// File: contracts/ActivePool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

import "./Interfaces/IActivePool.sol";
import "./Interfaces/IDefaultPool.sol";
import "./Interfaces/IStabilityPoolManager.sol";
import "./Interfaces/IStabilityPool.sol";
import "./Interfaces/ICollSurplusPool.sol";
import "./Interfaces/IDeposit.sol";
import "./Dependencies/CheckContract.sol";
import "./Dependencies/SafetyTransfer.sol";
import "./Dependencies/Initializable.sol";

/*
 * The Active Pool holds the collaterals and DCHF debt (but not DCHF tokens) for all active troves.
 *
 * When a trove is liquidated, it's collateral and DCHF debt are transferred from the Active Pool, to either the
 * Stability Pool, the Default Pool, or both, depending on the liquidation conditions.
 *
 */
contract ActivePool is
	Ownable,
	ReentrancyGuard,
	CheckContract,
	Initializable,
	IActivePool
{
	using SafeERC20 for IERC20;
	using SafeMath for uint256;

	string public constant NAME = "ActivePool";
	address constant ETH_REF_ADDRESS = address(0);

	address public borrowerOperationsAddress;
	address public troveManagerAddress;
	address public troveManagerHelpersAddress;
	IDefaultPool public defaultPool;
	ICollSurplusPool public collSurplusPool;

	IStabilityPoolManager public stabilityPoolManager;

	bool public isInitialized;

	mapping(address => uint256) internal assetsBalance;
	mapping(address => uint256) internal DCHFDebts;

	// --- Contract setters ---

	function setAddresses(
		address _borrowerOperationsAddress,
		address _troveManagerAddress,
		address _troveManagerHelpersAddress,
		address _stabilityManagerAddress,
		address _defaultPoolAddress,
		address _collSurplusPoolAddress
	) external initializer onlyOwner {
		require(!isInitialized, "Already initialized");
		checkContract(_borrowerOperationsAddress);
		checkContract(_troveManagerAddress);
		checkContract(_troveManagerHelpersAddress);
		checkContract(_stabilityManagerAddress);
		checkContract(_defaultPoolAddress);
		checkContract(_collSurplusPoolAddress);
		isInitialized = true;

		borrowerOperationsAddress = _borrowerOperationsAddress;
		troveManagerAddress = _troveManagerAddress;
		troveManagerHelpersAddress = _troveManagerHelpersAddress;
		stabilityPoolManager = IStabilityPoolManager(_stabilityManagerAddress);
		defaultPool = IDefaultPool(_defaultPoolAddress);
		collSurplusPool = ICollSurplusPool(_collSurplusPoolAddress);

		emit BorrowerOperationsAddressChanged(_borrowerOperationsAddress);
		emit TroveManagerAddressChanged(_troveManagerAddress);
		emit StabilityPoolAddressChanged(_stabilityManagerAddress);
		emit DefaultPoolAddressChanged(_defaultPoolAddress);

		renounceOwnership();
	}

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

	/*
	 * Returns the ETH state variable.
	 *
	 *Not necessarily equal to the the contract's raw ETH balance - ether can be forcibly sent to contracts.
	 */
	function getAssetBalance(address _asset) external view override returns (uint256) {
		return assetsBalance[_asset];
	}

	function getDCHFDebt(address _asset) external view override returns (uint256) {
		return DCHFDebts[_asset];
	}

	// --- Pool functionality ---

	function sendAsset(
		address _asset,
		address _account,
		uint256 _amount
	) external override nonReentrant callerIsBOorTroveMorSP {
		if (stabilityPoolManager.isStabilityPool(msg.sender)) {
			assert(address(stabilityPoolManager.getAssetStabilityPool(_asset)) == msg.sender);
		}

		uint256 safetyTransferAmount = SafetyTransfer.decimalsCorrection(_asset, _amount);
		if (safetyTransferAmount == 0) return;

		assetsBalance[_asset] = assetsBalance[_asset].sub(_amount);

		if (_asset != ETH_REF_ADDRESS) {
			IERC20(_asset).safeTransfer(_account, safetyTransferAmount);

			if (isERC20DepositContract(_account)) {
				IDeposit(_account).receivedERC20(_asset, _amount);
			}
		} else {
			(bool success, ) = _account.call{ value: _amount }("");
			require(success, "ActivePool: sending ETH failed");
		}

		emit ActivePoolAssetBalanceUpdated(_asset, assetsBalance[_asset]);
		emit AssetSent(_account, _asset, safetyTransferAmount);
	}

	function isERC20DepositContract(address _account) private view returns (bool) {
		return (_account == address(defaultPool) ||
			_account == address(collSurplusPool) ||
			stabilityPoolManager.isStabilityPool(_account));
	}

	function increaseDCHFDebt(address _asset, uint256 _amount)
		external
		override
		callerIsBOorTroveM
	{
		DCHFDebts[_asset] = DCHFDebts[_asset].add(_amount);
		emit ActivePoolDCHFDebtUpdated(_asset, DCHFDebts[_asset]);
	}

	function decreaseDCHFDebt(address _asset, uint256 _amount)
		external
		override
		callerIsBOorTroveMorSP
	{
		DCHFDebts[_asset] = DCHFDebts[_asset].sub(_amount);
		emit ActivePoolDCHFDebtUpdated(_asset, DCHFDebts[_asset]);
	}

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

	modifier callerIsBorrowerOperationOrDefaultPool() {
		require(
			msg.sender == borrowerOperationsAddress || msg.sender == address(defaultPool),
			"ActivePool: Caller is neither BO nor Default Pool"
		);

		_;
	}

	modifier callerIsBOorTroveMorSP() {
		require(
			msg.sender == borrowerOperationsAddress ||
				msg.sender == troveManagerAddress ||
				msg.sender == troveManagerHelpersAddress ||
				stabilityPoolManager.isStabilityPool(msg.sender),
			"ActivePool: Caller is neither BorrowerOperations nor TroveManager nor StabilityPool"
		);
		_;
	}

	modifier callerIsBOorTroveM() {
		require(
			msg.sender == borrowerOperationsAddress || 
			msg.sender == troveManagerAddress ||
			msg.sender == troveManagerHelpersAddress,
			"ActivePool: Caller is neither BorrowerOperations nor TroveManager"
		);

		_;
	}

	function receivedERC20(address _asset, uint256 _amount)
		external
		override
		callerIsBorrowerOperationOrDefaultPool
	{
		assetsBalance[_asset] = assetsBalance[_asset].add(_amount);
		emit ActivePoolAssetBalanceUpdated(_asset, assetsBalance[_asset]);
	}

	// --- Fallback function ---

	receive() external payable callerIsBorrowerOperationOrDefaultPool {
		assetsBalance[ETH_REF_ADDRESS] = assetsBalance[ETH_REF_ADDRESS].add(msg.value);
		emit ActivePoolAssetBalanceUpdated(ETH_REF_ADDRESS, assetsBalance[ETH_REF_ADDRESS]);
	}
}

// File: @openzeppelin/contracts/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // 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 (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @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) {
        return a + b;
    }

    /**
     * @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 a - b;
    }

    /**
     * @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) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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 a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting 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.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../utils/Context.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.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * 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.
 */
abstract contract Ownable is Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

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

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

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(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");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: contracts/Interfaces/IActivePool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;
import "./IPool.sol";

interface IActivePool is IPool {
	// --- Events ---
	event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
	event TroveManagerAddressChanged(address _newTroveManagerAddress);
	event ActivePoolDCHFDebtUpdated(address _asset, uint256 _DCHFDebt);
	event ActivePoolAssetBalanceUpdated(address _asset, uint256 _balance);

	// --- Functions ---
	function sendAsset(
		address _asset,
		address _account,
		uint256 _amount
	) external;
}

// File: contracts/Interfaces/IDefaultPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;
import "./IPool.sol";

interface IDefaultPool is IPool {
	// --- Events ---
	event TroveManagerAddressChanged(address _newTroveManagerAddress);
	event DefaultPoolDCHFDebtUpdated(address _asset, uint256 _DCHFDebt);
	event DefaultPoolAssetBalanceUpdated(address _asset, uint256 _balance);

	// --- Functions ---
	function sendAssetToActivePool(address _asset, uint256 _amount) external;
}

// File: contracts/Interfaces/IStabilityPoolManager.sol



pragma solidity ^0.8.14;

import "./IStabilityPool.sol";

interface IStabilityPoolManager {
	event StabilityPoolAdded(address asset, address stabilityPool);
	event StabilityPoolRemoved(address asset, address stabilityPool);

	function isStabilityPool(address stabilityPool) external view returns (bool);

	function addStabilityPool(address asset, address stabilityPool) external;

	function getAssetStabilityPool(address asset) external view returns (IStabilityPool);

	function unsafeGetAssetStabilityPool(address asset) external view returns (address);
}

// File: contracts/Interfaces/IStabilityPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;

import "./IDeposit.sol";

interface IStabilityPool is IDeposit {
	// --- Events ---
	event StabilityPoolAssetBalanceUpdated(uint256 _newBalance);
	event StabilityPoolDCHFBalanceUpdated(uint256 _newBalance);

	event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
	event TroveManagerAddressChanged(address _newTroveManagerAddress);
	event DefaultPoolAddressChanged(address _newDefaultPoolAddress);
	event DCHFTokenAddressChanged(address _newDCHFTokenAddress);
	event SortedTrovesAddressChanged(address _newSortedTrovesAddress);
	event CommunityIssuanceAddressChanged(address _newCommunityIssuanceAddress);

	event P_Updated(uint256 _P);
	event S_Updated(uint256 _S, uint128 _epoch, uint128 _scale);
	event G_Updated(uint256 _G, uint128 _epoch, uint128 _scale);
	event EpochUpdated(uint128 _currentEpoch);
	event ScaleUpdated(uint128 _currentScale);

	event DepositSnapshotUpdated(address indexed _depositor, uint256 _P, uint256 _S, uint256 _G);
	event SystemSnapshotUpdated(uint256 _P, uint256 _G);
	event UserDepositChanged(address indexed _depositor, uint256 _newDeposit);
	event StakeChanged(uint256 _newSystemStake, address _depositor);

	event AssetGainWithdrawn(address indexed _depositor, uint256 _Asset, uint256 _DCHFLoss);
	event MONPaidToDepositor(address indexed _depositor, uint256 _MON);
	event AssetSent(address _to, uint256 _amount);

	// --- Functions ---

	function NAME() external view returns (string memory name);

	/*
	 * Called only once on init, to set addresses of other Dfranc contracts
	 * Callable only by owner, renounces ownership at the end
	 */
	function setAddresses(
		address _assetAddress,
		address _borrowerOperationsAddress,
		address _troveManagerAddress,
		address _troveManagerHelperAddress,
		address _dchfTokenAddress,
		address _sortedTrovesAddress,
		address _communityIssuanceAddress,
		address _dfrancParamsAddress
	) external;

	/*
	 * Initial checks:
	 * - Frontend is registered or zero address
	 * - Sender is not a registered frontend
	 * - _amount is not zero
	 * ---
	 * - Triggers a MON issuance, based on time passed since the last issuance. The MON issuance is shared between *all* depositors and front ends
	 * - Tags the deposit with the provided front end tag param, if it's a new deposit
	 * - Sends depositor's accumulated gains (MON, ETH) to depositor
	 * - Sends the tagged front end's accumulated MON gains to the tagged front end
	 * - Increases deposit and tagged front end's stake, and takes new snapshots for each.
	 */
	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
	 * ---
	 * - Triggers a MON issuance, based on time passed since the last issuance. The MON issuance is shared between *all* depositors and front ends
	 * - Removes the deposit's front end tag if it is a full withdrawal
	 * - Sends all depositor's accumulated gains (MON, ETH) to depositor
	 * - Sends the tagged front end's accumulated MON gains to the tagged front end
	 * - Decreases deposit and tagged front end's stake, and takes new snapshots for each.
	 *
	 * 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 ETH gain
	 * ---
	 * - Triggers a MON issuance, based on time passed since the last issuance. The MON issuance is shared between *all* depositors and front ends
	 * - Sends all depositor's MON gain to  depositor
	 * - Sends all tagged front end's MON gain to the tagged front end
	 * - Transfers the depositor's entire ETH gain from the Stability Pool to the caller's trove
	 * - Leaves their compounded deposit in the Stability Pool
	 * - Updates snapshots for deposit and tagged front end stake
	 */
	function withdrawAssetGainToTrove(address _upperHint, address _lowerHint) external;

	/*
	 * Initial checks:
	 * - Caller is TroveManager
	 * ---
	 * Cancels out the specified debt against the DCHF contained in the Stability Pool (as far as possible)
	 * and transfers the Trove's ETH 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 ETH held by the pool, accounted in an internal variable instead of `balance`,
	 * to exclude edge cases like ETH received from a self-destruct.
	 */
	function getAssetBalance() external view returns (uint256);

	/*
	 * Returns DCHF held in the pool. Changes when users deposit/withdraw, and when Trove debt is offset.
	 */
	function getTotalDCHFDeposits() external view returns (uint256);

	/*
	 * Calculates the ETH gain earned by the deposit since its last snapshots were taken.
	 */
	function getDepositorAssetGain(address _depositor) external view returns (uint256);

	/*
	 * Calculate the MON gain earned by a deposit since its last snapshots were taken.
	 * If not tagged with a front end, the depositor gets a 100% cut of what their deposit earned.
	 * Otherwise, their cut of the deposit's earnings is equal to the kickbackRate, set by the front end through
	 * which they made their deposit.
	 */
	function getDepositorMONGain(address _depositor) external view returns (uint256);

	/*
	 * Return the user's compounded deposit.
	 */
	function getCompoundedDCHFDeposit(address _depositor) external view returns (uint256);

	/*
	 * Return the front end's compounded stake.
	 *
	 * The front end's compounded stake is equal to the sum of its depositors' compounded deposits.
	 */
	function getCompoundedTotalStake() external view returns (uint256);

	function getNameBytes() external view returns (bytes32);

	function getAssetType() external view returns (address);

	/*
	 * Fallback function
	 * Only callable by Active Pool, it just accounts for ETH received
	 * receive() external payable;
	 */
}

// File: contracts/Interfaces/ICollSurplusPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;

import "./IDeposit.sol";

interface ICollSurplusPool is IDeposit {
	// --- Events ---

	event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
	event TroveManagerAddressChanged(address _newTroveManagerAddress);
	event ActivePoolAddressChanged(address _newActivePoolAddress);

	event CollBalanceUpdated(address indexed _account, uint256 _newBalance);
	event AssetSent(address _to, uint256 _amount);

	// --- Contract setters ---

	function setAddresses(
		address _borrowerOperationsAddress,
		address _troveManagerAddress,
		address _troveManagerHelpersAddress,
		address _activePoolAddress
	) external;

	function getAssetBalance(address _asset) external view returns (uint256);

	function getCollateral(address _asset, address _account) external view returns (uint256);

	function accountSurplus(
		address _asset,
		address _account,
		uint256 _amount
	) external;

	function claimColl(address _asset, address _account) external;
}

// File: contracts/Interfaces/IDeposit.sol



pragma solidity ^0.8.14;

interface IDeposit {
	function receivedERC20(address _asset, uint256 _amount) external;
}

// File: contracts/Dependencies/CheckContract.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;

contract CheckContract {
	function checkContract(address _account) internal view {
		require(_account != address(0), "Account cannot be zero address");

		uint256 size;
		assembly {
			size := extcodesize(_account)
		}
		require(size > 0, "Account code size cannot be zero");
	}
}

// File: contracts/Dependencies/SafetyTransfer.sol



import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "./ERC20Decimals.sol";

library SafetyTransfer {
	using SafeMath for uint256;

	//_amount is in ether (1e18) and we want to convert it to the token decimal
	function decimalsCorrection(address _token, uint256 _amount)
		internal
		view
		returns (uint256)
	{
		if (_token == address(0)) return _amount;
		if (_amount == 0) return 0;

		uint8 decimals = ERC20Decimals(_token).decimals();
		if (decimals < 18) {
			return _amount.div(10**(18 - decimals));
		} else {
			return _amount.mul(10**(decimals - 18));
		}
	}
}

// File: contracts/Dependencies/Initializable.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts/utils/Address.sol";

abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts. Equivalent to `reinitializer(1)`.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!Address.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * `initializer` is equivalent to `reinitializer(1)`, so a reinitializer may be used after the original
     * initialization step. This is essential to configure modules that are added through upgrades and that require
     * initialization.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Internal function that returns the initialized version. Returns `_initialized`
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Internal function that returns the initialized version. Returns `_initializing`
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

// File: contracts/Interfaces/IPool.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.14;

import "./IDeposit.sol";

// Common interface for the Pools.
interface IPool is IDeposit {
	// --- Events ---

	event AssetBalanceUpdated(uint256 _newBalance);
	event DCHFBalanceUpdated(uint256 _newBalance);
	event ActivePoolAddressChanged(address _newActivePoolAddress);
	event DefaultPoolAddressChanged(address _newDefaultPoolAddress);
	event AssetAddressChanged(address _assetAddress);
	event StabilityPoolAddressChanged(address _newStabilityPoolAddress);
	event AssetSent(address _to, address indexed _asset, uint256 _amount);

	// --- Functions ---

	function getAssetBalance(address _asset) external view returns (uint256);

	function getDCHFDebt(address _asset) external view returns (uint256);

	function increaseDCHFDebt(address _asset, uint256 _amount) external;

	function decreaseDCHFDebt(address _asset, uint256 _amount) external;
}

// File: contracts/Dependencies/ERC20Decimals.sol



pragma solidity ^0.8.14;

interface ERC20Decimals {
	function decimals() external view returns (uint8);
}