0g-chain/x/hard/keeper/repay.go
Denali Marsh f7a73c9245
Hard: suppliers earn interest (#749)
* update to borrow interest factor

* add supply interest factor to accrue interest

* supply interest factor keeper methods

* fix potential bug with user borrow indexing

* sync supply interest on deposit/withdraw

* separate withdraw/deposit

* relocate interest sync methods

* update comment

* simplify supply interest statement

* check truncated int not zero

* add .sub(storedAmount) back

* add store key suppliedcoins

* increment/decrement supplied coins

* update withdraw with new accounting

* update withdraw test

* catch repay edge case

* unit tests

* TestSupplyInterest scaffolding

* test notes

* temp: interest test

* example test

* changes, test checks more state

* fix: calculate supply interest directly

* fix: catch divide by zero

* add state checks back into interest test

* add snapshot test cases

* test owed supplied interest paid at correct ratio

* test user supply syncs user's borrow interest

* remove print statements and clean up

* refactor indented logic

* test supply/borrow multiple coins

* update decoder test

Co-authored-by: karzak <kjydavis3@gmail.com>
2021-01-07 11:23:05 +01:00

95 lines
2.5 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, shouldRemoveIndex, 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)
k.SetBorrow(ctx, borrow)
k.UpdateItemInLtvIndex(ctx, prevLtv, shouldRemoveIndex, sender)
// 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
}