0g-chain/x/hard/keeper/repay.go
Denali Marsh bc110ce609
Hard: LTV index refactor (#758)
* add set/delete/update ltv methods

* refactor borrow logic

* basic updates to keeper logic for compile

* Add deposit index set/delete/update keeper methods

* refactor deposit logic

* refactor repay logic

* update withdraw logic

* introduce DeleteDepositBorrowAndLtvIndex

* remove unused bool from AttemptKeeperLiquidation

* remove comments (transitioned to asana cards)

* catch multiple error types in liquidation loop
2021-01-07 22:40:25 +01:00

104 lines
2.7 KiB
Go

package keeper
import (
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
"github.com/kava-labs/kava/x/hard/types"
)
// Repay borrowed funds
func (k Keeper) Repay(ctx sdk.Context, sender sdk.AccAddress, coins sdk.Coins) error {
// Get current stored LTV based on stored borrows/deposits
prevLtv, err := k.GetStoreLTV(ctx, sender)
if err != nil {
return err
}
// Sync borrow interest so loan is up-to-date
k.SyncBorrowInterest(ctx, sender)
// Validate requested repay
err = k.ValidateRepay(ctx, sender, coins)
if err != nil {
return err
}
// Check borrow exists here to avoid duplicating store read in ValidateRepay
borrow, found := k.GetBorrow(ctx, sender)
if !found {
return types.ErrBorrowNotFound
}
payment, err := k.CalculatePaymentAmount(borrow.Amount, coins)
if err != nil {
return err
}
// Sends coins from user to Hard module account
err = k.supplyKeeper.SendCoinsFromAccountToModule(ctx, sender, types.ModuleAccountName, payment)
if err != nil {
return err
}
// Update user's borrow in store
borrow.Amount = borrow.Amount.Sub(payment)
// Calculate the new Loan-to-Value ratio of Deposit-to-Borrow
deposit, foundDeposit := k.GetDeposit(ctx, sender)
if !foundDeposit {
return types.ErrDepositNotFound
}
newLtv, err := k.CalculateLtv(ctx, deposit, borrow)
if err != nil {
return err
}
k.UpdateBorrowAndLtvIndex(ctx, borrow, newLtv, prevLtv)
// Update total borrowed amount
k.DecrementBorrowedCoins(ctx, payment)
ctx.EventManager().EmitEvent(
sdk.NewEvent(
types.EventTypeHardRepay,
sdk.NewAttribute(types.AttributeKeySender, sender.String()),
sdk.NewAttribute(types.AttributeKeyRepayCoins, payment.String()),
),
)
return nil
}
// ValidateRepay validates a requested loan repay
func (k Keeper) ValidateRepay(ctx sdk.Context, sender sdk.AccAddress, coins sdk.Coins) error {
senderAcc := k.accountKeeper.GetAccount(ctx, sender)
senderCoins := senderAcc.SpendableCoins(ctx.BlockTime())
for _, coin := range coins {
if senderCoins.AmountOf(coin.Denom).LT(coin.Amount) {
return sdkerrors.Wrapf(types.ErrInsufficientBalanceForRepay, "account can only repay up to %s%s", senderCoins.AmountOf(coin.Denom), coin.Denom)
}
}
return nil
}
// CalculatePaymentAmount prevents overpayment when repaying borrowed coins
func (k Keeper) CalculatePaymentAmount(owed sdk.Coins, payment sdk.Coins) (sdk.Coins, error) {
repayment := sdk.Coins{}
if !payment.DenomsSubsetOf(owed) {
return repayment, types.ErrInvalidRepaymentDenom
}
for _, coin := range payment {
if coin.Amount.GT(owed.AmountOf(coin.Denom)) {
repayment = append(repayment, sdk.NewCoin(coin.Denom, owed.AmountOf(coin.Denom)))
} else {
repayment = append(repayment, coin)
}
}
return repayment, nil
}