# DInterestLens ## `withdrawableAmountOfDeposit(contract DInterest pool, uint64 depositID, uint256 virtualTokenAmount) → uint256 withdrawableAmount, uint256 feeAmount` (external) Computes the amount of stablecoins that can be withdrawn by burning `virtualTokenAmount` virtual tokens from the deposit with ID `depositID` at time `timestamp`. @dev The queried timestamp should >= the deposit's lastTopupTimestamp, since the information before this time is forgotten. @param pool The DInterest pool @param depositID The ID of the deposit @param virtualTokenAmount The amount of virtual tokens to burn @return withdrawableAmount The amount of stablecoins (after fee) that can be withdrawn @return feeAmount The amount of fees that will be given to the beneficiary ## `accruedInterestOfFunding(contract DInterest pool, uint64 fundingID) → uint256 fundingInterestAmount` (external) Computes the floating-rate interest accrued in the floating-rate bond with ID `fundingID`. @param pool The DInterest pool @param fundingID The ID of the floating-rate bond @return fundingInterestAmount The interest accrued, in stablecoins ## `fundingIsActive(contract DInterest pool, uint64 fundingID) → bool` (external) A floating-rate bond is no longer active if its principalPerToken becomes 0, which occurs when the corresponding deposit is completely withdrawn. When such a deposit is topped up, a new Funding struct and floating-rate bond will be created. @param pool The DInterest pool @param fundingID The ID of the floating-rate bond @return True if the funding is active, false otherwise ## `totalInterestOwedToFunders(contract DInterest pool) → uint256 interestOwed` (public) Computes the floating interest amount owed to deficit funders, which will be paid out when a funded deposit is withdrawn. Formula:∑irecordedFundedPrincipalAmounti(incomeIndexrecordedMoneyMarketIncomeIndexi−1)=incomeIndex(∑irecordedFundedPrincipalAmountirecordedMoneyMarketIncomeIndexi)−∑irecordedFundedPrincipalAmounti\sum\_i recordedFundedPrincipalAmount\_i (\frac{incomeIndex}{recordedMoneyMarketIncomeIndex\_i} - 1) = incomeIndex (\sum\_i \frac{recordedFundedPrincipalAmount\_i}{recordedMoneyMarketIncomeIndex\_i}) - \sum\_i recordedFundedPrincipalAmount\_i∑i​recordedFundedPrincipalAmounti​(recordedMoneyMarketIncomeIndexi​incomeIndex​−1)=incomeIndex(∑i​recordedMoneyMarketIncomeIndexi​recordedFundedPrincipalAmounti​​)−∑i​recordedFundedPrincipalAmounti​​ where i refers to a funding @param pool The DInterest pool @return interestOwed The floating-rate interest accrued to all floating-rate bond holders ## `surplusOfDeposit(contract DInterest pool, uint64 depositID) → bool isNegative, uint256 surplusAmount` (public) Computes the surplus of a deposit, which is the raw surplus of the unfunded part of the deposit. If the deposit is not funded, this will return the same value as {rawSurplusOfDeposit}. @param depositID The ID of the deposit @return isNegative True if the surplus is negative, false otherwise @return surplusAmount The absolute value of the surplus, in stablecoins ## `_depositVirtualTokenToPrincipal(struct DInterest.Deposit depositEntry, uint256 virtualTokenAmount) → uint256` (internal) Converts a virtual token value into the corresponding principal value. Principal refers to deposit + full interest + fee. @param depositEntry The deposit struct @param virtualTokenAmount The virtual token value @return The corresponding principal value ## `rawSurplusOfDeposit(uint64 depositID) → bool isNegative, uint256 surplusAmount` (public) Computes the raw surplus of a deposit, which is the current value of the deposit in the money market minus the amount owed (deposit + interest + fee). The deposit's funding status is not considered here, meaning even if a deposit's fixed-rate interest is fully funded, it likely will still have a non-zero surplus. @param depositID The ID of the deposit @return isNegative True if the surplus is negative, false otherwise @return surplusAmount The absolute value of the surplus, in stablecoins