// Contract: DefaultPool
// Target function: function _requireCallerIsActivePool() internal view
, ETH) to depositor
     * - Sends the tagged front end's accumulated RBST 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(uint _amount) external;

    /*
     * Initial checks:
     * - User has a non zero deposit
     * - User has an open trove
     * - User has some ETH gain
     * ---
     * - Triggers a RBST issuance, based on time passed since the last issuance. The RBST issuance is shared between *all* depositors and front ends
     * - Sends all depositor's RBST gain to  depositor
     * - Sends all tagged front end's RBST 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 withdrawETHGainToTrove(address _upperHint, address _lowerHint) external;

    /*
     * Initial checks:
     * - Frontend (sender) not already registered
     * - User (sender) has no deposit
     * - _kickbackRate is in the range [0, 100%]
     * ---
     * Front end makes a one-time selection of kickback rate upon registering
     */
    function registerFrontEnd(uint _kickbackRate) external;

    /*
     * Initial checks:
     * - Caller is TroveManager
     * ---
     * Cancels out the specified debt against the RUBC 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(uint _debt, uint _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 getETH() external view returns (uint);

    /*
     * Returns RUBC held in the pool. Changes when users deposit/withdraw, and when Trove debt is offset.
     */
    function getTotalRUBCDeposits() external view returns (uint);

    /*
     * Calculates the ETH gain earned by the deposit since its last snapshots were taken.
     */
    function getDepositorETHGain(address _depositor) external view returns (uint);

    /*
     * Calculate the RBST 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 getDepositorRBSTGain(address _depositor) external view returns (uint);

    /*
     * Return the RBST gain earned by the front end.
     */
    function getFrontEndRBSTGain(address _frontEnd) external view returns (uint);

    /*
     * Return the user's compounded deposit.
     */
    function getCompoundedRUBCDeposit(address _depositor) external view returns (uint);

    /*
     * Return the front end's compounded stake.
     *
     * The front end's compounded stake is equal to the sum of its depositors' compounded deposits.
     */
    function getCompoundedFrontEndStake(address _frontEnd) external view returns (uint);

    /*
     * Fallback function
     * Only callable by Active Pool, it just accounts for ETH received
     * receive() external payable;
     */
}

interface ITellorCaller {
    function getTellorCurrentValue(uint256 _requestId) external view returns (bool, uint256, uint256);
}

contract TellorCaller is ITellorCaller {
    using SafeMath for uint256;

    ITellor public tellor;

    constructor (address _tellorMasterAddress) public {
        tellor = ITellor(_tellorMasterAddress);
    }

    /*
    * getTellorCurrentValue(): identical to getCurrentValue() in UsingTellor.sol
    *
    * @dev Allows the user to get the latest value for the requestId specified
    * @param _requestId is the requestId to look up the value for
    * @return ifRetrieve bool true if it is able to retrieve a value, the value, and the value's timestamp
    * @return value the value retrieved
    * @return _timestampRetrieved the value's timestamp
    */
    function getTellorCurrentValue(uint256 _requestId)
        external
        view
        override
        returns (
            bool ifRetrieve,
            uint256 value,
            uint256 _timestampRetrieved
        )
    {
        uint256 _count = tellor.getNewValueCountbyRequestId(_requestId);
        uint256 _time =
            tellor.getTimestampbyRequestIDandIndex(_requestId, _count.sub(1));
        uint256 _value = tellor.retrieveData(_requestId, _time);
        if (_value > 0) return (true, _value, _time);
        return (false, 0, _time);
    }
}

interface IActivePool is IPool {
    // --- Events ---
    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event ActivePoolRUBCDebtUpdated(uint _RUBCDebt);
    event ActivePoolETHBalanceUpdated(uint _ETH);

    // --- Functions ---
    function sendETH(address _account, uint _amount) external;
}

interface IDefaultPool is IPool {
    // --- Events ---
    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event DefaultPoolRUBCDebtUpdated(uint _RUBCDebt);
    event DefaultPoolETHBalanceUpdated(uint _ETH);

    // --- Functions ---
    function sendETHToActivePool(uint _amount) external;
}

interface ILiquityBase {
    function priceFeed() external view returns (IPriceFeed);
}

interface ITroveManager is ILiquityBase {
    
    // --- Events ---

    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
    event PriceFeedAddressChanged(address _newPriceFeedAddress);
    event RUBCAddressChanged(address _newRUBCAddress);
    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 RBSTAddressChanged(address _rbstAddress);
    event RBSTStakingAddressChanged(address _rbstStakingAddress);

    event Liquidation(uint _liquidatedDebt, uint _liquidatedColl, uint _collGasCompensation, uint _RUBCGasCompensation);
    event Redemption(uint _attemptedRUBCAmount, uint _actualRUBCAmount, uint _ETHSent, uint _ETHFee);
    event TroveUpdated(address indexed _borrower, uint _debt, uint _coll, uint stake, uint8 operation);
    event TroveLiquidated(address indexed _borrower, uint _debt, uint _coll, uint8 operation);
    event BaseRateUpdated(uint _baseRate);
    event LastFeeOpTimeUpdated(uint _lastFeeOpTime);
    event TotalStakesUpdated(uint _newTotalStakes);
    event SystemSnapshotsUpdated(uint _totalStakesSnapshot, uint _totalCollateralSnapshot);
    event LTermsUpdated(uint _L_ETH, uint _L_RUBCDebt);
    event TroveSnapshotsUpdated(uint _L_ETH, uint _L_RUBCDebt);
    event TroveIndexUpdated(address _borrower, uint _newIndex);

    // --- Functions ---

    function setAddresses(
        address _borrowerOperationsAddress,
        address _activePoolAddress,
        address _defaultPoolAddress,
        address _stabilityPoolAddress,
        address _gasPoolAddress,
        address _collSurplusPoolAddress,
        address _priceFeedAddress,
        address _rubcAddress,
        address _sortedTrovesAddress,
        address _rbstAddress,
        address _rbstStakingAddress
    ) external;

    function stabilityPool() external view returns (IStabilityPool);
    function rubc() external view returns (IRUBC);
    function rbst() external view returns (IRBST);
    function rbstStaking() external view returns (IRBSTStaking);

    function getTroveOwnersCount() external view returns (uint);

    function getTroveFromTroveOwnersArray(uint _index) external view returns (address);

    function getNominalICR(address _borrower) external view returns (uint);
    function getCurrentICR(address _borrower, uint _price) external view returns (uint);

    function liquidate(address _borrower) external;

    function liquidateTroves(uint _n) external;

    function batchLiquidateTroves(address[] calldata _troveArray) external;

    function redeemCollateral(
        uint _RUBCAmount,
        address _firstRedemptionHint,
        address _upperPartialRedemptionHint,
        address _lowerPartialRedemptionHint,
        uint _partialRedemptionHintNICR,
        uint _maxIterations,
        uint _maxFee
    ) external; 

    function updateStakeAndTotalStakes(address _borrower) external returns (uint);

    function updateTroveRewardSnapshots(address _borrower) external;

    function addTroveOwnerToArray(address _borrower) external returns (uint index);

    function applyPendingRewards(address _borrower) external;

    function getPendingETHReward(address _borrower) external view returns (uint);

    function getPendingRUBCDebtReward(address _borrower) external view returns (uint);

     function hasPendingRewards(address _borrower) external view returns (bool);

    function getEntireDebtAndColl(address _borrower) external view returns (
        uint debt, 
        uint coll, 
        uint pendingRUBCDebtReward, 
        uint pendingETHReward
    );

    function closeTrove(address _borrower) external;

    function removeStake(address _borrower) external;

    function getRedemptionRate() external view returns (uint);
    function getRedemptionRateWithDecay() external view returns (uint);

    function getRedemptionFeeWithDecay(uint _ETHDrawn) external view returns (uint);

    function getBorrowingRate() external view returns (uint);
    function getBorrowingRateWithDecay() external view returns (uint);

    function getBorrowingFee(uint RUBCDebt) external view returns (uint);
    function getBorrowingFeeWithDecay(uint _RUBCDebt) external view returns (uint);

    function decayBaseRateFromBorrowing() external;

    function getTroveStatus(address _borrower) external view returns (uint);
    
    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, uint num) external;

    function increaseTroveColl(address _borrower, uint _collIncrease) external returns (uint);

    function decreaseTroveColl(address _borrower, uint _collDecrease) external returns (uint); 

    function increaseTroveDebt(address _borrower, uint _debtIncrease) external returns (uint); 

    function decreaseTroveDebt(address _borrower, uint _collDecrease) external returns (uint); 

    function getTCR(uint _price) external view returns (uint);

    function checkRecoveryMode(uint _price) external view returns (bool);
}

contract LiquityBase is BaseMath, ILiquityBase {
    using SafeMath for uint;

    uint constant public _100pct = 1000000000000000000; // 1e18 == 100%

    // Minimum collateral ratio for individual troves
    uint constant public MCR = 1100000000000000000; // 110%

    // Critical system collateral ratio. If the system's total collateral ratio (TCR) falls below the CCR, Recovery Mode is triggered.
    uint constant public CCR = 1500000000000000000; // 150%

    // Amount of RUBC to be locked in gas pool on opening troves
    uint constant public RUBC_GAS_COMPENSATION = 20_000e18;

    // Minimum amount of net RUBC debt a trove must have
    uint constant public MIN_NET_DEBT = 100_000e18;

    uint constant public PERCENT_DIVISOR = 200; // dividing by 200 yields 0.5%

    uint 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(uint _debt) internal pure returns (uint) {
        return _debt.add(RUBC_GAS_COMPENSATION);
    }

    function _getNetDebt(uint _debt) internal pure returns (uint) {
        return _debt.sub(RUBC_GAS_COMPENSATION);
    }

    // Return the amount of ETH to be drawn from a trove's collateral and sent as gas compensation.
    function _getCollGasCompensation(uint _entireColl) internal pure returns (uint) {
        return _entireColl / PERCENT_DIVISOR;
    }

    function getEntireSystemColl() public view returns (uint entireSystemColl) {
        uint activeColl = activePool.getETH();
        uint liquidatedColl = defaultPool.getETH();

        return activeColl.add(liquidatedColl);
    }

    function getEntireSystemDebt() public view returns (uint entireSystemDebt) {
        uint activeDebt = activePool.getRUBCDebt();
        uint closedDebt = defaultPool.getRUBCDebt();

        return activeDebt.add(closedDebt);
    }

    function _getTCR(uint _price) internal view returns (uint TCR) {
        uint entireSystemColl = getEntireSystemColl();
        uint entireSystemDebt = getEntireSystemDebt();

        TCR = LiquityMath._computeCR(entireSystemColl, entireSystemDebt, _price);

        return TCR;
    }

    function _checkRecoveryMode(uint _price) internal view returns (bool) {
        uint TCR = _getTCR(_price);

        return TCR < CCR;
    }

    function _requireUserAcceptsFee(uint _fee, uint _amount, uint _maxFeePercentage) internal pure {
        uint feePercentage = _fee.mul(DECIMAL_PRECISION).div(_amount);
        require(feePercentage <= _maxFeePercentage, "Fee exceeded provided maximum");
    }
}


/*
 * The Default Pool holds the ETH and RUBC debt (but not RUBC tokens) from liquidations that have been redistributed
 * to active troves but not yet "applied", i.e. not yet recorded on a recipient active trove's struct.
 *
 * When a trove makes an operation that applies its pending ETH and RUBC debt, its pending ETH and RUBC debt is moved
 * from the Default Pool to the Active Pool.
 */
contract DefaultPool is Ownable, CheckContract, IDefaultPool {
    using SafeMath for uint256;

    string constant public NAME = "DefaultPool";

    address public troveManagerAddress;
    address public activePoolAddress;
    uint256 internal ETH;  // deposited ETH tracker
    uint256 internal RUBCDebt;  // debt

    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event DefaultPoolRUBCDebtUpdated(uint _RUBCDebt);
    event DefaultPoolETHBalanceUpdated(uint _ETH);

    // --- Dependency setters ---

    function setAddresses(
        address _troveManagerAddress,
        address _activePoolAddress
    )
        external
        onlyOwner
    {
        checkContract(_troveManagerAddress);
        checkContract(_activePoolAddress);

        troveManagerAddress = _troveManagerAddress;
        activePoolAddress = _activePoolAddress;

        emit TroveManagerAddressChanged(_troveManagerAddress);
        emit ActivePoolAddressChanged(_activePoolAddress);

        _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 getETH() external view override returns (uint) {
        return ETH;
    }

    function getRUBCDebt() external view override returns (uint) {
        return RUBCDebt;
    }

    // --- Pool functionality ---

    function sendETHToActivePool(uint _amount) external override {
        _requireCallerIsTroveManager();
        address activePool = activePoolAddress; // cache to save an SLOAD
        ETH = ETH.sub(_amount);
        emit DefaultPoolETHBalanceUpdated(ETH);
        emit EtherSent(activePool, _amount);

        (bool success, ) = activePool.call{ value: _amount }("");
        require(success, "DefaultPool: sending ETH failed");
    }

    function increaseRUBCDebt(uint _amount) external override {
        _requireCallerIsTroveManager();
        RUBCDebt = RUBCDebt.add(_amount);
        emit DefaultPoolRUBCDebtUpdated(RUBCDebt);
    }

    function decreaseRUBCDebt(uint _amount) external override {
        _requireCallerIsTroveManager();
        RUBCDebt = RUBCDebt.sub(_amount);
        emit DefaultPoolRUBCDebtUpdated(RUBCDebt);
    }