query borrow balance (#732)

x/harvest/client/cli/query.go

@@ -41,6 +41,7 @@ func GetQueryCmd(queryRoute string, cdc *codec.Codec) *cobra.Command {
 		queryDepositsCmd(queryRoute, cdc),
 		queryClaimsCmd(queryRoute, cdc),
 		queryBorrowsCmd(queryRoute, cdc),
+		queryBorrowCmd(queryRoute, cdc),
 	)...)
 
 	return harvestQueryCmd
@@ -325,3 +326,50 @@ func queryBorrowedCmd(queryRoute string, cdc *codec.Codec) *cobra.Command {
 		},
 	}
 }
+
+func queryBorrowCmd(queryRoute string, cdc *codec.Codec) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "borrow",
+		Short: "query outstanding borrow balance for a user",
+		Long: strings.TrimSpace(`query outstanding borrow balance for a user:
+		Example:
+		$ kvcli q harvest borrow --owner kava1l0xsq2z7gqd7yly0g40y5836g0appumark77ny`,
+		),
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			cliCtx := context.NewCLIContext().WithCodec(cdc)
+
+			var owner sdk.AccAddress
+
+			ownerBech := viper.GetString(flagOwner)
+			if len(ownerBech) != 0 {
+				borrowOwner, err := sdk.AccAddressFromBech32(ownerBech)
+				if err != nil {
+					return err
+				}
+				owner = borrowOwner
+			}
+
+			params := types.NewQueryBorrow(owner)
+			bz, err := cdc.MarshalJSON(params)
+			if err != nil {
+				return err
+			}
+
+			route := fmt.Sprintf("custom/%s/%s", queryRoute, types.QueryGetBorrow)
+			res, height, err := cliCtx.QueryWithData(route, bz)
+			if err != nil {
+				return err
+			}
+			cliCtx = cliCtx.WithHeight(height)
+
+			var balance sdk.Coins
+			if err := cdc.UnmarshalJSON(res, &balance); err != nil {
+				return fmt.Errorf("failed to unmarshal borrow balance: %w", err)
+			}
+			return cliCtx.PrintOutput(balance)
+		},
+	}
+	cmd.Flags().String(flagOwner, "", "filter for borrows by owner address")
+	return cmd
+}

x/harvest/keeper/borrow.go

@@ -254,3 +254,34 @@ func (k Keeper) DecrementBorrowedCoins(ctx sdk.Context, coins sdk.Coins) error {
 	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 {
+			borrowIndexValue, foundBorrowIndexValue := k.GetBorrowIndex(ctx, coin.Denom)
+			if foundBorrowIndexValue {
+				// 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
+					}
+				}
+				// Calculate interest owed by user for this asset
+				if foundAtIndex != -1 {
+					storedAmount := sdk.NewDecFromInt(borrow.Amount.AmountOf(coin.Denom))
+					userLastBorrowIndex := borrow.Index[foundAtIndex].Value
+					coinInterest := (storedAmount.Quo(userLastBorrowIndex).Mul(borrowIndexValue)).Sub(storedAmount)
+					totalNewInterest = totalNewInterest.Add(sdk.NewCoin(coin.Denom, coinInterest.TruncateInt()))
+				}
+			}
+		}
+		borrowBalance = borrow.Amount.Add(totalNewInterest...)
+	}
+	return borrowBalance
+}

x/harvest/keeper/querier.go

@@ -26,6 +26,8 @@ func NewQuerier(k Keeper) sdk.Querier {
 			return queryGetClaims(ctx, req, k)
 		case types.QueryGetBorrows:
 			return queryGetBorrows(ctx, req, k)
+		case types.QueryGetBorrow:
+			return queryGetBorrow(ctx, req, k)
 		case types.QueryGetBorrowed:
 			return queryGetBorrowed(ctx, req, k)
 		default:
@@ -289,3 +291,23 @@ func queryGetBorrowed(ctx sdk.Context, req abci.RequestQuery, k Keeper) ([]byte,
 
 	return bz, nil
 }
+
+func queryGetBorrow(ctx sdk.Context, req abci.RequestQuery, k Keeper) ([]byte, error) {
+	var params types.QueryBorrowParams
+	err := types.ModuleCdc.UnmarshalJSON(req.Data, &params)
+	if err != nil {
+		return nil, sdkerrors.Wrap(sdkerrors.ErrJSONUnmarshal, err.Error())
+	}
+
+	var borrowBalance sdk.Coins
+	if len(params.Owner) > 0 {
+		borrowBalance = k.GetBorrowBalance(ctx, params.Owner)
+	}
+
+	bz, err := codec.MarshalJSONIndent(types.ModuleCdc, borrowBalance)
+	if err != nil {
+		return nil, sdkerrors.Wrap(sdkerrors.ErrJSONMarshal, err.Error())
+	}
+
+	return bz, nil
+}

x/harvest/types/querier.go

@@ -12,6 +12,7 @@ const (
 	QueryGetClaims         = "claims"
 	QueryGetBorrows        = "borrows"
 	QueryGetBorrowed       = "borrowed"
+	QueryGetBorrow         = "borrow"
 )
 
 // QueryDepositParams is the params for a filtered deposit query
@@ -97,3 +98,15 @@ func NewQueryBorrowedParams(denom string) QueryBorrowedParams {
 		Denom: denom,
 	}
 }
+
+// QueryBorrow is the params for a current borrow balance query
+type QueryBorrow struct {
+	Owner sdk.AccAddress `json:"owner" yaml:"owner"`
+}
+
+// NewQueryBorrow creates a new QueryBorrow
+func NewQueryBorrow(owner sdk.AccAddress) QueryBorrow {
+	return QueryBorrow{
+		Owner: owner,
+	}
+}