Minor asset loop out fixes

assets/client.go

@@ -16,6 +16,7 @@ import (
 	"github.com/lightninglabs/taproot-assets/taprpc/tapchannelrpc"
 	"github.com/lightninglabs/taproot-assets/taprpc/universerpc"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/macaroons"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
@@ -105,9 +106,12 @@ func (c *TapdClient) GetRfqForAsset(ctx context.Context,
 	expiry int64, feeLimitMultiplier float64) (
 	*rfqrpc.PeerAcceptedSellQuote, error) {
 
-	feeLimit, err := lnrpc.UnmarshallAmt(
-		int64(satAmount)+int64(satAmount.MulF64(feeLimitMultiplier)), 0,
-	)
+	// paymentMaxAmt is the maximum amount we are willing to pay for the
+	// payment.
+	// E.g. on a 250k sats payment we'll multiply the sat amount by 1.2.
+	// The resulting maximum amount we're willing to pay is 300k sats.
+	// The response asset amount will be for those 300k sats.
+	paymentMaxAmt, err := getPaymentMaxAmount(satAmount, feeLimitMultiplier)
 	if err != nil {
 		return nil, err
 	}
@@ -120,7 +124,7 @@ func (c *TapdClient) GetRfqForAsset(ctx context.Context,
 				},
 			},
 			PeerPubKey:     peerPubkey,
-			PaymentMaxAmt:  uint64(feeLimit),
+			PaymentMaxAmt:  uint64(paymentMaxAmt),
 			Expiry:         uint64(expiry),
 			TimeoutSeconds: uint32(c.cfg.RFQtimeout.Seconds()),
 		})
@@ -180,6 +184,28 @@ func (c *TapdClient) GetAssetName(ctx context.Context,
 	return assetName, nil
 }
 
+// getPaymentMaxAmount returns the milisat amount we are willing to pay for the
+// payment.
+func getPaymentMaxAmount(satAmount btcutil.Amount, feeLimitMultiplier float64) (
+	lnwire.MilliSatoshi, error) {
+
+	if satAmount == 0 {
+		return 0, fmt.Errorf("satAmount cannot be zero")
+	}
+	if feeLimitMultiplier < 1 {
+		return 0, fmt.Errorf("feeLimitMultiplier must be at least 1")
+	}
+
+	// paymentMaxAmt is the maximum amount we are willing to pay for the
+	// payment.
+	// E.g. on a 250k sats payment we'll multiply the sat amount by 1.2.
+	// The resulting maximum amount we're willing to pay is 300k sats.
+	// The response asset amount will be for those 300k sats.
+	return lnrpc.UnmarshallAmt(
+		int64(satAmount.MulF64(feeLimitMultiplier)), 0,
+	)
+}
+
 func getClientConn(config *TapdConfig) (*grpc.ClientConn, error) {
 	// Load the specified TLS certificate and build transport credentials.
 	creds, err := credentials.NewClientTLSFromFile(config.TLSPath, "")

assets/client_test.go

@@ -0,0 +1,67 @@
+package assets
+
+import (
+	"testing"
+
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/lightningnetwork/lnd/lnwire"
+)
+
+func TestGetPaymentMaxAmount(t *testing.T) {
+	tests := []struct {
+		satAmount          btcutil.Amount
+		feeLimitMultiplier float64
+		expectedAmount     lnwire.MilliSatoshi
+		expectError        bool
+	}{
+		{
+			satAmount:          btcutil.Amount(250000),
+			feeLimitMultiplier: 1.2,
+			expectedAmount:     lnwire.MilliSatoshi(300000000),
+			expectError:        false,
+		},
+		{
+			satAmount:          btcutil.Amount(100000),
+			feeLimitMultiplier: 1.5,
+			expectedAmount:     lnwire.MilliSatoshi(150000000),
+			expectError:        false,
+		},
+		{
+			satAmount:          btcutil.Amount(50000),
+			feeLimitMultiplier: 2.0,
+			expectedAmount:     lnwire.MilliSatoshi(100000000),
+			expectError:        false,
+		},
+		{
+			satAmount:          btcutil.Amount(0),
+			feeLimitMultiplier: 1.2,
+			expectedAmount:     lnwire.MilliSatoshi(0),
+			expectError:        true,
+		},
+		{
+			satAmount:          btcutil.Amount(250000),
+			feeLimitMultiplier: 0.8,
+			expectedAmount:     lnwire.MilliSatoshi(0),
+			expectError:        true,
+		},
+	}
+
+	for _, test := range tests {
+		result, err := getPaymentMaxAmount(
+			test.satAmount, test.feeLimitMultiplier,
+		)
+		if test.expectError {
+			if err == nil {
+				t.Fatalf("expected error but got none")
+			}
+		} else {
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if result != test.expectedAmount {
+				t.Fatalf("expected %v, got %v",
+					test.expectedAmount, result)
+			}
+		}
+	}
+}

client.go

@@ -20,6 +20,7 @@ import (
 	"github.com/lightninglabs/loop/sweep"
 	"github.com/lightninglabs/loop/sweepbatcher"
 	"github.com/lightninglabs/loop/utils"
+	"github.com/lightninglabs/taproot-assets/taprpc/rfqrpc"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"google.golang.org/grpc"
@@ -661,54 +662,12 @@ func (s *Client) LoopOutQuote(ctx context.Context,
 	// If we use an Asset we'll rfq to get the asset amounts to use for
 	// the swap.
 	if request.AssetRFQRequest != nil {
-		rfqReq := request.AssetRFQRequest
-		if rfqReq.Expiry == 0 {
-			rfqReq.Expiry = time.Now().Add(defaultRFQExpiry).Unix()
-		}
-
-		if rfqReq.MaxLimitMultiplier == 0 {
-			rfqReq.MaxLimitMultiplier = defaultRFQMaxLimitMultiplier
-		}
-
-		// First we'll get the prepay rfq.
-		prepayRfq, err := s.assetClient.GetRfqForAsset(
-			ctx, quote.PrepayAmount, rfqReq.AssetId,
-			rfqReq.AssetEdgeNode, rfqReq.Expiry,
-			rfqReq.MaxLimitMultiplier,
-		)
-		if err != nil {
-			return nil, err
-		}
-
-		// The actual invoice swap amount is the requested amount plus
-		// the swap fee minus the prepay amount.
-		invoiceAmt := request.Amount + quote.SwapFee -
-			quote.PrepayAmount
-
-		swapRfq, err := s.assetClient.GetRfqForAsset(
-			ctx, invoiceAmt, rfqReq.AssetId,
-			rfqReq.AssetEdgeNode, rfqReq.Expiry,
-			rfqReq.MaxLimitMultiplier,
-		)
+		rfq, err := s.getAssetRfq(ctx, loopOutQuote, request)
 		if err != nil {
 			return nil, err
 		}
 
-		// We'll also want the asset name to verify for the client.
-		assetName, err := s.assetClient.GetAssetName(
-			ctx, rfqReq.AssetId,
-		)
-		if err != nil {
-			return nil, err
-		}
-
-		loopOutQuote.LoopOutRfq = &LoopOutRfq{
-			PrepayRfqId:    prepayRfq.Id,
-			PrepayAssetAmt: prepayRfq.AssetAmount,
-			SwapRfqId:      swapRfq.Id,
-			SwapAssetAmt:   swapRfq.AssetAmount,
-			AssetName:      assetName,
-		}
+		loopOutQuote.LoopOutRfq = rfq
 	}
 
 	return loopOutQuote, nil
@@ -1000,3 +959,77 @@ func (s *Client) AbandonSwap(ctx context.Context,
 
 	return nil
 }
+
+// getAssetRfq returns a prepay and swap rfq for the asset swap.
+func (s *Client) getAssetRfq(ctx context.Context, quote *LoopOutQuote,
+	request *LoopOutQuoteRequest) (*LoopOutRfq, error) {
+
+	if s.assetClient == nil {
+		return nil, errors.New("asset client must be set " +
+			"when trying to loop out with an asset")
+	}
+	rfqReq := request.AssetRFQRequest
+	if rfqReq.Expiry == 0 {
+		rfqReq.Expiry = time.Now().Add(defaultRFQExpiry).Unix()
+	}
+
+	if rfqReq.MaxLimitMultiplier == 0 {
+		rfqReq.MaxLimitMultiplier = defaultRFQMaxLimitMultiplier
+	}
+
+	// First we'll get the prepay rfq.
+	prepayRfq, err := s.assetClient.GetRfqForAsset(
+		ctx, quote.PrepayAmount, rfqReq.AssetId,
+		rfqReq.AssetEdgeNode, rfqReq.Expiry,
+		rfqReq.MaxLimitMultiplier,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	prepayAssetRate, err := rfqrpc.UnmarshalFixedPoint(
+		prepayRfq.BidAssetRate,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// The actual invoice swap amount is the requested amount plus
+	// the swap fee minus the prepay amount.
+	invoiceAmt := request.Amount + quote.SwapFee -
+		quote.PrepayAmount
+
+	swapRfq, err := s.assetClient.GetRfqForAsset(
+		ctx, invoiceAmt, rfqReq.AssetId,
+		rfqReq.AssetEdgeNode, rfqReq.Expiry,
+		rfqReq.MaxLimitMultiplier,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	swapAssetRate, err := rfqrpc.UnmarshalFixedPoint(
+		swapRfq.BidAssetRate,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// We'll also want the asset name to verify for the client.
+	assetName, err := s.assetClient.GetAssetName(
+		ctx, rfqReq.AssetId,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return &LoopOutRfq{
+		PrepayRfqId:       prepayRfq.Id,
+		MaxPrepayAssetAmt: prepayRfq.AssetAmount,
+		PrepayAssetRate:   prepayAssetRate,
+		SwapRfqId:         swapRfq.Id,
+		MaxSwapAssetAmt:   swapRfq.AssetAmount,
+		SwapAssetRate:     swapAssetRate,
+		AssetName:         assetName,
+	}, nil
+}

cmd/loop/main.go

@@ -103,6 +103,13 @@ const (
 	//      Amount:                                    50 USD
 	assetAmtFmt = "%-36s %12d %s\n"
 
+	// rateFmt formats an exchange rate into a one line string, intended to
+	// prettify the terminal output. For Instance,
+	// 	fmt.Printf(f, "Exchange rate:", rate, "USD")
+	// prints out as,
+	//      Exchange rate:                            0.0002 USD/SAT
+	rateFmt = "%-36s %12.4f %s/SAT\n"
+
 	// blkFmt formats the number of blocks into a one line string, intended
 	// to prettify the terminal output. For Instance,
 	// 	fmt.Printf(f, "Conf target", target)

cmd/loop/quote.go

@@ -9,6 +9,9 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/lightninglabs/loop"
 	"github.com/lightninglabs/loop/looprpc"
+	"github.com/lightninglabs/taproot-assets/rfqmath"
+	"github.com/lightninglabs/taproot-assets/taprpc/rfqrpc"
+	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/urfave/cli"
 )
@@ -268,8 +271,20 @@ func printQuoteOutResp(req *looprpc.QuoteRequest,
 	totalFee := resp.HtlcSweepFeeSat + resp.SwapFeeSat
 
 	if resp.AssetRfqInfo != nil {
+		assetAmtSwap, err := getAssetAmt(
+			req.Amt, resp.AssetRfqInfo.SwapAssetRate,
+		)
+		if err != nil {
+			fmt.Printf("Error converting asset amount: %v\n", err)
+			return
+		}
+		exchangeRate := float64(assetAmtSwap) / float64(req.Amt)
 		fmt.Printf(assetAmtFmt, "Send off-chain:",
-			resp.AssetRfqInfo.SwapAssetAmt,
+			assetAmtSwap, resp.AssetRfqInfo.AssetName)
+		fmt.Printf(rateFmt, "Exchange rate:",
+			exchangeRate, resp.AssetRfqInfo.AssetName)
+		fmt.Printf(assetAmtFmt, "Limit Send off-chain:",
+			resp.AssetRfqInfo.MaxSwapAssetAmt,
 			resp.AssetRfqInfo.AssetName)
 	} else {
 		fmt.Printf(satAmtFmt, "Send off-chain:", req.Amt)
@@ -288,8 +303,18 @@ func printQuoteOutResp(req *looprpc.QuoteRequest,
 	fmt.Printf(satAmtFmt, "Estimated total fee:", totalFee)
 	fmt.Println()
 	if resp.AssetRfqInfo != nil {
+		assetAmtPrepay, err := getAssetAmt(
+			resp.PrepayAmtSat, resp.AssetRfqInfo.PrepayAssetRate,
+		)
+		if err != nil {
+			fmt.Printf("Error converting asset amount: %v\n", err)
+			return
+		}
 		fmt.Printf(assetAmtFmt, "No show penalty (prepay):",
-			resp.AssetRfqInfo.PrepayAssetAmt,
+			assetAmtPrepay,
+			resp.AssetRfqInfo.AssetName)
+		fmt.Printf(assetAmtFmt, "Limit no show penalty (prepay):",
+			resp.AssetRfqInfo.MaxPrepayAssetAmt,
 			resp.AssetRfqInfo.AssetName)
 	} else {
 		fmt.Printf(satAmtFmt, "No show penalty (prepay):",
@@ -302,3 +327,33 @@ func printQuoteOutResp(req *looprpc.QuoteRequest,
 		time.Unix(int64(req.SwapPublicationDeadline), 0),
 	)
 }
+
+// getAssetAmt returns the asset amount for the given amount in satoshis and
+// the asset rate.
+func getAssetAmt(amt int64, assetRate *looprpc.FixedPoint) (
+	uint64, error) {
+
+	askAssetRate, err := unmarshalFixedPoint(assetRate)
+	if err != nil {
+		return 0, err
+	}
+
+	msatAmt := lnwire.MilliSatoshi((amt * 1000))
+
+	assetAmt := rfqmath.MilliSatoshiToUnits(msatAmt, *askAssetRate)
+
+	return assetAmt.ToUint64(), nil
+}
+
+// unmarshalFixedPoint converts an RPC FixedPoint to a BigIntFixedPoint.
+func unmarshalFixedPoint(fp *looprpc.FixedPoint) (*rfqmath.BigIntFixedPoint,
+	error) {
+
+	// convert the looprpc.FixedPoint to a rfqrpc.FixedPoint
+	rfqrpcFP := &rfqrpc.FixedPoint{
+		Coefficient: fp.Coefficient,
+		Scale:       fp.Scale,
+	}
+
+	return rfqrpc.UnmarshalFixedPoint(rfqrpcFP)
+}