loopout/asset: add asset rate

Author: sputn1ck

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"
@@ -661,6 +662,10 @@ 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 {
+		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()
@@ -680,6 +685,13 @@ func (s *Client) LoopOutQuote(ctx context.Context,
 			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 -
@@ -694,6 +706,13 @@ func (s *Client) LoopOutQuote(ctx context.Context,
 			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,
@@ -705,8 +724,10 @@ func (s *Client) LoopOutQuote(ctx context.Context,
 		loopOutQuote.LoopOutRfq = &LoopOutRfq{
 			PrepayRfqId:       prepayRfq.Id,
 			MaxPrepayAssetAmt: prepayRfq.AssetAmount,
+			PrepayAssetRate:   prepayAssetRate,
 			SwapRfqId:         swapRfq.Id,
 			MaxSwapAssetAmt:   swapRfq.AssetAmount,
+			SwapAssetRate:     swapAssetRate,
 			AssetName:         assetName,
 		}
 	}

interface.go

@@ -6,6 +6,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/lightninglabs/loop/loopdb"
 	"github.com/lightninglabs/loop/swap"
+	"github.com/lightninglabs/taproot-assets/rfqmath"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/zpay32"
@@ -228,13 +229,20 @@ type LoopOutRfq struct {
 	// used to pay for the prepay invoice.
 	MaxPrepayAssetAmt uint64
 
+	// PrepayAssetRate is the rate at which the asset is exchanged for
+	// bitcoin.
+	PrepayAssetRate *rfqmath.BigIntFixedPoint
+
 	// SwapRfqId is the ID of the swap RFQ.
 	SwapRfqId []byte
 
 	// MaxSwapAssetAmt is the maxmimum amount of the asset that will be used
 	// to pay for the swap invoice.
 	MaxSwapAssetAmt uint64
 
+	// SwapAssetRate is the rate at which the asset is exchanged for bitcoin.
+	SwapAssetRate *rfqmath.BigIntFixedPoint
+
 	// AssetName is the human readable name of the asset.
 	AssetName string
 }

loopd/swapclient_server.go

@@ -804,8 +804,16 @@ func (s *swapClientServer) LoopOutQuote(ctx context.Context,
 		response.AssetRfqInfo = &looprpc.AssetRfqInfo{
 			PrepayRfqId:       quote.LoopOutRfq.PrepayRfqId,
 			MaxPrepayAssetAmt: quote.LoopOutRfq.MaxPrepayAssetAmt,
+			PrepayAssetRate: &looprpc.FixedPoint{
+				Scale:       uint32(quote.LoopOutRfq.PrepayAssetRate.Scale),
+				Coefficient: quote.LoopOutRfq.PrepayAssetRate.Coefficient.String(),
+			},
 			SwapRfqId:       quote.LoopOutRfq.SwapRfqId,
 			MaxSwapAssetAmt: quote.LoopOutRfq.MaxSwapAssetAmt,
+			SwapAssetRate: &looprpc.FixedPoint{
+				Scale:       uint32(quote.LoopOutRfq.SwapAssetRate.Scale),
+				Coefficient: quote.LoopOutRfq.SwapAssetRate.Coefficient.String(),
+			},
 			AssetName: quote.LoopOutRfq.AssetName,
 		}
 	}