// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

import { AuraMath } from "./AuraMath.sol";
import { IERC20 } from "@openzeppelin/contracts-0.8/token/ERC20/IERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts-0.8/token/ERC20/utils/SafeERC20.sol";

import { IAuraLocker } from "./Interfaces.sol";

/**
 * @title   AuraBalRewardPool
 * @author  Synthetix -> ConvexFinance -> adapted
 * @dev     Modifications from convex-platform/contracts/contracts/BaseRewardPool.sol:
 *            - Delayed start (tokens transferred then delay is enforced before notification)
 *            - One time duration of 14 days
 *            - Remove child reward contracts
 *            - Penalty on claim at 20%
 */
contract AuraBalRewardPool {
    using AuraMath for uint256;
    using SafeERC20 for IERC20;

    IERC20 public immutable rewardToken;
    IERC20 public immutable stakingToken;
    uint256 public constant duration = 14 days;

    address public immutable rewardManager;

    IAuraLocker public auraLocker;
    address public immutable penaltyForwarder;
    uint256 public pendingPenalty = 0;
    uint256 public immutable startTime;

    uint256 public periodFinish = 0;
    uint256 public rewardRate = 0;
    uint256 public lastUpdateTime;
    uint256 public rewardPerTokenStored;
    uint256 private _totalSupply;

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

    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, bool locked);
    event PenaltyForwarded(uint256 amount);
    event Rescued();

    /**
     * @dev Simple constructoor
     * @param _stakingToken  Pool LP token
     * @param _rewardToken   $AURA
     * @param _rewardManager Depositor
     * @param _auraLocker    $AURA lock contract
     * @param _penaltyForwarder Address to which penalties are sent
     */
    constructor(
        address _stakingToken,
        address _rewardToken,
        address _rewardManager,
        address _auraLocker,
        address _penaltyForwarder,
        uint256 _startDelay
    ) {
        require(_stakingToken != _rewardToken && _stakingToken != address(0), "!tokens");
        stakingToken = IERC20(_stakingToken);
        rewardToken = IERC20(_rewardToken);
        require(_rewardManager != address(0), "!manager");
        rewardManager = _rewardManager;
        require(_auraLocker != address(0), "!locker");
        auraLocker = IAuraLocker(_auraLocker);
        require(_penaltyForwarder != address(0), "!forwarder");
        penaltyForwarder = _penaltyForwarder;

        require(_startDelay > 4 days && _startDelay < 2 weeks, "!delay");
        startTime = block.timestamp + _startDelay;
    }

    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    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 AuraMath.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) returns (bool) {
        require(_amount > 0, "RewardPool : Cannot stake 0");

        _totalSupply = _totalSupply.add(_amount);
        _balances[msg.sender] = _balances[msg.sender].add(_amount);

        stakingToken.safeTransferFrom(msg.sender, address(this), _amount);
        emit Staked(msg.sender, _amount);

        return true;
    }

    function stakeAll() external returns (bool) {
        uint256 balance = stakingToken.balanceOf(msg.sender);
        stake(balance);
        return true;
    }

    function stakeFor(address _for, uint256 _amount) public updateReward(_for) returns (bool) {
        require(_amount > 0, "RewardPool : Cannot stake 0");

        //give to _for
        _totalSupply = _totalSupply.add(_amount);
        _balances[_for] = _balances[_for].add(_amount);

        //take away from sender
        stakingToken.safeTransferFrom(msg.sender, address(this), _amount);
        emit Staked(_for, _amount);

        return true;
    }

    function withdraw(
        uint256 amount,
        bool claim,
        bool lock
    ) public updateReward(msg.sender) returns (bool) {
        require(amount > 0, "RewardPool : Cannot withdraw 0");

        _totalSupply = _totalSupply.sub(amount);
        _balances[msg.sender] = _balances[msg.sender].sub(amount);

        stakingToken.safeTransfer(msg.sender, amount);
        emit Withdrawn(msg.sender, amount);

        if (claim) {
            getReward(lock);
        }

        return true;
    }

    /**
     * @dev Gives a staker their rewards
     * @param _lock Lock the rewards? If false, takes a 20% haircut
     */
    function getReward(bool _lock) public updateReward(msg.sender) returns (bool) {
        uint256 reward = rewards[msg.sender];
        if (reward > 0) {
            rewards[msg.sender] = 0;
            if (_lock) {
                rewardToken.safeIncreaseAllowance(address(auraLocker), reward);
                auraLocker.lock(msg.sender, reward);
            } else {
                uint256 penalty = (reward * 3) / 10;
                pendingPenalty += penalty;
                rewardToken.safeTransfer(msg.sender, reward - penalty);
            }
            emit RewardPaid(msg.sender, reward, _lock);
        }
        return true;
    }

    /**
     * @dev Forwards to the penalty forwarder for distro to Aura Lockers
     */
    function forwardPenalty() public {
        uint256 toForward = pendingPenalty;
        pendingPenalty = 0;
        rewardToken.safeTransfer(penaltyForwarder, toForward);
        emit PenaltyForwarded(toForward);
    }

    /**
     * @dev Rescues the reward token provided it hasn't been initiated yet
     */
    function rescueReward() public {
        require(msg.sender == rewardManager, "!rescuer");
        require(block.timestamp < startTime && rewardRate == 0, "Already started");

        uint256 balance = rewardToken.balanceOf(address(this));
        rewardToken.transfer(rewardManager, balance);

        emit Rescued();
    }

    /**
     * @dev Updates the locker address
     */
    function setLocker(address _newLocker) external {
        require(msg.sender == rewardManager, "!auth");
        auraLocker = IAuraLocker(_newLocker);
    }

    /**
     * @dev Called once to initialise the rewards based on balance of stakeToken
     */
    function initialiseRewards() external returns (bool) {
        require(msg.sender == rewardManager || block.timestamp > startTime, "!authorized");
        require(rewardRate == 0, "!one time");

        uint256 rewardsAvailable = rewardToken.balanceOf(address(this));
        require(rewardsAvailable > 0, "!balance");

        rewardRate = rewardsAvailable.div(duration);

        lastUpdateTime = block.timestamp;
        periodFinish = block.timestamp.add(duration);

        emit RewardAdded(rewardsAvailable);

        return true;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

/// @notice A library for performing overflow-/underflow-safe math,
/// updated with awesomeness from of DappHub (https://github.com/dapphub/ds-math).
library AuraMath {
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a - b;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a * b;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return 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);
    }

    function to224(uint256 a) internal pure returns (uint224 c) {
        require(a <= type(uint224).max, "AuraMath: uint224 Overflow");
        c = uint224(a);
    }

    function to128(uint256 a) internal pure returns (uint128 c) {
        require(a <= type(uint128).max, "AuraMath: uint128 Overflow");
        c = uint128(a);
    }

    function to112(uint256 a) internal pure returns (uint112 c) {
        require(a <= type(uint112).max, "AuraMath: uint112 Overflow");
        c = uint112(a);
    }

    function to96(uint256 a) internal pure returns (uint96 c) {
        require(a <= type(uint96).max, "AuraMath: uint96 Overflow");
        c = uint96(a);
    }

    function to32(uint256 a) internal pure returns (uint32 c) {
        require(a <= type(uint32).max, "AuraMath: uint32 Overflow");
        c = uint32(a);
    }
}

/// @notice A library for performing overflow-/underflow-safe addition and subtraction on uint32.
library AuraMath32 {
    function sub(uint32 a, uint32 b) internal pure returns (uint32 c) {
        c = a - b;
    }
}

/// @notice A library for performing overflow-/underflow-safe addition and subtraction on uint112.
library AuraMath112 {
    function add(uint112 a, uint112 b) internal pure returns (uint112 c) {
        c = a + b;
    }

    function sub(uint112 a, uint112 b) internal pure returns (uint112 c) {
        c = a - b;
    }
}

/// @notice A library for performing overflow-/underflow-safe addition and subtraction on uint224.
library AuraMath224 {
    function add(uint224 a, uint224 b) internal pure returns (uint224 c) {
        c = a + b;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

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

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

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

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

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

// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

interface IPriceOracle {
    struct OracleAverageQuery {
        Variable variable;
        uint256 secs;
        uint256 ago;
    }
    enum Variable {
        PAIR_PRICE,
        BPT_PRICE,
        INVARIANT
    }

    function getTimeWeightedAverage(OracleAverageQuery[] memory queries)
        external
        view
        returns (uint256[] memory results);
}

interface IVault {
    enum PoolSpecialization {
        GENERAL,
        MINIMAL_SWAP_INFO,
        TWO_TOKEN
    }
    enum JoinKind {
        INIT,
        EXACT_TOKENS_IN_FOR_BPT_OUT,
        TOKEN_IN_FOR_EXACT_BPT_OUT,
        ALL_TOKENS_IN_FOR_EXACT_BPT_OUT
    }

    enum SwapKind {
        GIVEN_IN,
        GIVEN_OUT
    }

    struct SingleSwap {
        bytes32 poolId;
        SwapKind kind;
        IAsset assetIn;
        IAsset assetOut;
        uint256 amount;
        bytes userData;
    }

    struct FundManagement {
        address sender;
        bool fromInternalBalance;
        address payable recipient;
        bool toInternalBalance;
    }

    struct JoinPoolRequest {
        IAsset[] assets;
        uint256[] maxAmountsIn;
        bytes userData;
        bool fromInternalBalance;
    }

    function getPool(bytes32 poolId) external view returns (address, PoolSpecialization);

    function getPoolTokens(bytes32 poolId)
        external
        view
        returns (
            address[] memory tokens,
            uint256[] memory balances,
            uint256 lastChangeBlock
        );

    function joinPool(
        bytes32 poolId,
        address sender,
        address recipient,
        JoinPoolRequest memory request
    ) external payable;

    function swap(
        SingleSwap memory singleSwap,
        FundManagement memory funds,
        uint256 limit,
        uint256 deadline
    ) external returns (uint256 amountCalculated);

    function exitPool(
        bytes32 poolId,
        address sender,
        address payable recipient,
        ExitPoolRequest memory request
    ) external;

    struct ExitPoolRequest {
        IAsset[] assets;
        uint256[] minAmountsOut;
        bytes userData;
        bool toInternalBalance;
    }
    enum ExitKind {
        EXACT_BPT_IN_FOR_ONE_TOKEN_OUT,
        EXACT_BPT_IN_FOR_TOKENS_OUT,
        BPT_IN_FOR_EXACT_TOKENS_OUT,
        MANAGEMENT_FEE_TOKENS_OUT // for ManagedPool
    }
}

interface IAsset {
    // solhint-disable-previous-line no-empty-blocks
}

interface IAuraLocker {
    function lock(address _account, uint256 _amount) external;

    function checkpointEpoch() external;

    function epochCount() external view returns (uint256);

    function balanceAtEpochOf(uint256 _epoch, address _user) external view returns (uint256 amount);

    function totalSupplyAtEpoch(uint256 _epoch) external view returns (uint256 supply);

    function queueNewRewards(address _rewardsToken, uint256 reward) external;

    function getReward(address _account, bool _stake) external;

    function getReward(address _account) external;
}

interface IExtraRewardsDistributor {
    function addReward(address _token, uint256 _amount) external;
}

interface ICrvDepositorWrapper {
    function getMinOut(uint256, uint256) external view returns (uint256);

    function deposit(
        uint256,
        uint256,
        bool,
        address _stakeAddress
    ) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

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

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

{
  "compilationTarget": {
    "contracts/AuraBalRewardPool.sol": "AuraBalRewardPool"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "none"
  },
  "optimizer": {
    "enabled": true,
    "runs": 800
  },
  "remappings": []
}