0g-chain/x/harvest/keeper/repay.go
Denali Marsh 4e641c5212
Hard: repay borrowed coins (#725)
* add msg borrow test

* repay types

* register msg repay on codec

* repay keeper functionality

* repay cli

* repay keeper test

* Hard: repay insufficient balance error (#726)

* repay error: insufficient balance

* isolate coin type in error msg

* add multi-coin repay example

* CalculatePaymentAmount, repay > SyncBorrowInterest

* remove todo: index updated by sync

* update tests

* add back in test
2020-12-07 22:51:35 +01:00

78 lines
2.2 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/harvest/types"
)
// Repay borrowed funds
func (k Keeper) Repay(ctx sdk.Context, sender sdk.AccAddress, coins sdk.Coins) error {
// Sync interest so loan is up-to-date
k.SyncBorrowInterest(ctx, sender, coins)
// 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 := k.CalculatePaymentAmount(borrow.Amount, coins)
// Sends coins from user to Harvest 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)
// Update total borrowed amount
k.DecrementBorrowedCoins(ctx, payment)
ctx.EventManager().EmitEvent(
sdk.NewEvent(
types.EventTypeHarvestRepay,
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.GetCoins()
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 {
repayment := sdk.Coins{}
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
}