// File: /D/Work/Projects/Blockchain/Smart contracts/niox-staking-contract/contracts/StakingRewardsFactory.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "./IStakingRewards.sol";
import "./RewardsDistributionRecipient.sol";
import "./KeeperCompatibleInterface.sol";

contract StakingRewards is
  IStakingRewards,
  RewardsDistributionRecipient,
  ReentrancyGuard,
  KeeperCompatibleInterface
{
  using SafeMath for uint256;
  using SafeERC20 for IERC20;

  /* ========== STATE VARIABLES ========== */

  IERC20 public rewardsToken;
  IERC20 public stakingToken;
  uint256 public periodFinish = 0;
  uint256 public rewardRate = 0;
  uint256 public lastUpdateTime;
  uint256 public rewardPerTokenStored;

  mapping(address => uint256) public userRewardPerTokenPaid;
  mapping(address => uint256) public rewards;
  mapping(address => uint256) public _lockingTimeStamp;
  mapping(address => address) public checkUser;
  address[] public userList;

  uint256 private _actualtotalSupply; //  actual total amount staked
  uint256 private _totalSupply; // weight total Stake amount according to tier

  mapping(address => uint256) private _balances; // weight Stake amount
  mapping(address => uint256) private _actualbalances; // actual amount staked

  mapping(address => uint256) private _userLockPeriod; // allow unstake after 3 months from firstStake timestamp
  mapping(address => uint256) private _userRewardLockPeriod; // claim reward every 3 months

  uint256 public lastTimeStamp;

  /**
   * Public counter variable
   */
  uint256 public counter;

  uint256 public interval;

  /* ========== CONSTRUCTOR ========== */

  constructor(
    address _rewardsDistribution,
    address _rewardsToken,
    address _stakingToken
  ) {
    rewardsToken = IERC20(_rewardsToken);
    stakingToken = IERC20(_stakingToken);
    rewardsDistribution = _rewardsDistribution;

    interval = 864000;         // 10 day check interval
    lastTimeStamp = block.timestamp;

    counter = 0;
  }

  /* ========== VIEWS ========== */
  function userLockPeriod() external view override returns (uint256) {
    return _userLockPeriod[msg.sender];
  }

  function userRewardLockPeriod() external view override returns (uint256) {
    return _userRewardLockPeriod[msg.sender];
  }

  function totalSupply() external view override returns (uint256) {
    return _totalSupply;
  }

  function balanceOf(address account) external view override returns (uint256) {
    return _balances[account];
  }

  function actualTotalSupply() external view returns (uint256) {
    return _actualtotalSupply;
  }

  function actualBalanceOf(address account) external view returns (uint256) {
    return _actualbalances[account];
  }

  function lastTimeRewardApplicable() public view override returns (uint256) {
    return Math.min(block.timestamp, periodFinish);
  }

  function rewardPerToken() public view override returns (uint256) {
    if (_totalSupply == 0) {
      return rewardPerTokenStored;
    }
    return
      rewardPerTokenStored.add(
        lastTimeRewardApplicable()
          .sub(lastUpdateTime)
          .mul(rewardRate)
          .mul(1e18)
          .div(_totalSupply)
      );
  }

  function earned(address account) public view override returns (uint256) {
    return
      _balances[account]
        .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))
        .div(1e18)
        .add(rewards[account]);
  }

  /* ========== MUTATIVE FUNCTIONS ========== */

  function stake(uint256 amount)
    external
    override
    nonReentrant
    updateReward(msg.sender)
  {
    require(amount > 0, "Cannot stake 0");

    _updateBalance(msg.sender, amount, true);

    stakingToken.safeTransferFrom(msg.sender, address(this), amount);

    // update at inital stake
    if (_userLockPeriod[msg.sender] < 1) {
      _userLockPeriod[msg.sender] = block.timestamp + 90 days; // for withdraw locking
      _userRewardLockPeriod[msg.sender] = block.timestamp + 90 days; // for reward locking
    }

    emit Staked(msg.sender, amount);
  }

  function stakeComponding(address uaddress)
    internal
    nonReentrant
    updateReward(uaddress)
  {
    uint256 rewardAmt = earned(uaddress);
    require(rewardAmt > 0, "Cannot stake 0");
    if (earned(uaddress) > 0) {
      _updateBalance(uaddress, rewardAmt, true);

      // stakingToken.safeTransferFrom(uaddress, address(this), amount);

      // update at inital stake
      if (_userLockPeriod[uaddress] < 1) {
        _userLockPeriod[uaddress] = block.timestamp + 90 days; // for withdraw locking
        _userRewardLockPeriod[uaddress] = block.timestamp + 90 days; // for reward locking
      }

      rewards[uaddress] = 0; // setting user reward to zero since its added to stake
      emit RewardPaid(uaddress, rewardAmt);

      emit Staked(uaddress, rewardAmt);
    }
  }

  function stakeTransferWithBalance(
    uint256 amount,
    address useraddress,
    uint256 lockingPeriod
  ) external nonReentrant updateReward(useraddress) {
    require(amount > 0, "Cannot stake 0");
    require(_balances[useraddress] <= 0, "Already staked by user");

    _updateBalance(useraddress, amount, true);

    _lockingTimeStamp[useraddress] = lockingPeriod; // setting user locking ts

    stakingToken.safeTransferFrom(msg.sender, address(this), amount);
    emit Staked(useraddress, amount);
  }

  function withdraw(uint256 amount)
    public
    override
    nonReentrant
    updateReward(msg.sender)
  {
    require(amount > 0, "Cannot withdraw 0");
    require(
      block.timestamp > _userLockPeriod[msg.sender],
      "Cannot withdraw before 6 month from inital stake"
    );
    require(
      block.timestamp >= _lockingTimeStamp[msg.sender],
      "Unable to withdraw in locking period"
    );

    _updateBalance(msg.sender, amount, false);

    stakingToken.safeTransfer(msg.sender, amount);
    emit Withdrawn(msg.sender, amount);
  }

  function _updateBalance(
    address userAddress,
    uint256 amount,
    bool isAdd
  ) internal {
    if (isAdd) {
      _actualtotalSupply = _actualtotalSupply.add(amount);
      _actualbalances[userAddress] = _actualbalances[userAddress].add(amount);
    } else {
      _actualtotalSupply = _actualtotalSupply.sub(amount);
      _actualbalances[userAddress] = _actualbalances[userAddress].sub(amount);
    }

    uint256 yield;

    if (_actualbalances[userAddress] >= 3000000000) {
      yield = 100;
    } else if (
      _actualbalances[userAddress] >= 1500000000 &&
      _actualbalances[userAddress] < 3000000000
    ) {
      yield = 75;
    } else if (
      _actualbalances[userAddress] >= 500000000 &&
      _actualbalances[userAddress] < 1500000000
    ) {
      yield = 63;
    } else if (_actualbalances[userAddress] < 500000000) {
      yield = 50;
    }

    uint256 newBalance = _actualbalances[userAddress].mul(yield) / 100;

    if (isAdd) {
      uint256 changedBalance = newBalance.sub(_balances[userAddress]);
      _totalSupply = _totalSupply.add(changedBalance);
    } else {
      uint256 changedBalance = _balances[userAddress].sub(newBalance);
      _totalSupply = _totalSupply.sub(changedBalance);
    }

    _balances[userAddress] = newBalance;
  }

  function getReward() public override nonReentrant updateReward(msg.sender) {
    uint256 reward = rewards[msg.sender];
    require(
      block.timestamp > _userRewardLockPeriod[msg.sender],
      "Cannot withdraw before locking reward period"
    );
    if (reward > 0) {
      rewards[msg.sender] = 0;
      rewardsToken.safeTransfer(msg.sender, reward);
      _userRewardLockPeriod[msg.sender] = block.timestamp + 10 minutes; // reward lock timestamp
      emit RewardPaid(msg.sender, reward);
    }
  }

  function enrollComponding() public nonReentrant {
    require(_balances[msg.sender] > 0, "Not a staker");
    require(
      checkUser[msg.sender] != msg.sender,
      "Already added in compounding"
    );

    checkUser[msg.sender] = msg.sender;
    userList.push(msg.sender);
  }

  function leaveComponding() public nonReentrant {
    require(_balances[msg.sender] > 0, "Not a staker");
    require(
      checkUser[msg.sender] == msg.sender,
      "Already added in compounding"
    );

    address[] memory tempUserList = userList;
    for (uint256 i = 0; i < tempUserList.length; i++) {
      if (tempUserList[i] == msg.sender) {
        tempUserList[i] = tempUserList[tempUserList.length - 1];
        checkUser[msg.sender] = address(0);
        assembly {
          mstore(tempUserList, sub(mload(tempUserList), 1))
        }
        break;
      }
    }

    userList = tempUserList;
  }

  function exit() external override {
    withdraw(_actualbalances[msg.sender]);
    getReward();
  }

  function checkUpkeep(bytes calldata checkData)
    external
    view
    override
    returns (bool upkeepNeeded, bytes memory performData)
  {
    upkeepNeeded = (block.timestamp - lastTimeStamp) > interval;

    // We don't use the checkData in this example
    // checkData was defined when the Upkeep was registered
    performData = checkData;
  }

  function performUpkeep(bytes calldata performData) external override {
    require(
      (block.timestamp - lastTimeStamp) > interval,
      "Auto compound interval not reached"
    );

    lastTimeStamp = block.timestamp;
    counter = counter + 1;

    address[] memory tempUserList = userList;
    uint256 currentRewardPerToken = rewardPerToken();

    for (uint256 i = 0; i < tempUserList.length; i++) {
      address user = tempUserList[i];

      if (
        rewards[user] != 0 ||
        (_balances[user] != 0 &&
          currentRewardPerToken != userRewardPerTokenPaid[user])
      ) {
        stakeComponding(tempUserList[i]);
      }
    }
    // We don't use the performData in this example
    // performData is generated by the Keeper's call to your `checkUpkeep` function
    performData;
  }

  /* ========== RESTRICTED FUNCTIONS ========== */

  function notifyRewardAmount(uint256 reward, uint256 rewardsDuration)
    external
    override
    onlyRewardsDistribution
    updateReward(address(0))
  {
    require(
      block.timestamp.add(rewardsDuration) >= periodFinish,
      "Cannot reduce existing period"
    );

    if (block.timestamp >= periodFinish) {
      rewardRate = reward.div(rewardsDuration);
    } else {
      uint256 remaining = periodFinish.sub(block.timestamp);
      uint256 leftover = remaining.mul(rewardRate);
      rewardRate = reward.add(leftover).div(rewardsDuration);
    }

    // Ensure the provided reward amount is not more than the balance in the contract.
    // This keeps the reward rate in the right range, preventing overflows due to
    // very high values of rewardRate in the earned and rewardsPerToken functions;
    // Reward + leftover must be less than 2^256 / 10^18 to avoid overflow.
    uint256 balance = rewardsToken.balanceOf(address(this));
    require(
      rewardRate <= balance.div(rewardsDuration),
      "Provided reward too high"
    );

    lastUpdateTime = block.timestamp;
    periodFinish = block.timestamp.add(rewardsDuration);
    emit RewardAdded(reward, periodFinish);
  }

  /* ========== MODIFIERS ========== */

  modifier updateReward(address account) {
    rewardPerTokenStored = rewardPerToken();
    lastUpdateTime = lastTimeRewardApplicable();
    if (account != address(0)) {
      rewards[account] = earned(account);
      userRewardPerTokenPaid[account] = rewardPerTokenStored;
    }
    _;
  }

  /* ========== EVENTS ========== */

  event RewardAdded(uint256 reward, uint256 periodFinish);
  event Staked(address indexed user, uint256 amount);
  event Withdrawn(address indexed user, uint256 amount);
  event RewardPaid(address indexed user, uint256 reward);
}

interface IUniswapV2ERC20 {
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}

contract StakingRewardsFactory is Ownable {
  // immutables
  address public rewardsToken;
  uint256 public stakingRewardsGenesis;

  // the staking tokens for which the rewards contract has been deployed
  address[] public stakingTokens;

  // info about rewards for a particular staking token
  struct StakingRewardsInfo {
    address stakingRewards;
    uint256 rewardAmount;
    uint256 duration;
  }

  // rewards info by staking token
  mapping(address => StakingRewardsInfo)
    public stakingRewardsInfoByStakingToken;

  constructor(address _rewardsToken, uint256 _stakingRewardsGenesis) Ownable() {
    require(
      _stakingRewardsGenesis >= block.timestamp,
      "StakingRewardsFactory::constructor: genesis too soon"
    );

    rewardsToken = _rewardsToken;
    stakingRewardsGenesis = _stakingRewardsGenesis;
  }

  ///// permissioned functions

  // deploy a staking reward contract for the staking token, and store the reward amount
  // the reward will be distributed to the staking reward contract no sooner than the genesis
  function deploy(
    address stakingToken,
    uint256 rewardAmount,
    uint256 rewardsDuration
  ) public onlyOwner {
    StakingRewardsInfo storage info = stakingRewardsInfoByStakingToken[
      stakingToken
    ];
    require(
      info.stakingRewards == address(0),
      "StakingRewardsFactory::deploy: already deployed"
    );

    info.stakingRewards = address(
      new StakingRewards(
        /*_rewardsDistribution=*/
        address(this),
        rewardsToken,
        stakingToken
      )
    );
    info.rewardAmount = rewardAmount;
    info.duration = rewardsDuration;
    stakingTokens.push(stakingToken);
  }

  function update(
    address stakingToken,
    uint256 rewardAmount,
    uint256 rewardsDuration
  ) public onlyOwner {
    StakingRewardsInfo storage info = stakingRewardsInfoByStakingToken[
      stakingToken
    ];
    require(
      info.stakingRewards != address(0),
      "StakingRewardsFactory::update: not deployed"
    );

    info.rewardAmount = rewardAmount;
    info.duration = rewardsDuration;
  }

  ///// permissionless functions

  // call notifyRewardAmount for all staking tokens.
  function notifyRewardAmounts() public {
    require(
      stakingTokens.length > 0,
      "StakingRewardsFactory::notifyRewardAmounts: called before any deploys"
    );
    for (uint256 i = 0; i < stakingTokens.length; i++) {
      notifyRewardAmount(stakingTokens[i]);
    }
  }

  // notify reward amount for an individual staking token.
  // this is a fallback in case the notifyRewardAmounts costs too much gas to call for all contracts
  function notifyRewardAmount(address stakingToken) public {
    require(
      block.timestamp >= stakingRewardsGenesis,
      "StakingRewardsFactory::notifyRewardAmount: not ready"
    );

    StakingRewardsInfo storage info = stakingRewardsInfoByStakingToken[
      stakingToken
    ];
    require(
      info.stakingRewards != address(0),
      "StakingRewardsFactory::notifyRewardAmount: not deployed"
    );

    if (info.rewardAmount > 0 && info.duration > 0) {
      uint256 rewardAmount = info.rewardAmount;
      uint256 duration = info.duration;
      info.rewardAmount = 0;
      info.duration = 0;

      require(
        IERC20(rewardsToken).transfer(info.stakingRewards, rewardAmount),
        "StakingRewardsFactory::notifyRewardAmount: transfer failed"
      );
      StakingRewards(info.stakingRewards).notifyRewardAmount(
        rewardAmount,
        duration
      );
    }
  }

  function pullExtraTokens(address token, uint256 amount) external onlyOwner {
    IERC20(token).transfer(msg.sender, amount);
  }
}

// File: @openzeppelin/contracts/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT

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 no longer needed starting with Solidity 0.8. 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 substraction 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;
        }
    }
}

// File: @openzeppelin/contracts/utils/math/Math.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a / b + (a % b == 0 ? 0 : 1);
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

    /**
     * @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);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.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 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));
        }
    }

    /**
     * @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: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT

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 make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: /D/Work/Projects/Blockchain/Smart contracts/niox-staking-contract/contracts/RewardsDistributionRecipient.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

abstract contract RewardsDistributionRecipient {
  address public rewardsDistribution;

  function notifyRewardAmount(uint256 reward, uint256 duration)
    external
    virtual;

  modifier onlyRewardsDistribution() {
    require(
      msg.sender == rewardsDistribution,
      "Caller is not RewardsDistribution contract"
    );
    _;
  }
}

// File: /D/Work/Projects/Blockchain/Smart contracts/niox-staking-contract/contracts/KeeperCompatibleInterface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface KeeperCompatibleInterface {
  function checkUpkeep(bytes calldata checkData)
    external
    view
    returns (bool upkeepNeeded, bytes memory performData);

  function performUpkeep(bytes calldata performData) external;
}

// File: /D/Work/Projects/Blockchain/Smart contracts/niox-staking-contract/contracts/IStakingRewards.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IStakingRewards {
  // Views
  function lastTimeRewardApplicable() external view returns (uint256);

  function rewardPerToken() external view returns (uint256);

  function earned(address account) external view returns (uint256);

  function totalSupply() external view returns (uint256);

  function balanceOf(address account) external view returns (uint256);

  function userLockPeriod() external view returns (uint256);

  function userRewardLockPeriod() external view returns (uint256);

  // Mutative

  function stake(uint256 amount) external;

  function withdraw(uint256 amount) external;

  function getReward() external;

  function exit() external;
}