// Contract: BorrowerOperations
// Target function: function _triggerBorrowingFee(ITroveManager _troveManager, IRUBC _rubc, uint _RUBCAmount, uint _maxFeePercentage) internal returns (uint)
 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");
    }
}


contract BorrowerOperations is LiquityBase, Ownable, CheckContract, IBorrowerOperations {
    string constant public NAME = "BorrowerOperations";

    // --- Connected contract declarations ---

    ITroveManager public troveManager;

    address stabilityPoolAddress;

    address gasPoolAddress;

    ICollSurplusPool collSurplusPool;

    IRBSTStaking public rbstStaking;
    address public rbstStakingAddress;

    IRUBC public rubc;

    // A doubly linked list of Troves, sorted by their collateral ratios
    ISortedTroves public sortedTroves;

    /* --- Variable container structs  ---

    Used to hold, return and assign variables inside a function, in order to avoid the error:
    "CompilerError: Stack too deep". */

     struct LocalVariables_adjustTrove {
        uint price;
        uint collChange;
        uint netDebtChange;
        bool isCollIncrease;
        uint debt;
        uint coll;
        uint oldICR;
        uint newICR;
        uint newTCR;
        uint RUBCFee;
        uint newDebt;
        uint newColl;
        uint stake;
    }

    struct LocalVariables_openTrove {
        uint price;
        uint RUBCFee;
        uint netDebt;
        uint compositeDebt;
        uint ICR;
        uint NICR;
        uint stake;
        uint arrayIndex;
    }

    struct ContractsCache {
        ITroveManager troveManager;
        IActivePool activePool;
        IRUBC rubc;
    }

    enum BorrowerOperation {
        openTrove,
        closeTrove,
        adjustTrove
    }

    event TroveManagerAddressChanged(address _newTroveManagerAddress);
    event ActivePoolAddressChanged(address _activePoolAddress);
    event DefaultPoolAddressChanged(address _defaultPoolAddress);
    event StabilityPoolAddressChanged(address _stabilityPoolAddress);
    event GasPoolAddressChanged(address _gasPoolAddress);
    event CollSurplusPoolAddressChanged(address _collSurplusPoolAddress);
    event PriceFeedAddressChanged(address  _newPriceFeedAddress);
    event SortedTrovesAddressChanged(address _sortedTrovesAddress);
    event RUBCAddressChanged(address _rubcAddress);
    event RBSTStakingAddressChanged(address _rbstStakingAddress);

    event TroveCreated(address indexed _borrower, uint arrayIndex);
    event TroveUpdated(address indexed _borrower, uint _debt, uint _coll, uint stake, BorrowerOperation operation);
    event RUBCBorrowingFeePaid(address indexed _borrower, uint _RUBCFee);
    
    // --- Dependency setters ---

    function setAddresses(
        address _troveManagerAddress,
        address _activePoolAddress,
        address _defaultPoolAddress,
        address _stabilityPoolAddress,
        address _gasPoolAddress,
        address _collSurplusPoolAddress,
        address _priceFeedAddress,
        address _sortedTrovesAddress,
        address _rubcAddress,
        address _rbstStakingAddress
    )
        external
        override
        onlyOwner
    {
        // This makes impossible to open a trove with zero withdrawn RUBC
        assert(MIN_NET_DEBT > 0);

        checkContract(_troveManagerAddress);
        checkContract(_activePoolAddress);
        checkContract(_defaultPoolAddress);
        checkContract(_stabilityPoolAddress);
        checkContract(_gasPoolAddress);
        checkContract(_collSurplusPoolAddress);
        checkContract(_priceFeedAddress);
        checkContract(_sortedTrovesAddress);
        checkContract(_rubcAddress);
        checkContract(_rbstStakingAddress);

        troveManager = ITroveManager(_troveManagerAddress);
        activePool = IActivePool(_activePoolAddress);
        defaultPool = IDefaultPool(_defaultPoolAddress);
        stabilityPoolAddress = _stabilityPoolAddress;
        gasPoolAddress = _gasPoolAddress;
        collSurplusPool = ICollSurplusPool(_collSurplusPoolAddress);
        priceFeed = IPriceFeed(_priceFeedAddress);
        sortedTroves = ISortedTroves(_sortedTrovesAddress);
        rubc = IRUBC(_rubcAddress);
        rbstStakingAddress = _rbstStakingAddress;
        rbstStaking = IRBSTStaking(_rbstStakingAddress);

        emit TroveManagerAddressChanged(_troveManagerAddress);
        emit ActivePoolAddressChanged(_activePoolAddress);
        emit DefaultPoolAddressChanged(_defaultPoolAddress);
        emit StabilityPoolAddressChanged(_stabilityPoolAddress);
        emit GasPoolAddressChanged(_gasPoolAddress);
        emit CollSurplusPoolAddressChanged(_collSurplusPoolAddress);
        emit PriceFeedAddressChanged(_priceFeedAddress);
        emit SortedTrovesAddressChanged(_sortedTrovesAddress);
        emit RUBCAddressChanged(_rubcAddress);
        emit RBSTStakingAddressChanged(_rbstStakingAddress);

        _renounceOwnership();
    }

    // --- Borrower Trove Operations ---

    function openTrove(uint _maxFeePercentage, uint _RUBCAmount, address _upperHint, address _lowerHint) external payable override {
        ContractsCache memory contractsCache = ContractsCache(troveManager, activePool, rubc);
        LocalVariables_openTrove memory vars;

        vars.price = priceFeed.fetchPrice();
        bool isRecoveryMode = _checkRecoveryMode(vars.price);

        _requireValidMaxFeePercentage(_maxFeePercentage, isRecoveryMode);
        _requireTroveisNotActive(contractsCache.troveManager, msg.sender);

        vars.RUBCFee;
        vars.netDebt = _RUBCAmount;

        if (!isRecoveryMode) {
            vars.RUBCFee = _triggerBorrowingFee(contractsCache.troveManager, contractsCache.rubc, _RUBCAmount, _maxFeePercentage);
            vars.netDebt = vars.netDebt.add(vars.RUBCFee);
        }
        _requireAtLeastMinNetDebt(vars.netDebt);

        // ICR is based on the composite debt, i.e. the requested RUBC amount + RUBC borrowing fee + RUBC gas comp.
        vars.compositeDebt = _getCompositeDebt(vars.netDebt);
        assert(vars.compositeDebt > 0);
        
        vars.ICR = LiquityMath._computeCR(msg.value, vars.compositeDebt, vars.price);
        vars.NICR = LiquityMath._computeNominalCR(msg.value, vars.compositeDebt);

        if (isRecoveryMode) {
            _requireICRisAboveCCR(vars.ICR);
        } else {
            _requireICRisAboveMCR(vars.ICR);
            uint newTCR = _getNewTCRFromTroveChange(msg.value, true, vars.compositeDebt, true, vars.price);  // bools: coll increase, debt increase
            _requireNewTCRisAboveCCR(newTCR); 
        }

        // Set the trove struct's properties
        contractsCache.troveManager.setTroveStatus(msg.sender, 1);
        contractsCache.troveManager.increaseTroveColl(msg.sender, msg.value);
        contractsCache.troveManager.increaseTroveDebt(msg.sender, vars.compositeDebt);

        contractsCache.troveManager.updateTroveRewardSnapshots(msg.sender);
        vars.stake = contractsCache.troveManager.updateStakeAndTotalStakes(msg.sender);

        sortedTroves.insert(msg.sender, vars.NICR, _upperHint, _lowerHint);
        vars.arrayIndex = contractsCache.troveManager.addTroveOwnerToArray(msg.sender);
        emit TroveCreated(msg.sender, vars.arrayIndex);

        // Move the ether to the Active Pool, and mint the RUBCAmount to the borrower
        _activePoolAddColl(contractsCache.activePool, msg.value);
        _withdrawRUBC(contractsCache.activePool, contractsCache.rubc, msg.sender, _RUBCAmount, vars.netDebt);
        // Move the RUBC gas compensation to the Gas Pool
        _withdrawRUBC(contractsCache.activePool, contractsCache.rubc, gasPoolAddress, RUBC_GAS_COMPENSATION, RUBC_GAS_COMPENSATION);

        emit TroveUpdated(msg.sender, vars.compositeDebt, msg.value, vars.stake, BorrowerOperation.openTrove);
        emit RUBCBorrowingFeePaid(msg.sender, vars.RUBCFee);
    }

    // Send ETH as collateral to a trove
    function addColl(address _upperHint, address _lowerHint) external payable override {
        _adjustTrove(msg.sender, 0, 0, false, _upperHint, _lowerHint, 0);
    }

    // Send ETH as collateral to a trove. Called by only the Stability Pool.
    function moveETHGainToTrove(address _borrower, address _upperHint, address _lowerHint) external payable override {
        _requireCallerIsStabilityPool();
        _adjustTrove(_borrower, 0, 0, false, _upperHint, _lowerHint, 0);
    }

    // Withdraw ETH collateral from a trove
    function withdrawColl(uint _collWithdrawal, address _upperHint, address _lowerHint) external override {
        _adjustTrove(msg.sender, _collWithdrawal, 0, false, _upperHint, _lowerHint, 0);
    }

    // Withdraw RUBC tokens from a trove: mint new RUBC tokens to the owner, and increase the trove's debt accordingly
    function withdrawRUBC(uint _maxFeePercentage, uint _RUBCAmount, address _upperHint, address _lowerHint) external override {
        _adjustTrove(msg.sender, 0, _RUBCAmount, true, _upperHint, _lowerHint, _maxFeePercentage);
    }

    // Repay RUBC tokens to a Trove: Burn the repaid RUBC tokens, and reduce the trove's debt accordingly
    function repayRUBC(uint _RUBCAmount, address _upperHint, address _lowerHint) external override {
        _adjustTrove(msg.sender, 0, _RUBCAmount, false, _upperHint, _lowerHint, 0);
    }

    function adjustTrove(uint _maxFeePercentage, uint _collWithdrawal, uint _RUBCChange, bool _isDebtIncrease, address _upperHint, address _lowerHint) external payable override {
        _adjustTrove(msg.sender, _collWithdrawal, _RUBCChange, _isDebtIncrease, _upperHint, _lowerHint, _maxFeePercentage);
    }

    /*
    * _adjustTrove(): Alongside a debt change, this function can perform either a collateral top-up or a collateral withdrawal. 
    *
    * It therefore expects either a positive msg.value, or a positive _collWithdrawal argument.
    *
    * If both are positive, it will revert.
    */
    function _adjustTrove(address _borrower, uint _collWithdrawal, uint _RUBCChange, bool _isDebtIncrease, address _upperHint, address _lowerHint, uint _maxFeePercentage) internal {
        ContractsCache memory contractsCache = ContractsCache(troveManager, activePool, rubc);
        LocalVariables_adjustTrove memory vars;

        vars.price = priceFeed.fetchPrice();
        bool isRecoveryMode = _checkRecoveryMode(vars.price);

        if (_isDebtIncrease) {
            _requireValidMaxFeePercentage(_maxFeePercentage, isRecoveryMode);
            _requireNonZeroDebtChange(_RUBCChange);
        }
        _requireSingularCollChange(_collWithdrawal);
        _requireNonZeroAdjustment(_collWithdrawal, _RUBCChange);
        _requireTroveisActive(contractsCache.troveManager, _borrower);

        // Confirm the operation is either a borrower adjusting their own trove, or a pure ETH transfer from the Stability Pool to a trove
        assert(msg.sender == _borrower || (msg.sender == stabilityPoolAddress && msg.value > 0 && _RUBCChange == 0));

        contractsCache.troveManager.applyPendingRewards(_borrower);

        // Get the collChange based on whether or not ETH was sent in the transaction
        (vars.collChange, vars.isCollIncrease) = _getCollChange(msg.value, _collWithdrawal);

        vars.netDebtChange = _RUBCChange;

        // If the adjustment incorporates a debt increase and system is in Normal Mode, then trigger a borrowing fee
        if (_isDebtIncrease && !isRecoveryMode) { 
            vars.RUBCFee = _triggerBorrowingFee(contractsCache.troveManager, contractsCache.rubc, _RUBCChange, _maxFeePercentage);
            vars.netDebtChange = vars.netDebtChange.add(vars.RUBCFee); // The raw debt change includes the fee
        }

        vars.debt = contractsCache.troveManager.getTroveDebt(_borrower);
        vars.coll = contractsCache.troveManager.getTroveColl(_borrower);
        
        // Get the trove's old ICR before the adjustment, and what its new ICR will be after the adjustment
        vars.oldICR = LiquityMath._computeCR(vars.coll, vars.debt, vars.price);
        vars.newICR = _getNewICRFromTroveChange(vars.coll, vars.debt, vars.collChange, vars.isCollIncrease, vars.netDebtChange, _isDebtIncrease, vars.price);
        assert(_collWithdrawal <= vars.coll); 

        // Check the adjustment satisfies all conditions for the current system mode
        _requireValidAdjustmentInCurrentMode(isRecoveryMode, _collWithdrawal, _isDebtIncrease, vars);
            
        // When the adjustment is a debt repayment, check it's a valid amount and that the caller has enough RUBC
        if (!_isDebtIncrease && _RUBCChange > 0) {
            _requireAtLeastMinNetDebt(_getNetDebt(vars.debt).sub(vars.netDebtChange));
            _requireValidRUBCRepayment(vars.debt, vars.netDebtChange);
            _requireSufficientRUBCBalance(contractsCache.rubc, _borrower, vars.netDebtChange);
        }

        (vars.newColl, vars.newDebt) = _updateTroveFromAdjustment(contractsCache.troveManager, _borrower, vars.collChange, vars.isCollIncrease, vars.netDebtChange, _isDebtIncrease);
        vars.stake = contractsCache.troveManager.updateStakeAndTotalStakes(_borrower);

        // Re-insert trove in to the sorted list
        uint newNICR = _getNewNominalICRFromTroveChange(vars.coll, vars.debt, vars.collChange, vars.isCollIncrease, vars.netDebtChange, _isDebtIncrease);
        sortedTroves.reInsert(_borrower, newNICR, _upperHint, _lowerHint);

        emit TroveUpdated(_borrower, vars.newDebt, vars.newColl, vars.stake, BorrowerOperation.adjustTrove);
        emit RUBCBorrowingFeePaid(msg.sender,  vars.RUBCFee);

        // Use the unmodified _RUBCChange here, as we don't send the fee to the user
        _moveTokensAndETHfromAdjustment(
            contractsCache.activePool,
            contractsCache.rubc,
            msg.sender,
            vars.collChange,
            vars.isCollIncrease,
            _RUBCChange,
            _isDebtIncrease,
            vars.netDebtChange
        );
    }

    function closeTrove() external override {
        ITroveManager troveManagerCached = troveManager;
        IActivePool activePoolCached = activePool;
        IRUBC rubcCached = rubc;

        _requireTroveisActive(troveManagerCached, msg.sender);
        uint price = priceFeed.fetchPrice();
        _requireNotInRecoveryMode(price);

        troveManagerCached.applyPendingRewards(msg.sender);

        uint coll = troveManagerCached.getTroveColl(msg.sender);
        uint debt = troveManagerCached.getTroveDebt(msg.sender);

        _requireSufficientRUBCBalance(rubcCached, msg.sender, debt.sub(RUBC_GAS_COMPENSATION));

        uint newTCR = _getNewTCRFromTroveChange(coll, false, debt, false, price);
        _requireNewTCRisAboveCCR(newTCR);

        troveManagerCached.removeStake(msg.sender);
        troveManagerCached.closeTrove(msg.sender);

        emit TroveUpdated(msg.sender, 0, 0, 0, BorrowerOperation.closeTrove);

        // Burn the repaid RUBC from the user's balance and the gas compensation from the Gas Pool
        _repayRUBC(activePoolCached, rubcCached, msg.sender, debt.sub(RUBC_GAS_COMPENSATION));
        _repayRUBC(activePoolCached, rubcCached, gasPoolAddress, RUBC_GAS_COMPENSATION);

        // Send the collateral back to the user
        activePoolCached.sendETH(msg.sender, coll);
    }

    /**
     * Claim remaining collateral from a redemption or from a liquidation with ICR > MCR in Recovery Mode
     */
    function claimCollateral() external override {
        // send ETH from CollSurplus Pool to owner
        collSurplusPool.claimColl(msg.sender);
    }