return invoice status in lightning client

cashu/cashu.go

@@ -173,7 +173,7 @@ var (
 	ProofAlreadyUsedErr      = Error{Detail: "proofs already used", Code: ProofsErrCode}
 	InvalidProofErr          = Error{Detail: "invalid proof", Code: ProofsErrCode}
 	InputsBelowOutputs       = Error{Detail: "amount of input proofs is below amount of outputs", Code: ProofsErrCode}
-	MeltQuoteNotExistErr     = Error{Detail: "melt quote does not exist", Code: QuoteErrCode}
+	QuoteNotExistErr         = Error{Detail: "quote does not exist", Code: QuoteErrCode}
 	InsufficientProofsAmount = Error{Detail: "insufficient amount in proofs", Code: ProofsErrCode}
 	InvalidKeysetProof       = Error{Detail: "proof from an invalid keyset", Code: ProofsErrCode}
 	InvalidSignatureRequest  = Error{Detail: "requested signature from non-active keyset", Code: KeysetErrCode}

mint/lightning/lightning.go

@@ -12,7 +12,7 @@ const (
 // Client interface to interact with a Lightning backend
 type Client interface {
 	CreateInvoice(amount uint64) (Invoice, error)
-	InvoiceSettled(hash string) (bool, error)
+	InvoiceStatus(hash string) (Invoice, error)
 	FeeReserve(amount uint64) uint64
 	SendPayment(request string, amount uint64) (string, error)
 }
@@ -39,6 +39,7 @@ type Invoice struct {
 	Id             string // random id generated by mint
 	PaymentRequest string
 	PaymentHash    string
+	Preimage       string
 	Settled        bool
 	Redeemed       bool
 	Amount         uint64

mint/lightning/lnd.go

@@ -99,19 +99,26 @@ func (lnd *LndClient) CreateInvoice(amount uint64) (Invoice, error) {
 	return invoice, nil
 }
 
-func (lnd *LndClient) InvoiceSettled(hash string) (bool, error) {
+func (lnd *LndClient) InvoiceStatus(hash string) (Invoice, error) {
 	hashBytes, err := hex.DecodeString(hash)
 	if err != nil {
-		return false, errors.New("invalid hash provided")
+		return Invoice{}, errors.New("invalid hash provided")
 	}
 
 	paymentHashRequest := lnrpc.PaymentHash{RHash: hashBytes}
 	lookupInvoiceResponse, err := lnd.grpcClient.LookupInvoice(context.Background(), &paymentHashRequest)
 	if err != nil {
-		return false, fmt.Errorf("error getting invoice status: %v", err)
+		return Invoice{}, err
 	}
 
-	return lookupInvoiceResponse.State == lnrpc.Invoice_SETTLED, nil
+	invoice := Invoice{
+		PaymentRequest: lookupInvoiceResponse.PaymentRequest,
+		PaymentHash:    hash,
+		Settled:        lookupInvoiceResponse.State == lnrpc.Invoice_SETTLED,
+		Amount:         uint64(lookupInvoiceResponse.Value),
+	}
+
+	return invoice, nil
 }
 
 func (lnd *LndClient) FeeReserve(amount uint64) uint64 {

mint/mint.go

@@ -134,18 +134,25 @@ func (m *Mint) GetMintQuoteState(method, quoteId string) (nut04.PostMintQuoteBol
 
 	invoice := m.db.GetInvoice(quoteId)
 	if invoice == nil {
-		return nut04.PostMintQuoteBolt11Response{}, cashu.InvoiceNotExistErr
+		return nut04.PostMintQuoteBolt11Response{}, cashu.QuoteNotExistErr
 	}
 
 	// check if the invoice has been paid
-	settled, _ := m.LightningClient.InvoiceSettled(invoice.PaymentHash)
-	if settled != invoice.Settled {
-		invoice.Settled = settled
+	status, err := m.LightningClient.InvoiceStatus(invoice.PaymentHash)
+	if err != nil {
+		return nut04.PostMintQuoteBolt11Response{}, fmt.Errorf("error checking invoice status: %v", err)
+	}
+	if status.Settled && status.Settled != invoice.Settled {
+		invoice.Settled = status.Settled
 		m.db.SaveInvoice(*invoice)
 	}
 
-	quoteState := nut04.PostMintQuoteBolt11Response{Quote: invoice.Id,
-		Request: invoice.PaymentRequest, Paid: settled, Expiry: invoice.Expiry}
+	quoteState := nut04.PostMintQuoteBolt11Response{
+		Quote:   invoice.Id,
+		Request: invoice.PaymentRequest,
+		Paid:    invoice.Settled,
+		Expiry:  invoice.Expiry,
+	}
 	return quoteState, nil
 }
 
@@ -163,8 +170,11 @@ func (m *Mint) MintTokens(method, id string, blindedMessages cashu.BlindedMessag
 
 	var blindedSignatures cashu.BlindedSignatures
 
-	settled, _ := m.LightningClient.InvoiceSettled(invoice.PaymentHash)
-	if settled {
+	status, err := m.LightningClient.InvoiceStatus(invoice.PaymentHash)
+	if err != nil {
+		return nil, fmt.Errorf("error checking invoice status: %v", err)
+	}
+	if status.Settled {
 		if invoice.Redeemed {
 			return nil, cashu.InvoiceTokensIssuedErr
 		}
@@ -295,7 +305,7 @@ func (m *Mint) GetMeltQuoteState(method, quoteId string) (MeltQuote, error) {
 
 	meltQuote := m.db.GetMeltQuote(quoteId)
 	if meltQuote == nil {
-		return MeltQuote{}, cashu.MeltQuoteNotExistErr
+		return MeltQuote{}, cashu.QuoteNotExistErr
 	}
 
 	return *meltQuote, nil
@@ -310,7 +320,7 @@ func (m *Mint) MeltTokens(method, quoteId string, proofs cashu.Proofs) (MeltQuot
 
 	meltQuote := m.db.GetMeltQuote(quoteId)
 	if meltQuote == nil {
-		return MeltQuote{}, cashu.MeltQuoteNotExistErr
+		return MeltQuote{}, cashu.QuoteNotExistErr
 	}
 
 	proofsAmount := proofs.Amount()

mint/server.go

@@ -191,7 +191,7 @@ func (ms *MintServer) mintRequest(rw http.ResponseWriter, req *http.Request) {
 	reqMintResponse, err := ms.mint.RequestMintQuote(method, mintReq.Amount, mintReq.Unit)
 	if err != nil {
 		cashuErr, ok := err.(*cashu.Error)
-		// RequestMintQuote will return err from lightning backend if invoice
+		// note: RequestMintQuote will return err from lightning backend if invoice
 		// generation fails. Log that err from backend but return generic response to request
 		if ok && cashuErr.Code == cashu.InvoiceErrCode {
 			ms.writeErr(rw, req, cashu.StandardErr, cashuErr.Error())
@@ -218,6 +218,12 @@ func (ms *MintServer) mintQuoteState(rw http.ResponseWriter, req *http.Request)
 
 	mintQuoteStateResponse, err := ms.mint.GetMintQuoteState(method, quoteId)
 	if err != nil {
+		// if error is from lnd, log it but throw generic response
+		_, ok := err.(*cashu.Error)
+		if !ok {
+			ms.writeErr(rw, req, cashu.StandardErr, err.Error())
+		}
+
 		ms.writeErr(rw, req, err)
 		return
 	}
@@ -243,6 +249,12 @@ func (ms *MintServer) mintTokensRequest(rw http.ResponseWriter, req *http.Reques
 
 	blindedSignatures, err := ms.mint.MintTokens(method, mintReq.Quote, mintReq.Outputs)
 	if err != nil {
+		// if error is from lnd, log it but throw generic response
+		_, ok := err.(*cashu.Error)
+		if !ok {
+			ms.writeErr(rw, req, cashu.StandardErr, err.Error())
+		}
+
 		ms.writeErr(rw, req, err)
 		return
 	}