC-20 tokens.
 *
 *  Following features and implementation setup must be noted:
 *
 *      - ERC-721 NFTs from only one NFT collection can be staked.
 *
 *      - Contract admin can choose to give out rewards by either transferring or minting the rewardToken,
 *        which is an ERC20 token. See {_mintRewards}.
 *
 *      - To implement custom logic for staking, reward calculation, etc. corresponding functions can be
 *        overridden from the extension `Staking721`.
 *
 *      - Ownership of the contract, with the ability to restrict certain functions to
 *        only be called by the contract's owner.
 *
 *      - Multicall capability to perform multiple actions atomically.
 *
 */

/// note: This contract is provided as a base contract.
//        This is to support a variety of use-cases that can be build on top of this base.
//
//        Additional functionality such as deposit functions, reward-minting, etc.
//        must be implemented by the deployer of this contract, as needed for their use-case.

contract Staking721Base is ContractMetadata, Multicall, Ownable, Staking721, ERC165, IERC721Receiver {
    /// @dev ERC20 Reward Token address. See {_mintRewards} below.
    address public rewardToken;

    /// @dev The address of the native token wrapper contract.
    address public nativeTokenWrapper;

    /// @dev Total amount of reward tokens in the contract.
    uint256 private rewardTokenBalance;

    constructor(
        uint256 _timeUnit,
        uint256 _rewardsPerUnitTime,
        address _stakingToken,
        address _rewardToken,
        address _nativeTokenWrapper
    ) Staking721(_stakingToken) {
        _setupOwner(msg.sender);
        _setStakingCondition(_timeUnit, _rewardsPerUnitTime);

        rewardToken = _rewardToken;
        nativeTokenWrapper = _nativeTokenWrapper;
    }

    /// @dev Lets the contract receive ether to unwrap native tokens.
    receive() external payable virtual {
        require(msg.sender == nativeTokenWrapper, "caller not native token wrapper.");
    }

    /// @dev Admin deposits reward tokens.
    function depositRewardTokens(uint256 _amount) external payable nonReentrant {
        _depositRewardTokens(_amount); // override this for custom logic.
    }

    /// @dev Admin can withdraw excess reward tokens.
    function withdrawRewardTokens(uint256 _amount) external nonReentrant {
        _withdrawRewardTokens(_amount); // override this for custom logic.
    }

    /// @notice View total rewards available in the staking contract.
    function getRewardTokenBalance() external view virtual override returns (uint256) {
        return rewardTokenBalance;
    }

    /*///////////////////////////////////////////////////////////////
                        ERC 165 / 721 logic
    //////////////////////////////////////////////////////////////*/

    function onERC721Received(
        address,
        address,
        uint256,
        bytes calldata
    ) external view virtual override returns (bytes4) {
        require(isStaking == 2, "Direct transfer");
        return this.onERC721Received.selector;
    }

    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC721Receiver).interfaceId || super.supportsInterface(interfaceId);
    }

    /*//////////////////////////////////////////////////////////////
                        Minting logic
    //////////////////////////////////////////////////////////////*/

    /**
     *  @dev    Mint ERC20 rewards to the staker. Override for custom logic.
     *
     *  @param _staker    Address for which to calculated rewards.
     *  @param _rewards   Amount of tokens to be given out as reward.
     *
     */
    function _mintRewards(address _staker, uint256 _rewards) internal virtual override {
        require(_rewards <= rewardTokenBalance, "Not enough reward tokens");
        rewardTokenBalance -= _rewards;
        CurrencyTransferLib.transferCurrencyWithWrapper(
            rewardToken,
            address(this),
            _staker,
            _rewards,
            nativeTokenWrapper
        );
    }

    /*//////////////////////////////////////////////////////////////
                        Other Internal functions
    //////////////////////////////////////////////////////////////*/

    /// @dev Admin deposits reward tokens -- override for custom logic.
    function _depositRewardTokens(uint256 _amount) internal virtual {
        require(msg.sender == owner(), "Not authorized");

        address _rewardToken = rewardToken == CurrencyTransferLib.NATIVE_TOKEN ? nativeTokenWrapper : rewardToken;

        uint256 balanceBefore = IERC20(_rewardToken).balanceOf(address(this));
        CurrencyTransferLib.transferCurrencyWithWrapper(
            rewardToken,
            msg.sender,
            address(this),
            _amount,
            nativeTokenWrapper
        );
        uint256 actualAmount = IERC20(_rewardToken).balanceOf(address(this)) - balanceBefore;

        rewardTokenBalance += actualAmount;
    }

    /// @dev Admin can withdraw excess reward tokens -- override for custom logic.
    function _withdrawRewardTokens(uint256 _amount) internal virtual {
        require(msg.sender == owner(), "Not authorized");

        // to prevent locking of direct-transferred tokens
        rewardTokenBalance = _amount > rewardTokenBalance ? 0 : rewardTokenBalance - _amount;

        CurrencyTransferLib.transferCurrencyWithWrapper(
            rewardToken,
            address(this),
            msg.sender,
            _amount,
            nativeTokenWrapper
        );
    }

    /// @dev Returns whether staking restrictions can be set in given execution context.
    function _canSetStakeConditions() internal view virtual override returns (bool) {
        return msg.sender == owner();
    }

    /// @dev Returns whether contract metadata can be set in the given execution context.
    function _canSetContractURI() internal view virtual override returns (bool) {
        return msg.sender == owner();
    }

    /// @dev Returns whether owner can be set in the given execution context.
    function _canSetOwner() internal view virtual override returns (bool) {
        return msg.sender == owner();
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library TWAddress {
    /**
     * @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.
     *
     * [EIP1884](https://eips.ethereum.org/EIPS/eip-1884) increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

{
  "compilationTarget": {
    "contracts/Contract.sol": "Fooling_Around"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}