rfq: add AssetRateHint arg to queryBidFromPriceOracle and QueryBidPrice

This update adds an asset rate hint argument to the
`queryBidFromPriceOracle`  negotiator method and the `PriceOracle`
interface's `QueryBidPrice` method.

Author: ffranr

rfq/negotiator.go

@@ -106,8 +106,9 @@ func NewNegotiator(cfg NegotiatorCfg) (*Negotiator, error) {
 // queryBidFromPriceOracle queries the price oracle for a bid price. It returns
 // an appropriate outgoing response message which should be sent to the peer.
 func (n *Negotiator) queryBidFromPriceOracle(peer route.Vertex,
-	assetId *asset.ID, assetGroupKey *btcec.PublicKey,
-	assetAmount uint64) (*rfqmath.BigIntFixedPoint, uint64, error) {
+	assetId *asset.ID, assetGroupKey *btcec.PublicKey, assetAmount uint64,
+	assetRateHint fn.Option[rfqmsg.AssetRate]) (*rfqmath.BigIntFixedPoint,
+	uint64, error) {
 
 	// TODO(ffranr): Optionally accept a peer's proposed ask price as an
 	//  arg to this func and pass it to the price oracle. The price oracle
@@ -120,7 +121,7 @@ func (n *Negotiator) queryBidFromPriceOracle(peer route.Vertex,
 	defer cancel()
 
 	oracleResponse, err := n.cfg.PriceOracle.QueryBidPrice(
-		ctx, assetId, assetGroupKey, assetAmount,
+		ctx, assetId, assetGroupKey, assetAmount, assetRateHint,
 	)
 	if err != nil {
 		return nil, 0, fmt.Errorf("failed to query price oracle for "+
@@ -168,6 +169,7 @@ func (n *Negotiator) HandleOutgoingBuyOrder(buyOrder BuyOrder) error {
 			rate, _, err := n.queryBidFromPriceOracle(
 				*buyOrder.Peer, buyOrder.AssetID,
 				buyOrder.AssetGroupKey, buyOrder.MinAssetAmount,
+				fn.None[rfqmsg.AssetRate](),
 			)
 			if err != nil {
 				// If we fail to query the price oracle for a
@@ -407,7 +409,7 @@ func (n *Negotiator) HandleIncomingSellRequest(
 		// sell to us.
 		assetRate, rateExpiry, err := n.queryBidFromPriceOracle(
 			request.Peer, request.AssetID, request.AssetGroupKey,
-			request.AssetAmount,
+			request.AssetAmount, request.AssetRateHint,
 		)
 		if err != nil {
 			// Send a reject message to the peer.
@@ -692,7 +694,7 @@ func (n *Negotiator) HandleIncomingSellAccept(msg rfqmsg.SellAccept,
 		// by the price oracle with the bid price provided by the peer.
 		assetRate, _, err := n.queryBidFromPriceOracle(
 			msg.Peer, msg.Request.AssetID, nil,
-			msg.Request.AssetAmount,
+			msg.Request.AssetAmount, msg.Request.AssetRateHint,
 		)
 		if err != nil {
 			// The price oracle returned an error. We will return

rfq/oracle.go

@@ -106,8 +106,9 @@ type PriceOracle interface {
 	// The bid price is the amount the oracle suggests a peer should pay
 	// to another peer to receive the specified asset amount.
 	QueryBidPrice(ctx context.Context, assetId *asset.ID,
-		assetGroupKey *btcec.PublicKey,
-		assetAmount uint64) (*OracleResponse, error)
+		assetGroupKey *btcec.PublicKey, assetAmount uint64,
+		assetRateHint fn.Option[rfqmsg.AssetRate]) (
+		*OracleResponse, error)
 }
 
 // RpcPriceOracle is a price oracle that uses an external RPC server to get
@@ -279,8 +280,8 @@ func (r *RpcPriceOracle) QueryAskPrice(ctx context.Context,
 
 // QueryBidPrice returns a bid price for the given asset amount.
 func (r *RpcPriceOracle) QueryBidPrice(ctx context.Context, assetId *asset.ID,
-	assetGroupKey *btcec.PublicKey,
-	maxAssetAmount uint64) (*OracleResponse, error) {
+	assetGroupKey *btcec.PublicKey, maxAssetAmount uint64,
+	assetRateHint fn.Option[rfqmsg.AssetRate]) (*OracleResponse, error) {
 
 	// For now, we only support querying the ask price with an asset ID.
 	if assetId == nil {
@@ -296,6 +297,14 @@ func (r *RpcPriceOracle) QueryBidPrice(ctx context.Context, assetId *asset.ID,
 	// set the subject asset ID.
 	copy(subjectAssetId, assetId[:])
 
+	// Construct the RPC asset rates hint.
+	rpcAssetRatesHint, err := fn.MapOptionZ(
+		assetRateHint, oraclerpc.MarshalAssetRates,
+	).Unpack()
+	if err != nil {
+		return nil, err
+	}
+
 	req := &oraclerpc.QueryAssetRatesRequest{
 		TransactionType: oraclerpc.TransactionType_PURCHASE,
 		SubjectAsset: &oraclerpc.AssetSpecifier{
@@ -309,7 +318,7 @@ func (r *RpcPriceOracle) QueryBidPrice(ctx context.Context, assetId *asset.ID,
 				AssetId: paymentAssetId,
 			},
 		},
-		AssetRatesHint: nil,
+		AssetRatesHint: rpcAssetRatesHint,
 	}
 
 	// Perform query.
@@ -409,7 +418,8 @@ func (m *MockPriceOracle) QueryAskPrice(_ context.Context,
 
 // QueryBidPrice returns a bid price for the given asset amount.
 func (m *MockPriceOracle) QueryBidPrice(_ context.Context, _ *asset.ID,
-	_ *btcec.PublicKey, _ uint64) (*OracleResponse, error) {
+	_ *btcec.PublicKey, _ uint64,
+	_ fn.Option[rfqmsg.AssetRate]) (*OracleResponse, error) {
 
 	// Calculate the rate expiryDelay lifetime.
 	expiry := uint64(time.Now().Unix()) + m.expiryDelay

rfq/oracle_test.go

@@ -262,6 +262,7 @@ func runQueryBidPriceTest(t *testing.T, tc *testCaseQueryBidPrice) {
 
 	resp, err := client.QueryBidPrice(
 		ctx, tc.assetId, tc.assetGroupKey, assetAmount,
+		fn.None[rfqmsg.AssetRate](),
 	)
 
 	// If we expect an error, ensure that it is returned.