0g-chain/x/hard/keeper/borrow.go
2020-12-21 18:18:55 +01:00

301 lines
12 KiB
Go

package keeper
import (
"strings"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
"github.com/kava-labs/kava/x/hard/types"
)
// Borrow funds
func (k Keeper) Borrow(ctx sdk.Context, borrower sdk.AccAddress, coins sdk.Coins) error {
// Set any new denoms' global borrow index to 1.0
for _, coin := range coins {
_, foundInterestFactor := k.GetInterestFactor(ctx, coin.Denom)
if !foundInterestFactor {
_, foundMm := k.GetMoneyMarket(ctx, coin.Denom)
if foundMm {
k.SetInterestFactor(ctx, coin.Denom, sdk.OneDec())
}
}
}
// Get current stored LTV based on stored borrows/deposits
prevLtv, shouldRemoveIndex, err := k.GetStoreLTV(ctx, borrower)
if err != nil {
return err
}
// If the user has an existing borrow, sync its outstanding interest
_, found := k.GetBorrow(ctx, borrower)
if found {
k.SyncOutstandingInterest(ctx, borrower)
}
// Validate borrow amount within user and protocol limits
err = k.ValidateBorrow(ctx, borrower, coins)
if err != nil {
return err
}
// Sends coins from Hard module account to user
err = k.supplyKeeper.SendCoinsFromModuleToAccount(ctx, types.ModuleAccountName, borrower, coins)
if err != nil {
if strings.Contains(err.Error(), "insufficient account funds") {
modAccCoins := k.supplyKeeper.GetModuleAccount(ctx, types.ModuleAccountName).GetCoins()
for _, coin := range coins {
_, isNegative := modAccCoins.SafeSub(sdk.NewCoins(coin))
if isNegative {
return sdkerrors.Wrapf(types.ErrBorrowExceedsAvailableBalance,
"the requested borrow amount of %s exceeds the total amount of %s%s available to borrow",
coin, modAccCoins.AmountOf(coin.Denom), coin.Denom,
)
}
}
}
}
// On user's first borrow, build borrow index list containing denoms and current global borrow index value
// We use a list of BorrowIndexItem here because Amino doesn't support marshaling maps.
if !found {
var interestFactors types.InterestFactors
for _, coin := range coins {
interestFactorValue, _ := k.GetInterestFactor(ctx, coin.Denom)
interestFactor := types.NewInterestFactor(coin.Denom, interestFactorValue)
interestFactors = append(interestFactors, interestFactor)
}
borrow := types.NewBorrow(borrower, sdk.Coins{}, interestFactors)
k.SetBorrow(ctx, borrow)
}
// Add the newly borrowed coins to the user's borrow object
borrow, _ := k.GetBorrow(ctx, borrower)
borrow.Amount = borrow.Amount.Add(coins...)
k.SetBorrow(ctx, borrow)
k.UpdateItemInLtvIndex(ctx, prevLtv, shouldRemoveIndex, borrower)
// Update total borrowed amount by newly borrowed coins. Don't add user's pending interest as
// it has already been included in the total borrowed coins by the BeginBlocker.
k.IncrementBorrowedCoins(ctx, coins)
ctx.EventManager().EmitEvent(
sdk.NewEvent(
types.EventTypeHardBorrow,
sdk.NewAttribute(types.AttributeKeyBorrower, borrower.String()),
sdk.NewAttribute(types.AttributeKeyBorrowCoins, coins.String()),
),
)
return nil
}
// SyncOutstandingInterest updates the user's owed interest on newly borrowed coins to the latest global state
func (k Keeper) SyncOutstandingInterest(ctx sdk.Context, addr sdk.AccAddress) {
totalNewInterest := sdk.Coins{}
// Update user's borrow index list for each asset in the 'coins' array.
// We use a list of BorrowIndexItem here because Amino doesn't support marshaling maps.
borrow, found := k.GetBorrow(ctx, addr)
if !found {
return
}
for _, coin := range borrow.Amount {
// Locate the borrow index item by coin denom in the user's list of borrow indexes
foundAtIndex := -1
for i := range borrow.Index {
if borrow.Index[i].Denom == coin.Denom {
foundAtIndex = i
break
}
}
interestFactorValue, _ := k.GetInterestFactor(ctx, coin.Denom)
if foundAtIndex == -1 { // First time user has borrowed this denom
borrow.Index = append(borrow.Index, types.NewInterestFactor(coin.Denom, interestFactorValue))
} else { // User has an existing borrow index for this denom
// Calculate interest owed by user since asset's last borrow index update
storedAmount := sdk.NewDecFromInt(borrow.Amount.AmountOf(coin.Denom))
userLastInterestFactor := borrow.Index[foundAtIndex].Value
interest := (storedAmount.Quo(userLastInterestFactor).Mul(interestFactorValue)).Sub(storedAmount)
totalNewInterest = totalNewInterest.Add(sdk.NewCoin(coin.Denom, interest.TruncateInt()))
// We're synced up, so update user's borrow index value to match the current global borrow index value
borrow.Index[foundAtIndex].Value = interestFactorValue
}
}
// Add all pending interest to user's borrow
borrow.Amount = borrow.Amount.Add(totalNewInterest...)
// Update user's borrow in the store
k.SetBorrow(ctx, borrow)
}
// ValidateBorrow validates a borrow request against borrower and protocol requirements
func (k Keeper) ValidateBorrow(ctx sdk.Context, borrower sdk.AccAddress, amount sdk.Coins) error {
if amount.IsZero() {
return types.ErrBorrowEmptyCoins
}
// Get the proposed borrow USD value
moneyMarketCache := map[string]types.MoneyMarket{}
proprosedBorrowUSDValue := sdk.ZeroDec()
for _, coin := range amount {
moneyMarket, ok := moneyMarketCache[coin.Denom]
// Fetch money market and store in local cache
if !ok {
newMoneyMarket, found := k.GetMoneyMarketParam(ctx, coin.Denom)
if !found {
return sdkerrors.Wrapf(types.ErrMarketNotFound, "no market found for denom %s", coin.Denom)
}
moneyMarketCache[coin.Denom] = newMoneyMarket
moneyMarket = newMoneyMarket
}
// Calculate this coin's USD value and add it borrow's total USD value
assetPriceInfo, err := k.pricefeedKeeper.GetCurrentPrice(ctx, moneyMarket.SpotMarketID)
if err != nil {
return sdkerrors.Wrapf(types.ErrPriceNotFound, "no price found for market %s", moneyMarket.SpotMarketID)
}
coinUSDValue := sdk.NewDecFromInt(coin.Amount).Quo(sdk.NewDecFromInt(moneyMarket.ConversionFactor)).Mul(assetPriceInfo.Price)
// Validate the requested borrow value for the asset against the money market's global borrow limit
if moneyMarket.BorrowLimit.HasMaxLimit {
var assetTotalBorrowedAmount sdk.Int
totalBorrowedCoins, found := k.GetBorrowedCoins(ctx)
if !found {
assetTotalBorrowedAmount = sdk.ZeroInt()
} else {
assetTotalBorrowedAmount = totalBorrowedCoins.AmountOf(coin.Denom)
}
newProposedAssetTotalBorrowedAmount := sdk.NewDecFromInt(assetTotalBorrowedAmount.Add(coin.Amount))
if newProposedAssetTotalBorrowedAmount.GT(moneyMarket.BorrowLimit.MaximumLimit) {
return sdkerrors.Wrapf(types.ErrGreaterThanAssetBorrowLimit,
"proposed borrow would result in %s borrowed, but the maximum global asset borrow limit is %s",
newProposedAssetTotalBorrowedAmount, moneyMarket.BorrowLimit.MaximumLimit)
}
}
proprosedBorrowUSDValue = proprosedBorrowUSDValue.Add(coinUSDValue)
}
// Get the total borrowable USD amount at user's existing deposits
deposit, found := k.GetDeposit(ctx, borrower)
if !found {
return sdkerrors.Wrapf(types.ErrDepositsNotFound, "no deposits found for %s", borrower)
}
totalBorrowableAmount := sdk.ZeroDec()
for _, depCoin := range deposit.Amount {
moneyMarket, ok := moneyMarketCache[depCoin.Denom]
// Fetch money market and store in local cache
if !ok {
newMoneyMarket, found := k.GetMoneyMarketParam(ctx, depCoin.Denom)
if !found {
return sdkerrors.Wrapf(types.ErrMarketNotFound, "no market found for denom %s", depCoin.Denom)
}
moneyMarketCache[depCoin.Denom] = newMoneyMarket
moneyMarket = newMoneyMarket
}
// Calculate the borrowable amount and add it to the user's total borrowable amount
assetPriceInfo, err := k.pricefeedKeeper.GetCurrentPrice(ctx, moneyMarket.SpotMarketID)
if err != nil {
sdkerrors.Wrapf(types.ErrPriceNotFound, "no price found for market %s", moneyMarket.SpotMarketID)
}
depositUSDValue := sdk.NewDecFromInt(depCoin.Amount).Quo(sdk.NewDecFromInt(moneyMarket.ConversionFactor)).Mul(assetPriceInfo.Price)
borrowableAmountForDeposit := depositUSDValue.Mul(moneyMarket.BorrowLimit.LoanToValue)
totalBorrowableAmount = totalBorrowableAmount.Add(borrowableAmountForDeposit)
}
// Get the total USD value of user's existing borrows
existingBorrowUSDValue := sdk.ZeroDec()
existingBorrow, found := k.GetBorrow(ctx, borrower)
if found {
for _, borrowedCoin := range existingBorrow.Amount {
moneyMarket, ok := moneyMarketCache[borrowedCoin.Denom]
// Fetch money market and store in local cache
if !ok {
newMoneyMarket, found := k.GetMoneyMarketParam(ctx, borrowedCoin.Denom)
if !found {
return sdkerrors.Wrapf(types.ErrMarketNotFound, "no market found for denom %s", borrowedCoin.Denom)
}
moneyMarketCache[borrowedCoin.Denom] = newMoneyMarket
moneyMarket = newMoneyMarket
}
// Calculate this borrow coin's USD value and add it to the total previous borrowed USD value
assetPriceInfo, err := k.pricefeedKeeper.GetCurrentPrice(ctx, moneyMarket.SpotMarketID)
if err != nil {
return sdkerrors.Wrapf(types.ErrPriceNotFound, "no price found for market %s", moneyMarket.SpotMarketID)
}
coinUSDValue := sdk.NewDecFromInt(borrowedCoin.Amount).Quo(sdk.NewDecFromInt(moneyMarket.ConversionFactor)).Mul(assetPriceInfo.Price)
existingBorrowUSDValue = existingBorrowUSDValue.Add(coinUSDValue)
}
}
// Validate that the proposed borrow's USD value is within user's borrowable limit
if proprosedBorrowUSDValue.GT(totalBorrowableAmount.Sub(existingBorrowUSDValue)) {
return sdkerrors.Wrapf(types.ErrInsufficientLoanToValue, "requested borrow %s exceeds the allowable amount as determined by the collateralization ratio", amount)
}
return nil
}
// IncrementBorrowedCoins increments the amount of borrowed coins by the newCoins parameter
func (k Keeper) IncrementBorrowedCoins(ctx sdk.Context, newCoins sdk.Coins) {
borrowedCoins, found := k.GetBorrowedCoins(ctx)
if !found {
if !newCoins.Empty() {
k.SetBorrowedCoins(ctx, newCoins)
}
} else {
k.SetBorrowedCoins(ctx, borrowedCoins.Add(newCoins...))
}
}
// DecrementBorrowedCoins decrements the amount of borrowed coins by the coins parameter
func (k Keeper) DecrementBorrowedCoins(ctx sdk.Context, coins sdk.Coins) error {
borrowedCoins, found := k.GetBorrowedCoins(ctx)
if !found {
return sdkerrors.Wrapf(types.ErrBorrowedCoinsNotFound, "cannot repay coins if no coins are currently borrowed")
}
updatedBorrowedCoins, isAnyNegative := borrowedCoins.SafeSub(coins)
if isAnyNegative {
return types.ErrNegativeBorrowedCoins
}
k.SetBorrowedCoins(ctx, updatedBorrowedCoins)
return nil
}
// GetBorrowBalance gets the user's total borrow balance (borrow balance + pending interest)
func (k Keeper) GetBorrowBalance(ctx sdk.Context, borrower sdk.AccAddress) sdk.Coins {
borrowBalance := sdk.Coins{}
borrow, found := k.GetBorrow(ctx, borrower)
if found {
totalNewInterest := sdk.Coins{}
for _, coin := range borrow.Amount {
interestFactorValue, foundInterestFactorValue := k.GetInterestFactor(ctx, coin.Denom)
if foundInterestFactorValue {
// Locate the interest factor by coin denom in the user's list of interest factors
foundAtIndex := -1
for i := range borrow.Index {
if borrow.Index[i].Denom == coin.Denom {
foundAtIndex = i
break
}
}
// Calculate interest owed by user for this asset
if foundAtIndex != -1 {
storedAmount := sdk.NewDecFromInt(borrow.Amount.AmountOf(coin.Denom))
userLastInterestFactor := borrow.Index[foundAtIndex].Value
coinInterest := (storedAmount.Quo(userLastInterestFactor).Mul(interestFactorValue)).Sub(storedAmount)
totalNewInterest = totalNewInterest.Add(sdk.NewCoin(coin.Denom, coinInterest.TruncateInt()))
}
}
}
borrowBalance = borrow.Amount.Add(totalNewInterest...)
}
return borrowBalance
}