Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: BUSL-1.1
pragma solidity ^0.8.17;

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

    function getTotalShares() external view returns (uint256);

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

    function sharesOf(address _account) external view returns (uint256);

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

    function approve(address _spender, uint256 _amount) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);

    function transferShares(
        address _recipient,
        uint256 _sharesAmount
    ) external returns (uint256);

    function getSharesByMintedEUSD(
        uint256 _EUSDAmount
    ) external view returns (uint256);

    function getMintedEUSDByShares(
        uint256 _sharesAmount
    ) external view returns (uint256);

    function mint(
        address _recipient,
        uint256 _mintAmount
    ) external returns (uint256 newTotalShares);

    function burnShares(
        address _account,
        uint256 burnAmount
    ) external returns (uint256 newTotalShares);

    function burn(
        address _account,
        uint256 burnAmount
    ) external returns (uint256 newTotalShares);

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

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 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://consensys.net/diligence/blog/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/v0.8.0/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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or 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 {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: BUSL-1.1

pragma solidity ^0.8.17;

import "../interfaces/IEUSD.sol";
import "./base/LybraEUSDVaultBase.sol";

interface Ilido {
    function submit(address _referral) external payable returns (uint256 StETH);
}

contract LybraStETHVault is LybraEUSDVaultBase {
    // Currently, the official rebase time for Lido is between 12PM to 13PM UTC.
    uint256 public lidoRebaseTime = 12 hours;

    // stETH = 0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84
    // oracle = 0x4c517D4e2C851CA76d7eC94B805269Df0f2201De
    constructor(address _stETH, address _oracle, address _config) LybraEUSDVaultBase(_stETH, _oracle, _config) {
    }

    /**
     * @notice Sets the rebase time for Lido based on the actual situation.
     * This function can only be called by an address with the ADMIN role.
     */
    function setLidoRebaseTime(uint256 _time) external {
        require(configurator.hasRole(keccak256("ADMIN"), msg.sender), "NA");
        lidoRebaseTime = _time;
    }

    /**
     * @notice Allows users to deposit ETH to mint eUSD.
     * ETH is directly deposited into Lido and converted to stETH.
     * @param mintAmount The amount of eUSD to mint.
     * Requirements:
     * The deposited amount of ETH must be greater than or equal to 1 ETH.
     */
    function depositEtherToMint(uint256 mintAmount) external payable override {
        require(msg.value >= 1 ether, "DNL");
        //convert to steth
        uint256 sharesAmount = Ilido(address(collateralAsset)).submit{value: msg.value}(address(configurator));
        require(sharesAmount != 0, "ZERO_DEPOSIT");

        totalDepositedAsset += msg.value;
        depositedAsset[msg.sender] += msg.value;
        depositedTime[msg.sender] = block.timestamp;

        if (mintAmount > 0) {
            _mintEUSD(msg.sender, msg.sender, mintAmount, getAssetPrice());
        }

        emit DepositEther(msg.sender, address(collateralAsset), msg.value, msg.value, block.timestamp);
    }

    /**
     * @notice When stETH balance increases through LSD or other reasons, the excess income is sold for eUSD, allocated to eUSD holders through rebase mechanism.
     * Emits a `LSDValueCaptured` event.
     *
     * *Requirements:
     * - stETH balance in the contract cannot be less than totalDepositedAsset after exchange.
     * @dev Income is used to cover accumulated Service Fee first.
     */
    function excessIncomeDistribution(uint256 stETHAmount) external override {
        uint256 excessAmount = collateralAsset.balanceOf(address(this)) - totalDepositedAsset;
        require(excessAmount != 0 && stETHAmount != 0, "Only LSD excess income can be exchanged");
        uint256 realAmount = stETHAmount > excessAmount ? excessAmount : stETHAmount;
        uint256 dutchAuctionDiscountPrice = getDutchAuctionDiscountPrice();
        uint256 payAmount = realAmount * getAssetPrice() * dutchAuctionDiscountPrice / 10_000 / 1e18;

        uint256 income = feeStored + _newFee();
        if (payAmount > income) {
            bool success = EUSD.transferFrom(msg.sender, address(configurator), income);
            require(success, "TF");

            try configurator.distributeRewards() {} catch {}

            uint256 sharesAmount = EUSD.getSharesByMintedEUSD(payAmount - income);
            if (sharesAmount == 0) {
                //eUSD totalSupply is 0: assume that shares correspond to eUSD 1-to-1
                sharesAmount = (payAmount - income);
            }
            //Income is distributed to LBR staker.
            EUSD.burnShares(msg.sender, sharesAmount);
            feeStored = 0;
            emit FeeDistribution(address(configurator), income, block.timestamp);
        } else {
            bool success = EUSD.transferFrom(msg.sender, address(configurator), payAmount);
            require(success, "TF");
            try configurator.distributeRewards() {} catch {}
            feeStored = income - payAmount;
            emit FeeDistribution(address(configurator), payAmount, block.timestamp);
        }

        lastReportTime = block.timestamp;
        collateralAsset.transfer(msg.sender, realAmount);
        emit LSDValueCaptured(realAmount, payAmount, dutchAuctionDiscountPrice, block.timestamp);
    }

    /**
     * @notice Reduces the discount for the issuance of additional tokens based on the rebase time using the Dutch auction method.
     * The specific rule is that the discount rate increases by 1% every 30 minutes after the rebase occurs.
     */
    function getDutchAuctionDiscountPrice() public view returns (uint256) {
        uint256 time = (block.timestamp - lidoRebaseTime) % 1 days;
        if (time < 30 minutes) return 10_000;
        return 10_000 - (time / 30 minutes - 1) * 100;
    }

    function getAssetPrice() public override returns (uint256) {
        return _etherPrice();
    }
    function getAsset2EtherExchangeRate() external view override returns (uint256) {
        return 1e18;
    }
}

// SPDX-License-Identifier: BUSL-1.1

pragma solidity ^0.8.17;

interface Iconfigurator {
    function mintVault(address pool) external view returns(bool);
    function mintVaultMaxSupply(address pool) external view returns(uint256);
    function vaultMintPaused(address pool) external view returns(bool);
    function vaultBurnPaused(address pool) external view returns(bool);
    function tokenMiner(address pool) external view returns(bool);
    function getSafeCollateralRatio(address pool) external view returns(uint256);
    function getBadCollateralRatio(address pool) external view returns(uint256);
    function getVaultWeight(address pool) external view returns (uint256);
    function vaultMintFeeApy(address pool) external view returns(uint256);
    function vaultKeeperRatio(address pool) external view returns(uint256);
    function redemptionFee() external view returns(uint256);
    function getEUSDAddress() external view returns(address);
    function peUSD() external view returns(address);
    function eUSDMiningIncentives() external view returns(address);
    function getProtocolRewardsPool() external view returns(address);
    function flashloanFee() external view returns(uint256);
    function getEUSDMaxLocked() external view returns (uint256);
    function stableToken() external view returns (address);
    function isRedemptionProvider(address user) external view returns (bool);
    function becomeRedemptionProvider(bool _bool) external;
    function refreshMintReward(address user) external;
    function distributeRewards() external;
    function hasRole(bytes32 role, address account) external view returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

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

// SPDX-License-Identifier: BUSL-1.1

pragma solidity ^0.8.17;

import "../../interfaces/IEUSD.sol";
import "../../interfaces/Iconfigurator.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

interface IPriceFeed {
    function fetchPrice() external returns (uint256);
}

abstract contract LybraEUSDVaultBase {
    using SafeERC20 for IERC20;
    IEUSD public immutable EUSD;
    IERC20 public immutable collateralAsset;
    Iconfigurator public immutable configurator;
    uint256 public constant badCollateralRatio = 150 * 1e18;
    IPriceFeed immutable etherOracle;

    uint256 public totalDepositedAsset;
    uint256 public lastReportTime;
    uint256 poolTotalCirculation;

    mapping(address => uint256) public depositedAsset;
    mapping(address => uint256) borrowed;
    uint256 public feeStored;
    mapping(address => uint256) depositedTime;

    event DepositEther(address indexed onBehalfOf, address asset, uint256 etherAmount, uint256 assetAmount, uint256 timestamp);

    event DepositAsset(address indexed onBehalfOf, address asset, uint256 amount, uint256 timestamp);

    event WithdrawAsset(address indexed sponsor, address asset, address indexed onBehalfOf, uint256 amount, uint256 timestamp);
    event Mint(address indexed sponsor, address indexed onBehalfOf, uint256 amount, uint256 timestamp);
    event Burn(address indexed sponsor, address indexed onBehalfOf, uint256 amount, uint256 timestamp);
    event LiquidationRecord(address indexed provider, address indexed keeper, address indexed onBehalfOf, uint256 eusdamount, uint256 liquidateEtherAmount, uint256 keeperReward, bool superLiquidation, uint256 timestamp);
    event LSDValueCaptured(uint256 stETHAdded, uint256 payoutEUSD, uint256 discountRate, uint256 timestamp);
    event RigidRedemption(address indexed caller, address indexed provider, uint256 eusdAmount, uint256 collateralAmount, uint256 timestamp);
    event FeeDistribution(address indexed feeAddress, uint256 feeAmount, uint256 timestamp);

    //etherOracle = 0x4c517D4e2C851CA76d7eC94B805269Df0f2201De
    constructor(address _collateralAsset, address _etherOracle, address _configurator) {
        collateralAsset = IERC20(_collateralAsset);
        configurator = Iconfigurator(_configurator);
        EUSD = IEUSD(configurator.getEUSDAddress());
        etherOracle = IPriceFeed(_etherOracle);
    }

    /**
     * @notice Allowing direct deposits of ETH, the pool may convert it into the corresponding collateral during the implementation.
     * While depositing, it is possible to simultaneously mint eUSD for oneself.
     * Emits a `DepositEther` event.
     *
     * Requirements:
     * - `mintAmount` Send 0 if doesn't mint eUSD
     * - msg.value Must be higher than 0.
     */
    function depositEtherToMint(uint256 mintAmount) external payable virtual;

    /**
     * @notice Deposit collateral and allow minting eUSD for oneself.
     * Emits a `DepositAsset` event.
     *
     * Requirements:
     * - `assetAmount` Must be higher than 1e18.
     * - `mintAmount` Send 0 if doesn't mint eUSD
     */
    function depositAssetToMint(uint256 assetAmount, uint256 mintAmount) external virtual {
        require(assetAmount >= 1 ether, "Deposit should not be less than 1 stETH.");
        collateralAsset.safeTransferFrom(msg.sender, address(this), assetAmount);
        totalDepositedAsset += assetAmount;
        depositedAsset[msg.sender] += assetAmount;
        depositedTime[msg.sender] = block.timestamp;

        if (mintAmount > 0) {
            _mintEUSD(msg.sender, msg.sender, mintAmount, getAssetPrice());
        }
        emit DepositAsset(msg.sender, address(collateralAsset), assetAmount, block.timestamp);
    }

    /**
     * @notice Withdraw collateral assets to an address
     * Emits a `WithdrawEther` event.
     *
     * Requirements:
     * - `onBehalfOf` cannot be the zero address.
     * - `amount` Must be higher than 0.
     *
     * @dev Withdraw stETH. Check user’s collateral ratio after withdrawal, should be higher than `safeCollateralRatio`
     */
    function withdraw(address onBehalfOf, uint256 amount) external virtual {
        require(onBehalfOf != address(0), "TZA");
        require(amount != 0, "ZERO_WITHDRAW");
        require(depositedAsset[msg.sender] >= amount, "Withdraw amount exceeds deposited amount.");
        totalDepositedAsset -= amount;
        depositedAsset[msg.sender] -= amount;

        uint256 withdrawal = checkWithdrawal(msg.sender, amount);

        collateralAsset.safeTransfer(onBehalfOf, withdrawal);
        if (borrowed[msg.sender] > 0) {
            _checkHealth(msg.sender, getAssetPrice());
        }
        emit WithdrawAsset(msg.sender, address(collateralAsset), onBehalfOf, withdrawal, block.timestamp);
    }

    function checkWithdrawal(address user, uint256 amount) public view returns (uint256 withdrawal) {
        withdrawal = block.timestamp - 3 days >= depositedTime[user] ? amount : (amount * 999) / 1000;
    }

    /**
     * @notice The mint amount number of eUSD is minted to the address
     * Emits a `Mint` event.
     *
     * Requirements:
     * - `onBehalfOf` cannot be the zero address.
     */
    function mint(address onBehalfOf, uint256 amount) external {
        require(onBehalfOf != address(0), "MINT_TO_THE_ZERO_ADDRESS");
        require(amount != 0, "ZERO_MINT");
        _mintEUSD(msg.sender, onBehalfOf, amount, getAssetPrice());
    }

    /**
     * @notice Burn the amount of eUSD and payback the amount of minted eUSD
     * Emits a `Burn` event.
     * Requirements:
     * - `onBehalfOf` cannot be the zero address.
     * - `amount` Must be higher than 0.
     * @dev Calling the internal`_repay`function.
     */
    function burn(address onBehalfOf, uint256 amount) external {
        require(onBehalfOf != address(0), "BURN_TO_THE_ZERO_ADDRESS");
        _repay(msg.sender, onBehalfOf, amount);
    }

    /**
     * @notice Keeper liquidates borrowers whose collateral ratio is below badCollateralRatio, using eUSD provided by Liquidation Provider.
     *
     * Requirements:
     * - onBehalfOf Collateral Ratio should be below badCollateralRatio
     * - collateralAmount should be less than 50% of collateral
     * - provider should authorize Lybra to utilize eUSD
     * @dev After liquidation, borrower's debt is reduced by collateralAmount * etherPrice, providers and keepers can receive up to an additional 10% liquidation reward. 
     */
    function liquidation(address provider, address onBehalfOf, uint256 assetAmount) external virtual {
        uint256 assetPrice = getAssetPrice();
        uint256 onBehalfOfCollateralRatio = (depositedAsset[onBehalfOf] * assetPrice * 100) / borrowed[onBehalfOf];
        require(onBehalfOfCollateralRatio < badCollateralRatio, "Borrowers collateral ratio should below badCollateralRatio");

        require(assetAmount * 2 <= depositedAsset[onBehalfOf], "a max of 50% collateral can be liquidated");
        require(EUSD.allowance(provider, address(this)) != 0 || msg.sender == provider, "provider should authorize to provide liquidation eUSD");
        uint256 eusdAmount = (assetAmount * assetPrice) / 1e18;

        _repay(provider, onBehalfOf, eusdAmount);
        uint256 reducedAsset = assetAmount;

        if(onBehalfOfCollateralRatio > 1e20 && onBehalfOfCollateralRatio < 11e19) {
            reducedAsset = assetAmount * onBehalfOfCollateralRatio / 1e20;
        }
        if(onBehalfOfCollateralRatio >= 11e19) {
            reducedAsset = assetAmount * 11 / 10;
        }
        totalDepositedAsset -= reducedAsset;
        depositedAsset[onBehalfOf] -= reducedAsset;

        uint256 reward2keeper;
        uint256 keeperRatio = configurator.vaultKeeperRatio(address(this));
        if (msg.sender != provider && onBehalfOfCollateralRatio >= 1e20 + keeperRatio * 1e18) {
            reward2keeper = assetAmount * keeperRatio / 100;
            collateralAsset.safeTransfer(msg.sender, reward2keeper);
        }
        collateralAsset.safeTransfer(provider, reducedAsset - reward2keeper);

        emit LiquidationRecord(provider, msg.sender, onBehalfOf, eusdAmount, reducedAsset, reward2keeper, false, block.timestamp);
    }

    /**
     * @notice When overallCollateralRatio is below badCollateralRatio, borrowers with collateralRatio below 125% could be fully liquidated.
     * Emits a `LiquidationRecord` event.
     *
     * Requirements:
     * - Current overallCollateralRatio should be below badCollateralRatio
     * - `onBehalfOf`collateralRatio should be below 125%
     * @dev After Liquidation, borrower's debt is reduced by collateralAmount * etherPrice, deposit is reduced by collateralAmount * borrower's collateralRatio. Keeper gets a liquidation reward of `keeperRatio / borrower's collateralRatio
     */
    function superLiquidation(address provider, address onBehalfOf, uint256 assetAmount) external virtual {
        uint256 assetPrice = getAssetPrice();
        require((totalDepositedAsset * assetPrice * 100) / poolTotalCirculation < badCollateralRatio, "overallCollateralRatio should below 150%");
        uint256 onBehalfOfCollateralRatio = (depositedAsset[onBehalfOf] * assetPrice * 100) / borrowed[onBehalfOf];
        require(onBehalfOfCollateralRatio < 125 * 1e18, "borrowers collateralRatio should below 125%");
        require(assetAmount <= depositedAsset[onBehalfOf], "total of collateral can be liquidated at most");
        uint256 eusdAmount = (assetAmount * assetPrice) / 1e18;
        if (onBehalfOfCollateralRatio >= 1e20) {
            eusdAmount = (eusdAmount * 1e20) / onBehalfOfCollateralRatio;
        }
        require(EUSD.allowance(provider, address(this)) != 0 || msg.sender == provider, "provider should authorize to provide liquidation eUSD");

        _repay(provider, onBehalfOf, eusdAmount);

        totalDepositedAsset -= assetAmount;
        depositedAsset[onBehalfOf] -= assetAmount;
        uint256 reward2keeper;
        if (msg.sender != provider && onBehalfOfCollateralRatio >= 1e20 + configurator.vaultKeeperRatio(address(this)) * 1e18) {
            reward2keeper = ((assetAmount * configurator.vaultKeeperRatio(address(this))) * 1e18) / onBehalfOfCollateralRatio;
            collateralAsset.safeTransfer(msg.sender, reward2keeper);
        }
        collateralAsset.safeTransfer(provider, assetAmount - reward2keeper);

        emit LiquidationRecord(provider, msg.sender, onBehalfOf, eusdAmount, assetAmount, reward2keeper, true, block.timestamp);
    }

    /**
     * @notice When stETH balance increases through LSD or other reasons, the excess income is sold for eUSD, allocated to eUSD holders through rebase mechanism.
     * Emits a `LSDistribution` event.
     *
     * *Requirements:
     * - stETH balance in the contract cannot be less than totalDepositedAsset after exchange.
     * @dev Income is used to cover accumulated Service Fee first.
     */
    function excessIncomeDistribution(uint256 payAmount) external virtual;

    /**
     * @notice Choose a Redemption Provider, Rigid Redeem `eusdAmount` of eUSD and get 1:1 value of collateral
     * Emits a `RigidRedemption` event.
     *
     * *Requirements:
     * - `provider` must be a Redemption Provider
     * - `provider`debt must equal to or above`eusdAmount`
     * @dev Service Fee for rigidRedemption `redemptionFee` is set to 0.5% by default, can be revised by DAO.
     */
    function rigidRedemption(address provider, uint256 eusdAmount, uint256 minReceiveAmount) external virtual {
        require(provider != msg.sender, "CBS");
        require(configurator.isRedemptionProvider(provider), "provider is not a RedemptionProvider");
        require(borrowed[provider] >= eusdAmount, "eusdAmount cannot surpass providers debt");
        uint256 assetPrice = getAssetPrice();
        uint256 providerCollateralRatio = (depositedAsset[provider] * assetPrice * 100) / borrowed[provider];
        require(providerCollateralRatio >= 100 * 1e18, "The provider's collateral ratio should be not less than 100%.");
        _repay(msg.sender, provider, eusdAmount);
        uint256 collateralAmount = eusdAmount * 1e18 * (10_000 - configurator.redemptionFee()) / assetPrice / 10_000;
        uint256 sendAmount = checkWithdrawal(provider, collateralAmount);
        require(sendAmount >= minReceiveAmount, "EL");
        depositedAsset[provider] -= collateralAmount;
        totalDepositedAsset -= collateralAmount;
        collateralAsset.safeTransfer(msg.sender, sendAmount);
        emit RigidRedemption(msg.sender, provider, eusdAmount, sendAmount, block.timestamp);
    }

    /**
     * @notice Mints eUSD tokens for a user.
     * @param _provider The provider's address.
     * @param _onBehalfOf The user's address.
     * @param _mintAmount The amount of eUSD tokens to be minted.
     * @param _assetPrice The current collateral asset price.
     * @dev Mints eUSD tokens for the specified user, updates the total supply and borrowed balance,
     * refreshes the mint reward for the provider, checks the health of the provider,
     * and emits a Mint event.
     * Requirements:
     * The total supply plus mint amount must not exceed the maximum supply allowed for the vault.
     * The provider must have sufficient borrowing capacity to mint the specified amount.
     */
    function _mintEUSD(address _provider, address _onBehalfOf, uint256 _mintAmount, uint256 _assetPrice) internal virtual {
        require(poolTotalCirculation + _mintAmount <= configurator.mintVaultMaxSupply(address(this)), "ESL");
        configurator.refreshMintReward(_provider);
        borrowed[_provider] += _mintAmount;

        EUSD.mint(_onBehalfOf, _mintAmount);
        _saveReport();
        poolTotalCirculation += _mintAmount;
        _checkHealth(_provider, _assetPrice);
        emit Mint(msg.sender, _onBehalfOf, _mintAmount, block.timestamp);
    }

    /**
     * @notice Burn _provideramount eUSD to payback minted eUSD for _onBehalfOf.
     *
     * @dev Refresh LBR reward before reducing providers debt. Refresh Lybra generated service fee before reducing totalEUSDCirculation.
     */
    function _repay(address _provider, address _onBehalfOf, uint256 _amount) internal virtual {
        uint256 amount = borrowed[_onBehalfOf] >= _amount ? _amount : borrowed[_onBehalfOf];

        EUSD.burn(_provider, amount);
        configurator.refreshMintReward(_onBehalfOf);

        borrowed[_onBehalfOf] -= amount;
        _saveReport();
        poolTotalCirculation -= amount;
        emit Burn(_provider, _onBehalfOf, amount, block.timestamp);
    }

    /**
     * @dev Get USD value of current collateral asset and minted eUSD through price oracle / Collateral asset USD value must higher than safe Collateral Ratio.
     */
    function _checkHealth(address _user, uint256 _assetPrice) internal view {
        if (((depositedAsset[_user] * _assetPrice * 100) / borrowed[_user]) < configurator.getSafeCollateralRatio(address(this))) revert("collateralRatio is Below safeCollateralRatio");
    }

    function _saveReport() internal {
        feeStored += _newFee();
        lastReportTime = block.timestamp;
    }

    function _newFee() internal view returns (uint256) {
        return (poolTotalCirculation * configurator.vaultMintFeeApy(address(this)) * (block.timestamp - lastReportTime)) / (86_400 * 365) / 10_000;
    }

    /**
     * @dev Return USD value of current ETH through Liquity PriceFeed Contract.
     */
    function _etherPrice() internal returns (uint256) {
        return etherOracle.fetchPrice();
    }

    function getBorrowedOf(address user) external view returns (uint256) {
        return borrowed[user];
    }

    function getPoolTotalCirculation() external view returns (uint256) {
        return poolTotalCirculation;
    }

    function getAsset() external view virtual returns (address) {
        return address(collateralAsset);
    }

    function getVaultType() external pure returns (uint8) {
        return 0;
    }

    function getAssetPrice() public virtual returns (uint256);
    function getAsset2EtherExchangeRate() external view virtual returns (uint256);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.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;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    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));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    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");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
     * 0 before setting it to a non-zero value.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @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).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // 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 cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}