pragma solidity ^0.5.0;


library Math {
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        return (a / 2) + (b / 2) + (((a % 2) + (b % 2)) / 2);
    }
}

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;

        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

contract Context {
    constructor() internal {}

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this;
        return msg.data;
    }
}

contract Ownable is Context {
    address private _owner;

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

    constructor() internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);

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

    function transfer(address recipient, uint256 amount)
        external
        returns (bool);

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

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

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

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

library Address {
    function isContract(address account) internal view returns (bool) {
        bytes32 codehash;
        bytes32 accountHash =
            0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;

        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != 0x0 && codehash != accountHash);
    }

    function toPayable(address account)
        internal
        pure
        returns (address payable)
    {
        return address(uint160(account));
    }

    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"
        );
    }
}

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 {
        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
            )
        );
    }

    function callOptionalReturn(IERC20 token, bytes memory data) private {
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) {
            // Return data is optional

            require(
                abi.decode(returndata, (bool)),
                "SafeERC20: ERC20 operation did not succeed"
            );
        }
    }
}

contract LPTokenWrapper is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    IERC20 public BUND = IERC20(0x8D3E855f3f55109D473735aB76F753218400fe96); // Approve and Transfer for Stake and Withdraw

    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 {
        _totalSupply = _totalSupply.add(amount);
        _balances[msg.sender] = _balances[msg.sender].add(amount);
        BUND.safeTransferFrom(msg.sender, address(this), amount);
    }

    function withdraw(uint256 amount) public {
        _totalSupply = _totalSupply.sub(amount);
        _balances[msg.sender] = _balances[msg.sender].sub(amount);
        BUND.safeTransfer(msg.sender, amount);
    }
}

contract StakeBUND is LPTokenWrapper {
    IERC20 public bundNFT = IERC20(0x92B3367515a7D2dF838c2ccD9F5e1Fc07D977C20); // Must be changed with Presale
    uint256 public constant duration = 30 days;
    
    uint256 public starttime = 1614749400;              //-----| Starts immediately after deploy |-----                           
    uint256 public periodFinish = 0;
    uint256 public rewardRate = 0;
    uint256 public lastUpdateTime;
    uint256 public rewardPerTokenStored;
    bool firstNotify;
  
    uint256 rewardAmount = 0;

    mapping(address => uint256) public userRewardPerTokenPaid;
    mapping(address => uint256) public rewards;

    event RewardAdded(uint256 reward);
    event Staked(address indexed user, uint256 amount);
    event Withdrawn(address indexed user, uint256 amount);
    event Rewarded(address indexed from, address indexed to, uint256 value);

    modifier checkStart() {
        require(
            block.timestamp >= starttime,
            "BUND_BUNDNFT staking pool not started yet."
        );
        _;
    }

    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);
    }

    function rewardPerToken() public view 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 returns (uint256) {
        return
            balanceOf(account)
                .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))
                .div(1e18)
                .add(rewards[account]);
    }

    function stake(uint256 amount) public updateReward(msg.sender) checkStart {
        require(amount > 0, "Cannot stake 0");
        super.stake(amount);
    }

    function withdraw(uint256 amount)
        public
        updateReward(msg.sender)
    {
        require(amount > 0, "Cannot withdraw 0");
        super.withdraw(amount);
    }

    // withdraw stake and get rewards at once
    function exit() external {
        withdraw(balanceOf(msg.sender));
        getReward();
    }

    function getReward() public updateReward(msg.sender){
        uint256 reward = earned(msg.sender);

        if (reward > 0) {
            rewards[msg.sender] = 0;
        
            bundNFT.safeTransfer(msg.sender, reward);
        }
        
    }

    function permitNotifyReward() public view returns (bool) {    //-----| If current reward session has completed |---------
        
        if(block.timestamp > starttime.add(duration)){
           return true;
        }
         
    }
 
    function notifyRewardRate(uint256 _reward) public updateReward(address(0)) onlyOwner{
       
        require(permitNotifyReward() == true || firstNotify == false, "Cannot notify until previous reward session is completed");
        
        rewardRate = _reward.div(duration);
       
        firstNotify = true;
        lastUpdateTime = block.timestamp;
        starttime = block.timestamp; 
        periodFinish = block.timestamp.add(duration);

    }
}

{
  "compilationTarget": {
    "StakeBUND.sol": "StakeBUND"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}