package keeper import ( "time" "github.com/cosmos/cosmos-sdk/store/prefix" sdk "github.com/cosmos/cosmos-sdk/types" sdkerrors "github.com/cosmos/cosmos-sdk/types/errors" authexported "github.com/cosmos/cosmos-sdk/x/auth/exported" supplyexported "github.com/cosmos/cosmos-sdk/x/supply/exported" "github.com/kava-labs/kava/x/cdp/types" ) // DistributeSavingsRate distributes surplus that has accumulated in the liquidator account to address holding stable coins according the the savings rate func (k Keeper) DistributeSavingsRate(ctx sdk.Context, debtDenom string) error { dp, found := k.GetDebtParam(ctx, debtDenom) if !found { return sdkerrors.Wrap(types.ErrDebtNotSupported, debtDenom) } savingsRateMacc := k.supplyKeeper.GetModuleAccount(ctx, types.SavingsRateMacc) surplusToDistribute := savingsRateMacc.GetCoins().AmountOf(dp.Denom) if surplusToDistribute.IsZero() { return nil } modAccountCoins := k.getModuleAccountCoins(ctx, dp.Denom) totalSupplyLessModAccounts := k.supplyKeeper.GetSupply(ctx).GetTotal().Sub(modAccountCoins) surplusDistributed := sdk.ZeroInt() var iterationErr error k.accountKeeper.IterateAccounts(ctx, func(acc authexported.Account) (stop bool) { _, ok := acc.(supplyexported.ModuleAccountI) if ok { // don't distribute savings rate to module accounts return false } debtAmount := acc.GetCoins().AmountOf(debtDenom) if !debtAmount.IsPositive() { return false } // (balance * rewardToDisribute) / totalSupply // interest is the ratable fraction of savings rate owed to that account, rounded using bankers rounding interest := (sdk.NewDecFromInt(debtAmount).Mul(sdk.NewDecFromInt(surplusToDistribute))).Quo(sdk.NewDecFromInt(totalSupplyLessModAccounts.AmountOf(debtDenom))).RoundInt() // sanity check, if we are going to over-distribute due to rounding, distribute only the remaining savings rate that hasn't been distributed. if interest.GT(surplusToDistribute.Sub(surplusDistributed)) { interest = surplusToDistribute.Sub(surplusDistributed) } // sanity check - don't send saving rate if the rounded amount is zero if !interest.IsPositive() { return false } interestCoins := sdk.NewCoins(sdk.NewCoin(debtDenom, interest)) err := k.supplyKeeper.SendCoinsFromModuleToAccount(ctx, types.SavingsRateMacc, acc.GetAddress(), interestCoins) if err != nil { iterationErr = err return true } surplusDistributed = surplusDistributed.Add(interest) return false }) return iterationErr } // GetPreviousSavingsDistribution get the time of the previous savings rate distribution func (k Keeper) GetPreviousSavingsDistribution(ctx sdk.Context) (distTime time.Time, found bool) { store := prefix.NewStore(ctx.KVStore(k.key), types.PreviousDistributionTimeKey) b := store.Get([]byte{}) if b == nil { return time.Time{}, false } k.cdc.MustUnmarshalBinaryLengthPrefixed(b, &distTime) return distTime, true } // SetPreviousSavingsDistribution set the time of the previous block func (k Keeper) SetPreviousSavingsDistribution(ctx sdk.Context, distTime time.Time) { store := prefix.NewStore(ctx.KVStore(k.key), types.PreviousDistributionTimeKey) store.Set([]byte{}, k.cdc.MustMarshalBinaryLengthPrefixed(distTime)) } // getModuleAccountCoins gets the total coin balance of this coin currently held by module accounts func (k Keeper) getModuleAccountCoins(ctx sdk.Context, denom string) sdk.Coins { totalModCoinBalance := sdk.NewCoins(sdk.NewCoin(denom, sdk.ZeroInt())) for macc := range k.maccPerms { modCoinBalance := k.supplyKeeper.GetModuleAccount(ctx, macc).GetCoins().AmountOf(denom) if modCoinBalance.IsPositive() { totalModCoinBalance = totalModCoinBalance.Add(sdk.NewCoin(denom, modCoinBalance)) } } return totalModCoinBalance }