rfq+rfqmsg: use new AssetRate type in NewBuyRequest func argument

As a result of this change the price oracle's quote expiry value is
used in the request constructor.

rfq/negotiator.go

@@ -162,11 +162,11 @@ func (n *Negotiator) HandleOutgoingBuyOrder(buyOrder BuyOrder) error {
 		// We calculate a proposed bid price for our peer's
 		// consideration. If a price oracle is not specified we will
 		// skip this step.
-		var assetRateBid fn.Option[rfqmath.BigIntFixedPoint]
+		var assetRateHint fn.Option[rfqmsg.AssetRate]
 
 		if n.cfg.PriceOracle != nil {
 			// Query the price oracle for a bid price.
-			rate, _, err := n.queryBidFromPriceOracle(
+			rate, expiryUnix, err := n.queryBidFromPriceOracle(
 				*buyOrder.Peer, buyOrder.AssetID,
 				buyOrder.AssetGroupKey, buyOrder.MinAssetAmount,
 				fn.None[rfqmsg.AssetRate](),
@@ -180,13 +180,16 @@ func (n *Negotiator) HandleOutgoingBuyOrder(buyOrder BuyOrder) error {
 					"request: %v", err)
 			}
 
-			assetRateBid = fn.Some[rfqmath.BigIntFixedPoint](*rate)
+			expiry := time.Unix(int64(expiryUnix), 0)
+			assetRateHint = fn.Some[rfqmsg.AssetRate](
+				rfqmsg.NewAssetRate(*rate, expiry),
+			)
 		}
 
 		request, err := rfqmsg.NewBuyRequest(
 			*buyOrder.Peer, buyOrder.AssetID,
 			buyOrder.AssetGroupKey, buyOrder.MinAssetAmount,
-			assetRateBid,
+			assetRateHint,
 		)
 		if err != nil {
 			err := fmt.Errorf("unable to create buy request "+

rfqmsg/buy_request.go

@@ -8,7 +8,6 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightninglabs/taproot-assets/fn"
-	"github.com/lightninglabs/taproot-assets/rfqmath"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/tlv"
 )
@@ -52,21 +51,14 @@ type BuyRequest struct {
 // NewBuyRequest creates a new asset buy quote request.
 func NewBuyRequest(peer route.Vertex, assetID *asset.ID,
 	assetGroupKey *btcec.PublicKey, assetAmount uint64,
-	rateHint fn.Option[rfqmath.BigIntFixedPoint]) (*BuyRequest, error) {
+	assetRateHint fn.Option[AssetRate]) (*BuyRequest, error) {
 
 	id, err := NewID()
 	if err != nil {
 		return nil, fmt.Errorf("unable to generate random "+
 			"quote request id: %w", err)
 	}
 
-	// Construct a suggested asset rate if a rate hint is provided.
-	var assetRateHint fn.Option[AssetRate]
-	rateHint.WhenSome(func(rate rfqmath.BigIntFixedPoint) {
-		expiry := time.Now().Add(DefaultQuoteLifetime).UTC()
-		assetRateHint = fn.Some(NewAssetRate(rate, expiry))
-	})
-
 	return &BuyRequest{
 		Peer:          peer,
 		Version:       latestBuyRequestVersion,