pragma solidity ^0.6.0;
pragma experimental ABIEncoderV2;


interface ERC20 {
    function totalSupply() external view returns (uint256 supply);

    function balanceOf(address _owner) external view returns (uint256 balance);

    function transfer(address _to, uint256 _value) external returns (bool success);

    function transferFrom(address _from, address _to, uint256 _value)
        external
        returns (bool success);

    function approve(address _spender, uint256 _value) external returns (bool success);

    function allowance(address _owner, address _spender) external view returns (uint256 remaining);

    function decimals() external view returns (uint256 digits);

    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}  abstract contract GasTokenInterface is ERC20 {
    function free(uint256 value) public virtual returns (bool success);

    function freeUpTo(uint256 value) public virtual returns (uint256 freed);

    function freeFrom(address from, uint256 value) public virtual returns (bool success);

    function freeFromUpTo(address from, uint256 value) public virtual returns (uint256 freed);
}  contract GasBurner {
    // solhint-disable-next-line const-name-snakecase
    GasTokenInterface public constant gasToken = GasTokenInterface(0x0000000000b3F879cb30FE243b4Dfee438691c04);

    modifier burnGas(uint _amount) {
        if (gasToken.balanceOf(address(this)) >= _amount) {
            gasToken.free(_amount);
        }

        _;
    }
}  abstract contract DSProxyInterface {

    /// Truffle wont compile if this isn't commented
    // function execute(bytes memory _code, bytes memory _data)
    //     public virtual
    //     payable
    //     returns (address, bytes32);

    function execute(address _target, bytes memory _data) public virtual payable returns (bytes32);

    function setCache(address _cacheAddr) public virtual payable returns (bool);

    function owner() public virtual returns (address);
}  library Address {
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    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");
    }

    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");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}  library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}  library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(ERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(ERC20 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.
     */
    function safeApprove(ERC20 token, address spender, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(ERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(ERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function _callOptionalReturn(ERC20 token, bytes memory data) private {

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}  contract AdminAuth {

    using SafeERC20 for ERC20;

    address public owner;
    address public admin;

    modifier onlyOwner() {
        require(owner == msg.sender);
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    /// @notice Admin is set by owner first time, after that admin is super role and has permission to change owner
    /// @param _admin Address of multisig that becomes admin
    function setAdminByOwner(address _admin) public {
        require(msg.sender == owner);
        require(admin == address(0));

        admin = _admin;
    }

    /// @notice Admin is able to set new admin
    /// @param _admin Address of multisig that becomes new admin
    function setAdminByAdmin(address _admin) public {
        require(msg.sender == admin);

        admin = _admin;
    }

    /// @notice Admin is able to change owner
    /// @param _owner Address of new owner
    function setOwnerByAdmin(address _owner) public {
        require(msg.sender == admin);

        owner = _owner;
    }

    /// @notice Destroy the contract
    function kill() public onlyOwner {
        selfdestruct(payable(owner));
    }

    /// @notice  withdraw stuck funds
    function withdrawStuckFunds(address _token, uint _amount) public onlyOwner {
        if (_token == 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE) {
            payable(owner).transfer(_amount);
        } else {
            ERC20(_token).safeTransfer(owner, _amount);
        }
    }
}  /// @title Contract with the actuall DSProxy permission calls the automation operations
contract AaveMonitorProxy is AdminAuth {

    using SafeERC20 for ERC20;

    uint public CHANGE_PERIOD;
    address public monitor;
    address public newMonitor;
    address public lastMonitor;
    uint public changeRequestedTimestamp;

    mapping(address => bool) public allowed;

    event MonitorChangeInitiated(address oldMonitor, address newMonitor);
    event MonitorChangeCanceled();
    event MonitorChangeFinished(address monitor);
    event MonitorChangeReverted(address monitor);

    // if someone who is allowed become malicious, owner can't be changed
    modifier onlyAllowed() {
        require(allowed[msg.sender] || msg.sender == owner);
        _;
    }

    modifier onlyMonitor() {
        require (msg.sender == monitor);
        _;
    }

    constructor(uint _changePeriod) public {
        CHANGE_PERIOD = _changePeriod * 1 days;
    }

    /// @notice Only monitor contract is able to call execute on users proxy
    /// @param _owner Address of cdp owner (users DSProxy address)
    /// @param _aaveSaverProxy Address of AaveSaverProxy
    /// @param _data Data to send to AaveSaverProxy
    function callExecute(address _owner, address _aaveSaverProxy, bytes memory _data) public payable onlyMonitor {
        // execute reverts if calling specific method fails
        DSProxyInterface(_owner).execute{value: msg.value}(_aaveSaverProxy, _data);

        // return if anything left
        if (address(this).balance > 0) {
            msg.sender.transfer(address(this).balance);
        }
    }

    /// @notice Allowed users are able to set Monitor contract without any waiting period first time
    /// @param _monitor Address of Monitor contract
    function setMonitor(address _monitor) public onlyAllowed {
        require(monitor == address(0));
        monitor = _monitor;
    }

    /// @notice Allowed users are able to start procedure for changing monitor
    /// @dev after CHANGE_PERIOD needs to call confirmNewMonitor to actually make a change
    /// @param _newMonitor address of new monitor
    function changeMonitor(address _newMonitor) public onlyAllowed {
        require(changeRequestedTimestamp == 0);

        changeRequestedTimestamp = now;
        lastMonitor = monitor;
        newMonitor = _newMonitor;

        emit MonitorChangeInitiated(lastMonitor, newMonitor);
    }

    /// @notice At any point allowed users are able to cancel monitor change
    function cancelMonitorChange() public onlyAllowed {
        require(changeRequestedTimestamp > 0);

        changeRequestedTimestamp = 0;
        newMonitor = address(0);

        emit MonitorChangeCanceled();
    }

    /// @notice Anyone is able to confirm new monitor after CHANGE_PERIOD if process is started
    function confirmNewMonitor() public onlyAllowed {
        require((changeRequestedTimestamp + CHANGE_PERIOD) < now);
        require(changeRequestedTimestamp != 0);
        require(newMonitor != address(0));

        monitor = newMonitor;
        newMonitor = address(0);
        changeRequestedTimestamp = 0;

        emit MonitorChangeFinished(monitor);
    }

    /// @notice Its possible to revert monitor to last used monitor
    function revertMonitor() public onlyAllowed {
        require(lastMonitor != address(0));

        monitor = lastMonitor;

        emit MonitorChangeReverted(monitor);
    }


    /// @notice Allowed users are able to add new allowed user
    /// @param _user Address of user that will be allowed
    function addAllowed(address _user) public onlyAllowed {
        allowed[_user] = true;
    }

    /// @notice Allowed users are able to remove allowed user
    /// @dev owner is always allowed even if someone tries to remove it from allowed mapping
    /// @param _user Address of allowed user
    function removeAllowed(address _user) public onlyAllowed {
        allowed[_user] = false;
    }

    function setChangePeriod(uint _periodInDays) public onlyAllowed {
        require(_periodInDays * 1 days > CHANGE_PERIOD);

        CHANGE_PERIOD = _periodInDays * 1 days;
    }

    /// @notice In case something is left in contract, owner is able to withdraw it
    /// @param _token address of token to withdraw balance
    function withdrawToken(address _token) public onlyOwner {
        uint balance = ERC20(_token).balanceOf(address(this));
        ERC20(_token).safeTransfer(msg.sender, balance);
    }

    /// @notice In case something is left in contract, owner is able to withdraw it
    function withdrawEth() public onlyOwner {
        uint balance = address(this).balance;
        msg.sender.transfer(balance);
    }
}



/// @title Stores subscription information for Aave automatization
contract AaveSubscriptions is AdminAuth {

    struct AaveHolder {
        address user;
        uint128 minRatio;
        uint128 maxRatio;
        uint128 optimalRatioBoost;
        uint128 optimalRatioRepay;
        bool boostEnabled;
    }

    struct SubPosition {
        uint arrPos;
        bool subscribed;
    }

    AaveHolder[] public subscribers;
    mapping (address => SubPosition) public subscribersPos;

    uint public changeIndex;

    event Subscribed(address indexed user);
    event Unsubscribed(address indexed user);
    event Updated(address indexed user);
    event ParamUpdates(address indexed user, uint128, uint128, uint128, uint128, bool);

    /// @dev Called by the DSProxy contract which owns the Aave position
    /// @notice Adds the users Aave poistion in the list of subscriptions so it can be monitored
    /// @param _minRatio Minimum ratio below which repay is triggered
    /// @param _maxRatio Maximum ratio after which boost is triggered
    /// @param _optimalBoost Ratio amount which boost should target
    /// @param _optimalRepay Ratio amount which repay should target
    /// @param _boostEnabled Boolean determing if boost is enabled
    function subscribe(uint128 _minRatio, uint128 _maxRatio, uint128 _optimalBoost, uint128 _optimalRepay, bool _boostEnabled) external {

        // if boost is not enabled, set max ratio to max uint
        uint128 localMaxRatio = _boostEnabled ? _maxRatio : uint128(-1);
        require(checkParams(_minRatio, localMaxRatio), "Must be correct params");

        SubPosition storage subInfo = subscribersPos[msg.sender];

        AaveHolder memory subscription = AaveHolder({
                minRatio: _minRatio,
                maxRatio: localMaxRatio,
                optimalRatioBoost: _optimalBoost,
                optimalRatioRepay: _optimalRepay,
                user: msg.sender,
                boostEnabled: _boostEnabled
            });

        changeIndex++;

        if (subInfo.subscribed) {
            subscribers[subInfo.arrPos] = subscription;

            emit Updated(msg.sender);
            emit ParamUpdates(msg.sender, _minRatio, localMaxRatio, _optimalBoost, _optimalRepay, _boostEnabled);
        } else {
            subscribers.push(subscription);

            subInfo.arrPos = subscribers.length - 1;
            subInfo.subscribed = true;

            emit Subscribed(msg.sender);
        }
    }

    /// @notice Called by the users DSProxy
    /// @dev Owner who subscribed cancels his subscription
    function unsubscribe() external {
        _unsubscribe(msg.sender);
    }

    /// @dev Checks limit if minRatio is bigger than max
    /// @param _minRatio Minimum ratio, bellow which repay can be triggered
    /// @param _maxRatio Maximum ratio, over which boost can be triggered
    /// @return Returns bool if the params are correct
    function checkParams(uint128 _minRatio, uint128 _maxRatio) internal pure returns (bool) {

        if (_minRatio > _maxRatio) {
            return false;
        }

        return true;
    }

    /// @dev Internal method to remove a subscriber from the list
    /// @param _user The actual address that owns the Aave position
    function _unsubscribe(address _user) internal {
        require(subscribers.length > 0, "Must have subscribers in the list");

        SubPosition storage subInfo = subscribersPos[_user];

        require(subInfo.subscribed, "Must first be subscribed");

        address lastOwner = subscribers[subscribers.length - 1].user;

        SubPosition storage subInfo2 = subscribersPos[lastOwner];
        subInfo2.arrPos = subInfo.arrPos;

        subscribers[subInfo.arrPos] = subscribers[subscribers.length - 1];
        subscribers.pop(); // remove last element and reduce arr length

        changeIndex++;
        subInfo.subscribed = false;
        subInfo.arrPos = 0;

        emit Unsubscribed(msg.sender);
    }

    /// @dev Checks if the user is subscribed
    /// @param _user The actual address that owns the Aave position
    /// @return If the user is subscribed
    function isSubscribed(address _user) public view returns (bool) {
        SubPosition storage subInfo = subscribersPos[_user];

        return subInfo.subscribed;
    }

    /// @dev Returns subscribtion information about a user
    /// @param _user The actual address that owns the Aave position
    /// @return Subscription information about the user if exists
    function getHolder(address _user) public view returns (AaveHolder memory) {
        SubPosition storage subInfo = subscribersPos[_user];

        return subscribers[subInfo.arrPos];
    }

    /// @notice Helper method to return all the subscribed CDPs
    /// @return List of all subscribers
    function getSubscribers() public view returns (AaveHolder[] memory) {
        return subscribers;
    }

    /// @notice Helper method for the frontend, returns all the subscribed CDPs paginated
    /// @param _page What page of subscribers you want
    /// @param _perPage Number of entries per page
    /// @return List of all subscribers for that page
    function getSubscribersByPage(uint _page, uint _perPage) public view returns (AaveHolder[] memory) {
        AaveHolder[] memory holders = new AaveHolder[](_perPage);

        uint start = _page * _perPage;
        uint end = start + _perPage;

        end = (end > holders.length) ? holders.length : end;

        uint count = 0;
        for (uint i = start; i < end; i++) {
            holders[count] = subscribers[i];
            count++;
        }

        return holders;
    }

    ////////////// ADMIN METHODS ///////////////////

    /// @notice Admin function to unsubscribe a position
    /// @param _user The actual address that owns the Aave position
    function unsubscribeByAdmin(address _user) public onlyOwner {
        SubPosition storage subInfo = subscribersPos[_user];

        if (subInfo.subscribed) {
            _unsubscribe(_user);
        }
    }
}  contract DSMath {
    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x + y) >= x);
    }

    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x - y) <= x);
    }

    function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require(y == 0 || (z = x * y) / y == x);
    }

    function div(uint256 x, uint256 y) internal pure returns (uint256 z) {
        return x / y;
    }

    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
        return x <= y ? x : y;
    }

    function max(uint256 x, uint256 y) internal pure returns (uint256 z) {
        return x >= y ? x : y;
    }

    function imin(int256 x, int256 y) internal pure returns (int256 z) {
        return x <= y ? x : y;
    }

    function imax(int256 x, int256 y) internal pure returns (int256 z) {
        return x >= y ? x : y;
    }

    uint256 constant WAD = 10**18;
    uint256 constant RAY = 10**27;

    function wmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }

    function rmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }

    function wdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, WAD), y / 2) / y;
    }

    function rdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint256 x, uint256 n) internal pure returns (uint256 z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}  contract DefisaverLogger {
    event LogEvent(
        address indexed contractAddress,
        address indexed caller,
        string indexed logName,
        bytes data
    );

    // solhint-disable-next-line func-name-mixedcase
    function Log(address _contract, address _caller, string memory _logName, bytes memory _data)
        public
    {
        emit LogEvent(_contract, _caller, _logName, _data);
    }
}  abstract contract DSAuthority {
    function canCall(address src, address dst, bytes4 sig) public virtual view returns (bool);
}  contract DSAuthEvents {
    event LogSetAuthority(address indexed authority);
    event LogSetOwner(address indexed owner);
}


contract DSAuth is DSAuthEvents {
    DSAuthority public authority;
    address public owner;

    constructor() public {
        owner = msg.sender;
        emit LogSetOwner(msg.sender);
    }

    function setOwner(address owner_) public auth {
        owner = owner_;
        emit LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_) public auth {
        authority = authority_;
        emit LogSetAuthority(address(authority));
    }

    modifier auth {
        require(isAuthorized(msg.sender, msg.sig));
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, address(this), sig);
        }
    }
}  contract DSNote {
    event LogNote(
        bytes4 indexed sig,
        address indexed guy,
        bytes32 indexed foo,
        bytes32 indexed bar,
        uint256 wad,
        bytes fax
    ) anonymous;

    modifier note {
        bytes32 foo;
        bytes32 bar;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
        }

        emit LogNote(msg.sig, msg.sender, foo, bar, msg.value, msg.data);

        _;
    }
}  abstract contract DSProxy is DSAuth, DSNote {
    DSProxyCache public cache; // global cache for contracts

    constructor(address _cacheAddr) public {
        require(setCache(_cacheAddr));
    }

    // solhint-disable-next-line no-empty-blocks
    receive() external payable {}

    // use the proxy to execute calldata _data on contract _code
    // function execute(bytes memory _code, bytes memory _data)
    //     public
    //     payable
    //     virtual
    //     returns (address target, bytes32 response);

    function execute(address _target, bytes memory _data)
        public
        payable
        virtual
        returns (bytes32 response);

    //set new cache
    function setCache(address _cacheAddr) public virtual payable returns (bool);
}


contract DSProxyCache {
    mapping(bytes32 => address) cache;

    function read(bytes memory _code) public view returns (address) {
        bytes32 hash = keccak256(_code);
        return cache[hash];
    }

    function write(bytes memory _code) public returns (address target) {
        assembly {
            target := create(0, add(_code, 0x20), mload(_code))
            switch iszero(extcodesize(target))
                case 1 {
                    // throw if contract failed to deploy
                    revert(0, 0)
                }
        }
        bytes32 hash = keccak256(_code);
        cache[hash] = target;
    }
}  contract Discount {
    address public owner;
    mapping(address => CustomServiceFee) public serviceFees;

    uint256 constant MAX_SERVICE_FEE = 400;

    struct CustomServiceFee {
        bool active;
        uint256 amount;
    }

    constructor() public {
        owner = msg.sender;
    }

    function isCustomFeeSet(address _user) public view returns (bool) {
        return serviceFees[_user].active;
    }

    function getCustomServiceFee(address _user) public view returns (uint256) {
        return serviceFees[_user].amount;
    }

    function setServiceFee(address _user, uint256 _fee) public {
        require(msg.sender == owner, "Only owner");
        require(_fee >= MAX_SERVICE_FEE || _fee == 0);

        serviceFees[_user] = CustomServiceFee({active: true, amount: _fee});
    }

    function disableServiceFee(address _user) public {
        require(msg.sender == owner, "Only owner");

        serviceFees[_user] = CustomServiceFee({active: false, amount: 0});
    }
}  abstract contract IAToken {
    function redeem(uint256 _amount) external virtual;
}  abstract contract ILendingPool {
    function flashLoan( address payable _receiver, address _reserve, uint _amount, bytes calldata _params) external virtual;
    function deposit(address _reserve, uint256 _amount, uint16 _referralCode) external virtual payable;
	function setUserUseReserveAsCollateral(address _reserve, bool _useAsCollateral) external virtual;
	function borrow(address _reserve, uint256 _amount, uint256 _interestRateMode, uint16 _referralCode) external virtual;
	function repay( address _reserve, uint256 _amount, address payable _onBehalfOf) external virtual payable;
	function swapBorrowRateMode(address _reserve) external virtual;
    function getReserves() external virtual view returns(address[] memory);

    /// @param _reserve underlying token address
    function getReserveData(address _reserve)
        external virtual
        view
        returns (
            uint256 totalLiquidity,               // reserve total liquidity
            uint256 availableLiquidity,           // reserve available liquidity for borrowing
            uint256 totalBorrowsStable,           // total amount of outstanding borrows at Stable rate
            uint256 totalBorrowsVariable,         // total amount of outstanding borrows at Variable rate
            uint256 liquidityRate,                // current deposit APY of the reserve for depositors, in Ray units.
            uint256 variableBorrowRate,           // current variable rate APY of the reserve pool, in Ray units.
            uint256 stableBorrowRate,             // current stable rate APY of the reserve pool, in Ray units.
            uint256 averageStableBorrowRate,      // current average stable borrow rate
            uint256 utilizationRate,              // expressed as total borrows/total liquidity.
            uint256 liquidityIndex,               // cumulative liquidity index
            uint256 variableBorrowIndex,          // cumulative variable borrow index
            address aTokenAddress,                // aTokens contract address for the specific _reserve
            uint40 lastUpdateTimestamp            // timestamp of the last update of reserve data
        );

    /// @param _user users address
    function getUserAccountData(address _user)
        external virtual
        view
        returns (
            uint256 totalLiquidityETH,            // user aggregated deposits across all the reserves. In Wei
            uint256 totalCollateralETH,           // user aggregated collateral across all the reserves. In Wei
            uint256 totalBorrowsETH,              // user aggregated outstanding borrows across all the reserves. In Wei
            uint256 totalFeesETH,                 // user aggregated current outstanding fees in ETH. In Wei
            uint256 availableBorrowsETH,          // user available amount to borrow in ETH
            uint256 currentLiquidationThreshold,  // user current average liquidation threshold across all the collaterals deposited
            uint256 ltv,                          // user average Loan-to-Value between all the collaterals
            uint256 healthFactor                  // user current Health Factor
    );    

    /// @param _reserve underlying token address
    /// @param _user users address
    function getUserReserveData(address _reserve, address _user)
        external virtual
        view
        returns (
            uint256 currentATokenBalance,         // user current reserve aToken balance
            uint256 currentBorrowBalance,         // user current reserve outstanding borrow balance
            uint256 principalBorrowBalance,       // user balance of borrowed asset
            uint256 borrowRateMode,               // user borrow rate mode either Stable or Variable
            uint256 borrowRate,                   // user current borrow rate APY
            uint256 liquidityRate,                // user current earn rate on _reserve
            uint256 originationFee,               // user outstanding loan origination fee
            uint256 variableBorrowIndex,          // user variable cumulative index
            uint256 lastUpdateTimestamp,          // Timestamp of the last data update
            bool usageAsCollateralEnabled         // Whether the user's current reserve is enabled as a collateral
    );

    function getReserveConfigurationData(address _reserve)
        external virtual
        view
        returns (
            uint256 ltv,
            uint256 liquidationThreshold,
            uint256 liquidationBonus,
            address rateStrategyAddress,
            bool usageAsCollateralEnabled,
            bool borrowingEnabled,
            bool stableBorrowRateEnabled,
            bool isActive
    );

    // ------------------ LendingPoolCoreData ------------------------
    function getReserveATokenAddress(address _reserve) public virtual view returns (address);
    function getReserveConfiguration(address _reserve)
        external virtual
        view
        returns (uint256, uint256, uint256, bool);
    function getUserUnderlyingAssetBalance(address _reserve, address _user)
        public virtual
        view
        returns (uint256);

    function getReserveCurrentLiquidityRate(address _reserve)
        public virtual
        view
        returns (uint256);
    function getReserveCurrentVariableBorrowRate(address _reserve)
        public virtual
        view
        returns (uint256);
    function getReserveTotalLiquidity(address _reserve)
        public virtual
        view
        returns (uint256);
    function getReserveAvailableLiquidity(address _reserve)
        public virtual
        view
        returns (uint256);
    function getReserveTotalBorrowsVariable(address _reserve)
        public virtual
        view
        returns (uint256);

    // ---------------- LendingPoolDataProvider ---------------------
    function calculateUserGlobalData(address _user)
        public virtual
        view
        returns (
            uint256 totalLiquidityBalanceETH,
            uint256 totalCollateralBalanceETH,
            uint256 totalBorrowBalanceETH,
            uint256 totalFeesETH,
            uint256 currentLtv,
            uint256 currentLiquidationThreshold,
            uint256 healthFactor,
            bool healthFactorBelowThreshold
        );
}  /**
@title ILendingPoolAddressesProvider interface
@notice provides the interface to fetch the LendingPoolCore address
 */
abstract contract ILendingPoolAddressesProvider {

    function getLendingPool() public virtual view returns (address);
    function getLendingPoolCore() public virtual view returns (address payable);
    function getLendingPoolConfigurator() public virtual view returns (address);
    function getLendingPoolDataProvider() public virtual view returns (address);
    function getLendingPoolParametersProvider() public virtual view returns (address);
    function getTokenDistributor() public virtual view returns (address);
    function getFeeProvider() public virtual view returns (address);
    function getLendingPoolLiquidationManager() public virtual view returns (address);
    function getLendingPoolManager() public virtual view returns (address);
    function getPriceOracle() public virtual view returns (address);
    function getLendingRateOracle() public virtual view returns (address);
}  /************
@title IPriceOracleGetterAave interface
@notice Interface for the Aave price oracle.*/
abstract contract IPriceOracleGetterAave {
    function getAssetPrice(address _asset) external virtual view returns (uint256);
    function getAssetsPrices(address[] calldata _assets) external virtual view returns(uint256[] memory);
    function getSourceOfAsset(address _asset) external virtual view returns(address);
    function getFallbackOracle() external virtual view returns(address);
}  contract BotRegistry is AdminAuth {

    mapping (address => bool) public botList;

    constructor() public {
        botList[0x776B4a13093e30B05781F97F6A4565B6aa8BE330] = true;

        botList[0xAED662abcC4FA3314985E67Ea993CAD064a7F5cF] = true;
        botList[0xa5d330F6619d6bF892A5B87D80272e1607b3e34D] = true;
        botList[0x5feB4DeE5150B589a7f567EA7CADa2759794A90A] = true;
        botList[0x7ca06417c1d6f480d3bB195B80692F95A6B66158] = true;
    }

    function setBot(address _botAddr, bool _state) public onlyOwner {
        botList[_botAddr] = _state;
    }

}  contract AaveHelper is DSMath {

    using SafeERC20 for ERC20;

    address payable public constant WALLET_ADDR = 0x322d58b9E75a6918f7e7849AEe0fF09369977e08;
    address public constant DISCOUNT_ADDR = 0x1b14E8D511c9A4395425314f849bD737BAF8208F;

    uint public constant MANUAL_SERVICE_FEE = 400; // 0.25% Fee
    uint public constant AUTOMATIC_SERVICE_FEE = 333; // 0.3% Fee

    address public constant BOT_REGISTRY_ADDRESS = 0x637726f8b08a7ABE3aE3aCaB01A80E2d8ddeF77B;

	address public constant ETH_ADDR = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    address public constant AAVE_LENDING_POOL_ADDRESSES = 0x24a42fD28C976A61Df5D00D0599C34c4f90748c8;
    uint public constant NINETY_NINE_PERCENT_WEI = 999900000000000000;
    uint16 public constant AAVE_REFERRAL_CODE = 64;

    /// @param _collateralAddress underlying token address
    /// @param _user users address
	function getMaxCollateral(address _collateralAddress, address _user) public view returns (uint256) {
        address lendingPoolAddressDataProvider = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getLendingPoolDataProvider();
        address lendingPoolCoreAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getLendingPoolCore();
        address priceOracleAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getPriceOracle();

        uint256 pow10 = 10 ** (18 - _getDecimals(_collateralAddress));

        // fetch all needed data
        (,uint256 totalCollateralETH, uint256 totalBorrowsETH,,uint256 currentLTV,,,) = ILendingPool(lendingPoolAddressDataProvider).calculateUserGlobalData(_user);
        (,uint256 tokenLTV,,) = ILendingPool(lendingPoolCoreAddress).getReserveConfiguration(_collateralAddress);
        uint256 collateralPrice = IPriceOracleGetterAave(priceOracleAddress).getAssetPrice(_collateralAddress);
        uint256 userTokenBalance = ILendingPool(lendingPoolCoreAddress).getUserUnderlyingAssetBalance(_collateralAddress, _user);
        uint256 userTokenBalanceEth = wmul(userTokenBalance * pow10, collateralPrice);

		// if borrow is 0, return whole user balance
        if (totalBorrowsETH == 0) {
        	return userTokenBalance;
        }

        uint256 maxCollateralEth = div(sub(mul(currentLTV, totalCollateralETH), mul(totalBorrowsETH, 100)), currentLTV);
		/// @dev final amount can't be higher than users token balance
        maxCollateralEth = maxCollateralEth > userTokenBalanceEth ? userTokenBalanceEth : maxCollateralEth;

        // might happen due to wmul precision
        if (maxCollateralEth >= totalCollateralETH) {
        	return wdiv(totalCollateralETH, collateralPrice) / pow10;
        }

        // get sum of all other reserves multiplied with their liquidation thresholds by reversing formula
        uint256 a = sub(wmul(currentLTV, totalCollateralETH), wmul(tokenLTV, userTokenBalanceEth));
        // add new collateral amount multiplied by its threshold, and then divide with new total collateral
        uint256 newLiquidationThreshold = wdiv(add(a, wmul(sub(userTokenBalanceEth, maxCollateralEth), tokenLTV)), sub(totalCollateralETH, maxCollateralEth));

        // if new threshold is lower than first one, calculate new max collateral with newLiquidationThreshold
        if (newLiquidationThreshold < currentLTV) {
        	maxCollateralEth = div(sub(mul(newLiquidationThreshold, totalCollateralETH), mul(totalBorrowsETH, 100)), newLiquidationThreshold);
        	maxCollateralEth = maxCollateralEth > userTokenBalanceEth ? userTokenBalanceEth : maxCollateralEth;
        }



		return wmul(wdiv(maxCollateralEth, collateralPrice) / pow10, NINETY_NINE_PERCENT_WEI);
	}

	/// @param _borrowAddress underlying token address
	/// @param _user users address
	function getMaxBorrow(address _borrowAddress, address _user) public view returns (uint256) {
		address lendingPoolAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getLendingPool();
		address priceOracleAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getPriceOracle();

		(,,,,uint256 availableBorrowsETH,,,) = ILendingPool(lendingPoolAddress).getUserAccountData(_user);

		uint256 borrowPrice = IPriceOracleGetterAave(priceOracleAddress).getAssetPrice(_borrowAddress);

		return wmul(wdiv(availableBorrowsETH, borrowPrice) / (10 ** (18 - _getDecimals(_borrowAddress))), NINETY_NINE_PERCENT_WEI);
	}

    /// @notice Calculates the fee amount
    /// @param _amount Amount that is converted
    /// @param _user Actuall user addr not DSProxy
    /// @param _gasCost Ether amount of gas we are spending for tx
    /// @param _tokenAddr token addr. of token we are getting for the fee
    /// @return feeAmount The amount we took for the fee
    function getFee(uint _amount, address _user, uint _gasCost, address _tokenAddr) internal returns (uint feeAmount) {
        address priceOracleAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getPriceOracle();

        uint fee = MANUAL_SERVICE_FEE;

        if (BotRegistry(BOT_REGISTRY_ADDRESS).botList(tx.origin)) {
            fee = AUTOMATIC_SERVICE_FEE;
        }

        if (Discount(DISCOUNT_ADDR).isCustomFeeSet(_user)) {
            fee = Discount(DISCOUNT_ADDR).getCustomServiceFee(_user);
        }

        feeAmount = (fee == 0) ? 0 : (_amount / fee);

        if (_gasCost != 0) {
            uint256 price = IPriceOracleGetterAave(priceOracleAddress).getAssetPrice(_tokenAddr);

            _gasCost = wmul(_gasCost, price) / (10 ** (18 - _getDecimals(_tokenAddr)));

            feeAmount = add(feeAmount, _gasCost);
        }

        // fee can't go over 20% of the whole amount
        if (feeAmount > (_amount / 5)) {
            feeAmount = _amount / 5;
        }

        if (_tokenAddr == ETH_ADDR) {
            WALLET_ADDR.transfer(feeAmount);
        } else {
            ERC20(_tokenAddr).safeTransfer(WALLET_ADDR, feeAmount);
        }
    }

    /// @notice Calculates the gas cost for transaction
    /// @param _amount Amount that is converted
    /// @param _user Actuall user addr not DSProxy
    /// @param _gasCost Ether amount of gas we are spending for tx
    /// @param _tokenAddr token addr. of token we are getting for the fee
    /// @return gasCost The amount we took for the gas cost
    function getGasCost(uint _amount, address _user, uint _gasCost, address _tokenAddr) internal returns (uint gasCost) {
        address priceOracleAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getPriceOracle();

        if (_gasCost != 0) {
            uint256 price = IPriceOracleGetterAave(priceOracleAddress).getAssetPrice(_tokenAddr);
            _gasCost = wmul(_gasCost, price);

            gasCost = _gasCost;
        }

        // fee can't go over 20% of the whole amount
        if (gasCost > (_amount / 5)) {
            gasCost = _amount / 5;
        }

        if (_tokenAddr == ETH_ADDR) {
            WALLET_ADDR.transfer(gasCost);
        } else {
            ERC20(_tokenAddr).safeTransfer(WALLET_ADDR, gasCost);
        }
    }


    /// @notice Returns the owner of the DSProxy that called the contract
    function getUserAddress() internal view returns (address) {
        DSProxy proxy = DSProxy(payable(address(this)));

        return proxy.owner();
    }

    /// @notice Approves token contract to pull underlying tokens from the DSProxy
    /// @param _tokenAddr Token we are trying to approve
    /// @param _caller Address which will gain the approval
    function approveToken(address _tokenAddr, address _caller) internal {
        if (_tokenAddr != ETH_ADDR) {
            ERC20(_tokenAddr).safeApprove(_caller, 0);
            ERC20(_tokenAddr).safeApprove(_caller, uint256(-1));
        }
    }

    /// @notice Send specific amount from contract to specific user
    /// @param _token Token we are trying to send
    /// @param _user User that should receive funds
    /// @param _amount Amount that should be sent
    function sendContractBalance(address _token, address _user, uint _amount) public {
        if (_amount == 0) return;

        if (_token == ETH_ADDR) {
            payable(_user).transfer(_amount);
        } else {
            ERC20(_token).safeTransfer(_user, _amount);
        }
    }

    function sendFullContractBalance(address _token, address _user) public {
        if (_token == ETH_ADDR) {
            sendContractBalance(_token, _user, address(this).balance);
        } else {
            sendContractBalance(_token, _user, ERC20(_token).balanceOf(address(this)));
        }
    }

    function _getDecimals(address _token) internal view returns (uint256) {
        if (_token == ETH_ADDR) return 18;

        return ERC20(_token).decimals();
    }
}  contract AaveSafetyRatio is AaveHelper {

    function getSafetyRatio(address _user) public view returns(uint256) {
        address lendingPoolAddress = ILendingPoolAddressesProvider(AAVE_LENDING_POOL_ADDRESSES).getLendingPool();
        (,,uint256 totalBorrowsETH,,uint256 availableBorrowsETH,,,) = ILendingPool(lendingPoolAddress).getUserAccountData(_user);

        return wdiv(add(totalBorrowsETH, availableBorrowsETH), totalBorrowsETH);
    }
}  abstract contract TokenInterface {
    function allowance(address, address) public virtual returns (uint256);

    function balanceOf(address) public virtual returns (uint256);

    function approve(address, uint256) public virtual;

    function transfer(address, uint256) public virtual returns (bool);

    function transferFrom(address, address, uint256) public virtual returns (bool);

    function deposit() public virtual payable;

    function withdraw(uint256) public virtual;
}  interface ExchangeInterfaceV2 {
    function sell(address _srcAddr, address _destAddr, uint _srcAmount) external payable returns (uint);

    function buy(address _srcAddr, address _destAddr, uint _destAmount) external payable returns(uint);

    function getSellRate(address _srcAddr, address _destAddr, uint _srcAmount) external view returns (uint);

    function getBuyRate(address _srcAddr, address _destAddr, uint _srcAmount) external view returns (uint);
}  contract ZrxAllowlist is AdminAuth {

    mapping (address => bool) public zrxAllowlist;
    mapping(address => bool) private nonPayableAddrs;

    constructor() public {
        zrxAllowlist[0x6958F5e95332D93D21af0D7B9Ca85B8212fEE0A5] = true;
        zrxAllowlist[0x61935CbDd02287B511119DDb11Aeb42F1593b7Ef] = true;
        zrxAllowlist[0xDef1C0ded9bec7F1a1670819833240f027b25EfF] = true;
        zrxAllowlist[0x080bf510FCbF18b91105470639e9561022937712] = true;

        nonPayableAddrs[0x080bf510FCbF18b91105470639e9561022937712] = true;
    }

    function setAllowlistAddr(address _zrxAddr, bool _state) public onlyOwner {
        zrxAllowlist[_zrxAddr] = _state;
    }

    function isZrxAddr(address _zrxAddr) public view returns (bool) {
        return zrxAllowlist[_zrxAddr];
    }

    function addNonPayableAddr(address _nonPayableAddr) public onlyOwner {
		nonPayableAddrs[_nonPayableAddr] = true;
	}

	function removeNonPayableAddr(address _nonPayableAddr) public onlyOwner {
		nonPayableAddrs[_nonPayableAddr] = false;
	}

	function isNonPayableAddr(address _addr) public view returns(bool) {
		return nonPayableAddrs[_addr];
	}
}  contract SaverExchangeHelper {

    using SafeERC20 for ERC20;

    address public constant KYBER_ETH_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    address public constant WETH_ADDRESS = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;

    address payable public constant WALLET_ID = 0x322d58b9E75a6918f7e7849AEe0fF09369977e08;
    address public constant DISCOUNT_ADDRESS = 0x1b14E8D511c9A4395425314f849bD737BAF8208F;
    address public constant SAVER_EXCHANGE_REGISTRY = 0x25dd3F51e0C3c3Ff164DDC02A8E4D65Bb9cBB12D;

    address public constant ERC20_PROXY_0X = 0x95E6F48254609A6ee006F7D493c8e5fB97094ceF;
    address public constant ZRX_ALLOWLIST_ADDR = 0x4BA1f38427b33B8ab7Bb0490200dAE1F1C36823F;


    function getDecimals(address _token) internal view returns (uint256) {
        if (_token == KYBER_ETH_ADDRESS) return 18;

        return ERC20(_token).decimals();
    }

    function getBalance(address _tokenAddr) internal view returns (uint balance) {
        if (_tokenAddr == KYBER_ETH_ADDRESS) {
            balance = address(this).balance;
        } else {
            balance = ERC20(_tokenAddr).balanceOf(address(this));
        }
    }

    function approve0xProxy(address _tokenAddr, uint _amount) internal {
        if (_tokenAddr != KYBER_ETH_ADDRESS) {
            ERC20(_tokenAddr).safeApprove(address(ERC20_PROXY_0X), _amount);
        }
    }

    function sendLeftover(address _srcAddr, address _destAddr, address payable _to) internal {
        // send back any leftover ether or tokens
        if (address(this).balance > 0) {
            _to.transfer(address(this).balance);
        }

        if (getBalance(_srcAddr) > 0) {
            ERC20(_srcAddr).safeTransfer(_to, getBalance(_srcAddr));
        }

        if (getBalance(_destAddr) > 0) {
            ERC20(_destAddr).safeTransfer(_to, getBalance(_destAddr));
        }
    }

    function sliceUint(bytes memory bs, uint256 start) internal pure returns (uint256) {
        require(bs.length >= start + 32, "slicing out of range");

        uint256 x;
        assembly {
            x := mload(add(bs, add(0x20, start)))
        }

        return x;
    }
}  contract SaverExchangeRegistry is AdminAuth {

	mapping(address => bool) private wrappers;

	constructor() public {
		wrappers[0x880A845A85F843a5c67DB2061623c6Fc3bB4c511] = true;
		wrappers[0x4c9B55f2083629A1F7aDa257ae984E03096eCD25] = true;
		wrappers[0x42A9237b872368E1bec4Ca8D26A928D7d39d338C] = true;
	}

	function addWrapper(address _wrapper) public onlyOwner {
		wrappers[_wrapper] = true;
	}

	function removeWrapper(address _wrapper) public onlyOwner {
		wrappers[_wrapper] = false;
	}

	function isWrapper(address _wrapper) public view returns(bool) {
		return wrappers[_wrapper];
	}
}








contract SaverExchangeCore is SaverExchangeHelper, DSMath {

    // first is empty to keep the legacy order in place
    enum ExchangeType { _, OASIS, KYBER, UNISWAP, ZEROX }

    enum ActionType { SELL, BUY }

    struct ExchangeData {
        address srcAddr;
        address destAddr;
        uint srcAmount;
        uint destAmount;
        uint minPrice;
        address wrapper;
        address exchangeAddr;
        bytes callData;
        uint256 price0x;
    }

    /// @notice Internal method that preforms a sell on 0x/on-chain
    /// @dev Usefull for other DFS contract to integrate for exchanging
    /// @param exData Exchange data struct
    /// @return (address, uint) Address of the wrapper used and destAmount
    function _sell(ExchangeData memory exData) internal returns (address, uint) {

        address wrapper;
        uint swapedTokens;
        bool success;
        uint tokensLeft = exData.srcAmount;

        // if selling eth, convert to weth
        if (exData.srcAddr == KYBER_ETH_ADDRESS) {
            exData.srcAddr = ethToWethAddr(exData.srcAddr);
            TokenInterface(WETH_ADDRESS).deposit.value(exData.srcAmount)();
        }

        // Try 0x first and then fallback on specific wrapper
        if (exData.price0x > 0) {
            approve0xProxy(exData.srcAddr, exData.srcAmount);

            uint ethAmount = getProtocolFee(exData.srcAddr, msg.value, exData.srcAmount);
            (success, swapedTokens, tokensLeft) = takeOrder(exData, ethAmount, ActionType.SELL);

            if (success) {
                wrapper = exData.exchangeAddr;
            }
        }

        // fallback to desired wrapper if 0x failed
        if (!success) {
            swapedTokens = saverSwap(exData, ActionType.SELL);
            wrapper = exData.wrapper;
        }

        require(getBalance(exData.destAddr) >= wmul(exData.minPrice, exData.srcAmount), "Final amount isn't correct");

        // if anything is left in weth, pull it to user as eth
        if (getBalance(WETH_ADDRESS) > 0) {
            TokenInterface(WETH_ADDRESS).withdraw(
                TokenInterface(WETH_ADDRESS).balanceOf(address(this))
            );
        }

        return (wrapper, swapedTokens);
    }

    /// @notice Internal method that preforms a buy on 0x/on-chain
    /// @dev Usefull for other DFS contract to integrate for exchanging
    /// @param exData Exchange data struct
    /// @return (address, uint) Address of the wrapper used and srcAmount
    function _buy(ExchangeData memory exData) internal returns (address, uint) {

        address wrapper;
        uint swapedTokens;
        bool success;

        require(exData.destAmount != 0, "Dest amount must be specified");

        // if selling eth, convert to weth
        if (exData.srcAddr == KYBER_ETH_ADDRESS) {
            exData.srcAddr = ethToWethAddr(exData.srcAddr);
            TokenInterface(WETH_ADDRESS).deposit.value(exData.srcAmount)();
        }

        if (exData.price0x > 0) {
            approve0xProxy(exData.srcAddr, exData.srcAmount);

            uint ethAmount = getProtocolFee(exData.srcAddr, msg.value, exData.srcAmount);
            (success, swapedTokens,) = takeOrder(exData, ethAmount, ActionType.BUY);

            if (success) {
                wrapper = exData.exchangeAddr;
            }
        }

        // fallback to desired wrapper if 0x failed
        if (!success) {
            swapedTokens = saverSwap(exData, ActionType.BUY);
            wrapper = exData.wrapper;
        }

        require(swapedTokens >= exData.destAmount, "Final amount isn't correct");

        // if anything is left in weth, pull it to user as eth
        if (getBalance(WETH_ADDRESS) > 0) {
            TokenInterface(WETH_ADDRESS).withdraw(
                TokenInterface(WETH_ADDRESS).balanceOf(address(this))
            );
        }

        return (wrapper, getBalance(exData.destAddr));
    }

    /// @notice Takes order from 0x and returns bool indicating if it is successful
    /// @param _exData Exchange data
    /// @param _ethAmount Ether fee needed for 0x order
    function takeOrder(
        ExchangeData memory _exData,
        uint256 _ethAmount,
        ActionType _type
    ) private returns (bool success, uint256, uint256) {

        // write in the exact amount we are selling/buing in an order
        if (_type == ActionType.SELL) {
            writeUint256(_exData.callData, 36, _exData.srcAmount);
        } else {
            writeUint256(_exData.callData, 36, _exData.destAmount);
        }

        if (ZrxAllowlist(ZRX_ALLOWLIST_ADDR).isNonPayableAddr(_exData.exchangeAddr)) {
            _ethAmount = 0;
        }

        uint256 tokensBefore = getBalance(_exData.destAddr);

        if (ZrxAllowlist(ZRX_ALLOWLIST_ADDR).isZrxAddr(_exData.exchangeAddr)) {
            (success, ) = _exData.exchangeAddr.call{value: _ethAmount}(_exData.callData);
        } else {
            success = false;
        }

        uint256 tokensSwaped = 0;
        uint256 tokensLeft = _exData.srcAmount;

        if (success) {
            // check to see if any _src tokens are left over after exchange
            tokensLeft = getBalance(_exData.srcAddr);

            // convert weth -> eth if needed
            if (_exData.destAddr == KYBER_ETH_ADDRESS) {
                TokenInterface(WETH_ADDRESS).withdraw(
                    TokenInterface(WETH_ADDRESS).balanceOf(address(this))
                );
            }

            // get the current balance of the swaped tokens
            tokensSwaped = getBalance(_exData.destAddr) - tokensBefore;
        }

        return (success, tokensSwaped, tokensLeft);
    }

    /// @notice Calls wraper contract for exchage to preform an on-chain swap
    /// @param _exData Exchange data struct
    /// @param _type Type of action SELL|BUY
    /// @return swapedTokens For Sell that the destAmount, for Buy thats the srcAmount
    function saverSwap(ExchangeData memory _exData, ActionType _type) internal returns (uint swapedTokens) {
        require(SaverExchangeRegistry(SAVER_EXCHANGE_REGISTRY).isWrapper(_exData.wrapper), "Wrapper is not valid");

        uint ethValue = 0;

        ERC20(_exData.srcAddr).safeTransfer(_exData.wrapper, _exData.srcAmount);

        if (_type == ActionType.SELL) {
            swapedTokens = ExchangeInterfaceV2(_exData.wrapper).
                    sell{value: ethValue}(_exData.srcAddr, _exData.destAddr, _exData.srcAmount);
        } else {
            swapedTokens = ExchangeInterfaceV2(_exData.wrapper).
                    buy{value: ethValue}(_exData.srcAddr, _exData.destAddr, _exData.destAmount);
        }
    }

    function writeUint256(bytes memory _b, uint256 _index, uint _input) internal pure {
        if (_b.length < _index + 32) {
            revert("Incorrent lengt while writting bytes32");
        }

        bytes32 input = bytes32(_input);

        _index += 32;

        // Read the bytes32 from array memory
        assembly {
            mstore(add(_b, _index), input)
        }
    }

    /// @notice Converts Kybers Eth address -> Weth
    /// @param _src Input address
    function ethToWethAddr(address _src) internal pure returns (address) {
        return _src == KYBER_ETH_ADDRESS ? WETH_ADDRESS : _src;
    }

    /// @notice Calculates protocol fee 
    /// @param _srcAddr selling token address (if eth should be WETH)
    /// @param _msgValue msg.value in transaction
    /// @param _srcAmount amount we are selling
    function getProtocolFee(address _srcAddr, uint256 _msgValue, uint256 _srcAmount) internal returns(uint256) {
        // if we are not selling ETH msg value is always the protocol fee
        if (_srcAddr != WETH_ADDRESS) return _msgValue;

        // if msg value is larger than srcAmount, that means that msg value is protocol fee + srcAmount, so we subsctract srcAmount from msg value
        // we have an edge case here when protocol fee is higher than selling amount
        if (_msgValue > _srcAmount) return _msgValue - _srcAmount;

        // if msg value is lower than src amount, that means that srcAmount isn't included in msg value, so we return msg value
        return _msgValue;
    }

    function packExchangeData(ExchangeData memory _exData) public pure returns(bytes memory) {
        // splitting in two different bytes and encoding all because of stack too deep in decoding part

        bytes memory part1 = abi.encode(
            _exData.srcAddr,
            _exData.destAddr,
            _exData.srcAmount,
            _exData.destAmount
        );

        bytes memory part2 = abi.encode(
            _exData.minPrice,
            _exData.wrapper,
            _exData.exchangeAddr,
            _exData.callData,
            _exData.price0x
        );


        return abi.encode(part1, part2);
    }

    function unpackExchangeData(bytes memory _data) public pure returns(ExchangeData memory _exData) {
        (
            bytes memory part1,
            bytes memory part2
        ) = abi.decode(_data, (bytes,bytes));

        (
            _exData.srcAddr,
            _exData.destAddr,
            _exData.srcAmount,
            _exData.destAmount
        ) = abi.decode(part1, (address,address,uint256,uint256));

        (
            _exData.minPrice,
            _exData.wrapper,
            _exData.exchangeAddr,
            _exData.callData,
            _exData.price0x
        )
        = abi.decode(part2, (uint256,address,address,bytes,uint256));
    }

    // solhint-disable-next-line no-empty-blocks
    receive() external virtual payable {}
} 










/// @title Contract implements logic of calling boost/repay in the automatic system
contract AaveMonitor is AdminAuth, DSMath, AaveSafetyRatio, GasBurner {

    using SafeERC20 for ERC20;

    enum Method { Boost, Repay }

    uint public REPAY_GAS_TOKEN = 19;
    uint public BOOST_GAS_TOKEN = 19;

    uint public MAX_GAS_PRICE = 200000000000; // 200 gwei

    uint public REPAY_GAS_COST = 2500000;
    uint public BOOST_GAS_COST = 2500000;

    address public constant DEFISAVER_LOGGER = 0x5c55B921f590a89C1Ebe84dF170E655a82b62126;

    AaveMonitorProxy public aaveMonitorProxy;
    AaveSubscriptions public subscriptionsContract;
    address public aaveSaverProxy;

    DefisaverLogger public logger = DefisaverLogger(DEFISAVER_LOGGER);

    modifier onlyApproved() {
        require(BotRegistry(BOT_REGISTRY_ADDRESS).botList(msg.sender), "Not auth bot");
        _;
    }

    /// @param _aaveMonitorProxy Proxy contracts that actually is authorized to call DSProxy
    /// @param _subscriptions Subscriptions contract for Aave positions
    /// @param _aaveSaverProxy Contract that actually performs Repay/Boost
    constructor(address _aaveMonitorProxy, address _subscriptions, address _aaveSaverProxy) public {
        aaveMonitorProxy = AaveMonitorProxy(_aaveMonitorProxy);
        subscriptionsContract = AaveSubscriptions(_subscriptions);
        aaveSaverProxy = _aaveSaverProxy;
    }

    /// @notice Bots call this method to repay for user when conditions are met
    /// @dev If the contract ownes gas token it will try and use it for gas price reduction
    /// @param _exData Exchange data
    /// @param _user The actual address that owns the Aave position
    function repayFor(
        SaverExchangeCore.ExchangeData memory _exData,
        address _user
    ) public payable onlyApproved burnGas(REPAY_GAS_TOKEN) {

        (bool isAllowed, uint ratioBefore) = canCall(Method.Repay, _user);
        require(isAllowed); // check if conditions are met

        uint256 gasCost = calcGasCost(REPAY_GAS_COST);

        aaveMonitorProxy.callExecute{value: msg.value}(
            _user,
            aaveSaverProxy,
            abi.encodeWithSignature(
                "repay((address,address,uint256,uint256,uint256,address,address,bytes,uint256),uint256)",
                _exData,
                gasCost
            )
        );

        (bool isGoodRatio, uint ratioAfter) = ratioGoodAfter(Method.Repay, _user);
        require(isGoodRatio); // check if the after result of the actions is good

        returnEth();

        logger.Log(address(this), _user, "AutomaticAaveRepay", abi.encode(ratioBefore, ratioAfter));
    }

    /// @notice Bots call this method to boost for user when conditions are met
    /// @dev If the contract ownes gas token it will try and use it for gas price reduction
    /// @param _exData Exchange data
    /// @param _user The actual address that owns the Aave position
    function boostFor(
        SaverExchangeCore.ExchangeData memory _exData,
        address _user
    ) public payable onlyApproved burnGas(BOOST_GAS_TOKEN) {

        (bool isAllowed, uint ratioBefore) = canCall(Method.Boost, _user);
        require(isAllowed); // check if conditions are met

        uint256 gasCost = calcGasCost(BOOST_GAS_COST);

        aaveMonitorProxy.callExecute{value: msg.value}(
            _user,
            aaveSaverProxy,
            abi.encodeWithSignature(
                "boost((address,address,uint256,uint256,uint256,address,address,bytes,uint256),uint256)",
                _exData,
                gasCost
            )
        );


        (bool isGoodRatio, uint ratioAfter) = ratioGoodAfter(Method.Boost, _user);
        require(isGoodRatio);  // check if the after result of the actions is good

        returnEth();

        logger.Log(address(this), _user, "AutomaticAaveBoost", abi.encode(ratioBefore, ratioAfter));
    }

/******************* INTERNAL METHODS ********************************/
    function returnEth() internal {
        // return if some eth left
        if (address(this).balance > 0) {
            msg.sender.transfer(address(this).balance);
        }
    }

/******************* STATIC METHODS ********************************/

    /// @notice Checks if Boost/Repay could be triggered for the CDP
    /// @dev Called by AaveMonitor to enforce the min/max check
    /// @param _method Type of action to be called
    /// @param _user The actual address that owns the Aave position
    /// @return Boolean if it can be called and the ratio
    function canCall(Method _method, address _user) public view returns(bool, uint) {
        bool subscribed = subscriptionsContract.isSubscribed(_user);
        AaveSubscriptions.AaveHolder memory holder = subscriptionsContract.getHolder(_user);

        // check if cdp is subscribed
        if (!subscribed) return (false, 0);

        // check if boost and boost allowed
        if (_method == Method.Boost && !holder.boostEnabled) return (false, 0);

        uint currRatio = getSafetyRatio(_user);

        if (_method == Method.Repay) {
            return (currRatio < holder.minRatio, currRatio);
        } else if (_method == Method.Boost) {
            return (currRatio > holder.maxRatio, currRatio);
        }
    }

    /// @dev After the Boost/Repay check if the ratio doesn't trigger another call
    /// @param _method Type of action to be called
    /// @param _user The actual address that owns the Aave position
    /// @return Boolean if the recent action preformed correctly and the ratio
    function ratioGoodAfter(Method _method, address _user) public view returns(bool, uint) {
        AaveSubscriptions.AaveHolder memory holder;

        holder= subscriptionsContract.getHolder(_user);

        uint currRatio = getSafetyRatio(_user);

        if (_method == Method.Repay) {
            return (currRatio < holder.maxRatio, currRatio);
        } else if (_method == Method.Boost) {
            return (currRatio > holder.minRatio, currRatio);
        }
    }

    /// @notice Calculates gas cost (in Eth) of tx
    /// @dev Gas price is limited to MAX_GAS_PRICE to prevent attack of draining user CDP
    /// @param _gasAmount Amount of gas used for the tx
    function calcGasCost(uint _gasAmount) public view returns (uint) {
        uint gasPrice = tx.gasprice <= MAX_GAS_PRICE ? tx.gasprice : MAX_GAS_PRICE;

        return mul(gasPrice, _gasAmount);
    }

/******************* OWNER ONLY OPERATIONS ********************************/

    /// @notice Allows owner to change gas cost for boost operation, but only up to 3 millions
    /// @param _gasCost New gas cost for boost method
    function changeBoostGasCost(uint _gasCost) public onlyOwner {
        require(_gasCost < 3000000);

        BOOST_GAS_COST = _gasCost;
    }

    /// @notice Allows owner to change gas cost for repay operation, but only up to 3 millions
    /// @param _gasCost New gas cost for repay method
    function changeRepayGasCost(uint _gasCost) public onlyOwner {
        require(_gasCost < 3000000);

        REPAY_GAS_COST = _gasCost;
    }

    /// @notice Allows owner to change max gas price
    /// @param _maxGasPrice New max gas price
    function changeMaxGasPrice(uint _maxGasPrice) public onlyOwner {
        require(_maxGasPrice < 500000000000);

        MAX_GAS_PRICE = _maxGasPrice;
    }

    /// @notice Allows owner to change gas token amount
    /// @param _gasTokenAmount New gas token amount
    /// @param _repay true if repay gas token, false if boost gas token
    function changeGasTokenAmount(uint _gasTokenAmount, bool _repay) public onlyOwner {
        if (_repay) {
            REPAY_GAS_TOKEN = _gasTokenAmount;
        } else {
            BOOST_GAS_TOKEN = _gasTokenAmount;
        }
    }
}