multi: use InvoiceClient in NewLndChallenger

Stop creating the connection inside the `NewLndChallenger`. That will
allow us reuse the function with an LNC connection.

Author: positiveblue

aperture.go

@@ -24,6 +24,7 @@ import (
 	"github.com/lightninglabs/aperture/mint"
 	"github.com/lightninglabs/aperture/proxy"
 	"github.com/lightninglabs/lightning-node-connect/hashmailrpc"
+	"github.com/lightninglabs/lndclient"
 	"github.com/lightningnetwork/lnd"
 	"github.com/lightningnetwork/lnd/build"
 	"github.com/lightningnetwork/lnd/cert"
@@ -293,8 +294,19 @@ func (a *Aperture) Start(errChan chan error) error {
 	}
 
 	if !a.cfg.Authenticator.Disable {
+		authCfg := a.cfg.Authenticator
+		client, err := lndclient.NewBasicClient(
+			authCfg.LndHost, authCfg.TLSPath, authCfg.MacDir,
+			authCfg.Network, lndclient.MacFilename(
+				invoiceMacaroonName,
+			),
+		)
+		if err != nil {
+			return err
+		}
+
 		a.challenger, err = NewLndChallenger(
-			a.cfg.Authenticator, genInvoiceReq, errChan,
+			client, genInvoiceReq, errChan,
 		)
 		if err != nil {
 			return err

challenger.go

@@ -11,7 +11,6 @@ import (
 
 	"github.com/lightninglabs/aperture/auth"
 	"github.com/lightninglabs/aperture/mint"
-	"github.com/lightninglabs/lndclient"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lntypes"
 	"google.golang.org/grpc"
@@ -66,23 +65,16 @@ const (
 	invoiceMacaroonName = "invoice.macaroon"
 )
 
-// NewLndChallenger creates a new challenger that uses the given connection
-// details to connect to an lnd backend to create payment challenges.
-func NewLndChallenger(cfg *AuthConfig, genInvoiceReq InvoiceRequestGenerator,
+// NewLndChallenger creates a new challenger that uses the given connection to
+// an lnd backend to create payment challenges.
+func NewLndChallenger(client InvoiceClient,
+	genInvoiceReq InvoiceRequestGenerator,
 	errChan chan<- error) (*LndChallenger, error) {
 
 	if genInvoiceReq == nil {
 		return nil, fmt.Errorf("genInvoiceReq cannot be nil")
 	}
 
-	client, err := lndclient.NewBasicClient(
-		cfg.LndHost, cfg.TLSPath, cfg.MacDir, cfg.Network,
-		lndclient.MacFilename(invoiceMacaroonName),
-	)
-	if err != nil {
-		return nil, err
-	}
-
 	invoicesMtx := &sync.Mutex{}
 	return &LndChallenger{
 		client:        client,