From f30363ff3929cd11e5974496eacb1a7c6bf46899 Mon Sep 17 00:00:00 2001
From: Overtorment <overtorment@gmail.com>
Date: Mon, 13 Jul 2020 14:43:13 +0100
Subject: [PATCH] FIX: groundcontrol notifications for internal invoices

---
 class/Invo.js      | 26 ++++++++++++++++++++++++++
 controllers/api.js | 27 ++++++++++++++++++++++-----
 doc/schema.md      |  1 +
 3 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/class/Invo.js b/class/Invo.js
index 093c309..8c77044 100644
--- a/class/Invo.js
+++ b/class/Invo.js
@@ -1,3 +1,4 @@
+var crypto = require('crypto');
 var lightningPayReq = require('bolt11');
 
 export class Invo {
@@ -65,6 +66,31 @@ export class Invo {
     return await this._redis.get('ispaid_' + paymentHash);
   }
 
+  async getPreimage() {
+    if (!this._bolt11) throw new Error('bolt11 is not provided');
+    const decoded = lightningPayReq.decode(this._bolt11);
+    let paymentHash = false;
+    for (const tag of decoded.tags) {
+      if (tag.tagName === 'payment_hash') {
+        paymentHash = tag.data;
+      }
+    }
+    if (!paymentHash) throw new Error('Could not find payment hash in invoice tags');
+    return await this._redis.get('preimage_for_' + paymentHash);
+  }
+
+  async savePreimage(preimageHex) {
+    const paymentHashHex = require('crypto').createHash('sha256').update(Buffer.from(preimageHex, 'hex')).digest('hex');
+    const key = 'preimage_for_' + paymentHashHex;
+    await this._redis.set(key, preimageHex);
+    await this._redis.expire(key, 3600 * 24 * 30); // 1 month
+  }
+
+  makePreimageHex() {
+    let buffer = crypto.randomBytes(32);
+    return buffer.toString('hex');
+  }
+
   /**
    * Queries LND ofr all user invoices
    *
diff --git a/controllers/api.js b/controllers/api.js
index 2870bd3..5cfba4d 100644
--- a/controllers/api.js
+++ b/controllers/api.js
@@ -54,8 +54,7 @@ redis.info(function (err, info) {
   }
 });
 
-let subscribeInvoicesCall = lightning.subscribeInvoices({});
-subscribeInvoicesCall.on('data', async function (response) {
+const subscribeInvoicesCallCallback = async function (response) {
   if (response.state === 'SETTLED') {
     const LightningInvoiceSettledNotification = {
       memo: response.memo,
@@ -94,7 +93,9 @@ subscribeInvoicesCall.on('data', async function (response) {
     );
     console.log('GroundControl:', apiResponse.originalResponse.status);
   }
-});
+};
+let subscribeInvoicesCall = lightning.subscribeInvoices({});
+subscribeInvoicesCall.on('data', subscribeInvoicesCallCallback);
 subscribeInvoicesCall.on('status', function (status) {
   // The current status of the stream.
 });
@@ -151,11 +152,14 @@ router.post('/addinvoice', postLimiter, async function(req, res) {
 
   if (!req.body.amt || /*stupid NaN*/ !(req.body.amt > 0)) return errorBadArguments(res);
 
-  lightning.addInvoice({ memo: req.body.memo, value: req.body.amt, expiry: 3600 * 24 }, async function(err, info) {
+  const invoice = new Invo(redis, bitcoinclient, lightning);
+  const r_preimage = invoice.makePreimageHex();
+  lightning.addInvoice({ memo: req.body.memo, value: req.body.amt, expiry: 3600 * 24, r_preimage: Buffer.from(r_preimage, 'hex').toString('base64') }, async function(err, info) {
     if (err) return errorLnd(res);
 
     info.pay_req = info.payment_request; // client backwards compatibility
     await u.saveUserInvoice(info);
+    await invoice.savePreimage(r_preimage);
 
     res.send(info);
   });
@@ -237,8 +241,21 @@ router.post('/payinvoice', async function(req, res) {
           pay_req: req.body.invoice,
         });
 
-        await UserPayee.setPaymentHashPaid(info.payment_hash);
+        const invoice = new Invo(redis, bitcoinclient, lightning);
+        invoice.setInvoice(req.body.invoice);
+        await invoice.markAsPaidInDatabase();
 
+        // now, faking LND callback about invoice paid:
+        const preimage = await invoice.getPreimage();
+        if (preimage) {
+          subscribeInvoicesCallCallback({
+            state: 'SETTLED',
+            memo: info.description,
+            r_preimage: Buffer.from(preimage, 'hex'),
+            r_hash: Buffer.from(info.payment_hash, 'hex'),
+            amt_paid_sat: +info.num_satoshis,
+          });
+        }
         await lock.releaseLock();
         return res.send(info);
       }
diff --git a/doc/schema.md b/doc/schema.md
index fb58b26..7f9b90e 100644
--- a/doc/schema.md
+++ b/doc/schema.md
@@ -11,6 +11,7 @@ User storage schema
 * refresh_token_for_{userid} = {access_token}
 * importing_{txid} = 1 `atomic lock when processing topup tx`
 * invoice_paying_for_{userid} = 1 `lock for when payinvoice is in progress`
+* preimage_for_{payment_hash_hex} = {preimage_hex} `ttl 1 month`