From aa584d2cb5dd0018c1536b07e9532d9ee347f04e Mon Sep 17 00:00:00 2001
From: ekzyis <ekzyis@ekzy.is>
Date: Fri, 27 Dec 2024 01:52:47 +0100
Subject: [PATCH] Phoenixd webhook handler

---
 lightning/lightning.go         | 17 ++++++-
 lightning/phoenixd/phoenixd.go | 88 +++++++++++++++++++++++++++++++++-
 server/server.go               | 12 +++++
 3 files changed, 113 insertions(+), 4 deletions(-)

diff --git a/lightning/lightning.go b/lightning/lightning.go
index a6fc31e..c7ee255 100644
--- a/lightning/lightning.go
+++ b/lightning/lightning.go
@@ -1,7 +1,20 @@
 package lightning
 
-type Bolt11 string
+import "time"
+
+type PaymentRequest string
 
 type Lightning interface {
-	CreateInvoice(msats int64, description string) (Bolt11, error)
+	CreateInvoice(msats int64, description string) (PaymentRequest, error)
+	GetInvoice(paymentHash string) (*Invoice, error)
+}
+
+type Invoice struct {
+	PaymentHash    string
+	Preimage       string
+	Msats          int64
+	Description    string
+	PaymentRequest string
+	CreatedAt      time.Time
+	ConfirmedAt    time.Time
 }
diff --git a/lightning/phoenixd/phoenixd.go b/lightning/phoenixd/phoenixd.go
index 7f0ca99..c2d2eb1 100644
--- a/lightning/phoenixd/phoenixd.go
+++ b/lightning/phoenixd/phoenixd.go
@@ -9,8 +9,10 @@ import (
 	"net/url"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/ekzyis/zaply/lightning"
+	"github.com/labstack/echo/v4"
 )
 
 type Phoenixd struct {
@@ -53,7 +55,7 @@ func WithPhoenixdWebhookUrl(webhookUrl string) func(*Phoenixd) *Phoenixd {
 	}
 }
 
-func (p *Phoenixd) CreateInvoice(msats int64, description string) (lightning.Bolt11, error) {
+func (p *Phoenixd) CreateInvoice(msats int64, description string) (lightning.PaymentRequest, error) {
 	values := url.Values{}
 	values.Add("amountSat", strconv.FormatInt(msats/1000, 10))
 	values.Add("description", description)
@@ -94,5 +96,87 @@ func (p *Phoenixd) CreateInvoice(msats int64, description string) (lightning.Bol
 		return "", err
 	}
 
-	return lightning.Bolt11(response.Serialized), nil
+	return lightning.PaymentRequest(response.Serialized), nil
+}
+
+func (p *Phoenixd) GetInvoice(paymentHash string) (*lightning.Invoice, error) {
+	endpoint := p.url.JoinPath("payments/incoming", paymentHash)
+
+	req, err := http.NewRequest("GET", endpoint.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+	if p.limitedAccessToken != "" {
+		req.SetBasicAuth("", p.limitedAccessToken)
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("phoenixd %s: %s", resp.Status, string(body))
+	}
+
+	var response struct {
+		PaymentHash string `json:"paymentHash"`
+		Preimage    string `json:"preimage"`
+		Msats       int64  `json:"receivedSat"`
+		Description string `json:"description"`
+		CreatedAt   int64  `json:"createdAt"`
+		ConfirmedAt int64  `json:"completedAt"`
+	}
+	if err := json.Unmarshal(body, &response); err != nil {
+		return nil, err
+	}
+
+	createdAt := time.Unix(response.CreatedAt/1000, 0)
+	var confirmedAt time.Time
+	if response.ConfirmedAt != 0 {
+		confirmedAt = time.Unix(response.ConfirmedAt/1000, 0)
+	}
+
+	return &lightning.Invoice{
+		PaymentHash: response.PaymentHash,
+		Preimage:    response.Preimage,
+		Msats:       response.Msats,
+		Description: response.Description,
+		CreatedAt:   createdAt,
+		ConfirmedAt: confirmedAt,
+	}, nil
+}
+
+func (p *Phoenixd) WebhookHandler(c echo.Context) error {
+	go func() {
+		var webhook struct {
+			Type        string `json:"type"`
+			AmountSat   int64  `json:"amountSat"`
+			PaymentHash string `json:"paymentHash"`
+		}
+		if err := c.Bind(&webhook); err != nil {
+			c.Logger().Error(err)
+			return
+		}
+
+		inv, err := p.GetInvoice(webhook.PaymentHash)
+		if err != nil {
+			c.Logger().Error(err)
+			return
+		}
+
+		log.Printf(
+			"payment received: %s | %d msats | %s | %s | %s",
+			inv.PaymentHash, inv.Msats, inv.Description,
+			inv.CreatedAt.Format(time.RFC3339), inv.ConfirmedAt.Format(time.RFC3339),
+		)
+	}()
+
+	return c.NoContent(http.StatusOK)
 }
diff --git a/server/server.go b/server/server.go
index aa7c94e..28bd644 100644
--- a/server/server.go
+++ b/server/server.go
@@ -1,6 +1,9 @@
 package server
 
 import (
+	"log"
+	"net/url"
+
 	"github.com/ekzyis/zaply/env"
 	"github.com/ekzyis/zaply/lightning/phoenixd"
 	"github.com/ekzyis/zaply/lnurl"
@@ -22,11 +25,20 @@ func NewServer() *Server {
 		CustomTimeFormat: "2006-01-02 15:04:05.00000-0700",
 	}))
 
+	webhookPath := "/overlay/webhook"
+	webhookUrl, err := url.JoinPath(env.PublicUrl, webhookPath)
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	p := phoenixd.NewPhoenixd(
 		phoenixd.WithPhoenixdURL(env.PhoenixdURL),
 		phoenixd.WithPhoenixdLimitedAccessToken(env.PhoenixdLimitedAccessToken),
+		phoenixd.WithPhoenixdWebhookUrl(webhookUrl),
 	)
 
+	s.POST(webhookPath, p.WebhookHandler)
+
 	lnurl.Router(s.Echo, p)
 
 	return s