contract StakingPool is Ownable, ReentrancyGuard, LPTokenWrapper {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;
    using Address for address;

    //Conctact status states
    enum Status {Setup, Running, Ended}
    //Status of contract
    Status public status;
    //Time when contracts starts
    uint256 public startTime;
    //Time when contract ends 
    uint256 public endTime;
    //Time when contract closes (endTime + gracePeriodTime)
    uint256 public closeTime;
    //Last Period
    uint256 public period;
    
    //Constants
    uint256 constant public CALC_PRECISION = 1e18;

    //Interface for Rewards Token
    IERC20 public rewardsToken;
    //Interface for Extra Rewards Token
    IERC20 public rewardsExtraToken;
    //Address where to send remaining tokens after contract closes
    address rewardsExtraOwner;
    //Rewards for period
    uint256 public rewardsPerPeriodCap;
    //Rewards Extra for period
    uint256 public rewardsExtraPerPeriodCap;
    //Staking Period in seconds
    uint256 public periodTime;
    //Total Periods
    uint256 public totalPeriods;
    //Grace Periods Time (time window after contract is Ended when users have to claim their Reward Tokens)
    //after this period ends, no reward withdrawal is possible and contact owner can withdraw unclamed Reward Tokens
    uint256 public gracePeriodTime;
    //Address where fees will be sent if fee isn't 0
    address public feeBeneficiary;
    //Fee in PPM (Parts Per Million), can be 0
    uint256 public fee;
    //Hold in periods for rewards
    uint256 public holdRewardsPeriods;
    
    event Staked(address indexed user, uint256 amount);
    event Withdrawn(address indexed user, uint256 amount);
    event RewardPaid(address indexed user, uint256 reward);
    event RewardExtraPaid(address indexed user, uint256 rewardExtra);
    event WithdrawnERC20(address indexed user, address token, uint256 amount);
    

    /** @dev Updates Period before executing function */
    modifier updatePeriod() {
        _updatePeriod();
        _;
    }
    
    /** @dev Make sure setup is finished */
    modifier onlyAfterSetup() {
        require(status != Status.Setup, "Setup is not finished");
        _;
    }

    /** @dev Make sure setup is finished */
    modifier onlyAfterStart() {
        require(startTime != 0, "Staking is not started");
        _;
    }

    /**
     * @dev Contract constructor
     * @param _lpToken Contract address of LP Token
     * @param _rewardsToken Contract address of Rewards Token
     * @param _rewardsPerPeriodCap Amount of tokens to be distributed each period
     * @param _periodDays Period time in days
     * @param _totalPeriods Total periods contract will be running
     * @param _gracePeriodDays Grace period in days 
     * @param _holdDays Time in days LP Tokens will be on hold for user after each stake
     * @param _feeBeneficiary Address where fees will be sent
     * @param _fee Fee in ppm
     * @param _holdRewardsPeriods hold for rewards in periods
     */
    constructor(
        address _lpToken,
        address _rewardsToken,
        uint256 _rewardsPerPeriodCap,
        uint256 _periodDays, 
        uint256 _totalPeriods,
        uint256 _gracePeriodDays,
        uint256 _holdDays,
        address _feeBeneficiary,
        uint256 _fee,
        uint256 _holdRewardsPeriods
    )
        public
        LPTokenWrapper(_lpToken, _holdDays)
    {
        require(_lpToken.isContract(), "LP Token address must be a contract");
        require(_rewardsToken.isContract(), "Rewards Token address must be a contract");
        rewardsToken = IERC20(_rewardsToken);
        rewardsPerPeriodCap = _rewardsPerPeriodCap;
        periodTime = _periodDays.mul(1 days);
        totalPeriods = _totalPeriods;
        gracePeriodTime = _gracePeriodDays.mul(1 days);
        feeBeneficiary = _feeBeneficiary;
        fee = _fee;
        holdRewardsPeriods = _holdRewardsPeriods;
    }

    /***************************************
                    ADMIN
    ****************************************/

    /**
     * @dev Adds Rewards Extra token to contract, can be done only during setup
     * @param _rewardsExtraToken Contract address of Extra Rewards Token
     * @param _rewardsExtraPerPeriodCap Amount of tokens to be distributed each period
     * @param _rewardsExtraOwner address where to send remaining tokens after contract closes
     */    
    function adminAddRewardsExtraToken(
        address _rewardsExtraToken,
        uint256 _rewardsExtraPerPeriodCap,
        address _rewardsExtraOwner
    ) 
        external 
        onlyOwner
    {
        require(status == Status.Setup, "Already started");
        require(_rewardsExtraToken.isContract(), "Rewards Token address must be a contract");
        rewardsExtraToken = IERC20(_rewardsExtraToken);
        rewardsExtraPerPeriodCap = _rewardsExtraPerPeriodCap;
        rewardsExtraOwner = _rewardsExtraOwner;
    }

    /**
     * @dev Updates contract setup and mark contract status as Running if all requirements are met
     * @param _now Start contract immediatly if true
     */    
    function adminStart(bool _now) 
        external 
        onlyOwner
    {
        require(status == Status.Setup, "Already started");
        require(
            rewardsToken.balanceOf(address(this)) >= rewardsPerPeriodCap.mul(totalPeriods),
            "Not enough reward tokens to start"
        );
        if(address(rewardsExtraToken) != address(0)){
            require(
                rewardsExtraToken.balanceOf(address(this)) >= rewardsExtraPerPeriodCap.mul(totalPeriods),
                "Not enough extra reward tokens to start"
            );
        }
        status = Status.Running;
        if(_now) _startNow();
    }
    
    /**
     * @dev Option to start contract even there is no deposits yet
     */
    function adminStartNow()
        external
        onlyOwner
        onlyAfterSetup
    {
        require(startTime == 0 && status == Status.Running, "Already started");
        _startNow();
        
    }
    
    /**
     * @dev Option to end contract 
     */
    function adminEnd()
        external
        onlyOwner
        onlyAfterSetup
    {
        require(block.timestamp >= endTime && endTime != 0, "Cannot End");
        _updatePeriod();
    }
    
    /**
     * @dev Close contract after End and Grace period and withdraw unclamed rewards tokens
     */
     function adminClose()
        external
        onlyOwner
        onlyAfterSetup
    {
        require(block.timestamp >= closeTime && closeTime != 0, "Cannot Close");
        uint256 _rewardsBalance = rewardsToken.balanceOf(address(this));
        if(_rewardsBalance > 0) rewardsToken.safeTransfer(msg.sender, _rewardsBalance);
        if(address(rewardsExtraToken) != address(0)){
            _rewardsBalance = rewardsExtraToken.balanceOf(address(this));
            if(_rewardsBalance > 0) rewardsExtraToken.safeTransfer(rewardsExtraOwner, _rewardsBalance);
        }
    }
    
    /**
     * @dev Withdraw other than LP or Rewards tokens 
     * @param _tokenAddress address of the token contract to withdraw
     */
     function adminWithdrawERC20(address _tokenAddress)
        external
        onlyOwner
    {
        require(
            _tokenAddress != address(rewardsToken) 
            && _tokenAddress != address(rewardsExtraToken) 
            && _tokenAddress != address(lpToken), 
            "Cannot withdraw Reward or LP Tokens"
        );
        IERC20 _token = IERC20(_tokenAddress);
        uint256 _balance = _token.balanceOf(address(this));
        require(_balance != 0, "Not enough balance");
        uint256 _fee = _balance.mul(fee).div(1e6);
        if(_fee != 0){
            _token.safeTransfer(feeBeneficiary, _fee);
            emit WithdrawnERC20(feeBeneficiary, _tokenAddress, _fee);
        }
        _token.safeTransfer(msg.sender, _balance.sub(_fee));
        emit WithdrawnERC20(msg.sender, _tokenAddress, _balance.sub(_fee));
    }
    
    /***************************************
                    PRIVATE
    ****************************************/
    
    /**
     * @dev Starts the contract
     */
    function _startNow()
        private
    {
        startTime = block.timestamp;
        endTime = startTime.add(periodTime.mul(totalPeriods));  
        closeTime = endTime.add(gracePeriodTime);
    }

    /**
     * @dev Updates last period to current and set status to Ended if needed
     */
    function _updatePeriod()
        private
    {
        uint256 _currentPeriod = currentPeriod();
        if(_currentPeriod != period){
            period = _currentPeriod;
            if(_currentPeriod == totalPeriods){
                status = Status.Ended;
                //release hold of LP tokens
                holdTime = 0;
                //release hold of rewards
                holdRewardsPeriods = 0;
            }
        }
    }

    /**
     * @dev Calculates rewards share, balance for the user and history total supply
     * since last period claimed rewards to period provided
     * @param _address address of the user
     * @param _period last period to include
     */
    function _calculateRewardShare(address _address, uint256 _period) 
        private
        view
        returns (uint256 rewardShare_, uint256 periodBalance_, uint256 periodTotalSupply_)
    {
        UserData storage _user = _getUserData(_address);
        if(_period > _user.period){
            uint256 _savedTotalSupply;
            uint256 _savedBalance;
            for(uint256 i = _user.period; i < _period; i++){
                if(historyTotalSupply[i].isSet){
                    periodTotalSupply_ = historyTotalSupply[i].value;
                    _savedTotalSupply = periodTotalSupply_;
                }else{
                    periodTotalSupply_ = _savedTotalSupply;
                } 
                if(_user.historyBalance[i].isSet){
                    periodBalance_ = _user.historyBalance[i].value;
                    _savedBalance = periodBalance_;
                }else{
                    periodBalance_ = _savedBalance;
                }        
                if(periodTotalSupply_ != 0){
                    rewardShare_ = rewardShare_.add(
                        periodBalance_.mul(
                            CALC_PRECISION
                        ).div(
                            periodTotalSupply_
                        )
                    );
                }
            }
            if(historyTotalSupply[_period].isSet)
                    periodTotalSupply_ = historyTotalSupply[_period].value;
            if(_user.historyBalance[_period].isSet)
                    periodBalance_ = _user.historyBalance[_period].value;
        }
    }
    
    /**
     * @dev Calculates rewards since last period claimed rewards to period provided
     * @param _address address of the user
     * @param _period last period to include
     * @param _rewardsPerPeriodCap rewards per period cap
     */
    function _calculateReward(address _address, uint256 _period, uint256 _rewardsPerPeriodCap) 
        private
        view
        returns (uint256 reward_)
    {
        if(block.timestamp >= closeTime) return 0;
        (reward_, , ) = _calculateRewardShare(_address, _period);
        reward_ = _rewardsPerPeriodCap.mul(reward_).div(CALC_PRECISION);
    } 

    /***************************************
                    ACTIONS
    ****************************************/
    
    /**
     * @dev Stakes an amount for the sender, assumes sender approved allowace at LP Token contract _amount for this contract address
     * @param _amount of LP Tokens
     */
    function stake(uint256 _amount)
        external
        onlyAfterSetup
        updatePeriod
    {
        require(_amount > 0, "Cannot stake 0");
        require(status != Status.Ended, "Contract is Ended");
        if(startTime == 0) _startNow();
        _stake(_amount, period);
        emit Staked(msg.sender, _amount);
    }

    /**
     * @dev Withdraws given LP Token stake amount from the pool
     * @param _amount LP Tokens to withdraw
     */
    function withdraw(uint256 _amount)
        public
        onlyAfterStart
        updatePeriod
    {
        require(_amount > 0, "Cannot withdraw 0");
        _withdraw(_amount, period);
        emit Withdrawn(msg.sender, _amount);
    }
    
    /**
     * @dev Claims outstanding rewards for the sender.
     * First updates outstanding reward allocation and then transfers.
     */
    function claimReward()
        public
        nonReentrant
        onlyAfterStart
        updatePeriod
        returns (uint256 reward_, uint256 rewardExtra_)
    {
        require(block.timestamp < closeTime, "Contract is Closed");
        if(period > holdRewardsPeriods){
            uint256 _period = period.sub(holdRewardsPeriods);
            uint256 _rewardShare;
            uint256 _periodBalance;
            uint256 _periodTotalSupply;
            (_rewardShare, _periodBalance, _periodTotalSupply) = _calculateRewardShare(
                msg.sender, 
                _period
            );
            if (_rewardShare > 0) {            
                _updateUser(msg.sender, _period, _periodBalance);
                _updateHistoryTotalSupply(_period, _periodTotalSupply);
                reward_ = rewardsPerPeriodCap.mul(_rewardShare).div(CALC_PRECISION);
                rewardsToken.safeTransfer(msg.sender, reward_);
                emit RewardPaid(msg.sender, reward_);
                if(address(rewardsExtraToken) != address(0)){
                    rewardExtra_ = rewardsExtraPerPeriodCap.mul(_rewardShare).div(CALC_PRECISION);
                    rewardsExtraToken.safeTransfer(msg.sender, rewardExtra_);
                    emit RewardExtraPaid(msg.sender, rewardExtra_);
                }
            }
        }
    }    
    
    /**
     * @dev Withdraws LP Tokens stake from pool and claims any rewards
     */
    function exit() 
        external
    {
        uint256 _amount = balanceOf(msg.sender);
        if(_amount !=0) withdraw(_amount);
        claimReward();
    }
    
    /***************************************
                    GETTERS
    ****************************************/

    /**
     * @dev Calculates current period, if contract is ended returns currentPeriod + 1 (totalPeriods)
     */
    function currentPeriod() 
        public 
        view 
        returns (uint256 currentPeriod_)
    {
        if(startTime != 0 && endTime != 0)
        {
            if(block.timestamp >= endTime){
                currentPeriod_ = totalPeriods;
            }else{
                currentPeriod_ = block.timestamp.sub(startTime).div(periodTime);
            }
        }
    }

    /**
     * @dev Calculates rewards for the user since last period claimed rewards 
     * available for withdraw (taking into account hold periods for rewards)
     * @param _address address of the user
     */
    function calculateReward(address _address) 
        external
        view
        returns (uint256 reward_)
    {
        uint256 _period = currentPeriod();
        if(_period == totalPeriods)
            return calculateRewardTotal(_address);
        if(_period > holdRewardsPeriods)
            reward_ = _calculateReward(_address, _period.sub(holdRewardsPeriods), rewardsPerPeriodCap);
    }

    /**
     * @dev Calculates extra rewards for the user since last period claimed rewards 
     * available for withdraw (taking into account hold periods for rewards)
     * @param _address address of the user
     */
    function calculateRewardExtra(address _address) 
        external
        view
        returns (uint256 rewardExtra_)
    {
        if(address(rewardsExtraToken) != address(0)){
            uint256 _period = currentPeriod();
            if(_period == totalPeriods)
                return calculateRewardExtraTotal(_address);
            if(_period > holdRewardsPeriods)
                rewardExtra_ = _calculateReward(_address, 
                    _period.sub(holdRewardsPeriods), 
                    rewardsExtraPerPeriodCap
                );
        }  
    }

    /**
     * @dev Calculates total rewards (including those on hold if any) for the user till current period 
     * @param _address address of the user
     */
    function calculateRewardTotal(address _address) 
        public
        view
        returns (uint256)
    {
        return _calculateReward(_address, currentPeriod(), rewardsPerPeriodCap);
    }

    /**
     * @dev Calculates total rewards extra (including those on hold if any) for the user till current period 
     * @param _address address of the user
     */
    function calculateRewardExtraTotal(address _address) 
        public
        view
        returns (uint256)
    {
        if(address(rewardsExtraToken) != address(0))
            return _calculateReward(_address, currentPeriod(), rewardsExtraPerPeriodCap);
        
    }

    /**
     * @dev Returns estimated current period reward for the user based on current total supply and his balance
     * @param _address address of the user
     */
    function estimateReward(address _address) 
        external
        view
        returns (uint256)
    {
        if(totalSupply == 0 || block.timestamp >= endTime) return 0;
        return rewardsPerPeriodCap.mul(
            balanceOf(_address)
        ).mul(
            CALC_PRECISION
        ).div(
            totalSupply
        ).div(
            CALC_PRECISION
        );
    }

    /**
     * @dev Returns estimated current period reward extra for the user based on current total supply and his balance
     * @param _address address of the user
     */
    function estimateRewardExtra(address _address) 
        external
        view
        returns (uint256)
    {
        if(address(rewardsExtraToken) != address(0)){
            if(totalSupply == 0 || block.timestamp >= endTime) return 0;
            return rewardsExtraPerPeriodCap.mul(
                balanceOf(_address)
            ).mul(
                CALC_PRECISION
            ).div(
                totalSupply
            ).div(
                CALC_PRECISION
            );
        }
    }

    /**
     * @dev Returns Total reward cap for all periods
     */
    function rewardsTotalCap()
        external
        view
        returns (uint256)
    {
        return rewardsPerPeriodCap.mul(totalPeriods);
    }

    /**
     * @dev Returns Total reward extra cap for all periods
     */
    function rewardsExtraTotalCap()
        external
        view
        returns (uint256)
    {
        return rewardsExtraPerPeriodCap.mul(totalPeriods);
    }

    /**
     * @dev Returns true if hold for withdraw is active for given user address
     * @param _address address of the user
     */
    function isOnHold(address _address)
        external
        view
        returns (bool _hold)
    {
        UserData storage _user = _getUserData(_address);
        if(_user.lastTime == 0 || block.timestamp >= endTime){
            _hold = false;
        }else{
            _hold = block.timestamp.sub(_user.lastTime) < holdTime;
        }
    }
}
// 
function _calculateRewardShare(address _address, uint256 _period) 
    private
    view
    returns (uint256 rewardShare_, uint256 periodBalance_, uint256 periodTotalSupply_)
{
    UserData storage _user = _getUserData(_address);
    if(_period > _user.period){
        uint256 _savedTotalSupply;
        uint256 _savedBalance;
        for(uint256 i = _user.period; i < _period; i++){
            if(historyTotalSupply[i].isSet){
                periodTotalSupply_ = historyTotalSupply[i].value;
                _savedTotalSupply = periodTotalSupply_;
            }else{
                periodTotalSupply_ = _savedTotalSupply;
            } 
            if(_user.historyBalance[i].isSet){
                periodBalance_ = _user.historyBalance[i].value;
                _savedBalance = periodBalance_;
            }else{
                periodBalance_ = _savedBalance;
            }        
            if(periodTotalSupply_ != 0){
                rewardShare_ = rewardShare_.add(
                    periodBalance_.mul(
                        CALC_PRECISION
                    ).div(
                        periodTotalSupply_
                    )
                );
            }
        }
        if(historyTotalSupply[_period].isSet)
                periodTotalSupply_ = historyTotalSupply[_period].value;
        if(_user.historyBalance[_period].isSet)
                periodBalance_ = _user.historyBalance[_period].value;
    }
}

/**
 * @dev Calculates rewards share, balance for the user and history total supply
 * since last period claimed rewards to period provided
 * @param _address address of the user
 * @param _period last period to include
 */