lnd: modify sendcoin rpc impl for select utxos

Signed-off-by: Ononiwu Maureen <59079323+Chinwendu20@users.noreply.github.com>

rpcserver.go

@@ -1067,7 +1067,8 @@ func allowCORS(handler http.Handler, origins []string) http.Handler {
 // address to a specified output value to be sent to that address.
 func (r *rpcServer) sendCoinsOnChain(paymentMap map[string]int64,
 	feeRate chainfee.SatPerKWeight, minConfs int32, label string,
-	strategy wallet.CoinSelectionStrategy) (*chainhash.Hash, error) {
+	strategy wallet.CoinSelectionStrategy,
+	selectedUtxos fn.Set[wire.OutPoint]) (*chainhash.Hash, error) {
 
 	outputs, err := addrPairsToOutputs(paymentMap, r.cfg.ActiveNetParams.Params)
 	if err != nil {
@@ -1077,7 +1078,7 @@ func (r *rpcServer) sendCoinsOnChain(paymentMap map[string]int64,
 	// We first do a dry run, to sanity check we won't spend our wallet
 	// balance below the reserved amount.
 	authoredTx, err := r.server.cc.Wallet.CreateSimpleTx(
-		nil, outputs, feeRate, minConfs, strategy, true,
+		selectedUtxos, outputs, feeRate, minConfs, strategy, true,
 	)
 	if err != nil {
 		return nil, err
@@ -1098,7 +1099,7 @@ func (r *rpcServer) sendCoinsOnChain(paymentMap map[string]int64,
 	// If that checks out, we're fairly confident that creating sending to
 	// these outputs will keep the wallet balance above the reserve.
 	tx, err := r.server.cc.Wallet.SendOutputs(
-		nil, outputs, feeRate, minConfs, label, strategy,
+		selectedUtxos, outputs, feeRate, minConfs, label, strategy,
 	)
 	if err != nil {
 		return nil, err
@@ -1290,9 +1291,9 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 	}
 
 	rpcsLog.Infof("[sendcoins] addr=%v, amt=%v, sat/kw=%v, min_confs=%v, "+
-		"send_all=%v",
+		"send_all=%v, select_outpoints=%v",
 		in.Addr, btcutil.Amount(in.Amount), int64(feePerKw), minConfs,
-		in.SendAll)
+		in.SendAll, len(in.Outpoints))
 
 	// Decode the address receiving the coins, we need to check whether the
 	// address is valid for this network.
@@ -1337,6 +1338,22 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 	wallet := r.server.cc.Wallet
 	maxFeeRate := r.cfg.Sweeper.MaxFeeRate.FeePerKWeight()
 
+	var selectOutpoints fn.Set[wire.OutPoint]
+	if len(in.Outpoints) != 0 {
+		wireOutpoints, err := toWireOutpoints(in.Outpoints)
+		if err != nil {
+			return nil, fmt.Errorf("can't create outpoints "+
+				"%w", err)
+		}
+
+		if fn.HasDuplicates(wireOutpoints) {
+			return nil, fmt.Errorf("selected outpoints contain " +
+				"duplicate values")
+		}
+
+		selectOutpoints = fn.NewSet(wireOutpoints...)
+	}
+
 	// If the send all flag is active, then we'll attempt to sweep all the
 	// coins in the wallet in a single transaction (if possible),
 	// otherwise, we'll respect the amount, and attempt a regular 2-output
@@ -1363,7 +1380,7 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 		sweepTxPkg, err := sweep.CraftSweepAllTx(
 			feePerKw, maxFeeRate, uint32(bestHeight), nil,
 			targetAddr, wallet, wallet, wallet.WalletController,
-			r.server.cc.Signer, minConfs, nil,
+			r.server.cc.Signer, minConfs, selectOutpoints,
 		)
 		if err != nil {
 			return nil, err
@@ -1417,7 +1434,7 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 				feePerKw, maxFeeRate, uint32(bestHeight),
 				outputs, targetAddr, wallet, wallet,
 				wallet.WalletController,
-				r.server.cc.Signer, minConfs, nil,
+				r.server.cc.Signer, minConfs, selectOutpoints,
 			)
 			if err != nil {
 				return nil, err
@@ -1443,7 +1460,7 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 			return nil, err
 		}
 
-		rpcsLog.Debugf("Sweeping all coins from wallet to addr=%v, "+
+		rpcsLog.Debugf("Sweeping coins from wallet to addr=%v, "+
 			"with tx=%v", in.Addr, spew.Sdump(sweepTxPkg.SweepTx))
 
 		// As our sweep transaction was created, successfully, we'll
@@ -1468,8 +1485,8 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 		paymentMap := map[string]int64{targetAddr.String(): in.Amount}
 		err := wallet.WithCoinSelectLock(func() error {
 			newTXID, err := r.sendCoinsOnChain(
-				paymentMap, feePerKw, minConfs,
-				label, coinSelectionStrategy,
+				paymentMap, feePerKw, minConfs, label,
+				coinSelectionStrategy, selectOutpoints,
 			)
 			if err != nil {
 				return err
@@ -1540,8 +1557,8 @@ func (r *rpcServer) SendMany(ctx context.Context,
 	wallet := r.server.cc.Wallet
 	err = wallet.WithCoinSelectLock(func() error {
 		sendManyTXID, err := r.sendCoinsOnChain(
-			in.AddrToAmount, feePerKw, minConfs,
-			label, coinSelectionStrategy,
+			in.AddrToAmount, feePerKw, minConfs, label,
+			coinSelectionStrategy, nil,
 		)
 		if err != nil {
 			return err