// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



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

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

// File: contracts/Dependencies/BaseMath.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;


contract BaseMath {
    uint256 constant public DECIMAL_PRECISION = 1e18;
}

// File: contracts/Dependencies/CheckContract.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;


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");
    }
}

// File: contracts/Dependencies/IERC2612.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

/**
 * @dev Interface of the ERC2612 standard as defined in the EIP.
 *
 * Adds the {permit} method, which can be used to change one's
 * {IERC20-allowance} without having to send a transaction, by signing a
 * message. This allows users to spend tokens without having to hold Ether.
 *
 * See https://eips.ethereum.org/EIPS/eip-2612.
 * 
 * Code adapted from https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237/
 */
interface IERC2612 {
    /**
     * @dev Sets `amount` as the allowance of `spender` over `owner`'s tokens,
     * given `owner`'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(address owner, address spender, uint256 amount, 
                    uint256 deadline, uint8 v, bytes32 r, bytes32 s) external;
    
    /**
     * @dev Returns the current ERC2612 nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases `owner`'s nonce by one. This
     * prevents a signature from being used multiple times.
     *
     * `owner` can limit the time a Permit is valid for by setting `deadline` to 
     * a value in the near future. The deadline argument can be set to uint(-1) to 
     * create Permits that effectively never expire.
     */
    function nonces(address owner) external view returns (uint256);
    
    function version() external view returns (string memory);
    function permitTypeHash() external view returns (bytes32);
    function domainSeparator() external view returns (bytes32);
}

// File: contracts/Dependencies/LiquityBase.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "./BaseMath.sol";
import "./LiquityMath.sol";
import "../Interfaces/IActivePool.sol";
import "../Interfaces/IDefaultPool.sol";
import "../Interfaces/IPriceFeed.sol";
import "../Interfaces/ILiquityBase.sol";

/*
* Base contract for TroveManager, BorrowerOperations and StabilityPool. Contains global system constants and
* common functions.
*/
contract LiquityBase is BaseMath, ILiquityBase {

    uint256 constant public _100pct = 1e18; // 1e18 == 100%

    // Minimum collateral ratio for individual troves
    uint256 constant public MCR = 1.1e18; // 110%

    // Critical system collateral ratio. If the system's total collateral ratio (TCR) falls below the CCR, Recovery Mode is triggered.
    uint256 constant public CCR = 1.5e18; // 150%

    // Amount of THUSD to be locked in gas pool on opening troves
    uint256 constant public THUSD_GAS_COMPENSATION = 200e18;

    // Minimum amount of net THUSD debt a trove must have
    uint256 constant public MIN_NET_DEBT = 1800e18;
    // uint256 constant public MIN_NET_DEBT = 0;

    uint256 constant public PERCENT_DIVISOR = 200; // dividing by 200 yields 0.5%

    uint256 constant public BORROWING_FEE_FLOOR = DECIMAL_PRECISION / 1000 * 5; // 0.5%

    IActivePool public activePool;

    IDefaultPool public defaultPool;

    IPriceFeed public override priceFeed;

    // --- Gas compensation functions ---

    // Returns the composite debt (drawn debt + gas compensation) of a trove, for the purpose of ICR calculation
    function _getCompositeDebt(uint256 _debt) internal pure returns (uint) {
        return _debt + THUSD_GAS_COMPENSATION;
    }

    function _getNetDebt(uint256 _debt) internal pure returns (uint) {
        return _debt - THUSD_GAS_COMPENSATION;
    }

    // Return the amount of collateral to be drawn from a trove's collateral and sent as gas compensation.
    function _getCollGasCompensation(uint256 _entireColl) internal pure returns (uint) {
        return _entireColl / PERCENT_DIVISOR;
    }

    function getEntireSystemColl() public view returns (uint256 entireSystemColl) {
        uint256 activeColl = activePool.getCollateralBalance();
        uint256 liquidatedColl = defaultPool.getCollateralBalance();

        return activeColl + liquidatedColl;
    }

    function getEntireSystemDebt() public view returns (uint256 entireSystemDebt) {
        uint256 activeDebt = activePool.getTHUSDDebt();
        uint256 closedDebt = defaultPool.getTHUSDDebt();

        return activeDebt + closedDebt;
    }

    function _getTCR(uint256 _price) internal view returns (uint256 TCR) {
        uint256 entireSystemColl = getEntireSystemColl();
        uint256 entireSystemDebt = getEntireSystemDebt();

        TCR = LiquityMath._computeCR(entireSystemColl, entireSystemDebt, _price);
        return TCR;
    }

    function _checkRecoveryMode(uint256 _price) internal view returns (bool) {
        uint256 TCR = _getTCR(_price);
        return TCR < CCR;
    }

    function _requireUserAcceptsFee(uint256 _fee, uint256 _amount, uint256 _maxFeePercentage) internal pure {
        uint256 feePercentage = _fee * DECIMAL_PRECISION / _amount;
        require(feePercentage <= _maxFeePercentage, "Fee exceeded provided maximum");
    }
}

// File: contracts/Dependencies/LiquityMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

library LiquityMath {

    uint256 internal constant DECIMAL_PRECISION = 1e18;

    /* Precision for Nominal ICR (independent of price). Rationale for the value:
     *
     * - Making it “too high” could lead to overflows.
     * - Making it “too low” could lead to an ICR equal to zero, due to truncation from Solidity floor division.
     *
     * This value of 1e20 is chosen for safety: the NICR will only overflow for numerator > ~1e39 ETH,
     * and will only truncate to 0 if the denominator is at least 1e20 times greater than the numerator.
     *
     */
    uint256 internal constant NICR_PRECISION = 1e20;

    function _min(uint256 _a, uint256 _b) internal pure returns (uint) {
        return (_a < _b) ? _a : _b;
    }

    function _max(uint256 _a, uint256 _b) internal pure returns (uint) {
        return (_a >= _b) ? _a : _b;
    }

    /*
    * Multiply two decimal numbers and use normal rounding rules:
    * -round product up if 19'th mantissa digit >= 5
    * -round product down if 19'th mantissa digit < 5
    *
    * Used only inside the exponentiation, _decPow().
    */
    function decMul(uint256 x, uint256 y) internal pure returns (uint256 decProd) {
        uint256 prod_xy = x * y;

        decProd = (prod_xy + (DECIMAL_PRECISION / 2)) / DECIMAL_PRECISION;
    }

    /*
    * _decPow: Exponentiation function for 18-digit decimal base, and integer exponent n.
    *
    * Uses the efficient "exponentiation by squaring" algorithm. O(log(n)) complexity.
    *
    * Called by one function that represent time in units of minutes:
    * 1) TroveManager._calcDecayedBaseRate
    *
    * The exponent is capped to avoid reverting due to overflow. The cap 525600000 equals
    * "minutes in 1000 years": 60 * 24 * 365 * 1000
    *
    * If a period of > 1000 years is ever used as an exponent in either of the above functions, the result will be
    * negligibly different from just passing the cap, since:
    *
    * In function 1), the decayed base rate will be 0 for 1000 years or > 1000 years
    * In function 2), the difference in tokens issued at 1000 years and any time > 1000 years, will be negligible
    */
    function _decPow(uint256 _base, uint256 _minutes) internal pure returns (uint) {

        if (_minutes > 525600000) {_minutes = 525600000;}  // cap to avoid overflow

        if (_minutes == 0) {return DECIMAL_PRECISION;}

        uint256 y = DECIMAL_PRECISION;
        uint256 x = _base;
        uint256 n = _minutes;

        // Exponentiation-by-squaring
        while (n > 1) {
            if (n % 2 == 0) {
                x = decMul(x, x);
                n = n / 2;
            } else { // if (n % 2 != 0)
                y = decMul(x, y);
                x = decMul(x, x);
                n = (n - 1) / 2;
            }
        }

        return decMul(x, y);
  }

    function _getAbsoluteDifference(uint256 _a, uint256 _b) internal pure returns (uint) {
        return (_a >= _b) ? _a - _b : _b - _a;
    }

    function _computeNominalCR(uint256 _coll, uint256 _debt) internal pure returns (uint) {
        if (_debt > 0) {
            return _coll * NICR_PRECISION / _debt;
        }
        // Return the maximal value for uint256 if the Trove has a debt of 0. Represents "infinite" CR.
        else { // if (_debt == 0)
            return type(uint256).max;
        }
    }

    function _computeCR(uint256 _coll, uint256 _debt, uint256 _price) internal pure returns (uint) {
        if (_debt > 0) {
            uint256 newCollRatio = _coll * _price / _debt;

            return newCollRatio;
        }
        // Return the maximal value for uint256 if the Trove has a debt of 0. Represents "infinite" CR.
        else { // if (_debt == 0)
            return type(uint256).max;
        }
    }
}

// File: contracts/Dependencies/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

/**
 * 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 () {
        _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);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: contracts/HintHelpers.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "./Interfaces/ITroveManager.sol";
import "./Interfaces/ISortedTroves.sol";
import "./Dependencies/LiquityBase.sol";
import "./Dependencies/Ownable.sol";
import "./Dependencies/CheckContract.sol";

contract HintHelpers is LiquityBase, Ownable, CheckContract {

    string constant public NAME = "HintHelpers";

    ISortedTroves public sortedTroves;
    ITroveManager public troveManager;

    // --- Events ---

    event SortedTrovesAddressChanged(address _sortedTrovesAddress);
    event TroveManagerAddressChanged(address _troveManagerAddress);

    // --- Dependency setters ---

    function setAddresses(
        address _sortedTrovesAddress,
        address _troveManagerAddress
    )
        external
        onlyOwner
    {
        checkContract(_sortedTrovesAddress);
        checkContract(_troveManagerAddress);

        sortedTroves = ISortedTroves(_sortedTrovesAddress);
        troveManager = ITroveManager(_troveManagerAddress);

        emit SortedTrovesAddressChanged(_sortedTrovesAddress);
        emit TroveManagerAddressChanged(_troveManagerAddress);

        _renounceOwnership();
    }

    // --- Functions ---

    /* getRedemptionHints() - Helper function for finding the right hints to pass to redeemCollateral().
     *
     * It simulates a redemption of `_THUSDamount` to figure out where the redemption sequence will start and what state the final Trove
     * of the sequence will end up in.
     *
     * Returns three hints:
     *  - `firstRedemptionHint` is the address of the first Trove with ICR >= MCR (i.e. the first Trove that will be redeemed).
     *  - `partialRedemptionHintNICR` is the final nominal ICR of the last Trove of the sequence after being hit by partial redemption,
     *     or zero in case of no partial redemption.
     *  - `truncatedTHUSDamount` is the maximum amount that can be redeemed out of the the provided `_THUSDamount`. This can be lower than
     *    `_THUSDamount` when redeeming the full amount would leave the last Trove of the redemption sequence with less net debt than the
     *    minimum allowed value (i.e. MIN_NET_DEBT).
     *
     * The number of Troves to consider for redemption can be capped by passing a non-zero value as `_maxIterations`, while passing zero
     * will leave it uncapped.
     */

    function getRedemptionHints(
        uint256 _THUSDamount,
        uint256 _price,
        uint256 _maxIterations
    )
        external
        view
        returns (
            address firstRedemptionHint,
            uint256 partialRedemptionHintNICR,
            uint256 truncatedTHUSDamount
        )
    {
        ISortedTroves sortedTrovesCached = sortedTroves;

        uint256 remainingTHUSD = _THUSDamount;
        address currentTroveuser = sortedTrovesCached.getLast();

        while (currentTroveuser != address(0) && troveManager.getCurrentICR(currentTroveuser, _price) < MCR) {
            currentTroveuser = sortedTrovesCached.getPrev(currentTroveuser);
        }

        firstRedemptionHint = currentTroveuser;

        if (_maxIterations == 0) {
            _maxIterations = type(uint256).max;
        }

        while (currentTroveuser != address(0) && remainingTHUSD > 0 && _maxIterations-- > 0) {
            uint256 netTHUSDDebt = _getNetDebt(troveManager.getTroveDebt(currentTroveuser))
                + troveManager.getPendingTHUSDDebtReward(currentTroveuser);

            if (netTHUSDDebt > remainingTHUSD) {
                if (netTHUSDDebt > MIN_NET_DEBT) {
                    uint256 maxRedeemableTHUSD = LiquityMath._min(remainingTHUSD, netTHUSDDebt - MIN_NET_DEBT);

                    uint256 collateral = troveManager.getTroveColl(currentTroveuser)
                        + troveManager.getPendingCollateralReward(currentTroveuser);

                    uint256 newColl = collateral - (maxRedeemableTHUSD * DECIMAL_PRECISION / _price);
                    uint256 newDebt = netTHUSDDebt - maxRedeemableTHUSD;

                    uint256 compositeDebt = _getCompositeDebt(newDebt);
                    partialRedemptionHintNICR = LiquityMath._computeNominalCR(newColl, compositeDebt);

                    remainingTHUSD -= maxRedeemableTHUSD;
                }
                break;
            } else {
                remainingTHUSD -= netTHUSDDebt;
            }

            currentTroveuser = sortedTrovesCached.getPrev(currentTroveuser);
        }

        truncatedTHUSDamount = _THUSDamount - remainingTHUSD;
    }

    /* getApproxHint() - return address of a Trove that is, on average, (length / numTrials) positions away in the
    sortedTroves list from the correct insert position of the Trove to be inserted.

    Note: The output address is worst-case O(n) positions away from the correct insert position, however, the function
    is probabilistic. Input can be tuned to guarantee results to a high degree of confidence, e.g:

    Submitting numTrials = k * sqrt(length), with k = 15 makes it very, very likely that the ouput address will
    be <= sqrt(length) positions away from the correct insert position.
    */
    function getApproxHint(uint256 _CR, uint256 _numTrials, uint256 _inputRandomSeed)
        external
        view
        returns (address hintAddress, uint256 diff, uint256 latestRandomSeed)
    {
        uint256 arrayLength = troveManager.getTroveOwnersCount();

        if (arrayLength == 0) {
            return (address(0), 0, _inputRandomSeed);
        }

        hintAddress = sortedTroves.getLast();
        diff = LiquityMath._getAbsoluteDifference(_CR, troveManager.getNominalICR(hintAddress));
        latestRandomSeed = _inputRandomSeed;

        uint256 i = 1;

        while (i < _numTrials) {
            latestRandomSeed = uint(keccak256(abi.encodePacked(latestRandomSeed)));

            uint256 arrayIndex = latestRandomSeed % arrayLength;
            address currentAddress = troveManager.getTroveFromTroveOwnersArray(arrayIndex);
            uint256 currentNICR = troveManager.getNominalICR(currentAddress);

            // check if abs(current - CR) > abs(closest - CR), and update closest if current is closer
            uint256 currentDiff = LiquityMath._getAbsoluteDifference(currentNICR, _CR);

            if (currentDiff < diff) {
                diff = currentDiff;
                hintAddress = currentAddress;
            }
            i++;
        }
    }

    function computeNominalCR(uint256 _coll, uint256 _debt) external pure returns (uint) {
        return LiquityMath._computeNominalCR(_coll, _debt);
    }

    function computeCR(uint256 _coll, uint256 _debt, uint256 _price) external pure returns (uint) {
        return LiquityMath._computeCR(_coll, _debt, _price);
    }
}

// File: contracts/Interfaces/IActivePool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "./IPool.sol";


interface IActivePool is IPool {
    // --- Events ---
    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event ActivePoolTHUSDDebtUpdated(uint256 _THUSDDebt);
    event ActivePoolCollateralBalanceUpdated(uint256 _collateral);
    event CollateralAddressChanged(address _newCollateralAddress);
    event CollSurplusPoolAddressChanged(address _newCollSurplusPoolAddress);

    // --- Functions ---
    function sendCollateral(address _account, uint256 _amount) external;
    function updateCollateralBalance(uint256 _amount) external;
    function collateralAddress() external view returns(address);
}

// File: contracts/Interfaces/IDefaultPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "./IPool.sol";


interface IDefaultPool is IPool {
    // --- Events ---
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event DefaultPoolTHUSDDebtUpdated(uint256 _THUSDDebt);
    event DefaultPoolCollateralBalanceUpdated(uint256 _collateral);
    event CollateralAddressChanged(address _newCollateralAddress);

    // --- Functions ---
    function sendCollateralToActivePool(uint256 _amount) external;
    function updateCollateralBalance(uint256 _amount) external;
    function collateralAddress() external view returns(address);
}

// File: contracts/Interfaces/ILiquityBase.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "./IPriceFeed.sol";


interface ILiquityBase {
    function priceFeed() external view returns (IPriceFeed);
}

// File: contracts/Interfaces/IPCV.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./ITHUSDToken.sol";

interface IPCV {

    // --- Events --
    event THUSDTokenAddressSet(address _thusdTokenAddress);
    event BorrowerOperationsAddressSet(address _borrowerOperationsAddress);
    event CollateralAddressSet(address _collateralAddress);
    event BAMMAddressSet(address _bammAddress);
    event RolesSet(address _council, address _treasury);

    event BAMMDeposit(uint256 _thusdAmount);
    event BAMMWithdraw(uint256 _numShares);
    event THUSDWithdraw(address _recipient, uint256 _thusdAmount);
    event CollateralWithdraw(address _recipient, uint256 _collateralAmount);

    event PCVDebtPaid(uint256 _paidDebt);
    
    event RecipientAdded(address _recipient);
    event RecipientRemoved(address _recipient);

    // --- Functions ---

    function debtToPay() external returns(uint256);
    function payDebt(uint256 _thusdToBurn) external;

    function setAddresses(
        address _thusdTokenAddress, 
        address _borrowerOperations, 
        address payable _bammAddress,
        address _collateralERC20
    ) external;
    function initialize() external;

    function depositToBAMM(uint256 _thusdAmount) external;
    function withdrawFromBAMM(uint256 _numShares) external;
    function withdrawTHUSD(address _recipient, uint256 _thusdAmount) external;
    function withdrawCollateral(address _recipient, uint256 _collateralAmount) external;

    function addRecipientToWhitelist(address _recipient) external;
    function addRecipientsToWhitelist(address[] calldata _recipients) external;
    function removeRecipientFromWhitelist(address _recipient) external;
    function removeRecipientsFromWhitelist(address[] calldata _recipients) external;

    function startChangingRoles(address _council, address _treasury) external;
    function cancelChangingRoles() external;
    function finalizeChangingRoles() external;
    
    function collateralERC20() external view returns(IERC20);
    function thusdToken() external view returns(ITHUSDToken);

}

// File: contracts/Interfaces/IPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

// Common interface for the Pools.
interface IPool {

    // --- Events ---

    event CollateralBalanceUpdated(uint256 _newBalance);
    event THUSDBalanceUpdated(uint256 _newBalance);
    event ActivePoolAddressChanged(address _newActivePoolAddress);
    event DefaultPoolAddressChanged(address _newDefaultPoolAddress);
    event StabilityPoolAddressChanged(address _newStabilityPoolAddress);
    event CollateralSent(address _to, uint256 _amount);

    // --- Functions ---

    function getCollateralBalance() external view returns (uint);

    function getTHUSDDebt() external view returns (uint);

    function increaseTHUSDDebt(uint256 _amount) external;

    function decreaseTHUSDDebt(uint256 _amount) external;
}

// File: contracts/Interfaces/IPriceFeed.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

interface IPriceFeed {

    // --- Events ---
    event LastGoodPriceUpdated(uint256 _lastGoodPrice);
   
    // --- Function ---
    function fetchPrice() external returns (uint);
}

// File: contracts/Interfaces/ISortedTroves.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

// Common interface for the SortedTroves Doubly Linked List.
interface ISortedTroves {

    // --- Events ---
    
    event SortedTrovesAddressChanged(address _sortedDoublyLLAddress);
    event BorrowerOperationsAddressChanged(address _borrowerOperationsAddress);
    event NodeAdded(address _id, uint256 _NICR);
    event NodeRemoved(address _id);

    // --- Functions ---
    
    function setParams(uint256 _size, address _TroveManagerAddress, address _borrowerOperationsAddress) external;

    function insert(address _id, uint256 _ICR, address _prevId, address _nextId) external;

    function remove(address _id) external;

    function reInsert(address _id, uint256 _newICR, address _prevId, address _nextId) external;

    function contains(address _id) external view returns (bool);

    function isFull() external view returns (bool);

    function isEmpty() external view returns (bool);

    function getSize() external view returns (uint256);

    function getMaxSize() external view returns (uint256);

    function getFirst() external view returns (address);

    function getLast() external view returns (address);

    function getNext(address _id) external view returns (address);

    function getPrev(address _id) external view returns (address);

    function validInsertPosition(uint256 _ICR, address _prevId, address _nextId) external view returns (bool);

    function findInsertPosition(uint256 _ICR, address _prevId, address _nextId) external view returns (address, address);
}

// File: contracts/Interfaces/IStabilityPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

/*
 * The Stability Pool holds THUSD tokens deposited by Stability Pool depositors.
 *
 * When a trove is liquidated, then depending on system conditions, some of its THUSD debt gets offset with
 * THUSD in the Stability Pool:  that is, the offset debt evaporates, and an equal amount of THUSD tokens in the Stability Pool is burned.
 *
 * Thus, a liquidation causes each depositor to receive a THUSD loss, in proportion to their deposit as a share of total deposits.
 * They also receive an collateral gain, as the collateral of the liquidated trove is distributed among Stability depositors,
 * in the same proportion.
 *
 * When a liquidation occurs, it depletes every deposit by the same fraction: for example, a liquidation that depletes 40%
 * of the total THUSD in the Stability Pool, depletes 40% of each deposit.
 *
 * A deposit that has experienced a series of liquidations is termed a "compounded deposit": each liquidation depletes the deposit,
 * multiplying it by some factor in range ]0,1[
 *
 * Please see the implementation spec in the proof document, which closely follows on from the compounded deposit / collateral gain derivations:
 * https://github.com/liquity/liquity/blob/master/papers/Scalable_Reward_Distribution_with_Compounding_Stakes.pdf
 *
 */
interface IStabilityPool {

    // --- Events ---

    event StabilityPoolCollateralBalanceUpdated(uint256 _newBalance);
    event StabilityPoolTHUSDBalanceUpdated(uint256 _newBalance);

    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event ActivePoolAddressChanged(address _newActivePoolAddress);
    event DefaultPoolAddressChanged(address _newDefaultPoolAddress);
    event THUSDTokenAddressChanged(address _newTHUSDTokenAddress);
    event SortedTrovesAddressChanged(address _newSortedTrovesAddress);
    event PriceFeedAddressChanged(address _newPriceFeedAddress);
    event CollateralAddressChanged(address _newCollateralAddress);

    event P_Updated(uint256 _P);
    event S_Updated(uint256 _S, uint128 _epoch, uint128 _scale);
    event EpochUpdated(uint128 _currentEpoch);
    event ScaleUpdated(uint128 _currentScale);

    event DepositSnapshotUpdated(address indexed _depositor, uint256 _P, uint256 _S);
    event UserDepositChanged(address indexed _depositor, uint256 _newDeposit);

    event CollateralGainWithdrawn(address indexed _depositor, uint256 _collateral, uint256 _THUSDLoss);
    event CollateralSent(address _to, uint256 _amount);

    // --- Functions ---

    /*
     * Called only once on init, to set addresses of other Liquity contracts
     * Callable only by owner, renounces ownership at the end
     */
    function setAddresses(
        address _borrowerOperationsAddress,
        address _troveManagerAddress,
        address _activePoolAddress,
        address _thusdTokenAddress,
        address _sortedTrovesAddress,
        address _priceFeedAddress,
        address _collateralAddress
    ) external;

    /*
     * Initial checks:
     * - _amount is not zero
     * ---
     * - Sends depositor's accumulated gains (collateral) to depositor
     */
    function provideToSP(uint256 _amount) external;

    /*
     * Initial checks:
     * - _amount is zero or there are no under collateralized troves left in the system
     * - User has a non zero deposit
     * ---
     * - Sends all depositor's accumulated gains (collateral) to depositor
     * - Decreases deposit stake, and takes new snapshot.
     *
     * If _amount > userDeposit, the user withdraws all of their compounded deposit.
     */
    function withdrawFromSP(uint256 _amount) external;

    /*
     * Initial checks:
     * - User has a non zero deposit
     * - User has an open trove
     * - User has some collateral gain
     * ---
     * - Transfers the depositor's entire collateral gain from the Stability Pool to the caller's trove
     * - Leaves their compounded deposit in the Stability Pool
     * - Updates snapshots for deposit
     */
    function withdrawCollateralGainToTrove(address _upperHint, address _lowerHint) external;

    /*
     * Initial checks:
     * - Caller is TroveManager
     * ---
     * Cancels out the specified debt against the THUSD contained in the Stability Pool (as far as possible)
     * and transfers the Trove's collateral from ActivePool to StabilityPool.
     * Only called by liquidation functions in the TroveManager.
     */
    function offset(uint256 _debt, uint256 _coll) external;

    /*
     * Returns the total amount of collateral held by the pool, accounted in an internal variable instead of `balance`,
     * to exclude edge cases like collateral received from a self-destruct.
     */
    function getCollateralBalance() external view returns (uint);

    /*
     * Returns THUSD held in the pool. Changes when users deposit/withdraw, and when Trove debt is offset.
     */
    function getTotalTHUSDDeposits() external view returns (uint);

    /*
     * Calculates the collateral gain earned by the deposit since its last snapshots were taken.
     */
    function getDepositorCollateralGain(address _depositor) external view returns (uint);

    /*
     * Return the user's compounded deposit.
     */
    function getCompoundedTHUSDDeposit(address _depositor) external view returns (uint);

    /*
     * Only callable by Active Pool, updates ERC20 tokens recieved
     */
    function updateCollateralBalance(uint256 _amount) external;
    /*
     * Fallback function
     * Only callable by Active Pool, it just accounts for ETH received
     * receive() external payable;
     */
    
    function collateralAddress() external view returns(address);
}

// File: contracts/Interfaces/ITHUSDToken.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "../Dependencies/IERC2612.sol";

interface ITHUSDToken is IERC20Metadata, IERC2612 {

    // --- Events ---

    event TroveManagerAddressAdded(address _troveManagerAddress);
    event StabilityPoolAddressAdded(address _newStabilityPoolAddress);
    event BorrowerOperationsAddressAdded(address _newBorrowerOperationsAddress);

    event THUSDTokenBalanceUpdated(address _user, uint256 _amount);

    // --- Functions ---
    function mintList(address contractAddress) external view returns (bool);
    function burnList(address contractAddress) external view returns (bool);

    function mint(address _account, uint256 _amount) external;

    function burn(address _account, uint256 _amount) external;

    function increaseAllowance(address spender, uint256 addedValue) external returns (bool);

    function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);
}

// File: contracts/Interfaces/ITroveManager.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.17;

import "./ILiquityBase.sol";
import "./IStabilityPool.sol";
import "./ITHUSDToken.sol";
import "./IPCV.sol";


// Common interface for the Trove Manager.
interface ITroveManager is ILiquityBase {

    enum Status {
        nonExistent,
        active,
        closedByOwner,
        closedByLiquidation,
        closedByRedemption
    }

    // --- Events ---

    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
    event PriceFeedAddressChanged(address _newPriceFeedAddress);
    event THUSDTokenAddressChanged(address _newTHUSDTokenAddress);
    event ActivePoolAddressChanged(address _activePoolAddress);
    event DefaultPoolAddressChanged(address _defaultPoolAddress);
    event StabilityPoolAddressChanged(address _stabilityPoolAddress);
    event GasPoolAddressChanged(address _gasPoolAddress);
    event CollSurplusPoolAddressChanged(address _collSurplusPoolAddress);
    event SortedTrovesAddressChanged(address _sortedTrovesAddress);
    event PCVAddressChanged(address _pcvAddress);

    event Liquidation(uint256 _liquidatedDebt, uint256 _liquidatedColl, uint256 _collGasCompensation, uint256 _THUSDGasCompensation);
    event Redemption(uint256 _attemptedTHUSDAmount, uint256 _actualTHUSDAmount, uint256 _collateralSent, uint256 _collateralFee);
    event TroveUpdated(address indexed _borrower, uint256 _debt, uint256 _coll, uint256 stake, uint8 operation);
    event TroveLiquidated(address indexed _borrower, uint256 _debt, uint256 _coll, uint8 operation);
    event BaseRateUpdated(uint256 _baseRate);
    event LastFeeOpTimeUpdated(uint256 _lastFeeOpTime);
    event TotalStakesUpdated(uint256 _newTotalStakes);
    event SystemSnapshotsUpdated(uint256 _totalStakesSnapshot, uint256 _totalCollateralSnapshot);
    event LTermsUpdated(uint256 _L_Collateral, uint256 _L_THUSDDebt);
    event TroveSnapshotsUpdated(uint256 _L_Collateral, uint256 _L_THUSDDebt);
    event TroveIndexUpdated(address _borrower, uint256 _newIndex);

    // --- Functions ---

    function setAddresses(
        address _borrowerOperationsAddress,
        address _activePoolAddress,
        address _defaultPoolAddress,
        address _stabilityPoolAddress,
        address _gasPoolAddress,
        address _collSurplusPoolAddress,
        address _priceFeedAddress,
        address _thusdTokenAddress,
        address _sortedTrovesAddress,
        address _pcvAddress
    ) external;

    function stabilityPool() external view returns (IStabilityPool);
    function thusdToken() external view returns (ITHUSDToken);
    function pcv() external view returns (IPCV);

    function getTroveOwnersCount() external view returns (uint);

    function getTroveFromTroveOwnersArray(uint256 _index) external view returns (address);

    function getNominalICR(address _borrower) external view returns (uint);
    function getCurrentICR(address _borrower, uint256 _price) external view returns (uint);

    function liquidate(address _borrower) external;

    function liquidateTroves(uint256 _n) external;

    function batchLiquidateTroves(address[] calldata _troveArray) external;

    function redeemCollateral(
        uint256 _THUSDAmount,
        address _firstRedemptionHint,
        address _upperPartialRedemptionHint,
        address _lowerPartialRedemptionHint,
        uint256 _partialRedemptionHintNICR,
        uint256 _maxIterations,
        uint256 _maxFee
    ) external;

    function updateStakeAndTotalStakes(address _borrower) external returns (uint);

    function updateTroveRewardSnapshots(address _borrower) external;

    function addTroveOwnerToArray(address _borrower) external returns (uint256 index);

    function applyPendingRewards(address _borrower) external;

    function getPendingCollateralReward(address _borrower) external view returns (uint);

    function getPendingTHUSDDebtReward(address _borrower) external view returns (uint);

     function hasPendingRewards(address _borrower) external view returns (bool);

    function getEntireDebtAndColl(address _borrower) external view returns (
        uint256 debt,
        uint256 coll,
        uint256 pendingTHUSDDebtReward,
        uint256 pendingCollateralReward
    );

    function closeTrove(address _borrower) external;

    function removeStake(address _borrower) external;

    function getRedemptionRate() external view returns (uint);
    function getRedemptionRateWithDecay() external view returns (uint);

    function getRedemptionFeeWithDecay(uint256 _collateralDrawn) external view returns (uint);

    function getBorrowingRate() external view returns (uint);
    function getBorrowingRateWithDecay() external view returns (uint);

    function getBorrowingFee(uint256 THUSDDebt) external view returns (uint);
    function getBorrowingFeeWithDecay(uint256 _THUSDDebt) external view returns (uint);

    function decayBaseRateFromBorrowing() external;

    function getTroveStatus(address _borrower) external view returns (Status);

    function getTroveStake(address _borrower) external view returns (uint);

    function getTroveDebt(address _borrower) external view returns (uint);

    function getTroveColl(address _borrower) external view returns (uint);

    function setTroveStatus(address _borrower, Status _status) external;

    function increaseTroveColl(address _borrower, uint256 _collIncrease) external returns (uint);

    function decreaseTroveColl(address _borrower, uint256 _collDecrease) external returns (uint);

    function increaseTroveDebt(address _borrower, uint256 _debtIncrease) external returns (uint);

    function decreaseTroveDebt(address _borrower, uint256 _collDecrease) external returns (uint);

    function getTCR(uint256 _price) external view returns (uint);

    function checkRecoveryMode(uint256 _price) external view returns (bool);
}