contract UsdcGrowBurst is LPTokenWrapper, Ownable {
    using SafeERC20 for ERC20PresetMinterPauser;
    using SafeERC20 for IERC20;
    ERC20PresetMinterPauser public rewardToken;
    IERC20 public multiplierToken;

    uint256 public DURATION;
    uint256 public periodFinish;
    uint256 public rewardRate;
    uint256 public lastUpdateTime;
    uint256 public rewardPerTokenStored;
    uint256 public deployedTime;
    uint256 public multiplierTokenDevFund;

    uint256 public constant boostLevelOneCost = 250000000000000000;
    uint256 public constant boostLevelTwoCost = 500000000000000000;
    uint256 public constant boostLevelThreeCost = 1 * 1e18;
    uint256 public constant boostLevelFourCost = 2 * 1e18;

    uint256 public constant FivePercentBonus = 50000000000000000;
    uint256 public constant TwentyPercentBonus = 200000000000000000;
    uint256 public constant FourtyPercentBonus = 400000000000000000;
    uint256 public constant HundredPercentBonus = 1000000000000000000;

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

    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    event Withdrawn(address indexed user, uint256 amount);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 Boost(uint256 level);

    constructor(
        address _stakingToken,
        address _rewardToken,
        address _multiplierToken,
        uint256 _startTime,
        uint256 _duration
    ) public LPTokenWrapper(_startTime) {
        setStakingToken(_stakingToken);
        rewardToken = ERC20PresetMinterPauser(_rewardToken);
        multiplierToken = IERC20(_multiplierToken);
        deployedTime = block.timestamp;
        DURATION = _duration;
    }

    function setOwner(address _newOwner) external onlyOwner {
        super.transferOwnership(_newOwner);
    }

    function lastTimeRewardApplicable() public view returns (uint256) {
        return Math.min(block.timestamp, periodFinish);
    }

    // Returns the current rate of rewards per token (doh)
    function rewardPerToken() public view returns (uint256) {
        // Do not distribute rewards before games begin
        if (block.timestamp < startTime) {
            return 0;
        }
        if (_totalSupply == 0) {
            return rewardPerTokenStored;
        }
        // Effective total supply takes into account all the multipliers bought.
        uint256 effectiveTotalSupply = _totalSupply.add(_totalSupplyAccounting);
        return
            rewardPerTokenStored.add(
                lastTimeRewardApplicable()
                    .sub(lastUpdateTime)
                    .mul(rewardRate)
                    .mul(1e18)
                    .div(effectiveTotalSupply)
            );
    }

    // Returns the current reward tokens that the user can claim.
    function earned(address account) public view returns (uint256) {
        // Each user has it's own effective balance which is just the staked balance multiplied by boost level multiplier.
        uint256 effectiveBalance = _balances[account].add(
            _balancesAccounting[account]
        );
        return
            effectiveBalance
                .mul(rewardPerToken().sub(userRewardPerTokenPaid[account]))
                .div(1e18)
                .add(rewards[account]);
    }

    // Staking function which updates the user balances in the parent contract
    function stake(uint256 amount) public override {
        updateReward(msg.sender);
        require(amount > 0, "Cannot stake 0");
        super.stake(amount);

        // Users that have bought multipliers will have an extra balance added to their stake according to the boost multiplier.
        if (boostLevel[msg.sender] > 0) {
            uint256 prevBalancesAccounting = _balancesAccounting[msg.sender];
            // Calculate and set user's new accounting balance
            uint256 accTotalMultiplier = getTotalMultiplier(msg.sender);
            uint256 newBalancesAccounting = _balances[msg.sender]
                .mul(accTotalMultiplier)
                .div(1e18)
                .sub(_balances[msg.sender]);
            _balancesAccounting[msg.sender] = newBalancesAccounting;
            // Adjust total accounting supply accordingly
            uint256 diffBalancesAccounting = newBalancesAccounting.sub(
                prevBalancesAccounting
            );
            _totalSupplyAccounting = _totalSupplyAccounting.add(
                diffBalancesAccounting
            );
        }

        emit Staked(msg.sender, amount);
    }

    // Withdraw function to remove stake from the pool
    function withdraw(uint256 amount) public override {
        require(amount > 0, "Cannot withdraw 0");
        updateReward(msg.sender);
        super.withdraw(amount);

        // Users who have bought multipliers will have their accounting balances readjusted.
        if (boostLevel[msg.sender] > 0) {
            // The previous extra balance user had
            uint256 prevBalancesAccounting = _balancesAccounting[msg.sender];
            // Calculate and set user's new accounting balance
            uint256 accTotalMultiplier = getTotalMultiplier(msg.sender);
            uint256 newBalancesAccounting = _balances[msg.sender]
                .mul(accTotalMultiplier)
                .div(1e18)
                .sub(_balances[msg.sender]);
            _balancesAccounting[msg.sender] = newBalancesAccounting;
            // Subtract the withdrawn amount from the accounting balance
            // If all tokens are withdrawn the balance will be 0.
            uint256 diffBalancesAccounting = prevBalancesAccounting.sub(
                newBalancesAccounting
            );
            _totalSupplyAccounting = _totalSupplyAccounting.sub(
                diffBalancesAccounting
            );
        }

        emit Withdrawn(msg.sender, amount);
    }

    // Get the earned rewards and withdraw staked tokens
    function exit() external {
        getReward();
        withdraw(balanceOf(msg.sender));
    }

    // Sends out the reward tokens to the user.
    function getReward() public {
        updateReward(msg.sender);
        uint256 reward = earned(msg.sender);
        if (reward > 0) {
            rewards[msg.sender] = 0;
            rewardToken.mint(msg.sender, reward);
            emit RewardPaid(msg.sender, reward);
        }
    }

    // Called to start the pool with the reward amount it should distribute
    // The reward period will be the duration of the pool.
    function notifyRewardAmount(uint256 reward) external onlyOwner {
        updateRewardPerTokenStored();
        if (block.timestamp >= periodFinish) {
            rewardRate = reward.div(DURATION);
        } else {
            uint256 remaining = periodFinish.sub(block.timestamp);
            uint256 leftover = remaining.mul(rewardRate);
            rewardRate = reward.add(leftover).div(DURATION);
        }
        lastUpdateTime = block.timestamp;
        periodFinish = block.timestamp.add(DURATION);
        emit RewardAdded(reward);
    }

    // Notify the reward amount without updating time;
    function notifyRewardAmountWithoutUpdateTime(uint256 reward)
        external
        onlyOwner
    {
        updateRewardPerTokenStored();
        if (block.timestamp >= periodFinish) {
            rewardRate = reward.div(DURATION);
        } else {
            uint256 remaining = periodFinish.sub(block.timestamp);
            uint256 leftover = remaining.mul(rewardRate);
            rewardRate = reward.add(leftover).div(DURATION);
        }
        emit RewardAdded(reward);
    }

    // Returns the users current multiplier level
    function getLevel(address account) external view returns (uint256) {
        return boostLevel[account];
    }

    // Return the amount spent on multipliers, used for subtracting for future purchases.
    function getSpent(address account) external view returns (uint256) {
        return spentMultiplierTokens[account];
    }

    // Calculate the cost for purchasing a boost.
    function calculateCost(uint256 level) public pure returns (uint256) {
        if (level == 1) {
            return boostLevelOneCost;
        } else if (level == 2) {
            return boostLevelTwoCost;
        } else if (level == 3) {
            return boostLevelThreeCost;
        } else if (level == 4) {
            return boostLevelFourCost;
        }
    }

    // Purchase a multiplier level, same level cannot be purchased twice.
    function purchase(uint256 level) external {
        require(
            boostLevel[msg.sender] <= level,
            "Cannot downgrade level or same level"
        );
        uint256 cost = calculateCost(level);
        // Cost will be reduced by the amount already spent on multipliers.
        uint256 finalCost = cost.sub(spentMultiplierTokens[msg.sender]);

        // Transfer tokens to the contract
        multiplierToken.safeTransferFrom(msg.sender, address(this), finalCost);

        // Update balances and level
        multiplierTokenDevFund = multiplierTokenDevFund.add(finalCost);
        spentMultiplierTokens[msg.sender] = spentMultiplierTokens[msg.sender]
            .add(finalCost);
        boostLevel[msg.sender] = level;

        // If user has staked balances, then set their new accounting balance
        if (_balances[msg.sender] > 0) {
            // Get the previous accounting balance
            uint256 prevBalancesAccounting = _balancesAccounting[msg.sender];
            // Get the new multiplier
            uint256 accTotalMultiplier = getTotalMultiplier(msg.sender);
            // Calculate new accounting  balance
            uint256 newBalancesAccounting = _balances[msg.sender]
                .mul(accTotalMultiplier)
                .div(1e18)
                .sub(_balances[msg.sender]);
            // Set the accounting balance
            _balancesAccounting[msg.sender] = newBalancesAccounting;
            // Get the difference for adjusting the total accounting balance
            uint256 diffBalancesAccounting = newBalancesAccounting.sub(
                prevBalancesAccounting
            );
            // Adjust the global accounting balance.
            _totalSupplyAccounting = _totalSupplyAccounting.add(
                diffBalancesAccounting
            );
        }

        emit Boost(level);
    }

    // Returns the multiplier for user.
    function getTotalMultiplier(address account) public view returns (uint256) {
        uint256 boostMultiplier = 0;
        if (boostLevel[account] == 1) {
            boostMultiplier = FivePercentBonus;
        } else if (boostLevel[account] == 2) {
            boostMultiplier = TwentyPercentBonus;
        } else if (boostLevel[account] == 3) {
            boostMultiplier = FourtyPercentBonus;
        } else if (boostLevel[account] == 4) {
            boostMultiplier = HundredPercentBonus;
        }
        return boostMultiplier.add(1 * 10**18);
    }

    // Distributes the dev fund for accounts
    function distributeDevFund() public override {
        uint256 totalMulitplierDistributionAmount = multiplierTokenDevFund;
        multiplierTokenDevFund = 0;
        // Distribute multiplier dev fund according to percentages
        for (uint256 i = 0; i < devCount; i++) {
            uint256 devPercentage = devAllocations[devIDs[i]];
            uint256 allocation = totalMulitplierDistributionAmount
                .mul(devPercentage)
                .div(100);
            if (allocation > 0) {
                multiplierToken.safeTransfer(devIDs[i], allocation);
            }
        }
        // Distribute the staking token rewards
        super.distributeDevFund();
    }

    // Ejects any remaining tokens from the pool.
    // Callable only after the pool has started and the pools reward distribution period has finished.
    function eject() external onlyOwner {
        require(
            startTime < block.timestamp && block.timestamp >= periodFinish,
            "Cannot eject before period finishes or pool has started"
        );
        uint256 currBalance = rewardToken.balanceOf(address(this));
        rewardToken.safeTransfer(msg.sender, currBalance);
    }

    // Forcefully retire a pool
    // Only sets the period finish to 0
    // This will prevent more rewards from being disbursed
    function kill() external onlyOwner {
        periodFinish = block.timestamp;
    }

    function updateRewardPerTokenStored() internal {
        rewardPerTokenStored = rewardPerToken();
        lastUpdateTime = lastTimeRewardApplicable();
    }

    function updateReward(address account) internal {
        updateRewardPerTokenStored();
        rewards[account] = earned(account);
        userRewardPerTokenPaid[account] = rewardPerTokenStored;
    }
}
/*
 ______                                          __    __
 / ________ __________ ___  ____ _____ ____  ____/ ____/ ____  ____
 / /_  / __ `/ ___/ __ `__ \/ __ `/ __ `/ _ \/ __  / __  / __ \/ __ \
 / __/ / /_/ / /  / / / / / / /_/ / /_/ /  __/ /_/ / /_/ / /_/ / / / /
 /_/    \__,_/_/  /_/ /_/ /_/\__,_/\__, /\___/\__,_/\__,_/\____/_/ /_/
 /____/
 
 *   FARMAFINANCE: MintablePool.sol
 *   https://farma.finance
 *   telegram: TBA
 */
function notifyRewardAmountWithoutUpdateTime(uint256 reward)
    external
    onlyOwner
{
    updateRewardPerTokenStored();
    if (block.timestamp >= periodFinish) {
        rewardRate = reward.div(DURATION);
    } else {
        uint256 remaining = periodFinish.sub(block.timestamp);
        uint256 leftover = remaining.mul(rewardRate);
        rewardRate = reward.add(leftover).div(DURATION);
    }
    emit RewardAdded(reward);
}

// Notify the reward amount without updating time;