diff --git a/contracts/pool/GOFGDAIPool.sol b/contracts/pool/GOFGDAIPool.sol
new file mode 100644
index 0000000..0106433
--- /dev/null
+++ b/contracts/pool/GOFGDAIPool.sol
@@ -0,0 +1,735 @@
+
+// File: @openzeppelin/contracts/math/Math.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @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, so we distribute
+        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
+    }
+}
+
+// File: @openzeppelin/contracts/math/SafeMath.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @dev Wrappers over Solidity's arithmetic operations with added overflow
+ * checks.
+ *
+ * Arithmetic operations in Solidity wrap on overflow. This can easily result
+ * in bugs, because programmers usually assume that an overflow raises an
+ * error, which is the standard behavior in high level programming languages.
+ * `SafeMath` restores this intuition by reverting the transaction when an
+ * operation overflows.
+ *
+ * Using this library instead of the unchecked operations eliminates an entire
+ * class of bugs, so it's recommended to use it always.
+ */
+library SafeMath {
+    /**
+     * @dev Returns the addition of two unsigned integers, reverting on
+     * overflow.
+     *
+     * Counterpart to Solidity's `+` operator.
+     *
+     * Requirements:
+     * - Addition cannot overflow.
+     */
+    function add(uint256 a, uint256 b) internal pure returns (uint256) {
+        uint256 c = a + b;
+        require(c >= a, "SafeMath: addition overflow");
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, reverting on
+     * overflow (when the result is negative).
+     *
+     * Counterpart to Solidity's `-` operator.
+     *
+     * Requirements:
+     * - Subtraction cannot overflow.
+     */
+    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
+        return sub(a, b, "SafeMath: subtraction overflow");
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
+     * overflow (when the result is negative).
+     *
+     * Counterpart to Solidity's `-` operator.
+     *
+     * Requirements:
+     * - Subtraction cannot overflow.
+     *
+     * _Available since v2.4.0._
+     */
+    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
+        require(b <= a, errorMessage);
+        uint256 c = a - b;
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the multiplication of two unsigned integers, reverting on
+     * overflow.
+     *
+     * Counterpart to Solidity's `*` operator.
+     *
+     * Requirements:
+     * - Multiplication cannot overflow.
+     */
+    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
+        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+        // benefit is lost if 'b' is also tested.
+        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
+        if (a == 0) {
+            return 0;
+        }
+
+        uint256 c = a * b;
+        require(c / a == b, "SafeMath: multiplication overflow");
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the integer division of two unsigned integers. Reverts on
+     * division by zero. The result is rounded towards zero.
+     *
+     * Counterpart to Solidity's `/` operator. Note: this function uses a
+     * `revert` opcode (which leaves remaining gas untouched) while Solidity
+     * uses an invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     */
+    function div(uint256 a, uint256 b) internal pure returns (uint256) {
+        return div(a, b, "SafeMath: division by zero");
+    }
+
+    /**
+     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
+     * division by zero. The result is rounded towards zero.
+     *
+     * Counterpart to Solidity's `/` operator. Note: this function uses a
+     * `revert` opcode (which leaves remaining gas untouched) while Solidity
+     * uses an invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     *
+     * _Available since v2.4.0._
+     */
+    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
+        // Solidity only automatically asserts when dividing by 0
+        require(b > 0, errorMessage);
+        uint256 c = a / b;
+        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
+     * Reverts when dividing by zero.
+     *
+     * Counterpart to Solidity's `%` operator. This function uses a `revert`
+     * opcode (which leaves remaining gas untouched) while Solidity uses an
+     * invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     */
+    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
+        return mod(a, b, "SafeMath: modulo by zero");
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
+     * Reverts with custom message when dividing by zero.
+     *
+     * Counterpart to Solidity's `%` operator. This function uses a `revert`
+     * opcode (which leaves remaining gas untouched) while Solidity uses an
+     * invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     *
+     * _Available since v2.4.0._
+     */
+    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
+        require(b != 0, errorMessage);
+        return a % b;
+    }
+}
+
+// File: @openzeppelin/contracts/GSN/Context.sol
+
+pragma solidity 0.5.16;
+
+/*
+ * @dev Provides information about the current execution context, including the
+ * sender of the transaction and its data. While these are generally available
+ * via msg.sender and msg.data, they should not be accessed in such a direct
+ * manner, since when dealing with GSN meta-transactions the account sending and
+ * paying for execution may not be the actual sender (as far as an application
+ * is concerned).
+ *
+ * This contract is only required for intermediate, library-like contracts.
+ */
+contract Context {
+    // Empty internal constructor, to prevent people from mistakenly deploying
+    // an instance of this contract, which should be used via inheritance.
+    constructor () internal { }
+    // solhint-disable-previous-line no-empty-blocks
+
+    function _msgSender() internal view returns (address payable) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view returns (bytes memory) {
+        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
+        return msg.data;
+    }
+}
+
+// File: @openzeppelin/contracts/ownership/Ownable.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @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.
+ *
+ * This module is used through inheritance. It will make available the modifier
+ * `onlyOwner`, which can be applied to your functions to restrict their use to
+ * the owner.
+ */
+contract Ownable is Context {
+    address private _owner;
+
+    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
+
+    /**
+     * @dev Initializes the contract setting the deployer as the initial owner.
+     */
+    constructor () internal {
+        _owner = _msgSender();
+        emit OwnershipTransferred(address(0), _owner);
+    }
+
+    /**
+     * @dev Returns the address of the current owner.
+     */
+    function owner() public view returns (address) {
+        return _owner;
+    }
+
+    /**
+     * @dev Throws if called by any account other than the owner.
+     */
+    modifier onlyOwner() {
+        require(isOwner(), "Ownable: caller is not the owner");
+        _;
+    }
+
+    /**
+     * @dev Returns true if the caller is the current owner.
+     */
+    function isOwner() public view returns (bool) {
+        return _msgSender() == _owner;
+    }
+
+    /**
+     * @dev Leaves the contract without owner. It will not be possible to call
+     * `onlyOwner` functions anymore. Can only be called by the current owner.
+     *
+     * NOTE: Renouncing ownership will leave the contract without an owner,
+     * thereby removing any functionality that is only available to the owner.
+     */
+    function renounceOwnership() public onlyOwner {
+        emit OwnershipTransferred(_owner, address(0));
+        _owner = address(0);
+    }
+
+    /**
+     * @dev Transfers ownership of the contract to a new account (`newOwner`).
+     * Can only be called by the current owner.
+     */
+    function transferOwnership(address newOwner) public onlyOwner {
+        _transferOwnership(newOwner);
+    }
+
+    /**
+     * @dev Transfers ownership of the contract to a new account (`newOwner`).
+     */
+    function _transferOwnership(address newOwner) internal {
+        require(newOwner != address(0), "Ownable: new owner is the zero address");
+        emit OwnershipTransferred(_owner, newOwner);
+        _owner = newOwner;
+    }
+}
+
+// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
+ * the optional functions; to access them see {ERC20Detailed}.
+ */
+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);
+    function mint(address account, uint amount) external;
+
+    /**
+     * @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/utils/Address.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @dev Collection of functions related to the address type
+ */
+library Address {
+    /**
+     * @dev Returns true if `account` is a contract.
+     *
+     * This test is non-exhaustive, and there may be false-negatives: during the
+     * execution of a contract's constructor, its address will be reported as
+     * not containing 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.
+     */
+    function isContract(address account) internal view returns (bool) {
+        // This method relies in extcodesize, which returns 0 for contracts in
+        // construction, since the code is only stored at the end of the
+        // constructor execution.
+
+        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
+        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
+        // for accounts without code, i.e. `keccak256('')`
+        bytes32 codehash;
+        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
+        // solhint-disable-next-line no-inline-assembly
+        assembly { codehash := extcodehash(account) }
+        return (codehash != 0x0 && codehash != accountHash);
+    }
+
+    /**
+     * @dev Converts an `address` into `address payable`. Note that this is
+     * simply a type cast: the actual underlying value is not changed.
+     *
+     * _Available since v2.4.0._
+     */
+    function toPayable(address account) internal pure returns (address payable) {
+        return address(uint160(account));
+    }
+
+    /**
+     * @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].
+     *
+     * _Available since v2.4.0._
+     */
+    function sendValue(address payable recipient, uint256 amount) internal {
+        require(address(this).balance >= amount, "Address: insufficient balance");
+
+        // solhint-disable-next-line avoid-call-value
+        (bool success, ) = recipient.call.value(amount)("");
+        require(success, "Address: unable to send value, recipient may have reverted");
+    }
+}
+
+// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @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 ERC20;` statement to your contract,
+ * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
+ */
+library SafeERC20 {
+    using SafeMath for uint256;
+    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));
+    }
+
+    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'
+        // solhint-disable-next-line max-line-length
+        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).add(value);
+        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
+    }
+
+    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
+        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
+        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
+    }
+
+    /**
+     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
+     * on the return value: the return value is optional (but if data is returned, it must not be false).
+     * @param token The token targeted by the call.
+     * @param data The call data (encoded using abi.encode or one of its variants).
+     */
+    function callOptionalReturn(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.
+
+        // A Solidity high level call has three parts:
+        //  1. The target address is checked to verify it contains contract code
+        //  2. The call itself is made, and success asserted
+        //  3. The return value is decoded, which in turn checks the size of the returned data.
+        // solhint-disable-next-line max-line-length
+        require(address(token).isContract(), "SafeERC20: call to non-contract");
+
+        // solhint-disable-next-line avoid-low-level-calls
+        (bool success, bytes memory returndata) = address(token).call(data);
+        require(success, "SafeERC20: low-level call failed");
+
+        if (returndata.length > 0) { // Return data is optional
+            // solhint-disable-next-line max-line-length
+            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
+        }
+    }
+}
+
+/**
+ * Reward Amount Interface
+ */
+pragma solidity 0.5.16;
+
+contract IRewardDistributionRecipient is Ownable {
+    address rewardDistribution;
+
+    function notifyRewardAmount(uint256 reward) external;
+
+    modifier onlyRewardDistribution() {
+        require(_msgSender() == rewardDistribution, "Caller is not reward distribution");
+        _;
+    }
+
+    function setRewardDistribution(address _rewardDistribution)
+        external
+        onlyOwner
+    {
+        rewardDistribution = _rewardDistribution;
+    }
+}
+
+ /**
+  * Staking Token Wrapper
+  */
+pragma solidity 0.5.16;
+
+contract GOFTokenWrapper {
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
+
+    IERC20 public stakeToken = IERC20(0xd8C89b89BdCac2d6280B5FA80202f9213b37A0F3);
+    
+    uint256 private _totalSupply;
+    mapping(address => uint256) private _balances;
+
+    function totalSupply() public view returns (uint256) {
+        return _totalSupply;
+    }
+
+    function balanceOf(address account) public view returns (uint256) {
+        return _balances[account];
+    }
+
+    function stake(uint256 amount) public {
+        uint256 _before = stakeToken.balanceOf(address(this));
+        stakeToken.safeTransferFrom(msg.sender, address(this), amount);
+        uint256 _after = stakeToken.balanceOf(address(this));
+        uint256 _amount = _after.sub(_before);
+        
+        _totalSupply = _totalSupply.add(_amount);
+        _balances[msg.sender] = _balances[msg.sender].add(_amount);
+    }
+
+    function withdraw(uint256 amount) public {
+        _totalSupply = _totalSupply.sub(amount);
+        _balances[msg.sender] = _balances[msg.sender].sub(amount);
+        stakeToken.safeTransfer(msg.sender, amount);
+    }
+}
+
+/**
+ *  Pool
+ */
+pragma solidity 0.5.16;
+
+contract GOFGDAIPool is GOFTokenWrapper, IRewardDistributionRecipient {
+    
+    IERC20 public gof = IERC20(0x488E0369f9BC5C40C002eA7c1fe4fd01A198801c);
+    uint256 public constant DURATION = 7 days;
+
+    uint256 public constant startTime = 1602676800; //utc+8 2020-10-14 20:00:00
+    uint256 public periodFinish = 0;
+    uint256 public rewardRate = 0;
+    uint256 public lastUpdateTime;
+    uint256 public rewardPerTokenStored = 0;
+    bool private open = true;
+    uint256 private constant _gunit = 1e18;
+    mapping(address => uint256) public userRewardPerTokenPaid; 
+    mapping(address => uint256) public rewards; // Unclaimed rewards
+
+    event RewardAdded(uint256 reward);
+    event Staked(address indexed user, uint256 amount);
+    event Withdrawn(address indexed user, uint256 amount);
+    event RewardPaid(address indexed user, uint256 reward);
+    event SetOpen(bool _open);
+
+    modifier updateReward(address account) {
+        rewardPerTokenStored = rewardPerToken();
+        lastUpdateTime = lastTimeRewardApplicable();
+        if (account != address(0)) {
+            rewards[account] = earned(account);
+            userRewardPerTokenPaid[account] = rewardPerTokenStored;
+        }
+        _;
+    }
+
+    function lastTimeRewardApplicable() public view returns (uint256) {
+        return Math.min(block.timestamp, periodFinish);
+    }
+
+    /**
+     * Calculate the rewards for each token
+     */
+    function rewardPerToken() public view returns (uint256) {
+        if (totalSupply() == 0) {
+            return rewardPerTokenStored;
+        }
+        return
+            rewardPerTokenStored.add(
+                lastTimeRewardApplicable()
+                    .sub(lastUpdateTime)
+                    .mul(rewardRate)
+                    .mul(_gunit)
+                    .div(totalSupply())
+            );
+    }
+
+    function earned(address account) public view returns (uint256) {
+        return
+            balanceOf(account)
+                .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))
+                .div(_gunit)
+                .add(rewards[account]);
+    }
+
+    function stake(uint256 amount) public checkOpen checkStart updateReward(msg.sender){ 
+        require(amount > 0, "Golff-POOL: Cannot stake 0");
+        super.stake(amount);
+        emit Staked(msg.sender, amount);
+    }
+
+    function withdraw(uint256 amount) public checkStart updateReward(msg.sender){
+        require(amount > 0, "Golff-POOL: Cannot withdraw 0");
+        super.withdraw(amount);
+        emit Withdrawn(msg.sender, amount);
+    }
+
+    function exit() external {
+        withdraw(balanceOf(msg.sender));
+        getReward();
+    }
+
+    function getReward() public checkStart updateReward(msg.sender){
+        uint256 reward = earned(msg.sender);
+        if (reward > 0) {
+            rewards[msg.sender] = 0;
+            gof.safeTransfer(msg.sender, reward);
+            emit RewardPaid(msg.sender, reward);
+        }
+    }
+
+    modifier checkStart(){
+        require(block.timestamp > startTime,"Golff-POOL: Not start");
+        _;
+    }
+
+    modifier checkOpen() {
+        require(open, "Golff-POOL: Pool is closed");
+        _;
+    }
+
+    function getPeriodFinish() external view returns (uint256) {
+        return periodFinish;
+    }
+
+    function isOpen() external view returns (bool) {
+        return open;
+    }
+
+    function setOpen(bool _open) external onlyOwner {
+        open = _open;
+        emit SetOpen(_open);
+    }
+
+    function notifyRewardAmount(uint256 reward)
+        external
+        onlyRewardDistribution
+        checkOpen
+        updateReward(address(0)){
+        if (block.timestamp > startTime){
+            if (block.timestamp >= periodFinish) {
+                uint256 period = block.timestamp.sub(startTime).div(DURATION).add(1);
+                periodFinish = startTime.add(period.mul(DURATION));
+                rewardRate = reward.div(periodFinish.sub(block.timestamp));
+            } else {
+                uint256 remaining = periodFinish.sub(block.timestamp);
+                uint256 leftover = remaining.mul(rewardRate);
+                rewardRate = reward.add(leftover).div(remaining);
+            }
+            lastUpdateTime = block.timestamp;
+        }else {
+          uint256 b = gof.balanceOf(address(this));
+          rewardRate = reward.add(b).div(DURATION);
+          periodFinish = startTime.add(DURATION);
+          lastUpdateTime = startTime;
+        }
+
+        gof.mint(address(this),reward);
+        emit RewardAdded(reward);
+
+        // avoid overflow to lock assets
+        _checkRewardRate();
+    }
+    
+    function _checkRewardRate() internal view returns (uint256) {
+        return DURATION.mul(rewardRate).mul(_gunit);
+    }
+}
\ No newline at end of file
diff --git a/contracts/pool/GOFGTPool.sol b/contracts/pool/GOFGTPool.sol
new file mode 100644
index 0000000..0421aa6
--- /dev/null
+++ b/contracts/pool/GOFGTPool.sol
@@ -0,0 +1,735 @@
+
+// File: @openzeppelin/contracts/math/Math.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @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, so we distribute
+        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
+    }
+}
+
+// File: @openzeppelin/contracts/math/SafeMath.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @dev Wrappers over Solidity's arithmetic operations with added overflow
+ * checks.
+ *
+ * Arithmetic operations in Solidity wrap on overflow. This can easily result
+ * in bugs, because programmers usually assume that an overflow raises an
+ * error, which is the standard behavior in high level programming languages.
+ * `SafeMath` restores this intuition by reverting the transaction when an
+ * operation overflows.
+ *
+ * Using this library instead of the unchecked operations eliminates an entire
+ * class of bugs, so it's recommended to use it always.
+ */
+library SafeMath {
+    /**
+     * @dev Returns the addition of two unsigned integers, reverting on
+     * overflow.
+     *
+     * Counterpart to Solidity's `+` operator.
+     *
+     * Requirements:
+     * - Addition cannot overflow.
+     */
+    function add(uint256 a, uint256 b) internal pure returns (uint256) {
+        uint256 c = a + b;
+        require(c >= a, "SafeMath: addition overflow");
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, reverting on
+     * overflow (when the result is negative).
+     *
+     * Counterpart to Solidity's `-` operator.
+     *
+     * Requirements:
+     * - Subtraction cannot overflow.
+     */
+    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
+        return sub(a, b, "SafeMath: subtraction overflow");
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
+     * overflow (when the result is negative).
+     *
+     * Counterpart to Solidity's `-` operator.
+     *
+     * Requirements:
+     * - Subtraction cannot overflow.
+     *
+     * _Available since v2.4.0._
+     */
+    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
+        require(b <= a, errorMessage);
+        uint256 c = a - b;
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the multiplication of two unsigned integers, reverting on
+     * overflow.
+     *
+     * Counterpart to Solidity's `*` operator.
+     *
+     * Requirements:
+     * - Multiplication cannot overflow.
+     */
+    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
+        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+        // benefit is lost if 'b' is also tested.
+        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
+        if (a == 0) {
+            return 0;
+        }
+
+        uint256 c = a * b;
+        require(c / a == b, "SafeMath: multiplication overflow");
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the integer division of two unsigned integers. Reverts on
+     * division by zero. The result is rounded towards zero.
+     *
+     * Counterpart to Solidity's `/` operator. Note: this function uses a
+     * `revert` opcode (which leaves remaining gas untouched) while Solidity
+     * uses an invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     */
+    function div(uint256 a, uint256 b) internal pure returns (uint256) {
+        return div(a, b, "SafeMath: division by zero");
+    }
+
+    /**
+     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
+     * division by zero. The result is rounded towards zero.
+     *
+     * Counterpart to Solidity's `/` operator. Note: this function uses a
+     * `revert` opcode (which leaves remaining gas untouched) while Solidity
+     * uses an invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     *
+     * _Available since v2.4.0._
+     */
+    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
+        // Solidity only automatically asserts when dividing by 0
+        require(b > 0, errorMessage);
+        uint256 c = a / b;
+        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
+
+        return c;
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
+     * Reverts when dividing by zero.
+     *
+     * Counterpart to Solidity's `%` operator. This function uses a `revert`
+     * opcode (which leaves remaining gas untouched) while Solidity uses an
+     * invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     */
+    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
+        return mod(a, b, "SafeMath: modulo by zero");
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
+     * Reverts with custom message when dividing by zero.
+     *
+     * Counterpart to Solidity's `%` operator. This function uses a `revert`
+     * opcode (which leaves remaining gas untouched) while Solidity uses an
+     * invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     * - The divisor cannot be zero.
+     *
+     * _Available since v2.4.0._
+     */
+    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
+        require(b != 0, errorMessage);
+        return a % b;
+    }
+}
+
+// File: @openzeppelin/contracts/GSN/Context.sol
+
+pragma solidity 0.5.16;
+
+/*
+ * @dev Provides information about the current execution context, including the
+ * sender of the transaction and its data. While these are generally available
+ * via msg.sender and msg.data, they should not be accessed in such a direct
+ * manner, since when dealing with GSN meta-transactions the account sending and
+ * paying for execution may not be the actual sender (as far as an application
+ * is concerned).
+ *
+ * This contract is only required for intermediate, library-like contracts.
+ */
+contract Context {
+    // Empty internal constructor, to prevent people from mistakenly deploying
+    // an instance of this contract, which should be used via inheritance.
+    constructor () internal { }
+    // solhint-disable-previous-line no-empty-blocks
+
+    function _msgSender() internal view returns (address payable) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view returns (bytes memory) {
+        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
+        return msg.data;
+    }
+}
+
+// File: @openzeppelin/contracts/ownership/Ownable.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @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.
+ *
+ * This module is used through inheritance. It will make available the modifier
+ * `onlyOwner`, which can be applied to your functions to restrict their use to
+ * the owner.
+ */
+contract Ownable is Context {
+    address private _owner;
+
+    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
+
+    /**
+     * @dev Initializes the contract setting the deployer as the initial owner.
+     */
+    constructor () internal {
+        _owner = _msgSender();
+        emit OwnershipTransferred(address(0), _owner);
+    }
+
+    /**
+     * @dev Returns the address of the current owner.
+     */
+    function owner() public view returns (address) {
+        return _owner;
+    }
+
+    /**
+     * @dev Throws if called by any account other than the owner.
+     */
+    modifier onlyOwner() {
+        require(isOwner(), "Ownable: caller is not the owner");
+        _;
+    }
+
+    /**
+     * @dev Returns true if the caller is the current owner.
+     */
+    function isOwner() public view returns (bool) {
+        return _msgSender() == _owner;
+    }
+
+    /**
+     * @dev Leaves the contract without owner. It will not be possible to call
+     * `onlyOwner` functions anymore. Can only be called by the current owner.
+     *
+     * NOTE: Renouncing ownership will leave the contract without an owner,
+     * thereby removing any functionality that is only available to the owner.
+     */
+    function renounceOwnership() public onlyOwner {
+        emit OwnershipTransferred(_owner, address(0));
+        _owner = address(0);
+    }
+
+    /**
+     * @dev Transfers ownership of the contract to a new account (`newOwner`).
+     * Can only be called by the current owner.
+     */
+    function transferOwnership(address newOwner) public onlyOwner {
+        _transferOwnership(newOwner);
+    }
+
+    /**
+     * @dev Transfers ownership of the contract to a new account (`newOwner`).
+     */
+    function _transferOwnership(address newOwner) internal {
+        require(newOwner != address(0), "Ownable: new owner is the zero address");
+        emit OwnershipTransferred(_owner, newOwner);
+        _owner = newOwner;
+    }
+}
+
+// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
+ * the optional functions; to access them see {ERC20Detailed}.
+ */
+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);
+    function mint(address account, uint amount) external;
+
+    /**
+     * @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/utils/Address.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @dev Collection of functions related to the address type
+ */
+library Address {
+    /**
+     * @dev Returns true if `account` is a contract.
+     *
+     * This test is non-exhaustive, and there may be false-negatives: during the
+     * execution of a contract's constructor, its address will be reported as
+     * not containing 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.
+     */
+    function isContract(address account) internal view returns (bool) {
+        // This method relies in extcodesize, which returns 0 for contracts in
+        // construction, since the code is only stored at the end of the
+        // constructor execution.
+
+        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
+        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
+        // for accounts without code, i.e. `keccak256('')`
+        bytes32 codehash;
+        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
+        // solhint-disable-next-line no-inline-assembly
+        assembly { codehash := extcodehash(account) }
+        return (codehash != 0x0 && codehash != accountHash);
+    }
+
+    /**
+     * @dev Converts an `address` into `address payable`. Note that this is
+     * simply a type cast: the actual underlying value is not changed.
+     *
+     * _Available since v2.4.0._
+     */
+    function toPayable(address account) internal pure returns (address payable) {
+        return address(uint160(account));
+    }
+
+    /**
+     * @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].
+     *
+     * _Available since v2.4.0._
+     */
+    function sendValue(address payable recipient, uint256 amount) internal {
+        require(address(this).balance >= amount, "Address: insufficient balance");
+
+        // solhint-disable-next-line avoid-call-value
+        (bool success, ) = recipient.call.value(amount)("");
+        require(success, "Address: unable to send value, recipient may have reverted");
+    }
+}
+
+// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol
+
+pragma solidity 0.5.16;
+
+/**
+ * @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 ERC20;` statement to your contract,
+ * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
+ */
+library SafeERC20 {
+    using SafeMath for uint256;
+    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));
+    }
+
+    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'
+        // solhint-disable-next-line max-line-length
+        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).add(value);
+        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
+    }
+
+    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
+        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
+        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
+    }
+
+    /**
+     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
+     * on the return value: the return value is optional (but if data is returned, it must not be false).
+     * @param token The token targeted by the call.
+     * @param data The call data (encoded using abi.encode or one of its variants).
+     */
+    function callOptionalReturn(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.
+
+        // A Solidity high level call has three parts:
+        //  1. The target address is checked to verify it contains contract code
+        //  2. The call itself is made, and success asserted
+        //  3. The return value is decoded, which in turn checks the size of the returned data.
+        // solhint-disable-next-line max-line-length
+        require(address(token).isContract(), "SafeERC20: call to non-contract");
+
+        // solhint-disable-next-line avoid-low-level-calls
+        (bool success, bytes memory returndata) = address(token).call(data);
+        require(success, "SafeERC20: low-level call failed");
+
+        if (returndata.length > 0) { // Return data is optional
+            // solhint-disable-next-line max-line-length
+            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
+        }
+    }
+}
+
+/**
+ * Reward Amount Interface
+ */
+pragma solidity 0.5.16;
+
+contract IRewardDistributionRecipient is Ownable {
+    address rewardDistribution;
+
+    function notifyRewardAmount(uint256 reward) external;
+
+    modifier onlyRewardDistribution() {
+        require(_msgSender() == rewardDistribution, "Caller is not reward distribution");
+        _;
+    }
+
+    function setRewardDistribution(address _rewardDistribution)
+        external
+        onlyOwner
+    {
+        rewardDistribution = _rewardDistribution;
+    }
+}
+
+ /**
+  * Staking Token Wrapper
+  */
+pragma solidity 0.5.16;
+
+contract GOFTokenWrapper {
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
+
+    IERC20 public stakeToken = IERC20(0xE66747a101bFF2dBA3697199DCcE5b743b454759);
+    
+    uint256 private _totalSupply;
+    mapping(address => uint256) private _balances;
+
+    function totalSupply() public view returns (uint256) {
+        return _totalSupply;
+    }
+
+    function balanceOf(address account) public view returns (uint256) {
+        return _balances[account];
+    }
+
+    function stake(uint256 amount) public {
+        uint256 _before = stakeToken.balanceOf(address(this));
+        stakeToken.safeTransferFrom(msg.sender, address(this), amount);
+        uint256 _after = stakeToken.balanceOf(address(this));
+        uint256 _amount = _after.sub(_before);
+        
+        _totalSupply = _totalSupply.add(_amount);
+        _balances[msg.sender] = _balances[msg.sender].add(_amount);
+    }
+
+    function withdraw(uint256 amount) public {
+        _totalSupply = _totalSupply.sub(amount);
+        _balances[msg.sender] = _balances[msg.sender].sub(amount);
+        stakeToken.safeTransfer(msg.sender, amount);
+    }
+}
+
+/**
+ *  Pool
+ */
+pragma solidity 0.5.16;
+
+contract GOFGTPool is GOFTokenWrapper, IRewardDistributionRecipient {
+    
+    IERC20 public gof = IERC20(0x488E0369f9BC5C40C002eA7c1fe4fd01A198801c);
+    uint256 public constant DURATION = 7 days;
+
+    uint256 public constant startTime = 1602676800; //utc+8 2020-10-14 20:00:00
+    uint256 public periodFinish = 0;
+    uint256 public rewardRate = 0;
+    uint256 public lastUpdateTime;
+    uint256 public rewardPerTokenStored = 0;
+    bool private open = true;
+    uint256 private constant _gunit = 1e18;
+    mapping(address => uint256) public userRewardPerTokenPaid; 
+    mapping(address => uint256) public rewards; // Unclaimed rewards
+
+    event RewardAdded(uint256 reward);
+    event Staked(address indexed user, uint256 amount);
+    event Withdrawn(address indexed user, uint256 amount);
+    event RewardPaid(address indexed user, uint256 reward);
+    event SetOpen(bool _open);
+
+    modifier updateReward(address account) {
+        rewardPerTokenStored = rewardPerToken();
+        lastUpdateTime = lastTimeRewardApplicable();
+        if (account != address(0)) {
+            rewards[account] = earned(account);
+            userRewardPerTokenPaid[account] = rewardPerTokenStored;
+        }
+        _;
+    }
+
+    function lastTimeRewardApplicable() public view returns (uint256) {
+        return Math.min(block.timestamp, periodFinish);
+    }
+
+    /**
+     * Calculate the rewards for each token
+     */
+    function rewardPerToken() public view returns (uint256) {
+        if (totalSupply() == 0) {
+            return rewardPerTokenStored;
+        }
+        return
+            rewardPerTokenStored.add(
+                lastTimeRewardApplicable()
+                    .sub(lastUpdateTime)
+                    .mul(rewardRate)
+                    .mul(_gunit)
+                    .div(totalSupply())
+            );
+    }
+
+    function earned(address account) public view returns (uint256) {
+        return
+            balanceOf(account)
+                .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))
+                .div(_gunit)
+                .add(rewards[account]);
+    }
+
+    function stake(uint256 amount) public checkOpen checkStart updateReward(msg.sender){ 
+        require(amount > 0, "Golff-POOL: Cannot stake 0");
+        super.stake(amount);
+        emit Staked(msg.sender, amount);
+    }
+
+    function withdraw(uint256 amount) public checkStart updateReward(msg.sender){
+        require(amount > 0, "Golff-POOL: Cannot withdraw 0");
+        super.withdraw(amount);
+        emit Withdrawn(msg.sender, amount);
+    }
+
+    function exit() external {
+        withdraw(balanceOf(msg.sender));
+        getReward();
+    }
+
+    function getReward() public checkStart updateReward(msg.sender){
+        uint256 reward = earned(msg.sender);
+        if (reward > 0) {
+            rewards[msg.sender] = 0;
+            gof.safeTransfer(msg.sender, reward);
+            emit RewardPaid(msg.sender, reward);
+        }
+    }
+
+    modifier checkStart(){
+        require(block.timestamp > startTime,"Golff-POOL: Not start");
+        _;
+    }
+
+    modifier checkOpen() {
+        require(open, "Golff-POOL: Pool is closed");
+        _;
+    }
+
+    function getPeriodFinish() external view returns (uint256) {
+        return periodFinish;
+    }
+
+    function isOpen() external view returns (bool) {
+        return open;
+    }
+
+    function setOpen(bool _open) external onlyOwner {
+        open = _open;
+        emit SetOpen(_open);
+    }
+
+    function notifyRewardAmount(uint256 reward)
+        external
+        onlyRewardDistribution
+        checkOpen
+        updateReward(address(0)){
+        if (block.timestamp > startTime){
+            if (block.timestamp >= periodFinish) {
+                uint256 period = block.timestamp.sub(startTime).div(DURATION).add(1);
+                periodFinish = startTime.add(period.mul(DURATION));
+                rewardRate = reward.div(periodFinish.sub(block.timestamp));
+            } else {
+                uint256 remaining = periodFinish.sub(block.timestamp);
+                uint256 leftover = remaining.mul(rewardRate);
+                rewardRate = reward.add(leftover).div(remaining);
+            }
+            lastUpdateTime = block.timestamp;
+        }else {
+          uint256 b = gof.balanceOf(address(this));
+          rewardRate = reward.add(b).div(DURATION);
+          periodFinish = startTime.add(DURATION);
+          lastUpdateTime = startTime;
+        }
+
+        gof.mint(address(this),reward);
+        emit RewardAdded(reward);
+
+        // avoid overflow to lock assets
+        _checkRewardRate();
+    }
+    
+    function _checkRewardRate() internal view returns (uint256) {
+        return DURATION.mul(rewardRate).mul(_gunit);
+    }
+}
\ No newline at end of file