Add payinvoice endpoint

controllers/addinvoice.ctrl.go

@@ -47,7 +47,7 @@ func (controller *AddInvoiceController) AddInvoice(c echo.Context) error {
 
 	c.Logger().Infof("Adding invoice: user_id=%v memo=%s value=%v description_hash=%s", userID, body.Memo, body.Amt, body.DescriptionHash)
 
-	invoice, err := controller.svc.AddInvoice(userID, body.Amt, body.Memo, body.DescriptionHash)
+	invoice, err := controller.svc.AddIncomingInvoice(userID, body.Amt, body.Memo, body.DescriptionHash)
 	if err != nil {
 		c.Logger().Errorf("Error creating invoice: %v", err)
 		// TODO: sentry notification

controllers/payinvoice.ctrl.go

@@ -1,6 +1,8 @@
 package controllers
 
 import (
+	"context"
+	"fmt"
 	"net/http"
 
 	"github.com/getAlby/lndhub.go/lib/service"
@@ -18,23 +20,71 @@ func NewPayInvoiceController(svc *service.LndhubService) *PayInvoiceController {
 
 // PayInvoice : Pay invoice Controller
 func (controller *PayInvoiceController) PayInvoice(c echo.Context) error {
-	userId := c.Get("UserID").(int64)
+	userID := c.Get("UserID").(int64)
 	var reqBody struct {
 		Invoice string `json:"invoice" validate:"required"`
 		Amount  int    `json:"amount" validate:"omitempty,gte=0"`
 	}
 
 	if err := c.Bind(&reqBody); err != nil {
+		c.Logger().Errorf("Failed to load payinvoice request body: %v", err)
 		return c.JSON(http.StatusBadRequest, echo.Map{
-			"message": "failed to bind json",
+			"error":   true,
+			"code":    8,
+			"message": "Bad arguments",
 		})
 	}
 
 	if err := c.Validate(&reqBody); err != nil {
+		c.Logger().Errorf("Invalid payinvoice request body: %v", err)
 		return c.JSON(http.StatusBadRequest, echo.Map{
-			"message": "invalid request",
+			"error":   true,
+			"code":    8,
+			"message": "Bad arguments",
 		})
 	}
-	//TODO json response
-	return controller.svc.Payinvoice(userId, reqBody.Invoice)
+
+	paymentRequest := reqBody.Invoice
+	decodedPaymentRequest, err := controller.svc.DecodePaymentRequest(paymentRequest)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, echo.Map{
+			"error":   true,
+			"code":    8,
+			"message": "Bad arguments",
+		})
+	}
+	c.Logger().Info("%v", decodedPaymentRequest)
+
+	invoice, err := controller.svc.AddOutgoingInvoice(userID, paymentRequest, *decodedPaymentRequest)
+	if err != nil {
+		c.Logger().Errorf("Error creating invoice: %v", err)
+		// TODO: sentry notification
+		return c.JSON(http.StatusInternalServerError, nil)
+	}
+
+	currentBalance, err := controller.svc.CurrentUserBalance(context.TODO(), userID)
+	if err != nil {
+		return err
+	}
+
+	if currentBalance < invoice.Amount {
+		c.Logger().Errorf("User does not have enough balance invoice_id=%v user_id=%v balance=%v amount=%v", invoice.ID, userID, currentBalance, invoice.Amount)
+
+		return c.JSON(http.StatusBadRequest, echo.Map{
+			"error":   true,
+			"code":    2,
+			"message": fmt.Sprintf("not enough balance (%v). Make sure you have at least 1%% reserved for potential fees", currentBalance),
+		})
+	}
+
+	entry, err := controller.svc.PayInvoice(invoice)
+	if err != nil {
+		c.Logger().Errorf("Failed: %v", err)
+		return c.JSON(http.StatusBadRequest, echo.Map{
+			"error":   true,
+			"code":    10,
+			"message": fmt.Sprintf("Payment failed. Does the receiver have enough inbound capacity? (%v)", err),
+		})
+	}
+	return c.JSON(http.StatusOK, &entry)
 }

db/models/invoice.go

@@ -9,17 +9,18 @@ import (
 
 // Invoice : Invoice Model
 type Invoice struct {
-	ID              uint         `json:"id" bun:",pk,autoincrement"`
-	Type            string       `json:"type"`
-	UserID          int64        `json:"user_id"`
+	ID              int64        `json:"id" bun:",pk,autoincrement"`
+	Type            string       `json:"type" validate:"required"`
+	UserID          int64        `json:"user_id" validate:"required"`
 	User            *User        `bun:"rel:belongs-to,join:user_id=id"`
-	Amount          int64        `json:"amount"`
+	Amount          int64        `json:"amount" validate:"gte=0"`
 	Memo            string       `json:"memo"`
-	DescriptionHash string       `json:"description_hash"`
+	DescriptionHash string       `json:"description_hash" bun:",nullzero"`
 	PaymentRequest  string       `json:"payment_request"`
 	RHash           string       `json:"r_hash"`
-	State           string       `json:"state"`
-	AddIndex        uint64       `json:"add_index"`
+	Preimage        string       `json:"preimage" bun:",nullzero"`
+	State           string       `json:"state" bun:",default:'initialized'"`
+	AddIndex        uint64       `json:"add_index" bun:",nullzero"`
 	CreatedAt       time.Time    `bun:",nullzero,notnull,default:current_timestamp"`
 	UpdatedAt       bun.NullTime `json:"updated_at"`
 	SettledAt       bun.NullTime `json:"settled_at"`

lib/service/invoices.go

@@ -2,12 +2,19 @@ package service
 
 import (
 	"context"
+	"database/sql"
 	"encoding/hex"
+	"errors"
 	"math/rand"
+	"strings"
+	"time"
 
+	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/getAlby/lndhub.go/db/models"
 	"github.com/labstack/gommon/random"
 	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/zpay32"
+	"github.com/uptrace/bun/schema"
 )
 
 func (svc *LndhubService) FindInvoiceByPaymentHash(userId int64, rHash string) (*models.Invoice, error) {
@@ -20,28 +27,120 @@ func (svc *LndhubService) FindInvoiceByPaymentHash(userId int64, rHash string) (
 	return &invoice, nil
 }
 
-func (svc *LndhubService) Payinvoice(userId int64, invoice string) error {
+func (svc *LndhubService) PayInvoice(invoice *models.Invoice) (*models.TransactionEntry, error) {
+	userId := invoice.UserID
+
+	// Get the user's current and outgoing account for the transaction entry
 	debitAccount, err := svc.AccountFor(context.TODO(), "current", userId)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	creditAccount, err := svc.AccountFor(context.TODO(), "outgoing", userId)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	entry := models.TransactionEntry{
 		UserID:          userId,
+		InvoiceID:       invoice.ID,
 		CreditAccountID: creditAccount.ID,
 		DebitAccountID:  debitAccount.ID,
-		Amount:          1000,
-	}
-	_, err = svc.DB.NewInsert().Model(&entry).Exec(context.TODO())
-	return err
-
+		Amount:          invoice.Amount,
 	}
 
-func (svc *LndhubService) AddInvoice(userID int64, amount int64, memo, descriptionHash string) (*models.Invoice, error) {
+	// Start a DB transaction
+	// We rollback anything on error (only the invoice that was passed in to the PayInvoice calls stays in the DB)
+	tx, err := svc.DB.BeginTx(context.TODO(), &sql.TxOptions{})
+	if err != nil {
+		return &entry, err
+	}
+	_, err = tx.NewInsert().Model(&entry).Exec(context.TODO())
+	if err != nil {
+		tx.Rollback()
+		return &entry, err
+	}
+
+	// TODO: set fee limit
+	feeLimit := lnrpc.FeeLimit{
+		Limit: &lnrpc.FeeLimit_Percent{
+			Percent: 2,
+		},
+	}
+
+	// Prepare the LNRPC call
+	sendPaymentRequest := lnrpc.SendRequest{
+		PaymentRequest: invoice.PaymentRequest,
+		Amt:            invoice.Amount,
+		FeeLimit:       &feeLimit,
+	}
+	lndClient := *svc.LndClient
+
+	// Execute the payment
+	sendPaymentResult, err := lndClient.SendPaymentSync(context.TODO(), &sendPaymentRequest)
+	if err != nil {
+		tx.Rollback()
+		return &entry, err
+	}
+
+	// If there was a payment error we rollback and return an error
+	if sendPaymentResult.GetPaymentError() != "" || sendPaymentResult.GetPaymentPreimage() == nil {
+		tx.Rollback()
+		return &entry, errors.New(sendPaymentResult.GetPaymentError())
+	}
+
+	// The payment was successful.
+	// We store the preimage and mark the invoice as settled
+	preimage := sendPaymentResult.GetPaymentPreimage()
+	invoice.Preimage = hex.EncodeToString(preimage[:])
+	invoice.State = "settled"
+	invoice.SettledAt = schema.NullTime{Time: time.Now()}
+
+	_, err = svc.DB.NewUpdate().Model(invoice).WherePK().Exec(context.TODO())
+	if err != nil {
+		tx.Rollback()
+		return &entry, err
+	}
+
+	// Commit the DB transaction. Done, everything worked
+	err = tx.Commit()
+	if err != nil {
+		return &entry, err
+	}
+
+	return &entry, err
+}
+
+func (svc *LndhubService) AddOutgoingInvoice(userID int64, paymentRequest string, decodedInvoice zpay32.Invoice) (*models.Invoice, error) {
+	// Initialize new DB invoice
+	invoice := models.Invoice{
+		Type:           "outgoing",
+		UserID:         userID,
+		Memo:           *decodedInvoice.Description,
+		PaymentRequest: paymentRequest,
+		State:          "initialized",
+	}
+	if decodedInvoice.DescriptionHash != nil {
+		dh := *decodedInvoice.DescriptionHash
+		invoice.DescriptionHash = hex.EncodeToString(dh[:])
+	}
+	if decodedInvoice.PaymentHash != nil {
+		ph := *decodedInvoice.PaymentHash
+		invoice.RHash = hex.EncodeToString(ph[:])
+	}
+	if decodedInvoice.MilliSat != nil {
+		msat := decodedInvoice.MilliSat
+		invoice.Amount = int64(msat.ToSatoshis())
+	}
+
+	// Save invoice
+	_, err := svc.DB.NewInsert().Model(&invoice).Exec(context.TODO())
+	if err != nil {
+		return nil, err
+	}
+	return &invoice, nil
+}
+
+func (svc *LndhubService) AddIncomingInvoice(userID int64, amount int64, memo, descriptionHash string) (*models.Invoice, error) {
 	// Initialize new DB invoice
 	invoice := models.Invoice{
 		Type:            "incoming",
@@ -86,6 +185,10 @@ func (svc *LndhubService) AddInvoice(userID int64, amount int64, memo, descripti
 	return &invoice, nil
 }
 
+func (svc *LndhubService) DecodePaymentRequest(bolt11 string) (*zpay32.Invoice, error) {
+	return zpay32.Decode(bolt11, ChainFromCurrency(bolt11[2:]))
+}
+
 const hexBytes = random.Hex
 
 func makePreimageHex() []byte {
@@ -95,3 +198,15 @@ func makePreimageHex() []byte {
 	}
 	return b
 }
+
+func ChainFromCurrency(currency string) *chaincfg.Params {
+	if strings.HasPrefix(currency, "bcrt") {
+		return &chaincfg.RegressionNetParams
+	} else if strings.HasPrefix(currency, "tb") {
+		return &chaincfg.TestNet3Params
+	} else if strings.HasPrefix(currency, "sb") {
+		return &chaincfg.SimNetParams
+	} else {
+		return &chaincfg.MainNetParams
+	}
+}