Contract 0xf7d924A8F414a16a54F2CF9a98AC266281239FfB

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

import "./Interfaces/IDefaultPool.sol";
import "./Interfaces/IActivePool.sol";
import "./Interfaces/IWhitelist.sol";
import "./Interfaces/IERC20.sol";
import "./Interfaces/IWAsset.sol";
import "./Dependencies/SafeMath.sol";
import "./Dependencies/Ownable.sol";
import "./Dependencies/CheckContract.sol";
import "./Dependencies/YetiCustomBase.sol";


/*
 * The Default Pool holds the collateral and YUSD debt (but not YUSD tokens) from liquidations that have been redistributed
 * to active troves but not yet "applied", i.e. not yet recorded on a recipient active trove's struct.
 *
 * When a trove makes an operation that applies its pending collateral and YUSD debt, its pending collateral and YUSD debt is moved
 * from the Default Pool to the Active Pool.
 */
contract DefaultPool is Ownable, CheckContract, IDefaultPool, YetiCustomBase {
    using SafeMath for uint256;

    string public constant NAME = "DefaultPool";

    address public troveManagerAddress;
    address public activePoolAddress;
    address public whitelistAddress;
    address public yetiFinanceTreasury;

    // deposited collateral tracker. Colls is always the whitelist list of all collateral tokens. Amounts
    newColls internal poolColl;

    uint256 internal YUSDDebt;

    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event DefaultPoolYUSDDebtUpdated(uint256 _YUSDDebt);
    event DefaultPoolBalanceUpdated(address _collateral, uint256 _amount);
    event DefaultPoolBalancesUpdated(address[] _collaterals, uint256[] _amounts);

    // --- Dependency setters ---

    function setAddresses(
        address _troveManagerAddress,
        address _activePoolAddress,
        address _whitelistAddress, 
        address _yetiTreasuryAddress
    ) external onlyOwner {
        checkContract(_troveManagerAddress);
        checkContract(_activePoolAddress);
        checkContract(_whitelistAddress);
        checkContract(_yetiTreasuryAddress);

        troveManagerAddress = _troveManagerAddress;
        activePoolAddress = _activePoolAddress;
        whitelist = IWhitelist(_whitelistAddress);
        whitelistAddress = _whitelistAddress;
        yetiFinanceTreasury = _yetiTreasuryAddress;

        emit TroveManagerAddressChanged(_troveManagerAddress);
        emit ActivePoolAddressChanged(_activePoolAddress);

        _renounceOwnership();
    }

    // --- Internal Functions ---

    // --- Getters for public variables. Required by IPool interface ---

    /*
     * Returns the collateralBalance for a given collateral
     *
     * Returns the amount of a given collateral in state. Not necessarily the contract's actual balance.
     */
    function getCollateral(address _collateral) public view override returns (uint256) {
        return poolColl.amounts[whitelist.getIndex(_collateral)];
    }

    /*
     * Returns all collateral balances in state. Not necessarily the contract's actual balances.
     */
    function getAllCollateral() public view override returns (address[] memory, uint256[] memory) {
        return (poolColl.tokens, poolColl.amounts);
    }

    // returns the VC value of a given collateralAddress in this contract
    function getCollateralVC(address _collateral) external view override returns (uint) {
        return whitelist.getValueVC(_collateral, getCollateral(_collateral));
    }

    /*
     * Returns the VC of the contract
     *
     * Not necessarily equal to the the contract's raw VC balance - Collateral can be forcibly sent to contracts.
     *
     * Computed when called by taking the collateral balances and
     * multiplying them by the corresponding price and ratio and then summing that
     */
    function getVC() external view override returns (uint256 totalVC) {
        uint256 len = poolColl.tokens.length;
        for (uint256 i; i < len; ++i) {
            address collateral = poolColl.tokens[i];
            uint256 amount = poolColl.amounts[i];

            uint256 collateralVC = whitelist.getValueVC(collateral, amount);
            totalVC = totalVC.add(collateralVC);
        }
        return totalVC;
    }

    // Debt that this pool holds. 
    function getYUSDDebt() external view override returns (uint256) {
        return YUSDDebt;
    }

    // Internal function to send collateral to a different pool. 
    function _sendCollateral(address _collateral, uint256 _amount) internal {
        address activePool = activePoolAddress;
        uint256 index = whitelist.getIndex(_collateral);
        poolColl.amounts[index] = poolColl.amounts[index].sub(_amount);

        emit DefaultPoolBalanceUpdated(_collateral, _amount);
        emit CollateralSent(_collateral, activePool, _amount);

        bool success = IERC20(_collateral).transfer(activePool, _amount);
        require(success, "DefaultPool: sending collateral failed");
    }

    // Returns true if all payments were successfully sent. Must be called by borrower operations, trove manager, or stability pool. 
    function sendCollsToActivePool(address[] memory _tokens, uint256[] memory _amounts, address _borrower)
        external
        override
    {
        _requireCallerIsTroveManager();
        address activePool = activePoolAddress;
        uint256 tokensLen = _tokens.length;
        require(tokensLen == _amounts.length);
        for (uint256 i; i < tokensLen; ++i) {
            uint256 thisAmounts = _amounts[i];
            if(thisAmounts != 0) {
                address thisToken = _tokens[i];
                _sendCollateral(thisToken, _amounts[i]);
                if (whitelist.isWrapped(thisToken)) {
                    IWAsset(thisToken).updateReward(yetiFinanceTreasury, _borrower, _amounts[i]);
                }
            }
        }
        IActivePool(activePool).receiveCollateral(_tokens, _amounts);
    }

    // Increases the YUSD Debt of this pool. 
    function increaseYUSDDebt(uint256 _amount) external override {
        _requireCallerIsTroveManager();
        YUSDDebt = YUSDDebt.add(_amount);
        emit DefaultPoolYUSDDebtUpdated(YUSDDebt);
    }

    // Decreases the YUSD Debt of this pool.
    function decreaseYUSDDebt(uint256 _amount) external override {
        _requireCallerIsTroveManager();
        YUSDDebt = YUSDDebt.sub(_amount);
        emit DefaultPoolYUSDDebtUpdated(YUSDDebt);
    }

    // --- 'require' functions ---

    function _requireCallerIsActivePool() internal view {
        require(msg.sender == activePoolAddress, "DefaultPool: Caller is not the ActivePool");
    }

    function _requireCallerIsTroveManager() internal view {
        require(msg.sender == troveManagerAddress, "DefaultPool: Caller is not the TroveManager");
    }

    function _requireCallerIsWhitelist() internal view {
        require(msg.sender == address(whitelist), "DefaultPool: Caller is not whitelist");
    }

    // Should be called by ActivePool
    // __after__ collateral is transferred to this contract from Active Pool
    function receiveCollateral(address[] memory _tokens, uint256[] memory _amounts)
        external
        override
    {
        _requireCallerIsActivePool();
        poolColl.amounts = _leftSumColls(poolColl, _tokens, _amounts);
        emit DefaultPoolBalancesUpdated(_tokens, _amounts);
    }

    // Adds collateral type from whitelist. 
    function addCollateralType(address _collateral) external override {
        _requireCallerIsWhitelist();
        poolColl.tokens.push(_collateral);
        poolColl.amounts.push(0);
    }
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

import "./IPool.sol";

interface IDefaultPool is IPool {
    // --- Events ---
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event DefaultPoolYUSDDebtUpdated(uint _YUSDDebt);
    event DefaultPoolETHBalanceUpdated(uint _ETH);

    // --- Functions ---
    
    function sendCollsToActivePool(address[] memory _collaterals, uint[] memory _amounts, address _borrower) external;
    function addCollateralType(address _collateral) external;
    function getCollateralVC(address collateralAddress) external view returns (uint);
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

import "./IPool.sol";

    
interface IActivePool is IPool {
    // --- Events ---
    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event ActivePoolYUSDDebtUpdated(uint _YUSDDebt);
    event ActivePoolCollateralBalanceUpdated(address _collateral, uint _amount);

    // --- Functions ---
    
    function sendCollaterals(address _to, address[] memory _tokens, uint[] memory _amounts) external returns (bool);
    function sendCollateralsUnwrap(
        address _to,
        address[] memory _tokens,
        uint[] memory _amounts,
        bool _collectRewards) external returns (bool);
    function getCollateralVC(address collateralAddress) external view returns (uint);
    function addCollateralType(address _collateral) external;
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;


interface IWhitelist {
    function getValidCollateral() view external returns (address[] memory);

    function setAddresses(
        address _activePoolAddress,
        address _defaultPoolAddress,
        address _stabilityPoolAddress,
        address _collSurplusPoolAddress, 
        address _borrowerOperationsAddress
    ) external;

    function isValidRouter(address _router) external view returns (bool);
    function getOracle(address _collateral) view external returns (address);
    function getRatio(address _collateral) view external returns (uint256);
    function getIsActive(address _collateral) view external returns (bool);
    function getPriceCurve(address _collateral) external view returns (address);
    function getDecimals(address _collateral) external view returns (uint256);
    function getFee(address _collateral, uint _collateralVCInput, uint256 _collateralVCBalancePost, uint256 _totalVCBalancePre, uint256 _totalVCBalancePost) external view returns (uint256 fee);
    function getFeeAndUpdate(address _collateral, uint _collateralVCInput, uint256 _collateralVCBalancePost, uint256 _totalVCBalancePre, uint256 _totalVCBalancePost) external returns (uint256 fee);
    function getIndex(address _collateral) external view returns (uint256);
    function isWrapped(address _collateral) external view returns (bool);
    function setDefaultRouter(address _collateral, address _router) external;

    function getValueVC(address _collateral, uint _amount) view external returns (uint);
    function getValueUSD(address _collateral, uint _amount) view external returns (uint256);
    function getDefaultRouterAddress(address _collateral) external view returns (address);
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

/**
 * Based on the OpenZeppelin IER20 interface:
 * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol
 *
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;


// Wrapped Asset
interface IWAsset  {

    function wrap(uint _amount, address _from, address _to, address _rewardOwner) external;

    function unwrapFor(address _for, uint amount) external;

    function updateReward(address from, address to, uint amount) external;

    function claimReward(address _to) external;

    function claimRewardFor(address _for) external;

    function getPendingRewards(address _for) external returns (address[] memory tokens, uint[] memory amounts);

    function endTreasuryReward(uint _amount) external;
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

/**
 * Based on OpenZeppelin's SafeMath:
 * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/SafeMath.sol
 *
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    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;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        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;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

/**
 * Based on OpenZeppelin's Ownable contract:
 * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol
 *
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), msg.sender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     *
     * NOTE: This function is not safe, as it doesn’t check owner is calling it.
     * Make sure you check it before calling it.
     */
    function _renounceOwnership() internal {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;


contract CheckContract {
    /**
     * Check that the account is an already deployed non-destroyed contract.
     * See: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol#L12
     */
    function checkContract(address _account) internal view {
        require(_account != address(0), "Account cannot be zero address");

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(_account) }
        require(size > 0, "Account code size cannot be zero");
    }
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

import "./BaseMath.sol";
import "./SafeMath.sol";
import "../Interfaces/IERC20.sol";
import "../Interfaces/IWhitelist.sol";


contract YetiCustomBase is BaseMath {
    using SafeMath for uint256;

    IWhitelist whitelist;

    struct newColls {
        // tokens and amounts should be the same length
        address[] tokens;
        uint256[] amounts;
    }

    // Collateral math

    // gets the sum of _coll1 and _coll2
    function _sumColls(newColls memory _coll1, newColls memory _coll2)
        internal
        view
        returns (newColls memory finalColls)
    {
        newColls memory coll3;

        coll3.tokens = whitelist.getValidCollateral();
        coll3.amounts = new uint256[](coll3.tokens.length);

        uint256 n = 0;
        for (uint256 i = 0; i < _coll1.tokens.length; i++) {
            uint256 tokenIndex = whitelist.getIndex(_coll1.tokens[i]);
            if (_coll1.amounts[i] > 0) {
                n++;
                coll3.amounts[tokenIndex] = _coll1.amounts[i];
            }
        }

        for (uint256 i = 0; i < _coll2.tokens.length; i++) {
            uint256 tokenIndex = whitelist.getIndex(_coll2.tokens[i]);
            if (_coll2.amounts[i] > 0) {
                if (coll3.amounts[tokenIndex] == 0) {
                    n++;
                }
                coll3.amounts[tokenIndex] = coll3.amounts[tokenIndex].add(_coll2.amounts[i]);
            }
        }

        address[] memory sumTokens = new address[](n);
        uint256[] memory sumAmounts = new uint256[](n);
        uint256 j = 0;

        // should only find n amounts over 0
        for (uint256 i = 0; i < coll3.tokens.length; i++) {
            if (coll3.amounts[i] > 0) {
                sumTokens[j] = coll3.tokens[i];
                sumAmounts[j] = coll3.amounts[i];
                j++;
            }
        }
        finalColls.tokens = sumTokens;
        finalColls.amounts = sumAmounts;
    }


    // gets the sum of coll1 with tokens and amounts
    function _sumColls(
        newColls memory _coll1,
        address[] memory tokens,
        uint256[] memory amounts
    ) internal view returns (newColls memory) {
        newColls memory coll2 = newColls(tokens, amounts);
        return _sumColls(_coll1, coll2);
    }


    function _sumColls(
        address[] memory tokens1,
        uint256[] memory amounts1,
        address[] memory tokens2,
        uint256[] memory amounts2
    ) internal view returns (newColls memory) {
        newColls memory coll1 = newColls(tokens1, amounts1);
        return _sumColls(coll1, tokens2, amounts2);
    }


    // Function for summing colls when coll1 includes all the tokens in the whitelist
    // Used in active, default, stability, and surplus pools
    // assumes _coll1.tokens = all whitelisted tokens
    function _leftSumColls(
        newColls memory _coll1,
        address[] memory _tokens,
        uint256[] memory _amounts
    ) internal view returns (uint[] memory) {
        uint[] memory sumAmounts = _getArrayCopy(_coll1.amounts);

        // assumes that sumAmounts length = whitelist tokens length.
        for (uint256 i = 0; i < _tokens.length; i++) {
            uint tokenIndex = whitelist.getIndex(_tokens[i]);
            sumAmounts[tokenIndex] = sumAmounts[tokenIndex].add(_amounts[i]);
        }

        return sumAmounts;
    }


    // Function for summing colls when one list is all tokens. Used in active, default, stability, and surplus pools
    function _leftSubColls(newColls memory _coll1, address[] memory _subTokens, uint[] memory _subAmounts)
        internal
        view
        returns (uint[] memory)
    {
        uint[] memory diffAmounts = _getArrayCopy(_coll1.amounts);

        //assumes that coll1.tokens = whitelist tokens. Keeps all of coll1's tokens, and subtracts coll2's amounts
        for (uint256 i = 0; i < _subTokens.length; i++) {
            uint256 tokenIndex = whitelist.getIndex(_subTokens[i]);
            diffAmounts[tokenIndex] = diffAmounts[tokenIndex].sub(_subAmounts[i]);
        }
        return diffAmounts;
    }
    

    // Returns _coll1 minus _tokens and _amounts
    // will error if _tokens include a token not in _coll1.tokens
    function _subColls(newColls memory _coll1, address[] memory _tokens, uint[] memory _amounts)
        internal
        view
        returns (newColls memory finalColls)
    {
        require(_tokens.length == _amounts.length, "Sub Colls invalid input");

        newColls memory coll3;
        coll3.tokens = whitelist.getValidCollateral();
        coll3.amounts = new uint256[](coll3.tokens.length);
        uint256 n = 0;

        for (uint256 i = 0; i < _coll1.tokens.length; i++) {
            if (_coll1.amounts[i] > 0) {
                uint256 tokenIndex = whitelist.getIndex(_coll1.tokens[i]);
                coll3.amounts[tokenIndex] = _coll1.amounts[i];
                n++;
            }
        }

        for (uint256 i = 0; i < _tokens.length; i++) {
            uint256 tokenIndex = whitelist.getIndex(_tokens[i]);
            require(coll3.amounts[tokenIndex] >= _amounts[i], "illegal sub");
            coll3.amounts[tokenIndex] = coll3.amounts[tokenIndex].sub(_amounts[i]);
            if (coll3.amounts[tokenIndex] == 0) {
                n--;
            }
        }

        address[] memory diffTokens = new address[](n);
        uint256[] memory diffAmounts = new uint256[](n);
        uint256 j = 0;

        for (uint256 i = 0; i < coll3.tokens.length; i++) {
            if (coll3.amounts[i] > 0) {
                diffTokens[j] = coll3.tokens[i];
                diffAmounts[j] = coll3.amounts[i];
                j++;
            }
        }
        finalColls.tokens = diffTokens;
        finalColls.amounts = diffAmounts;
    }

    function _getArrayCopy(uint[] memory _arr) internal pure returns (uint[] memory){
        uint[] memory copy = new uint[](_arr.length);
        for (uint i = 0; i < _arr.length; i++) {
            copy[i] = _arr[i];
        }
        return copy;
    }
}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

import "./ICollateralReceiver.sol";

// Common interface for the Pools.
interface IPool is ICollateralReceiver {
    
    // --- Events ---
    
    event ETHBalanceUpdated(uint _newBalance);
    event YUSDBalanceUpdated(uint _newBalance);
    event ActivePoolAddressChanged(address _newActivePoolAddress);
    event DefaultPoolAddressChanged(address _newDefaultPoolAddress);
    event StabilityPoolAddressChanged(address _newStabilityPoolAddress);
    event WhitelistAddressChanged(address _newWhitelistAddress);
    event EtherSent(address _to, uint _amount);
    event CollateralSent(address _collateral, address _to, uint _amount);

    // --- Functions ---

    function getVC() external view returns (uint);

    function getCollateral(address collateralAddress) external view returns (uint);

    function getAllCollateral() external view returns (address[] memory, uint256[] memory);

    function getYUSDDebt() external view returns (uint);

    function increaseYUSDDebt(uint _amount) external;

    function decreaseYUSDDebt(uint _amount) external;

}

// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.11;

interface ICollateralReceiver {
    function receiveCollateral(address[] memory _tokens, uint[] memory _amounts) external;
}

// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;


contract BaseMath {
    uint constant public DECIMAL_PRECISION = 1e18;
}

{
  "optimizer": {
    "enabled": true,
    "runs": 100
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  },
  "libraries": {}
}

[{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_newActivePoolAddress","type":"address"}],"name":"ActivePoolAddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_collateral","type":"address"},{"indexed":false,"internalType":"address","name":"_to","type":"address"},{"indexed":false,"internalType":"uint256","name":"_amount","type":"uint256"}],"name":"CollateralSent","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_newDefaultPoolAddress","type":"address"}],"name":"DefaultPoolAddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_collateral","type":"address"},{"indexed":false,"internalType":"uint256","name":"_amount","type":"uint256"}],"name":"DefaultPoolBalanceUpdated","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address[]","name":"_collaterals","type":"address[]"},{"indexed":false,"internalType":"uint256[]","name":"_amounts","type":"uint256[]"}],"name":"DefaultPoolBalancesUpdated","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"_ETH","type":"uint256"}],"name":"DefaultPoolETHBalanceUpdated","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"_YUSDDebt","type":"uint256"}],"name":"DefaultPoolYUSDDebtUpdated","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"_newBalance","type":"uint256"}],"name":"ETHBalanceUpdated","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_to","type":"address"},{"indexed":false,"internalType":"uint256","name":"_amount","type":"uint256"}],"name":"EtherSent","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"previousOwner","type":"address"},{"indexed":true,"internalType":"address","name":"newOwner","type":"address"}],"name":"OwnershipTransferred","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_newStabilityPoolAddress","type":"address"}],"name":"StabilityPoolAddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_newTroveManagerAddress","type":"address"}],"name":"TroveManagerAddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_newWhitelistAddress","type":"address"}],"name":"WhitelistAddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"_newBalance","type":"uint256"}],"name":"YUSDBalanceUpdated","type":"event"},{"inputs":[],"name":"DECIMAL_PRECISION","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"NAME","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"activePoolAddress","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"_collateral","type":"address"}],"name":"addCollateralType","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"_amount","type":"uint256"}],"name":"decreaseYUSDDebt","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"getAllCollateral","outputs":[{"internalType":"address[]","name":"","type":"address[]"},{"internalType":"uint256[]","name":"","type":"uint256[]"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"_collateral","type":"address"}],"name":"getCollateral","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"_collateral","type":"address"}],"name":"getCollateralVC","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getVC","outputs":[{"internalType":"uint256","name":"totalVC","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"getYUSDDebt","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"_amount","type":"uint256"}],"name":"increaseYUSDDebt","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"isOwner","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"owner","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address[]","name":"_tokens","type":"address[]"},{"internalType":"uint256[]","name":"_amounts","type":"uint256[]"}],"name":"receiveCollateral","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address[]","name":"_tokens","type":"address[]"},{"internalType":"uint256[]","name":"_amounts","type":"uint256[]"},{"internalType":"address","name":"_borrower","type":"address"}],"name":"sendCollsToActivePool","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"_troveManagerAddress","type":"address"},{"internalType":"address","name":"_activePoolAddress","type":"address"},{"internalType":"address","name":"_whitelistAddress","type":"address"},{"internalType":"address","name":"_yetiTreasuryAddress","type":"address"}],"name":"setAddresses","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"troveManagerAddress","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"whitelistAddress","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"yetiFinanceTreasury","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"}]

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